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The reaction of a pulsed 18O beam on a 164Dy target was studied in the first experiment with the NuBall array at the IPN Orsay, France. Excited state half-lives were measured using the fast timing method with 20 LaBr3(Ce) detectors. The timing characteristics of the fully digital acquisition system is briefly discussed. A value for the previously unknown half-life of the first excited 4+ state in 178W is presented. [ABSTRACT FROM AUTHOR]

We report on the first measurement of the half-lives of K π = 11 − and 12 + four-quasiparticle states in the even-even nucleus 178W. The sub-nanosecond half-lives were measured by applying the centroid shift method to data taken with LaBr 3 (Ce) scintillator detectors of the NuBall array at the ALTO facility in Orsay, France. The half-lives of these states only became experimentally accessible by the combination of several experimental techniques - scintillator fast timing, isomer spectroscopy with a pulsed beam, and the event-by-event calorimetry information provided by the NuBall array. The measured half-lives are 476 (44) ps and 275 (65) ps for the I π = 11 − and 12 + states, respectively. The decay transitions include weakly hindered E 1 and E 2 branches directly to the ground-state band, bypassing the two-quasiparticle states. This is the first such observation for an E 1 transition. The interpretation of the small hindrance hinges on mixing between the ground-state band and the t-band. [ABSTRACT FROM AUTHOR]