A. A. Hecht

High spin states of 135Pr

The mass A = 130 region has been of particular interest both theoretically and experimentally as nuclei in this region are expected to exhibit soft behaviour related to the shape asymmetry parameter γ. The level scheme has been extended considerably up to spin 83/2− with a further possible transition to spin 85/2−.

The Highs And Lows Of The A=100 Region: Vibration-To-Rotation Evolution In Mo And Ru Isotopes

Nuclei below the Z = 50 magic shell gap with A∼100 show a wide variety of structural phenomena. These include excellent examples of vibrational collectivity at low-spins, which give way to more rotational-like excitations with increasing angular momentum. In this paper we present recent results from an experiment performed at Yale to study the yrast evolution of states in 98,99 Mo and 101,102 Ru. Although the high-spin data is consistent with predictions from rotational model theories, we propose a simple presciption to distinguish between vibrational and rotational regimes of angular momentum generation. When applied to the nuclei of interest, a clear picture emerges of how these two mechanisms of collective spin generation compete in this region.

SASSYER: A Gas‐filled spectrometer at Yale

The Wright Nuclear Structure Laboratory has recently acquired a gas‐filled recoil separator previously used at Berkeley National Laboratory for heavy‐element synthesis. The separator will be used to separate reaction recoils from primary beam particles and fission products following target bombardment. Commisioning of the separator has recently been completed, and the structure of 203Rn investigated.