Penetration of Electrons and Ions in Aluminum

The depth of penetration of 0.5- to 11-kev electrons and 1- to 25-kev H+, H2+, and He+ ions in aluminum has been measured. It has been found that the Thompson-Whiddington law for electrons does not hold for electrons having energies less than 10 kev. The practical range-energy relation obtained for electrons in aluminum was found to be R = KE1.3, where K is 0.042 if E is expressed in kev and R in microns. The practical range-energy relation for light ions in aluminum was found to be R = KE0.83 where K = 0.020 for H+, K = 0.021 for He+, and K = 0.015 for H2+ if E is expressed in kev and R in microns. Results are compared with those obtained by previous observers.