Establishment of accurate and reliable methods for estimation and measurement of the absorbed dose is an urgent need in using low-energy electron accelerators. For the purpose of giving a firm basis for the estimation of the absorbed dose, experimental investigations on transmission and backscattering have been made for electrons of energies most utilized in industrial applications, i. e. 200-400 keV. By using the results obtained, an empirical formula expressing the absorbed dose under a practical condition of irradiation parameters has been developed for the case of 300 keV electrons. In order to find a practical and reliable method of dosimetry, characteristics of various film dosimeters have been studied ; the characteristics considered are linearity of response, accuracy, and fading effect. Inaccuracy of optical measuring devices for films has also been revealed in this study. Preparation of a manual describing, standardized treatments in film dosimetry and centralized supply of films are considered to be necessary for the advance of irradiation engineering.
