Degradation and Range Straggling of High-Energy Radiations

Abstract

A general analysis of the energy spectrum resulting from the degradation of ionizing radiations is presented in part A (Secs. 2-6) and of the range-energy straggling in part B (Secs. 7-13). A method for calculating the energy spectrum is developed, which requires that the differential cross sections of successive collisions are nearly equal. This method is applied to the slowing down of mesons and other heavy charged particles (Sec. 6). The same requirement on the cross section for successive collisions underlies the analysis of straggling into contributions from separate energy intervals traversed in the course of degradation. Successive approximation formulas for the straggling parameters (cumulants) are derived (Sec. 12) and applied to the case of heavy charged particles (Sec. 13). The connections among the theoretical approaches of several authors are discussed.