Gamma Rays from Thermal Neutron Capture in Cl, V, Mn, and Co

Abstract

The high-energy $\gamma$ rays ($E_{\gamma }>5\mathrm{}$ MeV) emitted in thermal-neutron capture by Cl, V, Mn, and Co have been observed with 20-keV resolution using a single lithium-drifted germanium detector and paraffin-moderated Pu-Be neutrons. The previously reported ground-state $\gamma$ rays in Mn and V are found to contain primary transitions to the first excited states near 20-keV excitation. In addition, previously unreported lines in all four elements have been observed; most of these have been identified as primary transitions to levels known from ($d, p$) studies. Little correlation between the reduced $\gamma$-ray strengths $\frac{I_{\gamma }}{{E_{\gamma }}^3}$ from the ($n, \gamma$) reaction, and the relative transition strengths $\mathrm{}(2J+1)S$ from the ($d, p$) reaction, is observed in Co and V.