(n, p) Reaction for Gold

Abstract

The paper reports an experimental study of the process ${\mathrm{Au}}^{197}(n, p){\mathrm{Pt}}^{197}$ induced by 14-Mev neutrons, detecting protons in the angular range 10° to 45° with emulsions. Resolution is not adequate for the identification of single excited states, but the energy spectrum does display definite structure and five groups are distinguished, chiefly on the basis of gross differences in their angular distributions. The energy widths of these groups are smaller than expected in view of the target thickness. Positions of angular distribution peaks are utilized for the assignment of angular momentum changes. The corresponding excitations in ${\mathrm{Pt}}^{197}$, with "final angular momentum" parameters and total cross sections, are: 0.2 Mev, 2, 8.6 mb; 1.6 Mev, 0 (or 4), 2.2 mb; 2.9 Mev, 5, 2.0 mb; 4.4 Mev, 6, 5.2 mb; 6.0 Mev, 4 (or 0), 2.5 mb. The sum of these cross sections (20.5 mb) is the experimental value for the reaction cross section, since the ground state transition was probably not observed (cross section estimated not over 0.6 mb) and no significant yield of protons was observed corresponding to Pt excitation between the highest listed and the maximum (13 Mev) represented in the spectrum. All cross sections are subject to about 40% uncertainty in neutron flux, but statistical uncertainties are of order 20% or less. Maximum differential cross sections for the groups, and their locations in the angular distributions, are tabulated.