1
a) Neutron-Rich Rare Isotope Production in
the Fermi Energy Domain (Slides1-12)
b) Heavy Residue Properties, Isoscaling and
N/Z Equilibration (Slides 13-29)
 George A. Souliotis Collaborators M.
Veselsky, G. Chubarian, L. Trache, A. Keksis,
E. Martin, D.V. Shetty, S.J. Yennello Recent
research results presented at I
The International Conference of
Nucleon-Nucleon Collisions (NN03),
Moscow, June 17-22, 2003, and
The Institute of Nuclear Physics of
NCSR Demokritos, Athens,
Greece, June 24, 2003
2
Introduction
   Production of
Neutron-Rich Nuclides (methods) ? target,
projectile fission   ?  cold projectile
fragmentation (medium to high energy)  
? deep inelastic collisions (low to medium
energies) ?  multinucleon transfer reactions
(around Vb)    Present work deep inelastic
collisions at Fermi energies
?  86Kr(25MeV/nucleon) 64Ni, ( PLB 543
163 (2002) ?  86Kr
124Sn, 112Sn (PRL in press , nucl-ex 0302011)
?  Heavy-Residue Yield
Scaling (nucl-ex 0305027) Findings ? Enhanced
production of neutron-rich species, neutron skin
effect ? Heavy-Residue Yield
Ratios probing N/Z equilibration

Applications with RIB from TAMU upgrade and RIA

3
MARS Recoil Separator and Setup
Dispersive Image
D1
D2
Production Target
Wien Filter
Q3
Q2
Q1
D3
Final Achromatic Image
PPAC1 Start T X,Y
Q4
Q5
Rotatable Arm Reaction Angle 0-12o (selectable)
PPAC2 Stop T
Beam angle set to 0o (1.0-3.0o) for KrNi
(?gr 3.5o) 4o (2.5-5.5o) for KrSn (?gr
6.5o)
Silicon Telescope ?E1, X,Y (Strips) ?E2,
Eresidual
MARS Acceptances Anglular 9 msr Momentum 4

4
Experimental Details
Reactions studied ? 86Kr 22 (25 MeV/u,
1-5 pnA) 64Ni (4 mg/cm2) PLFs in
1.0-3.0o (?gr 3.5o)
? 86Kr 22 (25 MeV/u, 1-5 pnA)
124,112Sn (2 mg/cm2) PLFs in 2.5-5.5o (?gr
6.5o) Measured quantities ? ?E1, ??2, ?r
, (x,y) strips ? time of flight
(START-STOP) ? x-position at First Image
(B? information)
Extracted physical quantities ? Velocity,
Energy loss, Total Energy ? Mass-to-charge
ratio A/Q B? A/Q ? ?
? Atomic Number Z
Z ? ?E1/2 ? Ionic charge Q
Q f(E, ?)
? Mass number A
A Qint ? A/Q   Yield
distribution (Z,A,?)  
5
Gross Distributions 86Kr (25 MeV/u) 64Ni
Isobaric Yield Distribution

•  
• ----- DIT/GEMINI
• - - DIT/GEMINI
• (filtered)

Z - A Distribution (relatice to Z?)
Velocity - A Distribution
References
DIT L. Tassan-Got and C. Stephan, Nucl.
Phys. A524 121 (1991) GEMINI R. Chariy et al.,
Nucl. Phys. A483 391 (1988) EPAX K.
Summerer and B. Blank, Phys. Rev. C61 034607
(2000).
6
Gross Distributions 86Kr (25 MeV/u) 124Sn
? Data ? Data Corrected (?, B?)
Isobaric Yield Distribution

• -- DIT/GEMINI
• - DIT/GEMINI
• filtered (?,B?)
• - EPAX2

Z - A Distribution (relatice to Z?)
Velocity - A Distribution
References
DIT L. Tassan-Got and C. Stephan, Nucl.
Phys. A524 121 (1991) GEMINI R. Chariy et al.,
Nucl. Phys. A483 391 (1988) EPAX2 K. Summerer
and B. Blank, Phys. Rev. C61 034607 (2000).
7
Z, Q, ? spectra (one run) 86Kr (25 MeV/u)
64Ni
Resolutions (FWHM) ?Z 0.5
?Q 0.4
?A 0.5
8
Mass distribution of Ge (Z32) isotopes

86Kr (25 MeV/u) 64Ni
- 4p
- 4p1n
- 4p2n
9
Mass distributions 86Kr (25 MeV/u) 64Ni
? Data ---- EPAX ? DIT/GEMINI

