Following through on the current P5 priorities, the HL LHC CMS Detector Upgrade Project recently took a significant step forward with the completion of the independent project review supporting Critical Decision 2 (or CD-2; “baselining”), with a significant component of scope under review for Critical Decision 3c (or CD-3; “ready for fabrication”) approval. The in-person review was held at Fermilab, Jan. 24-27, 2023.

Many but not all project team members and supporting cast from the international CMS management during the CD-2/3c IPR at Fermilab. Photo: Ryan Postel, Fermilab
The $200M U.S. Department of Energy portion of the CMS upgrade consists of several new components, enhancing the detector capabilities for tracking, calorimetry, timing and triggering, to cope with the increased intensity of the LHC beam, starting in 2029. Since the previous major review in October of 2019, the project, with participants from more than 50 U.S. institutes as well as Fermilab, has had to navigate many complicated issues, including COVID, the consequent supply chain disruptions and heightened inflation, as well as the war in Europe, with direct consequences on this inherently international endeavor.
The success of the review can be directly attributed to the hard work not only of the scientists, but also the technicians, engineers, computing professionals, post docs, grad students and project staff, both at Fermilab (SiDet, Wilson Hall, MAB, Lab 5, FCC), as well as their counterparts at the many U.S. CMS institutes. The positive feedback from the review panel closeout confirms the successful completion of this stage of the project.
Full approval for production on the remaining scope is expected by the end of this calendar year.
Steve Nahn is the head of the CMS Detector Upgrades Upgrade Project for US CMS.
CMS department communications are coordinated by Fermilab scientist Pushpa Bhat.