Ranges and Stopping Cross Sections of Low-Energy Tritons

Abstract

Stopping cross sections and ranges of tritons as a function of energy from \ensuremath{\sim}0.2 to 2.7 MeV have been measured in polystyrene, nitrogen, air, aluminum, argon, nickel, krypton, and xenon by a conicidence technique utilizing the ${\mathrm{Li}}^{6}(n,\ensuremath{\alpha}){\mathrm{H}}^{3}$ reaction. The ranges found for 2.736-MeV tritons in these materials are 6.12\ifmmode\pm\else\textpm\fi{}0.10, 7.26\ifmmode\pm\else\textpm\fi{}0.06, 7.34\ifmmode\pm\else\textpm\fi{}0.06, 10.10\ifmmode\pm\else\textpm\fi{}0.10, 11.40\ifmmode\pm\else\textpm\fi{}0.09, 15.15\ifmmode\pm\else\textpm\fi{}0.15, 17.83\ifmmode\pm\else\textpm\fi{}0.18, and 20.36\ifmmode\pm\else\textpm\fi{}0.20 mg/${\mathrm{cm}}^{2}$, respectively. Above $\frac{{E}_{t}}{Z}\ensuremath{\approx}0.05$, the atomic stopping cross section $\ensuremath{\epsilon}$ in eV-${\mathrm{cm}}^{2}$ is given $\ensuremath{\epsilon}\ifmmode\times\else\texttimes\fi{}{10}^{15}=4{(\frac{{E}_{t}}{Z})}^{\ensuremath{-}\frac{1}{2}}\ensuremath{-}{(\frac{{E}_{t}}{Z})}^{\frac{1}{2}}$, where ${E}_{t}$ is the triton energy in MeV and $Z$ is the atomic number of the absorber. The data are compared with stopping theories for the velocity region in which shell effects cause deviations from the simple higher energy stopping theory.