A Visit to CERN: Fast Particles, Deep Underground

Katherine Kornei in front of CERN's Compact Muon Solenoid CMS detector.jpg

by Dr. Katherine Kornei

An unseasonably late snowstorm was pummeling Geneva International Airport when I arrived in early April. I pulled my suitcase through snow, dusted off my knowledge of French from high school, and rode tram #18 to its endpoint, a stop simply labeled “CERN.”

I had traveled over 8,000 kilometers to one of the world’s foremost physics research facilities. The European Council for Nuclear Research—the French translation, Conseil Européen pour la Recherche Nucléaire, is the origin of its acronym—was founded in 1954. Perhaps most well known for the 2012 discovery of the Higgs boson, the sprawling campus spanning two countries is justifiably famous.  

CERN Compact Muon Solenoid. Photo: Eetwartti, creativecommons.org

A Close Up View

It’s here that beams of subatomic particles zip through the Large Hadron Collider, a subterranean, circular particle accelerator that’s 27 kilometers in circumference (the planet’s largest). But no particles were colliding the day I visited—the Large Hadron Collider is shut down until 2021 for upgrades. As a result, I had the rare opportunity to go deep underground for a close-up view of the accelerator and its instruments.

I donned a bright orange hard hat before entering a large elevator with CERN researchers. After rapidly descending roughly 100 meters below Cessy, France, we walked onto a catwalk painted green. Directly ahead of us loomed the Compact Muon Solenoid, a 14,000-tonne particle detector that’s one of the four instruments that make up the Large Hadron Collider. When beams of particles—most often protons—are forced to collide in the Compact Muon Solenoid, its detectors record evidence of the smash-ups. On the day that I visited, the 15 separate sections of the Compact Muon Solenoid were splayed apart so technicians working on scaffolding could access the kilometers of cables snaking through the detector.

After taking a few pictures, we returned to ground level and blinked in the bright sunlight. I have a newfound appreciation for the enormity of CERN’s instruments and also the human power—physicists, engineers, and programmers—necessary to keep them running.

Compact Muon Solenoid Cutaway by Tai Sakuma, https://cds.cern.ch/record/2665537/