Level structure of 75Se by the 75As(p,nγ)75Se reaction

Excitation functions of γ-rays from the ⁷⁵As(p, n)⁷⁵Se reaction were measured with 2.0 to 3.6 MeV protons to establish the level scheme of ⁷⁵Se up to about 1.5 MeV excitation energy. Internal conversion electrons following the same reaction were measured at 4.5 and 5.0 MeV proton energy. Using theoretical predictions of the statistical compound nucleus model together with deduced internal conversion coefficients, unique spin assignments were obtained for the $\text{112.5(}\text{7}\text{2}{}^{\mathrm{+}}\text{), 427.9(}\text{5}\text{2}{}^{\mathrm{?}}\text{)}$ and $\text{663.9(}\text{5}\text{2}{}^{\mathrm{?}}\text{)}\text{keV}$ levels. Probable spins were proposed to the $\text{286.6 (}\text{3}\text{2}{}^{\mathrm{?}}$ for one of the doublet and $\text{5}\text{2}{}^{\mathrm{?}}$ or $\text{7}\text{2}{}^{\mathrm{?}}$ for the other), 579.4 $\text{(}\text{1}\text{2}{}^{\mathrm{?}}$ or $\text{3}\text{2}{}^{\mathrm{?}}$, $\text{585.8(}\text{9}\text{2}{}^{\mathrm{?}}$ or $\text{11}\text{2}{}^{\mathrm{?}}$ and $\text{747.6 (}\text{5}\text{2}{}^{\mathrm{?}}$ or $\text{7}\text{2}{}^{\mathrm{?}}\text{)}\text{keV}$ levels. Alow-lying $\text{9}\text{2}{}^{\mathrm{+}}$ level was tentatively assigned at 133.2 keV energy. It was found that a low-lying $\text{1}\text{2}{}^{\mathrm{?}}$ level which appears systematically in other odd Se nuclei is absent in ⁷⁵Se.