Inelastic excitation of new high-spin yrast isomers in ¹⁸⁰Ta

For the first time, six-quasiparticle isomers have been observed in the meta-stable nucleus ₇₃¹⁸⁰Ta₁₀₇. Two new high-spin isomers were populated following deep-inelastic reactions with a pulsed ₉₂²³⁸U beam incident on a thick ₇₂¹⁸⁰Hf target. Out-of-beam γ-ray events were collected using the Gammasphere germanium detector array. In addition to the known four-quasiparticle isomers, yrast K^π=(22^-) and K>~23 six-quasiparticle isomers have been observed with microsecond half-lives. These are the highest-spin isomers observed using the technique of deep-inelastic excitation. The assignments are compared to predictions made by BCS and Lipkin-Nogami multiquasiparticle calculations.