Abstract
A new attempt has been carried out for providing an additional function of particle identification for the imaging plate of two-dimensional position sensitive device. This proposed method is based on the statistical feature that PSL intensity recorded in a small pixel may suffer from fluctuation even though the PSL intensity seems to be almost uniform in a larger area. Dividing a scan area of about 3 mm square into more than 1, 000 pixels of 0.1 mm square, frequency distribution in PSL intensity became sharper with increasing β-ray irradiation time. The broadness was quantified by the standard deviation obtained by fitting measured distribution to Gaussian. It was experimentally confirmed that the standard deviation for α-rays was much higher than that for β-rays on the condition of the same average PSL intensity, which means that α-and β-rays can be successfully discriminated by the proposed method. From a viewpoint of practical application to monitoring of radioisotope contamination in controlled area, two problems were also investigated concerning about the mixed irradiation of α-and β-rays and the minimum scanarea for deriving distribution.
