Dose measurements at the Philippine multipurpose gamma irradiation facility

The Philippine Nuclear Research Institute has recently set up a pilot scale multipurpose gamma irradiation facility. In January 1989, the irradiator was initially loaded with 1 PBq 60Co. Dosimetry measurements made during the commissioning and routine operation of the facility are described. Different dosimeter systems such as ethanol monochlorobenzene, red 4034 Perspex, potassium dichromate, GAMMACHROME YR and FWT-60 radiochromic film were used. The dosimeters were calibrated against a Fricke dosimeter. To determine the dose distribution in air, dosimeters were placed on polystyrene sheets, which were positioned at different distances from the source. The dose distribution and dose uniformity ratio in dummy products of different bulk densities, irradiated at different distances from the source, were determined. Two types of cardboard boxes, one for mangoes and the other for medical products, were utilized. Newspaper was used as dummy product to fill the boxes. The effect of vertical turning on dose uniformity ratio was also investigated. The dose distribution and uniformity ratio were also determined during the routine irradiation of onions and mangoes. (author). 7 refs, 4 figs, 6 tabs