Ary De Araujo Rodrigues Junior

Small Ionization Chamber: for High Dose Measurements Ary De Araujo Rodrigues Junior

Industrial gamma irradiators are designed for processing large amounts of products, which are exposed to large gamma radiation doses. The irradiation, in industrial scale, is usually carried out in a dynamic form, where products go around a Co-60 gamma source with activity of about PBq (MCi). In some situations (research purposes or validation process according to norm ISO 11137), it is required to irradiate small samples within fractional deliver doses. Samples are placed inside the irradiation room at a fixed distance from the source and the dose is usually determined by using dosimeters, therefore the dose is only known after completed the irradiation. Usually different kinds of products with different densities go through between the source and static position samples. So, the dose rate varies in function of product density. A suitable methodology would be to monitor samples dose in real time, which would improve dose accuracy, avoiding the overdose. A cylindrical 0.9 cm3 ionization chamber has been developed for high-doses real-time monitoring, when the sample is being irradiated at a static position in a Co-60 gamma industrial plant.