Gamma-gamma and electron-gamma angular correlation studies in the decay of 75Se

Abstract

The multipolarities of the 121 keV, 136 keV, 265 keV and 280 keV transitions in the decay of 75Se have been determined from γγ and e −γ angular correlation measurements. The use of a Ge(Li) detector gave a complete separation of the different γ-lines. Consequently, more reliable results could be obtained than previous NaI(Tl) measurements had given. We derive from the new data of the γγ angular correlation experiments for the 265 keV and 280 keV lines the mixing parameters σ(265 keV)=−0.0425 ±0.0064, σ(280 keV)=−0.0480±0.026 . The e −γ angular correlation measurements have been performed using a Si(Li) detector as well as a magnetic-lens spectrometer for the detection of the conversion electrons. From these experiments, we obtain for the 121 keV and 136 keV transitions, the K-shell particle parameters b 2(121 keV)=−1.91±0.04, b 2(136 keV)=−1.85 ±0.16 . These values are in good agreement with the particle parameters for E1 multipolarity calculated by Biedenharn and Rose.