1. Lifetime measurements from EXILL-FATIMA campaign Pietro Spagnoletti University of the West of Scotland

2. Shape coexistence in A ~ 100 region

4. 0+0+ 2+2+ 4+4+ 0+0+ 2+2+ 4+4+ g.s. 1223 1436 1744 2048 2277 Ground state band Deformed band (relative energy ratio) 0+0+ 0+0+ 2+2+ 4+4+ 4+4+ 2+2+ 6+6+ g.s. 212 564 1062 331 878 1414 98 Zr 100 Zr Ground state band Band built on excited 0 + level (relative energy ratio)

5. EXILL-FATIMA EXOGAM@ILL – Fast Timing Array Prompt Gamma ray spectroscopy following neutron induced fission reactions Cold neutron flux 5*10 7 n s -1 cm -2 235 U Target 0.8mg cm -2 (σ capture =99b) 8 EXOGAM Clover Detectors 16 LaBr3(Ce) fast scintillators Measurement of lifetimes >10ps Photo taken from: N. Saed-Samii, Diploma thesis, University of Cologne

6. EXILL-FATIMA EXOGAM@ILL – Fast Timing Array Prompt Gamma ray spectroscopy following neutron induced fission reactions Cold neutron flux 5*10 7 n s -1 cm -2 235 U Target 0.8mg cm -2 (σ capture =99b) 8 EXOGAM Clover Detectors 16 LaBr3(Ce) fast scintillators Measurement of lifetimes >10ps Photo taken from: N. Saed-Samii, Diploma thesis, University of Cologne

7. * 411keV 344keV 0+0+ 2+2+ 4+4+ 152 Gd CFD TAC Delay LaBr(Ce) Scintillation Detectors Start Stop DAC Mirror Symmetric Centroid Difference 3-3- 368keV EXOGAM

8. CFD TAC Delay LaBr(Ce) Scintillation Detectors Start Stop DAC * 411keV 344keV 0+0+ 2+2+ 4+4+ 152 Gd Mirror Symmetric Centroid Difference Figure adapted from - J.-M Regis et al., Nucl. Instr. And Meth A 622 (2010) 83-92 J.-M Regis et al., Nucl. Instr. And Meth A 763 (2014) 210-220

9. Analysis – First excited 2 + level of 100 Zr Test case High fission yield Even-even nucleus Measured several times previously Relatively long lifetime Mirror symmetric centroid shift method and exponential decay measurements possible 4+4+ 6+6+ 212keV 564keV 1061keV 0+0+ 2+2+ 100 Zr 497keV 352keV 212keV

10. Analysis 4+4+ 6+6+ 212keV 564keV 1061keV 0+0+ 2+2+ 100 Zr 497keV 352keV 212keV 4 + → 2 + 2 + → 0 +

11. Cut into the feeding transition for both the start and stop FT- matrices. Must determine to contribution from the background to the centroid shift. Measurement of centroid shift at energies above feeding transition.

12. TAC stop TAC start B(E2; 0 + → 2 + ) exp = 83(1)W.u. B(E2; 0 + → 2 + ) ensdf = 75(4)W.u.

13. TAC stop TAC start B(E2; 0 + → 2 + ) exp = 83(1)W.u. B(E2; 0 + → 2 + ) ensdf = 75(4)W.u.

14. 99 Zr 121.7 252.0 657.9 850.5 1065.7 1038.5 1255.9 1507.4 1970.8 1802.6 1236.6 821.6 614.1 678.6 667.5 g.s. 1322.8 1892.8 1585.5 T 1/2 =54ns 575.7

15. 99 Zr 121.7 252.0 657.9 850.5 1065.7 1038.5 1255.9 1507.4 1970.8 1802.6 1236.6 821.6 614.1 678.6 667.5 g.s. 1322.8 1892.8 1585.5 T 1/2 =54ns 575.7 W. Urban, J.A. Pinston, et al., Eur. Phys. J. A 16, 11-15 (2003) 3 different deformations present within 1MeV Spherical at low energy

16. 99 Zr 121.7 252.0 657.9 1038.5 1255.9 1507.4 1970.8 1802.6 1236.6 821.6 614.1 678.6 667.5 g.s. T 1/2 =54ns Excited state at 1038.5keV interpreted to be K-isomer. 9/2[404] neutron hole excitation Large deformation β 2 =0.41

17. 135 I 135 I 82 1134 1421 1994 4+4+ 6+6+ 1279 1576 1691 0+0+ 2+2+ 134 Te 82 0+0+ 2+2+ 136 Xe 82 4+4+ 6+6+ 1313 1694 1791

18. Summary and Future work Analysis ongoing Lifetime measurements of excited states in three different bands of 99 Zr performed Two lifetime measurements for excited states of 135 I performed Calculations of reduced transition probabilities still to be done Analysis of 97 Sr, 98 Sr, 133 I and other Analysis of data produced from 241 Pu target Fission product yield

19. Thanks to the EXILL-FATIMA Collaboration TU Darmstadt, Germany S. Ilieva, S. Bönig, A.-L. Hartig, C. Henrich, A. Ignatov, Th. Kröll, M. Thürauf Universität zu Köln, Germany J. Jolie, J.-M. Régis, N. Saed-Samii ILL, Grenoble, France A. Blanc, M. Jentschel, U. Köster, P. Mutti, T. Soldner, W. Urban GANIL, France G. de France IPHC Strasbourg, France R. Lozeva University of the West of Scotland, Paisley, UK M. Scheck, G. Simpson, J. F. Smith, P. Spagnoletti CSNSM Orsay, France C. Petrache, R. Leguillon, T. Zerrouki, S. Kaim, Ks. Rezynkina IFIN-HH, Bucharest, Romania N. M˘arginean, D. Filipescu, I. Gheorghe, D. Ghita, R. Lica, R. M˘arginean, C. Mihai, S. Toma University of Surrey, Guildford, UK P.H. Regan, R. Carroll, Zs. Podoly´ ak, C. Townsley, P. Walker, W. Catford, T. Alharbi Universidad Complutense, Madrid, Spain L. M. Fraile, V. Paziy...