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McStas - A neutron ray-trace simulation package
|
| 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. |  |
Simulated
scattering from a hollow-cylinder Recent news
Migrating from McStas 2.x to 3.x? - Use the wiki-based guides
April 13th, 2026: McStas and McXtrace 3.6.14 released
Installation instructions
- For McStas go to The McStas install page on GitHub
- For McXtrace go to The McXtrace install page on GitHub
What's Changed
(Selected items, please consult the GitHub changelog for full set)
New comps/instruments
New tool feature: NeXus scans become entries in one common HDF file
Various updates to instruments/components/data files
- Fix Union mcdisplay bugs by @Lomholy in #2294
- Fix to MPI-mode use of Brilliance Transfer calculation. by @willend in #2300
- Minor instrument and comp updates, McStas by @willend in #2332
- More %Example tests for McStas instruments by @willend in #2333
- More additions of McStas %Example lines by @willend in #2337
- Update of McXtrace Incoherent_process comp from EBK branch by @willend in #2338
- Add more %Example lines to McStas instruments by @willend in #2341
- Add Test instrument for Be-filter models by @willend in #2349
- Re-enable a few tests on the nightlies by @willend in #2364
- ESS_butterfly: Wrap all printf / fprintf in MPI_MASTER( ); by @willend in #2372
- Updated Rubredoxin lau file from @aaronfinke by @willend in #2384
- Updated Example values following updated Rubredoxin.lau by @willend in #2386
- Adapt Guide_m interface -> style of Guide_gravity parameters by @willend in #2389
- McStas Monitor_nD “nexusbins” only in listmode by @willend in #2387
- Mono bent complex string parsing by @Lomholy in #2395
Various tool improvements
- mctest / timeout system - ensure to kill underlying processes by @willend in #2363
- Add timers for maximal compile / runtime in mctest by @willend in #2356
- Add hints for alternative mcdisplay visualisation in Jupyter... by @willend in #2353
- mcrun -L list was broken, fixed here by (re-)calculating number of elements … by @willend in #2377
- Changed (hard-coded) mcgui 3D visualiser to be webgl-classic by @willend in #2381
- On Windows use psutil for probing number of available cores in MPI by @willend in #2367
Other changes
Please consult the GitHub changelog
- Fixes to various bugs
- LaTeX in doc headers
- Clang-format formatting of component syntax
- Various updates to project infrastructure: PR template, CI etc.
- Various GPU related fixes
New Contributors
Full Changelog: v3.6.5...v3.6.14
March 31st: First circular: PHOTONS AND NEUTRONS REALISTIC ARTIFICIAL INTELLIGENCE DATASETS (PaNRAID)
Dear Colleagues,
In collaboration with the French DIADEM Academy, we invite interested participants to attend the following course in September:
 | PHOTONS AND NEUTRONS REALISTIC ARTIFICIAL INTELLIGENCE DATASETS (PaNRAID) | |
Dates: 21-25 September
Location: Île d’Oléron, France
Objective
The course will develop an integrated approach for generating synthetic data for supervised learning. This approach combines multi-scale materials simulations (DFT, MD, XAS spectroscopy) with comprehensive digital twins of experimental X‑ray and neutron facilities, explicitly accounting for instrumental effects and experimental artefacts.
Intended audience
- Doctoral students
- Postdoctoral researchers
- Faculty and teaching-research staff
- Researchers and research engineers
Further information and pre-registration: https://formation.pepr-diadem.fr/formation-panraid
Attached are PDF flyers in French and English.
Best regards,
Peter Willendrup
March 28th, 2026: McStas 2.x and McXtrace 1.x formally out of support
Dear all,
We have decided to formally declare that we no longer support McStas 2.x and McXtrace 1.x, so user issues with these released will from now on always prompt us to request that you upgrade.
If you are still running such an old release, please upgrade and
port your comps/instruments using the information in the use the wiki-based
porting-guides
We are of course at your service if you have issues porting your
existing code, please create a GitHub issue.
Dear all,
In connection with a user request I realised that occasionally we may all benefit from easier access to old McStas variants.
I have therefore put together a "Best of McStas compilation" - a Linux image with McStas version 1.12c, 2.7.2 and the latest 3.6.8.
You can give the image a quick trial spin via binder:
Or alternatively pull docker.io/mccode/mcstas_v1.12c_v2.7.2_v3.6.8:latest via Docker / podman / etc., i.e. something like
Best and hope this may be useful,
Screenshot of the running compilation:
What's Changed - Main Changes:
Full Changelog:https://github.com/mccode-dev/McCode/compare/v3.6.1...v3.6.5
Previous news items: 2025, 2024,
2023, 2022, 2021,2020,2019, 2018, 2017, 2016,
2015, 2014, 2013,
2012, 2011, 2010, 2009,
2008, 2007, 2006,
2005, 2004, 2003, 2002, 2001, 2000, 1999,
1998.
March 13th, 2026: "Best of McStas compilation"
https://mybinder.org/v2/gh/mccode-dev/jupyter-mcstas-mcxtrace-desktop/HEAD?urlpath=desktop
(will not in practice sustain much actual work / load)
podman run -p 8888:8888 docker.io/mccode/mcstas_v1.12c_v2.7.2_v3.6.8:latest
Peter
January 7th, 2026: McStas and McXtrace 3.6.5 released
McStas and McXtrace release 3.6.5 is now available.
McStas installation instructions are found on GitHub .
Bugfixes, new features, all common to McStas and McXtrace:
Other stuff
