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Linear accelerator radiography
Domanus, J.; Hansen, J.
Publication date:1973
Document VersionPublisher's PDF, also known as Version of record
Link back to DTU Orbit
Citation (APA):Domanus, J., & Hansen, J. (1973). Linear accelerator radiography. Risø National Laboratory. Risø-M, No. 1599
A. E. K. Risø Risø-M-Li^ Title and author(s)
LINEAR ACCELERATOR RADIOGRAPHY
by
J. Domanus
and
Johnny Hansen
3o pages - f 12 tables + 68 illustrations
D a "
Dep?'tmcnt oi !ro p
Metallurgy f-p
Group's own registration .>jrrber(s)
A-173
Abstract
A description is given of the Risø lo MeV linear
accelerator, which was used for radiography of steel
(5o to 25o mm thick). Different X-ray film and inten
sifying screen combinations were tested and charac
teristic curves and exposure charts were computed.
X-ray film speed and contrast were calculated.
Radiographic image contrast and quality were investi
gated and the best combination of X-ray film and screen
was chosen.
Conclusions were drawn about the possibility of
using the Risø accelerator for industrial radiography.
Copies to
Prof . A.R. Mac\ir.;.osh
Dr. F . J u u l
Dr. C F . .Jacobsen
M. Møller-Mads*..-;
Me ta l l u rgy Dept . (^o)
A c c e l e r a t o r Bep<-. (5)
Abstract to
Available on request from the Library of the Danish Atomic Energy Commission (Atomenergikommissionens Bibliotek), Risø, Roskilde, Denmark. Telephone: (03) 35 51 01, ext. 334, telex: 1*3116
I6BM 87 55o ©197 1
LTNBU ACCELERATOR
RADIOGRMBY
ty
J . Donanus
Elsinore Shipbuilding and Engineering Co., Ltd., Helsingør
and
Metallurgy Department. Banish Atonic Energy Commission,
Research Establishment Risø
and
Johnny Hansen
Accelerator Department, Danish Atonic Energy Commission,
Research Establishment Bise
March 1975
Work performed under contract between the Elsinore Shipbuilding
and Engineering Co., Ltd. and the Metallurgy Department of the
Danish Atomic Energy Commission, Research Establishment Rise.
- 2 -
CONTENTS
Page Introduction ............ 7
Description of the accelerator 7
2.1. The accelerator 7
2.2. Beam parameters 8
2.3« Description of the Bremsstrahlung converter ....... 9
X-ray film and intensifying screens 9
Exposure technique 11
Exposure conditions 11
Slotted steel wedge 12
Characteristic curves of X-ray films 13
7.1. Direct exposure 13
7.2. Exposure through steel 13
Intensification factors 1*+
Film speed and contrast 15
9.1. Film speed 15
9.2. Film contrast 18
Attenuation in steel 2o
Radiographic image contrast • 2o
Radiographic image quality 23
Film unsharpness • 26
Exposure charts 28
Summary of conclusions 29
References J>o
Figures 31
- 3 -
FIGURES Page
Fig. 1. Calculated lo MeV Bremsstrahlung spectrum for the
converter 31
Fig. 2. Intensity distribution in the X-ray beam 32
Fig. 3. Elements of the steel block 33
Fig. 4. Steel block after assembly 33
Fig. 5« Construction of the slotted steel wedge J>k
Fig. 6. Steel wedge in its full length 33
Fig. 7* Four slotted steel wedges 33
Fig. 8. Positioning of the slotted steel wedge between
the masking steel plates 36
Fig. 9. Do 37
Fig. lo. Characteristic curves (no filtration) for Kodak Microtex films 3d
Fig. 11. Characteristic curves (no filtration) for Structurix D2 films 39
Fig« 12. Characteristic curves (no filtration) for Structurix Dk films *K>
Fig. 13* Characteristic curves (no filtration) for GAF loo films *H
Fig. Ik, Characteristic curves (no filtration) for GAF 2co films ^2
Fig. 15. Characteristic curves (no filtration) for GAF ^00 films ^3
Fig. l6. Characteristic curves (no filtration) without intensifying screens *"
Fig. 17. Characteristic curves (no filtration) with 1 + 1 mm Pb screens • ^5
Fig. l8. Characteristic curves (no filtration) with 1.3 + 1.3 mm Pb screens ™
Fig. 19. Characteristic curves (no filtration) with 1.3 + 1.3 mm Cu screens ^7
Fig. 2o. Characteristic curves (through 5o-15o mm Fe) for Kodak Microtex films with 0.I5 + o,25 mm Pb screens ... ™
Fig. 21. Characteristic curves (through 5o-25o mm Fe) for Kodak Microtex films with 1 + 1 mm Pb screens ^9
Fig. 22. Characteristic curves (through 5o-15o mm Fe) for Kodak Microtex films with 1 + 1 mo Cu screens... 5°
Fig. 23. Characteristic curves (through 5°-25o ™" Fe) for Kodak Microtex films with SMP lol screens 51
- k -
Page
Fig. cik. Characteristic curves (through 5o-25o mm Fe) for Kodak Microtex films with SMP ?ol screens ^
Fig. 25. Characteristic curves (through 5o-15o mm Fe) for Structurix D2 films with 0.I5 + o.25 mm Pb ocrc-cr;.- ',-;
Fig. 26. Characteristic curves (through 5°-15o mm Fe) for Structurix D2 films with 1 + 1 mm Cu screens r-~l,
Fig. 27. Characteristic curves (through 5°-15° mm Fe) for Structurix Bk films with 0.I5 + o.25 mm Pb screens ..... ;..
Fig. 28. Characteristic curves (through 5o-15o mm Fe) for
Structurix D*f films with 1 + 1mm Cu screens %
Fig. 29. Attenuation curve in steel 57
Fig. 3°. Visibility of slotted wedge on Kodak M films with 1 + 1 mm Pb screens 58
Fig. 31. Visibility of slotted wedge on Kodak M films with SMP lol screens 59
Fig. 32. Visibility of slotted wedge on Kodak M films with SMP 3ol screens 60
Fig. 33« Visibility of slotted wedge on Kodak M films with 0.I5 + 0.23 mm Pb screens 61
Fig. 3 » Visibility of slotted wedge on Kodak M films with 1 + 1 mm Cu screens 62
Fig. 35« Visibility of slotted wedge on Structurix D2 films with 0.I5 + 0.25 mm Pb screens 63
Fig. 36. Visibility of slotted wedge on Structurix D2 films with 1 + 1 mm Cu screens 64
Fig. 37. Visibility of slotted wedge on Structurix D^ films with 0.I5 + o«25 mm Pb screens 65
Fig. 38. Visibility of slotted wedge on Structurix Dh films
with 1 + 1 mm Cu screens 66
Fig. 39» Scanning densitometer 67
Fig. ho. Per cent IQI sensitivity 68
Fig. kl. IQI sensitivities for 1 + 1 mm Pb screens • 69
Fig. kZ. Do 7o
Fig. V3. IQI sensitivities for 1.5 + 1.5 w® P° screens 71
Fig. kk. Do 72
Fig. k$. Do. 73
Fig. h6. Do 7^
Fig . hj. IQI s e n s i t i v i t i e s for 1.5 + 1.5 mm Cu screens 75 F ig . kS, IQI s e n s i t i v i t i e s for d i f fe ren t f i lm-screen-
combinations 76
F i g . '+9. Geometric unsharpness of the radiographic image 77
: :ife
i'i£;. ljo. Exposure charts for Kodak M and o. 15 + o..''5 •:;?:< Pb
screer.s 75
Fir. ;>L. Exposure charts for Structurix D2 and Lk with
0.I5 + 0.25 mm Pb screens 7 )
Kir. '-.'. Comparison of exposure charts from figs. 5o and 51 80
Vir.. '• '•. Exposure charts for Kodak M and 1 + 1 mm Pb screens .... Si
Fif;. lA. Exposure charts for Structurix D2 and Dk with 1 + 1 mm Pb screens 3c
Fig. 55. Exposure charts for GAF films with 1 + 1 mm Pb screens 83
Fig. 56. Comparison of exposure charts from figs. 53-55 Sh
Fig. 57. Exposure charts for Kodak M with 1.5 + 1.5 mm Pb screens 85
Fig. 58« Exposure charts for Structurix D2 and D^ with 1.5 + 1.5 mm Pb screens 36
Fig. 59« Exposure charts for GAF films with 1.5 + 1»5 mm Pb screens 8?
Fig. 60. Comparison of exposure charts from figs. 57-59 ••••••••• 88
Fig. 61. Exposure charts for Kodak M witn 1 + 1 mm Cu screens 39
Fig. 62. Exposure charts for Structurix D2 and Dk with
1 + 1 mm Cu screens 9°
Fig. 63. Comparison of exposure charts from figs. 61-62 91
Fig. 6k. Exposure charts for Kodak M with 1.5 + 1.5 mm Cu screens 92
Fig. 65. Exposure charts for Structurix D2 and D*+ with 1.5 + 1.5 mm Cu screens 95
Fig. 66. Exposure charts for GAF films with 1.5 + 1.5 mm Cu
screens 9^
Fig. 67. Comparison of exposure charts from figs. 64-66 95
Fig. 68. Exposure charts for Kodak M with 1 + 1 mm Pb, SMP lol, and SMP 3ol screens 96
- 6 -
TABLES
Page
Table 1, X-ray films and intensifying screens lo
Table 2. Thicknesses of the slotted steel wedge 12
Table 3* Intensification factors Ik
Table k. Relative film speeds (exposed without steel
filtration) 16
Table 5» Relative film speeds (exposed through steel) ........ 17
Table 6. Relative intensification factors 18
Table 7. Average gradients of X- ray films 19
Table 8. Thickness regions in mm of Fe of slot
visibility on radiographs 21 Table 9. Maximum density differences for different
per cent slot depths 22
Table lo. Wire diameters of the ISO IQI's 23
Table 11. Film densities during radiographic image
quality investigations , 2k Table 12. Film unsharpness 26
- 7 -
1. INTRODUCTION
Since i960 a lo MeV Varian Model V-77oo linear accelerator has been
used at Bisø for radiation chemistry, dosimetry and sterilization purposes.
