HIGH-SPIN STATES OF ODD-ODD HO-156

Abstract

High spin states in the nucleus Ho-156 have been studied via the fusion-evaporation reaction Ce-140(F-19,3n gamma)Ho-156 at the beam energy of 82 MeV. gamma-gamma coincidences, E(gamma), I-gamma and excitation functions have been measured. With two rotationally-aligned bands identified as pi[h(11/2)]nu [i(13/2)], we found two new bands with a signature splitting, whose structure is believed to arise from either nu[h(9/2)] or nu[f(7/2)] coupled to pi[h(11/2)]. Our placement of gamma rays belonging to these new bands suggests that the previously known level scheme should be corrected. We also found many new low-energy gamma rays in the low excitation energy. As compared to Ho-154, the present nucleus with two more neutrons becomes more collective, and shows well-observed rotationally-aligned bands with a clear signature splitting.