• 2p
• 1n
• 2n
• 3n
• 4n

• 1p
• 1n
• 2n
• 3n
• 4n

Br
Se
Larger cross sections w.r.t. DIT/GEMINI or
EPAX (Z35-31)

• 3p
• 1n
• 2n
• 3n

• 4p
• 1n
• 2n

Ge
As
Cross sections similar to DIT/GEMINI or EPAX (Z
? 30)
Zn
Ga

• 5p
• 1n

• 6p

G.A. Souliotis et al., Phys. Lett. B 543, 163
(2002)
10
Mass distributions (cont.) 86Kr (25 MeV/u)
64Ni

• Data
• ---- EPAX
• ? DIT/GEMINI

Ni
Cu
Measured cross sections are similar to
DIT/GEMINIand EPAX
Fe
Co
Cr
Mn
11
Mass distributions 124Sn (20 MeV/u) 124Sn

• Data
• ---- EPAX
• ? DIT/GEMINI

?
Ni
Cu
Measured cross sections agree with
DIT/GEMINI They are 10-100 larger than EPAX
predictions
Fe
Co
Cr
Mn
12
Estimates of Production Rates 86Kr64Ni
Use cross sections of this work, assume
86Kr beam (25MeV/u) 100 pnA
64Ni target (20 mg/cm2)
 

GSI data M. Weber et al . Nucl. Phys. A
578 (1994) 659
13
Mass distributions 86Kr (25 MeV/u) 124Sn,
112Sn
? 86Kr 124Sn ? 86Kr 112Sn ----- EPAX

• 1p

• 2p

Se
Br
Larger cross sections with the n-rich 124Sn
target (Z35-30)
Ge
As

• 3p

• 4p

Zn
Ga

• 5p

G.A. Souliotis et al., Phys. Rev. Lett.
in press, nucl-ex/0302011
14
Neutron-Proton Density Calculations for 124Sn,
112Sn
n
neutron skin
p
n
p
Thomas-Fermi
V.M. Kolomietz, A.I. Sanzhur et al., PRC 64,
024315 (2001) ------- Skyrme-Hartree-Fock
J. Friedrich, P. Reinhard, PRC 33, 335 (1986)
15
Mass Distribution of Germanium from
86Kr(25MeV/u) 124Sn,112Sn, 64Ni
Data using targets ? 124Sn ? 112Sn ?
64Ni ------ EPAX2
Ge
Target N/Z
Valley of stability 124Sn 1.48
n-rich 118Sn
112Sn 1.24
n-poor 64Ni 1.29
n-rich 60Ni
16
Comparison Data, Calculations 86Kr (25
MeV/u) 124Sn, 112Sn
? Data DIT/GEMINI (standard)
DIT/GEMINI with ?(r) EPAX
Calculation with neutron skin appears to
account for the larger cross sections with the
n-rich 64Ni, 124Sn targets
G.A. Souliotis et al., Phys. Rev. Lett.
in press, nucl-ex/0302011
17
Comparison Data/EPAX 86Kr (25 MeV/u)
64Ni, 124Sn
For near-projectile fragments and above the
projectile N/Z, the cross sections are
larger. DIC between massive n-rich nuclei appear
to be advantageous for very high N/Z RIB
production
18
Velocity vs Z correlation
86Kr 124Sn 86Kr 112Sn
?min E/A 2.2 MeV T 5.3 MeV
86Kr 64Ni 86Kr 58Ni
?min
19
N/Z vs Z correlation
86Kr 124Sn 86Kr 112Sn
N/Z
86Kr 1.39 124Sn 1.44 112Sn 1.24
SL stability line
N/Z constant
EAL evaporation attractor line
86Kr 64Ni 86Kr 58Ni
64Ni 1.29 58Ni 1.07
R. Charity, Phys. Rev. C 58, 1073 (1998)
20
Scaling of Yield Ratios
86Kr124Sn,112Sn
R21 (N,Z) Y2/Y1
R21 C exp ( ? N )
R21 C exp ( ? Z )
21
Scaling of Yield Ratios
86Kr64Ni,58Ni
R21 (N,Z) Y2/Y1
R21 C exp ( ? N )
R21 C exp ( ? Z )
22
Isoscaling Parameters ?, ?
86Kr124Sn,112Sn
86Kr64Ni,58Ni
? 0.43 ? 0.27
R21 C exp ( ? N )
R21 C exp ( ? Z )
? 0.34 ? 0.51
23
Origin of Isotopic Scaling
Grand Canonical Ensemble (equilibrium limit)
Fragment Yield Y(N,Z) F(N,Z)
expB(N,Z)/T exp (N?nZ?p)/T R21 (N,Z)
Y2(N,Z) / Y1(N,Z) C exp ( ? N ? Z)
(Isoscaling) with ? ??n/T ?
??p/T ??n ? ??Sn


