1. Exploring life-time of low-lying states in neutron-rich nuclei towards 78Ni with the plunger technique at GANIL B. Mouginot (IPN-Orsay) E. Fiori, G. Georgiev, R. Lozeva : CSNSM, orsay L. Gaudefroy : CEA, Bruyères-Le-Chatel M. Amthor, M.Assie, G.Burgunder, L. Caceres, E. Clément, G. De France, F. de Oliveira, A. Dijon, S. Grevy, M. Harakeh, C. Stodel, J.C. Thomas, P. Ujic : GANIL, Caen C. Borcea, A. Buta M. Catalin, F. Negoita, D. Pantelica, F. Rotaru : IFIN-HH, Bucharest P. Bednarczyk, M. Kmiecik, A. MAJ, S. Myalski : IFJ PAN, Krakovi L. Coquard, O. Moeller : IKP, Darmstadt A. Dewald, C. Fransen, G. Friessner, M. Hackstein, T. Pissula, W. Rother, : IKP, Universität zu köln F. Azaiez, S. Franchoo, F. Ibrahim, I. Matea, B. MOUGINOT, M. Niikura, L. Perrot, J. A. Scarpaci, I. Stefan, D. Verney : IPN, Orsay G. de Angelis : LNL INFN, Legnaro A. Burger : University of Oslo

2. Se84 As83 Ge82 Ga81 Zn80 Cu79 Ni78 Zn78Zn76 Ni74Ni76Ni72Ni70Ni68Ni66 Cu65 Zn66Zn67Zn68Zn70 Ge70Ge72Ge73 Se74 Ge74 Ga69Ga71 Se76Se77Se78 As75 Se80Se82 Ni64 Ge76 50 28 Zn74Zn72 Ge78Ge80 50 28 f 5/2 p 3/2 p 1/2 g 9/2 d 5/2 s 1/2 d 3/2 g 7/2 f 7/2 g 9/2 p 1/2 h 11/2  74 Zn EURORIB 2010

3. Present Knowledge : J Van de Walle et al Physical Review Letters 99, 142501 (2007) Physical Review C 79, 014309 (2009) O Perru et al Physical Review Letters 96, 232501 (2006) B.MOUGINOT, IPNOEURORIB 2010 2+ energy (from Z=26 to 34) B(E2) strength (from Z=28 to 34) N.J. Stone, Atomic Data and Nuclear Data Tables 90 (2005) 75-176 Evolution of the neutron orbital energy as fonction of the deformation parameter  Proton core polarisation E(2+) flatness Region of possible deformation 74 Zn Fermi Level K quantum number: 1/2 3/2 5/2 7/2 9/2 Enhance collectivity with Z number Oblate Prolate

4. How the Q/  will evolve in more neutron rich Zn isotopes? In this presentation I will focus on 74Zn Known Quadrupole Moment : B.MOUGINOT, IPNOEURORIB 2010 N.J. Stone, Atomic Data and Nuclear Data Tables 90 (2005) 75-176 Q Moment  Deformation parameter

5. 74Zn secondary beam Production with LISE @GANIL : 76 Ge @ 60MeV/u Be 580um production-target Cocktail beam Be 450um Degrader Slits B1B1 B2B2 Selection …To D6 IDENTIFICATION D4 D4->D6 Ionisation Chamber Plastic dEE B3B3 B3B3 PRODUCTION From D4… D3->D4 Plunger 74 Zn @ 34MeV/u 1.5 e 5pps Beam selection EXOGAM TOF D4-D6 MCP EXOGAM Plunger

6. 8 EXOGAM Clovers : 4 at 45° and 4 at 135° 74 Zn CD 2 34mg/cm 2 Be 54mg/cm 2 Identification  ’’   ’ =0.2 74 Zn* EXOGAM D EXOGAM and PLUNGER : Cologne PLUNGER B.MOUGINOT, IPNOEURORIB 2010

7. After DegraderBefore Degrader 72 Zn Contamination 74 Zn component Energy [keV] Spectrum Doppler corrected forward angle Rate before degrader Rate after degrader Emission rate before and after degrader Experimental Spectrum : B.MOUGINOT, IPNO 74 Zn CD 2 Be  ’’   ’ =0.2 74 Zn* D

8. Determination of Intensity : >Peak deconvolution : fit with 4 gaussians : - 2 components for 74 Zn (before and after degrader) - 2 components for 72 Zn (...) Doppler corrected Spectrum for  2 (EXOGAM forward angle) after degrader component before degrader component after degrader component before degrader component 74 Zn 72 Zn B.MOUGINOT, IPNOEURORIB 2010

9. Preliminary First Result :  = 24(2)ps B(E2,0+->2+) = 0.209(17)e 2 b 2 B.MOUGINOT, IPNOEURORIB 2010

10. From J.Van De Walle Ph.D Quadrupole Moment : B.MOUGINOT, IPNOEURORIB 2010 0.209(17)e 2 b 2 Coulex Measurement >> Q s = -0.09(25)b 2  =0,04(11) Prolate Oblate

11. Results : Our measurement is consistent with the coulex estimation in 74Zn² B.MOUGINOT, IPNOEURORIB 2010

12. Comparison with model  Deformation parameter B(E2) strength -HFB calculation reproduces well N~44 the experimental data where it is supposed to be collective (mid-shell) -Still too much collectivity around N=40 & N=50 B.MOUGINOT, IPNOEURORIB 2010 J.-P Delaroche Physical Review C N=40

13. Conclusion : -Feasibility of plunger technique using in-flight secondary beams and secondary reactions with LISE spectrometer -> Preliminary Life-time measurement of 2+ state in 74 Zn : 24(2)ps -> Constraint on the beta deformation parameter : Beta = 0.04(11) B.MOUGINOT, IPNOEURORIB 2010 -Result for 72 Zn is under analysis. -More accurate value of the Q moment will be extracted for 74 Zn and compared to model predictions (HFB and shell model calculations).

14. THANK YOU B.MOUGINOT, IPNOEURORIB 2010