ESR response of bulk samples of clear fused quartz (CFQ) material to high doses from 10 MeV electrons: its possible application for radiation processing and medical sterilization.

Clear fuse quartz (CFQ) could be a good candidate for dose measurements in the radiation processing of food material and in the sterilization of disposable medical and pharmaceutical products. In this study, bulk samples of CFQ materials were exposed to 10 MeV electrons at doses between 5-15 and 25-35 kGy; the dose ranges normally used for processing and sterilization. After irradiation, the samples were subjected to electron spin resonance analysis to test the intensity of their signal against the applied doses. The reproducibility of dose curve of the material to 10 MeV electrons was also studied, in which the dosed samples were annealed at 800 degrees C for 20 min and reused for further dose curve reproducibility investigation. The dose response curves of the reused samples showed a good linearity between the absorbed dose and the ESR intensity of the signals. They also indicated that the ESR intensity in the dose response curve, in both dose ranges, decreased by approximately 37% for the first reuse process and approximately 41% for the second reuse process of the samples in comparison to the first measurement. The thermal fading of the cylindrical samples of the CFQ, at room temperature, showed a sharp decay of approximately 20% over a period of 15 days, after which the decay-rate was negligible for a measured period of 60 days.