digital.library.unt.edu/67531/metadc872637/m2/1/high_res... · DISCLAIMER This report was prepared...
139
AECU-4438 PROGRESS REPORTS ACTIVATION ANALYSIS; NUCLEAR CHEMICAL RESEARCH; RADI OCHEMICAL SEPARATIONS Progress Report 8 for November 1958-October 1959 Edited by R. S. Maddock W. W. Meinke November 1. 1959 / University of Michigan Ann Arbor. Michigan UNITED STATES ATOMIC ENERGY CDMMISS10N Technical Wormation Service
Transcript of digital.library.unt.edu/67531/metadc872637/m2/1/high_res... · DISCLAIMER This report was prepared...
AECU-4438 PROGRESS REPORTS
ACTIVATION ANALYSIS; NUCLEAR CHEMICAL RESEARCH; RADI OCHEMICAL SEPARATIONS Progress Report 8 for November 1958-October 1959
Edited by R. S. Maddock W. W. Meinke
November 1. 1959 / University of Michigan Ann Arbor. Michigan
UNITED STATES ATOMIC ENERGY CDMMISS10N Technical Wormation Service
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
DISCLAIMER
Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.
L E G A L N O T I C E Thlm repert was prepred as .n ccrmnt d O o r e ~ t sponsor@ work. N a W r b Unttsd Nates. nor the Commiulon. aor .ey p s r m aclhl. on b a l d of the Commisskm
A. wakes ~ n y w v n n w o r r e m ~ w ~ t f o n , uprsased or imPUsd,wi(h re.goet to the accu- racy, compleimes0, or wcfulnsss of the informatton urn- h this report, o r that the w e of rag l ~ r ~ t t o n . sppuahtm, method. or proass. di~flosed in this -rt may not i~~ privately oMed rlgh1.; or
B. bsumes any UablUtIw wltb respect to the me of. or for damsges r e s u l w from Uls ulu, of rag inforrmtlou, amain& metbod, or paweas d i s c b a d in IhIs report.
As d in the .bovs. "person .cUng on -of the Cornmiasion" inolllder any em- PloyW or contmcbr of the Commlnion, or smploye d such contractor, to ths extent Ut ~ u c h employas es contractor ol the CommiM1lon. or employee of such urntractor prcpres. dfaaamlnatee, or mvldes acolum to. .ng lnform(~Uoa w a w t to 610 emploptlllt or contrc t alth the OommtBsion, or 61s employmoat vtth such c o ~ t r ' ~ .
This report has been reproduced directly from the best available copy,
Printed in USA. Price $2.75. Available from the Oflice of Technical Services, Department of Commerce, Washington 25, D. C.
DEPARTMENT OF CHEMISTRY
U N I V E R S I T Y O F M I C H I G A N
Ann Arbor, Michigan
PROGRESS REPORT .8 .
November 1958 - October 1959
ACTIVATION ANALYSIS
NUCLEAR CHEMICAL RESEARCH,
RADIOCHEMICAL SEPARATIONS / ' . .
R. S. Maddock
and
W . W . Meinke, ( ~ r d j e c t D i r e c t o r )
November 1, 1959
Suppor ted by
Depa.rtment of Chemistry
Michigan-Memorial Phoenix P r o j e c t
I P r o j e c t No. 7 Con t r ac t No. ~ ~ ( l l - 1 ) - 7 0 U. S . Atomic Energy Commission
The following is a report of the work completed on
Project No. 7, Contract No. ~~(11-1)-70 during the year
of November 1, 1958 to October 31, 1959.
Previous progress reports are listed below:
Progress Report 1
Progress -Report 2
Progress Report 3
November 1952
November 1953
November 1954
Progress Report 4 (AECU-3116) November 1955
Progress Report 5 (AEcu-3375) November 1956
Progress Report 6 (AECU-3641) November 1957
Progress Report 7 (AECU-3887) ~ovember 1958
TABLE OF CONTENTS
PAGE
. . . . . . . . . . . . . . . . . . . . . I FACILITIES 1
Michigan Reactor and Pneumatic Tube System . . . . 1 Thermal Neutron Fluxes and Cadmium Ratios in Pneue'tic Tubes . . . . . . . . . . . . . . . 4
Fast Neutx'on Measurements. in the Pneumatic Tubes . . . . . . . . . . . . . . . . 5
Investigation of Trace Polyethylene . . . . . . . . . . . . . . . . . contaminants 6
Determination of Neutron Attenuation by Rat Tissue . . . . . . . . . . . . . . . . . . . 7
. . . . . . . . . . . . . . . "Bunny Rabbitl"System 8
Typical Run Utilizing Pneumatic Systems . . 13
Neutron Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chemistry Building 21
. . . . . . . . . . . Problems of Air Conditioning 21
. . . . . . . . . . . . . . . . . . 11 INSTRUMENTATION 24
. . . . . . . . . . 100-Channel Pulse Height Analyzer 24
. . . . . . . . . . . . . . . . Auxiliary Circuits 26
. . . . . . . . . . . . . . . Additional Detectors 28
. . . . . . Three-inch Scintillation Crystal Detector 28
. . . . . . . . . . . . . . . . . . 111 .NUCLEAR CHEMISTRY 30
Absolute (d. alpha) Reaction Cross Sections . . . . . . . . . . . . and Excitation Functions 30
Nuclear Data ~nal~sis: Application of . . . . . . . . . . . . . . . . . Digital Computers 31
A Search for the Isotope Ir 196' . . . . . . . . . . 32 . . . . . . . . . . . . . Isomerism of Platinum.199 32
Preliminary Report on Etudy of Some Shark-Lived . . . . . . . . . . . . . . Fission Product Gases 33
TABLE OF ' CONTENTS (cont d )
Search.f,or Some Short-Lived Isomeric Transitions ; . . . . . . . . . . . . . . . . . . 37 .
. .
Isomerism of Silver-108 . . . . . . . . . . . . . . 37 .. . , .
New ~eterrnination of. the. ranch in^ Ratic of 2.4-min Silver-108 . . . . . . . . . . . . . . 39
Search for Rhodium-109 (Half-~ife 1 hr) in Fission Products . . . . . . . . . . . . . . .'40
Subcommittee on Radiochemistry Program. . . . . . . 41 Pamphlet on "Source Material for ~adiochemistry" . 41 Radiochemistry Monographs . . . . . . . . . . . . 42 Availability of' Cyclotron Service Irradiation Time. . . . . . . . . . . . . . . . . . . . . . 43
Radiochemical Separations of Cadmium. . - . .. . . . . 44 Application of Vacuum Distillation of Metals to Radiochemical Separations. . . . . . . . . . . 44
Radiochemical Separations by Amalgam,Exchange . . . 46 1 .
Experimental. . . . . . . . . . . . . . . . . . . 47 . .
Conclusion. . . . . . . . . . . . . . . . . . . 51 Expressing the Degree of Separation Obtained in a Radiochemical Separation . . . . . . . . . . 53
V ACTIVATION' ANALYSIS . . . . . . . . . . . . . . . . 58 Review Articles and Data Correlation Summaries. . . 58 Review Articles in Activation Analysis. . . . . . 58 Review of Fundamental Developments in Nucleonics. 58
Activation Analysis for Trace constituents' in. Meteorites. . . . . . . . . . . . . . . . . . . . 59
. .
Determination of Vanadium in Petroleum Process . . Streams. . . . . . . . . . . . . . . . . . . . . . 59
Determination of Vanadium in Petroleum Catalyst . . 60 Activation Analysis of Niobium. . . . . . . . . . . 63
THIS PAGE
WAS INTENTIONALLY
LEFT BLANK
TABLE 'OF CONTENTS (contld)
PAGE
Activation Analysis for Trace ~lements in Marine Organisms . . . . . . . . . . . . . . 88
Activation Analysis of Trace Cobalt. Vanadium and Copper in Tissue . . . . . . . . . . . . . . 89
Preliminary Investigations of (nYa). (nYp). and (n. y ) as Competing Reactions in Activation Analysis of Biological Tissue . . . . . . . . . 91
Preliminary Investigations of the Activation Analysis of Trace Selenium in Tissue Using
~e~~~~ ~e~~~~ and Se 81m . . . . . . . . . . . . 94 Preliminary Investigations on (n. 2n) Reactions ' for Activation Analysis of Carbon. Nitrogen and Oxygen . . . . . . . . . . . . . . . . . . . 96 Introduction . . . . . . . . . . . . . . . . . . 96
Procedure . . . . . . . . . . . . . . . . . . . . 97 Results . . . . . . . . . . . . . . . . . . . . 97
Discussion . . . . . . . . . . . . . . . . 99 Preliminary Experiments. for Activation Analysis of Thallium . . . . . . . . . . . . . . . . . 100
Radiochemical Analysis of Long-Lived Activity . . . . in a High Specific Activity Gold Sample 101
VI APPLICATIONS OF TRACERS TO ANALYSIS . . . . . . . 102 Use of Radioactive Tracers to Determine Solubility Products . . . . . . . . . . . . . . 102
VII SEPARATION PROCEDURES . . . . . . . . . . . . . . 103 Vanadium (~rownlee) . . . . . . . . . . . . . . 103 Vanadium (~aiser) . . . . . . . . . . . . . . . 104 Cobalt (Kaiser) . . . . . . . . . . . . . . . : 105 Copper (~aiser) . . . . . . . . . . . . . . . . 106 Niobium (~rownlee) . . . . . . . . . . . . . . . 107 Technetium (Fukai) . . . . . . . . . . . . . . . 108 Tungsten (Fukai) . . . . . . . . . . . . . . . . 110
TABLE OF CONTENTS ( c o n t d )
PAGE
Rhenium ( ~ u k a i ) . . , ~ '. . . . . . . . . . . . . . . 111
V I I I
G o l d ( F u k a i ) . . . . . . . . . . . . . . . . . . 1 1 2
~ h a l l i u m ' ( ~ i m ) . . . . . . . . . . . . . . . . . 113
PERSONNEL , PUBLICATIONS, TALKS, MEETINGS.
P a p e r s a n d R e p o r t s P u b l i s h e d . . . . . . . . . . . 115
T a l k s . . . . . . . . . . . . . . . . . . . . . . 117
Commi t t ee M e e t i n g s . . . . . . . . . . . . . . . . 1 2 0
I X ACKNOWLEDGEMENTS. . . . . . . . . , . . . . . . . 1 2 1
X LISTOFREFERENCES. . . . . . . . . . . . . . . . 1 2 2
v i i
TABLE OF CONTENTS ( c o n t ' d )
PAGE
Rhenium ( ~ u k a i ) . . . . . . . . . . . . . . . . 111 Gold ( ~ u k a i ) . . . . . . . . . . . . . . . . . . 1 1 2
T h a l l i u m ( ~ i m ) . . . . . . . . . . . . . . . . . 113
. . . . . V I I I PERSONNEL. PUBLICATIONS. TALKS. MEETINGS 114
P e r s o n n e l L i s t i n g . . . . . . . . . . . . . . . . 114
P a p e r s a n d R e p o r t s P u b l i s h e d . . . . . . . . . . . 115
T a l k s . . . . . . . . . . . . . . . . . . . . . . . 117
Committee Meetings . . . . . . . . . . . . . . . . 120
I X ACKNOWLEDGEMENTS . . . . . . . . . : . . . . . . . . 1 2 1
. . . . . . . . . . . . . . . . X *LIST OFREFERENCES 1 2 2
1
v i i
LIST OF, FIGURES . ,
FIGURE NO. PAGE , .
Quick opening polyethylene r a b b i t . . . . . . . 2
Thermal neut ron f l u x i n pneumatic tube no. 2 of Ford Nuclear React07 o p e r a t i n g . . . . . a t a power l e v e l of 1000 k w - lo$. 5
Neutron a t t e n u a t i o n experiment, t o p . . . . . . . . . . . . . . . . view of r a b b i t 7
Neutron a t t e n u a t i o n experiment, s i d e . . . . . . . . . . . . . . . . . . view of r a b b i t 7
' G a m m a d e t e c t o r f o r 100-channel a n a l y z e r ' . . . . . . . . s e t up i n h o t l a b n e x t t o hood 9
Spec t ra taken w i t h 1-1/2"x2It c r y s t a l i n hot l a b and w i t h 3"x3It. c r y s t a l i n 100-channel a n a l y z e r room. . . . . . . . . . -. - 1 0
. .
"Bunnynrabbit pneumatic t u b e l a y o u t . . . . . . 11 Layout of 3"x3" d e t e c t o r s e t u p . . . . . . . . 1 2
P i c t u r e s 1 through 10 show a t y p i c a l a c t i v a t i o n a n a l y s i s run u t i l i z i n g t h e pneumatic tube systems . . . . . . . 14
Two views of t h e neut ron g e n e r a t o r . . . . . 1 9
F l o o r p lan of Phoenix Laboratory showing ' . . . proposed housing f o r neut ron g e n e r a t o r 20
Radioisotope l a b o r a t o r y i n Chemistry Bui ld ing . 22
13. Counting room a d j a c e n t t o r a d i o i s o t o p e l a b o r a t o r y i n Chemistry Building. . . . . . . 22
. . . . . . . . . 14. 100-channe1,analyzer readout 25
15. Block diagram of a u x i l i a r y c i r c u i t s used w i t h . . . t h e 100-channel pu l se h e i g h t a n a l y z e r . 27
16. 3"x3It N ~ I ( T ~ ) c r y s t a l s e t u p i n 4 0 ~ x 4 0 " cave . . . . . . . . . - showing b e t a paddle i n p lace 29
17. Sample p repara t ion , f o r de terminat ion of krypton . . . . . . . . . . . . . . . . . . . 34
18. Sample p repara t ion f o r de terminat ion of xenon. 35
19. Gamma-ray spectrum of Ag ''Om produced i n 1951, 1954 and 1957. . . . . . . . . . . . . 38
v i i i
LIST OF FIGURES ( c o n t l d )
El'j'CfUm Nu, PAGE
20. Gamma s p e c t r a of c racking c a t a l y s t . . . . . . 61
21. C a l i b r a t i o n curve f o r vanadium i n . .
cracking c a t a l y s t . . . . . . . . . . . . . 63
94m 22. ~ e c a y scheme f o r Nb . . , . . . . . . . . . . ' . 64
23. amm ma s p e c t r a of niobium i n R u t i l e . . . . . . 65 '. .
24. K X-ray spectrum of niobium taken w i t h X-ray p r o p o r t i o n a l d e t e c t o r . . . . . . . . 66
25. C a l i b r a t i o n curve f o r go ld ( b i o l o g i c a l a s h ) . . : . . . . . . . . . . . 70
C a l i b r a t i o n curve f o r rhenium ( b i o l o g i c a l a s h ) . . . . . . . .. . . . . . . 74
spectrum of 63.5 kev gamma peak of Re 188m . :. 75 1 8 8 m Decay curves of R e .. . . . . . . . . . . . 76
Gamma s p e c t r a of Mo and Tc af ter 10 minute i r r a d i a t i o n . . . . . . . . . . . 78
Growth and decay o f TC'O' peak. . . . . . . . 79
C a l i b r a t i o n curve f o r molybdenum ( b i o l o g i c a l a s h ) . . . . . . . . . . . . . . 80
Gamma s p e c t r a of tungs ten a f t e r 6.3 hours i r r a d i a t i o n . . . . . . . . . . . . . . . . 83
C a l i b r a t i o n curve f o r tungs ten ( b i o l o g i c a l a s h ) . . . . . . . . . . . . . . 85
C a l i b r a t i o n curve f o r c o b a l t . . . . . . . . . 87
S ide view of cadmium-lined r a b b i t . . . . . . 93
C a l i b r a t i o n curve f o r carbon, n i t r o g e n andoxygen . . . . . . . . . . . . . . . . . 99
LIST .OF TABLES
TABLE
VII
VIII
NO. . 'PAGE
Dose Rates from -Fhbb.its, . . . .. , . . . ... : . . . . 3'
Fast Flux Data for. Pneumatic. .Tubes. at 1000 .Kw. . : 6
Preliminary Results from Rare Gas Experiment . 36
Decay Data for silver-108. . . . . . . . . . . 39
Exchange of an Element with its Amalgam. . . . 49 ~d~~~~ Exchange with Cadmium. Amalgam in 0.5 M NaNO Solution for Various Times of Stirring 50 3
T'1204 Exchange with Concentration of the Thallium Amalgam for Two Minutes Stirring. . 50
Interference of Noble Metals and Mercury . . . 51
Methods of Expressing the Degree of Separation that can be Obtained in a Radiochemical Separation . . . . . . . . . . . . . . . . . 54
Change in the Decontamination Factor with the Initial Concentration of,the Contaminant . . 56
Vanadium in Cracking Catalyst,, . . . . . . . . . 62
Approximate Experimenta1,Sensitivities and Mode of Chemical Separation for Six Trace Elements in Marine Biological Ashes. . . . . 90
~ctivities for competing ~eactions' . . . . . . 92
I FACILITIES
A . Michigan Reac to r and Pneumatic Tube System
The Ford Nuclear Reac to r has o p e r a t e d r o u t i n e l y a t a power of
1 megawatt ( f l u x of - 1013 n cm'2 s e c - l ) f o r t h e p a s t y e a r on an
average of t h r e e t o f o u r 8-hour days a week, w i t h two weeks o f f d u r i n g
t h e month of September f o r annual maintenance. O f t h e t o t a l number
of o p e r a t i n g hours o u r Nuclear Chemistry Group used 2450 hours of
running t i m e o b t a i n i n g 1090 i r r a d i a t i o n s . (sometimes s e v e r a l
people w e r e i r r a d i a t i n g a t t h e same t i m e . ) 1056 of t h e s e i r r a d i a t i o n s
were s h o r t i r r a d i a t i o n s made a t ' t h e c o r e u t i l i z i n g t h e pneumatic t u b e
system and 34 i r r a d i a t i o n s were beam p o r t o r " i n pool" i r r a d i a t i o n s .
The s h o r t i r r a d i a t i o n s are d i s c u s s e d i n more d e t a i l i n t h e s e c t i o n
on a c t i v a t i o n a n a l y s i s . The " i n pool" i r r a d i a t i o n s inc luded t h e
product ion of l o n g - l i v e d t r a c e r s such as Fe 117 59, cd115, 1n114 and Sn . Recen t ly an a r t i c l e has been pub l i shed i n Nucleonics ( 1 ) d e s c r i b i n g
t h e c u r r e n t s t a t u s of o u r f a c i l i t i e s .
The pneumatic t u b e system ( 2 , 3 ) has been i n f u l l o p e r a t i o n a lmost
con t inuous ly d u r i n g t h e y e a r . , Occasional problems have a r i s e n when
a r a b b i t has g o t t e n s t u c k , o r when a p r e s s - f i t r a b b i t has come a p a r t .
These problems, however, r e p r e s e n t o n l y a f e w t e n t h s of one p e r c e n t
o f ' o u r t o t a l number of i r r a d i a t i o n s . S i m i l a r l y w e have had some
t r o u b l e w i t h r e l a y s i n t h e c o n t r o l sys tem f o r t h e pneumatic t u b e s ,
and w e have asked t h e s u p p l i e r t o recheck and overhaul the system i n
October. This sys tem of f o u r pneumatic t u b e s , however, has been used
con t inuous ly f o r o v e r 2 y e a r s and has h e l d up ve ry w e l l under t h i s
h a r d use .
-Ithe m a t e r i a l f o r t h e r a b b i t s ( 3 ) used i n t h i s pneumatic system
was changed because t h e nylon o r i g i n a l l y , used became q u i t e b r i t t l e
a n d cracked a f t e r a number of hours i r r a d i a t i o n a t f u l l power. The
new des ign shown i n F i g . 1 i n c l u d e s t h e u s e ' o f po lye thy lene i n s t e a d . ' . . . . - i'
: ,
QUICK OPENING POLYETHYLENE' RABBIT '
MINOR DIA .875 12 THREADS PER IN. MAJOR DIA .983
.3 12 10 -32 THREADS TO LOCK ON 1/4 TURN
MATERIAL: BODY, CAP - POLYETHYLENE
SCREWS - NYLON BUMPERS, RIDERS - FELT
~ i ~ u r e 1 .. Quick opening pq lye thy lene . r a b b i t .
of nylon and a q u a r t e r t u rn t w i s t lock in s t ead of t h e p r e s s - f i t . . .
cap descr ibed previously ( 3 ) . It has been found t h a t polyethylene
w i l l l a s t a t l e a s t 2-3 t imes longer than t h e nylon and t h e q u a r t e r
t u r n cap can be opened j u s t a s f a s t a s t h e p r e s s - f i t caps .
1 Although t h e o r i g i n a l reason f o r choosing nylon was because
of i t s very low background a f t e r r a d i a t i o n , t h e dosage r a t e s from
a polyethylene r a b b i t a r e no t much g r e a t e r a s s h o w n ~ f o r pneumatic
tube No. 2 . i n Table I. ( 1 ) These values a r e s t i l l emall enough I
Table I. Dose Rates from Rabbi ts .
Surface dose r a t e s * (mr/hr)
I r r a d i a t i o n
t i m e Polyethylene Nylon
15 sec
1 min
2.5 min
5 min
- - -
*Measurements were made 3 sec a f t e r i r r a d i a t i o n a t 1 Mw.
t h a t dosage t o t h e hands i s n e g l i g i b l e dur ing t h e few seconds i t
t akes t o open a r a b b i t . F inger f i l m badges a r e always worn t o
record t h e dosage received dur ing a s e t of runs .
w To a s s u r e a reproducible placement of a sample In t h e r a b b i t ,
a small hollow cy l inde r of polyethylene is now u s e d . t o hold, the
sample i n t h e c e n t e r of t h e r abb i t .
The p o s s i b i l i t y of r e p l a c i n g t h e f e l t ' b u m p e r and gaske't of t h e
r a b b i t s w i t h p l a s t i c i s be ing i n v e s t i g a t e d s i n c e two' . to th rke . . t imes ' '
more r a d i o a c t i v i t y i s induced i n t h e f e l t , t h a n i n , t h e po lye thy lene . '
It i s hoped that a s ' u i t a b l e p l a s t i c can .'be , found ' t o r e p l a c e t h e f e l t ,
and t h u s c o n s i d e r a b l y reduce t h e t o t a l a c t i v i t y . '
s . . .
1. Thermal Neutron F luxes and Cadmium R a t i o s i n Pneumatic Tubes . .- .. . During t h e p a s t y e a r a r e c o r d has been k e p t of t h e the rmal
. .
neu t ron f l u x a t f u l l power i n Tube No. 2 ( s e e F i g . 3, ref . 3 )
w i t h o c c a s i o n a l checks of Tube No. 1 and Tube No. 3. The
average thermal neu t ron f l u x v a l u e s f o r t h e t u b e s a r e
Tube No. 1 1 . 7 6 x 1012 n sec - I
Tube Nb;. 2 ' 1 . 2 4 x 1012 11 11
. .
Tube No. 3 0.92 x 1012 11 I I
The average C d . r a t i o f o r Tube No. 2 was 1 4 . 7 and f o r Tube
No. 3 w a s 1 4 . 8 . One m i l . g o l d f o i l covered w i t h 2 0 m i l Cd f o i l
was used f o r t h e Cd r a t i o measurements.
F i g u r e 2 i s a p l o t of t h e day t o day f l u x measureme'nts
t aken i n Tube No:2 a t 1000 kw. The p r e c i s i o n of i n d i v i d u a l
p o i n t s should be b e t t e r than 3% based on known e r r o r s i n f o i l
weighing, p o s i t i o n i n g i n t h e r a b b l t , ' and coun t ing . t h e ' sample. .
' The measurements were made u s i n g 1 m i l g o l d f o i l s weighing
/( 1 . 5 mg t o g i v e count'ing r a t e s w i t h i n t h e u s e f u l range of ' t h e
s c i n t i l l a t i o n w e l l c o u n t e r .
The c a l c u l a t e d the rmai neu t ron f l u x ' w a s based .on a . c r o s s '
s e c t i o n (2200 m/s ) of 98 f o r . *ulg7. S i n c e t h e p u r p o s e of t h e
, f l u x moni to r ing program has been t o d e t e c t v a r i a t i o n s i n t h e
a v a i l a b l e f l u x , no c o r r e c t i o n s f o r self s h t e l d i n g and f l u x
depression of t h e sample have been made. The configurat ion of
t h e f u e l rods i n t h e r e a c t o r core i s changed only f o r . s p e c i a 1
experimental runs and remains t h e same f o r the f u l l power
operat ion used i n our work. The power l e v e l of t h e r e a c t o r a t
f u l l power i s given a s 1000 kw - + lo$. (H.w. Nass, D.G. Kaiser,
R . Fukai)
THERMAL FLUX IN PNEUMATIC TUBE NO. 2 n cme2 sec'l ( 1959)
' ,
I I I I I I I I I FEE. MARCH APR lL MAY JUNE JULY AUG. SEPT.
