The first batch of 48 series-production Quench Heater Discharge Power Supply (DQHDS) units, provided as an in-kind contribution by KEK, Japan, has just arrived at CERN. These units feature a new design developed by CERN for the HL-LHC upgrade and will operate together with the Coupling-Loss Induced Quench (CLIQ) systems to protect the HL-LHC inner triplet superconducting magnets. They feature higher discharge currents, improved reliability, enhanced monitoring capabilities, and robust personnel safety mechanisms. Besides ensuring the protection of the HL-LHC inner triplets at Interaction Points 1 and 5, the new-generation DQHDS units will also be used for the protection of the individually powered dipoles (IPDs) and quadrupole magnets (IPQs) during the HL-LHC era.
A final validation step for the DQHDS, working in conjunction with CLIQ and the Quench Detection System, will involve 52 units produced by CERN and already installed at CERN’s Inner Triplet (IT) String test facility. These tests will confirm the integration and joint performance of the full magnet protection scheme, which is essential for ensuring safe and reliable accelerator operation under the more demanding conditions of HL-LHC.
Figure 1: Testing of some of the first batch of 48 DQHDS produced by KEK, which arrived at CERN in May 2025. Florence Thompson / CERN
This initial batch received is currently undergoing acceptance testing. Its delivery is part of the collaboration between CERN and KEK, formalised through an addendum to the Memorandum of Understanding signed in January 2024. Under this agreement, KEK is responsible for producing and delivering a total of 630 DQHDS units according to CERN’s technical specifications. Production by the Japanese firm, NICHICON CORPORATION, is progressing very well, with 4 pre-series and 264 series units already completed to date, including the 48 now delivered to CERN. The series production started after the successful qualification of 4 pre-series units, that passed all functional and safety tests, confirming readiness for full-scale manufacturing.
KEK is closely monitoring the progress of production and keeps CERN regularly informed. Both partners work closely together to address any issues that may arise, with KEK implementing prompt solutions and CERN providing technical support when needed. This close and efficient collaboration ensures continued progress and compliance with CERN’s technical specifications. Units will continue to be delivered to CERN in batches of 48 every four weeks, requiring sustained coordination between all involved teams. The Japanese series production is expected to conclude by the end of 2025, with acceptance of all units foreseen by mid-2026.
Figure 2. DQHDS units in different stages of testing. Florence Thompson / CERN