McXtrace - Monte Carlo Xray Tracing, is a joint venture by

DTU_logo.gif B_NAT_cmyk.png ERSF_logo.png SAXSLab ApS.

Funding from NABIIT, DSF and the above parties.

Our code is based on technology from mcstas_logo_thumb.png.

Code repository (shared with 'McStas') is located at

For information on our progress, please subscribe to our user mailinglist..

McXtrace News

The latest McXtrace news.

McXtrace 1.4: workaround for a python issue on windows 10

[27/11/2017] A reported issue with McXtrace 1.4 and numpy has found a workaround. The procedure below has been reported to work, if when starting an McXtrace simiulation for the GUI, you happen to see error messages complaing about missing dlls and at the end of them (there can be a lot) find something like the following:

File "C:\mcxtrace-1.4\miniconda3\lib\site-packages\numpy\core\", line 14, in 
from . import multiarray ImportError: DLL load failed ...
If this applies to you then you may try this, which has been reported to work:
  1. Move the numpy folder in the miniconda3 folder c:/mcxtrace-1.4/minoconda3/Lib/site-packages/numpy out of the way.
  2. Start a mcxtrace shell session
  3. In the shell, issue the command: pip install numpy

McXtrace 1.4: known bugs

[16/08/2017] A list of known bugs in the McXtrace 1.4 dsitribution. These will be fixed in an upcoming 1.4.1.

McXtrace 1.4 is released!

[23/06/2017] The McXtrace team is proud to announce that McXtrace 1.4 has finally been released. In the first step packages are made available for debian systems, while the testing trolls do their work on the rpms and windows file to make sure the installation procedure runs as smooth as possible. Fortunately testing trolls do not celebrate Swedish midsummers' eve. New features of 1.4 (pasted from the CHANGES file):
  1. Source_pt, Source_flat, Source_gaussian, and Source_div now behave in the same manner wrt. phase. The relevant parameters are randomphase and phase. If randomphase is !=0 the phase is completely random, if ==0 the value of phase is used.
  2. EPSD_monitor: Has a parameter nE which denotes a number of energy bins. if >1 the monitor will output a number of files. each corresponding to an energy bin.
  3. Lens_parab, Lens_parab_Cyl The functionality of the _rough versions of these components have been merged into the main components and the _rough versions themselves retired.
  4. Support for binary file dump of photons in the mcpl-format is added.
  5. On debian class systems, McXtrace now installs to /usr/share to be more standards compliant.
  6. New Components:
  7. Example Instrument simulations:
  8. New python/Qt based GUI/plotting tool
  9. PowderN: incoherent scattering (computed from tables)
  10. Curved Bragg monochromator crystal, Major improvements to the flat Bragg monochromator crystal
  11. Output in the NeXus-format.
  12. Data files (such as photoelectric absorption spectra) can be read once and reused by other components without further disk IO overhead.

Bug in PowderN.comp

A bug has been found in PowderN shipped with McXtrace 1.2. It results in underestimating absorption substantially. A patch has been commited to the devlopment tree which may be downloaded from PowderN.comp. Thanks to the groups at University College London and Cranfield University for reporting this.
Older News

McXtrace Manual

A manual is "under construction". A rough draft version is available here. From now on, we will upload nightly builds of the manuals here: nightlies.

A printed, bound version is planned using a Print-On-Demand scheme.

This is work in progress and may contain significant omissions and inaccuracies but for the interested it may be downloaded here:

The User manual documents the use of the McXtrace system whereas the Component manual details the inner workings of the models employed in the components, in other words the interaction physics between devices and beam.

McXtrace Code Development

The code development page has more info on code details

Art Gallery

We've established a gallery of plots which are beautiful/funnny or otherwise interesting at McXtraceArt. Please take a look and be inspired!

Steering Committee Meeting Minutes

You may now access the minutes of the steering committee meetings