The Range of Protons in Aluminum and in Air

Abstract

By the use of the two million volt generator developed at this laboratory the range of protons in air and in aluminum has been measured as a function of proton energy up to about 2 Mev energy. The range in air data are in good agreement with the theoretical values of Mano at high energies but diverge considerably at energies below 0.7 Mev. The ratio of the range in air to the range in aluminum has been found to increase from a value of approximately 1000 at 200 kv to a value of 1550 at 1200 kv. From 1200 kv up to the maximum voltage available the ratio is shown to remain nearly constant.