Experimental data from irradiation of physical detectors disclose weaknesses in basic assumptions of the δ ray theory of track structure

The applicability of track structure theory has been tested by comparing predictions based on the theory with experimental high-LET dose-response data for an amino acid alanine and a nylon based radiochromic dye film radiation detector. The linear energy transfer LET, has been varied from 28 to 20200 MeV.cm2.g-1 using ion beams ranging from protons to sulphur ions. The low-LET reference radiations were beams of fast electrons and of 60Co γ rays. At doses well below saturation the two detectors act upon low-LET radiation in close accordance with the theoretical considerations, but at marginal high doses dose-rate effects are observed obscuring the evaluation of important parameters. Basic concepts in the theory have been investigated are shown to be inappropriate in the present formulation