Abstract
Quantitative measurements have been made of the total number of positive charges produced per electron per cm path at a definite pressure, in helium, neon, and argon, as a function of the energy of the impacting electrons out to 4500 volts. In helium the maximum efficiency 1.256 occurs at 110 volts, in neon 3.008 at 170 volts, and in argon 13.01 at 88 volts.