アルファ線計測器を用いた熱蛍光年代測定における年間線量の評価(都市基盤デザイン工学科)

Abstract

Contents of radiometric elements of U and Th have been determined using an alpha-counter. It requires rock samples less than 10g, which are much smaller than those needed for gamma- ray spectroscopy. Numbers of alpha-particles were counted in two ways: one being exposed (Air), and the other is with an aluminum foil cover (Al). The ratio of Air to Al gives a high correlation coefficient in multivariate equations to estimate the content of U or Th. Since all similar equations for K2O contents give smaller correction coefficients, it must be determined by other methods including x-ray spectroscopy. In conclusion, the grain method which measures the age of each grain, is recommended, of which the annual dose is determined by the techniques proposed here.