In-Beam Spectroscopy of $^{215}$Ac

ORAL

Abstract

Knowledge of the evolution of proton single particle energies beyond the Z=82 shell closure is a vital ingredient in predictions of the stability of superheavy elements. In contrast to relativistic mean-field model predictions, which are used to describe shell stabilization effects, recent experiments have shown no indication of a subshell closure at Z=92. In-beam gamma spectroscopy of $^{215}$Ac has recently been carried out to study the evolution of structure of the N=126 isotones. Previous study of this isotope has been limited to delayed-gamma and alpha-gamma techniques. The powerful technique of recoil-decay-tagging using the gas-filled separator SASSYER and a newly commissioned focal plane detection system was implemented to extract decays associated with the weak fusion channel production of $^{215}$Ac. Experimental results will be presented and interpretation will be discussed in the framework of the shell model. This work is supported by U.S. DOE Grant No. DE-FG02-91ER-40609.

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Authors

  • R. Winkler

    • Yale University
    • WNSL Yale

  • A. Heinz

  • J. Qian

  • J.R. Terry

  • R.J. Casperson

  • R.F. Casten

  • A. Schmidt

  • V. Werner

  • E. Williams

    • Yale University

  • Z. Berant

    • Yale University, Nuclear Research Center Negev

  • M. Bunce

    • Yale University, University of Surrey

  • G. Henning

    • Yale University, ENS de Cachan