Monte Carlo calculations of the energy response of lithium dosemeters to high energy electrons (

Abstract

Calculations for LiF dosemeters have been carried out to help resolve the discrepancy between the measurements of Holt et al. (see ibid., vol.20, p.559, (1975)) and those of Paliwal and Almond (see ibid., vol.20, p.547 (1975)) and others. It is concluded that the assumptions used by Holt et al. are largely responsible. They assume, in converting energy deposition in an air-filled ionization chamber to energy deposition in water, that as electrons penetrate a medium they are monoenergetic and the energy is given by Harder's expression (ICRU Report 21, 1972). The assumption gives poor results as the stopping power for electrons in air is strongly energy dependent, and the energy spectrum has been significantly broadened. The Monte Carlo calculations are also used to criticize some electron cavity theories and to suggest as an alternative a slightly modified version of the Bragg-Gray theorem.