Variance reduction unique to coupled electron/photon Monte Carlo transport

The disparity between the mean free paths of electrons and photons leads to unique variance reduction procedures for the coupled transport at intermediate energies. A variety of variance reduction features employed in the ITS (Integrated TIGER Series) code system are discussed. It is also discussed how these and more sophisticated procedures can be employed in combination to address a particularly difficult generic application. Finally, results obtained from a version of ITS that has been extensively modified to reduce the variance in a complex three-dimensional application are verified against linac experiments. (K.A.)