Figure 2. Thermal neutron, f l u x - i n pneumatic tube no. 2 df Ford Nuclear Reactor operat ing a t a power l e v e l of 1000 kw + lo$. - The 'p rec is ion of measurement of indiv idual poin ts should be b e t t e r than 3%.
2. Fas t Neutron Measurements i n the Pneumatic Tubes
Values f o r the f a s t f l u x i n the pneumatic tubes have been
redetermined a t 1000 'kw which i s now t h e r egu la r opera t ing power
l e v e l of t h e r e a c t o r . Fas t f l u x d a t a i s needed t o es t imate the
ex ten t r eac t ions such as t h e (n,p) and (n,a) can irllerfere with
the (n, y ) r e a c t i o n during a c t i v a t i o n ana lys i s .
el -24 The ~ 1 ~ ~ ( n , ~ ) ~ ~ ~ ~ , Mg2'(n,p)~a , and 1\127(n,p)~a24 reac t ions
. . . . . .. . .:. were used f o r the measurements i n the same manner as those made . . a t 100 kw (3) . Chemical separa t ions were not made. Samples were
, - r *. .
counted on the 3"x3" N ~ I ( T ~ ) c r y s t a l and s u i t a b l e cor rec t ions f o r ., . geometry, counting e f f i c i e n c y , decay scheme and peak-to- total
r a t i o were used i n order t o ob ta in the d i s i n t e g r a t i o n ra tes , of
1a2' and of t h e 840 kev y-ray of M ~ ~ ~ . The absolute d i s i n t e g r a t i o n
r a t e of the l a t t e r was obtained by sub t rac t ing the 1.04 Mev photo-
peak of ~g~~ out of the spectrum, using the' 1.11 Mev ~n~~ photo-
peak as a s tandard. The r e l a t i v e abundance of the 840 kev photo-
peak of M~~~ was taken as 68%. (J . ~ r o w n l e e )
Table 11. Fas t Flux Data f o r Pneumatic Tubes a t 1000 Kw.
Tube Rat io , ~ 1 ~ ~ ( n , p ) ~ ~ ~ ~ ~ g ~ ~ ( n , p ) ~ a 24 ~ l ~ ~ ( n , a ) N a 24
E n L 5.3 Mev En 2 6.3 Mev ~ ~ 2 8 . 6 Mev
Er ro r i s "standard devia t ion" . * 4 samples. ** 6 samples.
3. Inves t iga t ion of Trace Polyethylene Contaminants
The use of polyethylene tubing f o r sample conta iners was
found t o be both convenient and r e a d i l y adaptable t o the r ap id
procedures employed i n t h i s labora tory . Because some samples
were s tud ied without a chemical s epa ra t ion o r removal from these ,
conta iners , i t was necessary t o check.the polyethylene f o r t r a c e *
contaminants. I n t r m e d i c Polyethylene Tublng was i r r a d i a t e d
f o r t e n minutes a t one Megawatt and allowed t o decay f o r one
* Intramedic Polyethylene Tubing ( ~ e d i c a l Formulation PHF - ~ ~ 4 1 0 ) ;
Clay-Adams, Inc. , New York, N .Y.
minute. Gamma spectral determinations showed the presence of
sodium, chlorine, and aluminum. Sodium and chlorine were
sufficiently long-lived so as to offer few difficulties,
however, aluminum introduced an error in qualitative and
quantitative fluorine determinations. A quantitative deter-
mination showed that the aluminum concentration was in the
order of - 2. x g/g of polyethylene. (D. Kaiser)
4. Determination of Neutron Attenuation by Rat Tissue
Some of the biological samples studied during the course
of our investigation weighed between five and ten grams.
~lthough these samples were composed primarily of carbon,
hydrogen, oxygen, nitrogen, sulfur, and phosphorus, considerable
quantities of sodium, chlorine, manganese, and copper, in
addition to the trace elements, were also present. A study of c
neutron attenuation by biological tissue, specifically, rat
liver tissue, was undertaken to determine its magnitude.
An empty rabbit with gold foils around the exterior was
irradiated for one minute at one megawatt. The gold foils
were sealed in polyethylene film and scotch-taped in position
so that one foil was at each 45 degree increment (Fig. 3).
Figure 3. Neutron attenuation Figure 4. .Neutron attenuation experiment, top view of rabbit. experiment, side view of rabbit.
Two separate rows of-' foils'were.placed around the rabbit
one-half inch in from either felt washer (Fig.' 4). Thus the
rabbit vjas monitored both cross-sectionally and lon'gitudinally.
The same rabbit was then irradiated with a'liver sample
( W five grams) inside and a new set 'of gold foils around'th'e
exterior. The foil activities were compared within each
determination and between each determination. The data within
each determination indicated that the cross-sectional neutron
flux was decreased by 40% while the longitudinal irradiation
varied by 10%. Between each determination, the variation was
on the order of 2 - 3%. This would indicate that either the
biological sample reduced the neutron flux by 3% or the neutron
flux itself varied between the two determinations.
Since all of the foils monitoring the rabbit plus liver
sample were this low in activity, it was concluded that the . .
variation was due to neutron flux. (D. Kaiser)
B. "Bunny Rabbit" System
The temporary detector (3) for the 100-chanhel analyzer set
up,in the hot laboratory to ellminatz the 90-foot run down the hall
from lab to counting ro0.m proved unsatisfactory for measuring short
half-lived radioisotopes. The detector, a 1-1/2" x 2" N~I(T~) crystal
shielded with 4",of lead (Fig. 5) was set up on the floor of the hot
laboratory next to the hood and pneumatic tube station No. 2. With
this equipment it was.possible to begin spectral measurements within
a few seconds after the end of irradiation. However, the sensitivity.
attainable with this detector was poor due to the low gamma ray
detector f o r 100- channel analyzer s e t up i n hot l ab next t o hood.
counting ePficiency and the high background of radiat ion present i n
t he hot lab. Figure 6 shows spectra taken with the small c rys ta l i n
the l ab and with the 3" x 3" crys ta l i n the analyzer room ( a f t e r the
"bunny" system was ins ta l led) . The high cost of duplicating the
3'' x 3" crysta l s e t up i n the laboratory and the generally higher
background i n t h i s location encouraged u s t o t r y t o fifid other
solutions t o our rapid measurement problems.
This was f i n a l l y solved with t he i n s t a l l a t i on of a small pneumatic
tube system, the "bunny" rabbi t system, which can send a counting
sample from the l ab t o the analyzer room f o r counting with t he 3" x 3"
c rys ta l and then return it t o the hot lab. The bunny tubes a r e made
of 1/2 inch 1.d. aluminum pipe tha t is used i n a i r c r a f t f ue l l i n e s
and is readi ly available. Straight runs a r e EnUe or hard pipe and . bends of s o f t material. I n the system (Fig. 7) the tubing runs along
t h e eas t wall of the first f l o o r of the Phoenix Building from above
the hood housing Tube No. 2, t o the analyzer room, c i r c l e s the 3" x 3"
0 PULSE HEIGHT Figure 6. Spectra taken with 1-1/2"x2" c rys ta l in hot l a b and with
3"x3" crystal in 100-channel analyzer room.
VACUUM SUPPLY MASTER SWITCH
LENGTH J- SYSTEM I
HOLDING SOLENOID
OF VACUUM - 80 FT.
40" CAVE
MATERIAL: 12-FOOT LENGTHS-ALUMINUM TYPE 20-24 T3, I D 0.590U, OD 0.625" BENDS-ALUMINUM TYPE SO COUPLINGS -ALUMINUM TYPE 20-24 T3,3/4I8 SEALING COMPOUND, GLYPTAL 1201, RED
crystal inside the 40" x 40" cave as shown in Fig. b, ana returns
to the hot lab. The "send" switch is located at the hood station
while the "return" switch is in the analyzer room. The system is
completely enclosed and powered by a vacuum cleaner motor drawing
-6" of negative pressure.
SMALL PNEUMAVC A ~ \ ~ ~ ~ S TUBE SYSTEM DOOR
Figure 8. Layout of 3"x3" detector setup (looking down from above).
*
The 'samples, which are packaged in small polyethylene test tubes,
are stopped in front of the crystal by a forked plunger operated by I , . _ ' ~
.. . . .. :: a solenoid. When the sample is stopped by the plunger, there is a . . .,
pressure change on the vacuum side of the sample,which operates a
mercury switch shutting off the vacuum and starting the.analyzer . - . . . ' 1 Y I . .
, ,
through the auto-start circuit. (This is described in section 11' ~ .: - '
on Instrumentation.) The master control unit for the vacuum system - . . L , . I . : . I
. . - is located in the hot lab. The vacuum system can be run continuously . . . . 1 :v -,. '~ . . -. .. .. ., ,
.? ." . . . . - . . , . . , , , . n . , ' - d ~ .-
when desired. - ' . ,, . , . p, I ,,-- , ! ,,* . , .;-' : . 'U.. .~ .
! . . . . .< . - . . I
I . - . I I .
.. . , _ L r , I .
The time lapse for a sample from the reactor core to the < . - ' 8 -. . 7 ,
analyzer is w 15 seconds---three seconds from the core to the hood, - 10 seconds for transfer to a non-active container and 2 seconds to analyzer room and start of measurement. The auto-start circuit
allows one man to do a complete experiment on very short-lived materials
without assistance by controlling the analyzer from the laboratory.
(R. Shideler, H. Nass)
C. Typical Run Utilizing Pneumatic Systems
The potentialities of, and the techniques required for, the
facilities we have built up here can probably best be appreciated
through a series of pictures illustrating one particular run involving
a short-lived radioisotope. These pictures are. presented in Fig. 9. -, -2 It should be emphasized once more that at a flux of n cm
- -7 . sec-l, available at these pneumatic tube positions, we have found it
safe to catch the hot rabbit from a few minute irradiation in our R hands and open it manually. This entire procedure takes only 2-3 i . . I
seconds and finger badge records indicate a minimal exposure is , =." ~ . ' 8 ,, '?
. received during this time. Por reactors with pneumatic tubes , . I 8 . .~ . . .. . . . . . . I
operating at much higher fluxes these dosage considerations would * , , , '1 have to be rechecked.
8 . . '. . . . . . . . . . , .
. . . . - 8
. , , . . ~ ~>. .A-
Sample is. packaged in polyethylene ~ k j a .js #~'(~crrd la and put in a "rabbit.u f#g ' p ~ ~ . W t f ? tu'k @@-
y&)1~:b gtTfriB@ "ti .Srtf'@ ?tl# mZ@f@?.
The somple is held in the f ie ld of radiation for a pre- determined t ime.
Sample is returned' to the laboratory.
. -
m .- y. -ictures 1 thro
analysis run utilizing the pneum tube systems.
Sample is t ra~sf@rred to inocfive cpntgirier. Often. a Chernkql separation is also hgb.sse$,yi
I t stops in position in the cave which houses the gammo-ray detector.
The sample is loaded into the pneumatic tube system.
The dual 100-chonnel analyzer is outomaticolly turned on.
D. Neutron Generatoll
For a number of years our research group has been interested in
exploring the applications of activation analysis to different systems.
Starting in 1952 we began experiments with portable radium-beryllium
sources, we extended these later to antimony-beryllium sources, and
finally have been working for a year and a half with OUT Michigan
reactor. As we have explored the potentialities of this method it
has become very apparent that activation analysis will not be adopted
for routine analytical work industrially until some source of neutrons
8 9 is available which gives neutron fluxes of 10 -10 n cm-2 sec-I and
is considerably less expensive than the $100,000 required (a year
or two ago) for a small reactor or a Van de Graaf generator operating
with a zirconium-tritium target. (See page 689, ref. 4 for examples
of these sources.)
Several companies are at the present time exploring the feasi-
bility of producing neutron generators approximating these requirements
using Cockroft-Walton as well as Van de Graaf generators with
zirconium-tritium targets. Although fluxes now available are only 8' lo7-10 it would appear that within the next year or two it will be
possible to obtain a neutron generator for about $20,000 that would
9 have a flux of 10 n sec-I of them1 neutrons and could be
set up in one corner of a large laboratory. Thus the tools for
activation analysis would become comparable in price and space
requirements to other large analytical instruments such as the
emission spectrograph and the mass spectrograph.
One of the major problems of obtaining high fluxes with these
generators lies in the zirconium-tritium target. The life time of
this target is at best only a few hundred hours and thus the generators
will be useful primaGily for analyses involving short half-lived
radioisotopes. Since our group has had considerable experience working
with short half-lives with the Michigan reactor we felt we could
apply our experience to an evaluation of a neutron generator for
9 activation analysis. If a flux of 10 could be obtained eventually,
this would be only 1/1000 of the reactor flux we have been working
with and would still permit determination of 1 microgram amounts of
vanadium in oil samples, etc.
Consequently we have had correspondence with several companies
developing these neutron generators and have arranged with Dr. Norman
A. Bostrom, president of Texas Nuclear Corporation* to evaluate
their Model 100-1H Neutron Generator as a possible source of neutrons
for activation analysis. A generator simi?ar to that pictured in
Fig. 10 is being delivered in early October to the University of
Michigan.
This generator will be set up in the south east corner of the
accelerator room of the Phoenix Building in a position indicated by
the sketch of Fig. 11. The generator itself will be inside the
shielding while the control console will be outside. It is planned
to explore the potentialities of this machine both for thermal and
fast neutron activation analysis. Sensitivities for different elements
will be determined, as well as different operating parameters such as
the amount of shielding (and thus the amount of space) required,
optimum thermalized flux obtainable, etc. Two additional small
*Texas Nuclear Corporation, P. 0. Box 9267, Allandale Station, Austin 17, Texas.
Figure 10. Wo vlews of the neutron generator.
ACCELERATOR ROOM
PROPOSED SHIELDING FOR GENERATOR SENDING STATION
INTERCHANGE BOX
BUILDING MECHANICAL ROOM COBALT 60 SOURCE AND CAVE AREA
SOLIDHEAVY LINES SHOW PRESENT SMALL PNEUMATIC SYSTEM
\ VACUUM SUPPLY
CAVE DASHED HEAW LINES SHOW PROPOSED FOR SYSTEM ADDITION TO SYSTEM FROM NEUTAON @ENERATOR
FIRST LEVEL FLOOR PLAN PHOENIX LABORATORY
Figure 11. Floor plan of Phoenix Laboratory showing proposed
housing f o r neutron generator .
pneumatic ("bunny1') systems will be set up to take samples from the - -1
generator to the hot lab for chemical processing or to the 3" x 3" ' . . --gamma detector. Thus our facilities will permit meaningful comparisons, , A < , . . : 8 , . - - .
I f '~i!, (aetween analyses done on the reactor and those done with the generator. ., .
' ,JL2,, . - - . . . ' > c .a. A I - . W . e k e , R. Shideler) - ..
. , , . - . -, . ~
. . ~ . , 7 ,.c , = a , :: ','#:,!;;- . q L . + , 8 . . . - . J .I , ~, ., 88, . r '*,I -'
. . .. . , % . : : ,, ~. - r, I., . . ' . . . ; . . . " ' i r. .) L\;~,. . 'fd ' . . .2*n,,:;:;,;--,
" 7 , L . - .. . . ..,., ?..A. . '
. -~ ' . . . E . Chemistry Building . .. -~ I , i
I _ 1 ' . , .* , ' ;- J-L
J - , " ) -- L -
Remodeling of the teaching laboratory in the Chemistry Building
was completed in late fall of 1958 and gives us a first class radio-
isotope laboratory (~ig. 12). It is used for research two-thirds
of the time while for one semester a year it is used for the Nuclear
Chemical Techniques course. The counting room (~ig. 13) attached
to this laboratory is used primarily for the course since the
specialized counting room described previously (ref. 3, figs. 6, 7)
is air conditioned and humidity controlled to minimize day to day
variation in electronic performance.
F. Problems of Air Conditioning
, . :., . I " . . , , I ~ I - About 2 years ago orders were placed,to air condition the 100- #!: . < 2'. s,
,, . . -.=:r<&hannel analyzer room in the Phoenix Laboratory and the counting room I.
:r ' . . . A, -,i > I 8 I ; -1:' ., 1 -.,.,;;&n the Chemistry Building. These orders were to include not only *,-, . 1 - 3 - 7 , - k - , I
I :L?-, 'i - T I 7 .'C 8 7 . , . -., - temperature control to ~ O O F but also humidity Oontrol to 50 2 2$i.,, 2 .+: L .-- = - .,
~- <: J- . I 1
L ' In each case it took 4-6 months for the system to be designed and -;I-':,- 8 '
.,,I.' - : , , : IJ; ,;I..-- . : ~: installed, but workmen have been back on an average of once every 4 ;'i:r -I; - . . 8
I ,, . -- . I -- month or two ever since to repair or revise the ayatem. For some :! ' . 7 - . . 7: 6 i 4 1.
reason, whether because of iniLial poor planning, faulty equipment .-7
Figure 13. Counting room adjao
"I..--. 3try Building.
obtained from General Electpic and Frigidaire, or inexperienced
installation by Mlchigan personnel, neither facility has given
satisfactory performance for longer than 1 or 2 months at a time.
We try to maintain the temperature at 70' and the humidity at
5 6 . We have found that temperatures of 85' and above cause the
100-channel analyzer to operate erratically and a 95' and above room
temperature (meaning the temperature inside the analyzer is about
110') causes it to break down completely. High humidity, 65$ and
above, causes the memories of the analyzer to store erroneously or
not at all.
We have had similar problems with scalers used with a scintillation '
$ : t: well counter. At times when the air conditioning was inoperative C
all equipment had to be shut down completely. Some instruments
recover from the temperature spurts after a few days while others
require considerable electronics repair time and replacement of parts
before they will again operate satisfactorily.
The purpose of mentioning our experiences here I s twofold. One
is to emphasize the necessity for temperature and humidity control
for counting rooms. The other is a warning of the troubles that
can be encountered in trying to obtain this control with existing
equipment on the market. (W. W. ~einke)
I1 INSTRUMENTATION
A. 100-Channel Pulse Height Analyzer
During the past year the 100-channel analyzer room has remained
essen t ia l ly i n the same arrangement a s before ( ~ i g . 4; r e f . 3 ) .
The 100-channel analyzer (3) has been i n almost constant use
t o measure many dif ferent types of samples and radiat ions i n many
dif ferent problems. The analyzer has been used i n excess of 1660
hours during the year while w i t h preventive maintenance and rapid
repair , both memories have been out of commission* only .Y 32 hours
w h i l e in addition A uni t individually was down + 15 hours and B uni t
+ 32 hours.
Data can be obtained from the analyzer by looking a t the scope.
In addition, spectra can be recorded by printing out of values i n
each channel and the spectra can be plotted out d i rec t ly a s i n Fig. 14.
During t h e year the normal amount of tube and diode f a i l u re s
were encountered and repaired with l i t t l e l o s s of time. There were,
however, several major f a i l u re s which accounted f o r most of the down
time.
The B un i t had a memory f a i l u r e i n March which was traced t o a 5 bad magnetic core frame connection i n the 2 position. The spare frame
was connected i n w i t h minimum delay but the actual replacement of
t he bad frame took .Y 30 man hours.
The printing unit , Hewlett-Packard Model 560A, caused much
trouble by misprinting e i t he r erroneous numbers o r no numbers a t a l l .
-
*Down time is counted only when' analyzer is inoperative and one of the group needs t o use it.
The difrlculty was traced to a misalignment of the commutator discs.
These discs are held in place by four soldered bus bars and had been
inserted at an angle allowing the print wheels to miss their locking
positions. It was the incorrect spacing of the discs on the bus bars
that caused the difficulty. The repair is rather touchy and time
consuming, so a second print unit was obtained to eliminate long
down time. (The print wheels control the autograph recorder as well
as the tape printer. Thus if the printer goes out the only means of
using the analyzer is by looking at the scope.)
Other time consuming repairs involved the converter unit and the
Mosely autograph which has been installed on a sliding tray below the
printer assembly, Figure l4b. (H. Nass, R. Shideler)
B. Auxiliary Circuits
Several new auxiliary circuits for the analyzer have greatly
increased the versatility of the instrument.
The most important circuits added to the arialyzer were installed
in a small chassis just below the high voltage supply. The unit
contains a Hoogenboon summing circuit with a coincidence signal
inverting circuit and an alternator electronic switch.
The Hoogenboon summing circuit as described in Nuclear Instruments
(5) is used to gate either the coincidence or anticoincidence circuits.
The signal inverting circuit is necessary in order for the analyzer
to operate in anticoincidence, when by replacing a negative pulse
with a positive pulse the delayed coincidence circuit operates as
an anticoincidence gate (Fig. 15).
It was suggested that it might prove useful if we could take
alternating beta and gamma spectra. By using the control lines in
the analyzer and a relay this was accomplished. It is now possible
for "A memory" to store information from one crystal and "B memoryU
to store information from another crystal.
Two eight position ceramic switches were installed, a) to
control the high voltage for an auxiliary crystal (crystals other
than 3" x 3" crystal) in six steps and off, and b) to select the
signal input to the analyzer. A three position switch was installed
to control the signal inverting pulse and the alternating input
circuit.
By combining these circuits into one chassis in the analyzer
different types of spectra may be taken rapidly by merely tuning a
switch.
I:;::;I FI AUX. CRYSTAL
- HOOGENBOON 1 SUMMING CIRCUIT
I
r : 0
3"x 3" NORMAL / .. * , . r 0
AUX. CRYSTAL NORMAL * \ \ \
SW la . 3"x$" NORMAL
ANALYZER - . COINCIDENCE SUM SPECTRA / - SINGLE
* ,
- AUX. COINCIDENCE SUM SPECTRA
CHANNEL / 1, . UNIT -
SUM COINCIDENCE SPECTRA
INVERTER CIRCUIT
- TO DELAY COINCIDENCE - SINGLE ANALYZER CHANNELOUT , NEGATIVE CONTROL
'6" MEMORY U ALT.
CIRCUIT w Figure 15. Block diagram of auxiliary circuits used with
the 100-channel pulse height analyzer.
Another circuit incorporated in the analyzer is a holding
circuit which allows the analyzer to be placed in the auto-recycle
mode and held there until manually released or released by the
"bunny" system described earlier. This hold circuit consists of
two relays, two Grayhill switches, and a mercury switch. When the
system is put in readiness the relay circuits lock closed and "A
memory" is kept from storing while B unit remains quiescent. At
this time the analyzer is set for autoprint operation (both A and B
units). This circuit allows the experhentor to set up completely
the analyzer before starting his experiment and thus he does not have
to switch manually each individual unit into operation as before.
When the sample reaches the proper position in the "bunny" rabbit
system the mercury switch closes and the analyzer will automatically
start to store and print out spectra. (R. Shideler, H. Nass)
C. Additional Detectors
In addition to the 3" x 3" crystal previously described (3) there
are three other 2" photo tube-preamp units which can be used with
different crystals for coincidence and anticoincidence work. All
preamps are interchangable and may be used independently or in
conjunction with the 3" x 3" detector.
1
D. Three-inch Scintillation Crystal Detector
The 3" x 3" crystal unit housed in the 40" x 40" cave is now
permanently mounted on a track such that the unit can be slid forward
for repairs or locked into one position. The graduated sample holder
slides in and out of the cave nn nylon rollers. The holder is
stopped by blocks on the track in front of the 3" x 3" crystal
giving reproducible geometry. Mounted to one side of the orystal
a 2" phototube unit with a plastic phosphor elongated crystal whi
is used for removal of bremsstrahlung in gamma spectra. The
arrangement as shown in Figure 16 is very satisfactory and little
change in the cave arrangement is contemplated.
Figure 16. 3"x3" ~ a ( ~ 1 ) crystal setup in 40"x40" cave showing
beta paddle in place. Insert shows sauple holder
in counting position.
I11 NUCLEAR CHEMISTRY
' I
I Again during the past year the emphasis for our work has been
' on the Michigan reactor and only one cyclotron bombardment was r , obtained---to produce long-lived vanadium tracer for yield determina-
tions in activation analysis. No cross section measurements have
been made although some of the techniques and equipment have been
used in reactor flux measurements.
Since the auxiliary facilities for the reactor permit rapid
transfer of samples from reactor core to hood to counter (as described
in Section I) the decay schemes of a number of radioisotopes with
short half-lives have been studied.
