Average magnetic moments of pre-yrast high spin states in 166,165Hf.

Abstract

The average magnetic moments of high spin states in Hf isotopes were determined in a transient field measurement at the 14 MV Koffler accelerator of the Weizmann Institute. The reaction $^{130}\mathrm{Te}$${(}^{40}$Ca,xn${)}^{166,165}$Hf at beam energies from 167 to 182.5 MeV was used to populate different high spin regions and provide the recoiling Hf nuclei with sufficient velocity to traverse the 2.9 mg/${\mathrm{cm}}^{2}$ Gd ferromagnetic layer. Standard double ratios and angular distributions for various low level transitions were measured to determine precession angles. These carry information regarding the average g factor of unobservable transitions at medium excitation. To obtain a more quantitative analysis regarding the time-decay history of the \ensuremath{\gamma} cascade, Monte Carlo simulations of the cascade were carried out. The significance of the results for understanding the single particle nature of these pre-yrast levels is discussed. \textcopyright{} 1996 The American Physical Society.