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Coulomb excitation and b -decay studies at (REX-)ISOLDE around Z = 28

Coulomb excitation and b -decay studies at (REX-)ISOLDE around Z = 28. J. Van de Walle – KVI - Groningen. 1. ISOLDE and REX-ISOLDE ; 2. Results around Z=28 : Odd-A cupper isotopes (Z=29) ; Even-A zinc isotopes (Z=30) ; Even-A iron isotopes (Z=26 ) ;. ISOLDE and REX-ISOLDE.

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Coulomb excitation and b -decay studies at (REX-)ISOLDE around Z = 28

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  1. Coulomb excitation and b-decay studies at (REX-)ISOLDE around Z = 28 J. Van de Walle – KVI - Groningen • 1. ISOLDE and REX-ISOLDE ; • 2. Results around Z=28 : • Odd-A cupper isotopes (Z=29) ; • Even-A zinc isotopes (Z=30) ; • Even-A iron isotopes (Z=26) ;

  2. ISOLDE and REX-ISOLDE - Resonance Ionization Laser Ion Source  brings in unique beams ! - 30 - 60 keV beams (low energy) - Around 600 isotopes of 60 elements available - b-decay studies REX-ISOLDE (high energy) : low energy Coulomb excitation < 3 MeV/u using the MINIBALL germanium array.

  3. ISOLDE and REX-ISOLDE • ISOTOPE Yields around Z = 28 : • Zn, Cu, Ni, Mn RILIS ; • UCx target – fission by 1.4 GeV protons – 2 mA ; • 30 keV beams ; • b-decay of 61-68Mn Zn (Z=30) Yield / mC Cu (Z=29) Ni (Z=28) Mn (Z=25) b-decay studies Mass

  4. ISOLDE and REX-ISOLDE • ISOTOPE Yields including REX efficiency : • Zn, Cu, Ni, Mn post-acceleration possible ; • 61,62,63Mn/Fe, 68Ni, 67,69,71,73Cu and 74,76,78,80Zn. Zn (Z=30) Yield / mC Cu (Z=29) Ni (Z=28) Mn (Z=25) Mass

  5. Results around Z=28 : introduction • Specific nuclear structure questions : • Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin •  motivated by the "tensor part" of the strong interaction • Collectivity sets in around major shell gaps ; • Evolution of single particle energies ; 50 50  g9/2 g9/2  40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  Tensor part pj>/< - nj’</> = attractive (pf5/2-ng9/2 , pp1/2-ng9/2 ) pj>/< - nj’>/< = repulsive (pf7/2-ng9/2 , pp3/2-ng9/2 ) p3/2 llll p3/2  28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p

  6. Results around Z=28 : introduction • Specific nuclear structure questions : • Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin •  motivated by the "tensor part" of the strong interaction • Collectivity sets in around major shell gaps ; • Evolution of single particle energies ; Zn Ni Energy [MeV] 50 50  g9/2 g9/2  40 40 Fe 0+ p1/2 p1/2  ll f5/2 f5/2 llllll  p3/2 llll p3/2  28 28 4+ llllllll llllllll f7/2 f7/2 2+ sd-shell sd-shell n p Neutron Number

  7. Results around Z=28 : introduction • Specific nuclear structure questions : • Evolution of Z=28, N=40 and N=50 shell gaps at extreme isospin •  motivated by the "tensor part" of the strong interaction • Collectivity sets in around major shell gaps ; • Evolution of single particle energies ; Zn Ni Energy [MeV] 50 50  g9/2 g9/2  40 40 Fe 0+ p1/2 p1/2  ll f5/2 f5/2 llllll  p3/2 llll p3/2  28 28 4+ llllllll llllllll f7/2 f7/2 2+ sd-shell sd-shell n p Neutron Number

  8. Results around Z=28 : Odd-A cupper isotopes • Odd-A cupper isotopes (Z=29) b-decay of neutron-rich Ni isotopes at LISOL facility (gas-cel) 50 50   g9/2 g9/2 40 40 p1/2 p1/2  ll llllll f5/2 f5/2  l llll p3/2 p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p

  9. Results around Z=28 : Odd-A cupper isotopes • Odd-A cupper isotopes (Z=29) • Spectroscopic factors needed ! • Shell model starts to reproduces this result • 56Ni not a closed core (65% [1], 50% [2] closed core) • [1] Honma PRC69 034335 (2004), [2] Otsuka PRL 81 1588 (1998) Coulomb excitation of neutron-rich Cu isotopes at REX-ISOLDE facility ("RILIS") 50 50   g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  l p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p

  10. Results around Z=28 : Even-A zinc isotopes Even-A zinc isotopes (Z=30) • onset of collectivity around N=40 ?E(2+1) !!! • neutron pair scattering at N=40 ? E(0+2) !!! • Influence of proton excitations across Z=28 ? • Influence of neutron excitations across N=50 ? 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  ll p3/2 llll p3/2 28 28 Neutron number llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p

