Elisa Rapisarda

Università degli Studi di CataniaUniversità degli Studi di Catania

Dottorato di Ricerca in FisicaDottorato di Ricerca in Fisica

Limit of existence of nuclei (location of the drip-lines and charge boundary of the heaviest elements)

Nuclear structure (halo nuclei, skins, new magic numbers)

Investigation of the EOS dependence on the isospin

Astrophysics (Nucleosintesi degli elementi pesanti, rp-process)

Nprod = NincNtarg12345

cross-section,

Ninc: primary-beam intensity,

Ntar: target thickness,

1: product release and transfer efficiency,

2: ion-source efficiency,

3: efficiency of the spectrometer,

4: efficiency due to radioactive decay losses,

5: post-accelerator efficiency.

Production Target

Q1,2

Test Point at the final focus

of the Fragment Separator

Test Point in Ciclope

EXCYTProduction Target

Fragment Separator

Test Point at the 20° line

27Al (100m)58Ni 40 AMeV

9Be (500m)

40Ar 40 AMeV12C 62 AMeV

20Ne 45 AMeV

Degrader

Q1 Q2 Q3

Q4 Q5 Q6

Q7 Q8 Q9D1

D2

Bersaglio di prod.

Bersaglio di produzione

Q1,2

filter the nuclei of interest from other fragment

collect as much as possible the nuclei of interest

Produce an achromatic image of the primary beam spot for further transport through other beam lines

ACHROMATIC: the total dispersion is zero

WHAT WE WANT

HOW TO DO IT2 optical section (a,b) symmetric to each other

The optic of the second section merely compensate the dispersion caused by the first

One-to-one image of the beam on target can be obtained at the final focus

B = P/q

filter the nuclei with the same A/q ratio for fully stripped ions: A2.5/Z1.5

preserve the achromaticity of the separator

WEDGE SHAPED

Thicker degrader at the high velocity side Thinner degrader at the lower velocitity side

BUT: the spectrometer can not separate nuclei with the same ratio A/q DEGRADE

R

dE/dx Z2/v2

TAGGING: the basic idea is to identify

event- by-event the produced ions with minor

modifications of their characteristics:

•Charge and mass identification (Z,A)

•Position Diagnostic (x,y)

•Energy E measurements

production yields MEASUREMENT

TRANSMISSION measurements up to

experimental areas

12C + 9Be(500m) a 62 AMeV (February 2001)

40Ar + 9Be(500m) a 40 AMeV (June 2002)

58Ni + 27Al(100m) a 40 AMeV (June 2002)

20Ne + 9Be(500m) a 45 AMeV (June 2004)

Possible with pulsed beams:106 ions/sec are distributed as one per

burst at 100 MHz (10 nsec) LNS-CS RF 15-50 MHz

Secondary Target

(ΔE,ToF) (x,y)

(x,y)

Si

P

P

A

C(A,Z), E

Secondary Ion

(ΔE,ToF)

Si-Strip 1616

OR

Plastic ScintillatorPlastic Scintillator2.5x2.5cm2.5x2.5cm22

(rate: >10(rate: >1055))

Si(300μm)Si(300μm)3x3cm3x3cm22

(rate: >10(rate: >1055))

PPACPPAC

4x4cm4x4cm22

(rate:10(rate:1044))

ENERGY

DIRECTION

INTENSITY

ION CHARACTERISTIC

S MODIFICATIONS

energy loss

straggling

reactions

PERFORMANCE: up to Z=70 for intermediate energy primary beam (30-40 MeV/u)

RESOLUTION: 0.6 %

ES

i (M

eV

)

ToF (nsec)

Eplas (ch)

40

9

ZOOM

E – E

E – ToF

Eplas(channel)

