The Maximum Range of High Energy Electrons in Aluminum and Copper

Abstract

The practical maximum range of monoenergetic electrons in aluminum and copper has been measured in the region of energy from 3 to 12 Mev. The magnetically analyzed beta-ray spectrum of ${\mathrm{B}}^{12}$ was employed, range values being determined from absorption curves obtained with a triple coincidence counter train. The values so obtained fall below a semi-empirically computed curve normalized with experimental data in the region of electron energy below 3 Mev. It is shown that the discrepancy can be explained if the influence of multiple scattering effects in the absorber is considered. On this basis the data indicate that the difference between the "absolute maximum range" and the "practical maximum range" increases with electron energy.