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New Results from MINIBALL

New Results from MINIBALL. R. Krücken Physik Department E12 Technische Universität München & Maier-Leibnitz Laboratory for Nuclear and Particle Physics. New Results from MINIBALL. MINIBALL Low energy Coulomb excitation at REX-ISOLDE Relativistic single nucleon knock-out at the GSI-FRS.

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New Results from MINIBALL

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  1. New Results from MINIBALL R. Krücken Physik Department E12 Technische Universität München & Maier-Leibnitz Laboratory for Nuclear and Particle Physics

  2. New Results from MINIBALL MINIBALL Low energy Coulomb excitation at REX-ISOLDE Relativistic single nucleon knock-out at the GSI-FRS

  3. MINIBALL • - 8 clusters à 3 6-fold segmented crystals • total MINIBALL efficiency ~8% at 1.3 MeV • digital electronics, on-board online pulse shape analysis (PSA) for better position resolution

  4. 1.4 GeV MINIBALL REX-ISOLDE From PS Booster EBIS REX-TRAP

  5. Particles • angle • energies Beam- purity Gamma- spectroscopy Beam- monitor MINIBALL Beam Dump Detector DSSSD PPAC g Univ. of Edinburgh TU Darmstadt  j q Set-up for safe Coulomb-excitation- beam B(E2) measured relative to known target B(E2) - RIB target

  6. REX-ISOLDE Physics Program • Coulomb-excitation of • 30,32Mg • (MPI Heidelberg)

  7. Coulomb excitation of 32Mg Energy [keV] H. Scheit et al.

  8. Collectivity of the Mg isotopes H. Scheit

  9. Comparison with theoretical predictions Adopted values: weighted averages without Ganil data H. Scheit

  10. Coulomb-excitation of - 74,76,78Zn - isomeric 68mCu (Univ. Leuven) REX-ISOLDE Physics Program

  11. Large scale shell model calculations Lisetskiy (MSU,GSI) J. Van de Walle et al., to be published Towards the doubly magic 78Ni- evolution of collectivity in 74,76,78Zn - E. Padilla-Rodal et al., PRL94, 122501(2005) Ge Zn Ni 78Zn: 8x103pps • 74Zn: agreement with intermediate energy Coulex (GANIL) • Steep drop in B(E2) towards N=50 • Good agreement with large scale shell model calculations

  12. LASER 6- T1/2=3.7 min (6-) 1+ - (2+) T1/2=30 s 1+ 68Cu - 68mCu: production of isomeric beams U. Koester et al., NIM B 167 (2000) 528

  13. EXP. Shell-model** (ep=1.9; en=0.9; 56Ni core) 5- 768 (5-) 628 4- 409 4- 235 B(E2)=6.5 W.u. B(E2)=6.7± 0.7 W.u. (3-) 56 3- 63 0 6- 0 6- I. Stefanescu et al., to be published Coulomb excitation of isomeric beam: 68mCu 68Ga (2+ 1+) 174 keV 68mCu (2.86 MeV/u) @ 120Sn (2.3 mg/cm2) 68Cu (4- 3-) 178 keV YMB(68mCu) ~ 3 · 105 pps 140 160 180 200 220 E [keV] p3/2g9/2 J=3-, 4- , 5- , 6- Good agreement with large scale shell model calculations (But very large effective charge!  sign for core excitations) **N. Smirnova, Private Communication

  14. Coulomb-excitation of 122,124Cd,138,140,142Xe (TU München) REX-ISOLDE Physics Program • Shape • coexistence • (70Se, 88,92Kr)

  15. program for REX-ISOLDE reduced B(E2) Minimum of Weizsäcker mass parabola for given mass number A B(E2) systematic – improved Grodzins rule 148Ba Raman systematics + isospin dependence (Habs, Krücken)

  16. 2+ → 0+ 138Xe T ~ 10 h 4+ → 2+ 96Mo 142Xe 2+ → 0+ T ~ 19 h 96Mo 4+ → 2+ 96Mo Coulomb excitation of 138,140,142Xe • ~ 105 part/s • 1.7 mg/cm2 96Mo target 140Xe T ~ 26 h 2+ → 0+ 4+→ 2+ 96Mo

  17. B(E2) values around 132Sn Two values published

  18. g-factor experiments planned in 2006/2007 B(E2) values around 132Sn T. Behrens et al. to be published • No evidence for further deviations from systematics • further experiments for 126Cd, 144Xe, 138,148,150Ba

  19. MINIBALL @ FRS middle focus:Spectroscopy in one-nucleon knock-out reactions

  20. Production via Momentum distribution MINIBALL At reaction target determines angular momentum Online Gamma-Spectrum (~7 days) 55Ti New transition observed 3/2- 5/2- 3/2- 1/2- 1/2- 5/2- • Different model predictions: • Different ground state spin (L=1 or 3) • Different order of states KB3G GXPF1A Gamma spectroscopy in knock-out reactions P. Maierbeck (TUM) 86Kr 450 MeV/u vom SIS18 56Ti ~5 s-1 55Ti ?

  21. Summary and Outlook • MINIBALL @ REX-ISOLDE • Very productive ongoing experimental program • Evolution of collectivity studied via safe Coulomb excitation • 30,32Mg: border of the N=20 island of inversion • 74,76,78Zn, 68mCu: probing large scale shell model near 78Ni • 122,124Cd, 138,140,142Xe: evolution of collectivity around 132Sn • experiments just performed on 80Zn and 144Xe • Good agreement with shell model (N=20,50) or systematics (A~140) • First transient field g-factor measurements at REX this fall (138Xe) • Transfer experiments with new detector set-up  V. Bildstein (TUM) • MINIBALL @ FRS middle focus: towards R3B @ FAIR • High resolution spectroscopy in relativistic knock-out reactions with low beam intensities  towards the extremes of isospin • Measurement of recoil momentum  s.p. angular momentum • Successful measurements for 47Ca, 55Ti, 73Cu (analysis in progress)

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