A. Absolute (d, a1pha)Reaction -- Cross Sections and Excitation Functims
Hallls work (6) has finally been published in the Journal of
Inorganic and Nuclear Chemistry (7) as an az%icle entitled "Determination
of (d,a) Reaction Cross Sections1'. The following is an abstract of
this article.
"Absolute cross sections were determined for several
(d, alpha) reactions. Thin targets were bombarded by a
beam of 7.8-Mev deuterons which wsre collected in a Faraday
cup and measured by a current integrator. Product nuclei
were separated chemically from extraneous activities.
Absolute disintegration rates were determined by 4 pi
beta counting. Cross section values and estimated standard
deviations are reported for formation of the following
nuclei: ~ a ~ ~ , ~ a ~ ~ , ~ 3 ~ , scQ6, 68-min A ~ ~ ~ ~ , A ~ ~ ~ ~ , and A ~ ~ ~ ~ . ~ ~
Anderst manuscript on some later work is still in rough draft
form preliminary to submission to the Physical Review. (K. L. Hall,
0 . U. Anders) I . . . ,, .
B. Nuclear Data Analysis: Application of Digital Computers
This work has been summarized in a paper entitled "Method for
the Analysis of Multicomponent Exponential Decay Curves" recently
published in the Journal of Chemical Physics '(8): The following I .
abstract,accompanied this paper.
"A frequently encountered problem in many branches
of science involves the resolution of experimental data
into a sum of independent exponential curves of the form
in order to estimate the physically significant parameters
Ni and xi. Such problems arise, for example, in the
analysis of multicomponent radioactive decay curves, and
in the study of the dielectric properties of certain
compounds. This paper is concerned with the numerical
evaluation of a mathematical approach to the problem. The
approach is based on the inyersion of the Laplace integral
equRtion by a method of Fourier transforms. The results
of the analysis appear in the form of a frequency spectrum.
Each true peak in the spectrum indicates a component, the . .
abscissa value at the center of the peak is 'the decby . ,
constant , Ghile the height of the peak Is dire&ly proportional to ~ ~ / h ~ . Results obtained on an I B M 650
computer indicate.that the method may possess certain
advantages 'over previous methods of analysis."
(D. G. Gardner, J. C. Gardner, W. W. Meinke)
C. A Search for the Isotope Ir 196
The work on iridium isotopes mentioned previously (2) has
finally been published in the Physical Review (9). An abstract
follows.
The isotope 1rlg6 has been reported to have a half-
life of - 9 days and to emit B- particles with a maximum
energy of about 0.08 Mev. Using deuteron-bombarded enrichbd
isotopes of platinum, it is shown that the previous mass
assignment was incorrect. It is suggested that the - 9-day activity found in deuteron bombardments of natural platinum
is du'e to Ir and lrlgO produced by the (d,n) reaction on
osmium impurities. An experimental upper limit of 5 hours
for the 1rlg6 half -life can be set by these experiments.
Rough cross sections for the (d,o) reaction on ptlg4 and
ptlg6 are given for several 'deuteron energies from 9.6
(D G. Gardner,. W. W. Meinke)
D. Isomerism of platinum-199
The short-lived platinum activities (- 16.1 and 31 seconds)
' reported in the last progress report (3) were studied further. The
apparent 31 second activity was shown to be due to the presence of
small amounts of silver and rhodium impurities. Small gamma peaks
from the low yield gamma rays at 630 kev and 550 kev, of silver.
and rhodium,respectively, were found to be present to some extent
in all of our pur6 platinum samples. Careful half-life resolution
with good statistical counts also showed the correct half-lives for
. these contaminating activities.
A sample of platinum,enriched to 56.3% in ptlg8 was procured
from the Isotope Sales Division of Oak Ridge, for the study of the
shorter-lived gamma activity observed. This activity was shown to
be an unreported isomer of platinum-199. The results of this study
on Pt lggm have been presented in detail in a paper published in the
July 1, 1959 issue of the Physical Review (10). The abstract of
this paper follows.
" ~ n isomeric state of platinum-199 has been produced
by thermal-neutron irradiation of normal and enriched
platinum samples. The isomer decays with a half-life of
14.1 - + 0.3 seconds by the emission of y rays of 32 - + 2 and 393 - + 2 kev energy. The thermal-neutron activation
cross section of Pt lg8 for the formation of the isomer
is 0.028 - + 0.003 barn. Tentative level assignments are
made, consistent with systematics and shell theory."
(M. A. Wahlgren, W. W. Meinke) 6
. E. Preliminary Report on Study of Some Short-Lived Fission Product
Gases
'. Using the pneumatic tube irradiation facility, a miniature
charcoal adsorption system described below, and the "auto-start"
bunny'system with the one-hundred channel analyzer, it has been
p o s s i b l e t o s tudy t h e gamma spec t r a of 3)-second ~r", 41-second
xe13', and some of t h e longer- l ived f i s s i o n product r a r e gases .
For t h e rap id sepa ra t ion of K r samples, a sample conta in ing
uranyl n i t r a t e , and Nori te (charcoa l ) i s prepared i n a p iece of
1/4" i . d . polyethylene tub ing sea led on both ends by warming and
crimping s h u t . This system i s sketched i n f i g u r e 17. The Kleenex
Figure 17. Sample p repa ra t ion f o r de te rmina t ion of krypton.
pads a r e used a s spacers . t o contain t h e source ma te r i a l and t h e
charcoa l f i l t e r . IT he Nori te adsorbs Xe but K r d i f f u s e s through
i n t h e gas cham'ber.) The sample i s i r r a d i a t e d f o r 5-20 seconds,
removed from t h e r a b b i t and a gas sample of - 2 cc taken from t h e
gas chamber wi th a syr inge and hypodermic needle . The gas sample
i s t r a n s f e r r e d t o a se'cond -p iece of tubing sea l ed under p a r t i a l
vacuum. This t.ubing i s then placed i n t h e polyethylene'bunny which
is sea l ed wi th a t i g h t f i t t i n g polyethylene plug and s e n t t o t h e
d e t e c t o r .
For Xe samples t h e Nori te i s placed i n a p iece of tubing
connecting t h e needle t o t h e syr inge a s i n f i g u r e 18. Af t e r
URANYL KLEENEX NITRATE SPACER,
HYPODERMIC - NEEDLE
Figure 18. Sample p repa ra t ion f o r determinat ion of xenon. . ,
i r r a d i a t i o n of t h e sample and drawing a gas sample, t h e tubing i s
placed i n t h e bunny and sen t t o t h e counter . In t h i s case t h e Kr
passes through t h e f i l t e r i n t o t h e syr inge and i s d iscarded .
For some samples, t h e gas was allowed t o decay f o r two h a l f -
l i v e s , t h e r e s i d u a l gas 'removed by purging wi th a hot a i r stream, and
t h e sho r t - l i ved daughter a c t i v i t i e s observed.
The t ime requi red f o r handling, s epa ra t ion and t ranspor t . t o
t h e counter f o r r e g u l a r gas samples is 20-30 seconds. Operating
t h e ana lyzer a t 30 second r ecyc le it i s poss ib l e t o fo l low t h e decay
of t h e two sho r t - l i ved gases and t h e growth of t h e daughters f o r
s e v e r a l cyc l e s . The decay of t h e daughter a c t i v i t i e s i s then followed
on a longer recyc le per iod.
The gamma spec t r a of t h e daughters of t h e K r samples contained
t h e Fibgd and 13b8' gamma rays repor ted by o t h e r workers. The p u r i t y
of t h e Xe samples was e s t ab l i shed by sepa ra t ing 17-minute ~e~~~ and
138 fol lowing t h e growth and decay of 32-minute C s . The prel iminary r e s u l t s a r e summarized i n t h e fol lowing
t a b l e .
Table 111. P r e l i m i n a r y R e s u l t s from Rare Gas Experiment.
I s o t o p e Half - L i f e Major Gamma Rays (kev)
K r 89 -3 min complex, 210, 450, 600, o t h e r s
~b~~~ -1.7 min 100
X e 139 41 s e c 90, 150, 190, 270, 380, 520
X e 138 17 min 200, 420, f550) , 1760 2010 (220-1760 y-y co inc j
X e 137 -3.8 min no gamma r a y s observed
C s 140 66 s e c 590
The gamma-ray e n e r g i e s quoted a r e approximate due t o t h e h i g h
coun t ing r a t e s , and w i l l be e s t a b l i s h e d more- a c c u r a t e l y i n f u t u r e
r u n s . It may be p o s s i b l e t o estimate gamma-ray abundances from t h e
c a l c u l a t e d d i s i n t e g r a t i o n r a t e where a daugh te r a c t i v i t y w i t h a w e l l
c h a r a c t e r i z e d decay scheme i s observed. An a t t empt w i l l be made t o
e s t a b l i s h co inc idences by changing t h e geometry and obse rv ing sum
co inc idence peaks .
Uranyl n i t r a t e has been used as s o u r c e material a l t h o u g h t h e
. emanation of r a r e g a s e s from t h i s compound i s n o t a s complete o r
r a p i d as from c e r t a i n o rgan ic s a l t s .
It i s of i n t e r e s t t o n o t e t h a t t h e gamma spectrum o f ' g r o s s s h o r t -
l i v e d f i s s i o n p roduc t s shows s e v e r a l of t h e same gamma peaks. as
observed i n t h e s h o r t - l i v e d g a s e s . From f i s s i o n y i e l d and h a l f - l i f e '
c o n s i d e r a t i o n s t h e s e may w e l l be due t o ~ r ? ' and xe13'. (M. ~ a h l g r e n )
I?. Search for Some Short-Lived Isomeric Transitions
No unreported isomeric transitions of half-life greater than
3 seconds were detected in the gamma spectra of palladium, mercury,
rhenium, barium, and of a number of 99.9% pure rare earths obtained
from the Lindsay Chemical Company. The rare earths irradiated
consisted of samples of La, Ce, Pr, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb,
and Lu. When other longer-lived isotopes of these elements were also
formed in the irradiation this limit of 3 seconds is predicated
on a cross section within about 2 orders of magnitude of the long-
lived material. If its cross section is lower the "background" * activity would be so high that the half-life limits would be much
poorer. (M. ~ahlgren)
G. Isomerism of silver-108
A long-lived isomer of Ag108 has been detected in old Ag 11 Om
samples. The oldest available sample, produced in 1951 contains an
amount of. Ag considerably greater than the 0.05% Ag llOm (270 day)
activity remaining after 8 years of decay. The gamma-ray spectrum
of this activity, as well as those of similar samples produced in
1954 and 1957, is given in Fig. 19. .
The chemical assignment was confirmed by processing an aliquot
of the 1951 activity through a very thorough chemical purification
for silver. The mass assignment is based on the identity of the
beta ray and of one of the gamma rays observed in this activity
and in 2.4-minute Ag108, and is consistent with systematics of
neighboring nuclei, e.g. Rh, Ag, In. The half-life has been estimated
from the relative amounts of ~ ~ 1 0 8 m and AgllOm in the several samples,
- 0 656 - -
1957 Ag-l lOm
-
- 2 .4m Ag- 108
- - - -
0.5 1.0
ENERGY (Mev)
Figure 19. Gamma-ray spectrum of A g 'lorn produced
in 1951, 1954 and 1957.
b u t t h e u n c e r t a i n t y i n t h e h a l f - l i f e of Ag ''Om and i n t h e amount of
in! . t ial a c t i v i t y p rec lude any p r e c i s e h a l f - l i f e v a l u e f o r Aglosrn at
t h i s t ime . The s p e c i f i c a c t i v i t y of t h e a v a i l a b l e sample was t o o low t o
o b t a i n h i g h l y r e s o l v e d convers ion l i n e s p e c t r a t o un ique ly e s t a b l i s h
t h e i somer ic t r a n s i t i o n , b u t from gamma s p e c t r a and from co inc idence
r u n s , a c o n s i s t e n t decay scheme has been proposed.
This work has been summarized i n a p a p e r , s u b m i t t e d t o t h e
Phys ica l Review. The fo l lowing a b s t r a c t accompanied t h i s paper .
"A l o n g - l i v e d isomer of A~~~~ has been d e t e c t e d i n
o l d Ag ''Om samples. The isomer decays w i t h a h a l f - l i f e
> 5 y e a r s . Gamma- and b e t a - r a y spec t romete r d a t a show
t h a t 90% of t h e d i s i n t e g r a t i o n s proceed by- e l e c t r o n c a p t u r e
fo l lowed by a cascade of t h r e e gamma r a y s of 616, 722, and
434 kev energy, whi le 10% go by i s o m e r i c t r a n s i t i o n t o
Ag108. New v a l u e s a r e g iven f o r t h e branching r a t i d s of
108 1, 2.4-minute Ag . ( M . Wah1gren;W. W . ~ e i n k e )
H. New Determination of t h e Branching R a t i o s of 2.4-min S i lve r -108
The decay scheme of s i l v e r - 1 0 8 as g iven by St rominger , Hol lander
andSeaborg (11) was checked i n t h i s l a b o r a t o r y . The r e s u l t s a r e
summarized i n t h e t a b l e f o l l o w i n g .
Table IV. Decay Data f o r s i l v e r - 1 0 8 .
Rad ia t ion I s o t o p e Table Value New Value
1 . 7 7 Mev
0 .63
1 . 7 8
0.427
0.61
1.65 Mev 93.8% 0.632 Mev 1.90%
1.83 Mev 0.36%
0.434 Mev 0.18%
0.615 Mev 0.42%
The b e t a c o u n t e r was c a l i b r a t e d f o r t h i s experiment w i t h a
p3? sample s t a n d a r d i z e d on t h e 4 r c o u n t e r s . The g a q a peaks were
r e s o l v e d u s i n g t h e e f f i c i e n c y curves of Lazar ( 1 2 ) . The new v a l u e s
i n d i c a t e a f a c t o r of 2 e r r o r i n t h e b e t a c a l i b r a t i o n of t h e p rev ious
experiment. . It should be no ted t h a t t h e c a l i b r a t i o n e r r o r i s
q u a n t i t a t i v e on ly and does n o t a f f e c t t h e v a l i d i t y of t h e o r i g i n a l
s p i n and p a r i t y ass ignments . These d a t a w i l l be inc luded i n t h e
108m a r t i c l e on Ag . (M. Wahlgren )
I. Search f o r Rhodium-109 ( ~ a l f - ~ i f e <1 h r ) i n F i s s i o n Products
A r a p i d and s p e c i f i c chemical s e p a r a t i o n f o r rhodium was made.
i n s i x minutes from a uranium s o l u t i o n i r r a d i a t e d i n t h e r e a c t o r f o r
one minute. No b e t a o r gamma a c t i v i t y o t h e r than t h a t of 24-minute
rhodium-107 was d e t e c t e d . An upper l i m i t of one hour had been
p r e v i o u s l y e s t a b l i s h e d by S e i l e r (13) f o r t h e h a l f - l i f e of rhodium-
1 0 9 . From t h e new d a t a i t i s concluded t h a t any rhodium-109 formed i n
f i s s i o n m u s t be of h a l f - l i f e l e s s than one minute o r of f i s s i o n y i e l d
c o n s i d e r a b l y l e s s than t h e 0 .03s r e p o r t e d f o r t h e nex t member of t h e
f i s s i o n cha in , palladium-109. The chemical s e p a r a t i o n was e s s e n t i a l l y
t h a t used by Schindewolf and Wahlgren i n t h e a c t i v a t i o n a n a l y s i s of
m e t e o r i t e s f o r rhodium (1.4). (M. ~ a h l g r e n )
IV RADIOCHEMICAL SEPARATIONS .. . . .
This area has rece'ived considerable attention experimentally
during the year. DeVoe has completed his work on cadmium as .well as
on the exploration of radiochemical' separations by vacuum distillation.
In a'ddition' he has developed a new type of separation using amalgam
exchange which promises to be'very useful in the future for rapid
work.
considerable of the directoris time has been.taken up as
Chairman of the ~ubco.&nittee on Radiochemistry ,of the Committee on . .
Nuclear Science of the National Research Council, a job he assumed in
the Fall of 1958. Since then this Subcommittee has had three
meetings and has concerned itself with problems ranging 'from
avai1abilit.y of cyclotron-produced isotopes and cyclotron.irradiation
time to radiochemically pure re'agents and stockpiling of contamlnation- . .
free material. one of the major undertakings of this Subcommittee
is coordinating a series of monographs on the radiochemistry of
the elements.
A. Subcommittee. on Radiochemistry Program
. 1. Pamphlet on "Source Material for Radiochemistry" (15)
.The following statements appear in the foreward to this
pamphlet . "The field of radiochemistry,has no journal or .
other publication outlet to call its own. Some
abbreviated material is published in analytical or.
nuclear journals but seldom is a detailed radiochemical
sepa ra t i on procedure o r an e l a b o r a t e count ing
technique given f u l l p l ay i n t h e r e g u l a r l i t e r a t u r e .
Often d i f f e r e n t groups record t h e i r procedures i n
documents wh ich . a r e c i r c u l a t e d w i th in t h e framework
of t h e Atomic Energy Commission. Most of t h e s e
documents a r e a l s o a v a i l a b l e f o r s a l e bu t many t imes
t h e "ou t s ide r " i s no t aware of t h e r e p o r t o r of i t s
a v a i l a b i l i t y .
This compilat ion then i s an a t t empt t o l i s t
c u r r e n t source m a t e r i a l of i n t e r e s t t o t h e r ad io -
chemist . It has been compiled from l i s t s submit ted
by eac.h member of the ' Subcommittee on Radiochemistry.
Emphasis has been placed on documents and r e p o r t s of
a review n a t u r e which have proven u se fu l t o members
of t h i s Subcommittee. No a t t empt however has been
made t o inc lude s tandard a n a l y t i c a l r e f e r ence works
which of course a r e i n d i s p e n s i b l e i n planning new
procedures. 'I
Th is compila t ion c o n s i s t s of a l i s t i n g of about 60 i t ems .
Author., t i t l e , a s h o r t d e s c r i p t i o n of con ten t and a s ta tement
as t o a v a i l a b i l i t y i s included f o r each i tem. The -list w i l l
probably be r ev i s ed dur ing t h e s p r i n g of 1960 and r e i s sued .
Copies a r e a v a i l a b l e f r e e of charge from t h e Div i s ion of Physical
Sciences , Nat ional Research Council, 2101 Cons t i t u t i on Avenue,
Washington 25, D.C. (w. W. Meinke)
2 . Radiochemistry Monographs
The Subcommittee i s coo rd ina t i ng t h e p r epa ra t i on and
i s s u a n c e of a s e r i e s of .monographs on t h e rad iochemis t ry of
. t h e e lements . I n d i v i d u a l r e p o r t s a r e be ing p repared on one
o r s e v e r a l . r e l a t e d e lements and i n c l u d e a , d i s c u s s i o n .of t h e
f e a t u r e s of t h e chemis t ry of t h e element of p a r t i c u l a r i n t e r e s t
t o t h e rad iochemis t , comments .on t h e problems of g e t t i n g a
sample i n t o s o l u t i o n , and a d i s c u s s i o n of p r e p a r a t i o n and
coun t ing t echn iques . The r e p o r t concludes w i t h ' a n o u t l i n e of
s e v e r a l ' d e t a i l e d radioc'hemic&l procedures w i t h which t h e a u t h o r
i s f a m i l i a r and a l s o a c o l l e c t i o n of o t h e r procedures from t h e
pub l i shed r e p o r t l i t e r a t u r e .
~ u t h o r s a r e working on r e p o r t s f o r many of t h e e lements
now. About 1 0 of t h e r e p o r t s w i l l be completed by November and
a n o t h e r 1 0 o r 15 by e a r l y 1960. It i s planned t o i s s u e t h e s e
m ~ n o ~ r a ' ~ h s a s a series a l t h o u g h f i n a l ar rangements a r e n o t y e t
q u i t e complete. Up t o d a t e in fo rmat ion r e g a r d i n g t h e p u b l i c a t i o n
and a v a i l a b i l i t y of t h e s e r e p o r t s ' can be o b t a i n e d by w r i t i n g
t h e 'Divis ion of Phys ica l Sc iences , Na t iona l Research Council ,
2101 C o n s t i t u t i o n Ave., Washington 25, D . C . (w. W . Meinke) . .
3 . A v a i l a b i l i t y of Cyclotron S e r v i c e I r r a d i a t i o n Time
A q u e s t i o n a i r e was c i r c u l a t e d t o a l l c y c l o t r o n i n s t a l l a t i o n s
by t h e Subcommittee r e q u e s t i n g in fo rmat ion such as l o c a t i o n ,
p a r t i c l e s and e n e r g i e s a v a i l a b l e , whether t h e c y c l o t r o n would
o f t e n o r r a r e l y be k v a i i i b l e f o r work .of o u t s i d e groups , t h e
number of hours of such a v a i l a b i l i t y , whether t h e t a r g e t m u s t
be brought i n i n Person t o t h e f a c i l i t y o r whether it cou ld be
mai led i n and r e t u r n e d , and a s t a tement a s t o t h e r e s p o n s i b l e
i n d i v i d u a l t o whom a person should w r i t e r e g a r d i n g .scheduling
policies and tentative pricing information.
A summary of the information obtained in this questionaire
is available from the undersigned. (w. W. Meinke)
B. Radiochemical Separations of Cadmium
The study of the radiochemical separation of cadmium described
in the last progress report (3) has been published in the August 1959
issue of Analytical Chemistry (16). The abstract of this article is
as follows:
llRadiochemical separations of cadmium by solvent
extraction with dithizone in basic media, by ion exchange
in hydrochloric acid solution, and by two precipitation
methods, one with an organic'precipitant and the other with
a complex inorganic precipitant, have been developed,
allowing a maximum time of separation of 30 minutes per ,
method. These methods have also been critically evaluated
for yield and contamination using 18 typical tracers."
(J. R. DeVoe, W. W., Meinke)
C. Application of Vacuum Distillation of Metals to Radiochemical
Separations
The following 'is an abstract of a paper presented in the
Symposium on Radiochemical Analysis of the Analytical Chemistry
Division of the American Chemical Society at Atlantic City in
September, 1959.
"An exploratory investigation has been made to
determine the feasibility of effecting radiochemical
separations by distillation of the elemental state.
! ~ A vacuum was used to reduce oxide formation and to allow
better control of the vapor stream.
The distillation apparatus consists of a small chamber
- which is evacuated through a liquid nitrogen cold trap
by a Welch Duo-Vac pump. An equilibrium pressure of 6 x 10-~mrn
Hg can be achieved in 5 minutes. The sample to be distilled
is inserted into a cylindrical furnace made by drilling a
hole about 6 mrn in diameter axially into a carbon rod.
The rod is heated externally by means of an induction
heater. A heated Vycor deflector directs the vapor to a
liquid-nitrogen-cooled, cold finger around which is wrapped
a thin film of teflon. The distillate is collected on the
teflon which is then removed for counting in either a
Geiger or scintillation-well counter.
Systems investigated include the separation of mercury
by chemical reduction on a copper foil and subsequent
distillation. Yi-elds of about 70% and decontamination 3 4 . factors of 10 -10 were obtained in tests with traces of
20 typical elements. Electrolysis of cadmium-onto copper
foil (or into a mercury cathode with subsequent volatilizatim
of the macro mercury) followed by distillation proved
satisfactory if 1 rng of cadmium car.rier was used.
A study of the efficiency of separation by vacuum
distillation of Cd for various molar ratios of the metal
pairs.Cd-Zn and Cd-Ag has shown that entrainment of
contaml na n t s is an important limitat ion of the iilelflud.
A ve ry u s e f u l a p p l i c a t i o n of t h i s t echn ique i s t h e
s e p a r a t i o n of r e l a t i v e l y v o l a t i l e c a r r i e r - f r e e daugh te r s
from macro amounts p f n o n - v o l a t i l e p a r e n t such a s In l l 3 m
from i r r a d i a t e d t i n , Ag logm from i r r a d i a t e d pal ladium,
and Au lg9 from i r r a d i a t e d pla t inum. F o r t h e s e and f o r
o t h e r s u b s t a n c e s of s i m i l a r r e l a t i v e v o l a t i l i t y , vacuum
meta l d i s t i l l a t i o n can provide a r a p i d method f o r p r e p a r i n g
v e r y t h i n h i g h s p e c i f i c a c t i v i t y coun t ing sources . "
The equipment used f o r t h e s e exper iments was d e s c r i b e d i n t h e
p rev ious p rogress r e p o r t ( 3 ) . (J. R. ~ e ~ o e )
D. Radiochemical S e p a r a t i o n s by Amalgam Exchange
A new v e r y s e l e c t i v e radiochemical s e p a r a t i o n procedure has been
b developed by t h e use of amalgam exchange. The s e p a r a t i o n of t h e
r a d i o i s o t o p e t a k e s p l a c e 'by v i r t u e o,f t h e r a p i d exchange which i s
known t o occur between an element i n t h e form of a d i l u t e amalgam
and i t s i o n s i n s o l u t i o n s . If t h e r e a r e many more i n a c t i v e atoms
of t h e element i n t h e amalgam than t h e r e a r e of i t s r a d i o i s o t o p e i n !
s o l u t i o n , t h e amalgam exchange w i l l r e s u l t i n a lmos t a l l of t h e
~ a c t i v i t y be ing p r e s e n t i n t h e amalgam. Th i s amalgam exchange has
been found i n seve+a l c a s e s t o b e exceed ing ly r a p i d ( 1 7 ) , t h e r e f o r e
t h e method i s u s e f u l f o r t h e s e p a r a t i o n of s h o r t - l i v e d i s o t o p e s .
