By Nicola Solieri and Gabriel Banks (CERN)
The Preliminary Design Review (PDR) for the High-Luminosity LHC (HL-LHC) external beam dumps (TDEs) was hosted at CERN on 11-12 March 2025. After two days involving 19 in-depth presentations, the international panel of reviewers confirmed that the project meets the objectives of the preliminary design and is well positioned to produce the new dumps for their installation during Long Shutdown 3 (LS3).
The panel praised the project’s rigorous systems engineering framework, which gave a clear definition of requirements for the subsystems, a careful management of interfaces, and a structured assessment of the most critical functional failure modes.
The finite element models developed by the team reproduce, with remarkable fidelity, the behaviour of the instrumented dumps in Run 3, giving strong confidence in the accuracy of the models for HL operation.
The HiRadMat-65-HLTDE in-beam experiment demonstrated the reproducibility of the intense thermal shocks that are achieved in the carbon-based core materials of the TDE in nominal and accidental scenarios. In these cases, temperature increases of up to 3000°C can occur in only 86 μs.
The successful prototyping of titanium grade 5 tubes, shrink-fitted with graphite blocks, also demonstrated that the proposed design is feasible to procure and assemble. On this point in particular, the panel provided useful recommendations for further studies to characterise the long-term resistance of the vessel’s titanium alloy. These studies are now underway, and the results are expected in the coming weeks.
Informed by the feedback from the review, the project is now transitioning into the detailed design phase. The first invitations to tender for the long-lead-time items will be launched in the coming two months.
The project team is grateful to the panel for the valuable recommendations and to the HL-LHC project office for their support in the organisation of the review.
HiRadMat-65 in-beam experiment
Previous news on consolidation of LS2 LHC beam dumps

Participants of the Review