The fast cyclic neutron activation technique at the Karlsruhe 3.75 MV Van de Graaff accelerator and the measurement of the 107,109Ag(n, γ) 108,110Ag cross sections at kT = 25 keV

Abstract

The neuton activation technique is studied for product nuclides with half-lives more than a year down to a few seconds. A new system for the measurement of Maxwellian averaged capture cross sections with this technique was developed especially for isotopes with induced activities with half-lives of only a few seconds. In order to collect sufficient capture events the two phases of an activation, irradiation and activity counting, are repeated periodically. This fast cyclic activation method is described and activation measurements on 107,109Ag are reported. The Maxwellian averaged capture cross sections of 107Ag, and 109Ag at kT = 25 keV were found to be 786 ± 60 mb and 887 ± 75 mb, respectively. The abilities of the activation method to measure cross sections of only a few μbarns are discussed.