It was decided to test the possibility of using this accelerator to per
form radiography of thick steel castings.
The purpose of this investigation was to establish a correct exposure
technique and to test the influence of different exposure factors on radio
graphic image quality.
In the first instance different X-ray film bands and intensifying
screens were tested to determine characteristic curves and exposure charts
for steel from 5o to 25o mm. From these curves, intensification factors
for different film-screen-combinations were calculated.
Next, for different film-screen-combinations optimum radiographic
image contrast and image quality were investigated. For that purpose a
special slotted wedge penetrometer was used as well as ISO wire image
quality indicators.
In the future other exposure factors (e.g. focus size, and focus film
distance, and scattered radiation) will be investigated as well.
2. DESCRIPTION OF THE ACCELERATOR
2.1. The accelerator
The Risø accelerator is a two-section S-band electron linear accele
rator with a maximum average output power of approx. 4.5 kW at lo MeV.
The linear accelerator is essentially a pulsed source of high energy elec
trons, with pulse lengths adjustable from o.2f> to 7 lis at peak pulse cur
rents up to max. 32o mA. At a pulse lenjtl* of 7 p.s the maximum pulse cur
rent is 21o mA. The pulse repetition rate is stepwise variable from a
single pulse to 3°° pulses per second. The pulse shape is fairly rectan
gular with a rise time of the order of o.l (J.s.
The two accelerator guides, each 1 ra long, are horizontally placed,
and the electron beam can be directed through A straight-ahead window or
down through a 9o bending magnet and a scanning system for irradiation of
products carried on a conveyor. For the conversion of the electron beam
into X-rays, a Bremsstrahlung converter is placed in front of the straight-
ahead window in the beam centre line.
- 8 -
The electron beaa inside the accelerator has a diaæter of about k mm
and a divergence of a few milliradians before it leaTes the vacuum system.
Scattering occurs at the 0.I5 an aluminium foil exit window, and the emerg
ing beaa is auch aore divergent. Within a distance of 50 ca froa the exit
window the electron beaa in air has an alaost linear divergence. At 50 ca
its intensity decreases 5o)f froa the centre to the edge of a 32 aa diaaeter
field.
2.2. Beaa paraaeters
To keep the radiation conditions as stable as possible beaa paraaeters
such as bear energy and average beaa current aust be controlled. In the
straight-ahead aode of the accelerator there are no possibilities of con
tinuous control of electron energy during irradiation. This aeans that
after the initial warm-up period, the aachine has to be checked a few tines
during the day because of further, gradual stabilisation or fading of vari
ous circuits«
The energy and current paraaeters deteraine the dose distribution
throughout the saaple as well as the average dose rate. To obtain repro
ducible radiation conditions froa one irradiation period to another, the
dose rate at a given position is seasured by aeans of a dosiaeter.
A relative aeasure of the electron energy is readily available as the
accelerator is fitted with a bending aagnet, and the aagnet current needed
to bend the beaa through the 9o angle is proportional to the electron
energy. Initial calibration of the bending aagnet has shown that it is
possible to reproduce the aain energy coaponent with an accuracy of about
l£. Measurement« of the current versus energy have shown that at lo MeV
6oj£ of the peak bean current is contained within an energy band of lojf.
An absolute Beasureaent of the beaa current can be aade by having the
electrons absorbed in a aluainiua or graphite plate thick enough to absorb
all the electrons entering it and by aeasuring the resulting current flow*
ing to ground-potential. (The backscatter correction is less than 2% for
aluminium at lo MeV). A continuous aeasure of the peak pulse current can
be made by means of a non-intercept monitor consisting of a toroidal pick
up coil, which is mounted around the beaa centre line. The average cur
rent, determined froa the peak pulse current, the pulse length and the
pulr;e repetition rate, nay change up to 15&S in the course of one day if no
r '>-.'],ju:;i,mentc are made. For the measurements described in this report
!:''iU'.M. -Urt.;: nnd stops of the accelerator have been required, which may
- 9 -
implicate dose variations of no more than lo%«
2*3* Description of the Breasstrahlung converter
The converter consists of three sections: a tungsten plate, a
cooling water slab, and a stainless steel backing plate. The X-ray pho
tons are produced in the tungsten target by the stopping of the high
energy electrons, while the water slab and the backing plate, which are
located downstream froa the tungsten disc, act as an electron filter as
well as a hardener of the X-ray spectrin. Fig. 1 shows a calculated
Breasstrahlung spectrum for the converter«
As most of the bean power is stopped in the tungsten target, this
causes a heavy thermal load, i.e. the permissible •jp*w"i beam diaaeter
on the target is deterained by the bean power and the mechanical proper
ties of the material. From calculations on the converter target a minimum
beam diaaeter of 2o mm was found necessary, lest the tungsten disc should
not be damaged when the accelerator is operated at full output power«
From measurements on the electron beaa, showing the beaa divergence in air,
a distance of 2o ca from the accelerator exit window to the converter was
chosen. At this distance the beam diameter containing 8ojt of the total
electron current has increased to approximately 25 aa.
At a distance of 5o ca froa the converter the forward angular inten
sity of the X-ray beam has been measured as absorbed dose rate by means of
"Super-Fricke" dosimeters « The results are shown in fig. 2 as the
polar coordinates of the rate of the relative absorbed dose in water as a
function of the angle. In the practical application, the dose rate in any
given geometry has to be measured. The saaple was positioned at a dis
tance of 2 a from the converter in the beaa centre line and the dose rate
in water has been measured to o*2 Krad/h.
3- X-RAY FX1K3 AND InTENSIFnNS SCBEEHS
Kodak Microtex, Agfa-Gevaert Structurix D2 and D4, and GAF loo, 2oo
and 4oo X-ray films were used.
Metal intensifying screens: lead Co, 15 + o.25; 1 + 1 and 1.5 + 1.5
am) i copper ( 1 + 1 and 1.5 + 1*5 am) as well as fluorometalic Kyokko SMP
lol and SMP 3ol screens were used*
Table 1 shows what combinations of films and screens were used in
the various stages of the investigation.
- 11 -
*. EXPOSURE TECHNIQUE
The tunesten target was placed at a distance of 2o n fro« the elec
tron exit window of the accelerator, and X-ray films (in cassettes) were
positioned at 2 m distance froa the target. The distance between the filn
and a concrete wall of the accelerator cell was about 1 ••
In front of the film, steel plates (or eteel penetraæters of differ
ent thicknesses froa 5° to £5<> ••) were placed«
The accelerator was run at lo MeV with an electron current of loo or
2oo sA. The pulse length was 7 *LS. The pulse repetition rate was either
57 or Joo pulses per second«
For short exposures (no steel filtration) 2oo aA and 3oo pps were
used whereas for longer exposures loo aft and 37 PP» have to be applied to
prevent overheating of the accelerator exit window. The end results ere
all relative to a loo aA electron current.
Changes in exposure tiae were aade by changing the nuaber of pulses,
keeping all other paraaeters constant.
5. EXPQSUHE CONDITIONS
X-ray films in plastic cassettes, froa which air was evacuated to en
sure better contact between fila and screens, were exposed either directly
to X-radiation cr through adequate filtration of steel«
For filtration purposes steel plates were used, ranging froa 5© aa
( one plate) up to 25o aa (five plates). Each plate (2oo x 3oo an) was
surrounded by additional Masking steel plates: froa the bottoa and top by
loo x 5oo on plates, from the sides by 15o x >x> •• plates« Thus a steel
block was formed having the surface of 5oo x 5oo aa and the thicknesses
from 5o to 25o as. A U the eleaents used for the construction of such a
block are seen on fig. 3* To keep the whole construction together a steel
frame was used (at left of fig. 3)* Fig. h shows the whole assembly.
In front of the steel block wire type iaage quality indicators (IQI)
were placed during the investigation of the radiographic image quality.
- 12 -
6. SLOTTED STEEL WEDGE
For the investigation of radiographic contrast sensitivity a slotted
steel wedge was used. The wedge was fabricated from a 25o mm thick steel
plate, 12oo mm long. In this plate rectangular grooves were machined,
having the following per cent depths: 0,25; 0.5; l.o; 2.o and 5.o. The
grooves were lo mm wide and spaced 2o mm from each other with a distance
of 35 mm from the wedge edges (see fig. 5)» At the top the wedge was 5o
mm thick and at the bottom 25o mm thick* At a distance of 17.5 mm from
the edge 11 holes (5 mm in diameter and loo mm deep) were drilled at both
sides of the wedge at intervals of 5o mm. These holes served as distance
calibration points for the radiographs. Through the black spots, which
these holes produced on the radiographs, parallel lines were drawn corre
sponding to the thickness of the step wedge (see table 2).
