FLUKA Monte Carlo calculations for angular distribution of bremsstrahlung photons from thin targets

Highlights: • The bremsstrahlung angular distribution was investigated for thin targets. • Optimum thicknesses were obtained for Au, W, Gd, Ag, Mo, Nb, Cu, Fe, Si, Al. • The variation of the photon intensity was calculated depending on the thickness. • The comparison, the angular distributions for 20 and 40 MeV energies of the electron beam. -- Abstract: This study reports calculations of the angular distributions for the bremsstrahlung photons emitted from different targets using the FLUKA Monte Carlo code. For electron beams with 20 and 40 MeV energies, photon fluences dependent on scattering angles of photons obtained from the thin Au, W, Gd, Ag, Mo, Nb, Cu, Fe, Si, Al targets with optimum thicknesses (2 μm−100 μm) were considered. At the same time, optimum thicknesses of the targets with low to high Z number were calculated by taking the radiation lengths of the targets into consideration. The changes in photon fluence connected to the scattering angle and atomic number of the bremsstrahlung photons obtained from the targets with optimum thickness were investigated. The results of this study will be benefit for medical physics applications and accelerator facilities that require knowledge of angular distributions of photons for accurate fluence calculations with Monte Carlo based methods.