Study of neutron induced charged particle reactions on ⁴⁰K. (II). Resonance neutrons

The ⁴⁰K(n, α)³⁷Cl and ⁴⁰K(n, p)⁴⁰Ar reaction cross sections were measured in the neutron energy region from 0.02 eV up to about 70 keV. The proton and α-particles were detected with a large surface barrier detector, and the neutron energy was measured by time of flight. The reaction cross sections show a pronounced resonance structure. A comparison of the density of s- and p-wave resonances (compound spins between 5 2 and 11 2 in ⁴⁰K + n to the density of spin - 5 2 compound states observed as resonances in the reaction ⁴⁰Ar + p by Keyworth et al., allows a direct determination of the spin cut-off parameter of the level density.