After machining the grooves in the steel wedge, the wedge was cut
into four pieces each of a length of 3oo mm (figs. 6 and 7). The thick
nesses of the four steel wedges are: 5o-loo; loo-l^o; 15o-2oo and 2oo-
25o mm.
Table 2. Thicknesses of the slotted steel wedge (mm)
Thickness range-mm
Calibration hole
Distance from
wedge edge-cm
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0
27.5
No.
1
2
3
it
5
6
7
8
9
10
11
50-100
54.2
58.3
62.5
66.6
70.8
75.0
79.1
83.3
87-5
91.6
95-8
100-150
104.2
108.3
112.5
116.6
170.8
125.0
129.1
133-3
137-5
141.6
145.8
150-200
154.2
158.3
162.5
166.6
170.8
175-0
179-1
183.3
187.5
191-6
195-8
200-250
204.2
208.3
212.5
216.6
220.8
225.0
229.1
233.3
237-5
241.6
245.8
- 1 3 -
Each slotted steel wedge was positioned between the masking steel
plates as shown on figs. 8 and 9. The bottom and side masking plates had
a thickness corresponding to the bottom thickness of the wedge, whereas
the top masking plate had a thickness equal to the top thickness of the
wedge.
The slotted steel wedge was used as a defectometer for the determina
tion of the radiographic image contrast* The use of such a defectometer
was previously described for X-rays and for gammarays . It was also
used for a similar investigation in Co ° radiography with satisfactory
results.
7. CHARACTERISTIC CURVES OF X-RAT FIIMS
Characteristic curves were computed for different X-ray film and in
tensifying screen combinations (as shown in table 1) and for exposures
with and without different steel filtration.
7.1. Direct exposure
Kodak Microtex, Agfa-Gevaert Structurix 02 and D4, GAF loo, 2oo and
4oo X-ray films with and without l.o + l.o and 1.5 + 1.5 mm lead and 1.5 +
1.5 mm copper screens were directly exposed to the accelerator X-rays
(without steel filtration) (table 1-marked o).
Film densities up to 5.0 were read on a "Quanta log" Macbeth trans
mission densitometer* The characteristic curves were drawn for different
exposures, given as number of pulses* They are presented on figs, lo to
15* On those curves thicknesses of the intensifying screens are given
("o" means "no screens").
Figures 16 to 19 give a comparison of characteristic curves of various
films for the same intensifying screens.
7.2. Exposure through steel
Kodak Microtex films with 0.15 + o.25 and 1 + l m m P b , 1 + l m m C u
metal intensifying screens and SMP lol and SMP 3ol fluorometalic screens
as well as Agfa-Gevaert Structurix D2 and D4 films with 0.15 + o.25 mm Fb
and 1 + 1 mm Cu-screens were exposed through steel wedges of various thick
nesses (see table 1). From the radiographs of steel wedges density read
ings were made at different wedge thicknesses (as shown in table 2), and
- 1 4 -
from these readings characteristic curves were computed as shown on figs.
2o to 28. On these figures wedge thickness ranges are marked, and for
each range 11 curves are given. Each curve corresponds to the thickness
specified in table 2 (first curve to the left corresponds to line No. 1,
last curve to the right corresponds to line No. 11). Because of overlap
ping less than 11 curves are reproduced for a given thickness range. On
some curves there is a lack of continuity and some curves are displaced in
different pulse number regions. This was due to the fact that during a
series of exposures of the wedge the required density range could not be
reached and the exposures were repeated later. This was connected with
another setting of the accelerator parameters and it was difficult to ob
tain exactly the same dose per pulse in the X-ray beam. Therefore, for
the same number of pulses different doses of radiation were absorbed by
the film (for explanation see section 2).
8. INTENSIFICATION FACTORS
From the characteristic curves shown on figs, lo to 15 intensification
factors for lead and copper screens were calculated (as the relation be
tween number of pulses necessary to give the same film density for the
film exposed with and without intensifying screens).
Table 3. gives the results of these calculations.
Table 3- Intensification factors
Film
Kodak Microtex
S t n W i x D2
GAF 100
200
'too
Intensifying screens
1 + 1 mm Pb
5.10
5.*0
5.01
5.97
5.13
k.29
1.5 + 1.5 mm Pb
hA9
4.71
3 . «
5.89
3.92
3.56
1.5 + 1.5 ™ Cu
1.6*
1.69
1.83
2.11
3-39
2.00
- 15 -
In computing table 3 intensification factors were first calculated
for the following densities: o.5; l.o; 1*5; 2.o; 2*5; 3.0; 3-5 and *f.o.
Next, for each film-screen-combination, mean values of intensification
factors for all those densities were calculated; these valves are given
in table 3»
As can be seen, the best intensification is obtained with 1 + 1 mm
lead screens. Copper screens give much poorer intensification than lead
of the same thickness.
9. FIW SPEED AND CONTRAST
Speed and contrast of different X-ray film-and-screen combinations
were determined using the American Standard Method for the Sensitometry of
Industrial X-ray Films for Energies up to 3 Million Electron Volt.
9.1. Film speed
According to this standard X-ray film speed i s determined for the
density of 1.5 above the base and fog density. The speed of the film i s
taken as the reciprocal of exposure, measured in roentgens, necessary to
produce a density of 1.5-
In the present investigation only relative film speed densities were
determined and therefore they are given in arbitrary units.
Table 4. gives relative speeds (speed of Kodak Microtex film taken as
l .o) of X-ray films, calculated for direct exposures done without steel
filtration.
- 16 -
Table k. Relative film speeds (exposed without steel filtration)
Film
M
D2
D4
100
200
400
N
D2
D4
100
200
400
Intensifying screens
No screens
1.00
0.44
1.56
0.39
0-70
1.62
1.00
0.44
1.56
0.39
0.70
1.62
Lead screens
1+1 am
1.00
0.46
1.53
0.46
0.70
1.36
5.10
2.37
7.81
2.32
3-59
6.95
1.5+1.5 "•
1.00
0.46
1.20
0.51
0.61
1.28
4.43 2.07
5.39 2.30
2.74
5.77
Copper screens
1.5 + 1.5 ••
1.00
0.45
1.74
0.50
1.45
1.97
1.64
0.74
2.85
0.82
2.37 3.24
For X-ray films exposed through different thicknesses of steel
relative speeds have been calculated for density 1.5 in the middle of
each wedge thickness (i.e. behind 75i 125, 175 and 225 •» of steel).
The results of these calculations are shown in table 5«
- 17 -
From tables 3 and 5» the following relative intensification factors
can be computed in relation to films exposed with 1 + 1 mm Pb screens
(relative intensification factor l.o).
Table 5. Relative film speeds (exposed through steel)
Intensifying
screens
0.15+0.25Pb
1 + 1 Pb
I 4 I C 1
SKP 101
SMP 301
Steel
thickness
75
125
75
125
175
225
75
125
75
125
175
225
75
125
175
225
Film
H
0.66
1.33
1.0
1.0
1.0
1.0
0.41
0.85
1.55 1.44
1.66
2.00
2.66
2.40
2.56
3.33
D2
0.17
0.35
0.10
0.24
D4
1.07
2.60
0.68
1.30
-IB -
Table 6. Relative intensification factors
Film
Kodak Mi-
c r o t e x
S t r u c t u -
r i x B2
» D4
GAP 100
200
WO
S t e e l f i l t r a t i o n - • •
0 50-150
I n t e n s i f y i n g s c r e e n s
1.5+1-5P0
0 .88
0 .87
0 .69
0 . 8 6
0 .76
0 . 8 3
1.5+1.5CU
0 . 3 2
0 . 3 1
0 . 3 6
0 . 3 5
0 . 6 6
0 . 4 6
0.15+0.25PD
0 . 9 9
1+1 Cu
O.63
50-250
SHP 101
1.66
SHF 301
2 .74
In the above table mean values of film speeds were taken from table 5
(for the whole range of steel filtration).
9.2. Film contrast
R(W According to ASA standard PH 2.8 " the average film gradient is
defined as the slope of the straight line drawn on the characteristic
curve between the points corresponding to densities of o.5 and 2.5.
The average gradient : 2.0 log E 2 - log ^
where
E is the exposure corresponding to a density of 2*5, E. is the exposure
corresponding to a density of 0.5.
Following the above formula average gradients for different X-ray
film and screen combinations were computed and are shown in table 7.