I T h i s method i s somewhat s i m i l a r t o t h e s i l v e r i s o t o p i c exchange
I method developed by Sunderman (18, 19) b u t a p p e a r s t o be much more
I wide ly a p p l i c a b l e .
The s e l e c t i v i t y occurs by v i r t u e of t h e f a c t t h a t t h e i o n s of
a n o t h e r contaminat ing element i n s o l u t i o n w i l l n o t exchange w i t h t h e
d e s i r e d element i n t h e amalgam. Because t h e r e i s l i t t l e mutual
in terac t ion between t h e phases t h e degree of s e p a r a t i o n i s e x c e p t i o n a l l y
h i g h .
A number of k i n e t i c s t u d i e s on t h i s amalgam exchange have been
- made. The exchange r a t e s of t h a l l i u m , cadmium, l e a d , z i n c , copper, ,
bismuth, sodium, potass ium .and cesium have been measured by Randles
I and Somerton ( 2 0 ) . Other work on t h e d e t a i l e d mechanisms of i n d i v i d u a l
I metal amalgam exchanges by t h e s e a u t h o r s i s a l s o a v a i l a b l e (21,,22,23).
E r s h l e r , ( 2 4 ) , has a l s o s t u d i e d t h e amalgam exchange. One of t h e
few r e f e r e n c e s t h a t o u t l f n e s t h e p r e p a r a t i o n s of v a r i o u s amalgams
i s g iven i n Booth ' s book ( 2 5 ) .
1. Experimental
Cadmium, z i n c , l e a d , t h a l l i u m , ga l l ium, t i n and indium
I amalgams can b e p repared by d i r e c t c o n t a c t of t h e meta l which
i s f r e e of o x i d a t i o n p roduc t s , w i t h mercury. T h i s c o n t a c t i s
I u s u a l l y made under d i l u t e a c i d , p r e f e r a b l y p e r c h l o r i c a c i d
which u s u a l l y forms s o l u b l e sa l ts . S o l u t i o n i s completed w i t h
g e n t l e h e a t i n g . The amalgams can be s t o r e d under 1-2 - M HC104
I t o keep a i r from t h e s u r f a c e of t h e a m l g a m ' a n d t o d i s s o l v e
any o x i d a t i o n p,roducts t h a t may form from t h e d i l u t e a c i d
s o l u t i o n . The c o n c e n t r a t i o n s of a l l amalgams a r e expressed i n
p e r c e n t by weight .
S t ron t ium amalgam was prepared i n t w . 0 ways: by a g i t a t i n g
an aqueous s t r o n t i u m s o l u t i o n w i t h sodium amalgam t h e s t r o n t i u m
i s reduced by t h e sodium amalgam and t h e p r e c i p i t a t e d s t r o n t i u m
t h e n d i s s o l v e s i n t h e mercury. Mercury ca thode e l e c t r o l y s i s of ,
a non-aqueous s o l u t i o n of a s t r o n t i u m salt i n a b s o l u t e e t h y l
a l c o h o l .is a l s o e f f e c t i v e . . .
An a t t e m p t t o p r e p a r e antimony amalgam and .niobium
amalgam was made by h e a t i n g t h e mercury and t h e meta l t o g e t h e r ,
t o 2 0 0 0 ~ ~ under p r e s s u r e . Because of inadequate des ign of t h e
a p p a r a t u s t h e methods were unsuccess fu l .
The f o l l o w i n g procedure i s used f o r t h e measurement of t h e
amount of t r a c e r exchange w i t h t h e amalgam.
1. Add t r a c e r ( n e g l i g i b l e volume) of t h e element t o be
exchanged t o a 50 m l pyrex c e n t r i f u g e cone and d i l u t e w i t h
2 ml 'of t h e e l e c t r o 1 y t e ; ' s t i r thorough ly .
2 . Take a 100 X a l i q u o t of t h i s s o l u t i o n and count .
3 . Put 1/2 t o 1 gm of a 2% (by w e i g h t ) amalgam (of t h e
d e s i r e d e lement ) i n t o t h e s o l u t i o n .
4. S t i r v i g o r o u s l y f o r 5 minutes . Count a 100 1 a l i q u o t
of t h i s s o l u t i o n .
5. C o r r e c t i n g f o r t h e a l i q u o t removed i n s t e p 2, c a l c u l a t e
t h e p e r c e n t a c t i v i t y which was removed from t h e s o l u t i o n . 1
The r e s u l t s of t h e amalgam exchange i n t h e e l e c t r o l y t e
which g i v e s t h e g r e a t e s t exchange, are l i s t e d i n Table V * The
r e s u l t s of a more d e t a i l e d s t u d y of t h e e f f e c t of t i m e of
s t i r r i n g on t h e exchange i s g iven i n Table V I . The e f f e c t of
i n c r e a s i n g c o n c e n t r a t i o n of t h a l l i u m amalgam on t h e exchange i s
g i v e n i n Table V I I .
S i n c e mercury reduces i o n s of t h e nob le metals, Au, P t ,
~ d , and Ag, and s i n c e mercury metal w i l l exchange w i t h i t s own
i o n s i n s o l u t i o n , t h e i n t e r f e r e n c e e f f e c t of t h e s e e lements . .
w a s s t u d i e d . The s o l u t i o n was stirred w i t h 1 0 gms of mercury . .
. . Table V. - ' Exchange of an Element with i t s Amalgam.
Element and mount Solution . -
Exchange $ of Isotope . .
5 - M HC1
. . 0.5 ' M - NaC104
0.5 - M Na2C204
0.5 - M NaN03
5 - M ~ ~ 1 0 ~
0.5 - M NaNO 3
s a t l d NaCl . .
2 - M ~ ~ 1 0 ~
2 - M HN03
0.5 - M NaN03
s a t ld NaCl
0.5 M NaNO - 3
11
none
11
I1
11
none
none
50-60
85
90
- - ---
*This value i s taken a t two minutes . s t i r r ing .
Table V I . ~d~~~~ Exchange, , . . . with Cadmium Amalgam i n 0 .5 - M NaNO 3 : So1ut;ioi.l ' f o r Various Times of ' S t i r r i n g .
. . .
. . . Time
. . fo 'r 1 min.
2
Table V I I . ~1~~~ Exchange wi th Concentration of t h e Thallium
Amalgam f o r TWO' Minutes S t i r r i n g .
Conc. of Amalgam ($) Exchange ($)
The
Table V I I I . I n t e r f e rence of Noble Metals and Mercury.
, Element (Amt). "Exchange" ($)
2. Conclusion
The amalgam exchange of t h e elements Cd, TI, Zn, Pb, Bi,
Sr , In , and Sn has been demonstrated. The e f f e c t on t h e exchange
of most common e l e c t r o l y t e s which do no t p r e c i p i t a t e t h e element
i s small.
Since t h i s work was intended t o determine t h e number of
elements which exchanged, l i t t l e was done wi th any p a r t i c u l a r
element. . Work that was done ind ica t ed that very i n t e r e s t i n g
s t u d i e s could be c a r r i e d out on t h e exchange process. The
elements with two oxida t ion s t a t e s such a s t ha l l i um ind ica t ed
unusual behavior by not exchanging upon prolonged s t i r r i n g , bu t
when s t i r r e d f o r a few minutes t h e exchange is very high. Increased
conocntrat ian of Lhe amalgam seemed t o i nc rease t h e exchange, a
f , ac t which i n v i t e s i n v e s t i g a t i o n i n t o t h e mechanism of t h i s e f f e c t .
An e f f o r t w i l l be made t o prepare amalgams of t h e r a r e
e a r t h s and t r a n s i t i o n metals t o i n v e s t i g a t e t h e i r exchange
p r o p e r t i e s .
Since mercury i t s e l f a c t s a s a reducing agent f o r t h e noble
metals a n d . s i n c e mercury w i l l r a p i d l y exchange wi th i t s own ions
i n so lu t ion , t h e bes t procedure f o r a genera l s epa ra t ion would
be t o scavenge these elements from t h e so lu t ion by a g i t a t i n g it
wi th pure mercury. Then t h e separa t ion of t h e des i r ed rad io iso tope
may be c a r r i e d out wi th t h e app ropr i a t e amalgam exchange.
There a r e s eve ra l problems involved with t h i s method of
s epa ra t ion . Several of t hese amalgams a r e known t o be reducing
agen t s which have nea r ly t h e reducing power of t h e pure metal
of which t h e amalgam i s made. This i s a p o t e n t i a l source of
contamination. One might r e so lve t h i s d i f f i c u l t y wi th t h e use
of a s e l e c t i v e scavenge s t e p s i m i l a r t o the .mercury reduct ion
that i s descr ibed above. In t h i s case one would scavenge wi th
an amalgam made wi th a metal j u s t below t h e des i r ed one i n t h e
e lectromotive s e r i e s .
A t t h e end of t h e separa t ion t h e a c t i v i t y i s i n t h e amalgam.
If t h e ma'dor a c t i v i t y i s from B p a r t i c l e s t h e mercury would
a c t a s an absorber and cause s e r i o u s s e l f absorp t ion e r r o r s .
If t h e a c t i v i t y i s from y r ay emission t h e e r r o r i s less and
may no t be g r e a t enough t o prevent use of a co r r ec t ion f a c t o r .
In any case it may be poss ib le t o s e l e c t i v e l y s t r i p t h e element '
from t h e mercury e i t h e r by an a c i d wash o r by e l e c t r o l y t i c
s t r i p p i n g , and thereby reclaim t h e pure a c t i v i t y wi th c a r r i e r .
It i s our i n t e n t i o n t o explore t hese problems i n connection
with the detailed study of radiochemical separations by
amalgam exchange of the metals mentioned above, and of others
I - if the exchange can be demonstrated. (J. DeVoe, C. Kim)
. .
I " E. Expressing the ~ e ~ r e e of separation' Obtained in a Radiochemical
Separation
At the present time there has been no consistent method for
reporting the degree of separation obtained from a radiochemical
separation. In fact there has been little attempt to define the
various terms which have been used. *This is probably due to the fact
that most of the terms seem self explanatory'at first glance. However,
it ap p e ar s that improperly def ined terms have resulted in misinter-
pretation of separation data. The various possible method of
expressing the efficiency of a radiochemical separation are listed
1 in Table VIII. These definitions in Table.VII1 have been made with
~ the intention of paralleling as closely as possible. the meaning
~ intended in previous reports. (18,26,27) The percent yield is also
listed in Table IX. Expression 5 is not referenced in the litera-
ture, but represents another possible expression using the same
I . .variables as in 1 and 2. I
It is difficult to adequately express the degree of separation
I of a radiochemical separation., The most logical approach to solving . .
. .
this problem would be'to note the applications of most radiochemical I
separations as described in Chapter 1 of reference 28. The amount of
activity of the contaminant which is measured with the desired activity
I& the most important conside~ation. Therefore, the efficiency of
the separation should be expressed as a percent contamination.
Usually the method of reporting the data should be as general as
. .
Table I X . Methods of Expressing t h e Degree of Separat ion
t h a t can be Obtained i n a Radiochemical Separat ion.
1. DECONTAMINATION FACTOR ";/Al
2. PERCENT CONTAMINANT CARRIED (A / A f ) l O O 1 1
3. . ' PERCENT YIELD (AJA;) loo
4. ,PERCENT CONTAMINATION (n1/nO ) l o o
A; a c t i v i t y (c/m) of contaminant p resen t i n i t i a l l y
' A1 a c t i v i t y (c/m) of coneaminant p resen t wi th des i r ed ' . '
q c o n s t i t u e n t a f t e r separa t ion
A; a c t i v i t y (c/m) of des i r ed c o n s t i t u e n t i n i t i a l l y
A. a c t i v i t y (c/m) of des i r ed c o n s t i t u e n t a f t e r separa t ion
poss ib l e . In each c a s e . t h e a c t i v i t y w i l l be counted wi th some type
of counter ( s c i n t i l l a t i o n , Geiger-Muller, o r p ropor t iona l coun te r ) .
Refer r ing t o Table V I I I it can be seen t h a t t h e A1 and A. r e f e r t o
. two e n t i r e l y d i f f e r e n t r ad ioac t ive nuc l ides which would o r d i n a r i l y
have d i f f e r e n t counting e f f i c i e n c i e s f o r t h e emit ted r a d i a t i o n when
us ing any given type of counter . Therefore, t h i s method of r epo r t ing
d a t a i s not very genera l , and t h e percent contamination changes wi th
t h e type of counter used because t h e count ing e f f i c i e n c y of a given
nuc l ide would b e d i f f e r e n t f o r each type of counter .
If t h e d a t a a r e repor ted a s a decontamina t ion . fac tor , percent
decontamination, .or percent c a r r i e d ( a l l involving .the same v a r i a b l e s )
t h e d i f f i c u l t y . involving changes i n counting e f f i c i ency , and counter
a r e removed because t h e same nuc.lide i s measured before and a f t e r
t h e separa t ion . There a r e , however, two a d d i t i o n a l d i f f i c u l t i e s - which a r i s e . The decontamination f a c t o r w i l l not "a p r i o r i " t o
a c t u a l experimentation i n d i c a t e whether t h e radiochemical separa t ion
w i l l be good enough t o remove t h e contaminants t o a l e v e l below t h e
s e n s i t i v i t y of t h e counting instrument which w i l l be u'sed, o r t o a
l e v e l below which no i n t e r f e r e n c e r e s u l t s . This i s not a s e r i o u s
d i f f i c u l t y because t h e decontamination f a c t o r s t i l l g ives a genera l
i nd i ca t ion of t h e degree of t h e s epa ra t ion which may be obtained.
In a given experiment it may be necessary t o r epea t t h e s epa ra t ion
procedure t o g e t t h e t o t a l des i r ed degree of separa t ion .
The second d i f f i c u l t y i s more. s e r i o u s because it a f f e c t s t h e
g e n e r a l i t y of t h e da t a . The decontamination f a c t o r i s o f t e n dependent s p e c i f i c
upon t h e concent ra t ions of t h e contaminant of a g iven ,ac t iv i ty . I n
t h e s p e c i f i c case of a separa t ion by p r e c i p i t a t i o n , however, t h e usual
procedure i s t o add 1 0 mg. of i n a c t i v e c a r r i e r of t h e des i r ed a c t i v i t y ,
and a s long a s t h e p r e c i p i t a n t i s i n excess, . t h e decontamination
f a c t o r i s constant over a wide range of concent ra t ions of t h e
contaminants.
I n the case of a sepa ra t ion where contamination occurs a s a r e s u l t of
su r f ace adsorp t ion f o r example, t h e decontamination f a c t o r i s l a r g e l y
dependent on t h e concent ra t ions of both contaminant and t h e des i r ed . oonot i tuen t . Suppose t h a t t h e contaminating e f f e c t i s . s u r f a c e
adsorp t ion of t h e form ind ica t ed by the Freundlicls f s o t h e m Y = KC l /n
where Y = mass of contaminant adsorbed per u n i t mass of adsorbent ,
C = concentration of contaminant .in the medium- in which the.absorber
exists, and n, K = empirical constants. .The decontamination factor
per unit mass of absorbent per unit volume of the medium is expressed
c - as D.F. = y yn - 'K"+1C1/" ' From this it .is clear that ,if: n > 0 the
de~~ltamination factor is dependent on both the concentration of
desired constituent and the contaminant. .An.example of this general
effect can be found in a copper foil experiment where copper is used
to reduce trace amounts of mercury onto the solid copper metal foil.
The procedure involves the reduction of 16 Mgm of mercuric ion onto
'the copper. in ,the presence of ~ossibly contaminating ions which are
labeled with its radioactive Isotope. The degree of separation of
mercury from different concentratibns of contaminants is listed in
Table X. Since neither barium, lanthanum or Indium will be reduced
by copper the contamination which is observed is due to some other
factor,.such as surface absorption. These data clearly show the
dependency of the decontamination factor on the concentration of the
Table X. Change in the Decontamination Factor with the
Initial Concentration of the Contaminant.
--
Contaminant Activity of Amount of Activity on Decont . Cont. added Con tam. Copper c/m Factor
Ba-La 140 . 1 . g x 1 0 6 c .F. 5,700 3 x lo2
Ba -La 140 1.9 lo9 C.F. 8,000 2.6 x lo5. Inl14 4.8 X . 10 6 4.6 g 48 105
In 114 4.4 x. 10 8 0.5 mg 19 2 x 107
contaminant. These data represent only a few examples of the effect. . .
It is necessary therefore to indicate the quantities of both
the desired constituent and the contaminants when effects of this
kind are expected. This difficulty is not particularly restrictive . ,
because the direction of the effect can often be predicted. In the
case of surface adsorption which .follows relations similar to 'the
Freundlich isotherm one can predict that at higher concentrations of . . .
the contaminant the decontamination factor increases., This indicates. 4 . .
an even better separation.
,Ideally, to unambigously express the degree of a separation,
recourse must be taken to discussing inactive atoms on a mole fraction
basis or mole percent contamination. For a radiochemical separation
this is not general for reasons discussed before. , . . .
For radiochemical separations the.most general.method of.express-
ing the degree of the separation is with the decontamination.factor
or its associated, percent contaminant carried, indicating the quantities
(gram moles) concerned when the mechanism of the separation as .
explained above indicates that this is necessary. (J. ~ e ~ o e )
. . . . . . V ACTIVATION ANALYSIS
. . . .
With t h e r e a c t o r opera t ing cont inuously a t 1 megawatt dur ing 1 , ,! .: . . ' \
I ' .
t h e pas t year and wi th t h e pneumatic tube f a c i l i t i e s and spec i a l i zed . ' 1
ins t rumenta t ion descr ibed e a r l i e r i n f u l l operat ion we had unpara l le led h
f a c i l i t i e s f o r s tudying t h e a p p l i c a t i o n . of a c t i v a t i o n a n a l y s i s t o
many types of systems. In many cases t hese s t u d i e s emphasized t h e
use of sho r t - l i ved rad ' ioisotopes i n t h e a n a l y s i s .
: A . Review A r t i c l e s and Data Corre la t ion Summaries
1. Review A r t i c l e s i n Act iva t ion Analysis . ,.
. An a r t i c l e presen t ing 3 s e n s i t i v i t y graphs computed on t h e . .,
.12 cm-2 ' b a s i s of a t he rma l n e u t r o n . f l u x of 10 sec- I and
i r r a d i a t i o n ' t imes ' of 6 minutes, 600. minutes (10 "hours ) and
1000 hours was 'pub l i shed . in the.May 1959 i s s u e o f .Ana ly t i ca1
Chemistry (29')'. The a r t i c l e by..Fouarge on Chemical Analysis by
. A c t i v a t i o n ~ w i t h Neutrons was published i n t h e February, 1959
i s s u e of I n d u s t r i e Chimique Belge (30) .
The a r t i c l e e n t i t l e d "Trace ~ n a l y s i s of Marine Organisms:
A Comparison of Act iva t ion Analysis and Conventional Methods"
' by R. Fukai and W . W. Meinke is appearing i n t h e October 1959 . .
' i s s u e of Lirnnology and Oceanography (31) .
2. Review of Fun.damenta1 Developments i n Nucleonics , .
Considerable e f f o r t has been expended i n reviewing t.he
l i t e r a t u r e of t h e p a s t 2 yea r s f o r t h e new biannual review. It
w i l l extend from l a t e 1957 u n t i l l a t e 1959 without overlapping
the previous review (4). The deadline for submission of the
manuscript to Analytical Chemistry is.December 1, 1959. It
will appear in the Review Supplement to the April, 1960 issue
of that journal. Indications are that there will be more than
.- 1000 references included, with Russian literature occupying a
more prominent position than previously. (w. W. ~einke)
. B. Activation Analysis for Trace Constituents in .Meteorites
Articles on the rhodium, silver and indium (14) as well as the
selenium and tellurium (32) content of chondritic meteorites have
beln submitted to Geochimica et ~osmohhimica ~ c t a . The first one
will be published in a fall issue. The content of these articles
was reviewed in the last progress report (3).
(u. Schindewolf, M. Wahlgren)
C. Determination of Vanadium in Petroleum Process Streams
As was reported previously (3), a method has been developed for
the non-destructive determination of vanadium in petroleum process
streams by neutron activation and gamma scintillation spectrometry.
This work was performed at a time when the Ford Nuclear Reactor at
the University of Michigan was operating at a power level of 100 kw,
producing a thermal neutron flux in the pneumatic tubes of the order
The sensitivity for this determination has since been redetermined
with the reactor operating routinely at a power level of 1000 kw,
producing a pneumatic tube thermal neutron f lux of the ordtp uT
-2 -1 1012 n cm sec , and has been found , t o be increased by a f a c t o r
of 10.0 - + 0.1 over t h e s e n s i t i v i t y as determined a t . lOO kw. This
t en - fo ld inc rease i n s e n s i t i v i t y has, however, g i v e n . r i s e t o a .
c e r t a i n amount of i n t e r f e r e n c e due t o a sodium-24 photopeak i n some
of t h e samples which was not apparent i n t hese samples when i r r a d i a t e d -.
a t 100 kw. By s u i t a b l e "cool ing" t imes, however, t h i s i n t e r f e r e n c e
can be co r r ec t ed f o r , and amounts of vanadium as low a s 2.5 x lo-' . grams i n approximately 150 mil l igrams of an o i l sample can be
determined without chemtcal s epa ra t ion .
This method has been presented before t h e Apr i l , 1958 meeting
of t h e American Chemical Soc ie ty , and i s being prepared f o r submission
i n t h e nea r f u t u r e t o Analy t ica l Chemistry. (J. Brownlee, W . W . Meinke)
,D. .Determination of Vanadium i n Petroleum Cata lys t
Inasmuch a s 1,ow concent ra t ions of c e r t a i n elements, inc lud ing
vanadium, tend t o reduce . t h e . a c t i v i t y of a cracking c a t a l y s t ,
t h e r e i s a pronounced i n t e r e s t on t h e p a r t of petroleum r e f i n e r s
i n t h e amount of t h e s e elements depos i ted on t h e c a t a l y s t . We have .
thus ' extended our work on o i l samples t o include t h e s e s o l i d c a t a l y s t s .
The c a t a l y s t samples (k ind ly furn ished by 0 . I. Milner of . .
.~ocony-Mobil O i l company) have a s i l i c o n dioxide - aluminum oxide
base and may a l s o conta in small amounts of chromium, i ron , t i t an ium
and zirconium oxides . The gamma spectrum of a r ep re sen ta t ive sample
( . ~ i g . 20) shows a very l a r g e aluminum photopeak, i n add i t i on t o
28 . sma l l e r vanadium and s i l i c o n photopeaks superimposed on t h e A 1
Compton s c a t t e r d i s t r i b u t i o n . Because of t h e presence of r e l a t i v e l y
l a r g e amounts of aluminum, a chemical s epa ra t ion of t h e vanadium
- . 7 .. - . , , , /;7L - . . . ,. . .. . . A'.
0 CHANNEL NUMBER
Bigure 20. Gamma spectra of cracking ca ta lys t .
was deemed necessary f o r any reasonably accurate determination. The
major problem i n such a separation l i e s i n the complete removal of
aluminum, inasmuch a s the other materials present i n the cata lys t
give r i s e t o gamma photopeaks of energies lower than t h a t of vanadium, , . ,, 8
8 . , ..
and hence would not i n t e r f e r e with a vanadium determination. ,I
- 1 . . ~ . , . . , . . .. . - - . , . Samples of ca ta lys t used f o r t he vanadium deterinination were . . . . - . , .. . < '
. 4 ',:;I,. , 8 ' , ? ' : : 41, . .- t rea ted i n t he following manner: Forty t o one hundred milligrams of ; . ,K- > . , 1
- , = .!.#, , t . . ( I . ' . , , I:, ., I i , . , f inely ground cata lys t is weighed in to a gela t ine capsule and . . . . - I1
- l . I . ' '
r i ' T.. ;, . . .!': 4d , ,"': , . , 'i ; , , - , A - ;: f. 9, : .: - = ' i r rad ia ted i n a pneumatic tube f o r ten minutes. The i r r a d i a t e d , - - E -,&<!, , , .. I il , - ' , , ,,.:,: . .
