Calculations for high-energy radiations^*

Health Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.

Abstract

The theoretical high-energy dosimetry program, developed over the past decade in the Health Physics Division of the Oak Ridge National Laboratory, is described briefly. Some selected results are presented to illustrate the calculational capabilities that exist. These examples include depth-dose curves for broad, parallel beams of 2 GeV protons and 1 GeV neutrons incident laterally on a tissue slab and activation calculated as a function of depth in a water phantom exposed to a beam of 400 MeV neutrons. Because of their planned use in cancer radiotherapy research, pions are under extensive study. The Monte Carlo computer code, PION-I, was developed to calculate the penetration of pions in materials (containing H, C, N, and O) exposed to pion beams. Good agreement is found between calculated and measured curves in water. Calculated L.E.T. distributions at various depths are shown. The pattern of energy deposition around pion capture sites is analyzed. T-i kidney cell survival levels are predicted for pion beams based on data of Todd and on the survival model of Katz.