Recoil Range Distributions as Probes of Compound-Nucleus Reactions

Abstract

The electrostatic collection of Dy ions recoiling in ${\mathrm{H}}_2$ gas has been examined. Range distributions for ${\mathrm{Tb}}^{149g}$ production from Tb compound systems [(H.I., $\mathrm{xn}$) reactions] have been measured. These range distributions, along with angular distributions measured formerly, indicate essentially isotropic neutron emission. Range distributions have been obtained for collimated recoils from the reaction ${\mathrm{Nd}}^{144}({\mathrm{C}}^{12}, 7n){\mathrm{Dy}}^{149}$. The data are consistent with a Maxwellian distribution of recoil speeds in the c.m. system.