57Ni

54Co56Co55Co

52Fe53Fe

54Fe55Fe

51Mn

53Mn52Mn

50Mn

54Mn

49Cr

51Cr50Cr48Cr

52Cr

48V49V

50V47V47Ti46Ti 46V

45Ti44Ti 43Sc43Ca42Ca39K38Ar

41K40K

42K39Ar40Ar

41Ca

36Ar37Ar

40Ca38K 37Cl

44Sc45Sc

ToF(nsec)

ES

i (M

eV

)

E – E

E – ToF

5858Ni+Ni+2727Al @ 40AMeVAl @ 40AMeV

To calculate the transmission and yields of fragments produced and collected in a spectrometer

(*)

(*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002) 661-665

•Ottica magnetica del fragment separator

•Spessore dei vari materiali (degrader, rivelatori, etc.)

•Rigidità magnetica Bρ dello ione scelto

INPUTMatrici di trasporto

•Rese isotopiche

•Matrici ΔE-ToF, ΔE-E

•Spettri E, ΔE, x, y

OUTPUT

Sezioni d’urto:

1. Param. EPAX

2. Valori sperimentali

OPZIONI

E(M

eV

)

ToF(nsec)

4040Ar+Ar+99Be @ 40AMeVBe @ 40AMeV

ΔE-ToFLise

ΔE-ToFexperimenta

l

0.8AMeV

23AMeV

experimental

39Cl23AMeV

Energy(AMeV)

40Ar+9Be 40AMeV

ΔE/E=3%

Lise simulation

1.5AMeV

21.2 AMeV

56Co21.7AMeV

Energy(AMeV)

58Ni+27Al 40AMeVexperimental Lise simulation

ΔE/E=7%

for

20Ne+9Be 45AMeV

∆E

(M

eV)

18Newith 27Al 200μm degrader

SECONDARY REACTIONS

ANGULAR AND ENERGETIC STRAGGLING

Better separation for isotopes with the same A/Z

Riductions of contaminants

(*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002) 661-665

∆E

(M

eV)

No degrader

18Ne

(*)

20Na

19Ne

18Ne

Bρ=1.58 Tm

20Na

19Ne

Bρ=1.57 Tm

20Na19Ne

18Ne17Ne17F

16F15O

14O

Bρ=1.63 Tm20Na

19Ne

18Ne17Ne

15O

Bρ=1.61 Tm

17Ne

15O14O

Bρ=1.64 Tm21Na

20Na20Ne19Ne

18Ne17Ne

18F17F

16F16O15O

14O14N13N

12N12C11C 10C10B 9B

No degr

20

20N

e+

Ne+

99Be @

45

AM

eV

Be @

45

AM

eV

C+Be ioni/sec Ar+Be ioni/sec Ni+Al

ioni/sec

12N 61.2 ± 3 39Cl 237 ± 7 55Co 259 ± 6

10C 29.0 ± 2 36S 95.8 ± 3 53Fe 97 ± 4

8B 8.8 ± 1 34P 43 ± 2 54Fe 54 ± 3

31Si 22 ± 1 53Mn 49 ± 3

Gaussian Fits to obtain the

yields

I = 100 epA

Primary intensity 100 enA (*103)

105 ioni/sec

Ne+Be

ioni/sec

21Na 16.5 ± 4

18Ne 10.8 ± 3

15O 16.2 ± 4

13N 5.3 ± 2

I = 10 enA

Cross-Comparison with LISE

20Ne+9Be 45AMeV

Rate

(io

ni/

sec)

