Monte Carlo simulation of Bremsstrahlung emission by electrons

Monte Carlo simulation of electron-photon showers has become a necessary tool for the characterisation of X-ray sources. Monte Carlo method involves the actual mathematical simulation of transport of the particle through the medium using random sampling techniques. Electrons, as they traverse through matter, lose energy by the following basic process, inelastic collisions with atomic electrons and the radiative loss, the emission of Bremsstrahlung photons. In addition to this, electrons undergo frequent elastic collisions with atomic nuclei, results in frequent change in electron direction. The Bremsstrahlung process becomes more dominant at higher energies. The rate at which electromagnetic energy is radiated from an accelerated charged particle is proportional to the square of the acceleration. The rate of radiative energy loss by the charged particle of z elemental charge and mass m, would be expected to be proportional to (Zz/m)2, where Z is the atomic number of the target. The resulting acceleration of the charged particle is proportional to this force and inversely proportional to the particle's mass m. The inverse square dependence on particle mass explains why Bremsstrahlung from protons or heavier charged particles is negligible compared to that from electrons or positrons. The dependence on the square of Z also explains why except for the lightest elements, Bremsstrahlung in the field of nucleus far exceeds that in the field of atomic electrons