On the efficiency of azimuthal and rotational splitting for Monte Carlo simulation of clinical linear accelerators

This article presents rotational splitting as a modification to the sampling process of the azimuthal angle used in the variance-reduction technique of azimuthal particle redistribution, with the goal to improve the efficiency of this variance-reduction technique for the Monte Carlo simulation of radiation transport in clinical linear accelerators. Using a constant azimuthal angle, instead of a random one, in the azimuthal particle redistribution technique, increases the efficiency of the simulation of a clinical linear accelerator by about 30% and reduces the latent variance of a 10×10 cm2 phase space by about 40%.