BETA–GAMMA ANGULAR CORRELATION IN 74As

Abstract

The A₂ coefficient of the beta–gamma angular correlation for the cascade 2⁻(β⁺)2⁺(γ)0⁺ in the positron decay of ⁷⁴As to ⁷⁴Ge has been measured as a function of energy. The values found are 0.015 ± 0.006 at W = 1.8, 0.019 ± 0.004 at W = 2.0, 0.030 ± 0.005 at W = 2.1, and 0.025 ± 0.005 at W = 2.2, where the energy W is measured in mc² units. The data have been used to examine the structure of the first excited level in ⁷⁴Ge, using the "modified B_ij approximation". Four shell-model configurations, as well as a rotational excitation, have been found to fit the experimental data. The validity of the application of the "modified B_ij approximation" to this decay is discussed.