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Nele Kesteloot

Coulomb excitation of 196,198,200,202 Po studied at REX-ISOLDE with the Miniball γ spectrometer. Nele Kesteloot

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Nele Kesteloot

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  1. Coulomb excitation of 196,198,200,202Po studied at REX-ISOLDE with the Miniball γspectrometer Nele Kesteloot B. Bastin, Y. Blumenfeld, N. Bree, P. Butler, E. Clement, J. Diriken, A. Dorsival, V. Fedosseev, L. Gaffney, T. Giles, T. Grahn, A. Herlert, M. Huyse, J. Iwanicki, J. Konki,T. Kröll, R. Krucken, B. Laurent, N. Lecesne, B. Marsh, P. Molkanov, E. Piselli, E. Rapisarda, P. Reiter, M. Scheck, M. Seidlitz, M. Seliverstov, M. Sferrazza, B. Siebeck, M. Sjodin, T. Stora, J. Taprogge, H. Tornqvist, E. Traykov, J. Van de Walle, P. Van Duppen, D. Voulot, N. Warr, F. Wenander, K. Wrzosek and M. Zielinska

  2. Outline • The polonium isotopes • The Miniballdetectionsetup • 200Po as test case • Main experiment: 196-202Po • Futureperspectives BriX-IAP Workshop 2013 - Oostende

  3. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives The polonium isotopes A.M. Oros et al NPA 645:107 (1999) (π1h9/2)2 R. Julin et al JPG 27:R109 (2001) Shape coexistence Generalized seniority Change in nuclear structure T.E. Cocolios et al. PRL 106:052503 (2011) M.D. Seliverstov et al., in preparation N = 116 Transition expected around 200Po BriX-IAP Workshop 2013 - Oostende

  4. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives Why Coulomb excitation? R. Julin et al, JPG 27 (2001) R109 K. Helariutta et al, EPJA 6 (1999) 289 A. Maj et al, NPA 509 (1990) 413 W. Younes et al, PRC 52 (1995) R1723 At Po Rn Z = 85 Z = 84 Z = 86 In beam αdecay Lifetimemeasurements N. Bijnens et al, PRL 75 (1995) 4571 J. Wauters et al, PRL 72 (1994) 1329 T. Grahn et al, PRL 97 (2006) 062501 T. Grahn et al, PRC 80 (2009) 014323 Laser spectroscopy β decay T.E. Cocolios et al PRL 106,052503 (2011) N. Bijnens et al, PRL 75 (1995) 4571 Coulomb excitation BriX-IAP Workshop 2013 - Oostende

  5. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives The Miniball detection setup EP θP 200Po 570 MeV target 104Pd2 mg/cm2 ET BriX-IAP Workshop 2013 - Oostende

  6. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives 200Po as test case: Kinematics Particleparticle gamma events for200Po on 104Pd 104Pd 200Po BriX-IAP Workshop 2013 - Oostende

  7. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • 200Po as test case: Results Particleparticle gamma spectrum, Doppler correctedfor200Po/104Pd 556 keV 2+0+104Pd Xrays 666 keV 2+0+200Po Counts/1keV BriX-IAP Workshop 2013 - Oostende

  8. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • 200Po as test case: Xrays 1392.3 2+ 1276.9 4+ 1136.5 0+ X rays Conversion of 2+0+ 665.9 2+ 1.88(13).104 αK = 0.0125  856(23) 0 0+ 200Po Atomic production of K vacancy in ion-atom collision Internal conversion of other gamma lines Other gammas unobserved BriX-IAP Workshop 2013 - Oostende

  9. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • 200Po as test case: Xrays • Theoretical formula • Empirical correction • Based on experimental data in Po region • Comparison with Hg coulex data • Geometrical correction • Range of particle detector • Estimate: 0.56(21).104 J.D. Garcia et al, RMP 45 No 2 (1973) 111 Range particle detector BriX-IAP Workshop 2013 - Oostende Method: N.Bree 2010

  10. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • 200Po as test case: Xrays 1392.3 2+ 1276.9 4+ 1136.5 0+ X rays Conversion of 2+0+ 665.9 2+ 1.88(13).104 αK = 0.0125  856(23) 0 0+ 200Po Atomic production of K vacancy in ion-atom collision Internal conversion of other gamma lines Theoretical formula + corrections Other gammas unobserved 0.56(21).104 Method: N.Bree 2010 PRELIMINARY E0 transition 0+2 0+1  1.24(24).104 BriX-IAP Workshop 2013 - Oostende

  11. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • 200Po as test case: Results • Analysis in final stage • BUT: on hold • Preliminary result for atomic X rays used • <0+1||E2||2+1> is stable • B(E2;0+2+) = 35(5) W.u. • <2+1||E2||2+1> is negative • Large uncertainty • Consistent with zero BriX-IAP Workshop 2013 - Oostende

