McStas - A neutron ray-trace simulation package

McStas is a general tool for simulating neutron scattering instruments and experiments. It is actively supported by Risø DTU, NBI KU, PSI and ILL

Simulated scattering from a hollow-cylinder vanadium sample.

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.



Recent news


July 15th, 2010: McStas 1.12b released!

The McStas developer team is happy to report that the 1.12b release of our software is finally out.

You can get the installer packages from our download page

McStas 1.12b is mostly a bugfix release, but some new components and example instruments have been included. McStas 1.12b will be the VERY last release in the 1.x series.

Part of the reason for McStas 1.12b and its late arrival is our delay in releasing the next major version, McStas 2.0.

McStas 2.0 will be released late 2010 / early 2011 and will introduce new features that could break ceartain backward compatibility, hence we move from the 1.x series. We are also considering a replacement of the GUI and plotting tools for McStas 2.0.

For a complete list of changes in McStas 1.12b, see our CHANGES document.

The new relase was tested on these platforms:


May 26th, 2010: McStas / VITESS user training workshop 2010 has ended

Last week, several McStas and VITESS team members teamed up organising a joint McStas/VITESS user training.

The event was generously sponsored by

The used teaching material has been made publicly available at http://ven2010.essworkshop.org/storage

A pre-release of McStas 1.12b was used by the participants, and this burn-in-test indicates that we can release a new stable McStas within a few weeks.

The organising committee would like to thank all participants, also for their very positive feedback about the event.


March 8th, 2010: McStas / VITESS user training workshop 2010

The McStas and VITESS teams are happy to announce the joint

McStas / VITESS user training workshop 2010

To take place at Backafallsbyn in the Swedish island of Ven, May 17th-21st.

The workshop is a school in order to train technical staff and instrument scientists in using Monte-Carlo code to design better neutron devices and instruments. The programme is split into sessions dedicated to different parts (optics, sample environment, detectors, ...). If you work in one of these areas, and feel like simulating it, then this school is for you, especially if you've never done so before.

Sponsorship / Participation / Cost
Generous support from our sponsors

has made it possible to offer sponsored lodging and participation for up to 25 people. If more than 25 people show an interest, a fee will be announced for further participation, that is the first 25 registrations will be free, the up-to-5 following will require accommodation charge (about 600 euros for the entire school).

We would like all participants to attend, as far as possible, the entire school.

All participants must arrange and pay their own transport to Copenhagen Airport. We will arrange joint transportation from CPH to the Island of Ven.

Further information

Please refer to http://www.essworkshop.org for further information and registration.


Previous news items: 2009, 2008, 2007, 2006, 2005, 2004, 2003,2002, 2001, 2000, 1999, 1998.