- 19 -
Table 7. Average gradients of X-ray films
I n t e n s i
fy ing
s c r e e n s
0
0.15+0.25P1
1 t 1 Pb
I . 5 + I . 5 P 0
1 + 1 Cu
1.5+1.5CU
SKP 101
SHP 301
S t e e l
t h i c k
nes s
0
75
125
0
75
125
175
225
0
75
125
0
75 125
175
225
75
125
175
225
F i l « brand
Kodak
Hicrotex
6 . 9 *
5.3O
l | . 5 *
6 . 9 *
! i .76
1..85
5 -76
<i.30
7 . 1 1
3 -95
<t.60
5 . 8 3
5 . 8 8
5 . 8 8
5 . 6 3
5 . 0 6
5 . 6 1
5 A 6
5 .66
<t.70
S t r u c t u r i x
D2
5 -39
k.Zl
3-77
6 . 3 3
6 . 0 0
<t.82
4 . 8 2
5-98
1*
6 . 6 6
1.. 68
7 -60
6 . 9 7
"..56
4 . 7 1
5 . 0 2
GAF
100
7.2<>
6 . 7 3
6 . 7 3
6 . 2 9
200
5 . 3 3
5 . 6 8
6 . 1 1
5.6*
".00
6 .89
5 .97
7 . 3 5
5 .26
The average gradient was calculated for E, and £, corresponding to
densities 3.5 and 1.5 as most of the characteristic curves did not have
densities less than o*5*
lo. ATTENUATION IN STEEL
Attenuation of X-ray radiation from the accelerator nas measured
using "Super-Iricke" dosimeters. For that purpose the saae steel plates
were used as shown on fig. 4. The attenuation curve obtained fro« these
measurements is shown on fig. 29.
There per cent attenuation is given as well as the attenuation factor
k (reciprocal of the attenuation).
11. RADIOGRAPHIC HUGE CONTRAST
For X-ray films and intensifying screens and steel thickness ranges,
shown in table 1, radiographs of a slotted steel wedge were made. For
each slotted wedge (5o-loo; I00-I50; 150-200 and 2oo-25o mm) films were
exposed with different number of pulses so as to reach film densities be
tween 2 and 3 at both ends of the wedge. A U films were then developed in
an automatic film processing machine and film densities (up to 5) were
read on a 'IJuanta Log" Macbeth transmission densitometer.
The radiographs were read by two observers, and only such readings
were taken into account where both observers could see the same slot on
the radiograph. The radiograph of each slotted wedge was read along 11
lines, drawn through images of the holes drilled in the wedge. Thus it
was possible to assess the radiographs at different wedge depths (all
together V 1 11 = W depths, as shown in table 2).
From the assessment of visibility of slots of different depth on
wedge radiographs, diagrams were prepared, showing thickness ranges, in
which the particular slots could be seen on the radiographs, in function
of exposure (number of pulses) (similar to curves given in (<t) and ( 5 ) ) .
These diagrams are shown on figures 3o to 38. On these figures areas of
visibility of the five slots of different per cent depth are given.
From these diagrams, the following conclusions can be drawn. The
0.25a! slot was sometimes visible only on Kodak Mdcrotex film with 1 + 1 mm
Pb screens in the range from 50 to 2oo mm of steel. The visibility of the
deeper slots is given in table 8 for different steel thickness regions.
- 21 -
Table 8. Thickness regions in am of Fe of slot visibility on radiographs
Film and Screen
Combination
M 1+1 Pb
M SHP 101
K S MP 301
w. 0 . 1 5 + 0 . 2 5 Pb
M 1+1 Cu
D2 0 . 1 5 + 0 . 2 5 Pb
D2 1+1 Cu
D4 0 . 1 5 + 0 . 2 5 Pb
D4 1+1 Cu
Per Cent S l o t Depth
0 . 5
54-21(6
54-229
54-225
L04-146
L07-146
104-11*6
L04-146
L04-141
LOlt-llH
1
III
5 4 - 1 «
54-11*6
54-146
54-146
54-146
54-146
2 III 54-146
54-146
54-146
54-146
54-146
54-146
5
III
54-146
54-146
54-146
54-146
54-146
54-146
From the diagrams (figs. 30 to 38) one can see that for increasing
slot depth the latitude of exposure increases for the same slot depth
visibility.
Results quoted in table 8 cannot give a final answer to the question
which X-ray film and screen combination will give the best radiographic
image contrast. Therefore the radiographs of the slotted wedges were
further investigated by means of a scanning densitometer (seen on fig. 39).
Bach radiograph was scanned along U lines on each radiograph (at different
wedge thicknesses - see table 2) and densitometer readings were recorded
by a paper chart recorder. From the results obtained during these trans
verse scans absolute and relative increases in film densities could be
measured and calculated for different per cent depths of the slots. The
results of the above are given in table 9.
From table 9 the following conclusions can be drawn. Kodak Microtex
film with 1 + 1 mm Pb screens gives the best radiographic image contrast.
especially in the region of greater steel thicknesses (above 15o mm),
where the application of accelerator radiography presents most advantages.
The fluorometalic intensifying screens give very good results (even better
than lead screens) in the region up to 15o mm Fe. Above this thickness
they are poorer than lead.
lA
d
* f t
Aj
lA
s <
4
a
o <
a <
a
a <
a
<
<
o
ram
Fe
!
* L
r A l A O KN C*- AJ l A r H
O W r l r t
n - a - t y AJ O O O O
o o o d
rA i A t y vo 4 0 1 0 0
H AJ r-t Aj
O rH H H
J - O f t I O
H t y fy AJ
0.03
0.
03
0.05
0.
04
-d- lA-d-NC rH VO H O
AJ H ry AJ
\ f l f f l f t J J -O ry rA-3-
ry rA j - i A
IA AJ O ON Cv O rH O O
d d d d AJ t A O - d - , riOrlO
H O - * - * O ONVO n j
IA Cv ON CO
IA IAONVO O H H H
6 6 6 o Cv O O IA O VO O ON
r H r l f t J H
50-1
00
100-
150
150-
100
20
0-25
0
1+1
Pb
s
rH O ON CV fy rH 00 IV
ri ri ri O
IA Al t A - * H - * rH O O O O
0 0 d 0
O v o l A O l A O O O
(A ri AJ AJ
- * O OOO I A j - ON CV
Al A l rH ri
ON lAVO A l
O O O O
O O O O
-± ry oco vo 0 0 0
rA ry r A H
O - J - i A ON H Al Cv ru
i A rA ry r y
-a- i A r A i A r A - a -O O O O
d d d d 00 ONco AJ
O O O O
H H H AJ
-a- rno cv V0 H v O J -
I A 0 0 C v \ 0 CO
VO IA IA AJ O H H rH
O O O O
l A O l A t O O ON O 0>
H H Al H
50-1
00
100-
150
15
0-20
0
200-
250
CO H
•s
OO CvvO I A -a- H O ON
ri ri ri ri
H V O I A l A I A r H - a -
0 0 0 0
d d d d CO ØN-vo vo
0 o-a- 0 AJ l A r H AT
AJCO AJ fjs
AJ O ry j -
r y I A H H
\ 0 \ 0 l A H - a r - a -O H O O
do d d J - O AJOO H IAO0 O
AJ K \ r A r A
H J - VD AJ
vo -a - 0 0
AJ i A r A AJ
0.0
56
0.11
0.
115
0.06
-a- cv cv cv
H H N O
ry i A I A I A
H C O O M A lA-a-oO Cv
VO00 Cv i A
VO IA1ACO O H rH O
O O O O
•ACvoO AJ O IACO IA
ri ri ri r-\
50-1
00
100-
150
15
0-20
0
200-
250
£3
3:
0.82
0.
77
O.0
3 0.
019
3.62
2.
48
1.22
1.7
1
* * 6 6
3.68
2.
57
1.5
4
2.0
5 0.1
6
0.04
I.
07
2.08
3.0
3
5.27
0.
03
0.1
05
1.0
3
1.9
9
50-1
00
100-
150
+ .0 p*
H o j
d d
X
0.8
97
0.9
9 0.0
11
0.0
1
1.20
1.
04
1.42
1.
72
0.0
38
0
.04
3
2.71
2
.47
2.33
2
.94
0.0
38
0.0
88
1.
62
2.96
4.
57
7.1
9
0.0
95
0
.20
5
2.08
2.
85
50-1
00
100-
150
1+1
Cu
s:
0.6
9 0.
67
0.01
7 0.
010
2.37
1.5
6
1.10
2.
17
0.0
2 0.
07
1.77
3.
06
1.87
2.
40
0.0
33
0.
07
1.76
3.
04
3.99
6.
53
0.09
0.1
9
2.25
2.9
1
50-1
00
100-
150
0.1
5 +
0.
25 P
b
Od
Q
0.66
1.
77
0.01
8
0.01
9 2.
68
1.2
1
1.50
2.
30
0.0
57
0
.02
9 3.
72
1.24
1.
81
3.44
00 o j v o - d -O 0
od
3.7
9
1.24
3.3
3
6.99
0.0
7
0.0
86
2.
17
1.22
50
-100
10
0-15
0
1+1
Cu
1
o j
AA 66
0.01
7 0
.00
8
3.26
1.
64
0.94
1.
28
0.0
2 0
.04
6
o j \ o
OJ K\
1.6
3
1.94
0.
021
0.06
t N 0 -OJ O
00 o j C^ 0J
0.08
0.
08
2.1
3
1.6
3
50-1
00
100-
150
0.1
5 +
0.
25 P
b
VOVO
O O
0.01
3 0.
016
1.86
2.
50
1.23
1.
98
0.0
36
0.0
5 2.
90
2.54
^ 3 o O ^
0.0
75
0.0
35
2.
88
1.10
5.
06
8.5
1
0.11
0.
09
2.23
1.
10
50-1
00
100-
150
1+1
Cu
- 2 3 -
Another advantage of the flour ran tul i c screens i s the shortening of exposure tine* In comparison with the 1 + 1 am Pb screens exposure can be cut down to 5o< with SMP lo l and to 330* with SMP 3ol screens.