1 -=---I ' 1 :' ' 8
, ' , '
.I, .a4-'. capsule i s then fused i n 3-3.5 grams of sodium peroxide containing : ' . :L . .:
7 y: -. , , T .+I .. a known amount of v~~ ac t iv i ty , cooled rapidly by repeatedly dipping J " ' ,tt -- -.T, -
, , ' .''ill:$r the bottom of the crucible i n to cold water, and the melt d i s ~ o l v e d . . T-*
- - - I : !b-J -;! 4-t
' .:. :.> - \
i n 100-ku of a solution containing aluminum and vanadium car r ie r s , , . 8 ,
1 : , ~ ' i /
: L. , ..' . , - ' I ,. . . . . , L . , , -,! r !, ,,;,.:I;';,, '. ,,
- . . - . C - . r I . . . -.>,'. : - . , r > . ,,_ . ,, I . - ' 8
. . ' I ' . -, I , . '. . ; . , . . . 8 ' . I . . ,; . . . . . .. . . , , , . , . . . ., .
. , . . . . .
62 . ~
hydrochl.or1c acid and 3 percent hydrogen' peroxide. Aluminum is
removed by precipitation<with 8-hydroxquinoline in acetic acid and
filtration through a medium glass frit. The filtrate is acidified,
and vanadium extracted into chloroform with cupferron. The chloroform
layer is analyzed on the 100-channel analyzer, counting being started
exactly ten minutes after removal of the sample from the reactor.
@ more detailed description of this radiochemical procedure is given
in tbe section on Separation Procedures.) Successive spectra were
recorded every minute for several minutes. In these spectra, v~~ had the most prominent photopeak, with no photopeaks appearing having
gamma energies higher than that of vanadium. The v~~ tracer provided data on the chemical recovery of vanadium.
The activity found under this photopeak, after being corrected
for background radiation, variations in flux, and chemical recovery
of vanadium, is related to the amount of vanadium present in the
sample as shown in Figure 21. Typical analysis of samples are given
in Table XI.
Table XI. Vanadium in Cracking Catalyst
Sample Number No. of Determinations ppmV SStdDev
1 3 9.66 - + 33.5
2 5 24.10 - + 5.77
(J. Brownlee)
0 6 m s n " t lo-! lov I 10
MICROGRAMS OF VANADIUM
Blgure 21. Calibration curve for vanadium in cracking catalyst.
E. Activation' Analysis of Niobium
There is some apparent interest at the present time in analysis
for trace amounts of niobium in geological materials. Methods in
common use today for niobium determinations do not appear to be
capable of the high sensitivity found for many elements in the method
of analysis by activation. In view of this high sensitivity, an
attempt has been initiated to determine niobium by means of the
activity induced on neutron bombardment, that of the 4.2-minute
~b~~~ Isomer.
A solution of niobium carrier in dilute hydrofluoric acid was
irradiated for fifteen minutes in the pneumatic tube, and its spectrum
recorded. On comparing the observed photopeak with the barium K
X-ray (32 kev), it was found tha t the peak did not have an energy of
42 kev, as might be expected from its decay scheme ( ~ i g . 22), but
I'
DECAY SCHEME OF Nb 94 m
94m Figure 22. Decay scheme f o r N b .
had instead an energy of 16.8 - + 0.7 kev ( ~ i g . 23). Several determin-
a t ions of the ha l f - l i f e of t h i s peak were made, the average value of
which was found t o be 6.5 + 0.2 minutes. I r radia t ion of two dif ferent
niobium compounds confirmed tha t the photopeak recorded was tha t of
niobium having a 6.6 minute ha l f - l i fe . It is known (11) that the
.c:qpvepw%aq coefr&c.i=g,$ of- ;@94m :$B( &ng; as a. repu,$t of %he above ifi~*ej&&ggedm, 1% 16 p.os$u&$$c$d em$ SKe convegezoh d ~ W . p l c ~ g n t 18
., ; ~q $,&Be ~ m $ 42-key 9- Ppqn ;$vomeric t m s l t i t o n 2s a$m~eb
I cempla:b*?y c,onvep& m. ewe:tp@g @a :x-.my. .. 1
!F& n l~b ium X-sa~r was obsesved b$ meana of a 3'' r 3" Naf('~1)
&~.g$t&.l, but the presence ~f ithe X-ray sugg%st@d use of an x-ray'
propo.&fonal ewiiter a deteceing medium. Thus a,.,s&biple of' i m d i a t e d niobium carp ie r solu$,i,on -8 +nalyae.d by mews of a
krypton-filled X-ray proportional counter (331, whose output was Pea
In to t he 100-channel analyzer. A double peak was observed ( ~ i g . 241, . which had the proper half - l i fe , but which did not lend i t8elP t o
quant i ta t ive determinations. In a l l subsequent work, the 3" x 3"
Figure 24. K X-ray spectrum of niobium taken with
X-ray proportional detector.
~a1(Tl) crystal was used, with a slightly higher than normal voltage
(ca. 1150 volts) applied to the photomultiplier tube.
The chemical separation of niobium has proven to be somewhat of
a problem. Most niobium separations involve precipitation of niobium
as the hydrated oxide, Nb 0 .XH20, or of the tannate complex, or by 2 5
solvent extraction. The precipitation reactions lead to precipitates
which are too finely divided to allow rapid filtration, while the
solvent extraction procedures did not appear to give adequate
separations in a short time. A method of separating radio-zirconium
and niobium from fission products by adsorption on silica gel and
filter aids was found ( j 4 ) , and seemed to offer some possibility
f o r a c lean sepa ra t ion of niobium. It was found t h a t 75 percent of
N'bg5 t r a c e r could be adsorbed onto 0.5 gram of commercial s i l i c a
g e l by b o i l i n g a mixture of n i t r i c ac id , tJbg5 t r a c e r and s i l i c a g e l
f o r one minute and f i l t e r i n g . In view of t h e l a c k of o t h e r s u i t a b l e
methods t h i s method has been adopted, and i s under development. . .
A f i n e l y ground sample of r u t i l e , which i s pr lmari l 'y t i t an ium
dioxide, wi th small amounts of niobium and vanadium oxides , i s . .
a c t i v a t e d In t h e pneumatic tube f o r f i f t e e n minutes. The i r r a d i a t e d
sample, enclosed i n a g e l a t i n e capsule i s then fused .wi th 3-4 grams
of sodium peroxide, t h e melt cooled r ap id ly , and d isso lved i n d i l u t e
n i t r i c a c i d . The s o l u t i o n i s f i l t e r e d t o remove any undissolved
m a t e r i a l . Concentrated n i t r i c a c i d i s added t o t h e f i l t r a t e ,
followed by 0 .5 gram of s i l i c a g e l , and bo i l ed f o r one minute. The
s o l u t i o n i s f i l t e r e d through a medium s t a i n l e s s s t e e l f i l t e r funne l ,
t h e s i l i c a g e l d r i e d wi th acetone, and analyzed wi th t h e 100-channel
ana lyzer . Chemical recovery w a s 30-35 percent , determined by means
of N'bg5. A more d e t a i l e d o u t l i n e of t h e procedure i s given i n t h e
l a t e r s e c t i o n on Separat ion Procedures.
Analysis of t h e spec t r a showed a l a r g e amount of t i t an ium
contamination t o be presen t on t h e s i l i c a g e l . It appears , however,
t h a t t h i s contamination o f f e r s no s e r i o u s i n t e r f e r e n c e t o t h e niobium
determinat ion s i n c e t h e niobium X-ray photopeak i s s o f a r below t h a t
of t i t an ium. Prel iminary r e s u l t s show t h a t niobium i n amounts as . . .
low a s micrograms can be determined fol lowing t h i s t e n minute
s epa ra t ion . (J. ~ r o w n l e e ) . ,
F. A c t i v a t i o n Ana lys i s of Gold i n Marine Organisms e . . . . ..
I n ' t h e p r e s e n t work t h e a c t i v a t i o n a n a l y s i s of g o l d i n marine
b i o l o g i c a l a s h e s has been s t u d i e d by u s i n g a s imple chemical procedure
and y-spect rometry .
1. Pre l iminary Experiments . ..
In o r d e r t o work o u t t h e procedure f o r t h e radiochemical .
s e p a r a t i o n of go ld , t h e f o l l o w i n g p r e l i m i n a r y exper iments were
c a r r i e d o u t by ' u s ing A u lg8 t r a c e r .
a ) ~ x t r a c t i o n of g o l d from aqua r e g i a s o l u t i o n w i t h e t h y l a c e t a t e .
Condi t ion: 30 m l of aqua r e g i a i o l u t i b n of A U ( i n c l u d i n g -10 mg
A u c a r r i e r )
30 m l of e t h y l a c e t a t e
1 min. shak ing A u e x t r a c t e d 99%
3 min. shak ing Au e x t r a c t e d 98% . . , ,
b ) Back-extrac t ion of g o l d from e t h y l a c e t a t e l a y e r w i t h
ammonium hydroxide .
Condi t ion: -30 m l of e t h y l a c e t a t e l a y e r ( i n c l u d i n g e x t r a c t e d A u )
1 min. shak ing
2 min. shak ing
Au back-ex t rac ted 96% . .
Au back-ex t rac ted 97%
c ) P r e c i p i t a t i o n o f ' Au-metal from 1 - M HC1 s o l u t i o n by ' r educ t ion s .
w i t h SO2 g a s
-30 ml of I - M H C ~ solution of A U
5 min. bubbl ing (so2 g a s ) AU ' recovered 95.7% %
1 0 min. bubb l ing (so2 g a s ) Au recovered 98.1%
15 min. bubb l ing (so2 g a s ) Au recovered 99.2%
20 min. bubbl ing (so2 g a s ) Au recovered 99.2%
On t h e b a s i s of t h e s e d a t a , t h e procedures f o r . . < . .:":', ::,
s e p a r a t i o n have been a r r a n g e d ( c f . s h e e t s f o r Chemical s e p a r a t i o n s ) . ,<: .
2 . A n a l y t i c a l Procedure
About 500 mg of b i o l o g i c a l a s h were sealed i n po lye thy lene
t u b i n g , each of which was covered by 5 m i l A l - f o i l f o r p r o t e c t i o n
i n c a s e t h e p l a s t i c t u b i n g d i s i n t e g r a t e d i n t h e " i n pool"
i r r a d i a t i o n . The s t a n d a r d s were made by p i p e t t i n g a known , .
volume (101->OX) of go ld s t a n d a r d s o l u t i o n on t o a small p i e c e .
of f i l t e r paper of good q u a l i t y (15 rnrn d i a m e t e r ) and by e v a p o r a t i n g
t o d ryness . Each f i l t e r paper was s e a l e d i n p l a s ' t i c and prote-c ted
i n a way s i m i l a r t o ' t h e samples. The amount of Au i n s t a n d a r d s
ranged from 7 x t o 2.4 x 1 0 - ~ ~ .
A l l of t h e samples and s t a n d a r d s ( 6 samples and 6 s t a n d a r d s )
were p laced i n t h e same po lye thy lene b o t t l e w i t h Pb-metal as a
weight . The b o t t l e was p laced i n c o n t a c t w i t h t h e s u r f a c e of
t h e r e a c t o r - c o r e i n t h e r e a c t o r pool and i r r a d i a t e d f o r 1 4 . 1 hours .
After t h e i r r a d i a t i o n t h e samples w e r e q u i t e r a d i o a c t i v e
( p o s s i b l y - 2 .5 r / h r f o r t h e whole b o t t l e ) . Then t h e samples
were a l lowed t o s t a n d f o r abou t 5 days t o e l i m i n a t e e x t r a - a c t l v i i t e s .
A f t e r t h e c o o l i n g pe r iod t h e chemical s e p a r a t i o n of g o l d by
e x t r a c t i o n w i t h e t h y l a c e t a t e fo l lowed by p r e c i p i t a t i o n w i t h
SO2 g a s was c a r r i e d o u t a s o u t l i n e d i n t h e s e c t i o n f o r Chemical
S e p a r a t i o n s .
The s e p a r a t e d g o l d was counted f o r 5 - 1 0 minutes on t h e
O - 1 . 0 Mov rangc of the 100-cllannt.1 arlalyzer w i t h t h e 3" x 3"
c r y s t a l . The photopeak of t h e 0 .41 Mev y-ray of ~u~~~ was used
i n t h e a n a l y s i s .
. . .. . . - . > ?
3 . F l u x Monitor .,, . , , . .' :..- , ..
F i v e t o 1 0 mg of A1-Co f o i l s c o n t a i n i n g 0.356% Co.were ' ,.
a t t a c h e d t o b o t h s i d e s of each c o n t a i n e r ' o f samples and s t a n d a r d s . . .
60 After t h e induced a c t i v i t y of A 1 d i e d o u t , t h e long- l ived Co, . .
was counted d i r e c t l y w i t h t h e 100-channel a n a l y z e r . From t h e , . .
' count ing d a t a o b t . a i n e d . t h e ayeraged neu t ron f l u x f o r each sample
and s t a n d a r d was c a l c u l a t e d . In t h e computat ion t h e c o n t r i b u t i o n
of co60m a c t i v i t y t o co60 a c t i v i t y was cons ide red .
On an average , t h e the rmal neu t ron f l u x of 2 . 5 x 1012 n -2 -1 cm s e c was o b t a i n e d f o r t h e s e " i n pool" i r r a d i a t i o n s .
4 . C a l i b r a t i o n Curve . .
The c a l i b r a t i o n curve g iven i n F i g . 25 was c o n s t r u c t e d on
0.001 0.01 ' 0.1 1.0 MICROGRAMS OF COLD
F i g u r e 25. C a l i b r a t i o n curve f o r g o l d ( b i o l o g i c a l a s h ) ..
t h e bas io o f ' t h e da ta obtained f o r t h e s tandards a f . t e r processing
through a s i m i l a r chemical procedure t o 'that used f o r . t h e .samples.
~ c t . i v i t i e s p l o t t e d i n t h e f i g u r e were those normall-zed t o 10
- 2 . , -1: hours i r r a d i a t i o n a t . a neutron fKuX of 1 x 1012 n cm sec
wi th co r r ec t ions . f o r decay and chemical y i e l d . , . . . . .. . . .
5. R e s u l t s Obtained . .
Sample Sample W t . used A u ppm i n Ash mg
Ulva sp . (seaweed) 493 5 0 093 Col lected a t Enoshina', Sagami e y i n May, 1956
Ulva sp . (seaweed) 496.8 0.015 C o l l e c t e d a t Urayasu,
Tokyo Bay i n May, 1956
Mackerel (meat ) 495 5 0.003
I C l a m (meat) 503 2 0 ..079 . .
Shrimp (meat) 500.1 0.005
6. Notes
In t h e course of s t anda rd i za t ion more a c t i v i t y was obtained . . .
f o r t h e known amount of gold i n t h e s tandards than was expected.
This might poss ib ly be explained by t h e resonance e f f e c t s of
f a s t neutrons i n t h e formation of The lower l i m i t of
q u a n t i t a t i v e determinat ion a t t h e normalized cond1,tion s t a t e d
above (10 hours i r r a d i a t i o n a t t h e n e u t r o n f l u x o f 1 x 1012 n .
sec- I ) has been est imated t o be around 5 x g of A u
p resen t ( inc lud ing chemical s epa ra t ion ) when t h e cool ing per iod
f o r one"ha1f- l i fe i s taken i n t o cons idera t ion .
The probable e r r o r of the , whole a n a l y t i c a l procedure n e a t
I t h e lower l i m i t of determinat ion may be - - . + 50%. The e r r o r
of t h e ana lyses performed f o r t h e ;samples here may be ' _. + .30$ _. . ,
. . . or less. . (R. . Fuka i ) . . . . . . . . . .
. . . , . . . . . . , . . - . . . . . . , . ,
,. G Activatidi.1 Analysis ' of Rhenium i n Marine Organisms. . , . . ,
. .
1 n ' t h e presen t wdrk t h e a c t i v a t i o n a n a l y s i s o f , rhenium has been
s tud ied by using so lven t e x t r a c t i o n of rhenium wi th te t raphenyl : ,
.arsonium ch lo r ide and chloroform f.ollowed by y-spectrometry. . .
~ h e n i u m has t h e fol lowing two s t a b l e i so topes :
Re 185 - Abundance: 37.07%; Act. c ros s section' : 100 - + 20 barns
Re 187 - Abundance: 62.93%; Act. c ros s s ec t ion : 75 + '15 barns
By neutron cap ture of t hese s t a b l e i so topes , t h r e e ' r a d i o a c t i v e
! . %sotopes which a r e s u i t a b l e f o r t h e a c t i v a t i o n a n a l y s i s should b e ' ' '
produced. These a r e :
Re 186 - Half - l i fe : : 88.9 hours; Main y-ray: 0.137 Mev (22sj.. . :
Re 188 - Hal f - l i f e : 16.7 hours; Main y-ray: 0.155 ~ e v ( 2 ~ ) . .
. . Re 188m- H a l f - l i f e : -20 min. ; Main y-ray: 0.0635 Mev . .
In t h e presen t work, t h e y-ray peak of was used f o r y -
spectrometry. A t t h e same time, t h e p o s s i b i l i t y of u t i l i z i n g R e 1 8 8 m
f o r a c t i v a t i o n a n a l y s i s has a l s o been considered.
1. ~ n a l ~ t l c a l Procedure
About 500 mg of b i o l o g i c a l ash-were placed i n t o h i g h . p u r i t y , '
aluminum tubing (28 mm diameter, 5 m i l s w i l l t h i ckness ) and 'both '..
ends. of t h e tub ing were squeezed t i g h t l y by a l abo ra to ry press .-'. .
(1000 lb/ inch2) . The f i l t e r s tandards were prepared i n . . .
a way s i m i l a r t o t h a t f o r gold. The amount of R e i n ' s t a n d a r d s
8 ranged from 1 x t o 6 x 1 0 - g.. . . . .
. .
, . . .
A l l of t h e samples and s t a n d a r d s ( 5 samples and 6 s t a n d a r d s )
were p laced i n an aluminum can having w a l l t h i c k n e s s of 1/2 inch .
The can was i n s e r t e d i n t o t h e f i r s t row of e lements i n t h e
r e a c t o r - c o r e and a l lowed t o s t a n d f o r 11.5 hours f o r t h e
i r r a d i a t i o n . The samples were cooled f o r 6 days b e f o r e t h e
chemical procedure was c a r r i e d o u t . Samples were opened i n a
l e a d - s h i e l d e d box. A t t h e t ime of opening t h e sample, doses of
100-500 mr/h f o r l3-ray and -3 m r / h f o r y-ray were observed f o r
. each sample . After c a r r y i n g o u t a chemical s e p a r a t i o n based on e x t r a c t i o n
w i t h t e t rapheny la r son ium c h l o r i d e as o u t l i n e d i n t h e s e c t i o n
f o r Chemical S e p a r a t i o n s , t h e s e p a r a t e d rhenium was counted
f o r 5-10 min on t h e 0-0.5 Mev range of t h e 100-channel a n a l y z e r
w i t h t h e 3" x 3" y c r y s t a l . The photopeak of t h e 0.137 Mev
y-ray of I3ela8 was used i n t h e a n a l y s i s .
2. F l u x Monitor and C a l i b r a t i o n Curve ,
About 5 mg f o f l s of Al-do were used as f l u x moni to r s . Each
f o i l w a s s e a l e d i n a c l e a n po lye thy lene envelope and i n s e r t e d
w i t h t h e ash-samples and s t a n d a r d s . After t'he i r r a d i a t i o n , t h e
a c t i v i t y of co60 was counted a n d t h e f l u x was computed i n a
way similar t o t h e c a s e of Au-analysis . On an average , a 1 2 - 1
thermal neu t ron f l u x of 3 .5 x 1 0 n cm-2 sec was ob ta ined .
. From t h e coun t ing d a t a ' f o r s t a n d a r d s and t h e d a t a of f l u x
monitor.lng t h e normal ized a c t i v i t i e s f o r 1 0 hours i r r a d i a t i o n -2 a t t h e neu t ron f l u x of 1 x 1012 n cm oea-' were computed and
p l o t t e d v e r s u s rhenium c o n t e n t as g iven i n F i g . 26.
Figure 26. C a l i b r a t i o n curve fo r . r hen ium ( b i o l o g i c a l a s h ) .
3. Resu l t s Obtained
In t h e s p e c t r a of t h r e e samples .ou t of f i v e t h e rhenium-
peak i n ques t ion was found. Resu l t s obta ined a r e summarized
a s fo l lows :
Sample . Sample W t . used Re ppm i n Ash mg.
Ulva sp . (seaweed) -Co l l ec t ed a t Enoshima, Sagami Bay i n May, 1956
Ulva sp . (seaweed) 3 l l e c t e d a t Urayasu,
Tokyo Bay i n Q y , 1956
Mackerel (meat ) 503 9 < 0.008
C l a m (meat) 497.7 0.064 . ,
Shrimp (meat ) 498.9 < 0.005
4 Notes - From the calibration curve the lower limit of quantitative
determination at the normalized condition (10 hours irradiation . at the neutron flux of 1 x lo1* n sec-l) has been estimated
to be 1 x lo-' g of Re present (including chemical separation)
after the cooling period of one half-life.
On the other hand, the possibility of applying the short-lived
rhenium isotope el^'^) to the activation analysis seems to be promising. Figs. 27 and 28 show the y-peak of .0635 Mev of
Re 188m and the decay of this isotope respectively.. A half-life
of 20.6 minutes has been obtained for Re 188m in these experiments.
CHANNEL NUMBER
188m Figure 27. Spectrum of 63.5 kev gamma peak of Re . - - - 1 ' , . . - , c I&+-.+'.; 8 - ' ,1'~T:,p,,i12,1~p,-r,I$1 -, ; I I L 8 8 . 8 , :.
- , - , - 7 . , ,-;. ,,$; . = g rr . . rr....r 1 ' ' , '. -;I . , . . - , 8 . A - . '. .,I- -.. 8 - - . .. . . .; . . .:
L, .. , ,!i2, . ,..- . ~ . . 'I- 1.' 8 ' : . .
8. Decay cumres of Re 188111
This value does.not agree with the value of 18-17 minutes . and .. ' '
22 minutes which have .been.reported. At any rate, since . * . .. . . . the
utilization of the'short-lived rhenlum isotope for the.activation
analysis should decrease the formation of the extra-activities
in the samples, the chemical separation procedures may be carried : L
out much more easily than when using the long-lived isotope.
The.lower limit of quantitative determination at the normalized
conditions (10 min 'irradiation at-the neutron flux of 1 x 10 12
- 2 8 n cm sec-l) should be around 1 x 10- g of rhenium present.
The probable error for the activation analysis of rhenium .
by using the long-lived isotope (Re 186) around the lower limit
of determination stated above (1 x lo-' g Re) is estimated to
be around - + 35%. The errors included in the present analyses may be estimated
to be less than'+ - 25S.except for the negative results. (R. ~ukai)
H. Activation Analysis of Molybdenum in Marine Organisms, '
The activation analysis of molybdenum by means of y-spectrometry
has been accomplished by using Tclol activity. ' This procedure has
been based on the following nuclear reaction:
MO'OO (n, y) MO"' 14.b f3- min. Tclol @- 14.0 min. Rulol (stable )
(Abundance: 9.62$, Cross Section 0.5 barns)
By separating TC'" from other isotopes and by counting the
' T C ~ O ~ activity, the amount of molybdenum originally present cou,ld
' be estimated. For the-chemicab separation of technekl~~rn a method
similar to the separation for rhenium can be used. The chemical
78 ;
s e p a r a t i o n of technet ium by us ing t e t r a p h e n y l arsonium c h l o r i d e a s
a complexing agent ' seems k o r e s p e c i y i c thah 'any separ&t3di-"procedure
f o r molybdenum. I n a d d i t i o n t o t h i s , ' 'it 'is n o t n e c e s s a r y t o d i s s o l v e . . . . .
t h e sample r a p i d l y s i n c e t h e T C - a c t i v i t y grows u n t i l 15 min. ' a f t e r
t h e i r r a d i a t i o n .
