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Isomer spectroscopy below 100 Sn

Isomer spectroscopy below 100 Sn. Andrey Blazhev University of Cologne. Shell Model as a Unified View of Nuclear Structure 8-10 October 2012, Strasbourg. Outline. Introduction RISING S352 Experiment Isomers in 98 Cd, 94 Pd, 96 Ag and 96 Cd Summary and Outlook. Introduction.

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Isomer spectroscopy below 100 Sn

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  1. Isomer spectroscopy below 100Sn Andrey Blazhev University of Cologne Shell Model as a Unified View of Nuclear Structure 8-10 October 2012, Strasbourg

  2. Outline • Introduction • RISING S352 Experiment • Isomers in 98Cd, 94Pd, 96Ag and 96Cd • Summary and Outlook

  3. Introduction N=Z line Adapted from The NNDC Chart of The Nuclides Adapted from The NNDC Chart of The Nuclides

  4. Isomers in the 100Sn region • Importance of isomers • Test of the shell model • Single-particle structure • Residual interaction • Astrophysics • Properties of isomers • Existence • Excitation energy • Halflife (transition strength) • Spin and parity • γ-decay cascades • Particle decays

  5. Main goals of the RISING S352 experiment K. Ogawa, Phys. Rev. C 28, 958, (1983) A. B. et al., PRC 69 064304 (2004)

  6. Z A/Q RISING S352 Experimental Setup Stopped RISING Primary beam 124Xe @ 0.85 GeV/u Active stopper 98Cd 98Cd 96Ag 94Pd

  7. 98Cd-gated Ge-spectrum Gate 4157

  8. 98Cd (12+) isomer halflife (preliminary) 4207 keV: T1/2 = 226(30) ns 4157 keV: T1/2 = 230(80) ns Literature: T1/2 = 230 (+40−30 ) ns (A. B. et al., Phys. Rev. C 69, 064304 (2004))

  9. 98Cd high-energy level scheme B(E4; 12+→ 8 +) = 3.0(10) W.u. B(E2; 12 +→ 10 +) = 2.1(13) W.u. A. B. et al., J. Phys.: Conf. Ser. 205 (2010) 012035. A. B. et al., Phys. Rev. C 69, 064304(2004)

  10. 56Ni - 100Sn similarities H. Grawe, M. Lewitowicz, Nucl. Phys. A693, 116 (2001)‏

  11. 98Cd Shell Model • ´´standard´´ d5/2 - g7/2 sequence • ● LSSM-gds t=1,5 • p νg9/2d5/2g7/2d3/2s1/2 • ● SM-ph-pgdstruncatedto 1p1h in anyorbit in the model spaces: • pgdg: • p νp3/2f5/2p1/2g9/2d5/2g7/2 • pgndg: • p νp3/2f5/2p1/2g9/2 νd5/2g7/2 • TBME from OXBASH (SNA+GF)* • SPE tunedto100Sn Calculations: F. Nowacki H. Grawe

  12. 98Cd SM Calculations 2 98Cd ´´reversed´´ g7/2 - d5/2 sequence EXP: ΔE(d5/2 - g7/2 ) = 0,172 MeV D.Severyniaket al., PRL99 (2007) 022504 Code: Nushell@MSU [1] W.D.M. Rae, unpublished, (2007) [2] B. A. Brown and W. D. M. Rae, MSU-NSCL report (2007) Interaction: SNET Model space: SNE πν – f5/2pgds + vh11/2 Truncation: πν – f5/2p – fullyoccupied xn-ph = νg9/2-x (d5/2,g7/2)x 101Sn 11/2 - 11 + 3/2 + 12 + 1/2 + 13 + 14 + 10 + MeV 7/2 + 9 + 5/2 + Calculations: A.B.

  13. 98Cd EXP vs SM .

  14. 94Pd isomer spectrum 324 96 660 814 905 995 1092 347 745 • N. Mărginean et al., Phys.Rev C 67, • 061301(R) (2003) T.S. Brock et al., PRC 82, 061309(R) (2010)

  15. 94Pd observed transitions * 1651 1545 106 1651 267 * 408 106 C. Plettner et al., Nucl. Phys. A 733, 20-36 (2004) T.S. Brock et al., PRC 82, 061309(R) (2010)

  16. 94Pd new isomer halflife t1/2= 197(22) ns T.S. Brock et al., PRC 82, 061309(R) (2010)

  17. SM-GF: shell model calculation using the empirical interaction of Gross & Frenkel for πν(p1/2,g9/2). SM-FPG: also includes πν(f5/2,p3/2) using SNA interaction from OXBASH. Excitations from fp space restricted to 1p1h. 94Pd Shell Model Calculations 7211 106 1651 Calculations H.Grawe T.S. Brock et al., PRC 82, 061309(R) (2010)

  18. SM-GF: shell model calculation using the empirical interaction of Gross & Frenkel for πν(p1/2,g9/2). SM-FPG: also includes πν(f5/2,p3/2) using SNA interaction from OXBASH. Excitations from fp space restricted to 1p1h. 7211 106 1651 94Pd Shell Model Calculations Bexp (E1)= 0.3(1) μW.u. Calculations H.Grawe Bexp(E3)= 0.28 W.u. +0.04 -0.03 Btheo(E3)= 0.15 W.u. T.S. Brock et al., PRC 82, 061309(R) (2010)

