부산대학교 도서관

A newly observed isomeric intruder ½+ state [T ½ = 3.5(6) ms] is identified in 203At using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E3 and mixed M1/E2 transitions to the 9/2- ground state, and it is suggested to originate from the π(s½)-1 configuration. In addition, the structures above the ½+ state in 203At and 197At are studied using in-beam γ-ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The ½+ state is fed from 3/2+ and 5/2+ states, and the origin of these states are discussed. [ABSTRACT FROM AUTHOR]