In November, ESS suffered a brief disruption to its incoming power. Most of the equipment reacted as expected, except for one critical component of the ESS target station – an innovative system that will be the first of its kind for neutron sources.
The power disruption caused damage to the moderator, the component of the target that slows down the neutrons as they come off the target wheel, bringing them to the right energy for the instruments. The damage requires in-depth analysis to determine the most feasible way forward for the moderator system, which may include the installation, towards the end of 2026, of the replacement moderator currently being manufactured by ESS partners.
Helmut Schober, ESS Director-General, describes the situation, “These disruptions are a setback, undoubtedly. They will affect progress towards our Beam on Target (BoT) milestone. We will replan the work to limit the impact on the overall progress of the project. Building on the expertise and experience at ESS and in our partners, we will seize all opportunities to strengthen the overall operational readiness of the facility in view of the upcoming scientific activity.”
Teams across ESS and partners are working on establishing, by early 2026, a new timeline for ESS’s road towards science. ESS is also preparing a thorough technical analysis, with an external independent partner, to fully understand the chain of events following the outage.