12. EADICGRAWIC DUGE QUAIJTT
Hie assessment of the radiographic iJBage quality was done by the ISO wire IQI's. For that purpose steel wire 1IS07 and 6IS012 IQI's were used having the following wire diameters.
Table 1 a Wire diameters of the ISO IQI's
IQI
1IS07
IQI
61S012
Wire number Wire diaaeter-mm
Vire number
Wire diameter-ma
1
3.20
6
2
2.50
7
1.00 0.80
j
2.00
8
0.63
4
1.60
9
0.50
5 1.25
10
0.40
6 1.00
11
0.32
7
0.80
12
0.25
Fig. ito gives the per cent IQI sensitivity for steel thicknessee
from 50 to 25o BID for IQI's from table l o .
The above mentioned indicators were placed in front of the steel plates (on the source side) of different thicknesses, and vires of minim« diameter seen on the radiographs were read by two observers, and only such readings were taken into account where both observers could see the same wire.
The IQI sensitivity was checked several times using different X-ray film and screen combinations« During these checks different film dens i t ies were obtained. The results are shown on figs, kl to W*
Table 11 gives film densities obtained during these investigations.
- 24 -
Table 11. Film densities during radiographic image quality investigations
S t e e l t h i c k n e s s - mm [ 50
Fi lm
GAF 100
GAF 300
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
M
GAF 100
GAF 200
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
M
S c r e e n s
1+1 Pb
1+1 Pb
1.5+1-5 PI
1 .5+1-5 PI
F ig .No
41
42
43
44
1 .86
2 . 2 7
2 . 7 6
2 . 6 8
1 .30
1 .32
1 .25
3 . 2 2
1 .40
1 .75
1 .45
i . 8 o
i . 8 o
2 . 1 5
1 .75
1.96
2 . 1 4
5 .07
2 . 4 1
100
1.82
2 . 1 7
2 .62
2 . 3 5
1.24
1.34
1.19
2 . 8 4
1 .33
1.50
1 .45
1 .80
2 . 0 0
1.95
1 .95
1.96
2 . 0 7
3 .38
2 .16
150
1.79
1.82
2 . 2 8
1.52
1 .59
0 . 9 5
2 . 7 4
1 .48
1 .50
1 .75
1 .65
2 . 0 0
2 . 1 5
1 .9
2 . 5 0
2 . 8 7
2 .34
200
2 . 2 9
2 - 3 5
3 . 0 4
1 .58
1 .48
0 . 7 7
2 . 4 1
1 .38
1 .55
2 . 0 0
1 .80
2 . 1 5
2 . 4 0
2 . 2 0
2 . 3 7
2 . 7 2
2 . 8 2
250
3 .59
3-48
4 . 8 6
1 .30
1-34
0 . 9 1
2 . 42
1.36 *
1 .80
1 .80
2 . 2 0
2 . 5 0
2 . 3 0
2 . 4 0
4 . 2 9
4 . 3 4
5 .94
- 25 -
Table 11 continued
S t e e l t h i c k n e s s - mm
Fi lm
GAF 100
GAF 200
GAF 400
D 2
D 4
M
GAF 100
GAF 200
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
K
D 2
D 4
H
M
D 2
D 4
S c r e e n s
1 . 5 + 1 . 5 Pb
1 . 5 + 1 . 5 Pb
1 .5+1 .5 Cu
F i g . No.
45
46
47
0 .15+0 .25Pb 48
1+1 Pb
1 . 5 + 1 . 5 Pb
1+1 Cu
1 .5+1 .5 Cu
SHP 101
SHP 301
1 + 1 Cu
48
48
50
1 .30
1 .84
2 . 4 2
4 . 9 4
2 . 0 3
1 .75
1 .45
1.84
2 . 4 2
2 . 1 5
2 . 0 3
2 . 4 8
2 . 6 9
2 . 1 9
3 - 3 3
1.92
2 . 4 5
4 . 3 8
> 5 . 0 0
4 . 8 0
3 . 5 0
4 . 1 7
> 5 . 0 0
> 5 . 0 0
4 . 2 5
4 . 0 0
4 . 5 2
4 . 6 8
100
1.38
1 .82
1 .21
3 . 1 0
1.56
1 .50
1 .45
1.82
2 . 0 0
1-95
1 .95
2 . 8 8
3 . 6 8
1 .85
2 . 8 1
3 . 8 0
3 . 1 6
4 . 1 2
4 . 3 8
4 . 1 8
3 .16
3 -70
4 . 3 5
4 . 2 2
4 . 2 5
3 . 1 7
4 . 0 0
3 -90
150
1 .50
1 .80
1 .23
3 . 5 2
1.36
1 .50
1 .75
1 .80
2 . 0 0
2 . 1 5
1 .90
2 . 8 8
3 -71
3 . 1 4
2 . 6 7
3 . 3 0
2 . 5 0
4 . 4 7
4 . 7 2
3 . 7 3
2 . 5 8
3 - 4 7
3 .56
3 -50
2 . 4 5
4 . 0 0
3 . 5 0
4.38
200
1 .65
1.64
0 .94
2 . 8 8
1.52
1 .65
2 . 0 0
1.80
2 . 1 5
2 . 4 0
2 . 2
2 . 3 8
3 .24
2 . 5 6
2 . 2 0
2 . 9 0
2 . 4 3
4 . 2 5
2 .4 2
4 . 6 4
3 . 3 0
5.14
2 . 4 3
2 . 8 3
250
1.08
1.39
1.07
2 .64
1.28
1.80
1.80
2 .26
2 . 5 0
2 . 6 4
2 . 4
2 .54
4 . 3 0
2 . 9 6
2 . 8 3
3.6O
3-32
> 5 . 0 0
2 . 7 5
4 . 7 8
3-92
>5 .00
3 . 4 0
4 . 2 2
- 26* -
1?. FIIM UNSHARPNESS
During some of the image quality investigations the IQI's were also
exposed directly on the cassette of the X-ray film, without any filtration
of steel. Thus the inherent film unsharpness could be determined by read
ing the diameter of the smallest wire of the IQI, which was visible in the
radiograph.
From fig. **9 the geometric unsharpness can be determined »-»King into
account that:
(y = 2o mm (focus size)
F = 2ooo mm (focus-film-distance)
d = 0.2^ mm (diameter of the thinnest wire)
c = 1.5 mm (thickness of the front side of the cassette)
s = 1.5 mm (largest thickness of the front intensifying screen)
This geometric unsharpness can be neglected because it is only 12.5#
of the diameter of the thinnest wire in the penetrameter (Mo. 12 - o.25 mm).
Therefore the minimum visible wire of the indicator will be the direct
measure of film unsharpness.
Table 12 gives the results of film unsharpness measurements, which
were made with three sets of ISO 101*6 1/7; 6/L2 and I0/I6.
Table 12. Film unsharpness
Film
GAF 100
GAF 200
GAF 400
D 2
D 4
M
Screens
1+1 Pb
Density
2.08
2.25
3.24
2.58
Minimum visible wire
No.
11
11
10
11
diameter - mm
0.32
0.32
0.40
0.32
Table 12 continued
Film
GAF 100
GAF 200
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4
M
GAF 100
GAF 200
GAF-400
D 2
D 4
H
GAF 100
GAF 200
GAF 400
D 2
D 4 M
Screens
1+1 Pb
1.5+1.5 Pb
1.5+1.5 Pb
1.5+1-5 Pb
1.5+1.5 PD
1.5+1.5 Cu
Density
I.56
1.44
1.27
2.94
1.22
1.10
1.30
1.40
1.65
2.20
1.80
2.20
2.37
3.39
2.42
1.58
1.42
1.40
4.17
1.58
1.58
1.30
1.40
1.65
2.20
1.80
2.98
2.40
1.86
2.75
1.68
2.46
Minimum visible wire
Ho.
10
9 10
11
10
10
11
10
11
11
11
10
11
11
11
9
10
9 10
11
9 11
10
11
11
11
11
12
11
12
11
11
diameter - mm
0.40
0.50
0.40
0.32
0.40
0.40
0.32
0.40
0.32
0.32
0.32
0.40
0.32
0.32
0.32
0.50
0.40
0.50
0.40
0.32
0.50
0.32
0.40
0.32 0.32 0.32
0.32 0.25 0.32 0.25
0.32 0.32
- 2 6 -
As can be seen all the films showed an. inherent unsharpness better (8)
than 0.32 mm. This value is quoted by Halmshaw for 2 MeV X-rays,
whereas for lo KeV X-rays 0.65 BB can be expected«
14. BCPGSURE CHARTS
From characteristic curves of X-ray films and intensifying screens
(see table 1) and the attenuation curve in steel (see fig. 29) exposure
charts were computed. Figs. 3o and 51 show the exposure charts for the
0.15 + o,25 an Pb-screens, and fig. 52 gives a comparison for Kodak Micro—
tex and Structurix D2 and D** films for density 3* On figs. 53 to 55 ex
posure charts for 1 + 1 mm Pb-screens are shown whereas fig:* 56 shows a
comparison for Kodak Microtex, Structurix D2 and lA and GAF loo, 2oo and
4oo films.
Similar exposure charts for 1.5 + 1.5 mm Pb-screens are shown on
figs. 57 to 60. Figs. 6l to 63 give the exposure charts for the 1 + 1 am
Cu-screens, and figs. Sk to 6? for the 1*5 + 1*5 mm Cu-screens.
