Session FR: CEU Poster Session

1:00 PM–1:00 PM, Wednesday, September 21, 2005
Ritz-Carlton Hotel - Ballroom Foyer 1:00pm - 3:00pm

Sponsoring Units: DNP JPS

Abstract: FR.00047 : The Time of Flight Technique for Nuclear Lifetime Measurements

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Authors:

  Aaron Chester
  Ryan Mckendree
    (Michigan State University)

  Krzysztof Starosta
  Wilhelm Mueller
  Ana Becerril
  Heather Olliver
  Russ Terry
  Chris Campbell
  Jon Cook
  Cristian Dinca
    (NSCL)

The onset of deformation in even-even nuclei is known to be manifested by a decreasing energy of the 2$^{+}$ excited state, E (2$^{+}$), correlated with an increase in the associated reduced transition probability B(E2). It is surprising to observe for A$\ge^{110}$Pd nuclei that as E(2$^{+}$) decreases, so does B (E2). It is proposed to reinvestigate this trend using the time of flight technique, which is undergoing development at the NSCL. With this method, a fast beam of degraded nuclei of interest produced in a fragmentation reaction is Coulomb excited to the 2$^{+}$ state on a moveable target. A stationary degrader is positioned downstream to further slow the nuclei. Gamma-rays emitted during the de-excitation process before and after the degrader are measured at a different Doppler shift. The SeGA array of segmented germanium detectors is used for gamma-ray detection as it provides an optimal balance of sensitivity to changes in velocity and energy resolution. The ratio of intensities of the measured peaks yields information about the lifetime at the measured velocity. The results of a proof of principle experiment performed with the primary beam of $^{124} $Xe will be presented.