J?ig. 29 shows a n example of a h i r r a d i a t k d M& s p e c t r a ' i n which
b o t h Mo'and Tc peaks a p p e a r s i d e by s i d e . ' ~ i ~ . 30 i l l u s t r a t e s t h e
d e c a y of t h e Molol peak and t h e growth a n d . decay of t h e Tclol peak
a p p e a r i n g i n the ' p rev ious f i g u r e .
1 .. A n a l y t i c a l Procedure . . .. .
Between 200 and 250 mg of b i o l o g i c a l a s h were s e a l e d i n
po lye thy lene t u b i n g . . and i r r a d i a t e d f o r 15 minutes i n pneumatic
t u b e No. 3 u s i n g t h e quick-opening r a b b i t . Immediately a f t e r
0 l I I I I 1 I 0 10 20 30 40 50 60
CHANNEL NUMBER
F i g u r e 2 9 . Gamma s p e c t r a of MO'O' and TC'O' a f t e r 1 0 minute i r r a d i a t i o n .
c h l o r i d e s e p a r a t i o n o u t l i n e d i n t h e s e c t i o n on Chemical S e p a r a t i o n s
was made. The s e p a r a t e d TC'O' a c t i v i t y was counted i n t h e 100-
channel ?-analyzer w i t h 3" x 3" c r y s t a l . The decay o f ' t h e
TC''' peak (0.307 Mev. ) w a s fo l lowed f o r 1 0 minutes by r e c y c l i n g
t h e count every 1 minute. The coun t s o b t a i n e d f o r every 1
minute were p l o t t e d v e r s u s t i m e on semi - logar i thmic g raphs and
t h e a c t i v i t y a t 15 minutes from t h e end of t h e i r r a d i a t i o n was
estimated by e x t r a p o l a t i n g back t h e s t l -a igh ' t l i n e t o t h e t ime
i n q u e s t i o n . By comparing t h i s , a c t i v i t y w i t h t h o s e o b t a i n e d
f o r s t a n d a r d s p rocessed under iden t i c , a l . coridit'i'ons. t h e molybdenum _ .' I . .. .
c o n t e n t of samples was estffiat.ed' .
2 . ' F l u x Monitor and c a l i b r a t i o n Curve . . ..A :
Gold f o i l s were used a s ' t h e ' f l u x moni tor . F o r 13 i r r a d i a t i o n s
-2 i n 3 days the, average f l u x of 9 .4 x 1011 n cm s e c - I was. . .
o b t a i n e d .
The c a l i b r a t i o n curve f o r molybdenum d e t e r m i n a t i o n s shown
i n F i g . 31 was. cons t ruc ted . .on t h e b a s i s of t h e coun t ing d a t a
. , MICROGRAMS OF MOLYBDENUM .
~ i ~ u ' r e 31. C a l i b r a t i o n curve f o r molybdenum ( b i o l o g i c a l a s h ) . f o r s t a n d a r d s and t h e d a t a o f ' f l u x moni torfng. ' The a c t i v i t y . a
.
p l o t t e d i n t h e f i g u r e was normal ized f o r 15 minutes i r r a d i a t i o n -2 . .
a t a neu t ron f l u x of 1 x lo1? n c m sec-I . and %15 minu te 'g rowth .
3. Results Obtained and Notes . ' . '~i., .
Three samples of seaweed were analyzed. Among these I
I - molybdenum was only determined for one sample. This fact
suggests that the sensitivity of the method used was not
sufficient to determine the minute quantity of mol.ybdenum
present in marine organisms. The results.obtained were
summarized as follows:
Sample
Ulva sp. (seaweed) T l l e c t e d at Enoshima, ' Sagami ~ a y in m y , 1956
Ulva sp. (seaweed) T l l e c t e d at Urayasu, Tokyo Bay in May, 1956
Por h ra sp. (seaweed) *ted at Chiba, Tokyo Bay in Jan., 1957.
Sample Wt. used Mo ppm in Ash ' m!3
254.9 Not detected
250.4 Not detected
These data suggest that there is a tendency to find high , . ' !
molybdenum content in seaweed having high vanadium content.:. . . ; '
The lower limit of quantitative determination at the
normalized condition (15 minutes irradiation at the neutron flux -2
of 1 x 1012 n cm sec-l) should be around 5 x loe7' g of
molybdenum present (including chemical separation).
The sensitivity may be increased by using the long-lived
isotope of molybdenum (67-hour MO" from l"Iog8: abundance 23.75$,
cross section 0.4 barns), but not too much.
The probable error expected for the analysis in the vicinity
of the lower limit of determination may be around - + 35%. (K. ~ukai)
I. A c t i v a t i o n Ana lys i s of Tungsten i n Marine Organisms,. . . . .:., ..:
.. . The a c t i v a t i o n a n a l y s i s of t u n g s t e n has been s t u d i e d by us ing
s o l v e n t e x t r a c t i o n of t u n g s t e n and y-spect rometry . Tungsten has
many s t a b l e . i s o t o p e s shown below.
Abundance Act. c r o s s s e c t i o n
0 135% 60 - + 60 b a r n s
26 .4 $I 1 9 - + 2 b a r n s
1 4 . 4 $ 11 - + 1 barns
30.6 $ 20 - + 0 . 3 ba rns
28.4 $ 34 - + 3 b a r n s
However, among t h e s e o n l y one i s o t o p e seems t o be s u i t a b l e f o r
a c t i v a t i o n a n a l y s i s . w~~~ has a f a i r l y l a r g e abundance and a good
a c t i v a t i o n c r o s s s e c t i o n , s o t h a t it should be e a s y t o u t i l i z e t h e
T h i s i s o t o p e has a h a l f - l i f e of 24 hours and a decay scheme
i l l u s t r a t e d below.
~ e " l (stable)
A l l of. .the,se: 7 y-rays,were. pbserved i n a spec t rum. taken f o r '
i r r a d i a t e d tungsten. An example- of , s p e c t r a i n t h e 0 . - 1..!0 Mev. range
is given i n F ig . .32. . . .
0 l I I I I I I I 1 0 CHANNEL NUM8ER
80
Figure 32. Gamma s p e c t r a of tungsten a f t e r 6 .3 hours i r r a d i a t i o n .
For t h e determinat ion of tungsten by y-spectrometry t h e y-ray
of 0.072 Mev was mainly used.
1. Analy t ica l Procedure
About 500 m g of b i o l o g i c a l a s h were 'sealed i n polyethylene
tub ing . The f i l t e r paper ' s tandards were prepared i n a way ..
s i m i l a r t o t h a t of gold. The amount of tungsten In t h e -6 s tandards ranged from 5 x loe8 g t o 1 x 10 g.
F i v e samples and f i v e standards! 'were p laced t o g e t h e r i n
a n aluminum can i n a manner similar t o t h a t used ' i n t h e '
i r r a d i a t i o n of rhenium samples. Then t h e samples a n d , s t a n d a r d s ' -
were i r r a d i a t e d f o r 6.3 hours i n t h e f i r s t row of t h e r e a c t o r
c o r e .
A f t e r t h e c o o l i n g p e r i o d of 48 hours t h e chemical s e p a r a t i o n
of t u n g s t e n was c a r r , i e d o u t u s i n g a thiocyanate-ethyl'acetate
e x t r a c t i o n as o u t l i n e d i n t h e s e c t i o n on Chemical s e p a r a t i o n s .
Separa ted t u n g s t e n w a s counted f o r 5 minutes i n t h e 100-channel
y -ana lyzer by u s i n g t h e 0-0.25 Mev range. The photopeak o f ' t h e
0.072 Mev y-ray of dB7 was used i n t h e a n a l y s i s . .
2 . F l u x Monitor and c a l i b r a t i o n Curve
The f l u x moni tor ing was done i n a manner similar t o t h a t
of t h e rhenium d e t e r m i n a t i o n . An average . f l u x of 1 .52 x 1 0 1 2
- 2 n cm s e c - I was ob ta ined . . ' , ...
From t h e coun t ing d a t a f o r s t a n d a r d s and t h e d a t a of f l u x
moni to r ing t h e normal ized a c t i v i t i e s f o r 10 hours i r r a d i a t i o n -1 a t t h e n e u t r o n f l u x of 1 x 1012 n s e c were computed and
p l o t t e d v e r s u s t u n g s t e n c o n t e n t a s g iven i n F i g . 33.
3 . R e s u l t s Obtained
Among t h e f i v e s p e c t r a o b t a i n e d f o r samples, c h a r a c t e r i s t i c .
y-peaks f o r t u n g s t e n were found i n t h r e e of t h e s e . R e s u l t s
obta. ined are summarized as f o l l o w s :.
Sample . : S a m p l e W t . used W p p m i n Ash mg
.. ,
Ulva s p . (seaweed) 497. 3 0.13 C o l l e c t e d a t Enoshima, , . .
.Sagami m y i n m y , 1956
MICROGRAMS OF TUNGSTEN
Figure 33. Cal ibra t ion curve fir tungsten (b io log ica l a s h ) .
Sample Sample W t . used . W ppm-in Ash mg- .
Ulva sp . (seaweed) 497 7 .0.18 T l l e c t e d a t Urayasu,
Tokyo Bay. i n May, ,1956
Mackerel (meat.) .- 502 5 < 0.014
Clam (meat) . . 504.6 0.46
Shrimp (meat) . , 505.0 (0.005
From the c a l i b r a t i o n curve t h e lower l i m i t of q u a n t i t a t i v e
determination a t t h e normalized condition (10 hours i r r a d i a t i o n
. . . ' . -2" a t t h e neu t ron f l u x of 1 x 1012 n cm s e c - l ) shou ld be around
5 x lo-' g of t u n g s t e n a f t e r t h e c o o l i n g p e r i o d . . . of one h a l f - l i f e
( i n c l u d i n g chemical s e p a r a t i o n ) .
A p robab le e r r o r between - + 40 and - + 50% may be expected
f o r t h e v a l u e s o b t a i n e d around t h e lower l i m i t of d e t e r m i n a t i o n .
, I n t h e p r e s e n t d e t e r m i n a t i o n s t h e e r r o r s may be w i t h i n - + 20s except
f o r n e g a t i v e r e s u l t s . ( R . ~ u k a i )
J. A c t i v a t i o n Ana lys i s of Cobal t i n ~ l u m i n u m - c o b a l t ' F o i l
F o r t h e l o n g p e r i o d i r r a d i a t i o n s ( > 3 h o u r s ) aluminum-cobalt
f o i l has u s u a l l y been used as a f l u x moni tor . In t h e computat ions
of neu t ron f l u x from t h e a c t i v i t i e s induced i n aluminum-cobalt f o i l ,
i t i s e s s e n t i a l t o know t h e c o b a l t c o n t e n t of t h e f o i l .
In t h e p r e s e n t work t h e a c t i v a t i o n a n a l y s i s of c o b a l t i n aluminum-
c o b a l t f o i l h a s been c a r r i e d o u t . b y .y;spectrometry wi thou t chemis t ry ,
i n o r d e r t o o b t a i n b a s i c d a t a f o r t h e f l u x moni tor .
1. A n a l y t i c a l Procedure
Three p i e c e s of aluminum-cobalt f o i l having weights r ang ing
from 1.3 t o 1 . 9 rng were i r r a d i a t e d f o r abou t 2 minutes i n
pneumatic t u b e No. 3. A f t e r t h e i r r a d i a t i o n t h e samples were
cooled f o r 30 minutes t o e l i m i n a t e t h e induced a c t i v i t y of
aluminum (2 .3 minute h a l f - l i f e ) , and t h e a c t i v i t y of f o i l samples '
was c o u n t e d d i r e c t l y by t h e 100-channel y -ana lyzer w i t h 3" x 3"
c r y s t a l . The decay of t h e co60m peak (0.059 M ~ V , 1 0 . 5 minute
h a l f - l i f e ) was fol lowed f o r 1 0 minutes by r e c y c l i n g t h e count'
eve ry 1 minute . The coun t s o b t a i n e d f o r every 1 minute were
' p l o t t e d v e r s u s t ime on semi- logar i thmic graphs and ' t h e i n i t i a l
a c t i v i t y of each sample was e s t i m a t e d by e x t r a p o l a t i n g back
t h e s t r a i g h t l i n e , to z e r o t i m e .
2. C a l i b r a t i o n and F lux Monitor .-
Standard s o l u t i o n s of c o b a l t were prepared by d i s s o l v i n g
CO(NO ) *6H20 i n water. The s t a n d a r d s of c o b a l t were made by 3 2
p i p e t t i n g o f f t h e known volume (10-301) of c o b a l t s t a n d a r d
s o l u t i o n s o n t o t h e small f i l t e r paper ,of good q u a l . i t y (15 mm
d i a m e t e r ) and by e v a p o r a t i n g o f f t h e s o l u t i o n . The range of
c o b a l t c o n t e n t of s t a n d a r d s was from 1 x g t o 1 x g
c o b a l t . The s t a n d a r d s were i r r a d i a t e d i n a way similar t o t h e
samples, w h i l e t h e coun t ing was s t a r t e d from 2 minutes a f t e r
t h e i r r a d i a t i o n . From t h e data o b t a i n e d f o r s t a n d a r d s t h e
c a l i b r a t i o n curve g i v e n I n F i g . 34 was drawn. A c t i v i t i e s p l o t t e d
i n t h e f i g u r e were t h e e s t i m a t e d i n i t i a l a c t i v i t i e s normal ized -2 -1 f o r 2 minute i r r a d i a t i o n a t t h e neu t ron f l u x of 1 x 1012 n cm s e c .
I- / 2 MINUTE IRRADIATION AT THERMAL NEUTRON FLUX OF I xl0' N CM-' SEC-'
101 1 1 1 1 1 1 1 1 I I 1 1 1 , 1 1 1 I 1 1 1 1 1 1 1
0.01 0. I 1 .o 10 MICROGRAM OF COBALT
F i g u r e 34. C a l i b r a t i o n curve f o r c o b a l t .
For moni tor ing t h e neu,tron , . . f l u x about 1 mg of . . g o l d - f o i l . . w a s . .. : ., 3,:
11 a t t a c h e d . t o each sample. . . On an average, a f l u x of 7 .5 x . l o . . . . . . ..
-2 - 1 n cm s e c was .obtained f o r i r r a d i a t i o n s .
3 . . Resu l t s ,Obtained and Notes I . .
~ e s u l t s ob ta ined :
Mate r ia l : A1-Co f o i l ( 2 m i l s t h i c k n e s s )
Sample W t . I r r a d i a t i o n Neutron Normalized Co-Content . , Time Flux A c t i v i t y f o r . .
(n c r 2 2 m n irf2d.: 53 C6 Fg (w) (min > sec-') 1x10 15 n cm sec co$
Three va lues ob ta ined f o r t h e same m a t e r i a l i n . s l i g h t l y
d i f f e r e n t cond i t i ons of i r r a d i a t i o n s showed good agreement w i th
each o t h e r .
However, s i n c e t h e s e va lues were ob ta ined wi thout cons ider ing --
t h e e f f e c t of s e l f - s h i e l d i n g by f o i l i t s e l f , t h e a c t u a l va lue may
I be 576 h i g h e r than t h e s e va lues . The e f f e c t of s e l f - s h i e l d i n g
I was eva lua ted by comparison of t h e a c t i v i t i e s ob ta ined f o r . ,
normal s t anda rds wi th . $hose ob ta ined f o r t h e s t anda rds covered
by A 1 f o i l dur ing i r r a d i a t i o n . (R. ~ u k a i )
K. Ac t i va t i on Analysis f o r Trace Elements i n Marine 0rgani.sms
I The work summarized p r ev ious ly (3 ) f o r vanadium and a r s e n i c has
been expanded t o i nc lude de te rmina t ions of molybdenum, tungs ten , . . , 1 . . . .-- . .
. . . . "::.,
rhenium and gold as described above.
Analyses were made on samples of ignited.marine organisms
representative of seaweeds, mollusks (without shell), crustaceans
(without carapace), fishes (soft parts) and sea water.
Table X I 1 summarizes the approximate sensitivities obtained for .
these different elements and lists information pertinent to the
chemical separations. The sensitivities listed are probably good to
within a factor of 2 and are given only as an indication of the
approximate limitations of the specific methods used. This is not
to imply that higher sensitivities are not possible with additional
improvements in the methods.
This work on the six elements is being summarized in a manuscript
which will be submitted soon for publication. (R. ~ukai)" .
L. Activation Analysis of Trace Cobalt, Vanadium and Copper in Tissue
There is considerable interest in analysis for trace elements
in tissue. Often standard techniques lack the sensitivity possible
with activation, analysis or, where they are as sensitive, are plagued
with. large "blank corrections" for traces of the unknown added during
the procedure. Thus it'has seemed worthwhile to explore the applica-
tion of activation analysis to typical tissues (rat liver and kidney)
utilizing the short-lived ~o~~ (10.5-minute), v~~ (3.7-minute) and cuP6 (5 .I-minute).
Tissue samples were air dried at room temperature for 24 hours,
then placed in envolopes prepared from 4 mil thick polyethylene film
which were closed by heat sealing. These sealed samples were then
irradiated in the rabbit system along with suitable monitoring foils.
Table XII. Approximate Experimental Sensitivities and Mode of Chemical Separation
for Six Trace ~lements in Marine Biological Ashes.
Vanadium Arsenic Molybdenum Tungsten Rhenium Gold
Experimental 2 lo-9*+ 5 x 10- 8 5 lo-'7 5 lo-9 I 10-9 5 x 1o-lo Sensitivity (10 min.irrad) (10 h.irrad) (15 min.irrad) (10 h.irrad) (10 h.irrad) (10 h.irrad)
(g * lux: 3 x 1012 n cm- sec-1)
Co-ppt with .(C H ) AsC1- thiocyanate- (C H ) AsC1- Ethyl Mode of Chemical Cupf erron- 6 5 4 6 5 4 - \D Separation chloroform phospho- Acetate 0
molybdate chlorof o m ethyl acetate chloroform Extraction
Chemical yield 90% -60% 60% 30% - 70% 80%
Time required for - 4 min. 30 min. 30 min. *** 40 min. 30 min. . 30 min. the separation
*The computation of sensitivity includes the cooling period of one half-life for long-lived isotopes of arsenic, tungsten, rhenium and gold, and the correction for the chemical yield.
**This value was estimated on the basis of counting with a y-scintillation well counter.
***The time includes the waiting period of 15 minutes.
The i r r a d i a t e d samples were then fused with sodium p e r o x i d e - i n a
n icke l c ruc ib le and the melt then subjected t o a r ap id radiochemical
separa t ion . For cobal t t h i s cons is ted of an 8-hydro~yq~uinol ine
e x t r a c t i o n and then p r e c i p i t a t i o n of cobal t as the oxide with Na202.
The vanadium was separated with a cupferron e x t r a c t i o n . The copper
was a l s o separa ted ' by a cup'f e r ron e x t r a c t i o n cycle and then 'pre-
c i p i t a t e d as the s u l f i d e . D e t a i l s of these procedures can be found /
i n the f i n a l s e c t i o n of t h i s r epor t on separa t ion procedures. The
radiochemical procedures f o r cobal t can be completed i n 1 5 minutes,
f o r vanadium i n 5 minutes and f o r copper i n 8 minutes.
A desc r ip t ion of Lhe work on the co60m w i l l appear i n an e a r l y
i s s u e of Talanta; manuscripts descr ib ing experiments on the o the r two
elements a r e being prepared. Experimental s e n s i t i v i t i e s obta inable
f o r these elements appear t o be about 5 x grams of cobal t ,
3 x lo-' grams of vanadium and 3 x .grams d f c o p p e r a t a f l u x of
-1 1012 n cmm2 sec . (D. Kaiser )
M . Prel iminary Inves t iga t ions of ( n , a ) , (n ,p ) , and (n ,y) as Competing Reactions i n Act ivat ion Analysis of Biological Tissue
The p o s s i b i l i t y of (n , a ) and (n ,p) r eac t ions i n t e r f e r i n g with ' 66 52 (n ,y) a c t i v a t i o n analyses was considered f o r C O ~ ~ , Cu , and V .
If t h e y i e l d s from these r eac t ions were appreciable , t h e q u a n t i t a t i v e
r e s u l t s of (n,y) procedures would be higher than expected. P r i o r t o
any experiments, rough ca lcu la t ions were made t o determine the ex-
pected a c t i v i t y from each of the r eac t ions . Assuming t h e s t a r t i n g
ma te r i a l s were present i n une gram amounts and the av.ailable neutron .- .
12 f luxes f o r (n ,y ) , ( n , ~ ) , and ( n , a ) r eac t ions were 1 x P O , 3.5 x
lo8, arid 7.1 x lo7 , r e spek t ive ly as repor ted previous ly f o r our
9 2
r e a c t o r ( 3 ) , t he fol lowing a c t i v i t i e s would be expected a able XIII).'.
Table X I I I : A c t i v i t i e s f o r Competing Reactions.
Reactions
60m 1. Co.
Calculated A c t i v i t i e s (d/m)
, Considering' t he r eac t ions i n order , t h e n a t u r a l n i cke l content . . . . - . . . . . .
of ' r a t kidneys i s too low t o o f f e r any complications by (n ,p)
r eac t ion . Copper would, be expected t o o f f e r the most in t e r f e rence
t o t h e ~ o 5 9 ( n , ~ ) ~ ~ ~ o ~ ~ r e a c t i o n i n b io log ica l t i s s u e . For the : '
27 (n ,a ) r e a c t i o n t o i n t e r f e r e , however, copper would have t o be present
i n r ; l a t ive ly l a r g e r q u a n t i t i e s than n a t u r a l l y occurs i n r a t kidneys.
This r e a c t i o n 'was checked by i r r a d i a t i n g 500 micrograms' b f . .
copper n i t r a t e i n a cadmium-lined r a b b i t ( see ~ i g u r e 35) . The sample
was i r r a d i a t e d f o r 30 minutes a t one megawatt and allowed t o decay
f o r 15 minute's p r i b r t o gamma s p e c t r a l ana lys i s . Without a chemical
. . .
Cd-20 MIL
SAMPLE SEALED IN POLYETHYLENE
Figure 35. Side view of cadmium-lined r a b b i t .
60m could . be observed. separa t ion , no Co . . ,
An (n ,p) r eac t ion on ~n~~ could o f f e r in t e r f e rence t o t h e
65 29
Cu (n, 'y) 2 g ~ ~ 6 6 reac t ion . Natura l ly occurr ing zinc i s present
i n amounts t h a t would cause l e s s than 1% v a r i a t i o n i n q u a n t i t a t i v e ,
~u~~ r e s u l t s . Gallium a l s o 'would not be expected t o i n t e r f e r e
because of low abundance.
A s a check on the competing r eac t ions i n the vanadium analys is ,
samples of,chromium n i t r a t e (-500 microgram's) and manganese dioxide
(-500 micrograms ) were i r r a d i a t e d i n the prevlous ly descr ibed
cadmium-lined r a b b i t (Figur'e 35) . Following a . ten-minute i r r a d i a t i o n
and five-minute decay, the gamma s p e c t r a exhib i ted a s m i l v~~ peak
(1.4 ~ e v ) . This v~~ peak was observable without a chemical separa t ion .
Excessive amounts of chromium and manganese thus could o f f e r
d i f f i c u l t i e s i n the t r a c e ana lys i s of vanadium. However, t h e
q u a n t i t i e s which occur i n normal r a t l i v e r s present no problems.
These experiments show t h a t when analyzing f o r t r a c e cons t i tuen t s
competing r eac t ions can present problems . . i n q u a n t i t a t i v e determina-
t i o n s . Generally these r eac t ions a r e . i n . l o w . y i e l d ... . because of the . . . , . . . .
r e l a t i v e l y few fast neutrons present compared t o thermal neutrons.
However, when the i n t e r f e r i n g elements a re present i n q u a n t i t i e s
g r e a t e r than l o 5 times t h a t of the t r a c e elements, t he (n,p) and . ~
(n ,a) reac t ions should be thoroughly inves t iga ted . (D. ~ a i s e r . )
N. Preliminary Inves t iga t ions of the Activat ion Analysis of Trace Selenium i n ~i-'~; ~ e ' ' ~ ~ , and setllm
During t h e course of inves t iga t ions conducted on selenous ac id ,
r a t l i v e r t i s s u e was i r r a d i a t e d t o determine the presence and.con-
c e n t r a t i o n of n a t u r a l l y occurr ing selenium. Rothstein (35) noted
t h a t "administered selenium i s d i s t r i b u t e d i n a l l s o f t t i s s u e s , but
i s e s p e c i a l l y high i n the l i v e r and kidneys ." Because of the unique
equipment ava i l ab le i n t h i s labora tory f o r work with shor t h a l f - l i v e s
i t w a s decided t o analyze f o r the 17-second isomer of selenium, i.e..,
~ e ~ ~ ~ . The samples could be i r r a d i a t e d f o r shor t periods of time
(-30 seconds), removed from t h e r eac to r , r ap id ly relayed t o the
counting a rea by an a u x i l i a r y " rabbi t" system (15-17 seconds), and
i d e n t i f i e d both q u a l i t a t i v e l y and q u a n t i t a t i v e l y with the 100-channel
analyzer .
