Frequency Distribution of Quasi-Effective Energy of Natural Radiation in Japan

Abstract

The quasi-effective energy of natural radiation, excluding the hard component of cosmic radiation, was evaluated at 768 sites in Japan using (a) an equation of relationship between the quais-effective energy and the quasi-exposure rates of natural radiation, and (b) the exposure rate of natural radiation already published. It is found that in Japan the mean quais-effective energy of natural radiation is about 1.03±0.25 MeV, and that it is larger in eastern than western Japan. This result reveals that, from the viewpoint of energy a 60Co gamma ray source is suitable for calibrating TL dosemeters and for the measurement of exposure rate from natural radiation.