High-spin yrast structure of 159Ho

An investigation of the yrast structure of the odd-Z Ho-159 nucleus to high spin has been performed. The Ho-159 nucleus was populated by the reaction Cd-116(Ca-48, p4n gamma) at a beam energy of 215 MeV, and resulting gamma decays were detected by the Gammasphere spectrometer. The h(11/2) yrast band has been significantly extended up to I-pi = 75/2(-)( tentatively 79/2(-)). A lower frequency limit for the second (h(11/2))(2) proton alignment was extracted consistent with the systematics of this alignment frequency, indicating an increased deformation with neutron number in the Ho isotopes. The energy-level splitting between the signature partners in the h11/2 structures of the Ho isotopes and the neighboring N = 92 isotones is discussed.