Evaluation of Range Straggling for Heavy Particles

Abstract

From the formula developed by Lewis for the differential range distribution of heavy, charged, non-relativistic particles, an integral range distribution is obtained. The latter is evaluated for 2- to 500-Mev protons in Al to show, in a practical way, how the distribution differs from a Gaussian, as evidenced by its shorter-than-average range tail. The extent to which this tail increases the mean range and makes it different from the most probable range is indicated. Values for the range straggling are also given.