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Spectroscopy of Transfermium Nuclei

Spectroscopy of Transfermium Nuclei. Andrew Robinson The University of York. Super Heavy Nuclei Transfermium Nuclei Nobelium Isotopes Experimental setup at ANL Results from 252 No N=150 Isotones Improvements to focal plane at ANL Preliminary Results 256 Rf. Liquid Drop Limit.

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Spectroscopy of Transfermium Nuclei

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  1. Spectroscopy of Transfermium Nuclei Andrew Robinson The University of York

  2. Super Heavy Nuclei Transfermium Nuclei Nobelium Isotopes Experimental setup at ANL Results from 252No N=150 Isotones Improvements to focal plane at ANL Preliminary Results 256Rf

  3. Liquid Drop Limit Super Heavy Nuclei E = ELDM + dU + dP SHE Workshop - Paisley: 12th March 2008

  4. Skyrme Relativistic Mean-Field 208Pb,209Bi(HI,1n) reaction Macroscopic / Microscopc from Morita Super Heavy Nuclei Liquid Drop Limit SHE Workshop - Paisley: 12th March 2008

  5. High-K Isomers Protons Neutrons SHE Workshop - Paisley: 12th March 2008

  6. Example: 254No S. K. Tandel et al., Phys. Rev. Lett. 87, 082502 (2006) R.-D. Herzberg et al., Nature. 442, 896 (2006) SHE Workshop - Paisley: 12th March 2008

  7. Z=102: Nobellium 1/2[620] 1/2[620] 152 100 152 7/2[514] 1/2[521] 9/2[734] 9/2[734] 7/2[624] 7/2[624] 7/2[633] 5/2[621] 5/2[621] p n SHE Workshop - Paisley: 12th March 2008

  8. 252No: Previous Results T1/2 = 2.4(3) s R.-D Herzberg et al., Phys. Rev. C 65, 014303 (2001) b2 = 0.28(2) SHE Workshop - Paisley: 12th March 2008

  9. 252No: Predictions Single-particle energies from Woods-Saxon with “Universal Parameters” Pairing Lipkins-Nogami perscription 152 100 i13/2 j15/2 h9/2 g9/2 f5/2 i11/2 SHE Workshop - Paisley: 12th March 2008

  10. Experimental Details SHE Workshop - Paisley: 12th March 2008

  11. Clover LEPS FMA e- a Fission ? Experimental Details 40x40 DSSD PGAC High Gain Preamps • DSSD Shaping Amps • High Gain ~5 Mev • Medium Gain ~10 MeV • Low Gain ~100 MeV SHE Workshop - Paisley: 12th March 2008

  12. Ebeam = 219.5 Mev Ibeam~ 120 pnA s ~ 500 nb Yu. Ts. Oganessian et al. Phys. Rev. C 64, 054606 Counts Counts PGAC-DSSD tof (arb.) PGAC dE (arb.) X position (arb.) X position (arb.) Recoil Energy (arb) X position (arb.) Experimental Details Rotating target wheel Beam defocused & wobbling SHE Workshop - Paisley: 12th March 2008

  13. Random ln T (ms) 1.2 secs Energy (keV) Results: Electrons Same Pixel ln T (ms) Energy (keV) SHE Workshop - Paisley: 12th March 2008

  14. Isomer gated g,g matrix Results: Gamma Rays Isomer correlated g-rays Eg (keV) Total g,g projection Eg (keV) Counts / 1 keV Eg (keV) SHE Workshop - Paisley: 12th March 2008

  15. Test validity of entire set of coincidences (for a rotational band) rather than individual coincidences Consider Measured Intensities of transitions Electron Sum Energy R.-D Herzberg et al., Phys. Rev. C 65, 014303 (2001) Discussion • g-ray data is too sparse (especially g,g) for conventional analysis • Ground State band from previous work (Herzberg et al.) • Construct a coherent level scheme guided by model E = EB.H + A(I(I+1)) + B(I(I+1))2 SHE Workshop - Paisley: 12th March 2008

