The MARS Code System User's Guide Version 13(95)

This paper is a user’s guide to the current version of the MARS Monte Carlo code. MARS performs fast inclusive simulations of three-dimensional hadronic and electromagnetic cascades, muon and low energy neutron transport in shielding and in accelerator and detector components in the energy range from a fraction of an electronvolt up to 30 TeV. The code has undergone substantial improvements since the last documented version MARS 10 and all these as well as other specific features of the MARS code system are explained in detail. Descriptions of general input and output with commentary and recommendations are given. Examples are given for running the program with distributed sources, complex compounds, arbitrary geometries, and magnetic fields. Use of the code in a multistage mode, coupled with event generators (DTUJET), with the STRICT program for tracking particles in accelerator lattices with beam loss recording, and with physics analysis and graphics packages is demonstrated with typical input and output examples.