An analytical method based on multipole moment expansion to calculate the flux distribution in Gammacell-220

作者：Rezaeian P^*; Ataenia V; Shafiei S

来源：Radiation Physics and Chemistry, 2017, 141: 339-345.

DOI：10.1016/j.radphyschem.2017.08.003

• Flux distribution
• Multipole moments expansion
• Gammacell-220
• MCNP simulations
• Amber dosimeters
• Levenberg-Marquardt algorithm
• Source load planning

In this paper, the flux of photons inside the irradiation cell of the Gammacell-220 is calculated using an analytical method based on multipole moment expansion. The flux of the photons inside the irradiation cell is introduced as the function of monopole, dipoles and quadruples in the Cartesian coordinate system. For the source distribution of the Gammacell-220, the values of the multipole moments are specified by direct integrating. To confirm the validation of the presented methods, the flux distribution inside the irradiation cell was determined utilizing MCNP simulations as well as experimental measurements. To measure the flux inside the irradiation cell, Amber dosimeters were employed. The calculated values of the flux were in agreement with the values obtained by simulations and measurements, especially in the central zones of the irradiation cell. In order to show that the present method is a good approximation to determine the flux in the irradiation cell, the values of the multipole moments were obtained by fitting the simulation and experimental data using Levenberg-Marquardt algorithm. The present method leads to reasonable results for the all source distribution even without any symmetry which makes it a powerful tool for the source load planning.

• 出版日期2017-12