In-beam spectroscopy study of the proton emitter {sup 151}Lu

Gamma rays decaying from the excited states of the proton-unbound {sup 151}Lu were observed for the first time in an experiment using the {sup 96}Ru({sup 58}Ni,thinspp2n){sup 151}Lu reaction. These {gamma} rays were identified by correlating prompt {gamma} radiations at the target position with {sup 151}Lu proton radioactivities at the focal plane of a recoil mass separator. Systematic data on N=80 isotones suggest a possible isomeric level at high spin in {sup 151}Lu. Our measurement was unable to observe such an isomer, but provided an upper limit on its half-life. The observed {gamma} rays in {sup 151}Lu can be interpreted in terms of two possible level structures. {copyright} {ital 1998} {ital The American Physical Society}