Ranges and Stopping Cross Sections of Low-Energy Tritons

Stopping cross sections and ranges of tritons as a function of energy from ∼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 ${\mathrm{Li}}^6(n,\alpha ){\mathrm{H}}^3$ reaction. The ranges found for 2.736-MeV tritons in these materials are 6.12±0.10, 7.26±0.06, 7.34±0.06, 10.10±0.10, 11.40±0.09, 15.15±0.15, 17.83±0.18, and 20.36±0.20 mg/${\mathrm{cm}}^2$, respectively. Above $\frac{E_t}{Z}\approx 0.05$, the atomic stopping cross section $\epsilon$ in eV-${\mathrm{cm}}^2$ is given $\epsilon \times {10}^{15}=4\mathrm{}{\left(\frac{E_t}{Z}\right)}^{-\frac{1}{2}}-{\left(\frac{E_t}{Z}\right)}^{\frac{1}{2}}$, 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.