Systematics of high-spin isomers in N = 83 isotones and a high-spin isomer beam

Abstract:

Isomers in N = 83 isotones of Z = 60-66, were studied systematically. Their spins and parities are 49/2⁺ and 27⁺ for odd and odd-odd nuclei, respectively. Nearly constant excitation energies of these isomers indicated a decrease of a Z = 64 shell gap energy as Z decreases from 64 to 60 within the framework of a deformed independent-particle model (DIPM). Their configurations are [ν(f _7/2 h _9/2 i _13/2),π(h _11/2)²]_49/2+ and [ν(f _7/2 h _9/2 i _13/2),π(h _11/2)²(d _5/2)^-1]₂₇₊ for odd and odd-odd nuclei, respectively. The shape of the yrast states changes suddenly at spin 49/2(odd) and 27(odd-odd) from a near spherical to an oblate shape. Transitions from isomers are highly hindered because of the shape changes. They may be categorized to be shape isomers. The development of a secondary beam produced by using these high-spin isomers is also described.