Determination of the fission averaged cross sections of some threshold reactions induced on chlorine, potassium, and calcium, and their role in the development of self-validated methods of neutron activation analysis

The feasibility of validating data obtained in the determination of chlorin e, potassium, and calcium by neutron capture activation analysis, through t heir determination using threshold reactions has been studied. To this purp ose the authors experimentally determined the following fission neutron spe ctrum averaged cross sections (in mb): Cl-37(n, p)S-37, 0.234 +/- 0.015; K- 41(n, alpha)Cl-38, 0.740 +/- 0.044; Ca-42(n, p)K-42, 3.09 +/- 0.22; Ca-43(n , p)K-43. 2.27 +/- 0.12; Ca-44(n, p)K-44, 0.074 +/- 0.013. The application of these values to the analysis of some reference materials are presented. Also, the problem of mutual interferences has been addressed for the follow ing pairs: S-36(n,gamma)S-37 andd Cl-37(n, p)S-37; Cl-37(n, gamma)Cl-38 and K-41(n, alpha)Cl-38; K-41(n, gamma)K-42 and Ca-42(n, p)K-42.