Study of Some (p, n) Reactions by Neutron Time of Flight

Abstract

A millimicrosecond time-of-flight technique has been applied to the study of ($p, n$) reactions in K, ${\mathrm{Ca}}^{48}$, Ti, Cr, Mn, Fe, Cu, As, and Rb using the phase-focused 3-Mev proton beam from a small fixed-frequency cyclotron. The neutron spectra, resulting from these reactions, gave data from which the ground-state $Q$ values and some of the energy levels in the residual nuclei have been determined. The reactions in K and Fe yielded only one neutron group each, which corresponded to the ground states in ${\mathrm{Ca}}^{41}$ and ${\mathrm{Co}}^{57}$, respectively. In addition to the ground state $Q$ values, the energies were determined for one excited state in each of the nuclei ${\mathrm{Mn}}^{53}$, ${\mathrm{Mn}}^{54}$, and ${\mathrm{Sr}}^{85}$, two excited states in ${\mathrm{Zn}}^{65}$, three excited states in ${\mathrm{Sr}}^{87}$, and four excited states in each of the nuclei ${\mathrm{Sc}}^{48}$, ${\mathrm{V}}^{49}$, ${\mathrm{Fe}}^{55}$, and ${\mathrm{Se}}^{75}$. The angular distributions of the neutron groups were observed to be essentially isotropic in the ${\mathrm{Ca}}^{48}(p, n){\mathrm{Sc}}^{48}$ and ${\mathrm{Cu}}^{65}(p, n){\mathrm{Zn}}^{65}$ reactions.