Analysis of latent variance reduction methods in phase space Monte Carlo calculations for 6, 10 and 18Â MV photons by using MCNP code

► The efficiency of APR and APRS methods was compared to two tallying methods. ► The APRS is more efficient than the APR method in track length estimator tallies. ► In the energy deposition tally, both methods have nearly the same efficiency. ► Variance reduction factors of these methods are position and energy dependent.