??p ? ??Sp
? 4 Csym/T ( (Z1/A1)2 (Z2/A2)2 )
Extracted Parameters
J. Randrup and S. Koonin, Nucl. Phys. A 356,
223 (1981) M. B. Tsang et al. Phys. Rev. C
64, 054615 (2001) A.S. Botvina et al. Phys.
Rev. C 65, 044610 (2002)
24
Heavy Residue Isoscaling and N/Z equilibration
R21 exp ( ? N )

N/Z 86Kr124Sn gt 210Rn 1.44 86Kr112Sn gt
198Rn 1.30
? 4 Csym/T ( (Z1/A1)2 (Z2/A2)2 )
? 8 Csym/T (Z/A)3ave ?(N/Z)
86Kr124Sn,112Sn
?(N/Z) 0.14 N/Z equilibrated quasi-projectile
Evolution towards N/Z equilibration of
quasi-projectile
M. B. Tsang et al. Phys. Rev. C 64, 054615
(2001) A.S. Botvina et al. Phys. Rev. C 65,
044610 (2002)
G.A. Souliotis et al., nucl-ex/0305004, Phys.
Rev. C submitted
25
Velocity and E vs mass correlations
86Kr 124Sn 86Kr 112Sn
?min E/A 2.2 MeV T 5.3 MeV
E/A max observed
26
Isobaric Scaling of Yield Ratios
R21(N,Z) Y2/Y1
R21 C exp ( ? N ? Z) Rearrange with
? (? ?)/2
? (?
-?)/2 R21 C exp ?A ?(N? Z) C exp (?A
2?tz )
86Kr124Sn,112Sn data
?0.47
? 0.47
?
A.S. Botvina et al. Phys. Rev. C 65, 044610
(2002)
27
Heavy Residue Isobaric Scaling and N/Z
equilibration
R21 exp ?? (N?Z)

N/Z 86Kr124Sn gt 210Rn 1.44 86Kr112Sn gt
198Rn 1.30
?? 4Csym/T (Z/A)2ave ?(N/Z)qp
86Kr124Sn,112Sn ? Isobaric approach ? Isotopic
approach
?(N/Z) 0.14 N/Z equilibrated quasi-projectile
Evolution towards N/Z equilibration of
quasi-projectile
N/Z equilibration continuous process strongly
correlated with E
G.A. Souliotis et al., nucl-ex/0305027, Phys.
Lett. B, submitted
Intermediate Energy S.J. Yennello et al,
Phys. Lett. B 321, 15 (1994) (IMF yield ratios)
B.A. Lee and S.J. Yennello, Phys. Rev.
C 52, 1746 (1995)
H. Johnston et al., Phys. Lett. B 371,
186 (1996)
28
Early N/Z equilibration studies
92Mo(15MeV/u) 238U, 154Sm (1)
Derived from data using evap. code
N/Z
Evolution towards N/Z equilibration
58Ni,64Ni (8.5MeV/u) 238U (2)
N/Z equilibrated quasi-projectiles
N/Z
DIC Model (Randrup)
58Ni measured
derived 64Ni measured
derived
(1) M. Petrovici et al. , Nucl. Phys. A 477,
277 (1988) (2) R. Planeta et al., Phys. Rev. C
38, 195 (1988)
29
Summary and Outlook
Measured charge, mass, velocity distributions of
residues from 86Kr (25 MeV/u) 64Ni, 124Sn,
112Sn, Studies inside ?gr Reaction simulations
DIT/Gemini reasonable description,

Effect of the Neutron Skin
(very n-rich products) Scaling of Heavy-Residue
Yields N/Z Equilibration Plans for future work
? Investigate reactions with heavier
targets 208Pb, 238U (look ?gr ) ? Study
the process of N/Z equilibration, E/A dependence
Tools at Texas AM ? Superconducting
Solenoid Rare Isotope Line (Large Acceptance)
? MARS Line (High Resolution) ? Future
Re-accelerated beams via a Gas-Cell based ISOL
concept
Application in studies using high-N/Z beams from
RIA
TAMU Cyclotron
White Paper in http//cyclotron.tamu.edu