LEVEL STRUCTURE AND REFLECTION ASYMMETRY IN TH-227

The level structure of Th227 has been studied using the electron capture decay of Pa227 and the β- decay of Ac227 to give a total of 20 levels where only four were previously known. This level structure then makes possible a more complete interpretation of the recently studied U231 alpha decay into Th227. The level structure can be interpreted using both strong coupling and intermediate coupling models in terms of K=1/2±,K=3/2±, and more tentative K=5/2± parity double bands which implies that Th227 has reflection asymmetry. Futhermore, the detailed interpretation of the level structure of Th227 solves the long standing problem of the ground state spin-parity of Th227 which is shown to be 1/2+. © 1995 The American Physical Society.