Session GC: Nuclear Structure IV

9:00 AM–11:48 AM, Saturday, October 28, 2006
Gaylord Opryland - Tennessee B

Sponsoring Unit: DNP
Chair: Jolie Cizewski, Rutgers University

Abstract: GC.00003 : Four-, Six- and Eight-quasiparticle Isomers in $^{174}$Lu

9:24 AM–9:36 AM

Preview Abstract

Authors:

  F.G. Kondev
  I. Ahmad
  M.P. Carpenter
  R.V.F. Janssens
  T. Lauritsen
  C.J. Lister
  D. Seweryniak
    (Argonne National Laboratory)

  G.D. Dracoulis
  G.J. Lane
  A.P. Byrne
  T. Kibedi
    (Australian National University)

  P. Chowdhury
  S.K. Tandel
    (University of Massachusetts Lowell)

We report on new studies of $^{174}$Lu using a $^{136}$Xe beam from the ATLAS accelerator at Argonne National Laboratory that was incident on targets of natural Lu and enriched (to 47\%) $^ {176}$Lu. The targets were 6 mg/cm$^{2}$ in thickness with 25 mg/cm$^{2}$ of Au backing. The beam was pulsed approximately 1 ns on/825 ns off at energies of 6 MeV per nucleon. The recoils were stopped at the target position in the focus of the Gammasphere spectrometer, comprised for this experiment of 96 Compton-suppressed Ge detectors. Several high-K isomers were discovered in $^{174}$Lu and their structure characterized, including K$^{\pi}$=13$^{+}$ ($\tau$=280 (25) ns), 14$^{-}$ ($\tau$=55 (6) ns), (21$^{+}$) ($\tau$=140 (15) ns) and (26$^{-} $) ($\tau$=350 (28) ns). The 13$^{+}$ isomer was found to decay to both low-K (K$^{\pi}$=0$^{+}$) and high-K (K$^{\pi}$=7$^{+} $) states originating from couplings of the $\pi$ $7/2[404]$ and $\nu$ $7/2[633]$ orbitals. The path via the K$^{\pi}$=0$^{+} $ band cannot be explained through conventional Coriolis mixings and the accidental mixing scenario between the isomer and a nearby collective level was invoked [1]. Details of these measurements will be presented, together with a comparison with predictions from multi-quasiparticle calculations. \\ $[1]$ G.D. Dracoulis et al., submitted to Phys. Rev. Lett. \\