massa

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

7 8 9 10 11 12 13

l i seexp

12C+9Be 62AMeV

1. E+00

1. E+01

1. E+02

1. E+03

1. E+04

1. E+05

1. E+06

9 12 14 16 19 20 21 24 25 26 27 30 31 32 35 37 39

exp

l i se

ClS

PSiAlMg

NaNeFONC

40Ar+9Be 40AMeV

1. E- 02

1. E- 01

1. E+00

1. E+01

1. E+02

1. E+03

1. E+04

20

23

25

27

29

31

33

35

37

38

42

43

44

45

46

50

51

52

53

55

58

exp

lise norm

Ni

Co

FeMnCrV

TiScCaKArClSP

SiAl

Mg

Na

Ne

58Ni+27Al 40AMeV i=3enA

i=7enA

i=100epA

very good transmission efficiency up to 20 degrees cave

feasibility of experiments with such RIBs

Tra

nsm

issio

n %

20Ne+9Be 45AMeV

21Na20Ne19Ne18Ne

Ciclope beam line

20 degrees beam line

OPTICAL TRANSPORT by using pilot beam STABLE BEAM PROPERLY

DEGRADED

Secondary 20Na

1.E- 01

1.E+00

1.E+01

1.E+02

1.E+03

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Mass (A)

Rate

(pph)

Ne

F

O

N

C

B

Be

Li

C - 1000um

Study of FRAGMENTATION CROSS SECTIONS of RIBs

on a Carbon target

208Pb18Ne

18Ne*16O

2He

208Pb18Ne

18Ne*16O

Search for DI-PROTON DECAY of excited states of

18Ne

22Na21Na21Ne

20Ne19Ne

18Ne19F

18F17F

16O 15O15N14N

13C13N

12C11C11B

17O

Secondary Target

(ΔE,ToF) (x,y)

(A,Z), E

Secondary Ion

Si-Strip 1616

Tagged Ion

Si-Strip X-Y Position

measured in the 20° line

89 THREE-FOLD TELESCOPES

ARRAY 4.5°16.5°

81 TWO-FOLD TELESCOPES

ARRAY 4.5°4.5°

EVENT DISPLAY:

Three body event withCarbon Target

EVENT DISPLAY Three body event

withCarbon Target

21Na21Ne20Ne

19Ne18Ne18F

17F16O 15O14N

13C12C 11C11B

21Na selected on all the strips

Extra-production of C and O to be better

investigated!

Cross – Section of products from 21Na + C

Proton rich with 58Ni+27Al and 20Ne+9Be

Neutron rich with 40Ar+9Be

Light proton rich with 12C+9Be

Measured yields are in good agreement with LISE simulation Ions tagging is possible Optimized transmission of the RIBs up to some experimental area Experiments already started

0

5

10

15

20

25

30

0 10 20 30 40N

ZNi+Al

Nuclei stabili

Ar+Be

C+Be

Ne+Be

Eliminazione RF

(Plastico / PPAC)

Sostituzione elementi magnetici (quadrupoli)

Tracciatura eventi

208Pb18Ne

18Ne*16O

208Pb18Ne

18Ne*16O

2He

Sezione d’urto dell’ordine di 100 mbarn (Eccitazione Coulombiana)

Branching ratio di circa 10-3

1818 **

0.01

0.1

1

10

100

1 10 100 1000 10000

Thickness=100

Thickness=200

Thickness=300

Thickness=400

Thickness=500

1 hour

1 min =1 mbarn

=0.5 barn

=1 barn

Primary Beam Current (enA)

Tim

e (

sec)

41Cl (target=5mg/cm2, Production target 500m)

40Cl Induced Reaction for Target Thickness=5mgr/cm2 and =1barn

React

ion P

roduct

s R

ate

(event/

sec)

Primary Beam Current (enA)

Estimated minimum beam intensities for various experiments with fast fragmentation

RIBs@RIA.

Method Part /sec

Physics

Detection and identification

10–5 Limits of nuclei, Existence

Stripping reactions 104 Nuclear properties beyond

the drip lines

Mass measurements

10–2 Masses, explosive nucleosynthesis

Interaction cross section

10–2 Radii, nuclear size

Knockout reactions 105 Halos, cluster models, spectroscopic factors

Heavy-ion collisions

105 Nuclear compressibility,

EOS, supernovae

Giant dipole resonance

106 Nuclear size and shape,

r-process

Nuclear size and shape, r-process

107 Nuclear compressibility,

EOS, neutron stars, supernovae

Coulomb excitation (2+)

