Magnetic mission of the Particle Physics Division

Bob Tschirhart

Bob Tschirhart, deputy head of the Particle Physics Division, wrote this column.

The Particle Physics Division is deep in magnetic successes and challenges. Our science goals call for MRI-medical-quality magnets as wide as a basketball court for the Muon g-2 experiment and magnets of unprecedented strength and size that must operate in harsh radiation environments for the Mu2e experiment.

After an intense campaign that culminated in June, the Muon g-2 team established a clear path to full performance and initially cooled the 50-foot-wide electromagnet ring down to the low temperatures required for superconductivity. In parallel, the Mu2e magnet teams are working closely with industry and have recently operated prototype magnets at high performance, which bodes well for this Fermilab-industry partnership. Kudos to the Muon g-2 and Mu2e teams, which span the expertise of the Accelerator, Particle Physics and Technical divisions, for commissioning and developing these amazing superconducting magnets!

Meanwhile at CERN, the Large Hadron Collider is back in operation at twice the collision energy of the first run, which discovered the Higgs boson. The Particle Physics Division is engaged in many aspects of the CMS experiment, and we are on the edge of our seats in anticipation of Run II. The early CMS commissioning data for Run II is looking great. The heart of the CMS detector is a large and very powerful superconducting magnet that is currently dealing with an infection of contaminants in the liquid helium, which is the life-blood of superconducting magnets. At these very low temperatures and high performance, even a tiny whiff of air is enough to cause a fever that hampers long-term operation of the magnet. CERN and CMS are working day and night to attack this contamination so that CMS and the worldwide program can optimally access the science promise of Run II.

Magnets here, magnets there. The future of particle physics worldwide depends on ultracold “cryogenic” science and technologies critical to magnets, accelerator systems for the LCLS-II project and the PIP-II initiative, and detectors for neutrino science and cosmic science. If you flip through college catalogs, you will find precious few offering degrees in cryogenic science and technologies. Fermilab has a responsibility to U.S. particle physics to mentor and train junior engineers and technical staff in the exciting discipline of cryogenic science and technology. We are fortunate to have excellent senior engineers and technologists labwide who can serve the community in this way.

Particle Physics Division research in CMS, cosmic surveys, cosmic dark matter searches, detector R&D, muon science and, yes, theoretical physics depends critically on continued excellence in cryogenic science and technologies. We must achieve this with constrained budgets in the context of the larger vision of a flagship neutrino program. We can achieve this through close collaboration throughout the laboratory, the U.S. program and the broader international community. Doing so will continue to grow the magnetic personality of Fermilab.