Gamma-Ray Dosimetry by means of Proportional Counter, (I)Fundamental Characteristics of Plastic Wall Counter

摘要

The relation between exposure rate and energy loss of secondary electrons in the sensitive volume of a plastic wall counter was derived. The possibilities presented by a proportional counter for use in dosimetry were examined for the case of a combination of polyethylene wall and methane gas. Absolute measurement was found possible by calibration of the observed pulse-height distribution. It was also shown that low exposure rates could be effectively measured with counters provided with small sensitive volume. The characteristics of the counter when used as dosimeter proved very close to those of an ionization chamber.