Dear HiLumi collaborators,
The period following the 9th Collaboration Meeting in Fermilab, 14-17 November 2019, has been exceptionally rich in events.
The most striking has certainly been the COVID-19 emergency, with long periods of lockdown almost everywhere. Although work has resumed at CERN and in most laboratories, the consequences go far beyond the lockdown time. Work has been slowed down by special safety procedures and by reduced physical presence in the laboratories. We are all striving to minimise the impact on the project, as discussed in various special “COVID-19 crisis” Project Meetings with external collaborators, and during the Technical Coordination Meetings that have taken place with a remote connection since March with an invitation to all collaboration institutes managers. At present, it is difficult to fully evaluate the impact in terms of costs and planning. A delay of about 4-6 months on the hardware deliverables is probably already accumulated (maybe not all due to COVID!), but more delays may accumulate if the situation does not improve in a stable way. It is only this autumn, probably at the 10th Collaboration Meeting, that it will be possible to make a more complete assessment.
However, many events with a significant impact on HiLumi occurred before and after the COVID-19 emergency. Many are covered in more detail in this Newsletter. Let us mention just a few of them:
The 4th Cost & Schedule Review. Chaired by N. Holtkamp (SLAC), a panel of renowned scientists and engineers from around the world, met at CERN from 11 to 13 November 2019 to examine the status of the HL-LHC and LIU projects. Regarding HiLumi, the main outcomes were:
- Endorsement of the extra cost of about 20 MCHF in the present scope. This was the result of an exceptional endeavour, which succeeded in mitigating a much higher extra-cost almost fully and by savings in all Work Packages (WPs). The continuous optimisation work was greatly appreciated by the Panel. The request for additional budget, which of course was presented in agreement with CERN Management, is now accounted for in the 2020 MTP (to be approved by CERN Council in September 2020).
- Endorsement of the increase of scope of the project, by inserting in the baseline: the hollow electron lens (WP5-Collimation), the crystal collimation for ions (WP5) and the new LHC beam dump system and additional dilution kicker (WP14). The new baseline with this new equipment is called Baseline 3.0.
- Endorsement of the project readiness for installation in a Long Shutdown 3 (LS3) in early 2024. Following a drill down session dedicated to the readiness of equipment for installation and to the preliminary installation plan presented by the project, the panel confirmed the readiness of the project with a one-year margin. The Panel also recommended carrying out a review of the installation plan, including all measures to possibly adapt it to the given LS3 timeframe (2.5 y at present).
The shift of the start of LS3 to the beginning of 2025. The CERN management, following a special meeting with the CERN Directorate, Projects (LIU and HL-LHC) and LHC experiments in November 2019, decided to extend Run3 over the entire 2024. This measure, requested by the LHC experiments to optimise the physics output, should not have an impact on the delivery of project equipment, except small schedule optimisation for cost and/or risk reduction. However, the COVID-19 emergency now requires another review of the project schedule, also in view of the recent decision of CERN (decided in agreement with the experiments in June 2020) to postpone the start of physics data taking in Run3 to February 2022. The baseline with LS3 starting in 2025 is called Baseline 4.0.
In December 2019, the successful test at nominal current of the first long IT quadrupole magnet, the MQXFA03, half of the Q1 or Q3 assembly by US-AUP, in the vertical test station of BNL.
The final complete validation of the HiLumi cold powering concept in June 2020: the Demo 2 system, featuring a 60-m long complete cable prototype with current leads and demonstrator cold boxes, successfully transported 20 kA in the main circuit and 7 kA in an auxiliary circuit at 20 K temperature in both directions, validating all aspects, including thermal contraction management and thermal load on the cryostat.
Further important news is described below: the end of the production of the special MoGr for low impedance collimators, the difficult experience with the 11 T dipole (and the issue found in the second series magnet S2). All these points will be discussed at the next collaboration meeting that will be held in a special form with remote connection because of the uncertain travel conditions due to COVID-19. The meeting will take place in the CERN main auditorium. It will be held by video, avoiding travel, which remains a serious difficulty in many countries, and especially between continents. We thank the collaborators of the University of Uppsala who were supposed to host this CM10, for agreeing to postpone the meeting of Uppsala to the autumn of 2021.
Finally, a personal word as former HL-LHC project leader. As you are all aware, on 1 July, I handed over the project leadership to Oliver Bruning, as established with our CERN Director for Accelerators and Technology, Frederick Bordry, in view of my retirement from CERN on 30 September 2020.
In 1995, when I was at the University and INFN of Milano, I started working on the LHC luminosity upgrade (as it was then called up until the High Luminosity LHC was established in 2010), by proposing a triplet quadrupole in Nb3Sn, of 300 T/m with the same 70mm aperture as the present LHC. It took years of study to refine the concept, eventually using the extra-field given by the Nb3Sn to increase the aperture, rather than increasing the gradient. Initially devised in two phases, the LHC Luminosity Upgrade was finally established as the HL-LHC project in 2010, following the famous Chamonix 2010 workshop and a series of LMC (LHC Machine Committee) meetings, as well as the proposal for the FP7-HiLumi LHC Design Study prepared in summer/autumn 2010.
Since then, the project has grown enormously: while the IT quadrupoles in Nb3Sn remain the cornerstone of the whole project, a variety of equipment and new cutting-edge technologies are now an essential part of the project. I am very proud to say that HLLHC is probably the most technological project in the accelerator domain. In all WPs, new substantial goals are planned to meet very demanding specifications. The project has grown to reach about 1 BCHF in CORE-cost with more than 2000 FTE-y of CERN staff (and some 500-600 FTE-y of staff in the collaborating institutes). It is a project based on international collaboration since its incipit. High Luminosity LHC is now well “en route” and the path is clear: however, the destination is still far away, storms may come, and adaptations may be necessary. Despite the challenges, I am certain that under the gifted leadership of Oliver, whom I want to thank wholeheartedly for all these years spent managing the project together, your commitment will lead the boat safely to its destination!
Buon Vento!