The history of mcfgen and mcfbin

The use of Monte Carlo methods for radiation transport at LLNL started with only neutrons and photons, and the code to do these calculations was tart, maintained by E. F. Plechaty. The library reaction data for tart was maintained by R. J. Howerton, and it was kept in binary files `endl' (for evaluated neutron data) and `egdl' (for evaluated gamma-ray data). R. E. Dye maintained the codes ctart and trtl to process this data to produce input files for tart, and documentation may be found in the omega manual [2]. Later, J. A. Rathkopf wrote a Monte Carlo code mcapm to keep track of several light-weight particles: neutron, proton, deuteron, triton, ³He, alpha, and gamma, and the coding to produce its data files was a part of omega called newct.

In the 1980s all of the data-processing codes, including ctart, trtl, and newct were merged into one big code omega [2]. Since then, the Code Group has dismantled omega into its components for reasons of maintenance. As computers and operating systems changed, it was easier to make reliable updates of several small codes one at a time than to change omega all at once. The computer code mcfgen is derived from newct. The most significant changes are that we have patched a number of memory leaks, and we added documentation. In many places we substituted clearer coding.