Mass attenuation coefficients of β+-particles

The beta-spectra for the allowed transition and the first forbidden unique transition are calculated with enough accuracy. By applying them to the semiempirical transmission equation of monoenergetic electrons and positrons, we obtained the mass attenuation coefficients of beta-particles. The transmission characteristics of β+-particles are evaluated in terms of the ratios of the mass attenuation coefficients of β−-particles to those of β+-particles for the aluminum, copper, tin and lead absorbers. The mass attenuation coefficients of several β+-emitters are also tabulated. The calculated values for β+-particles are less than those measured by about 10–20%.