In the way described above (characteristic curves taken without steel
filtration + attenuation curve in steel) exposure charts for 1 + 1 ma Pb;
1.5 + 1*5 nm Pb; 1.5 + 1*5 am Cu-screens were computed whereas exposure
charts for the 0.15 + o.25 mm Pb; 1 + 1 mm Cu, SHP lol; SMP 30I screens
were computed directly from characteristic curves taken directly through
different filtration of steel (see figs. 2o and 22 to 28).
A comparison between the two methods of computing exposure charts are
made for Kodak Microtex film exposed with 1 + 1 mm Pb-screen and shows
good agreement between these two methods. For that purpose figs. 53 and
68 were used (fig. 68 is taken from ( 9 ) ) .
From the exposure charts, one will see that exposure times were very
short. For 25o mm of steel and film density of 3 X-ray films used with
the faster fluorometalxc screens needed an exposure of only 2.5 min.,
whereas for the slower films (Structurix 1)2 or GAF loo) an exposure of
about 15 min. is needed.
- 29 -
15. SUMMARY OF CONCLUSIONS
From the investigations described the following conclusions can be
drawn:
1) It has been proved that radiography of steel up to 25o mm with the
Rise lo MeV linear accelerator is feasible with relatively short ex
posure times.
2) The investigations have shown that a good radiographic image contract
can be obtained (o.5$K
3) To reach better radiographic image quality (as judged by the use of
image quality indicators) it is essential to have a smaller focus for
the production of X-rays. This is possible, but at the cost of ex
tending exposure times. An attempt will be made in the future to
foculize the electron beam on the Bremsstrahlung converter to such an
extent, that good IQI sensitivity is obtained.
k) From the point of view of radiographic image contrast Kodak Microtex
film witn 1 + 1 mm Pb screens gives best results in thicker steel
sections (above 15o mm). In the region from 5° to 15o mm Fe fluoro-
metalic screens give even better radiographic contrast and at the same
time reduce exposure time.
5) From the point of view of radiographic image quality (as judged by the
wire IQI), thick lead screens (1 + 1 or 1.5 + 1.5 mm) with Kodak
Microtex film give the best results. Optimum sensitivity is reached
at about 15o mm Fe.
6) For the highest radiographic image contrast and quality, thick lead
screens present most advantages with a fine grain film like Kodak
Microtex. Such screens are comparatively cheap and easy to handle,
which is not true of e.g. tantalum screens, as advertised by several
investigators•
- 3° -
16. DEFERENCES
1. Brynjolfsson, A., Thaarup, G., Determination of Beam Parameters and
Measurements of Dose Distribution in Materials Irradiated by Electrons
in the Range of 6 MeV to 1<» MeV. Rise Report No. 53. 1963.
2. Hansen, Johnny, A lo NeV Bremsstraolung Converter. Rise Report M-1261
ISBN 87 55° oo6U 9, 1971.
3* Sehested, K., in: Hanual on Radiation Dosimetry. Edited by Holm, N.W.
and Berry, R.J., Marcel Dekker, New fork, 1976.
km Iaurence, G.C., Ball, L.W. and Archibald, V.J., National Research
Council of Canada Bulletin, 19^2.
5* Johns, H.E. and Garret, C : Sensitivity and Exposure Graphs for
Radiun Radiography. Non-Destructive Testing. Vinter 19*i9-5o» PP* 16-
6. Domanus, J. and Osuchowski, B.: A Comparative Method of Investigation
for Optimum Conditions in Radiography by Means of a Slotted Hedge (in
Polish). The Problem Sessions Series of the Polish Academy of Sciences.
XXVI. WrocXaw-Varszawa-Krakew, 1965.
7. American Standards Association. ASA. PH2.8-1964. American Standard
Method for the Sensitometry of Industrial X-ray Films for Energies up
to 3 Million Electron Volts.
8. Halmshaw, R«, Industrial Radiology Techniques. Vykeham Publications
(London), Ltd., 1971.
9. Domanus, J«, Analysis of Exposure Factors Influencing the Image
Quality in Linear Accelerator Radiography. Rise-M-1579* 1973*
8 tu
~ K -
A)|SIM}U| »A!W>1«8
Fig. 2. Intensity distribution in the X-«ay beam.
•m
250
.
- ^
300 m
^_____^
900 . —1
- 300 »
—uoo
p—-• 300
1
.
J
S
1
m f 1.25 2.5 5,0 12.«
é%
— X * i
0.120 0.20 Of 1.0 »
Pig. 5- Construction of the slotted steel wedge.
V *
36
Fig. 8. Slatted steel wedge surrounded with masking plates.
Fig. 9.
- 37 -
IF i i t t • K 11 11 m y Kil U P S P ^ • * -
Assembled steel blok with slotted
1 ' 1 ;*"v
\"
wedge.
- 38 -
• — • : - a — —
• i i i
Q oo tø NJ CM ' i i i i
3 co o> *r cg c r r
•
• ^ ^ ^
? OD t ø "X CM C 3 a> u> *» oi C
11
11
i i
i i
• i
i 1
11
11
* w ~ ^ w \ V \ \
\ N » -\ N 1
X N V X N \
\ \ l
; to iø c «
Fig. 10. Characteristic curves (no filtration) for Kodak Microtex
films.
- 59 -
CM O
1 1 1 1
~-~^Z^- -
•
1 • * ^ ™ * " * •**
TI
II
f i
r i
i i
i i
i i
11
TT
TT
TT
"J-
1 —
"
• i i i O co tf) >T CM Q CO ( Ø - f f C M Q a t Ø N T C N Q O D t Ø - i f N C in •<» <n c4 ~
NX \\ -\ x V" \ \ V \ \ V \ \ V vi VI
• I I I CD tf <f N
Fig. 11. Characteristic curves (no filtration) for Structurix
D 2 films.
• in -
a
I 1 1 1
P CD tD •* CM <• D -»
i 1 1 1 ? CD <0 -T CM C
•
i i i i > ao tp ** c* c i c
^ " ' N t *
? 4D (ø <f N C 4 *"
-
11
1 1 1
1—1—
1
J L
1
1 1
1 1
1
" \ \ \ ^ \ \ -
eo $£> - * CM
Fig. 12. Characteristic curves (no filtration) for Structurix
D >t films.
• M •
——^~~
~!&££m
', G
AF
o co to
100
•tf CM <
•
3 < D i D < t n Q g S | p 4 ( N ( * n t
} (0 |0 < N C
-
1 1
J.U
J.
-
1 1 1 1 1 T
T
" 1
N> \ 1-X^ \ \-V* \ r \ \ \V-
\ M I \\\f
i i i i
CO V> • * W
Fig. 13« Characteristic curves (no filtration) for GAF 100 films.
- "* -
O (O (O 4 n P (D i O 4 N O O i O 4 N q O ( O 4 N 2 < D l 0 ui •>» p> w "^
FIR. I1*. Character is t ic curves (no f i l t r a t i o n ) for GAF 200 films.
- * » 3 -
~ ^ - — 2 - — . _
-2ast§i
,
: G
AF
Q ø v tn
O
o
. - . i — j . „
— " * * — • • • . -
• i i i
•
i i
i i
i ii
i
11 i i i i—
i 1
i i
11
-
-
/ 1
/ /
i i i
il
111
( O | D < f ( M Q 0 S ( D 4 N C <D ID • * W
Fig. 15. Characteristic curves (no filtration) for GAF <t00 films.
. M* •
Fig. 16. Characteristic curves (no filtration) without intensifying
screens.
4 5 -
Q 00 <0 •* CM O O tf 3 W Q «D (0 5 Ol g • «0 •* t*
Fig. 17. Characteristic curves (no filtration) with 1+1 mm Pb screens.
-46-
Jg
m _l I L_ -I L.
g eo 10 »i <x P a> e < ) n p « S 4 N S « ( i 4 i i J c e ' i i )
Fig. 18. Characteristic curves (no filtration) with 1.5+1*5 mm Pb screens.
-*7-
Fig. 19. Characteristic curves (no filtration) with 1.5+1.5 mm Cu screens
48-
Fig. 20, Characteristic curves (through 50-150 nun Fe) for Kodak
Microtex films with 0,15+0.25 Pb screens.
•49-
O OD (0 -X O* P CO (0 *tf C M P CB |0 4 IN Q O ( 0 ^ M g * «* irt « * <** f*
Fig, 21. Characteristic curves (through 50-250 mm Fe) for Kodak Microtex
films with 1+1 mm Pb screens.
5o - 51-
g • <D •» « g o> ID <
Fig. 22. Characteristic curves (through 50-150 nm Fe) for Kodak Microtex
films with 1+1 mm Cu screens.
. . , | . , , , | , i i i i i i i i i i
0> ( 0 »* <* Q •> (0 <* N Q O? > U 4 n q « i g 4 « 3 c a ' '
Pig. 23. Characteristic curves (through 50-250 aa Fe) for Kodak Microtex
films with S KP 101 screens.
52- - 53-
Fig. PM. Characteristic curves (through 50-250 nm Fe) for Kodak Hicrotex
films with SMP 501 screens.
s • «. * " s - * * « Fig. 25. Characteristic curves (through 50-150 •* Fe) for Structurix D 2
films with 0.15+0.25 mm P* screens.