  11. Results around Z=28 : Even-A zinc isotopes Even-A zinc isotopes (Z=30) • onset of collectivity around N=40 ?E(2+1) !!! • neutron pair scattering at N=40 ? E(0+2) !!! • Influence of proton excitations across Z=28 ? • Influence of neutron excitations across N=50 ? 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  ll p3/2 llll p3/2 28 28 Neutron number llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p

  12. Results around Z=28 : Even-A zinc isotopes N = 50 isotones 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 llll f5/2 llllll llll p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p Z

  13. Results around Z=28 : Even-A zinc isotopes N = 50 isotones • Early Ji-Wildenthal • empirical effective interaction PRC 37, p. 1256 (1988) 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 llll f5/2 llllll llll p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p Z

  14. Results around Z=28 : Even-A zinc isotopes The benefit of post-accelerated RIBs ! N = 50 isotones ORNL - Padilla-Rodal et al., PRL 94, 122501 (2005) 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  llll p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p Z

  15. Results around Z=28 : Even-A zinc isotopes The benefit of post-accelerated RIBs ! N = 50 isotones REX-ISOLDE - Van de Walle et al., PRL 99, 142501 (2007) 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  ll p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p Z

  16. Results around Z=28 : Even-A zinc isotopes N = 50 isotones • Early Ji-Wildenthal • empirical effective interaction PRC 37, p. 1256 (1988) • G-matrix [M. Hjorth-Jensen] + monopole adjustments • ep,en = 1.9,0.9 • [N. Smirnova et al] • JJ4B • ep,en = 1.76,0.97 • [A. Lisetskiy, A. Brown, et al] 50 50 llllllllll  g9/2 g9/2 40 40 p1/2 p1/2  ll f5/2 f5/2 llllll  ll p3/2 llll p3/2 28 28 llllllll llllllll f7/2 f7/2 sd-shell sd-shell n p Z

  17. Results around Z=28 : Even-A iron isotopes Even–A iron isotopes (Z=26) t2+ Ljungvalet al., PRC 81, 061301(R) (2010) + Rotheret al.,arXiv:1006.5297 v1 [nucl-ex] . Neutron Number

  18. Results around Z=28 : Even-A iron isotopes Even–A iron isotopes (Z=26) t2+ Ljungvalet al., PRC 81, 061301(R) (2010) + Rotheret al.,arXiv:1006.5297 v1 [nucl-ex] . • Lenziet al., "The land of deformation south of 68Ni" • arXiv:1009.1846v1 [nucl-th] • Include pf7/2, nd5/2orbitals in the valence space • Z=28 shell gap determined from 80Zn B(E2), ep=0.5e Neutron Number

  19. Results around Z=28 : Even-A iron isotopes Even–A iron isotopes (Z=26) t2+ Ljungvalet al., PRC 81, 061301(R) (2010) + Rotheret al.,arXiv:1006.5297 v1 [nucl-ex] • Lenziet al., "The land of deformation south of 68Ni" • arXiv:1009.1846v1 [nucl-th] • Include pf7/2, nd5/2orbitals in the valence space • Z=28 shell gap determined from 80Zn B(E2), ep=0.5e Low energy Coulex : s(B(E2),Q(2+)) Neutron Number

  20. Results around Z=28 : Even-A iron isotopes b-decay 4+ 62Mn 2+ 0+ 62Fe COULEX 62Mn 62Mn + 62Fe

  21. Results around Z=28 : Even-A iron isotopes Counts / 4 keV Energy [keV] 419 keV (3,4)+ 4+ 62Mn 877 keV 2+ 0+ 62Fe COULEX Gaudefroyet al., EPJA 23, 41-48 (2005)

  22. Results around Z=28 : Even-A iron isotopes 419 keV (3,4)+ 4+ 62Mn 877 keV 2+ 0+ 62Fe COULEX preliminary

  23. Results around Z=28 : Even-A iron isotopes 0+ (*) Preliminary half lives 62Cr (1+) x b-decay (3+,4+) 0.77(5) ms (*) 4+ 62Mn Ni 0+ 2+ 4+ Energy [MeV] 62Fe 2+ Fe 0+ 4+ 2+ Neutron Number

  24. Results around Z=28 : Even-A iron isotopes 0+ (*) Preliminary half lives 62Cr (1+) x 0.15(1) ms (*) b-decay (3+,4+) 0.77(5) ms (*) 4+ 62Mn 0+ Ni 0+ 2+ 4+ Energy [MeV] 62Fe 2+ Fe 0+ 814 keV: 152(13) ms 4+ 2+ Neutron Number

  25. ... thanks !

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