Proton Beams Without Borders

I could hear birds, cows, and the occasional passing car every morning when I woke up during my global co-op experience. Mornings were peaceful in this French village just outside of Geneva, Switzerland. This was also the case 100 meters underground, at least until early May. After that, proton beams with energies comparable to the USS Harry Truman travelling 13 miles per hour began to collide with each other 40 million times every second. While the relative silence in my room was interrupted by my alarm going off, not too far away protons were getting ripped to shreds in the hope of producing and detecting the building blocks of matter.

After two and a half years at Northeastern, I had finally made it to CERN, the world’s largest particle physics laboratory and where the Higgs Boson was discovered in 2012. I had first heard about it while taking the high school class that inspired me to major in Physics and to pursue a PhD in the field. This co-op opportunity was one of the reasons that I decided to attend Northeastern and one of the main things that I worked towards my first few years here.

The house that I lived and started my days in was owned by the US-based part of the Compact Muon Solenoid (CMS) collaboration. This collaboration runs one of the four massive experiments analyzing the results of the proton collisions happening in the Large Hadron Collider (LHC). This collaboration consists of nearly 4,000 scientists and engineers, including professors, technical staff, postdoctoral researchers, graduate students, and a handful of undergraduates. During my six months at the US-CMS house, I lived with many graduate students who came and went as well as some undergraduates who came to CERN as summer interns.

After leaving home in the morning, I would walk about six minutes to get picked up by a free shuttle that took me to Prevessin, one of CERN’s many worksites. There, my main project was building and testing prototypes of Cathode Strip Chambers (CSCs), one of the detectors used by CMS to detect muons. These chambers contain a gas mixture that includes CF4, which slows down chamber degradation caused by heavy radiation doses. Unfortunately, CF4 is also very expensive and a potent greenhouse gas. The prototypes I built were filled with different gas mixtures, irradiated, and periodically tested in an effort to find one with less or no CF4 that could still survive the radiation.

When there was not much to do at Prevessin, I could take another shuttle across the French-Swiss border to Meyrin, CERN’s main site. While there, I would eat lunch with the other two co-op students, work on other projects on my laptop, or attend seminars on a wide variety of topics. In the same auditorium where the Higgs discovery was announced, I listened to a Canadian astronaut describe her experience working and living on the ISS and a group of esteemed particle physicists discuss plans for the next generation of particle accelerators.

On the weekends, Geneva’s central location allowed me to travel in many different countries, including France, Switzerland, Germany, Italy, Ireland, the UK, Austria, the Netherlands, Spain, and Belgium. This was made even easier by the fact that my two Boston roommates were also co-oping in Europe at the time. One was doing cartilage engineering research in Zurich, Switzerland and the other was studying loneliness in elderly migrant populations in Cardiff, Wales.

Perhaps my most memorable weekend travel, though, was only a few kilometers by car and 100 meters down by elevator. During my second weekend at CERN, in mid-January, the LHC was still off for maintenance and one of the Northeastern group’s postdocs took me and the other co-ops down to see the CMS detector. It stands almost 50 feet high and weighs over 15,000 tons. Designing, building, and running it has taken a herculean effort by thousands of people over multiple decades and it left me completely in awe. This was a common feeling as I spent half a year living my dreams on co-op abroad.

This work was largely funded by National Science Foundation grants PHY-1120138, PHY-1624356, and PHY-1343486.

Jameson O’Reilly, Physics & Mathematics