Level sructure in ²⁰⁶At

Abstract:

The high-spin states of ²⁰⁶At have been studied in the reaction ¹⁹⁷Au (¹²C,3n) ²⁰⁶At at ¹²C energies from 60 to 80 MeV. In-beam measurements of γ-ray excitation functions, γ-γ-t coincidences, and γ-ray angular distributions were carried out with seven BGO(AC)HPGe detectors and one intrinsic Ge planar detector. A level scheme for ²⁰⁶At with 25 γ rays was established for the first time, including a 10⁻ isomer with a measured half-life of 410 ± 80 ns. The level scheme of ²⁰⁶At consists of two disconnected cascades, probably corresponding to the proton excitations and the neutron-hole excitations, respectively.