Internship and Thesis at CERN

1. What made you decide to apply to CERN?

To be honest, after graduating from high school, I never thought I’d have anything to do with physics again. As a computer science student, it never even crossed my mind that there might be internships there for me. After all, CERN is a research center for particle physics and, at first glance, has nothing to do with what I’m studying. However, when I saw the job posting on the university’s website , I read it more out of curiosity than with any real intention of applying. But I quickly realized: This sounds exciting. I looked into it further and discovered that only a small part of the work at CERN involves pure physics. Much more important are the development and construction of facilities, detectors, accelerators, and magnets. The Technical Student Program promised that, as a student, I could work right there, so I decided to apply.

2. How did the application process go?

Thanks to the cooperation agreement between Karlsruhe University of Applied Sciences and CERN, the application process was quite straightforward. After uploading my documents to the online portal, I had an asynchronous interview with questions about myself and my interests. After a short wait, I then had direct conversations with potential teams, during which they explained their projects and my potential areas of responsibility to me.

3. What is an internship at CERN like?

I chose the HGCAL team. With the second phase of the LHC, the so-called “luminosity”—that is, the number of collisions—will increase from 40 to 140 per event. To handle this new volume, all detectors must also be upgraded accordingly. My team worked on upgrading a subdetector of the CMS experiment, which had played a decisive role in the discovery of the Higgs boson in 2012. More specifically, we worked on the High-Granularity Calorimeter, a detector that measures the energy of individual particles. My first day at CERN—which was also my first day on the job—began with a large welcome session featuring an opening speech and some icebreaker games, during which I got to know some of the roughly 80 other technical students participating that month. Immediately following the session, I headed to my workstation, where I met my supervisor and mentor, as well as the rest of my team, for the first time. During the lab tour, I also got a quick crash course in physics on the side, since my physics knowledge at that point was already three years out of date. Within the first day, the number of particles I was familiar with had at least tripled.

The task assigned to me was to develop control software for the initialization, parameterization, and operation of the detector’s readout chain. To this end, I worked closely with my supervisor to define the requirements, but I was largely independent in designing the software architecture. It was particularly positive that I wasn’t treated like an intern, but rather as a full-fledged team member with a great deal of responsibility. When it came to software, my opinion was regularly sought, and my suggestions were seriously considered. That was definitely something special.

The absolute highlight was the two beam tests: two-week phases during which our prototype was tested under real-world conditions in the particle beam. These tests are crucial for mass production and the allocation of research funding. Everyone pulled together during this time and was extra motivated. Seeing how the work of the past few months paid off was very satisfying.

4. I would choose to do an internship or write a thesis at CERN again in a heartbeat because…

• … life at CERN is great even outside of work. Even in the first few weeks, I found a close circle of friends among other technical and doctoral students. Together, we went hiking, climbing, or took trips to Geneva, Lausanne, and Annecy. The surroundings, with the Alpine mountain backdrop and Lake Geneva, are incredibly beautiful.
• … CERN organizes ski tours in the winter. From December through February, ski buses run every weekend to nearby resorts, and they even offer free ski lessons for beginners and advanced skiers.
• … there’s definitely never a dull moment at CERN, whether at work or in your free time.
• … the internship was a once-in-a-lifetime opportunity that I would repeat in a heartbeat if given the chance.

5. My Tips for Those Interested in an Internship or Thesis at CERN

• Prepare a littlefor the asynchronous interviews by learning about CERN and its mission. Don’t worry—they won’t test your knowledge of physics, but a little basic knowledge about CERN itself, the LHC, and what CERN stands for can’t hurt.
• Don’t let it throw you off if the application process takes longer than expected. I applied in October myself and didn’t receive an acceptance until February.