F i r s t , varying concentrat ions of selenous ac id were i r r a d i a t e d
and the rapid t r a n s f e r procedure perfected. The 0.160 Mev gamma ray
was observed t o decay with a h a l f - l i f e of 16-17 seconds. This
procedure was per'formed without a chemical separa t ion . A l i v e r sample
was then i r r a d i a t e d i n an i d e n t i c a l manner and s i m i l a r r e s u l t s were
observed. A q u a n t i t a t i v e determination es t ab l i shed t h a t selenium , .
was present i n the order of 7 x gms/gm of f r e s h l i v e r t i s s u e .
. . I s o l a t i o n of selenium from t h i s t i s s u e v i a a chemical separa t ion
was considered the next s t e p f o r confirmation. The procedure described
by 3clilridewoif ( 3 ) was appl ied t o the r a t l i v e r s i n an attempt , t o . . .
iso1at.e the 3.9-minute ~ e ~ ~ ~ . . According t o t h e gamma-ray spectrum;
however, ~n~~ was the primary. a c t i v i t y obtained.
A second procedure was then developed as follows:
1. I r r a d i a t e sample 10 min. a t 1 megawatt.
2. Fuse sample , i n 10 &ms Na202 containing 20 me; selenium c a r r i e r .
3. Cool and d i s so lve melt i n 50 m l wat-.
4. Add 50 ml conc. H C 1 and h e i t so lu t ion t o , bo i l ing .
5. Bubble i n SO2 gas and pass through f i l t e r chimney.
6. Wash elemental selenium p r e c i p i t a t e with water.
7. Dissolve selenium i n hot 3 N K C 1 and p lace i n separa tory funnel'.
8. Add 10. ml 10% sodium potassium t a r t r a t e so lu t ion -and ad jus t pH t o a value between 7.5 and 12.5.
9 . Shake f o r 30 sec. with 1 0 m l 19 8-hydroxyquinoline i n C H C l 3' 10. Discard C H C l l a y e r and a c i d i f y aqueous l a y e r with 10 m l
conc. .HC1. 3
11. P r e c i p i t a t e elemental selenium with SO2 gas and' pass through f i l t e r chimney.
12. Determine a c t i v i t y with 100-channel analyzer .
This procedure requi red twenty minutes f o r completion and gave
a y i e l d of only 30% (based on recovery of ~ e ~ ~ ) but s p e c t r a l ana lys i s
of a processed rat, l i v e r sample showed t h a t only small amounts of
Mn56 contamination came along. Since t h i s 2 0 minute procedure was
q u i t e long f o r t h e 4-minute se7*, the separa t ion was appl ied t o
81m 57-minute Se . Following a one-hour i r r a d i a t i o n and thir ty-minute decay,
ca:I.culatione andicated t h a t ( I ) no de tec tab le a c t i v i t y would be
expected from 8e7', ~ e ~ ~ ~ , o r ~ e ~ ~ ~ , (2 ) de tec tab le amo,~nts of 8 . .
1 activity would be obtained from se81m, and (4) the activity from cc ;- - 1 seB1. w6uld be of little value in gamma scintillation spectrometry'.: - - ' ~ The procedure described for ~e~~~ was applied to se81m with negative.;:.
8 1 results. No attempts were made to analyze for Se .
It was concluded that trace selenium was present in rat liver
tissue but that the chemical separations utilized in thks brief
preliminary study were: (1) not too specific in this biological
system, (2) the chemical yields were not too satisfactory, and - ( 3 )
. .the processing time was too long.
0. Preliminary Investigations on (n,2n) Reactions for'bctivation
Analysis of Carbon, Nitrogen and Oxygen
1. Introduction
This study was initiated to investigate the possibilities
of using (n,2n) reactions to' analyze for carbon, nitrogen and
oxygen in biological systems. The familiar (n,y) reactions can
not be readily applied to these elements because of low isotopic
abundances, low thermal cross sections, or half-life considera-
tions. For example, carbon activation by an (n,y) reaction
would produce carbon-14. The low isotopic abundance (1.11%),
low thermal cross section (0.9 mb), aid long half-life (-5,600 y) ,
cause this reaction to be of very.10~ yield. Similar considera-
tions would seem to place nitrogen, and oxygen in the s h e
situation, but, by utilizing the "bunny rabbit" system and the
100-channel analyzer, it was possible to determine nitrogen-16
and oxygen-19. 'With half-lives of 7.4 seconds and 29 seconds,
respectively, little if any time could be allowed for a semi-
quantitative chemical separation prior to counting.
Tlie abundances of carbon-12, nitrogen-14 and oxygen-16 a r e
g r e a t e r than 98$. The half- l i .ves of the (n,2n) products range
between two and twenty minutes so t h a t s u f f i c i e n t time could be
a l l o t t e d f o r a apossible chemical separa t ion . Although the f a s t
neutron f l u x i n . t he Ford Nuclear Reactor pneumatic tubes was.
low, some i n d i c a t i o n of the procedure 's value could be obtained.
It was the purpose of t h i s prel iminary study t o i n v e s t i g a t e the
p o s s i b i l i t i e s of (n,2n) a c t i v a t i o n and determine the l.ower leve lo
of s e n s i t i v i t y without chemical separa t ions .
2. Procedure
The samples f o r ana lys i s were sea led i n polyethylene tubing
and then enclosed i n a cadmium envelope ( 2 l a y e r s of 10 m i l
cadmium meta l ) . Samples prepared i n t h i s manner were placed i n
polyethylene r a b b i t s and i r r a d i a t e d i n the pneumatic tube system
of the Ford Nuclear Reactor. Following a s u i t a b l e i r r a d i a t i o n
time, the samples were removed from the r e a c t o r and a l iquo t s of
the mater ia l taken f o r ana lys i s . Two samples were prepared,
one f o r gamma s p e c t r a l ana lys i s and the o the r f o r h a l f - l i f e
determinat ion by propor t ional counting. The decay curves were
resolved and a c t i v i t y versus weight graphs.prepared.
3. Resul t s
a . Carbon. This experiment was. conducted with a n a l y t i c a l
reagent benzene a s the source of carbon. The samples were
. i r r a d i a t e d f o r 10 minutes a t 1 Megawatt and allowed t o
decay f o r two minutes p r i o r t o . counting. The 6 ~ 1 2 ( n , 2 n ) 6 ~ 11
r e a c t i o n produceo a 20;5-minute 0.96 Mev posi t ron-emit t ing
i so tope . ' ~ l i ~ u o t s of t h e i r r a d i a t e d ma te r i a l were pipetted
onto f i l t e r paper and scotch-taped t o cardboard. counting
cards. A 0-4 Mev gamma spectral determination, performed
with the 100-channel analyzer, yielded the expected 0.511 Mev.
annihilation radiation peak. By integrating the area under. . ..:
this peak, a quantitative determination for 6~11 was . . . .
obtained. A graph of activity versus concentration of . . .
carbon .was prepared (Figure 36) from these data. Accepting .....
I00 counts per minute per peak area as the lower limit of
.detection, 8 x gms of carbon may be determined. Decay
of the samples was also followed by proportional counttng
as a cross-check on half-life.
b . . Nitrogen. Basically this procedure was the same as. f.or
carbon. Nitrogen-13, a 1.2 Mev positron-emitting isotope .
with a 10-minute half-life, may be produced by the
14 7 N (n, 2n)7~13 reaction. Samples of ammonium thiocyanate, ' ; .
sealed in polyethylene, were irradiated for five minutes - -
at 1 Megawatt and allowed to decay for two minutes prior to .
counting. The decay curves were resolved into their com-
ponents and the amount of nitrogen determined. .Again, two
s'amples were prepared, one for the. 100-channel analyzer and
the other for proportional counting.. A plot of activity
versus nitrogen concentration (Figure 36) showed the lower
level of sensitivity to be on the order of 1 x 10'~ gms . c. Oxygen. An (n,2n) reaction on oxygen-16 produces
1.7 Mev positron-emitting oxygen-15 with a 2.1 minute half - life. For this investigation, analytical hydrogen peroxide
(35s aq. solution) was irradiated for two minutes at 1
Megawatt. A one-minute delay was allowed for sample prepara-
tion, before proportional counting and gamma spectral
determinations were made. According to the plot of activity
,versus oxygen concentration (~igure 3 6 ) , the lower level
of sensitivity is 1 x 10-1 gms.
CALIBRATION CURVE ' (n, 2n)
II NITROGEN =OXYGEN -
4 W a 4
0 -
I J I I
0.01 0 . I 1.0 WEIGHT OF CARBW (GMS x 0.810)
I I
1 J I0 100
WEIGHT OF NITROGEN (MG) I
loL 10' WEIGHT OF OXYGEN (MG)
Figure 36. 'Calibration curve for carbon, nitrogen and oxygen.
4. Discussion
The above procedures for carbon, nitrogen, and oxygen did
not require any chemical separation, however, in the case of
oxygen, a question arises concerning contamination. The
quantitative values obtained would be a composite of the oxygen
in hydrogen peroxide as' well as the water diluent. Attempting
to determine carbon, nltrcrgerl, or oxygen by the 0.511 Mev
annihilation peak in a gamma spectrum is'not too promising.
Carbon determinations in samples' containing only carbon and
hydrogen are feasible but when nitrogen or oxygen are present,
careful extrapolation is required for resolution of the decay
curves. This was evident in the nitrogen analysis of ammonium
thiocyanate. The background and carbori..component 'could be
extrapolated safely only if the decay'was followed for several
hours. If a sample contained carbon, nitrogen, and oxygen, the
0.511.Mev annihilation peak would be a composite of all three
isotopes (i .e . , carbon-11, nitrogen-13, and oxygen-15). They
could still be separated by decay curve resolution but the value
of gamma scintillation spectrometry, namely qualitative and
quantitative results, would be reduced considerably.
(D. Kaiser)
Preliminary Experiments for ' hbtivation Analysis of Thallium
Procedures are being developed for the activation analysis of
thallium in botanical samples and meteorite samples using the short-
lived isotope ~1~~~ (4.2-minute half -life) . A rapid radiochemical procedure has been developed utilizing an
ether extraction and an iodide precipitation which permits separation
of the thallium in about 9 minutes with a yield of 80-8596. ' This
procedure is described in detail in the.section on separations.
. Since this isotope is a pure beta emitter there are special
problems in connection with its assay. Limits of sensitivity and
interferences from contaminants are being. studied for. this determina,-
tion at the present time. . . (c. K. Kim)
Q. Radiochemical Analysis of Long-Lived Ac t iv i ty i n a High Spec i f i c
A c t i v i t y Gold Sample
" After severa l months s torage a sample, cons i s t ing of gold
I evaporated onto an aluminum backing s t r i p , which had been i r r a d i a t e d
~ - i n t h e high f l u x p o s i t i o n of the MTR f o r many days,was found t o
contain a high l e v e l of r e s idua l a c t i v i t y .
~ To i d e n t i f y t h e rad io iso topes present , t he gold was mechanically.
1 removed from the backing s t r i p and t r e a t e d separa te ly . The .gold was
I .found t o contain an appreciable amount of Ag 65 'lorn and a t r a c e of Zn . I The ~n~~ was i d e n t i f i e d from the gamma s p e c t r a a f t e r chemical removal
of the s i l v e r a c t i v i t y as, t he ch lor ide .
The alumincm s t r i p was dissolved i n conc. H C 1 and the s o l u t i o n
I passed over a Dowex 2 i o n exchange column. The a c t i v i t y remaining on
the colurim was found t o be a mixture of co60 and ~n~~ by washing the
column with 1 N H C 1 t o remove the coba l t . The i n i t i a l e l u a t e was
I found t o contain an a c t i v i t y with chemistry s i m i l a r t o lanthanum
I which was probably' 13-year ~ u ~ ~ ~ , and another a c t i v i t y i d e n t i f i e d
V I APPLICATIONS OF TRACERS TO ANALYSIS . , . . ' . ';, . . i
Much of t h e o v e r a l l program of t h i s p r o j e c t i s involved i n t h e
app l i ca t ion of t r a c e r s t o ana lys i s . Most of the problems can be, . ,
categorized i n t o the previous sec t ions on Radiochemica1.Separations .
o r Act ivat ion Analysis. One problem explpred .during the p a s t year
does not f a l l ' i n e i t h e r category, however, and w i l l be .described here .
A. Use of Radioactive Tracers t o Determine S o l u b i l i t y Products
I n the t r a c e r l i t e r a t u r e one of the most widely quoted examples
of th;! use of t r a c e r s i n ana lys is ' i s i n the determination of s o l u b i l i t y
products . "Yet a perusa l of t h e l i t e r a t u r e i n a i c a t e s t h a t t h i s method
has been r e s t r i c t e d pr imar i ly t o work with ' s i l v e r ch lor ide . ' We f e l t
t h a t i t would be use fu l to' explore and eva lua te the techniques requi red ,
t h e accuracy obta inable , 'and the l i m i t a t i o n s inherent i n applying t h i s
method i n general to' the determination of s o l u b i l i t y products .
To t h i s end CO(IO ) AgC1, and ~ 1 1 were used. ~x-perimental ' 3 2'
methods have been devised 'and s t u d i e s made of t h e l i m i t a t i o n s of the
method. A paper i s being prepared which w i l l r epor t t h e experimental
values obtained and d iscuss the advantages and disadvantages of t h i s
method over o t h e r techniques. ( G . Ter ~ a a r )
V I I SEPARATION PROCEDURES
CHEMICAL SEPARATIONS
Element separated: Vanadium 'Procedure by: J . Brownlee 'Q
Target mater ia l : Cracking c a t a l y s t Time f o r s e p f n : 10 min.
Type of bbdt: Neutron ( i n pneumatic tube) Equipment required: Normal 10 min a t r eac to r power l e v e l of 1000 kw
Yield: Variable (up t o 70%)
Degree of p u r i f i c a t i o n : S u f f i c i e n t f o r gamma spectroscopy
Advantages: Complete removal of aluminum; r ap id separa t ion
Procedure:
(1) Fuse 40-100 mg sample ( f i n e l y ground) and g e l a t i n e container with 3-3.5 gm sodium peroxide f o r two minutes. Cool r a p i d l y (known a c t i v i t y of V-48 present a s t r a c e r ) .
(2) Dissolve melt i n so lu t ion containing 16.7 m l conc. H C 1 , 3 m l aluminum c a r r i e r , 0 .5 m l vanadium (+5) c a r r i e r , and 15 m l 3% hydrogen peroxide .
Caution!! SAFETY WINDOW MUST BE DOWN!!
( 3 ) Add 30-ml of 10% soln of 8-hydroxyqulnoline i n 1:4 a c e t i c ac id , p lus -60 m l conc . NH40H ( p ~ 9-10).
(4 ) F i l t e r aluminum p r e c i p i t a t e through 120 mrn medium g l a s s f i l t e r f r i t .
(5 ) A c i d i f y . f i l t r a t e with H C 1 . Cool i n i c e bath o r by adding chipped i c e d i r e c t l y t o f f l t r a t e .
(6) Transfer f i l t r a t e t o 250 m l separa tory funnel containing 5 m l chloroform previously equ i l ib ra t ed with 1-2 - N HC1 .
(7) ~ d d 6-mi 6 5 aqueous cupferron; e x t r a c t f o r one minute. ~ l l o w l a y e r s t o separa te f o r 30-6- seconds.
(8) Transfer chloroform l a y e r t o counting tube; analyze gamma a c t i v i t y on 100-channel analyzer , s t a r t i n g a t 10.0-minutes a f t e r removal of sample from the r e a c t o r .
Chemical y i e ld : Determine with V-48 t r a c e r
CHEMICAL SEPARATIONS . ' .
Element s epa ra t ed : Vanadium Procedure by: Ka i se r
Targe t m a t e r i a l : B i o l o g i c a l t i s s u e ' Time f o r s ep 'n : -5 min.
Type of bbdt: Neutron ( i n pneumatic t ube ) Equipment r equ i r ed : S tandard 1 0 min. at r e a c t o r power l e v e l of 1 Megawatt
Yie ld : 4 0 4 5 %
Degree of p u r i f i c a t i o n : Enough f o r y-spectroscopy
Advantages: Rapid s e p a r a t i o n
Procedure:
(1) I r r a d i a t e sample 1 0 min. a t 1 Megawatt.
( 2 ) Fuse sample i n 1 0 gms. Na202 con ta in ing vanadium-48 t r a c e r , 1 0 mg. of Vanadium c a r r i e r ; and 1 0 mg. of Copper holdback c a r r i e r .
( 3 ) Dissolve mel t i n 50 m l . water , and add 42 m l . conc. H C 1 .
( 4 ) Add 10 G m s . t a r t a r i c a c i d , bubble i n H2S g a s , and f i l t e r .
(5) .Add 10 .ml . 6% aq. Cupferron s o l u t i o n to 'vanadium f i l t r a t e , and e x t r a c t wi th 1 0 m l ; C H C 1 3 .
( 6 ) C o l l e c t o rgan ic l a y e r , and count w i th 100-channel analyze?-.
Chemical Yield: Vanadium-48 Determinat ion.
105
CHEMICAL SEPARATIONS .
Element separated: Cobalt Procedure bjr: Kaiser ' :
v Target mater ia l : ~ i o l o g i c a l t i s s u e Time f o r sepln: . -15 min. :
~ ~ p e of bbdt: Neutron ( i n pneumatic tube) Equipment-required: Standard 30 mln. a t r e ac to r power l e v e l of 1 megawatt
Yield: -40$
Degree of pu r i f i c a t i on : Enough f o r y-spectroscopy
Advantages: Rapid separat ion
Procedure :
(1 ) Place 10 m g . of Co c a r r i e r and known amount of co60 t r a c e r in) . . nickel c ruc ib le . . .. . . I
( 2 ) Add th ree NaOH p e l l e t s and heat so lu t i on t o almost dryness.: . -
(3 ) Two min. before end of i r r a d i a t i o n , add 1 0 gms. of N a 2 0 ~ t o '
cruc ib le and melt . Fuse sample f o r 1 min. (CAUTION!!)
(4 ) Cool outs ide of c ruc ib le by caut iously dipping i n t o beaker of co ld water .
(5 ) ' Dissolve melt by immersion i n t o 50 m l . water. Add 50-70 ml. of i
l i q u i d ni t rogen.
(6 ) Add 15-20 m l . g l a c i a l a c e t i c ac id and cool with add i t iona l 50-70 ml. . l i q u i d ni t rogen.
, . .
( 7 ) Transfer t o 150 m l . s e a r a to ry funnel containing 25 m l . 8-hydroxy- qulnollne so lu t ion (jJw/v i n C H C l ) and shake f o r 1 mln. I
3 (8 ) Ex t rac t organic l aye r w i t h ' l 0 ' m l . 9 M H C l .
( 9 ) Prec ip i t a t e cobal t from aq. l aye r with Na202 and c o l l e c t with f i l t e r chimney. Wash with water and mount f o r measurement.
Remarks :
(1). I f foaming occurs during co l lec t ion , add 10-15 m l . 0.1 - M K C 1 (Step 9 )
(2) Copper and manganese a r e contaminants. . .
CHEMICAL SEPARATIONS
Element separated: Copper . Procedure by: Kalser . . . :
Target mater ia l : . , Biological t i s s u e Time f o r sep'n: 8 min.
Type of bbdt: Neutron ( i n pneumatic tube) Equipment required: Standard 5 min. a t r e ac to r power l e v e l of 1 Megawatt
Yield: 80s
Degree of pu r i f i c a t i on : ' Enough f o r y-spectroscopy
Advantages: Rapid separat ion
Procedure:
(1) I r r a d i a t e . sample f o r 5 min. a t 1 ~ e ~ a w a t t .
( 2 ) .Fuse i n 10 G m s . Na O9 containing 1 0 mg. Cu c a r r i e r neu t ra l i zed with ) : p e l l e t s ~ a 0 6 .-.
( 3 ) Cool n ickel c ruc ib le i n 600 m l . H20.
( 4 ) Dissolve melt i n 50 m l . w a t e ~ and add 30 m l . conc. H C 1 (CAUTION! !) . .
(5) ' Cool so lu t ion with 50-70 m l . l i q u i d n i t rogen.
(6) Add t o 150..ml; separa tory funnel containing 5 m l . of equ i l ib ra ted cc14 (1.2 N H C ~ ) .
. ( 7 ) . Add 10,.ml. 6% aqueous Cupferron so lu t ion and e x t r a c t , f o r 1 min.
(8) Back e x t r a c t Cupferron l a y e r with 10 m l . conc. NH40H.
( 9 ) Prec ip i t a t e Cu with H2S.
(10) Col lec t p r e c i p i t a t e with f - i l t e r chimney.
( l l ) . : ' ~ e t e m i n e a c t i v i t y with 100-channel analyzer.
Remarks :
.chemical yield: Iodometry.
CHEMICAL SEPARATIONS
Element separa ted\ Niobium Procedure by; J. Brownlee
b, Target ma te r i a l : R u t i l e ( T ~ o ~ , N ~ ~ o ~ , v ~ o ~ ) Time f o r sep tn : 1 0 min.
Type of bbdt : Neutron ( i n pneumatic tube) Equipment requi red: Normal, 1 5 min. a t r e a c t o r power p l u s medium s t a i n l e s s s t e e l l e v e l of 1000 kw f i l t e r
Yield: 30-35%
Degree of p u r i f i c a t i o n : S u f f i c i e n t f o r gamma spectroscopy (vanadium completely removed; t i t an ium contamination)
. .
Advantages: Simple, r a p i d separa t ion
Procedure :'
( 1 ) Fuse 100 mg. i r r a d i a t e d sample, contained i n g e l a t i n e , capsule, i n 3-4 gm. 'sodium peroxide f o r -2 minutes. Cool r a p i d l y wi th cold water . (Known a c t i v i t y Nb-95 evaporated before f u s i o n . )
( 2 ) Dissolve melb i n 25-ml water and 20-ml concentrated n i t r i c ac id , and 3 - m l T i c a r r i e r .
1 cau t ion ! ! SAFETY WINDOW MUST BE DOWN ! !
(3) F i l t e r through 60-mm. ' medium g l a s s f r i t . (4) Add 25-ml. concnetrated n i t r i c ac id and 0.5 gm. commercial s i l i c a
g e l ; b o i l f o r one minute.
(5) F i l t e r through medium s t a i n l e s s s t e e l f i l t e r funnel .
(6) ~ r y ' s i l i c a g e l wi th acetone.
( 7 ) Trans fe r s i l i c a g e l t o counting card and analyze wi th 1.00-channel analyzer , s t a r t i n g a t e x a c t l y t e n minutes a f t e r remova4:of sample from r e a c t o r . . .
Chemical y i e l d : Determine wi th . known amount of Nb-95 a c t i v i t y .
Reference: (34)
. CHEMICAL SEPARATIONS . '
Element ~ e p a r a t ~ d : Technetium Procedure by: 'Fukai (daughter of molybdenum) \ ~
Time f o r sep'n: 3O.min. Target mater ia l : Biological ash ( including wait ing period
of -15 min.) I Type of bbdt: Neutron ( i n ' ~ n e u m a t i c tube) . 8
15 min. a t r e ac to r power Equipment required: Standard l e v e l of 100 kw
Yield: 60% . .
Degree of pu r i f i c a t i on : Good f o r y-spectrometry I
. . Advantages: Simple I
Procedure:
Digest the i r r a d i a t e d ash i n 3 m l of hot 12 - M NaOH and add iO m l of H C ~ . (CAUTION! ! )
Add 5 mg of Re-carr ier and 5 m l of sa tu ra ted Br2-water; Allow t o s tand f o r -15 min. while keeping the so lu t ion warm.
Expel Br2 by bo i l i ng without too much bubbling. . 1
Put a watch g l a s s on the beaker as a cover and add 7 g. of NaHC03 c r y s t a l s nimbly without l o s i n g ' t h e contents of the beaker. (CAUTION ! ! )
Dilute the so lu t i on t o 30 m l . by adding water and adjus t pH -8 with a few drops of 4 - M NaOH so lu t ion .
