McStas - A neutron ray-trace simulation package
McStas is a general tool for simulating neutron scattering instruments
and experiments. It is actively supported by DTU Physics
, NBI KU
scattering from a hollow-cylinder vanadium
|The plot shows the intensity of scattered neutrons (red is
highest intensity). The sample is at the center of the sphere with the
neutron beam coming from the left. Clearly seen is the shadowing effect
of the sample causing a lower intensity opposite the beam. Also seen is
the effect of the non-symmetric geometry of the sample, causing lower intensity
directly above and to the side of the sample.|
October 11th, 2019: Respin of McStas v2.5 to support macOS Mojave
Recently one of our users reported issues on macOS Mojave with mcgui
not picking up the right location of the mcstas library, please see
the related GitHub issue
for more information.
Since the problem seems to occur consistently on updated Mojave
(10.14) and Catalina (10.15) systems, a patched version of our macOS
App bundle has been uploaded to our download page.
Please let us know via the
mailinglist or by creating a GitHub ticket if any further issues arise.
June 16th, 2019: Statistics on the history of McStas releases
Did you ever wonder how the number of included components and instrument files in McStas changed over time? - And did you know that we now include 215 components and 192 example instruments?
The figure below is generated from release-metadata extracted from
where all McStas releases can be found.
June 7th, 2019: math.h issues on macOS 10.14.5 Mojave
With the latest update to Xcode command line tools on macOS, there is no longer an option to install the system header files to the legacy location of /usr/include .
This unfortunately means that the miniconda-based gcc that we
distribute with McStas (and set up by default) is no longer able to locate the math.h header file and compilations fail with
mccode-r.h:39:18: fatal error: math.h: No such file or directory
Our suggested workaround is to configure your McStas installation
to instead use the system-provided clang compiler, see our GitHub
issue #799 for a detailed description of how to do this.
April 2nd, 2019: Announcing ISTSI2019
The workshop Innovative Simulation Tools, Shielding and
Instrumentation 2019 (ISTSI2019) will be held at Holiday Inn
St. Petersburg, Russia, on Saturday June 29th 2019, as a satellite of
the ECNS conference.
The workshop brings together the partners of the SINE2020 WP8 that have contributed work in the areas of
- Integrated simulation using neutronics and Monte Carlo ray-tracing
- Innovative Shielding Concepts and Materials
- Compact Instrumentation for Larmor Labelling applications at the
For more information and registration, please consult the website
This workshop / project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654000.
March 25th-20th, 2019: McStas School at CSNS
In collaboration with the China Spallation Neutron
Source, the McStas team participated in the first ever McStas
school in China in the last week of March.
All lecture material and exercises are available through our new
McStas school site, hosted on GitHub
Further, our hosts suggested we recorded videos of the lectures
which are slowly becoming available on the new McStas youtube channel.
January 18th, 2019: McStas survey results
The results from the 2018 McStas user survey are now online at http://survey2018.mcstas.org.
The main conclusions are that
- Q1: McStas users tend to upgrade to the latest release.
- Q2: Linux is by a large margin the most used platform, followed by Windows 10 and macOS.
- Q3: McStas are generally happy about the installation and use of the package. Very few people have issues with installation.
- Q4: The most used tool set is the default Python version, default since v. 2.1.
- Q5: McStas users seem very satisfied with the user support.
- Q6: McStas users tend to trust McStas to large extent. But please don't trust it blindly!!
- Q7: McStas users mostly compare with experimental data or analytic / back of envelope calculations.
- Q8: McStas users have widespread knowledge of all documentation resources - but we should probably disseminate the wiki further.
- Q9: The individual suggestions/questions/comments/... will be answered through individual GitHub issues.
- Q10: McStas is used on all continents that have / are planning neutron scattering infrastructure. Users are mostly based at these facilities, but also at other research labs or universities.
Thank you very much for the (generally) very positive review - also,
you are more than welcome to participate in continuing debate on user
suggestions that will take place in the individual GitHub
Previous news items: 2018, 2017, 2016,
2015, 2014, 2013,
2012, 2011, 2010, 2009,
2008, 2007, 2006,
2005, 2004, 2003, 2002, 2001, 2000, 1999,
Last Modified: Friday, 11-Oct-2019 09:30:01 CEST