Range Measurements of Fission Products. I. Comparison with Stopping Theory

Range distributions in ${\mathrm{H}}_2$, He, Ne, and Ar, are reported for seven fission products (${\mathrm{Zr}}^{97}$, ${\mathrm{Mo}}^{99}$, ${\mathrm{Rh}}^{105}$, ${\mathrm{Pd}}^{112}$, ${\mathrm{In}}^{115}$, ${\mathrm{Te}}^{132}$, ${\mathrm{Ce}}^{143}$). The method of electrostatic collection of these products has been explored, and high collection efficiencies are observed for most products. The width of the observed distributions is resolved into a contribution from the stopping effects and a contribution from the fission process. The average range values and the stopping straggling are compared with the theory of Lindhard, Scharff, and Schiøtt. The differences between theory and experiment are ≈ 5 to 50%.