1 EUNPC2015Aug 30 - Sep 4, 2015 LIFETIME MEASUREMENTS TO STUDY THE NATURE OF EXCITED STATES BEYOND N=50 AGATA + GANIL Andrea Gottardo

2 Sr88 Rb87 Kr86 Br85 Se84 As83 Ge82 Ga81 Zn80 Cu79 Ni78Ni77Ni71Ni72Ni73Ni74Ni75Ni76Ni70 Ge76 Ge74 Y89 Zr90 As75 Se76Se77Se78Se80Se82 Br79Br81 Kr78Kr80Kr82Kr83Kr84 Rb85 Sr86Sr87Sr84 Zr91 Zr93Zr92 Zr93 Zr94 Zr95 Zr96 50 the case of the light N=51 odd isotones Courtesy of D. Verney

3 D. K. Sharp et al., PRC 87, (2013) SM calculations in valence space above 78 Ni K. Sieja et al. PRC 79, (2009) From Duflo Zuker PRC 59, R2347 (1999) Input to the calculation (necessarily taken from experimental indications) Courtesy of D. Verney

4 (1/2+)?  -decay at Orsay O. Perru et al. Eur. Phys. J. A 28, 307 (2006) from (d,p) Oak Ridge : J. S. Thomas et al. PRC 76, (2007) and  n-decay at Orsay : M. Lebois PRC 80, (2009) 2 + d 5/2 0 + s 1/2 Structure of the odd N=51 nuclei: natural laboratory for the study of the neutron structure above N=50 d 5/2 Courtesy of D. Verney

5 Target 9 Be 1,85 mg/cm 2 (10 µm) Degrader 24 Mg 5 mg/cm 2 Beam 238 U 6.2 MeV/u I  0.5 pnA  >28° MWPPAC - ToF Drift chambers – x,y,θ,φ Dipole Quadrupoles d Ionisation chambers- ΔE E res ~2600 evt/s on focal plane Fusion-fission reaction 238 U + 9 Be Excitation energy ~45 MeV Y( 83 Ge)=0.009/200= from M. Caamaño et al., Phys. Rev. C 88, (2013) and erratum fission rate  10 5 /s 3 distances 3 days each to γ/s/crystal AGATA (24 capsules) at “semi closed” distance 233 mm – 52 mm= 181 mm  ε 1 MeV  4.5% Courtesy of D. Verney

6 Modified from V. Modamio Be target stretched Micrometric Motor Mg degrader stretched Be target Mg degrader

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8 E ΔEΔE Atomic number and mass near line !

9 86 Se (no half life yet published)

10 80 Ge 82 Ge 83 Ge 2 + -> > μm

11 Br85 Se84 As83 Ge82 Ga81 Zn80 Cu79 Ni78 50 Neutron-proton gap evolution towards N = 50 EXILL; Phys Rev C 91, (2015) CLARA-PRISMANucl. Phys. A 893 (2012) 1–12

keV t 1/2 = 77(10) ps Gamma spectrum at 100μm distance: Improving Doppler correction Cleaning background The premilinary lifetime anlysis shows long- living low-lying states: feeding as expected ! Comparison with shell-model calculations 323 keV 9/2 - 11/2 - 15/2 - 13/ As

13 Stable 238 U beam from GANIL accelerator Analysis on going with promising results even in the most exotic (poor statistics) channels VAMOS excellent selectivity for the fusion-fission channels (viable mechanism towards the Ni region) Sensitivity (efficiency and peak-to-total) of the AGATA + OUPS setup crucial for weak channels

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