- 5 * - • 55 -
o s ID 4 N Q o <o •» ex P o» io >» « 9 <Å «tf •"» » ^
O ^* ex g CD «p < ex. ^
Fig. 26. Characterietic curves (through 50-150 mm Fe) for Structurix D 2
films with 1+1 mm Cu screene*
Fig. 27. Characteristic curves (through 50-150 am Fe) for Structurix
D if films with 0.15+0.25 nm Pt> screens.
10' 57 •
Fig. 28. Characteristic curves (through 50-150 mm Fe) for Structurix
D *f films with 1+1 Cu screens.
10'
10l
10
k
V.
10J
10
10'
10" 50 100 150 200 250mmFe
Fig, 2Q. Attenuation curve in steel.
- 5 8 -
250
g 10 20 30 LO 5 0 60 70 80 9 0 ^ 0 <° 2 0 3 0 4°1506 0 7 0 8 0 9 0 2 0 0 1 0 2 0 3 0 *° 250 mm Fe
Fir- 30- Visibility of slotted wedge on Kodak M film with 1+1 mm Pb screens.
59 •
- 0 , 0 2 0 3 0 40 go 60 70 80 90,0010 2 0 3 0 4° ) 5o60 ™ 80 90 20010 20 30 40 rø mm F*
Fig. 31. Viaibility of slotted wedge on Kodak M filme with
SHP 101 screens.
- 6o -
g 10 20 30 40 50 60 70 80 90JQQ10 20 30 4 0 1 5 Q 6 0 70 80 90 20010 2 0 3 0 *°250
mm Fe
V'w. y?. Visibility of slotted wedge on Kodak H films with
KKP 301 screens.
- 6 1 -
0 10 20 30 40 gø 60 70 80 9 0 1 0 Q 1 0 20 30 40,5(560 70 80 90 200'0 20 3 0 4 0 2 5 0 • mmFe
Fig. 33. Visibility of slotted wedge on Kodak « films with
0.15+0.25 mm Pb screens.
6 2 •
250
0 10 20 30 40 5 0 60 70 80 90,0 ( )10 20 30 4 0 ^ 6 0 70 80 90 2'o010 2 0 3 0 *°250 mm Fe
Fi/'. V K Visibility of slotted wedge on Kodak M films with
1+1 mm Cu screens.
- 6 3 -
10;
10'
r
10'
50
- r -100 150 200 250
D2 0.15+0.25 Pb
5%D
0 5 % | |
J I L. )p ,_ r 0 » 20 30 40 g'o 60 70 80 90 j 0 0 10 20 30 40 ) f;060 70 60 90 200'0 2 0 3 0 *°250 .
* mm Ft
fig. 35- Visibility of slotted wedge on Structurix D 2 filM with
0.15+0.25 na Pb screens.
(A
250
0 10 20 30 40 gø 60 70 80 9 0 1 0 Q 1 0 20 30 4 0 ^ 6 0 70 80 90 20010 2 0 3 0 *° 250 mtnFe
:'\r,. ~tf>. V i s i b i l i t y of s l o t t e d wedge on S t r u c t u r i x D 2 f i l m s with
1+1 mm Cu s c r e e n s .
- 6 5 -
10!
10'
« "3 Q.10-E
10'
101
50 100 150 200 250
DA 0.15+0.25 Pb
J L_ l L. _l [_
5%n
0 . 5 % | |
i i i i_ 0 10 20 30 40 50 60 70 80 9 0 1 0 Q 1 0 20 30 40 1 5 060 70 80 90 20010 2 0 3 0 *°250\
mmFe
Pig. 37. Vis ib i l i ty of slotted wedge on Stmcturix D 4 films with
0.15+0.25 mm Pb screens.
- 6 6 •
50 100 150 200 250
D4 1+1Cu
J L. - I I L_ l_
5%n
0 . 5 % | |
I I I I - I l _ _ l _ 0 10 20 30 40 5 0 60 70 80 9 0 1 0 Q 1 0 20 30 40 1 5 0 60 70 80 90 2001 0 20 3 0 *°250
mmFe
Fig. 38. Visibility of slotted wedge on Structurix D <J films
with 1+1 mm Cu screens.
C7 •
Fig. 39. Scanning densitometer.
~>
"3> c Ol 0)
c *> o
50 mm
lOOmm
I50mm
200mm 250mm
IO N n ^ l f l S t O O N V O H I M l
Fig. kO. Per cent IQI sens i t i v i ty .
•/.
£ *+
^ Ot (o | s 10 u
2
o
CM
O
O
o < o
GA
F 20
0 -
GA
F 1
00
1 1
) <« n N . i i i
*"
- 6 9 -
- *7 0 * « f * c o i n - * « n e M o i i i i •
> ^
— —
.«--
— ^ s - - -*^
I — 1 — 1 — 1 —
1 1 1 1
„25
0
C O
c
in
,nZ5
0
S!
i in
S
t
n'5
0o
in
o
C
m'5
0,
O
o esi
C
n'5
°7
5
•n
S ,N
S
a s
o o
— o ø> <ø .p- *© m
Fig. 4l. IQI sensitivities for 1+1 mm Pb screens.
to tn »c co CM
- Vo -o — o 9 r*
1
o
CM
O
O O
u. < o
GA
F 20
0 -
GA
F 1
0U
i i
'
— i — i i -i—
^
N \
__^~——' '
n •**
__| ' ' '
1 1 1 1
/
y
N } J
'^N, /
S*
I I I !
1 1 1 1 1
— 1 l _ l 1
O
CM C
c O
c
o in
o CM
C c
O
c
in
o CM
C
„15
0,
S
m
S 1
,«1
50
, m
o CM
C
n1
50
,
m
o in
c
n'5
0„
: :
to in sj co CM r* <ø in . * m CM
FIR. h?. IQI s ens i t i v i t i e s for 1+1 mm Pb screens.
/I Q
f£f4 Ok 00 C«- tO U
SP
b
i
<
s
o
CM
o
o . o
< o
GA
F 20
0 -
GA
F 1
00
) «» n N ^ -1 l 1 i
* O* « c (O »o » co CM 3 1 1 1 1
V \ , , ^
" ^
\
\
y
j J ->r
^ " - " /
V
^N y
i i i r
9 o> CB r*> u> ih sr r» CM ^ o oi e > IØ iA 4 co CM «-
o CM
O
CM
O
o
in
o m CM
O
CM O
O
in
o CM
O CM
O in
o
i n l
o
CM
O IM
O in o
o
o in CM
O
CM O
o
o m
o m
s CM
O
"s e
Fig. <*3. IQI sensitivities for 1.5+1.5 nm Pb screens.
- 7 2 •
^ oi co t> tø u i
Q
CM
O
GA
FA
OO
G
AF
20
0 -
GA
F
100
: i
i i
i • * n o j . - • 1 1 1 >
" u - -
-' o> ce c^ o « l 1 1 i
" X
-
} z ^ M
1 • ' •
» -tf O CM o
1 i • •
O
CN
8 CM
O ttl
O
o in
o Ol
O
CM O
O
o i n
o CM
O
CM O m
Q
O
» , O
CM O
CM O m
o
o
o CM
O CM
O
O
u>
o in CM
CM
O
o
co »fl sr n c M t — O c n a > r < » < ø m « ? f * } C M « —
TQI Gensi t ivi t ies for 1.5+1*5 mm P*> screens.
73 -
- 1 .
2
o
CM
O
GA
F A
OO
G
AF
20
0 -
GA
F
100
3 C* (O U
1 1
J < n N . t .
~ 1 — -1 1 1 "
^ ^
______r '
____—-—'
n .
^
- H -
e» <o t*> co u —1- I " ! 1
*x /
K
' s J
y
\ )
y
~ \ \
/
- ^ u
7 * /
• i i i
^ -» en CM ^ 1 1 ! 1
c c
c
c L
< C
<
. < < <
• <
•
<
< L f
C
c u
c V
c
C
1 I I 1 le <n CM r- o a> tn *M . -
- ' - O o P^ O U
2
Q
CM
O
O O •
l i .
<
GA
F 2
00
- G
AF
100
i i 1 -c n rj _ w
. i ,,,..,.1 _,—
" " ' .
•
^
O CD C* <D *
1 1 I i
\ \
^
N
y
\
r S
" " • ^ u
/
s
n ^ co <M o
-
s c*
S "s
S \ S i!
S o
S
•fe CM
s y
O <
»»
s! ~s
CM
g 2
S "8 S *S o H
.
s s 5
S g S
« - lf\
I f l ID ^ O (M ^ p O ) 0 0 f * - ( O l i O ^ « * > * • —
- 7 5 -
:
3
-*?
: r » a>
2
•tf
o
CM
GA
F 40
0 G
AF
200
- G
AF
100
o> co
CO js . tø
1 1 r* tø m
» MT «"» CM ^
• j n IN ^ o
P
^
^
Ok
i ! —i—r-
N
.
S. 3 ^ A-
\ /
^
J /
co 'r* to in
T — 1 — 1 — r ~
I" - 5 S
- i - i !
* S
2
S
a o
ft h* S
S
• E
° F
~s I-s !£!
