Some activation measurements with 3H(d,n)4He neutrons

Accuracy of the concentric ring geometry for fast neutron monitoring is verified by activating concentric rings and discs, which were made of copper, and measuring the neutron fluxes using the 63Cu(n,2n)62Cu reaction. Consistent results were obtained using 3H(d,n)4He neutrons from Van de Graaff and Dynamitron accelerators. In addition, 12.9-15.9 MeV neutrons were used to measure the excitation function for the 121Sb(n,2n)120sup(g)Sb reaction and the ratios of 63Cu(n,2n)62Cu and 27Al(n,p)27Mg reaction cross-sections, which were used for neutron energy determination. The investigation includes also a novel gamma ray counting method for the determination of the antimony cross-section, and recommendations for establishing the concentric ring technique as a standard. (orig.)