Energy Loss and Range of Fission Fragments in Solid Media

Abstract

Energy losses and ranges in Mylar have been measured for some representative fission fragments; these data and existing stopping-power measurements for bromine and iodine ions in media from carbon to gold are shown to be consistent with a semiempirical theory which treats electronic stopping processes in terms of an effective charge ${{Z}_{1}}^{*}$ which depends on the velocity of the ion. The fractional effective charge $\frac{{{Z}_{1}}^{*}}{{Z}_{1}}$ is shown to be a universal function of the variable $\frac{v}{{v}_{0}{{Z}_{1}}^{\frac{2}{3}}}$, where ${v}_{0}$ is the Bohr velocity and ${Z}_{1}$ is the nuclear charge of the fragment. This semiempirical treatment, when combined with existing theoretical estimates for nuclear stopping powers, correctly predicts ranges of fission-fragment-like ions.