McXtrace - An X-ray ray-trace simulation package

The software package McXtrace is a tool for carrying out highly complex Monte Carlo ray-tracing simulations of X-ray beamlines to high precision. The simulations can compute all aspects of the performance of instruments and can thus be used to optimize the use of existing equipment, design new instrumentation, and carry out virtual experiments for e.g. training, experimental planning or data analysis. McXtrace is based is based on a unique design, inhereted from its sister McStas, 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. This report constitutes the reference manual for McXtrace, and, together with the manual for the McXtrace components, it contains full documentation of all aspects of the program. It covers the various ways to compile and run simulations, a description of the meta-language used to define simulations, and some example simulations performed with the program.

This report documents McXtrace version 3.9, released September, 2026

The authors are:

Erik B Knudsen <erkn@fysik.dtu.dk>
Physics Department, Technical University of Denmark, Kgs. Lyngby, Denmark.

Peter Kjær Willendrup <peter.willendrup@risoe.dk>
Physics Department, Technical University of Denmark, Kgs. Lyngby, Denmark.

Emmanuel Farhi <emmanuel.farhi@synchrotron-soleil.fr>
Synchrotron SOLEIL, Saint-Aubin, France

Kim Lefmann <lefmann@fys.ku.dk>
Niels Bohr Institute, University of Copenhagen, Denmark

other people connected to the project:

Jana Baltser  <jana.baltser@fys.ku.dk>
Niels Bohr Institute, University of Copenhagen, Denmark

Andrea Prodi  <aprodi@fys.ku.dk>
Niels Bohr Institute, University of Copenhagen, Denmark

Manuel Sanchez del Rio
Computer Science Department, ESRF, Grenbole, France

Claudio Ferrero
Computer Science Department, ESRF, Grenbole, France