International collaborations play a very important role in the HL-LHC Project. The HL-LHC Collaboration Office continues to act as the link between institutes, work packages and CERN, and is available to provide support across the project.

Series production is today well underway for all existing collaborations. Progress with each of the collaborations is followed by regular Steering Committee meetings, with the aim of holding at least one meeting per year for each of the collaborations.

The Collaboration Office continues to update existing agreements and put in place new agreements.

Figure 1. The HL-LHC Collaboration Board during the 2024 HL-LHC Collaboration Meeting in Genoa, Italy. Florence Thompson / CERN

Since the previous newsletter, an amendment formalising the Steering Committee’s decision (made in January 2024) on the collaboration with CIEMAT has been concluded. This amendment clarifies the parties’ contributions to the pre-assembly of the MCBXFA and MCBXFB-type corrector magnets: the last two MCBXFB magnets (MCBXFB11 and MCBXFB12) and one MCBXFA magnet (MCBXFA6) will not be delivered in order to minimise the extra costs for CERN and CIEMAT.

In terms of new agreements, the collaboration with the Pakistan Atomic Energy Commission (PAEC) for the construction of shielding components for the ATLAS and CMS experiments at the HL-LHC is being formalised, and the corresponding agreement is being concluded.

In September 2024, the CERN Council decided to grant Japan Observer status with respect to the HL-LHC project for the duration of the construction and operation of the HL-LHC, thus recognising Japan’s substantial in-kind and cash contribution to the project which now also covers the full scope for the High Power RF and distribution system for the crab cavities. The agreement formalising the latter was concluded in early 2025.

In addition, an agreement was signed between CERN and Brazil for collaboration in the context of the HL-LHC, with the aim of junior personnel from the Centro Nacional de Pesquisa em Energia e Materiais (CNPEM) contributing initially to the Inner Triplet String vacuum system and beam loss monitors for the HL insertion regions.

Lars Jensen stepped down as HL-LHC Collaboration Officer in the summer of 2024 and was replaced by Emmanuel Tsesmelis.