Decay of the high-spin isomers in /sup 150,151,152/Ho

The electron-capture decay properties of the high-spin isomers in /sup 150,151,152/Ho were investigated. The nuclides were produced in 10B bombardments of samarium and then transported to shielded areas with the use of gas-jet systems. Singles and coincidence γ-ray measurements were made. Each isomer decays primarily to one excited state in its dysprosium daughter by means of an allowed β transition (logft values are approx. 4.5). The following explanations are proposed. For 150Ho and 152Ho the transitions connect 9+(πh/sub 11/2/,νf/sub 7/2/) levels with 8+(νh/sub 9/2/,νf/sub 7/2/) levels in 150Dy(2401.8 keV) and 152Dy(2437.6 keV). Deexcitation to the ground states then follows via a cascade of four E2 γ rays. In 151Ho the β transition represents the changeover of an h/sub 11/2/ proton orbital to an h/sub 9/2/ neutron orbital in 151Dy. This single neutron state lies at 527.4 keV and deexcites directly to the ground state. The α decay of 152Ho was also investigated with the use of an on-line isotope separator. Its α-decay branching ratio was determined to be 10.5 +- 3.0%