Transfer t he so lu t i on t o a separatory funnel , add 2 m l of 1% t e t r a - phenyl arsonium chlor ide solution.(^^^^) and a g i t a t e f o r 1 min.
Add 20 m l of CHC13 and shake vigorously f o r 2 min.
Separate organic l aye r and add 20 m l of 1 - M H C 1 . Boil o f f CHC13 on hot p l a t e (-3 mln.).
Add 2 m l of Br2-water t o make sure of t he oxidat ion of Re. Heat and expel Br2.
Add f u r t h e r 2 m l of te t raphenyl arsonium chlor ide so lu t ion while ho t .
Cool the so lu t i on with l iquid-ni t rogen and f i l t e r immediately.
Wash with 3 m l of ice-cold water twice and mount f o r counting.
Chemical y ie ld : Determine i n d i r e c t l y f o r known amount of I r r a d i a t e d molybdenum.
. . . . .
Note: By us ing Br -wa te r - in ac id medium t h e r e i s a p o s s i b i l i t y t d l o s e , some p a r t o? technetium.
CHEMICAL SEPARATIONS
Element separated: Tungsten Procedure by: Fukai
Target mater ia l : Biological ash Time f o r sep ln : 30-40 min.
Type of bbdt: Neutron (pool i r r a d . ) Equipment required: Standard '
-6 h a t r e ac to r power l e v e l of 100 kw
Yield: 30%
Degree of pu r i f i c a t i on : Good f o r y-spectrometry
Advantages: Simple and c lean separat ion
Procedure:
(1) Digest the i r r a d i a t e d ash i n 5 m l of hot 12 M NaOH with 10 mg of W-carrier.
( 2 ) Add 10 m l of conc. H C 1 . (CAUTION! ! ) Dilu te t he so lu t ion t o 30 m l making -2 - M H C 1 so lu t ion .
( 3 ) Add 0.2 gm of s o l i d SnC12*2H20 and 0.5 g of s o l i d NHhSCN and heat f o r -5 min. t o form br igh t green complex.
( 4 ) Transfer the so lu t i on t o a separatory funnel , e x t r a c t twice with 30 m l of e thy l a ce t a t e .
(5) Evaporate the organic l aye r i n a 350,ml beaker t o dryness on a hot p l a t e . . #
(6 ) Take up the res idue with 10 m l of 6 M H C 1 and add 5 drops of 30% H202 and 0.5 m l of con'c. HN03".
(7) - vapora ate down almost t o dryness.
(8) Add 10 m l . of 6 - M H C ~ and s t i r vigorously.
( 9 ) F i l t e r the p r e c i p i t a t e , wash twice with 3 m l . of 6 - M H C 1 and mount f o r counting.
Chemical Yield: Weigh as t ungs t i c oxide, W03.
CHEMICAL SEPARATIONS
Element separa ted: Rhenium ' Procedure by: F'ukai
i' Target ma te r i a l : Biologica l ash Time , o f sep 'n: 30 mln.
Type of bbdt: Neutron (pool i r r a d . . ) . Equipment requi red: -12 h a t r e a c t o r power l e v e l Standard of 1000 kw
Yield: 70%
Degree of p u r i f i c a t i o n : S u f f i c i e n t f o r y-spectrometry
~ d v a n t a ~ e s : Simple
Procedure:
( 1 ) Put t h e i r r a d i a t e d ash i n t o a mixture of 1 0 m l of conc. H C 1 and 5 m l of s a t u r a t e d Br2-water, t o which 5 mg of Re-carr ier has a l r eady been added. Dissolve the ash by hea t ing .
( 2 ) Expel Br2 by b o i l i n g without too much bubbling.
( 3 ) Put a , watch. g1,ass on the .beaker a s . a cover and add 7 g . of . N$-IC03 c r y s t a l nimbly without l o s i n g the contents of, t he beaker. (CAUTION ! ! )
( 4 ) Di lu te t h e s o l u t i o n t o 30 m l . by adding water and a d j u s t pH -8 with a few drops of 4 - M NaOH solut ion. .
(5 ) Transfer t h e s o l u t i o n t o a sepa ra to ry funnel , add 2 m l of 1% t e t r a - phenyl arsonium ch lo r ide s o l u t i o n (TPAC) and a g i t a t e f o r 1 min.
( 6 ) Add 20 m l of C H C 1 3 and shake vigorously f o r 2 min.
(7 ) Separa te organic l a y e r and add 20 m l of 1 - M H C 1 . Boi l o f f CHC13 ; on hot p l a t e (-3 min . ) .
(8) Add 2 m l of Br2-w,ater t o make s u r e the o x i d a t i o n . o f Re. Heat and expel Br2.
( 9 ) Add f u r t h e r 2 m l of t e t r apheny l arsonium ch lo r ide s o l u t i o n while h o t .
(10) Cool the s o l u t i o n with l i q u i d n i t rogen and allow. t o s tand f o r 1 5 min.
(11) F i l t e r the p r e c i p i t a t e and wash wi th 3 m l of ice-cold water twice and mount f o r counting.
Chemical y ie ld : Weigh a s te t raphenyl arsonium perrhenate, (C H ) AsRe04. 6 5 4
Note: By us ing Br2-water i n ac id medium t h e r e i s a p o s s i b i l i t y of l o s i n g some of the rhenium.
CHEMICAL SEPARATIONS ' .
Element separated: Gold Procedure by: . F'ukai
Target mater ia l : Biological ash . , Time of sepln: 30 min.
Type of bbdt: Neutron (pool i r r a d . ) Equipment required: . Standard -15 h a t r e ac to r power l e v e l of 1000 kw
Yield: 80s
Degree of pu r i f i c a t i on : F a i r l y good
Advantages: Simple and clean separa t ion
Procedure:
(1 ) Dissolve the i r r a d i a t e d ash i n 15 m l . of aqua r e g i a by heat ing. Add 10 mg.-of Au-carrier . Di lute t o 30 m l . with water .
( 2 ) Transfer the so lu t i on t o a separatory funnel and shake f o r 2 min. w i t h 30 m l . of e thy1 ace t ' a te .
(3)'. Wash organic l a y e r with 15 m l . of 6 - M H C l (1 min. shaking) .
( 4 ) S t r i gold from organic l a y e r by shaking with 25 m l of NH4OH ( l :47 f o r 2 min.
(5) Take aqueous l aye r and add 10 m l of conc. H C 1 t o a c id i fy the so lu t i on .
( 6 ) Heat and bubble SOg i n the so lu t i on f o r 1 5 min. (3-5 bubbles/sec . ) . ( 7 ) F i l t e r the deposited Au, ' wash the p r e c i p i t a t e twice .with cold '
1 - M HC1, and mount f o r counting.
Chemical y ie ld: Weigh as Au metal .
CHEMICAL SEPARATIONS . .
Element s epa ra t ed : Thal l ium Procedure. by: Chong Kuk K i m , .
. . . ,
Targe t m a t e r i a l : P l a n t m a t e r i a l ( l e a f ) Time f o r s e p t n : , 9 min. . , , . . , . . . , . . .
Type of bbdt: Neutron, 1 0 min., 1 MW. Equipment r e q u i r e d : S tandard
Yield: 83% . .
Degree of p u r i f i c a t i o n : Good
Advantages: Rapid s e p a r a t i o n and easy t o run
Procedure:
(1) Dry sample i n oven a t 120'6 and powder i t . '
( 2 ) is solve t h e i r r a d i a t e d sample i n 2 m l of conc. HN03 by h e a t i n g on a h o t p l a t e . When n e a r l y evapora ted t o dryness add ano the r 1 m l . conc. HN03, 1 m l of 75% HClO4 and h e a t t o d ryness . (CAUTION-- Use HC104 on ly a f t e r HN03 t rea tment ! ! )
(3) Add 1 0 m l of 1 N Tf, 1 m l 1 - c a r r i e r (10 mg/ml) and Br water drop- wise t o o x i d i z e T1 t o TI+?. Be s u r e any TlBr p r e c i p i e a t e *resent i s d i s s o l v e d by t h e Br2-water. Keep s o l u t i o n coo l , below 32 C .
( 4 ) T r a n s f e r t h e s o l u t i o n t o a s e p a r a t o r y funne l cont 'a ining 15 m l of i sop ropy l e t h e r , shake v igo rous ly and draw o f f o rgan ic phase . Repeat once more w i t h 15 m l more of i sop ropy l e t h e r .
( 5 ) Combine o rgan ic f r a c t i o n s and h e a t on a h o t p l a t e u n t i l a l l e t h e r i s evapora ted .
. ( 6 ) Add 1 0 m l of 0 .8 N H SO&. Reduce wi th SO2 gas i n - a beaker surilounded wi th c ~ s z e d i c e .
( 7 ) Add 1 N K I i n s l i g h t excess t o p r e c i p i t a t e T l I . Diges t and f i l t e r on to lT f i l t e r pape r d i s c .
( 8 ) Mount f o r count ing .
Note: L,ong-'lived ~1~~~ can be used t o determine chemical y i e l d . - , ' .
VIII PER'SONNEL,' PUBLICATIONS, TALKS, MEETINGS
personnel Li.st ing , .
Pro jec t D i rec to r Meinke, W . W .
P o s t Doctoral ~ u k a i , R. ( ) (~xchange s tudent from Tokyo, japan)
Kaiser , D. ( ) (Michigan Memorial Phoenix P ro jec t No. 151)
~ x c h a n ~ e Students K i m , C. ( ~ o r e a ) 1 .
D a s , S. (1ndia) *
Graduate Students Brownlee, J. *
DeVoe, J. *** ( I )
Ter Ham, C. *
Wahlgren, M. *
Weiss, G .
Undergraduate Students Sargent, M. * * ( I )
***( 1) Sheperd, E.
+**(I) Carlson, J.
** Fry, E.
S t a f f ~ s s i s t h t Maddock, R.. S.
Typing . Blackburn, J . **( ' I
* Y Schwing, J.
* Coleman, F.
* * Elec t ron ics Shide ler , R . 'W. (Fu l l time beginning August 1, 1959)
Nass,
* Half time
* * Hourly ..
*** Hour1.y summer only
( ' ) Terminated
B. Papers and Reports Published
1. Beta-Ray Spectroscopy Using a Hollow P l a s t i c S c i n t i l l a t o r . '
D. G . Gardner and W . W . Meinke. I n t e r n . J: of Appl.
. . Radi.ation and ' I so topes - 3, 232 (1958). 8 pages, 12 f i g s .
2. Act ivat ion Analysis; Radiometric Analysis; Assay of
~ a d i o i s o t o i e s . W . Wayne Meinke . Encyclopedia of Science
and Technology. McGraw-Hill . ( f n p res s , ) .
3 . TTA Extrac t ion Curves. . E. Sheperd and W . W . Meinke. U . S.
Atomic Energy Commission Report AECU-3879 ( ~ c t o b e r 1958).
3 pages, 1 f i g .
4. Radiochemical Separat ions of Indium. W . W . Meinke, I . B.
Ackermann and D. N . Sunderman. .Anal. 'Chem. - 31, 40 (1959) . 4 pages, 2 f i g s .
5. Determination of ( d , a ) Reaction Cross Sec t ions . K . Lynn Hal l
and W . Wayne Meinke . J. Inorg. Nucl . Chem. - 9; 193 (1959).
7 pages.
6. S e n s i t i v i t y Charts f o r Neutron Activat ion ~ n a l ~ s i s . W . Wayne
Meinke. Anal. Chem. - 31, 792 (1959). 4 pages, 3 f i g s .
7. Trace Analysis of Marine Organisms: A Comparison of
Act ivat ion Analysis and conventional Methods. Rinnosuke
Fukai and W . Wayne Meinke . Limnology and Oceanography.
(1n p res s , October 1959).
8. LIAnalyse Chimique Par Act ivat ion Aux Neutrons. Jacques
Fouarge. l l I n d u s t . r i e Chimique Belge - 24, No. 2, 143 (1959).
12 pages.
9. Method f o r the Analysis of Multicomponent Exponential~Dec,ay
Curves. Donald G. Gardner, Jeanne C . Gardner, George Laush
and W . Wayne Meinke. Journal of Chemical Physics. (1n
press , October 1959).
10. search f o r the I so tope Donald G . Gardner and W . Wayne'
Meinke. Phys. Rev. - 114, 822 (1959). 3 pages.
11. Pneumatic Tubes Speed Activat ion Analysis. W . Wayne Meinke.
Nucleonics - 17, No. 9, 86 (1959). 4 pages, 7 f i g s .
12. Isomeric S t a t e of P t lggm. Morris A . Wahlgren and W . Wayne
Meinke. Phys. Rev. 115, 191 (1959) 3 Pages, 3 f i g s * - 1 . Radiochemical Separat ions of Cadmium. James R . DeVoe and
W . Wayne Meinke . Anal. Chem. - 31, 1428 (1959) . 4 pages.
14. Act ivat ion Analysis of Some Trace Elements i n Marine Biological
Ashes. R . Fukai and W . W . Meinke. Nature. (1n p res s ) . . .
15. The Rhodium, S i l v e r , and Indium Content of Some Chondrit ic
~ e t e o r i t e s . U . Schindewolf and M. ~ a h ' l ~ r e n . Geochim. e t
Cosmochim. Acta. (1n p r e s s ) . . .
16. Activat ion Analysis of Trace Cobalt i n Tissue Using 10.5-Minute
cobalt-60m. David G . Kaiser and W . Wayne Meinke. Talanta .
( ~ n p r e s s ) .
17. Source Mater ial f o r Radiochemistry, Nuclear Science S e r i e s
Report No. 27, Subcommittee on Radiochemistry, National
Research Council, WasNngton 25, D. C. 23 pages.
18. Tellurium-Selenium Content i n .Meteorites. U . Schindewolf.
Geochim. e t Cosmochim. Acta. (submit ted) .
19. Nucleonics i n Analysis--ASTM B u l l e t i n . (1n p r e s s ) .
20. Is,omerism of Iig1O8. M. A . Wahlgren and W. W . Meinke. Phys.
Rev. (submitted) .
C. Talks
1. J. L. Brownlee, Jr., "Interaction of Beta-Radiation With
. Matter", U. of M. Chemistry Department Seminar, Ann Arbor,
November 12, 1958.
2. W. W. Meinke, "The Nuclear Reactor: Activation Analysis and
Other Applications", Symposium on the Contribution of
Selected Physical Methods to the Solution of Structural and
Analytical Problems, Indiana Section of American Chemical
Society, Indianapolis, December 6, 1958.
3. W. W. Meinke, "Activation Ana.lysis Using Short-Lived
Activities", Nuclear Chemistry Seminar, University of Chicago,
February 18, 1959.
4. W. W. Meinke, "Nucleonics in Analysistt, The Pittsburgh
Conference on Analytical Chemistry and Applied Spectroscopy,
~ittsburgh, March 2, 1959.
5. W. W. Meinke (with J. L. Brownlee, Jr.), "~etermination of
Vanadium in Petroleum Process Streams by Neutron Activation
and Gamma Scintillation Spectrometry", ~nalytical Division,
American Chemical Society, Boston, April 8, 1959.
6. W. W. Meinke, "Nucleonics in Analytical Chemistry", Analytical
Group, Western New York Section, American Chemical Society, .
Niagara Falls, New York, April 14, 1959.
7. W. W. Meinke, "Trace Element Analysis as Applied to Meteoritesft,
Astronomy Colloquium, University of Michigan, Ann Arbor,
April 24, 1959.
8. J. R. DeVoe, "Radiochemical Separations", U. of M. Chemistry
Department Colloquium, Ann Arbor, May 21, 1959.
\
. . 9 . W . W . Meinke, "Rapid Activat ion Analysis With a Univers i ty
Research ' ~ e a c t o r " , Sympsoium on Radioact ivat ion Analysis
sponsored by t h e I n t e r n a t i o n a l Atomic Energy Agency.Joint
-Commission on Applied Radioac t iv i ty . Vienna, Austria,,
June 1-3, 1959.
10. W . W . Meinke, Eight . l ec tu res on bas i c r a d i o a c t i v i t y and nuclear
physics presented before the AEC-NSF Summer I n s t i t u t e of
Radiobiology,, Ann Arbor, Michigan, June 23-29, 1959.
11. W . W . Meinke, "Nucleonics i n . . Analysis". Also Chairman of \
Ful l Day Symposium on Radioisotopes i n Metals Analysis and
Test ing, American s o c i e t y f o r Test ing Mater ia l s , A t l an t i c City,
New Jersey , June 22, 1959.
12 . W . W . Meinke, "Nucleonics", Five Lectures ' i n National Science
Foundation Summer Conference f o r College Teachers, Recent ' . .
Advances i n Analyt ical Chemistry, Carleton College,
. Northf ie ld , Minnesota, June 30-July 3, 1959,
13. J . R . DeVoe (with W . W . ~ e i n k e ) , "The Application of Vacuum
D i s t i l l a t i o n of Metals t o Radiochemical Separations",
Symposium on Radiochemical Analysis, American Chemical
Society, A t l an t i c Ci ty , New Jersey , September 18, 1959.
14,. W . W . Meinke, " U t i l i z a t i o n of Short-Lived Radioisotopes i n
Act ivat ion Analysis", Third I n d u s t r i a l Nuclear Technology
Conference, .Chicago, ~ l i i n o ~ s , September .22, 1959.
15. W .. W . Meinke,. .!'Activation Analysis f o r Trace Elements",
Midwestern Sect ion, Socie ty of Nuclear Medicine;Ann Arbor,
Michigan, October 11, 1959.
16. W. W. Meinke, "Application of Radioactivity to Analytical
Chemistry", Nuclear Reactor Symposium, Washington State . . ,
University, Pullman, Washington, October 19, 1959:
17. W. W. Meinke, "Activation ~ n a l ~ s i s With 'the Ford Nuclear I
Reactor of the University of Michigan", Seventh Detroit
Anachem Conference, Association of Analytical Chemists,
Detroit, October 26, 1959. I
. . D. , Committee Meetings , .
. . . . . . ' .
1. W. W. Meinke, Committee on Nuclear Science, National Research
Council, National Academy . . of Sciences Building, Washington,
D. C., November'7, . . 1958.
2.. W. W. Meinke, Subcommittee on Radiochemistry, Committee on
Nuclear Science, National ~esearch'council, Ann Arbor, . .
Michigan, December 8, 1959. . .
3. W. W. Meinke, Subcommittee on Radiochemistry, Committee on
Nuclear Science, National Research Council, Washington, D. C.,
May 2, 1959.
4. W. W. Meinke, N2 Sectional Committee on General and
Administrative Standards, American Standards. Association .
(American Chemical Society representative), New York City,
October 6, 1959. \
5. W. W. Meinke, Subcommittee on Radiochemistry, Committee on
Nuclear Science, National Research Council, Berkeley,
California, October 9, 1959.,
I X ACKNOWLEDGEMENTS
1
We g r e a t l y apprec ia te the kind cooperation of Professor A
H . J. Gomberg, A . H . Emmons, C . W . Rlcker and the s t a f f of the
Michigan Memorial Phoenix Pro jec t i n arranging f o r labora tory
space and r e a c t o r i r r a d i a t i o n s f o r t h i s research . Pa r t of t h i s
work was supported by Phoenix P ro jec t s Nos. 95, 121 and 151.
The help of the I so topes DTvision of the Oak Ridge National
Laboratory i n supplying a number of radioisotope.^ f o r t h i s work
i s acknowledged. . .
122
X LIST OF REFERENCES . .
1. Meinke, W . W . , Nucleonics - 17, No. 9, 86 (1959).
2. Meinke, W . W. , "Progress Report No. 6 " , U . S. AEC Pro jec t No. 7,
Contract No. ~ ~ ( 1 1 - 1 ) - 7 0 ; AECU-3641 (~ovember 1, 1957)
3. Meinke, W; W . , "Progress Report No. 7", U . S. AEC Fro j e c t No ; 7,
Contract No. ~ ~ ( 1 1 - 1 ) - 7 0 ; AECU-3887 (~ovember 1, 1958,).
4 . Meinke, W . W . , Anal. Chem. - 28, 686 (1958).
.' 5. Hoogenboon, A. M . , Nuclear I n s t r ~ m e n t s - 3, 57 (1958 ) . 6. Ha l l , K . L., "Determination of ( d , a ) Reaction Cross Sect ions",
Doctoral Thesis , Department of Chemistry, Univers i ty of Michigan.
U . S. Atomic Energy Commission Unclass i f ied Report AECU-3126. . "
(~ep tember 1955).
7. Ha l l , K . L. and Meinke, W . W . , J. Inorg. Nucl. Chem.. 2, 193 (1959).
8.. Gardner, D. G . , Gardner, J . C . , Laush, G . and Meinke, W . W . ,
"Method f o r the Analysis of Multicomponent Exponential Decay
Curves", J . Chem. Phys . ( ~ c t o b e r 1959).
9. Gardner, D. G . and Meinke, W . W . , Phys. Rev. - 114, 822 (1959).
10. Wahlgren, M. A . and Meinke, W . W . , Phys. Rev. 115, 191 (1959).
11. Strominger, D. , Hollander, J. M . and Seaborg, G. T., Revs. Mod.
Phys . 30, 683 ' (1958 ) . - 12. Lazar, N . H. , IRE Trans. Nuclear S c i . NS-5, 138 (1958).
U
13. 'Coryel l , C . D. and Sugarman, N . , "Radiochemical S tudies . F i s s ion
Products", National Nuclear Energy Se r i e s ' IV , Vol. 9, McGraw-
H i l l , New York, 1951, p . 860.
14 . . Schindewolf, U . and Wahlgren, M . , "The Rhodium, S i l v e r , and Indium
Content of Some ~ h o n d r i t i c ~ e t e o r i t e s " , Geochim, e t Cosmochim.
Acts. (1n p r e s s ) .
Source Mater ial f o r Radiochemistry, Nuclear Science Se r i e s Report .
No. 27, National Research Council, Washington, D. C . , March 1959.
DeYoe, J . R . and Meinke, W. W . , Anal.. Chem. 2, 1428 (1959).
Fronaeus, ,S. , Ostma.n, C . 0.;' Acta Chem. Scand. 8, 961 (1954).
Sunderman, D. N . and Meinke, W . W . , Anal. Chem. - 29, 1578 (1957).
Meinke, W . W. , "progress Report No. 4", U . S. AEC Pro jec t No.. 7,
Contract No. ~ ~ ( 1 1 - 1 ) - 7 0 ; AECU-3116 (~ovember 1, 1955).
Randles, J . E. B., Somerton, K . W . , Trims. Faraday Soc. - 48,. 951
(1952). . .
Randles, J. E. B. and Somerton, K . W . , -- Ib id 48, 828 (1952).
Randles, J . E. B., .Trans. Faraday Soc. - 48, 828 (1952).
Fronaeus, S., Acta Chem. Scand. - 7, 764-73 (1953). (English) - 8, '
412 (1954).
E r sh le r , B. V., J . Phys. Chem. U.S.S.R. - 22, 683 (1948).
Booth, J., Andrieth, A. , Boi le r , J . C . , " ~ n o r g a n i c Synthesis" ,
McGraw-Hill Co., New York (1939).
Meinke, W . W . , Ackermann, I . B. and Sunderman, D. N . , Anal. Chem.
31, 40 (1959). - Rodden, C . J . , "Analytical Chemistry .of t h e Manhat t a n P ro jec t I' ,
National Nuclear Energy Se r i e s , Vol. I . McGraw-Hill Co. (1950)
P * 396.
DeVoe , J . R . , "~adiochemica l Separat ions of Cadmium and Application
of Vacuum D i s t i l l a t i o n of Metals t o Radiochemical SeparatLonsM,
Doctoral Thesis , Department of Chemistry, Univers i ty of Michigan,
November 1959.
Meinke, W . W . , Anal. Chem. - 31,' 792 (1959).
30. Fouarge, J., 1 ' I n d u s t r i e Chlmlque Eclge - 24, N o . 2 , 143 (1959).
31. Fukai, R., and Meinke, W. W., "Analysis of Trace ~lements i r i "
Marine Organisms. A Comparison of Activation Analysis a d
Conventional Methods" , Limnology and Oceanography. (1n press) . 32. Schindewolf, U., "Tellurium-Selenium Content in Met'eoritestt,
(submitted to Geochim. et. ~osmochim. ~c'ta) . 33'. Anders, 0. U., U. S. Atomic Energy ~omnhssion, Rept. AECU-3513,
1 . . April 1957.
34. Roake, W. E., U. S. Atomic Energy Commission, Rept . AECD-3201 (~eclassified, January 1951).
35. Rothstein, A., U. S. Atomic Energy Commission, Rept. UR-262 (,June 5,
