Abstract ID: 10 Monte Carlo based validation of Compton scattering for 5 MV and 10 MV photon beams using aluminium and tungsten targets

Abstract

The scattered photon energy spectrum from Tungsten and Aluminium target for photon of energies 5MV and 10MV have been studied at angle 0, 45, 90 degree and in target region by using EGSnrc based FLURZnrc Monte Carlo code. Photon cross section calculations are briefly reviewed by HJ Hubbell [1] . The physical interaction models and approximations for electron and photon transport which are used in Monte Carlo Simulation codes are reviewed by Salvet et al. [2] . Parallel monoenergetic photon beam of radius 0.1 cm was made incident on target of thickness 1 cm and radius 1 cm. All the spectrums are scored in 1 × 1 cm2 area at 10 cm distance in vacuum. Verification and validation of EGSnrc Monte Carlo code with the Compton scattering formula is done for Cs-137 and Co-60 and results are found in good agreement. It is observed that presence of energy spread of scattered photon of energy 0.4 MV and 1.4 MV for 5 MV and 10 MV photon beams respectively at an angle of 0 degree for both the target materials. The calculated energy of scattered photon at angles 0 and 45 degree are consistent with Compton scattering formula. It is observed that Compton scattering formula does not give correct value for energy of scattered photon for both photon energies of 5 MV and 10 MV at an angle of 90 degree when compared with the Monte Carlo results. Calculation of total fluence in all region of interest involves photons of energy 0.511 MV which are created in annihilation process.