I was in the passenger seat – a tech student writing my master’s thesis on supplying electrical power to superconducting magnets. Georg was driving and having a lot of fun. He is one of the few Estonians working on-site and is doing something similar to Google Street View, but in various tunnels at CERN.

The idea to intern at the European Organization for Nuclear Research (CERN) for a year came to me already in high school, but it became a tangible reality in the final year of my bachelor’s degree when our integrated technologies program manager Tauno Otto forwarded the CERN newsletter for students. A 12-month technical student contract was the most suitable for me because learning plays a major role in this position, and it is also possible to work on a thesis. At the same time, this period is long enough to be useful to the organization.

I was accepted to CERN during my master's studies in sustainable energy, on my fourth attempt. This is partly due to their selection process — they choose the candidate who best fits the project. Usually, you don’t know the exact projects when applying, so persistence is key. I received an offer from the CERN cryolab, where new low-temperature technologies are developed and tested, and ultra-cold measurements are performed. The multidisciplinary approach of cryogenics suited my integrated technologies bachelor’s and sustainable energy master’s degrees well. I was extremely excited to experience CERN’s complex, highly specialized, and almost futuristic environment. 

And all of that was true. Sure, some buildings and corridors were a bit worn out, but it’s what’s inside that matters, and CERN is probably the place with the highest concentration of experts on Earth. With just a few emails, you can find someone who can answer any technical question you have. For example, my supervisor Torsten held a Wednesday morning seminar covering topics from cryostat and detector construction to solid-state physics, culminating in his favorite subject — how to insulate your house. The cryolab section was relatively small, with about twenty people, but diverse in nationality and tasks. Besides me, there were two other engineering students, Luis and Chiara, working on measuring the lateral thermal conductivity of HTS tape and the mechanical design of one FCC detector. We all wrote our theses there.

Writing the thesis was very diverse. The first step was modeling. I translated an axisymmetric counterflow heat exchanger model done in MATLAB by a Latvian PhD student into Python. I added resistive heating, additional sections, and an optimization layer. Modeling turned out to be the most complex part of the process because there was no clear and definite path to the right solution, but growth isn’t always comfortable. Additionally, we had to determine the feasibility of constructing the current lead. The most challenging part was making the two flow channels leak-tight, which required epoxy resin adhesive tests. Experimentally, we also had to measure the radial thermal conductivity of the rolled copper mesh inside the current lead, and I was able to build this test almost entirely by myself, with some help from French technicians. Unfortunately, the measuring device assembly melted when the cryocooler helium compressor stopped working overnight due to high pressure, but the roughly one-kilowatt heater did not. Another learning experience. But the thesis was completed, and the rolled metal mesh structure has potential in current lead construction! My second supervisor, Patricia, currently recommends it for the SHiP spectrometer magnet.

Parallel to my daily work, guided tours were undoubtedly the best way to learn about CERN. I completed training for all six different visitor points on the Meyrin campus, as well as the liquid nitrogen demonstration in the cryolab. It was during these tours that clearly explaining complex ideas and answering questions proved to be the most rewarding and educational for me. Introducing my physics teacher mother to the antimatter factory and seeing the sparkle in her eyes at the street names (like the intersection of Route Pauli and Route Einstein) was very, very special. 

Last year, CERN celebrated its 70th anniversary with lecture series, concerts, and exhibitions. It was very fitting that at that time Estonia became a full member of CERN, which now gives Estonians an even better opportunity to participate in the organization's activities. On this occasion, together with local Estonians and President Alar Karis, we discussed the present and future and saw the Estonian flag raised on the Particle Square, equal to the other member states.

Workdays at CERN are rather long, but alongside that there is always plenty of socializing. I found a colorful group of friends there with whom we explored Geneva’s excellent modern art and music and theater scenes. In winter, the best ski resorts in the Alps are just a one-and-a-half-hour bus ride away, and in summer, you can sit by the banks of the Rhône River, which starts from the crystal-clear waters of Lake Geneva, and watch life (and people commuting to or from work) float by. The whole region has more hiking trails than one can walk in a lifetime, and mountain villages are just a pleasant train ride away.

After all of this, leaving was of course sad, but hopefully I will get back there someday. You should go too! The CERN visitor center is world-class. And you can even stay longer – for that, I wish you big thinking and dreaming! 

The article was published in the Tallinn University of Technology magazine Mente et Manu.