The isomeric cross-section ratio has been measured for the Br79(n, γ)Br80, 80m reaction and the results have been compared with the values predicted by the method of Huizenga and Vandenbosch. It can be inferred from the measured values that the average number of steps in the γ-cascades varies with the exciting energies. The value of σ ≈ 4 obtained for the spin density parameter in the investigated energy range of 0-3 MeV is in good agreement with those computed from the Fermi-gas model. The ratio of the effective to the rigid body moment of inertia was estimated to be about 0.8. It seems from the comparison of the measured and calculated cross-section ratios that thermal neutron capture occurs into the I+ 1 2 state.
- Nuclear Reactions