CMS: design, construction, operations

Steve Nahn

Steve Nahn, U.S. CMS detector upgrade project manager, wrote this column.

It’s a very busy and sometimes hectic place on Wilson Hall’s 10th and 11th floors these days working on CMS. Rather than progressing sequentially through design, construction and operations phases of the CMS detector upgrades, we are going through all three simultaneously. This leads to a certain amount of jumping around.

The design component addresses the high-luminosity LHC era commencing in the mid-2020s, at which time the LHC’s total luminosity will increase 10-fold. To exploit the physics opportunities afforded by the more intense beam while coping with increased radiation dose, we must replace or upgrade key components of the detector. A large fraction of the collaboration spent the summer studying what sort of detector we would need in that demanding environment. The result, a 300-plus-page technical proposal, is nearly ready for release, and R&D efforts at Fermilab and collaborating institutes are already framing the technologies needed to make these Phase 2 upgrades a reality.

The construction component, the Phase 1 Upgrade Project, is a set of strategically targeted upgrades to cope with the imminent increased instantaneous luminosity starting next year and continually growing up to the high-luminosity LHC era. The design for this phase is complete, and the job at hand is to build the new sensors, back-end electronics and online triggering system. This project just went through Critical Decision 2 and 3 reviews simultaneously. The conclusion was a resounding recommendation for approval after a few technical details are resolved. The approval, which we hope will come through in November, will allow us to transition into production mode, launching activities at SiDet, Wilson Hall and the Feynman Center at Fermilab, as well as at the 30 collaborating U.S. universities, to move the project from design to installation in the next few years.

Lest we forget, there is the ongoing, operating experiment, perhaps the most exciting of the three phases. The LHC is poised to restart in spring 2015, after a two-year shutdown at twice the center-of-mass energy, the last significant step foreseen. The low mass of the Higgs argues for new physics that may appear in the next run, and the collaboration is gearing up to find it. This involves a program of extended running of the entire detector with cosmic rays before the beam returns to bring the detector back to peak efficiency, computing challenges to make sure the offline data production is ready, and increased effort on the analysis chain, particularly for potential early high-profile discoveries. A new discovery in 2015 would be fantastic, full stop, and we are committed to ensuring we are ready for such an opportunity.

There is indeed a lot of exciting work going on. And amid all this, there’s still one more thing to mention: Our fearless leader Patty McBride is transitioning from U.S. CMS program manager into her role as head of the Particle Physics Division. We know she isn’t going far — only three floors down in Wilson Hall — but we’ll miss her anyway. We take this opportunity to give her a giant "thank you" for her leadership and tireless efforts up here on the 11th floor. PPD is lucky!

The operations phase of LHC Run II is only months away.