Identification of ionizing radiation with an imaging plate using two-wavelength stimulation light

Imaging plates are widely used in various fields. However, ordinary reading instruments give no information on the type of radiation. We proposed that radiation type can be identified by stimulation with light of two wavelengths. Recently, we have carried out further investigation and found that the intensity ratio of photostimulated luminescence (PSL) between two wavelengths depends on particle properties. Imaging plates were irradiated with 3.2 MeV protons, 40 kVp X-rays, 200 keV electrons and Co-60, and stimulation spectra were observed for each type of radiation. We compared the PSL intensities at 500 nm with those at 600 nm 18 hrs after irradiation. The PSL intensities at 600 nm normalized by those at 500 nm were observed to decrease in order of irradiation with 3.2 MeV protons, 40 kVp X-rays, 200 keV electrons and Co-60.