November 1, 2023 was the day that our own Nergis Mavalvala, our Dean came to CERN for the first time. Bolek the director of the Laboratory for Nuclear Science had invited her and she accepted, curious as we learned during the visit because she had never been to CERN before. While the trip included a visit to the MIT folks from theory, the ISOLDE and LHCb groups, we prepared from the CMS side. We wanted to show Nergis what we are up to at CERN. While most other research groups at MIT can do their research on campus we are bound to CERN because there is only one accelerator in the world that collides protons or heavy ions at the highest energies, and that is the Large Hadron Collider, LHC. Our group and the individuals in our group have a long history with CERN and MIT has traditionally supported our efforts very well by appointing young enthusiastic faculty, supporting the employment of personnel at CERN, granting extra research leaves or allowing faculty even to teach remotely (2007) long before video conferencing and zoom was a thing.
For the CMS visit, Nergis arrived 4 minutes before scheduled at 13:26 and the round of introduction of the over 20 CMS folks that had arrived started our session. Nergis learned of all the important things our groups do at CERN to make the CMS experiment run smoothly, while we learned that Nergis works on the LIGO experiment another massive physics experiment and that one of her favorites is Squeezing Light..
After the introduction round and the explanations of the basic physics and detector projects, Jan Eysermans prepared us for our decent into the pit, about 100 m below the surface where the LHC brings hadrons to collision and the CMS collaboration has installed its huge experiment. On our way to the elevator we swung by the big computing room where the Storage Manager system, the very end of CMS DAQ is located. The PPC is the sole responsible for the this system including design, construction and operation since the very beginning of CMS data taking.
The hole, into which CMS had been lowered in December 2006, was actually open and we took a peek down the shaft which left us with an impression of the size of the experiment. It barely fit in the gigantic hole. We all picked up our obligatory helmets which are equipped with a location sensor to automatically account for the people going down into the highly controlled area through the pressurized elevator.
Due to the radiation environment, which had not yet been properly surveyed, we could not enter the Experimental Hal itselfl, but we visited the various stations in the Service Cavern. We looked at the front-end electronics and the slow control system, and took a picture where Nergis appears to be standing close to the large blue tubes carrying the beam and all relevant infrastructure in the LHC tunnel.
We had thorough explanation by Jan and great conversations about how the experiment works and how CMS makes sure everyone is safe while working in this unusual environment. Bolek mentioned that during his training he failed the oxygen mask test miserably. Masks are important because if a leak develops and the superfluid Helium, used to cool the superconducting LHC magnets, escapes the tunnel can quickly fill with inert gas which would lead to asphyxiation without oxygen mask. Accidents happened in the past and the mask without anyone in a danger zone but the masks would allow individuals to walk for long enough to get to safety.
After the CMS visit was finished, which was by the way spot on time at 15:00, Nergis continued to the LHCb experiment. We all met again for a dinner at 18:00 in Satigny to close out a wonderful day, full of physics and beyond physics conversations.