MinT: A Fast Lightweight Envelope/Monte-Carlo Beam Optics Code for the Proton Beamlines of the Paul Scherrer Institute

We report about the methods used in, and the performance of, the new fast and light-weight linear beam transport program MinT. MinT provides, beyond the usual linear ion optics, methods to compute the effects of beam degradation, multiple scattering and beam collimation. This is specifically important in facilities where the ion beam passes matter, for instance in proton therapy beamlines with an energy degrader as in the Proscan facility at PSI, but also for modelling the beam traversing the Muon- and Pion-production targets of the Paul Scherrer Institut's high intensity proton accelerator (HIPA). MinT is intended to be useful as a support tool for the HIPA and Proscan control rooms. This requires to have useful results within a few seconds. Hence simplicity and speed of calculation is favoured against higher accuracy. MinT has been designed not only to replace the FORTRAN 77 codes TRANSPORT and TURTLE, but to combine and extent their capabilities. MinT is a byte-code-compiler which translates an input language, described by syntactic rules. This allows for control structures like ``if-then-else'' or ``while''-loops, thus providing a high flexibility and readability.