Thermoluminescent response and the effect of exposure order from mixed photon and proton irradiations

Two types of thermoluminescent dosimeters (TLDs): Harshaw LiF:Mg,Ti (TLD-100) and CaF2:Tm (TLD-300) were investigated for their glow curve responses to separate, mixed field, and simultaneous X-ray and proton irradiations. All TLDs were exposed to X-rays produced by a 30 keV, 0.2 mA electron beam, X-ray tube source. TLD-100 detectors were exposed to 2.5 MeV protons and the TLD-300 detectors were exposed to 4 MeV protons. The following five separate irradiation schemes were used: only X-ray, only proton, first X-ray then proton, first proton then X-ray, and simultaneous X-ray and proton beam exposures. Computerized glow curve deconvolution based on first order TL kinetics was used to analyze the resulting glow curves for any differences in shape and TL efficiency due to order of exposure. We found no significant differences in glow curve shape or magnitude attributable to radiation exposure order.