" = ir>
S "g => i' o
• o
m
o
CM
s CM
O
. o
m
MT rn <N p-
7. 2.5
2.0
1.5
1.0
05
M x-0.15+0.25 Pb — O-1 + l Pb — — • -
5
1.5+
fc, V
0 «
1.5 P
,
S
» 1 !
b -
) i 30 21
/
» 2
;
50
M x-1 +1 Cu — — 0-15+1.5CU — —
5
[
\
\
OK
<
X) 1«
\
50 21
i
'/
M2!
i
30
M x-SMP 101 O-SMP301
<
:
S
w .
s t o
%
,3> o
0 100 150 200 250
02 x-0.15«O25Pb— 0 - 1 + 1Cu —
i
\ —<
** ^~
i
50 100 150
DA x-QJ5*025Pb— O - 1 + I C u — —
\
V V i \ \ \ \
N>
i
50 100 150 mm Fe
Fig,^8 • IQI sensitivities for different film- screen combinations
- 7 8 -
10O 150 mm
Fig.50. Exposure charts for Kodak MwithO,15 + 0.25 mm Pb screens
- 79 -
4
3
2
1.5
io9< a 7 6 5
4
3
1.5
io93
7 6 5
4
3
2
1.5
in2
D2
z.
~ -D4 --
0.15* 0.25 Pb -
-
-
10 min
5-min-
2 min
1.5 min
lmin 50s
25s 20s
15s
10s
5s
0=2
0=3
0=2
50 100 150 mm
Fig.51. Exposure charts for Structurix D2 ana Dk with 0.15 + 0.25 «™ Pb screens
- 8 o -
10 min
5-min-D=3
D=3
150 mm
Fig, 52. Comparison of exposure charts from f igs . 50 and 51
- 8 1 -
9 s 7 6 5
i
3
2
1.5
10' 9 e 7 6 5
t
3
2
1.5
103
I 7 6 5
4
3
2
1.5
'o,2
s 7 6
10'
-
S 3 a
-/ /
M U1 Pb
/ / / / ' /'
/ / SS s'
's^S SS s'
^** ^** s\^-. /
—
-D=3
D=2
" " -
" -
1. s
l li)
" -50 100 150 200 250 mm Fe
Fig.53« Exposure charts for Kodak M with 1 + 1 mm Pb screens
- 82 -
5 10' 250mm Fe
Tig.5k. Exposure charts for Stucturix D2 and D^ with 1 + 1 mm Pb screens
- 8 3 -
IOV 9 " 8 -7 -6 -
5 10'
7 -6 -
¥
y
GAF H1Pb
: ^ p y
/
/
100
200
/
y
> r ^
400
50 100 150 200 250mmFe
fig-55- Exposure charts for SAP films with 1 + 1 mm Pb screens
- 8 * t -
1CS
c
5-10'
-
-
---
-" ---
_ « 3 Q
"b
-
-
1*1 Fb
Jsyté
$2?
•p/\ ' ^ ^
•>-»
^ s * * * ^ 0 " 3 t* i
c=a 3=3 D=3
-
.
1-xp
osur
e
UJ
50 100 150 200 250mm Fe
Fig.56. Comparison of exposure charts from f igs . 53 to 55
- 8 5 -
10* I
1.5
10'
1.5
103
15
10/
• in'
-
ses
3 a
-F
M 15+1.5Pb
^Ss^" S^S*'^
SS Ss
S'S SS
SS / , '
/ ' '
-
1 1
1 1
1
• . -
• •
-
D=3
D=2
--
_
i s
Ex p
c
-
50 100 150 200 250 mm Fe
Fig.57. Exposure char ts for Kodak K with 1.5 + 1-5 """ P* screens
- 86 -
1 7 i
5 L
3
2
10' 9 e 7 i 5
l
3
2
1.5
,«1 Ur
9 8
6 5
l
3
2
1.5
102
9 8 7 6
10'
I
----
_
S -—
3 • i
^
•
.
1.5+15Pb
/ / / / '
./' y * ^r
/ / ' ,/'
02
y/l,'
, / ' . * j ^ ^
/ / S *
/
yT s
yS S
' ' ^S
04 s'^y' ur . ^
'1/ é*
^sS0^ .+ ^>r ^<0>*^
y s'
^s^>
y'
D=3
D=2
D=3
D=2
-
--
1-i 1-u
" -
20 min
I5min
10 min
5 min
2min
1.5 min
Imin 50s
2Ss 20s
50 100 150 200
S- 10s
5s
2.5s 25
1.5s
250mmFe
Fig,58. Exposure charts for Structurix D2 and n't with 1.5 + 1,5 mm Pb screens
- 8 7 -
9 8 7 6 5 t
3
2
1.5
10' 9 8 7 6 5
2
1.5
103
I 7 6 5 (
.3
2
1.5
if 8 7 6
in'
æ 3 a - £
GAF 15*15 Pb
.-•
-
j^p1^ ^*^^*
^ 7 ^ ^<K ^ ^O^ 100 . ^ ^ » ^ ^ "
• O > v^> > ; / • •
fe^r -y ' /
--_.
--
*
y^Z^" s^y' y'.
°=3 0=3 D=2 D=2
D=3 D=2
-
-
i me
1 1
1 ..1
. ir
et
1 a. UJ
_
-50 100 150 200 250 mm Fe
Fig,59. Exposure charts for QAF film's with 1.5 + 1-5 ""» Pb
9 8 7 6 5
3
2
1.5
o' 9 B 7 6
5
4
3
2
1.5
O3
9 S 7 6 5
4
3
2
1.5
O2 U9 8 7 6
n'
----
-
--
--" -
s - in
a "E
•S *\i
s • ~ s t ~ ~
z -U
1.5+1.5 Fb
y
sT y ^
yy^ s *y y% ^ Ssr
yC-y yyr y ^
^ y^
^y
yw y/y^
' /it y y ^
y ^ 'yy y
y^. ~y^r
^y^^^y^
j i ^ ^ s
° k < ^ ^y^^
t®
^ ^
y^s***^ <r
^y^^ J ^ ^ \ J > ^ ^ ^ ' ^
^s^s^^ ^
0=3 D=J Efc3
n j
3=3
-
-
Of
. i -os
ure
-•
-
20 min
1 5 m i n
10 min
5 min
2 m i n
1.5min
I m i n
50 s
25 s
20 s
15s
•S- 10s
5s
50 100 150 200
2.5s 2s
1.5s
250 mm Fe
Fig.60. Comparison of exposure charts from figs.57 to 59
4
3
2
1.5
e 7 6 5
4
3
2
1.5
H3
7 6 5
4
3
2
1.5
in2
-. -
•
-
---
M 1 + ICu
-
-
-
_
10 min
5 min
2 min
1.5 min
Imin 50s
25s 20s
15s
10s
5s
50 100 150 mm
F i g . 6 1 . Exposure c h a r t s f o r Kodak M w i a 1 + 1 mm Cu screens
- 9o -
4
2
IS
8 7 6
5
i.
3
1.5
°93
8 7 b
5
3
2
1.5
n2
-
_
D2
DA
-
1+1Cu
-
-
-
"10 min
5 min
2 min
Imin .50 s
25s 20s
15s
10s
5s
D=2
50 100 150 m m
Fig.62. Exposure charts for Structurix D2 and Dk with 1 + 1 mm Cu screens
- n -
0=3
150 mm
Fig.63. Comparison of exposure charts fro» f igs . 61 and 62
-92 -
I U ' 9 8 7 6
i
3
2
1.5
10' 9 8 7 6
L
3
2
1.5
I03
9 8 7 6 5
t
. 3
2
t.5
KJ* 9 8 7 6
in'
I
-
.
S . J/l
3 0 • E
k
"
--•
M 1.5+1.5CU
/ /
/ / ' / '
s ' s
/ / '
. / '
y//S''
/V s'
^*s^^ S^ y^' S'
D=3
D=2
-
-
-" ~
-
i-os
ure
. •
50 100 150 200 250 m m Fe
Fig.64. Exposure charts for Kodak K with 1.5 + 1.5 mm Cu screens
9 3 -
7 •
5 •
5 •
2
15
1.5*1.5Cu
/ /
D2
D4
. - 0 = 2
r io.3-
/ /
y /
2 •
1.5 •
K 6 -
5i0' 50 100 150 200
Fig. 65. Exposure charts for Structurix D2 and Dlf with 1.5 + 1.5 mm Cu screens
' 20mln
• 15 min
' 10 min
• 0=2
5min"
• 2min
• 1.5 min
• Imin 50s
25 s 20s
15s
10s
i 5s
•2.5s
2s
• 1.5s
250 mm Fe
-9 1*-
5 10' ' 50 250 mm Fe
Fig.66. Exposure charts for OAF films with 1.5 + 1.5 mm Cu screens
- 9 5 -
M
10' I 7 6 5 & 3
2
IS
10' 9 8 7 6 5 I
3
2
1.5
t 7 8 5 1 3
2
1.5
8 7 6
5-0
a
1.5+1.5Cu
50 100
Fig.67* Comparison
—
JKx
"JSP
150
of exposure charts
200
froo f igs .
1=3
£
i X III
20 min
15min
10 min
5 min
2min
1.5 min
Imin 50s
25s 20s 15s
10s
5s
2.5s 2s
1.5s
250mm Fe
$k to 66
- s -
250 mm Fe
Fig.63. Exposure charts for Kodak M with 1 + 1 mm Pb and SMP 101 and SMP 301 screens