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The radiation from Ho153 has been measured with Compton-suppressed Ge detectors. At least four components can be identified; the energy and spin removed by each of these have been measured, and their Doppler shifts analyzed. New fine structure is observed in the pre-yrast spectrum which arises from single-particle transitions forming the link between the yrast and continuum cascades. Near the yrast line the single-particle character of the states is preserved, but at higher energies collective modes begin to dominate.

The level structure of the four-valence-proton N=82 nucleus Er150 has been studied by -ray spectroscopy following reactions of 225-255 MeV Ni58,60 beams on Mo92,94,95 and Nb93 targets. Yrast levels in Er150 are established up to 9.5 MeV excitation energy; they include isomeric levels at 2797, 7372, and 9509 keV. The observed levels up to 5222 keV are interpreted in terms of shell model configurations involving the four valence protons outside the Gd146 core. They include states with dominant seniority two and four configurations h1124, h1123s12, and h1123d32, and octupole excitations. The levels above 5222 keV must involve excitation of the Gd146 core, and they are not interpreted in detail. The energies of the h1124 levels are found to agree reasonably with predictions based on empirical two-body interactions taken from the h1122 spectrum of Dy148. Even better agreement is obtained by taking account also of the known h1123 energies in Ho149. The dependence of E2 transition probabilities in N=82 nuclei on the h112 subshell occupation number is discussed.