ITS: the integrated TIGER series of electron/photon transport codes-Version 3.0

The ITS system is a powerful and user-friendly software package permitting state-of-the-art Monte Carlo solution of linear time-independent coupled electron/photon radiation transport problems, with or without the presence of macroscopic electric and magnetic fields of arbitrary spatial dependence. Version 3.0 is a major upgrade of the system with important improvements in the physical model. Improvements in the Monte Carlo codes include significant variance reduction from reorganized logic for electron trapping and Russian roulette, angular-dependent output of particle fluxes, explicit line radiation in flux and escape outputs, an option for photon transport only, more accurate sampling of collision loss straggling, extended implementation of full automatic subzoning, increased error checking, and extensive improvements in code clarity and maintainability