Measurements of the thermal defect for A-150 plastic (tissue-equivalent plastic)

Abstract

The quantity of deposited energy not resulting in the production of heat in irradiated A-150 tissue-equivalent plastic was measured calorimetrically. Several plastic samples, moulded at different laboratories, were studied to determine this quantity, which has been referred to as the thermal defect. Samples deliberately moulded at extremes of temperature and pressure were also used. Irradiations were carried out using protons accelerated to energies of 0.5, 1.7 and 4.0 MeV, and helium-3 ions of 4.0 MeV. Values of the thermal defect for these samples cluster about 4% for the range of radiations used in these experiments.