The HL-LHC Project will culminate with the accomplishment of a very demanding installation phase during the Long Shutdown 3 (LS3). To assess the project’s readiness, a tracking process on the expected availability of equipment has been implemented. The careful follow-up of this installation schedule float plays an important role in the strategical decision-making process. It will be one of the main indicators to validate and launch the LHC de-installation activities mainly at IP1 and IP5.
Start of de-installation (the day after the last circulating beam of Run 3) is presently scheduled for the 17th November 2025. This will be a step of no return and, as it stands, not all necessary equipment is foreseen to be delivered and accepted at CERN by then.
The installation schedule float provides a measure of the time margin available between the ready-for-installation date and the planned installation date. The ready-for-installation date is derived from the date of equipment completion or delivery at CERN, then adding all the preparation activities (such as final tests and quality control) required to ready it for transportation to its installation slot. The planned installation date also accounts for the transport requirements and constraints that could be originated by the LHC tunnel conditions (i.e. sectors closed due to other activities etc.).
The first installation schedule float analysis was presented at the Cost & Schedule Review (CSR) 2023. Such analysis will be updated twice per year, one for internal use around June, and one at the end of September in preparation for the incoming CSR. This year, the June update will have a higher importance as it will be part of the data set to be presented to the LS3 Readiness Review (11-13th September 2024). This readiness review, mandated by CERN’s ATS management, will be organised and chaired by the LS3 Coordinator together with the LS3 Committee. It will assess the technical readiness, and determine resource availability (of CERN groups, support contracts, technical teams, etc.), for all the projects approved for LS3. A successful outcome of the review will provide a positive and sound assessment for the confirmation of an LS3 start.
The apex of the HL-LHC Project and its international collaboration will be the successful operation of this new high-luminosity version of the LHC. To reach this ambitious milestone, the complex and very demanding de-installation and installation phases will need to be successfully completed in the allocated time of LS3. The detailed preparation of these critical phases has started and, together with careful monitoring of equipment readiness, is among the key elements that will contribute to ending Run 3 with a high level of confidence in the successful execution of the HL installation program, in parallel with all other activities that will have to be completed during LS3.
