Investigations of the ReactionCl35(n, γγ′)Cl36

Abstract

Two-step gamma-ray cascades to the ground state of ${\mathrm{Cl}}^{36}$ following thermal neutron capture by ${\mathrm{Cl}}^{35}$ have been investigated with the sum-coincidence apparatus. The direct experimental result is the product $I_1{b}_2$ of the intensity $I_1$ of the initial transition and the branching factor $b_2$ of the intermediate state to the ground state. The quantity $b_2$ is separately deduced from auxiliary information about $I_1$. The lower-energy members of the stronger cascades occur at 0.79, 1.16, 1.60, 1.96, and 2.87 Mev with respective values of $I_1{b}_2$ of 8.2, 11.6, 2.9, 12.1, and 5.1 per 100 neutrons captured. Weaker cascades appear at 2.2, 2.48, 2.6, 2.68, and 3.05 Mev. Cascades appearing between 3.3 and 4.3 Mev have $I_1{b}_2⋜0.5\%$. The $b_2$ following the strongest of all initial transitions, viz., 6.11 Mev, is only ⋜ 0.02. Approximately 46% of all neutrons captured produce two-step cascades in ${\mathrm{Cl}}^{36}$.