On-line nuclear orientation. Progress report, April 1, 1992--December 31, 1993

Abstract

This report describes progress made during the extended final year (April 1, 1992 to December 31, 1993) and summarizes the accomplishments of the entire three-year period (April 1, 1990 through December 31, 1993) of the current US Department of Energy grant DE-FG06-87ER40345. This work is carried out primarily at the UNISOR (University Isotope Separator at Oak Ridge) facility of the Holifield Heavy-Ion Research Facility of the Oak Ridge National Laboratory. The primary mission of this work is the study of the structure and properties of nuclei far from stability through on-line nuclear orientation using the UNISOR Nuclear Orientation Facility, a helium dilution refrigerator coupled on-line to the UNISOR mass separator. The author`s group was one of the original proposers of this facility and played a central role in its design, construction, and development. The structure of nuclei far from stability is in general poorly known. Knowledge from heavy-ion reactions is generally limited to states on or near the yrast line, and thus a great deal of the low-energy structure, especially that at low spin, is often missed in such studies. The large beta-decay energies, on the other hand, result in the population of a multitude of states which often givemore » a reasonably complete picture of the complex structure of these nuclei. The goal of this work is to use the nuclear orientation facility in conjunction with other UNISOR capabilities to examine and to understand the structure of these nuclei.« less