Developers meeting​​

In early November 2025, the Mantid team in ISIS welcomed colleagues from other facilities that also develop the Mantid Open-Source software for a developers meeting. Mantid provides tools to support the processing of materials-science data, which can be gathered from neutron scattering or muon spectroscopy experiments, or as the result of simulation. 

Groups joined from facilities in France (Institut Laue-Langevin, ILL), Germany (Forschungszentrum Juelich), China (Chinese Spallation Neutron Source, CSNS) and online from the US (Oak Ridge National Lab, ORNL). It was a successful three days that included a code camp, talks and a hackathon design session. “Most of all, it was a great opportunity to build collaborations and to learn more about what each facility is doing from a software engineering point of view," explains Sarah Foxley, the developer meeting lead. 

During the code camp, developers worked on adapting the new Texture Analysis workflow, recently developed as part of a joint ISIS/PSI project, for use on a CSNS beamline. Another group of developers looked integrating a Large Language Model (LLM) service into workbench to allow users a more interactive experience when looking for help with Mantid. If you have used ChatGPT, Claude or CoPilot then you will have experience of using an LLM! 

In addition to those two large pieces of work, developers fixed Gaussian peak fitting and planned how to convert some of our manual testing into automated unit testing. We also worked on improving the quality of the code by fixing cppcheck errors – errors in the C++ code base of Mantid as identified by the cppcheck software. 

There were a wide range of talks covering science concepts, facility specific work and technical ideas. This included:

• optimisation of outliers using modified weighted least-squares for better fitting
• writing clearer release notes for users to understand
• using Mantid in a browser
  
• autoreduction at ORNL
• cybersecurity
• a project to reduce reliance on the obsolete NeXus API

In addition, there were extended sessions looking at GitHub Actions, modularising Mantid and the use of AI tools for development. 

Above, attendees of the developers meeting. 

User meeting​​​

The week continued with a user meeting, which saw users and developers joining both in-person and remotely worldwide. The day included a mix of scientific and technical talks, facility updates about the Mantid project and discussion about upcoming features. 

The morning session focussed on understanding the future role of the Scientific Roadmap Working Group (SWG) and user meeting within the project, considering how these entities might evolve to better serve the work. Toby Perring gave an excellent review of the project (now 18 years old), highlighting the many reasons why Mantid has been so successful in providing facilities with robust tools for data reduction. Thoughts about the SWG and user meeting were shared by Anna Sokolova (Australia's Nuclear Science and Technology Organisation, ANSTO, SWG chair) and Steve Cottrell (ISIS, user meeting chair), respectively, with Anders Markvaardsen from ISIS bringing things together in an open discussion that allowed participants to share ideas about the overall organisation and governance of the project. 

The remainder of the day was spent on project updates, firstly from the chair of the Technical Roadmap Working Group (Peter Peterson, ORNL), and then from facilities, including the Australian Centre for Neutron Scattering (Anna Sokolova), ISIS (David Voneshen), Spallation Neutron Source (Jonathan Taylor), ILL (Stephane Rols), CSNS (Rong Du) and Heinz Maier-Leibnitz Zentrum (Oleksandr Koshchii). Interspersed with these updates were a number of talks illustrating the contribution Mantid is making to data reduction and analysis across a broad range of application areas. 

The meeting website remains live, where recordings of talks and slide decks are being uploaded for future reference. The meeting organisers Sarah and Steve are always happy to receive feedback and ideas for future meetings. 

It was a successful week, and all agreed they look forward to future meetings in the coming years. 

​Above, attendees of the user workshop. 

Sarah Foxley (Developer Meeting Lead)

Stephen Cottrell (User Workshop Lead)