How far from stability can we go using Gammasphere and the ANL Fragment Mass Analyzer?

Abstract

Gammasphere is the pre-eminent detector for gamma-ray spectroscopy studies in the United States. The device consists of up to 110 Compton-Suppressed Ge detectors, and offers excellent energy resolution (2.3 keV at 1 MeV) and an order of magnitude increase in photopeak efficiency over previous Ge-arrays (10% at 1 MeV). Since early January 1998, Gammasphere has begun a cycle of experiments at the ATLAS accelerator at Argonne National Laboratory. As of this writing, 100 experiments have been carried out. A subset of these experiments have utilized Gammasphere coupled to the Fragment Mass Analyzer (FMA), a high resolution mass spectrometer which transports reaction products produced at the target position and disperses them by their mass/charge ratio at the focal plane. This presentation will highlight some of the physics issues being addressed by the utilization of these two devices in tandem. More specifically, experiments directed at studying (i) N=Z nuclei at the edges of stability, (ii) the properties of excited states in proton emitters (iii) the stability and shapes of very heavy nuclei will be presented.