Lifetime Measurements in N=Z 72 Kr

1. International Conference on Finite Fermionic Systems ― Nilsson Model 50 YearsJune 14-18, 2005, Lund, Sweden Lifetime Measurements in N=Z72Kr Corina Andreoiu

2. Outline • Motivation • Experimental set-up • Results & Discussions • Conclusions

3. 4 Delayed Alignments? 2 π(g9/2)2 x ν(g9/2)2 Band 2-4: Δτ = 50 fs 14(5) fs 61(16) fs Qt = 1.15(15) eb 4 1 400(150) fs Qt = 2.52(47) eb β = 0.37 G. de Angelis et al. Phys. Rev. Lett. B 415, 217 (1997) S. Fischer et al. Phys. Rev. Lett. 87, 132501 (2001) N. Kelsall et al. Phys. Rev. C 64, 024309 (2001)

4. ix(ħ) ħω (MeV) Alignments in 72,74,76Kr

5. no pairing pairing A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press Theoretical StudiesKinetic Moments of Inertia CRHB + LN, Gogny D1S (T = 1) Pairing

6. Labelled: number of protons in g9/2 orbital number of neutrons in g9/2 orbital  [p,n] eν(MeV) β2/β4 Neutron Single Particle Levels W. Nazarewicz et al. Nucl. Phys. A345, 397(1985)

7. band 2 band 4 Configurations A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

8. [2,2] [3,3]a [3,3]b Transitional Quadrupole Moment and Deformation CRHB + LN CRMF A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

9. Z=36 Kr Nuclei Z N=Z Argonne National Laboratory, Chicago, USA 40Ca + 40Ca → 80Zr → 72Kr + 2α Beam: 40Ca @ 164 MeV Target: 350 μg/cm2 40Ca 150 μg/cm2197Au 80 40 Zr CN 78 79 39 Y 77 76 78 38 Sr 74 75 76 77 Ru 37 74 75 76 72 73 36 Kr 2a 74 73 75 72 71 70 35 Br 70 69 71 72 73 74 68 Se 34 39 40 36 37 38 34 35 N

10. Microball 95 CsI(Tl) scintilators 9 rings • Identification of charged particles Channel selection • Energy, momentum and angle of the charged particles  Event by event kinematic reconstruction D.G. Sarantites et al. NIM A381,418 (1996)

11. Gammasphere • 110 HP Ge detectors, Compton Suppressed, 17 rings • gamma ray multiplicity • sum energy measurements • total energy conservation selection 40Ca Gammasphere detector angles + kinematics of reaction (Microball)  Doppler correction of γ rays MICROBALL I.Y. Lee, Nucl. Phys. A520, 641c, (1991)

12. 2 High Spin States in 72Kr 30+ 4 Jtop + 4 28+ 2α TEP - Band Side Band

13. band 2 band 4 Configurations A.V. Afanasjev, S. Frauendorf, Phys. Rev. C, (2005) in press

14. Low-Spin (Preliminary) Band 2 Low spin Recoil out of target

15. Band 2 – High Spin

16. Band 4

17. [2,2] [3,3]a [3,3]b Experiment & Theory CRHB + LN CRMF

18. Conclusions • Extended the level scheme of N=Z72Kr up to 30ħ • Lifetime measurements at high spins in 72Kr using the DSAM • Good agreement with theory with only T=1 (Gogny DS1) pairing Future Work • Measure lifetimes of lower spin states using backed target data

19. Acknowledgments McMaster University R.A.E Austin NSCU D. Dashdorj University of Guelph P. Finlay P.E. Garrett G.F. Grinyer B. Hyland A.A. Phillips M.A. Schumaker C.E. Svensson J.J. Valiente-Dobon TRIUMF M.B. Smith CEA Saclay A. Goergen York University D. Jenkins F. Johnston-Theasby P. Joshi R. Wadsworth Argonne National Laboratory M.P. Carpenter S.J. Freeman F. Moore D. Seweryniak Washington University W. Reviol D.G. Sarantites Lawrence Berkeley National Laboratory A.O. Macchiavelli D.D. Ward

20. Tack så mycket! Lund University The Swedish Foundation for International Cooperation in Research and Higher Education

22. Side Band Recoil out of target