Calculation of dose uniformity ratio in irradiation cell of GC-220 using analytical method based on multipole moment expansion‎

‎In this paper‎, ‎dose uniformity ratio in irradiation cell of GC-220 is specifiedutilizing an analytical method based on the multipole moment expansion‎. ‎In this method‎, ‎the values of monople‎, ‎dipole and quadrupole moments for source arrangements of GC-220 are calculated by numerical integrating‎. ‎Appling these values‎, ‎the dose uniformity ratio in the irradiation cell of GC-220 is calculated equal to 1.92‎. ‎Monte Carlo simulation is applied to validate calculations‎. ‎There is a relative difference about 12% between the results obtained from the analytical calculation and Monte Carlo simulation‎, ‎which confirm the used method‎. ‎In comparison with Monte Carlo methods‎, ‎this method is not time consuming‎, ‎so‎, ‎this method can be used for the conceptual designing and the source load planning of irradiators‎.