  12. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives Main experiment: 196-202Po:Typical gamma spectra pγ + ppγ events, Doppler correctedforprojectile/target 463 keV 2+0+196Po 605 keV 2+0+198Po 198Po on94Mo 196Po on104Pd 556 keV 2+0+104Pd 871 keV 2+0+94Mo 556 keV 2+0+104Pd 556 keV 2+0+104Pd 200Po on104Pd 202Po on 104Pd 666 keV 2+0+200Po 677 keV 2+0+202Po BriX-IAP Workshop 2013 - Oostende

  13. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives • Main experiment: Xrays: 202Po 556 keV 2+0+104Pd 1302.5 2+ 1248.6 4+ 677.2 2+ 0 0+ 202Po 677 keV 2+0+202Po Atomic Xrays α=0.0162 Use202Po as scaling nucleus BriX-IAP Workshop 2013 - Oostende

  14. The polonium isotopes The Miniballdetection setup 200Po as test case Main experiment: 196-202Po Futureperspectives Future perspectives • Experimental campaigns (2009 and 2012) very succesful • Analysis will yield a lot of information • B(E2;0+2+) values of 196,198,200,202Po • Quadrupole moments of first 2+ state in 196,198,200,202Po • Comparison of our B(E2;0+2+) value for 196Po with result from lifetime experiment T. Grahn et al, PRC 80 (2009) 014323 • Parasitic information on196Tl • Resultswillbecompared to theoretical models • Beyondmean field calculations • Symmetryguided models BriX-IAP Workshop 2013 - Oostende

  15. Thank you for your attention!

  16. Main experiment: 196Po 891 4+ 859.1 2+ 558 0+ 463.1 2+ 196Po 0 0+ 196Po Xrays pγ + ppγevents Doppler correctedfor196Po 196Tl 196Tl 2-ground state7+isomer 196Po 104Pd BriX-IAP Workshop 2013 - Oostende

  17. Parasitic data on 196Tl 394.2 7+ Single gamma spectrum 0 2- 196Tl 5-,6,7- 2346 505 426 keV 7- 1841 5- 1757 695 Counts/keV 1061.6 4+ 635 keV 505 keV 1036.2 1+,2+ 695 keV 635 611 2+ 426.3 426 611 keV 0 0+ 196Hg Energy (keV) BriX-IAP Workshop 2013 - Oostende

  18. 196Tl level scheme BriX-IAP Workshop 2013 - Oostende

  19. 196Tl decay BriX-IAP Workshop 2013 - Oostende

  20. Ranges in Gosia Particle detector Obtain sensitivity on the diagonal matrix element of the first excited state by scanning the center of mass range! BriX-IAP Workshop 2013 - Oostende

  21. Summary of information BriX-IAP Workshop 2013 - Oostende

  22. Unobserved transitions: upper limits • Upper limit = number of counts that would give rise to a peak above the background • Same integration window as in main peak (30 keV) • UPL = N + 3σ • Correct for detection efficiency 611keV transition:UPL = 587 cts 666 keV transition:N = 8.31(10).103 cts BriX-IAP Workshop 2013 - Oostende

  23. First order solution in Gosia 2 • Disregard X rays and higher lying states • Normalize projectile to target excitation • <0+||E2||2+> = 1.03(8) eb • <2+||E2||2+> = 0.55 eb • = starting point for Gosia 1 2+ 666 8.79(10).104 0+ 200Po <2+||E2||2+> [eb] 2+ 556 1.762(15).105 0+ <0+||E2||2+> [eb] 104Pd BriX-IAP Workshop 2013 - Oostende

  24. Gosia 1 • Gosia input • 6 experiments • 5 experiments for 5 angular ranges (no X rays) • 6th experiment with total yield for 2+0+ and X rays • 6 states • Virtual 1+ state to simulate E0 transition • 2 buffer states • 9 data points • 7 yields • 1 known branching ratio • 1 known matrix element (<0+||E2||2+> = 1.03(8) eb) • 7 free matrix elements • Couple <0+1||E2||2+1> and <2+1||E2||4+1> • Treat virtual M1 matrix elements as one matrix element BriX-IAP Workshop 2013 - Oostende

  25. Gosia 1: solutions BriX-IAP Workshop 2013 - Oostende

  26. Gosia analysis E0 Unobserved Upper limit Conversion coefficient BR=1.16(42) 5944 • Normalisation to target excitation • Virtual 1+ state • Buffer states 0.11 α=0.11 1086 1715 α=0.01479 5944 18112 1.3(2).104 α=0.0126 8.8(1).104 Gosia: T. Czosnkyka, D. Cline, C.Y. Wu Bull. Amer. Phys. Soc. 28, 745 (1983) BriX-IAP Workshop 2013 - Oostende

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