1. What motivated you to apply to CERN?

After completing my bachelor’s degree, it was clear to me: Before starting a master’s program, I wanted to have a unique, new experience—something that went beyond a traditional academic program. I had already learned about the HKA’s partnership with CERN while I was still a student, but I wasn’t able to secure an internship during my cooperative study program. Once I completed my bachelor’s degree, that restriction was lifted, and I seized the opportunity right away. For me, CERN has always been a fascinating place. A place where physics and technology come together at the absolute highest level. Just the idea that particles are sent through kilometer-long tunnels at nearly the speed of light to explore the fundamental building blocks of our universe completely captivated me. I really wanted to see what a place like that looks like from the inside and how people work there. The chance to be even a small part of it sounded incredibly exciting. And since I ’d been wanting to spend some time abroad after my bachelor’s anyway , the internship at CERN was just right for me.

2. How did the application process go?

The application for the Technical Student Program is multifaceted but well-structured. First, as part of the cooperation program, I prepared the required documents (resume, statement of purpose, transcript, letters of recommendation) together with Martina Link from the HKA. Her support was very helpful in this process. I then submitted my application through the official CERN portal in several fields of study, since I had diverse interests and didn’t want to commit to one right away.

After the Human Resources department reviewed the documents, I participated in an asynchronous video interview. I had to answer five questions—which were not disclosed in advance—within a short time frame and record my responses on video—a challenging but also exciting experience. Upon successfully completing this step, you are added to a candidate pool. Up to this point, applicants are reviewed solely by the HR department at CERN. From this point on, the individual research groups at CERN can view the profiles and select candidates. I was eventually invited to an individual technical interview, and after a pleasant and relaxed conversation, I received the offer, which I gladly accepted.

3. What is the internship process like at CERN?

On the first day, the internship begins with a group orientation session. This is where all the new technical students who are starting in the same cycle come together. In addition to an introduction to CERN and some organizational information, the real highlight, however, is getting to know the others. Everyone is new to the place, in a similar life situation, and shares an interest in science and technology—that creates an instant connection. The first friendships form right at this event and often last beyond the internship.

Afterward, we headed straight to the various departments. From that point on, the internship is different for every student, because the work students do at CERN is extremely diverse. From developing an improved cooling system for the particle accelerator, to software for controlling the magnets, to machine learning for analyzing the physics experiments. No two internships are alike.

I myself worked in a group that developed the Fast Beam Condition Monitor (FBCM): a new detector for determining the collision rate at the CMS experiment, one of the two major experiments at the Large Hadron Collider (LHC). This measurement is essential for calibrating many other detectors and is therefore of central importance.

During my internship, I was very fortunate to witness two so-called beam tests. A beam test is a week of intensive testing during which the new detector prototype was exposed to a high-energy particle beam (~15 GeV). My task was to program the data acquisition for these tests and to develop a framework for analysis. The goal was to compare different test conditions, identify physical effects, and draw conclusions about the detector’s efficiency and accuracy. In addition, I worked in the lab to reproduce certain effects found during the data analysis of our detector using a small radioactive source. Overall, I thoroughly enjoyed this work, in part because it bridged the gap between programming and experimental physics.

4. I would choose to do an internship or write a thesis at CERN again in a heartbeat because…

Looking back, my time at CERN was one of the best periods of my life so far. Three things made it special for me:

• The people: In just half a year, I formed friendships that might otherwise have taken years to develop. Nowhere else have I seen such a high concentration of motivated, open-minded, and impressive people as at CERN.
• The work: The opportunity to work at a place like CERN, with state-of-the-art technology in a global scientific environment, is simply unique. The work didn’t feel like work at all, but rather like a gathering of people tinkering away at a shared vision.
• The surroundings: The region around Geneva is beautiful. Lake Geneva, the nearby mountains, hiking trails in the summer, skiing in the winter. And thanks to the very good compensation, you can truly enjoy all of this.

5. My Tips for Those Interested in an Internship or Thesis Project at CERN

If you’re thinking about applying for an internship or a thesis project at CERN, I can only advise you: Go for it! It doesn’t matter whether you have a background in physics or another field, because CERN offers a wide range of opportunities, including in areas such as computer science, engineering, or even economics. Be open-minded and don’t be afraid to tackle topics you’re not yet familiar with. With a little curiosity and dedication , it can turn into an unforgettable experience—perhaps even the best of your life so far.