1 Evolution of shell structure,

r-process

Elastic scattering 103 Radii, density distributions

Inelastic scattering 103 Nuclear structure,

rp-process

Nuclear structure, rp-process

104 Proton drip line, rp-process

Charge exchange 106 Gamow-Teller strength,

supernova core evolution,

Lifetimes/? -decay studies

10–3 Nuclear deformation, shell

evolution, explosive

Estimated beam intensities for various experiments with fast fragmentation RIBs @ RIA

Spettro YLise

Spettro X-YPPAC

Matrice X-Y Si-Strip

Si-Strip 16X16 Si-Strip 16X16

(300μm)(300μm)

50x50mm50x50mm22

ToF (nsec)

ES

i (M

eV

)

C12+Be9(500um) 62 AMeV settings on 11C NoDegrader

12

9C12+Be9(500um) 62 AMeV Bp=1.8764

E – ToFsperimental

e

E – ToFLISE

FRIBs Test point

Ciclope Test Point

CFD

CFD

CFD

CFD

CFDCFD

Fast. Amp

Lin. Amp

Lin. Amp

X left

X rightY upY down

PPAC

Si

Plastic RFAND

ADCE

E

GATE

TDC

S

T

A

R

T

COMMON

STOP

Spettri in energia del

rivelatore a Si

E (MeV)

Cou

nts

Spettro α

1. La terna di quadrupoli Q1-Q3 focalizza i frammenti nel dipolo D1

2. D1 effettua la prima selezione in Bρ

3. La terna di quadrupoli Q4-Q6 crea il fuoco intermedio

4. Un degrader (opzionale) causare una perdita di energia Z2

5. I quadrupoli Q7-Q9 creano il fuoco finale acromatico, in cui la posizione degli ioni è indipendente dal loro impulso

6. D2 effettua una seconda selezione in p/q.

Degrader

Q1 Q2 Q3

Q4 Q5 Q6

Q7 Q8 Q9

D1

D2

Bersaglio di produzione

selezione A/Z

selezione A/Z

dE/dx Z2

Laboratorio Acceleratore Frag. Sep. Energie(AMeV)

GANIL

RIKEN

GANIL

GSI

NSCL -MSU

LANZHOU

Ciclotroni

Ciclotroni

SIS

Ciclotrone

Ciclotroni

Ciclotrone

SISSI + LISE

A1200

FRS o ESR

RIPS

ACCULINNA&COMBAS

RIBLL

<95

<200

<1200

<150

<100

<80

Laboratorio Accel. Primario Post-acceler. Energie

Ciclotrone

Ciclotroni

PS Booster

Sincrotrone

Ciclotrone

Ciclotrone

Louvain le Neuve

SPIRAL-GANIL

ISOLDE-CERNTRIUMF-Vancouver

ORNL Oak Ridge

ANL- Argogne

Ciclotrone K110

CIME

LINAC

LINAC

TANDEM

ATLAS

0.2-12 AMeV

2-25 AMeV

<2.2 AMeV

1.5-6.5 AMeV

25 MVolt

6-15 AMeV

..extended evalution of fundamental nuclear

properties(massa data e charge radius data

Calcolo di trasmissione e rese di frammenti e residui di fusione prodotti e raccolti da un Fragment Separator

(*)

ToF(nsec)

E(M

eV

)

(*) D.Bazin, M.Lewitowicz, O.Sorlin, O.Tarasov, Nucl.Instr. and Meth. A482(2002) 314O.B.Tarasov, D.Bazin, M.Lewitowicz, O.Sorlin, Nuclear Physics A701(2002) 661-665

•Emittance = 20 p mm mr•Solid Angle = 0.32 msr•Brmax = 18 Tm•Dp / p = 2%•Resolving Power = 1600 at Middle Focus•Achromatic at Final Focus

