Energy loss and straggling of 100-500-keVTh90,Pb82,Hg80, andGd64inH2

Energy-loss distributions of ${}_{90}{}^{}{}_{}{}^{}\mathrm{Th}$, ${}_{82}{}^{}{}_{}{}^{}\mathrm{Pb}$, ${}_{80}{}^{}{}_{}{}^{}\mathrm{Hg}$, and ${}_{64}{}^{}{}_{}{}^{}\mathrm{Gd}$ after passage through hydrogen are reported in the energy interval $100<E<\mathrm{}500\mathrm{}$ keV. The first three moments were extracted and compared with theoretical values of Lindhard et al. and reasonable agreement was obtained. Calculations of the energy-loss distributions were performed for the case where the projectiles lose their energy by elastic collisions with target atoms. Examples of calculated distributions are shown together with measured distributions.