[en] Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI = 4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well

[en] 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; (1) N-Z nuclei at the edges of stability, (2) the properties of excited states in proton emitters, and (3) the stability and shapes of very heavy nuclei will be presented

[en] The coupling of a Compton-suppressed Ge (CSGe) detector array to a recoil separator has seen limited use in the past due to the low efficiency for measuring recoil--γ ray coincidences (< 0.1%). With the building of new generation recoil separators and gamma-ray arrays, a substantial increase in detection efficiency has been achieved. This allows for the opportunity to measure excited states in nuclei with cross-sections below 100 nb. In this paper, results from the coupling of a modest array of CSGe detectors (AYE-Ball) and a current generation Ge array (Gammasphere) with a recoil separator (FMA) will be presented

[en] A major program of Gammasphere when coupled with the Fragment Mass Analyzer (FMA) has been to study excited states in nuclei beyond the proton drip line. We have recently performed in-beam experiments using Gammasphere + FMA to measure excited states in proton rich Au, Hg, Tl and Pb isotopes. These studies have allowed us to characterize the evolution of nuclear shapes as one approaches the proton drip line. In two of the isotopes studied, namely 175Au and 179Hg, structures built on three distinct shapes have been found to coexist at low excitation energy

[en] Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI=4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well

No abstract available

[en] A γ -ray spectroscopic measurement of the N=Z nucleus ⁶⁸Se has been made following the ¹²C( ⁵⁸Ni, 2 n) reaction at 185 and 220 MeV using Gammasphere and the Argonne Fragment Mass Analyzer. Despite a very low production cross section of 200(50) μb , two distinct rotational bands were found; the ground state band consistent with oblate collective rotation, and an excited band consistent with prolate rotation. These observations support long-standing predictions that nuclear ground states with substantial oblate (β₂∼-0.3) deformation should exist in this region. (c) 2000 The American Physical Society

No abstract available

[en] Superdeformation has been established for over a decade in the mass 150 region and nearly as long in the A=190 region. The first measurements directed at nuclei in these regions concentrated on mapping out the superdeformed (SD) islands by identifying SD rotational bands in γ-ray coincidence data. These early studies provided new insights into the physics of superdeformation, but also raised unexpected issues. The new gamma-ray arrays (Gammasphere, Eurogam/Euroball and Gasp) have provided a wealth of new data on properties of SD states in these two mass regions. This paper highlights some of the more recent results from the large arrays which have addressed the outstanding issues in the field, namely, ΔI=4 staggering, identical bands, SD vibrational bands, and questions about the feeding into and the decay out of the SD well. (c) 1999 American Institute of Physics

[en] In a recent experiment to study the proton radioactivity of the highly deformed ¹³¹Eu nucleus, two proton lines were detected. The higher energy one was assigned to the ground-state to ground-state decay, while the lower energy, to the ground-state to the 2⁺ state decay. This constitutes the first observation of fine structure in proton radioactivity. With these four measured quantities, proton energies, half-life and branching ratio, it is possible to determine the Nilsson configuration of the ground state of the proton emitting nucleus as well as the 2⁺ energy and nuclear deformation of the daughter nucleus. These results will be presented and discussed