USE OF COMPUTER CODE FOR DOSE DISTRIBUTION STUDIES IN A CO-60 INDUSTRIAL IRRADIATOR

This paper presents a benchmark comparison between calculated and expe rimental absorbed dose values for a typical product, in a Co-60 indust rial irradiator, located at ININ, Mexico. The irradiator is a two leve ls, two layers system with overlapping product configuration with acti vity around 300kCi. Experimental values were obtained from routine dos imetry, using red acrylic pellets. Typical product was Petri dishes pa ckages. apparent density 0.13 g/cm(3); that product was chosen because uniform size, large quantity and low density. Minimum dose was fixed in 15 kGy. Calculated values were obtained from QAD-CGGP code. This co de uses a point kernel technique, build-up factors fitting was done by geometrical progression and combinatorial geometry is used for system description. Main modifications for the code were related with source sumilation, using punctual sources instead of pencils and an energy a nd anisotropic emission spectrums were included. Results were, for max imum dose, calculated value (18.2 kGy) was 8% higher than experimental average value (16.8 kGy); for minimum dose, calculated value (13.8 kG y) was 3% higher than experimental average value (14.3 kGy).