  19. 0.16(3) s new known: R. Grzywacz et al. PRC 55 (1997) 1126 B(E4; 19+15+) = 0.9(6) W.u. B(E2; 19+ 17+) = 4.7(10) W.u. 4168 Counts SE 4264 E[keV] 1.56(3) s 100(10) s B(E3; 13- 10+) = 0.145 (17) W.u. P. Boutachkov et al., Phys. Rev. C 84, 044311 (2011) Isomers in 96Ag Tf<1 s

  20. 96 Ag 47 49 E[MeV] 1.56(3)ms 100(10)ms Shell Model Calculations: H.Grawe GF:model space: pn(g9/2, p1/2) 1p-1hinteraction: R.Gross and A.Frenkel,NPA 267(1976)85→ 13-, 15+ isomers fpg: GF+ SNA pn 1p-1h excitation from f5/2 and p3/2 TBME from OXBASH package (SNA+GF) and SPE tuned to 100Sn P. Boutachkov et al., Phys. Rev. C 84, 044311 (2011)

  21. 96 Ag 47 49 B(E4) = 0.9(6) W.u B(E4) = 0.7 W.u B(E2) = 4.7(10) W.u B(E2) = 3.6 W.u B(E2) = 4.3 W.u B(E2) = 2.5-6.6 W.u B(E2) = 4.3 W.u Calculations: GF, FPG – H.Grawe LSSM GDS – F. Nowacki, K. Sieja B(E3) = 0.13 W.u B(E3) = 0.145(17) W.u P. Boutachkov et al., Phys. Rev. C 84, 044311 (2011)

  22. 96 98 0.16(3) ms Ag Cd 47 48 49 50 0.23(8) ms B(E2; 19+ 17+) = 4.7(10) W.u. B(E4; 19+ 15+) = 0.9(6) W.u. B(E2; 12+ 10+) = 2.1(13) W.u. B(E4; 12+ 8+) = 3.0(10) W.u. 4264

  23. 96Cd – beta decay 96Cd, t = 0 – 0.2 s 96Cd, t = 0.2 – 4 s 96Cd, t = 0.2 – 4 s T1/2 (421) = 0.67  0.15 sec, T1/2 (470, 1506, 667) = 0.29 + 0.11 sec – 0.10 B.S. Nara Singh et al., PRL107, 172502 (2011)

  24. 0.16(3) s B(E4; 19+15+) = 0.4(3) W.u. B(E2; 19+ 17+) = 4(3) W.u. 1.56(3) s 100(10) s B(E3; 13- 10+) = 0.187 (20) W.u. P. Boutachkov et al., Phys. Rev. C 84, 044311 (2011) Spin-gap isomer 96Cd 16+ 0.29 s B.S. Nara Singh et al., PRL107, 172502 (2011) β+ 0+ 0.67 s 1.03 s  20%,Bazin et al PRL 101, 252501 (2008) 96Cd β+ SM predictions: (p1/2,g9/2) Int. J Ex (keV) GF 1+ 356 2+ 12 SLGT0 1+ 382 2+ 0 (1+) 421? 96Ag 2+

  25. Isomers below 100Sn (summary) H.Grawe

  26. Summary and outlook • 98Cd new level (10+ ) and Exp. B(E4) and B(E2) estimates of the (12+ ) depopulating transitions • 94Pd a new high-spin (19- ) E3 isomer • 96Ag – 3 isomeric states (E4, E3, E2) incl. core excited, extended level scheme • 96Cd – 16+ Spin-gap isomer confirmed in beta decay • LSSM-GDS, FPG and GF calculations complement to describe isomerism in the region • Exp. search for the 14+ in 98Cd and if possible reproduce level ordering by SM • Search for and clarify direct particle decays in the region, esp. from isomers • Direct mass measurements of “long lived” isomers without gamma decay • Possible Coulex experiments on gs. and isomeric beams of key isotopes

  27. Collaboration Ayse Atac, Linus Bettermann, Andrey Blazhev, Plamen Boutachkov, Norbert Braun, Tim Brock, Lucia Caceres, Cesar Domingo, Tobias Engert, Katrin Eppinger, Thomas Faestermann, Fabio Farinon, Florian Finke, Kerstin Geibel, Jurgen Gerl, Namita Goel, Magda Gorska, Andrea Gottardo, Hubert Grawe, Jerzy Grebosz, Christoph Hinke, Robert Hoischen, Gabriela Ilie, Hironori Iwasaki, Jan Jolie, Ivan Kojouharov, Reiner Krucken, Nikolaus Kurz, Zhong Liu, Edana Merchant, B. S. Nara Singh, Chiara Nociforo, Frederic Nowacki, Johan Nyberg, Marek Pfutzner, Stephane Pietri, Zsolt Podolyak, Andrej Prochazka, Patrick Regan, Peter Reiter, Sami Rinta-Antila, Dirk Rudolph, Clemens Scholl, Kamila Sieja, Par-Anders Soderstrom, Steve Steer, Robert Wadsworth, Nigel Warr, Hans-Jurgen Wollersheim, Philip Woods

  28. Thank you

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