Partial neutron cross sections for 39K and 41K between 14.4 and 18.2 MeV

Abstract

Activation techniques have been used to measure the cross sections for the 39K(n, 2n) 38gK reaction at neutron energies between 14.4 and 18.2 MeV, the cross sections for the 41K(n, α) 38Cl reaction from 14.4 to 16.3 MeV and the cross sections for the 41K(n, p) 41Ar reaction from 14.4 to 17.3 MeV. Gamma-rays from the decay of the residual nuclei were detected with an HPGe detector whose energy resolution at 1.33 MeV is approximately 1 keV fwhm. The mixed powder method was employed to determine the neutron flux at each neutron energy, and the associated particle method was used to check the mixed powder flux measurements at 14.4 and 15.4 MeV. Good agreement was obtained for the average cross sections computed using both methods. Measured cross sections for the 39K(n, 2n) 38gK reaction are 2.2 ± 0.2, 5.8 ± 0.4, 6.6 ± 0.5, 14.4 ± 0.9 and 22.1 ± 1.5 mb at 14.4 ± 0.2, 15.4 ± 16.3 ± 0.1, 17.3 ± 0.1 and 18.2 ± 0.1 MeV, respectively. Cross sections for the 41K(n, p) 41Ar reaction are 52.9 ± 2.6, 44.9 ± 2.1, 41 and 34.2 ± 3.0 mb, respectively for the first four neutron energies listed above, and, for the first three energies, the cross sections for the 41K(n, α) 38Cl reaction are 34.4 ± 2.4, 28.5 ± 2.2 and 24.5 ± 2.6 mb.