Range of 2- to 60-Kev Recoil Atoms in Cu, Ag, and Au

The ranges of atoms recoiling from photoneutron reactions in Cu, Ag, and Au have been measured utilizing foil-sandwich irradiations followed by standard radiochemical detection techniques. Different energy spectra of recoil atoms were achieved by varying the bremsstrahlung energy and the angle of emission relative to the incident photons. The results have been compared with calculations of Holmes and Leibfried. The best fit to the data is achieved by assigning values of the multiplicative parameter of the screening radius, $\alpha$, equal to 1.7 for Cu, 2.0 for Ag, and 3.0 for Au.