Comparison of mass absorption coefficients of positive and negative beta particles in aluminum and tin

Mass absorption coefficients for six negative and three positive β-particle sources have been determined for aluminum and tin absorbers. Most of the large difference in the μ/ρ values relevant to ⁸⁶Rb and ⁶⁸Ga reported for aluminum by Takhar is shown to be due to the difference in their end-point energies; however, a significant difference in μ/ρ values for tin remains.