Prompt and delayed spectroscopy of at 203: Observation of a shears band and a 29/2+ isomeric state

Abstract

Using fusion-evaporation reactions, a gas-filled recoil separator, recoil-gating technique and recoil-isomer decay tagging technique we have extended the level scheme of At203(N=118) significantly. We have observed an isomeric [τ=14.1(3)μs] state with a spin and parity of 29/2+. The isomeric state is suggested to originate from the π(h9/2) - |Po202;11-) coupling, and it is depopulated through 286 keV E2 and 366 keV E3 transitions. In addition, we have observed a cascade of magnetic-dipole transitions which is suggested to be generated by the shears mechanism.