Observation of M3 Isomeric Transition from 156m Pm Through the Βdecay of 156 Nd

An M3 transition in a doubly odd nucleus of 156Pm was identified by internal conversion electron measurement through the β-decay of 156Nd which was separated from the fission products of 235U using the on-line mass separator KUR-ISOL. The isomeric state at 150.3keV de-excites to the ground state with the M3 transition, and the spin-parity is considered to be 1-. Nilsson configurations are also discussed on the basis of the systematics.