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George A. Souliotis Collaborators: M. Veselsky, G. Chubarian, L. Trache, A. Keksis,

a) Neutron-Rich Rare Isotope Production in the Fermi Energy Domain (Slides:1-12) b) Heavy Residue Properties, Isoscaling and N/Z Equilibration (Slides: 13-29). George A. Souliotis Collaborators: M. Veselsky, G. Chubarian, L. Trache, A. Keksis,

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George A. Souliotis Collaborators: M. Veselsky, G. Chubarian, L. Trache, A. Keksis,

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  1. a) Neutron-Rich Rare Isotope Production in the Fermi Energy Domain (Slides:1-12) 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:deepinelastic 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 D2 D1 Production Target Wien Filter Q3 Q2 Q1 Final Achromatic Image D3 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 Kr+Ni (gr = 3.5o) 4o (2.5-5.5o) for Kr+Sn (gr = 6.5o) Silicon Telescope: ΔE1, X,Y (Strips) ΔE2, 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: ΔE1, ΔΕ2, Εr , (x,y) strips  time of flight (START-STOP)  x-position at First Image (Bρ information) Extracted physical quantities:  Velocity, Energy loss, Total Energy  Mass-to-charge ratio: A/Q B ~ A/Q  Atomic Number ZZ ~  ΔE1/2 Ionic charge Q Q ~ f(E, ) Mass number A A = Qint  A/Q Yield distribution (Z,A,υ)

  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 (θ, Bρ) Isobaric Yield Distribution • -- DIT/GEMINI • - DIT/GEMINI • filtered (θ,Bρ) • -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, Α spectra (one run): 86Kr(25 MeV/u) + 64Ni Resolutions (FWHM) : ΔZ = 0.5 ΔQ = 0.4 ΔA = 0.5

  8. Mass distribution of Ge (Z=32) isotopes 86Kr(25 MeV/u) + 64Ni - 4p - 4p+1n - 4p+2n

  9. Mass distributions: 86Kr (25 MeV/u) + 64Ni*  Data ---- EPAX DIT/GEMINI • 1p • +1n • +2n • +3n • +4n • 2p • +1n • +2n • +3n • +4n Br Se Larger cross sections w.r.t. DIT/GEMINI or EPAX (Z=35-31) • 3p • +1n • +2n • +3n • 4p • +1n • +2n Ge As Cross sections similar to DIT/GEMINI or EPAX (Z  30) Ga Zn • 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: 86Kr+64Ni 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 Br Se Larger cross sections with the n-rich 124Sn target (Z=35-30) Ge As • 3p • 4p Ga Zn • 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 : •86Kr+124Sn,112Sn R21 (N,Z)= Y2/Y1 R21 = C exp (  N ) R21 = C´ exp (  Z )

  21. Scaling of Yield Ratios : •86Kr+64Ni,58Ni R21 (N,Z)= Y2/Y1 R21 = C exp (  N ) R21 = C´ exp (  Z )

  22. Isoscaling Parameters: ,  • 86Kr+124Sn,112Sn • 86Kr+64Ni,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) exp{B(N,Z)/T} exp { (Nn+Z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 86Kr+124Sn => [210Rn] 1.44 86Kr+112Sn => [198Rn] 1.30  = 4 Csym/T ( (Z1/A1)2– (Z2/A2)2) *  = 8 Csym/T (Z/A)3ave (N/Z) • 86Kr+124Sn,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 ) 86Kr+124Sn,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 86Kr+124Sn => [210Rn] 1.44 86Kr+112Sn => [198Rn] 1.30  = 4Csym/T (Z/A)2ave (N/Z)qp ** 86Kr+124Sn,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 A&M: 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

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