RADIOCHEMICAL MEASUREMENT OF EXCITATION-FUNCTION OF CU-63(N,P)NI-63 REACTION FROM 7.2 TO 14.6 MEV

Cross sections were measured for the formation of long-lived Ni-63 (T- 1/2 = 100 a) in (n,p) reaction on Cu-63 over the neutron energy range of 7.2 to 14.6 MeV. Radiochemical methods were developed to separate t he product Ni-63 from the bulk of copper and other radiocontaminants, and to prepare a thin source for soft beta(-) counting using a low-lev el anticoincidence detector. The experimental results are compared wit h the cross section values obtained via an integration of the emitted proton spectra. For estimating the Ni-63 activity, only the activation data are of relevance. The present data are also compared with severa l evaluations, all performed using the statistical model but with diff erent input parameters. The nuclear model calculations predict the exc itation functions of (n, charged particle) reactions only with moderat e accuracy. For reactions of high importance, accurate radiochemical m easurements appear to be mandatory.