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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)