  16. Discussion SHE Workshop - Paisley: 12th March 2008

  17. Discussion: g-rays Eg (keV) Isomer gated g,g matrix Eg (keV) SHE Workshop - Paisley: 12th March 2008

  18. Calculated e- spectrum Discussion: e- sum energy SHE Workshop - Paisley: 12th March 2008

  19. Discussion: Other Work B. Sulignano et al., Eur. Phys. J. A 33, 327 (2007) SHE Workshop - Paisley: 12th March 2008

  20. Discussion: Other Work This Work B. Sulignano et al., Eur. Phys. J. A 33, 327 (2007) SHE Workshop - Paisley: 12th March 2008

  21. Discussion 152 100 i13/2 j15/2 h9/2 g9/2 f5/2 i11/2 SHE Workshop - Paisley: 12th March 2008

  22. (8-) 979 (7-) 885 (6-) 806 (5-) 735 (4-) 677 630 (3-) 592.2 (2-) 6+ 285 4+ 137.8 2+ 41.5 0+ 0.0 N=150 Isotones I. Ahmad Priv. Comm. P.T. Greenlees Priv. Comm. S.W.Yates et al., Phys.Rev. C12, 442 (1975) This Work SHE Workshop - Paisley: 12th March 2008

  23. N=150 Isotones 8- Experimental 2- QRPA – Mod.Nilsson Parameters (Nakatuskasa) 152 100 i13/2 j15/2 h9/2 8- Woods-Saxon g9/2 f5/2 i11/2 2- Experimental SHFB – SLy4 Z=98, 104 & N=150 W.S Z=100 & N=152 SHE Workshop - Paisley: 12th March 2008

  24. Z = 104: Rutherfordium 1/2[620] 9/2[624] 152 100 100 7/2[514] 1/2[521] 7/2[514] 9/2[734] 1/2[521] 7/2[624] 7/2[633] 5/2[621] n p 7/2[633] SHE Workshop - Paisley: 12th March 2008

  25. 256Rf: Predictions 100 152 SHE Workshop - Paisley: 12th March 2008

  26. Argonne Implantation Detector Array • New close packed chamber design: minimise material between DSSD and Clovers. • More (5) Clover detectors + new compact electronics and filling system. SHE Workshop - Paisley: 12th March 2008

  27. Ebeam = 242 Mev Ibeam~ 300 pnA s ~ 12 nb F. P. Hessberger Priv. Comm. (2005) Experimental Details Rotating target wheel Beam defocused & wobbling 40x40 DSSD High Gain  e- Medium Gain  alphas Low Gain  fission New AIDA target chamber 4 Clover detectors (~9% eff at 900 keV) SHE Workshop - Paisley: 12th March 2008

  28. Preliminary Results: 256Rf Random Pixel Same Pixel ~500 fission events t1/2 = 6.8(4) ms (t1/2 ENDSF = 6.4(2) ms) SHE Workshop - Paisley: 12th March 2008

  29. Preliminary Results: 256Rf Random Pixel Same Pixel t1/2 ~ 2ms A=256e-Fision(6.8ms) 8 events t1/2 ~ 100ms Counts / 10 keV Energy (keV) SHE Workshop - Paisley: 12th March 2008

  30. Conclusions Kp = 8- isomer with t1/2 = 109(6) ms observed in 252No Energy = 1.254 MeV. 2- and 8- energies are remarkably consistent across Z=94-102. Calculations with Woods-Saxon single particle energies reproduce trend in N=150 isotones as well as in 254No. ?..............¿ Evidence W.S potential no longer applicablefor Z=104 ? New Physics ! SHE Workshop - Paisley: 12th March 2008

  31. Collaboration A.P. Robinson, P. Marley University of York, UK T.L. Khoo, D. Seweryniak, S. Gros, I. Ahmad, B.B. Back, M. P. Carpenter, C.N. Davis, J. Greene, F.G. Kondev, T. Lauritsen, C.J. Lister, D. Peterson and S.ZhuArgonne National Laboratory, USA S.K. Tandel, P. Chowdhury, U. TandelUniversity of Massachusetts, Lowell, USA P.T. Greenlees, S. Eeckhaudt, R. Julin, M. Leino, J. Uusitalo University of Jyväskylä, Finland P.A. Butler, R.-D Herzberg, G. JonesUniversity of Liverpool, UK M. AsaiJapan Atomic Energy Agency (JAEA) A. Heinz, J. QianYale University, USA X. WangUniversity of Notre Dame, USA P. ReiterUniversität zu Köln, Germany SHE Workshop - Paisley: 12th March 2008

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