fragment isospin as a probe of heavy-ion collisions
DESCRIPTION
Fragment Isospin as a Probe of Heavy-Ion Collisions. Symmetry term of EOS Equilibration “Fractionation” – inhomogeneous distribution of isospin Source composition Energy spectra Dynamics : preequilibrium emission / PLF composition Statistical breakup: composition of fragments - PowerPoint PPT PresentationTRANSCRIPT
Fragment Isospin as a Probe of Heavy-Ion
Collisions• Symmetry term of EOS• Equilibration• “Fractionation” – inhomogeneous distribution of
isospin • Source composition• Energy spectra• Dynamics : preequilibrium emission / PLF composition • Statistical breakup: composition of fragments • recent work at TAMU and IU
– Peripheral / mid peripheral events: PLF and MR
Z
N
Johnston,1995
RuZr
RuZr
z ZZ
ZZZR
detdet
detdetdet )(2
Rami, 2000
projectile neutrons
projectile protons
target neutrons
target protons
B.A. Li, 1996
Isospin Equilibration
Martin poster
Isotopic composition of fragments as a signature of parent system
R. Wada, Phys. Rev. Lett. 58, 1829-1832 (1987)
Fe+FeFe+Ni
Ni+FeNi+Ni
Ramakrishnan et al, PRC 57, 1803 (1998)
30MeV/nucleon 58Fe,58Ni + 58Fe, 58NiCarbon fragments
Dempsey et al, PRC 54, 1710(1996)
124,136Xe + 112,124Sn55MeV/nucleon
Ramakrishnan et al, PRC 57, 1803 (1998)
58Fe, 58Ni + 58Fe, 58Ni 30 MeV/nucleon
.
2
42643
643
HeHeHe
HeHeHe
Z
N
Martin, et al PRC (2000)
Projectile fragmentation (with isotopically reconstructed QP)
• Isospin effects the dynamics
• QP with a diversity in isospin
• Possible route to neutron-rich RNB – > G.Souliotis clip
28Si + 112Sn, 124Sn @ 30,50MeV/nucleon
20F,20Ne, 20Na + Au @ 32 MeV/nucleon
45.3 cm
Ring 5 Ring 4Ring 3
Ring 2Ring 1
82.2°
42.5°33° 57°
33.6° 22.6°22.37°
14.28° 14.10°8.84° 8.71°
4.6° 4.5°1.64°
Cs I(T l)
S i (53 m m ) + S i-S tr ip (1 47 m m ) + S i (994 m m )Te le sco pe (5cm x 5 cm )
S i (135 m ) + S i (9 93 m ) + C sI(T l)Te le sco pe (5cm x 5 cm )
S id e v iew o f th e d e te c to r se tu p .
FAUST
FAUST
Keksis poster
Beam <N/Z>
proj
<N/Z>
DIT
<N/Z>
DIT+evap
<N/Z>
exp
20Na .818 .926 .876 .912
20Ne 1 1.06 .953 1
20F 1.22 1.23 1.02 1.07
Neutron richness
Rowland PLF
20F,20Ne, 20Na + Au @ 32 MeV/nucleon
D. Rowland
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.8 0.9 1 1.1 1.2 1.3
(N/Z)proj
t/3H
e
20Na
20F
20Ne
20F+Ag
20F+Au
20Ne+Au
20Na+Au
Distillation of a neutron-rich gas?Projectile fragmentation of 20Na,20Ne,20F at 35 Mev/nucleon
124Sn 124Sn
Veselsky, Phys. Rev. C 62, 064613 (2000).
