McStas – neutron ray-trace simulation software

McStas is an open source software simulator for neutron scattering instruments and experiments. The software consists of a compiler that translates instrument and component definitions to C code.

McStas is based on a compiler that reads a high-level specification language defining the instrument to be simulated and produces C code that performs the Monte Carlo Simulation. The system is very fast in use, both when setting up the instrument definition and when doing calculations.

McStas is based on a unique design where an automatic compilation process translates high-level textual instrument descriptions into efficient ANSI-C code. This design makes it simple to set up typical simulations and also gives essentially unlimited freedom to handle more unusual cases.

Features include:

  • Very fast in use.
  • Supports triple-axis.
  • Supports time-of-flight instruments.
  • Supports polarised neutrons.
  • Library of well-tested components that include most standard elements of neutron scattering instruments, including steady-state and pulsed sources, monochromators/analysers, guides, collimators, vanadium and powder samples, velocity selectors and choppers, and a variety of detectors.
  • Generates histograms (tallies) as formatted (easy to read) text files. Such text files may be read by the McStas internal plotter using PGPLOT, but also using Matlab, Scilab, VRML/HTML (web page), HDF/NeXus, XML/NeXus, Octave, IDL and more.
  • Comprehensive manual.

Support: Manual
Developer: Risø / ILL / KU
License: GNU Lesser General Public License


McStas is written in C. Learn C with our recommended free books and free tutorials.

Return to Physics Tools | Return to Ray Tracing

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