Cross-section measurements of the 81Br(n,2n)80mBr reaction via secondary nuclear decay

The secondary nuclear decay method was applied for the cross-section measurement of the 81 Br(n,2n) 80m Br reaction. As a result, the cross-sections of the 81 Br(n,2n) 80m,g Br reactions with a detailed uncertainty propagation and their isomeric cross-section ratios σ m /σ g were obtained at four neutron energies within the range from 13 to 15 MeV by applying an activation and off-line γ-ray spectrometric technique. The Br-based samples and Nb-based monitor foils were activated together to determine both the reaction cross-sections and the incident neutron flux . The neutron beam was formed via the 3 H( d , n ) 4 He reaction. The cross-sections were also calculated by using a theoretical nuclear model code TALYS-1.95 with different options of level density at neutron energies varying from the reaction threshold to 20 MeV. The extracted results were analytically discussed and compared with the corresponding theoretical and evaluated data from the published works in the literature.