Intercomparison between photographic, thermoluminescent and radiophotoluminescent dosimeters

A comparison has been made between the responses of three different dosimetric systems, namely, photographic, thermoluminescent (TL) and radiophotoluminescent (RPL) dosimetry. The comparison was divided into two parts. The first one was carried out with known radiation conditions (exposure, normal incidence, energy) in a controlled environment (∼27°C temperature, ∼70% r.h.). Under these conditions, the response as a function of exposure and energy, the relation of the linearity to the energy, the lowest detectable exposure, and the reproducibility were studied. Response as a function of the exposure at 37 keVeff and at 1 MeV was found to be linear in the region of interest to routine personnel dosimetry for all dosimeters except the films. Although the film response is not linear with exposure, the ratio between the response at 37 keVeff and at 1 MeV does not depend on the exposure, and this allows the determination of a simple correction factor for the radiation energy. Such energy corrections are usually necessary, since all the dosimeters, except the LiF TL dosimeters are strongly energy dependent. In the second part, the relative response of the dosimeters was measured under the uncontrolled condition in personnel dosimetry. Because the CaSO4: Dy is the most sensitive dosimeter, comparisons were made using this dosimeter as the standard, in which case it was found that 20 out of 29 TLD-100 dosimeters gave the same reading within 30%, 13 out of 29 RPL dosimeters agreed within 30%, and only 3 out of 29 films fell within 30%.