0.6 0.8 1.0 1.2
0
1
2
3
4
5
6
7
8
9
IMF
LCP
ch particles
(50 MeV/nuc)
Mu
lt
N/Z
0.6 0.8 1.0 1.2
0
1
2
3
4
5
6
7
8
9
IMF
LCP
ch particles
(30 MeV/nuc)
Mu
lt
N/Z
0.50 0.75 1.00 1.25 1.50
0.5
1.0
1.5
2.0
2.5
3.0
N/ZQP
(N/Z)IMF
/(N/Z)LCP
50 Mev/nucl
(N/Z
) IMF/(
N/Z
) LC
P
(N/Z)QP
Both the multiplicity and neutron content of the fragmentation products are dependent on the N/Z of the fragmenting system
Veselsky, Phys. Rev. C 62, 041605 (2000)
28Si + 112Sn; 30 & 50 Mev/nuc projectile fragmentation reactions
PLF : Z=12-15 => second source
Laforest, PRC 59, 2567 (1999)
50 Mev/nuc
PPAC2 Stop T Silicon Telescope:ΔE1, X,Y (Strips)ΔE2, Er
PPAC1 Start T X,Y
Production Target
D1D2
D3
WienFilter
Q1Q2Q3
Q4Q5
Dispersive Image
FinalAchromatic Image
Rotatable ArmReaction Angle: 0-12o (selectable)
MARS Acceptances:Anglular: 9 msrMomentum: 4 %
Rare Isotope Production with MARS
Souliotis Clip
Fragments at mid rapidity
larger fragments from midrapidity(Rapidity Dist. for Z = 2, 3, 4 for different Multiplicity
Bins)
124Xe, 124Sn + 112,124Sn
Toke, PRL 75, 2920 ( 1995)
28MeV/A 209Bi + 136Xe<b> = 12.4 fm
Shetty poster
Rapidity Dist. for 3He,4He,6He for different Multiplicity Bins
Shetty poster
124Xe, 124Sn + 112,124Sn
Elab/A
3He, 4He, 6He Spectra Comparison124Xe, 124Sn + 112,124Sn
Beam
LASSA: 9 telescope Si(IP)-Si(IP)-CsI(Tl)/PD array; 7lab58
114,106 Cd + 92,98 Mo at E/A = 50 MeV
Si-CsI(Tl)/PD; 2.5lab4.5
Miniball/Wall; Fast
plastic/CsI(Tl); 2lab170
LASSA
Reproducing Ramakrishnan
(neutron deficient isotopes dominate at central angles)
Hudan Clip
Perpendicular velocity spectra
Hudan Clip
Fractional yield as function of perpendicular velocity
Hudan Clip
Elab/A
Spectral Comparison for Z = 3 Isotopes(change in slope trend for heaviest
isotope?)124Xe, 124Sn + 112,124Sn
Shetty poster
isotopic energy spectra (preequilibrium effects)
E. Renshaw, Phys. Rev. C 44, 2618-2624 (1991) J. Brzychczyk, Phys. Rev. C 47, 1553-1562 (1993)
Energy Spectra As a Probe Of Symmetry Potential
B.A. Li, PRL 78, 1544 (1997)
Isotope ratios as function of centrality
H. Xu Phys. Rev. C 65, 061602 (2002)
124,136Xe + 112,124Sn 55MeV/nucleon
Dempsey et al, PRC 54, 1710(1996)
114Cd + 98Mo; 50MeV/nuc
Enhanced neutron richness in central versus peripheral collisions
H. Xu Phys. Rev. C 65, 061602 (2002)
In the spirit of the Gordon Conf…
20F,20Ne, 20Na + Au 32 MeV/nucleon
-0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6-2
0
2
p
d
t
3He
4He
6He
6Li
7Li
8Li
7Be
9Be10Be
10B11B
12B
11C12C13C14C
13N14N15N16N
p
dt
3He
4He
6He
6Li7Li
8Li
7Be
9Be10Be
10B11B12B
11C12C13C14C
13N14N15N16N
p
d
t
3He
4He
6He
6Li
7Li8Li
7Be
9Be
10Be
10B
11B
12B
11C12C13C
14C 13N14N15N
16N
-0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6-8
-6
-4
-2
0
2
4
6
8
m=15.21921b=-2.0641
20F + 197Au
(E
/A)
-0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
m=13.56903b=-1.78458
20F + natAg
(Z/A)
m=1.59837b=-0.32586
(E
/A) 20
F+19
7 Au -
(E
/A) 20
F+na
t Ag (
MeV
)
(Z/A)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.5 1 1.5 2
N/Z
no
rma
lize
d t
ime
Na time
Ne time
F time
all isotopes
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
N/Z
rela
tive
tim
e
R
Summary• Fragment Isospin can tell us about
– Equilibration– Source composition – distribution of isospin
• DIT mechanism can be used to create systems with a diversity of isospin
• Isotopic energy spectra are important to understanding the sources of these fragments
The following people were responsible for bringing you the unpublished data shown
in this presentation…*
• B. Davin, R. Alfaro, H. Xu, L. Beaulieu, Y. Larochelle, T. Lefort, R. Yanez, S. Hudan, A. L. Caraley, R. T. de Souza, T. X. Liu, X. D. Liu, W. G. Lynch, R. Shomin, W. P. Tan, M. B. Tsang, A. Vander Molen, A. Wagner,i H. F. Xi, C. K. Gelbke, R. J. Charity, L. G. Sobotka, A.S. Botvina, D. Rowland, D. Shetty, M. Veselsky, G. Souliotis, E. Martin, A. Keksis, E. Winchester,A. Ruangma G. Charbarian, L. Trache, K. Hagel, T. Keutgen, M. Murray, J.B. Natowitz, L. Qin, R. Wada, M. Cinausero, D. Fabris, E. Fioretto, M. Lunardon, G. Nebbia, G. Prete, V. Rizzi, G. Viesti, J. Cibor, Z. Majka, R. Alfarro, A. Martinez-Davalos, A. Menchaca-Rocha
• DOE, NSF, Welch Foundation
*However they should not be held accountable for the actual presentation