Complementing its contributions to the JT-60SA and ITER fusion reactors, Fusion for Energy contributes to the R&D for material characterization facilities. Under the Broader Approach agreement, Europe and Japan are developing the Linear IFMIF Prototype Accelerator (LIPAc) in Japan, a deuteron accelerator demonstrator producing neutrons by nuclear stripping reactions on a liquid lithium target, part of the International Fusion Materials Irradiation Facility (IFMIF) project. In 2024, LIPAC prepared for the installation of the SRF cryomodule, concluding its construction. As first prototype, the cryomodule assembly faced challenges at various stages. Started in March 2019, the assembly was paused during its cleanroom phase due to quality issues with the superconducting solenoids, resuming in Aug. 2022. Further issues delayed the completion of the cleanroom activities until Sept. 2024. In 2024, the cryomodule assembly progressed at a good rate. The clean room worked concluded in Sept. and by late 2024 the cold mass was ready for insertion into the vacuum vessel, with transfer to the vault planned for early 2025. In this paper, we will outline the critical steps of this assembly process.

Plasma treatment has proven effective in recovering and reducing field emission in the affected superconducting radiofrequency (SRF) cavities. A joint effort is underway between CEA, ESS and INFN to apply this technique to the treatment of elliptical cavities in the ESS linac. This paper presents the work done so far, which aims at both the development of the plasma process for cavities in the cryomodule and the treatment of cavities in the vertical test configuration. The peculiarity of ESS cavities compared with typical cavities at 1.3 GHz is the absence of couplers for higher orders.

The installation phase of the European Spallation Source (ESS) linear accelerator is nearly complete. As with other superconducting linacs operating in pulse mode, LLRF systems play a crucial role in controlling accelerating beam parameters. Modern LLRF systems go beyond providing fast and reliable feedback for RF signal regulation; they also ensure precise, dynamic cavity tuning. Additionally, they enhance machine availability by monitoring various signals to identify potential issues and implementing fast and slow algorithms to optimize cavity performance within safety limits, tailored to specific accelerator conditions. Preparation for these tasks begins during cryomodule and cavity testing, prior to tunnel installation. Key parameters such as Lorentz force detuning coefficients, piezotuner range and polarity, main mechanical cavity modes, Pi-mode frequencies, slow tuner sensitivity, and backlash must be accurately determined to enable peak LLRF performance. This paper outlines the development, implementation, and application of software tools designed to determine these parameters for cavities tested at ESS Test Stand 2 (TS2) and those installed in the accelerator tunnel.

This paper presents the strategy for the simultaneous cryogenic operation of the ESS superconducting linac, consisting of 43 cryomodules. It details the process logic required for different operational phases and introduces a novel control system designed to manage these complexities. Key features of the system are discussed, including multiple independent automatic control sequences, a master controller for system synchronization, failure response protocols, and operator interface design. Fully deployed in December 2024, the system played a critical role in the successful cooldown of the accelerator. The paper also addresses lessons learned during this deployment and outlines potential improvements for future operations.

This paper presents the first operational experience of the European Spallation Source (ESS) cryomodules in a linac configuration, with a focus on the challenges encountered during the initial integrated cooldown and subsequent stable operation. Key aspects such as thermal stability, cryogenic performance, and system integration are discussed in detail. The paper also highlights lessons learned during the operation, identifies areas for improvement, and proposes strategies for optimizing cryogenic operations in the upcoming phases of the ESS project.

The proposed Future Circular Collider (FCC) integrated programme consists of two stages: an electron–positron collider serving as a Higgs-boson, electroweak and top-quark factory,followed by a proton–proton collider operating at a collision energy around 100 TeV. In 2021, in response to the 2020 update of the European Strategy for Particle Physics, the CERN Council initiated the FCC Feasibility Study. This study covered, inter alia, physics objectives and potential, geology, civil engineering, technical infrastructure, territorial implementation, environmental aspects, R&D needs for the accelerators and detectors, socio-economic benefits, and cost. The FCC Feasibility Study was completed on 31 March 2025. We present a few key results along with accelerator R&D goals and discuss the next steps.