Theoretical evaluation of dose distribution in product in radiation processing plants

An analytical method has been developed for the computation of dose rates at any number of points in the product material in a radiation processing plant in which radioactive source pencils are arranged in a rectangular vertical frame. Exposures from each individual source pencil and the movement of the product box was taken into consideration for the evaluation of absorbed dose. The validity of the computational method was tested for one of the existing irradiator already in operation. Excellent agreement was achieved between the computation and measured values of doses received by the product material. The method was then applied in the design of a new irradiator and was found very useful to arrive at optimum source size and target size. Hence, this method is being adopted for the design of all forthcoming 60Co irradiation plants in India.