Primary Beam

from SIS

B – E – BTechnique

•INTENSITA’ ~ 10 ioni/sec

TARGET SECONDARI SPESSI ~ 500mg/cm2

FASCI O 38S 40S 42S 44Ar 46Ar

Energia(AMeV) 39.2 39.5 40.6 33.5 35.2

I ntensità(sec- 1) 5104 1.7104 1.8104 5104 2.7104

Bersaglio(mg/cm2) 184 184 184 93 93

σ(E2;gs 2+) (mb) 59 94 128 81 53

Progetto LNS: EXCYT (1994) (CS+TANDEM)

FRIBs (CS+FRS)

,LNS

Electrods

Electrods

Thickness 300m

The coordinates of each particle are defined in term of the reference particle We need 6 variables to characterize the particle in the phase-space:

(ion-optics convention on phase space)x,y are positions or displacement from the central orbitx’ ,y’ are angles with respect to the central orbit l is the path length difference is the fractional momentum deviation from the assumed central trajectory

ds

x’x

dxx s

Central orbit

xs plane

),,,,,( lyyxxp

VerticalHorizontal

Longitudinal

The charge particle motion can be reduced to a process of matrix multiplication

l

y

y

x

x

X

06661

21

1611

............

..................

..................

..................

...............

............

l

y

y

x

x

RR

R

RR

l

y

y

x

xThe action of a magnet on the particle coordinates is represented by a 66 matrix

The 6 variables are component of a vector

Each magnetic element has its own characteristic matrix TRANSFER MATRIX

The transfer matrix for a succession of magnet is the product of the transfer matrix for individual elements.

)1()2()3(...)()( RRRnRtR

For a static magnetic system with midplane symmetry:

0

565251

4443

3433

262221

161211

100000

100

0000

0000

000

000

l

y

y

x

x

RRR

RR

RR

RRR

RRR

l

y

y

x

x

The motion along x and y can be decomposed NO MIXED TERM

ΔE-ToFexperiment

al

22Na

21Na21Ne20Ne

19Ne18Ne

19F18F

17F16O 15O

15N14N13C

13N12C

11C11B

17O

20

20N

e+

Ne+

99Be @

45

AM

eV

Be @

45

AM

eV

ΔE-ToF ΔE-ToF (experimental)(experimental)

ΔE-ToF ΔE-ToF (LISE)(LISE)

Q7Q4,5,6Q8

Q9D2

Degrader

Q1 Q2 Q3

Q4 Q5 Q6

Q7 Q8 Q9D1

D2

Prod. Target

Fragment Separator

Production Target

Q1,2

27Al (100m)58Ni 40 AMeV

9Be (500m)

40Ar 40 AMeV12C 62 AMeV

20Ne 45 AMeV

Sezioni d’urto di frammentazione di 129Xe in un bersaglio di 27Al a 800AMeV. Linea tratteggiata EPAX 1, linea continua EPAX 2.

INDIPENDENTE DALL’ENERGIA nel centro di massa (“limiting fragmentation”)

NON DESCRIVE la frammentazione di PROIETTILI FISSILI e reazioni di PICK-UP

per frammenti con A~Ap DISTRIBUZIONE ISOTOPICA centrata su N/Z del proiettile e con varianza Δ piccola.

Fragments far away from the projectile (ΔA>15-20%) DISTRIBUZIONE ISOTOPICA INDIPENDENTE DAL PROIETTILE, posizione, forma ed ampiezza dipendenti solo da Af (statisical evaporation from an excited pre-fragment)

PARAMETRIZZAZIONE delle sezioni d’urto di frammentazione

CARATTERISTICHE

))(exp()(),(U

ffpfff ZAZRnAYZA

))((exp)()( fAPApAPpAPSfAY

)( 13/13/1

2 SAASS pp

12ln PAPP p

Total cross section of elements with mass Af

it accounts for the peripheral nature of the reaction

Pendenza della resa in massa

probprob ZZ Carica più probabile

CHARGE DISPERSION

ISOBARIC CROSS SECTION

**

(*) K. Summerer et al. Phys. Rev. C42, 2546 (1990) Phys. Rev. C52, 1106 (1995)