Attention ** Sign up for TOPAS Announcements Email List** Get updates on user meetings, code releases, and more. For more, see https://github.com/OpenTOPAS/OpenTOPAS/discussions/185 Variance Reduction# Introduction Specify the Split Geometry Define the Splitting Technique Geometrical Particle Splitting Importance Sampling Weight Window Tracking Only Specific Particles Secondary Biasing Forced interaction Periodic Boundary Condition Cross section enhancement