2025 operations: highlights

The ILL concluded 2025 operations at the end of October. in total, more than 1800 scientists came on site to perform close to 1400 experiments. The high-flux reactor will RESTART IN late March 2026 for a year with 3 OPERATING cycles in the programME.

The ILL concluded 2025 operations at the end of October. The High-Flux Reactor restarted in early May and operated for a total of 126 days, divided equally into two cycles of 63 days. In total, 1811 scientists from 40 countries came on site to perform some 1393 experiments. With the oficial completion of the Endurance upgrade programme in 2024, the last instruments and systems are now coming into operation. Some of the milestones achieved are highlighted below.

During the last cycle of the year, the new imaging instrument PorTo was commissioned. During commissioning, a detailed tomography of a porous polycarbonate foam mimicking cancellous bone microstructure was captured. The system is now fully operational and its dedicated high-resolution detectors fully commissioned. In its first week of operation, PorTo joined the other imaging instruments NeXT and MoTo in running user experiments simultaneously for the first time. PorTo alone welcomed nine experiments spanning cultural heritage, energy storage, and next-generation battery materials, with users coming from 15 different institutions. A dedicated news item on PorTo has recently been published.

Two other instruments welcomed their first teams of users to perform experiments: SHARPER, during the first cycle, and D007, in recent weeks. The first user measurements on SHARPER were performed with PhD student Phillip Eckstein, working on a joint PhD project between the ILL and the Institute of Frontier Materials of the German Aerospace Center (DLR) - see dedicated news item here. At D007, diffraction data obtained on powders and single crystals were visualised and processed using algorithms developed using the Mantid software, and at least one publication has been already submitted to a scientific journal.

The DALI instrument team has recently built and installed a completely new image plate detector. This greatly enhances the performance of the instrument, allowing users to study large proteins at high resolution. The first neutron diffraction pattern using the new detector have been obtained - see dedicated news item.

During the last cycle, the MARMOT system was successfully tested and validated on a prototype (with seven detection channels). The next step will more than triple the detector’s active surface area, making MARMOT even more efficient. MARMOT is the latest major technical breakthrough in neutron spectrometers. Designed and built in-house at the ILL, it offers a new way to analyse the energies of neutrons across a wide range of angles. It is based on an innovative bent silicon crystals technology, which enables new designs for monochromators and analysers specifically tailored to enhance inelastic neutron scattering experiments.

The ILL also welcomed the first 'novice users' as part of the NEPHEWS Twinning exchange programme. In various stages of their careers and discovering the ILL for the first time, portraits of these users can be found in these 3 videos and in this article.

Complex sample environments are one of the trademarks of neutron experiments – in particular the low temperatures, high pressures and high magnetic field conditions in which new quantum states emerge. In May 2025, and for the first time ever, an experiment was conducted with a sample under a proessure more than 200 000 times atmospheric pressure at a temperature of 1/10th of a degree above absolute zero. The experiment was conducted on the ILL instrument XtremeD. The results are now published and highlighted in a recent website news story here.

Togehter with the most intense neutron beams in the world, a unique instrument suite and state-of-the-art sample environment services, the ILL offers its users a comprehensive set of Support Labs with unique capabilities. During the two 2025 operating cycles, these Support Labs made more than 350 experiments possible.

On the software side, automatic data reduction is now operational on ILL instruments. After a period of offline testing and validation, the D22 precursor has been reducing data in real time using Mantid. D11 has also recently joined the development effort with very good results. On SHARPER, data reduced with Mantid is sent back to Nomad to improve visualisation and decision-making capabilities.

On D17, the first neutron reflectometry experiment with real-time data analysis inspired by machine learning has been completed. Users from Swansea University in Wales and the University of Tübingen (Germany) monitored the evolution of thin polymer layers under heating with the aim of improving the efficiency of organic photovoltaic materials. They combined automatic data reduction and real-time analysis using Reflectorch, a Python machine learning package developed at the University of Tübingen. This was made possible through close collaboration between the Instrument Control, Scientific Computing and IT services at the ILL.

Subcommittees of the ILL Scientific Council

Just a week after the end of 2025 reactor operations, in early November, the ILL welcomed on site the members of the subcommittees of the ILL Scientific Council responsible for assessing experiment proposals, as well as ILL Scientific Council itself.

In this round, 369 proposals were accepted, corresponding to 393 experiments and a total of 1539 days of neutrons (to be delivered in parallel by the over 40 instruments in ILL's instrument suite).

The next proposal submission deadline is 15 February 2026. As a reminder, this date concerns standard beam time access requests – specific access modes are available for fast access, namely DDT and EASY. More information can be found here.