Nihal Brahimi in front of The Globe of Science and Innovation visitor centre
CERN alumna: Nihal Brahimi
At CERN: CERN Summer Student 2014
Today: Post doctoral researcher in ATLAS

OAR: When did you come to CERN as a Summer Student and what did you work on?

I came to CERN as a summer student in June 2014. I did my two-months internship within the AEgIS group, which designed an experiment that would allow probing the gravitational interaction in a matter-antimatter system in order to shed some light on the matter-antimatter asymmetry riddle. Eventually, this would be achieved by producing a beam of antihydrogen atoms, using antiprotons delivered by the Antiproton Decelerator (AD) at CERN, dropping them and measuring how fast they fall with high precision detectors. Understanding the response of these detectors to antimatter and improving the detection methods of matter-antimatter annihilation vertices at low energies is one of the key ingredients of this experiment. This is why, building a secondary beamline enabling to cool down antiprotons coming from the AD to a few keV and studying their interactions with high precision detectors was proposed by the group. In this context, my task was to follow-up on the work of technical students within the group that started developing a simulation of the beamline based on the GEANT4 toolkit in order to study the feasibility of its construction. In particular, I optimized the parameters of the setup in order to have a beam of low energy antiprotons with the highest flux and lowest angular dispersion achievable downstream of the beamline, right before interacting with the detectors.

Nihal Brahimi, bottom row, second from the left, AEgIS group

OAR: What is your best memory of working at CERN?

It is very hard to pinpoint a single memory as being the best, because almost every day (and I promise I am not exaggerating) during my two months internship brought its own wonderful memories and exciting moments that I still cherish and ruminate over until this day. Among my best memories is meeting and becoming friends with other summer students who came from all four corners of the world, which made our established tradition of having potluck dinners at the kitchen of building 39 all the more lively and enriching. We literally never ran out of topics to discuss, from our different summer projects, plans to discover the city of Geneva and its outskirts and surely enough our different cultural background, to which we were not exposed to before. Actually, I am still in contact with my CERN friends, I even had the chance to see some of them again, and it always felt like no time has passed and we could just pick up right from where we left off at our dinner gatherings.

Potluck dinner

OAR: What are you currently doing and where are you located?

I am currently a post-doctoral researcher (since March 2020) affiliated with the Tsung Dao Lee institute and the Jiao Tong University in Shanghai, but mostly based at CERN. I am working within the ATLAS group of the institute, which is involved in a variety of projects such as carrying out precision measurements in the Higgs boson and Top quark sectors.

OAR: What skills did you develop during your CERN Summer Student experience which have been particularly useful in your subsequent career trajectory?

Being a summer student at CERN was my first ever experience of working in an international group of researchers which was the perfect atmosphere to start developing the skill of communicating and discussing one's results as well as identifying the next steps to undertake to converge on the studies. On the other hand, I had limited programming experience prior to the internship but working on the summer project allowed me to sharpen my programming skills namely in the Object Oriented model through the use of tools such as ROOT for data analysis and GEANT4 for simulating the passage of particles through matter. Additionally, the rich program of summer lectures, visits to the main CERN experiments and organized hands-on workshops were invaluable in making the decision of pursuing a career in experimental particle physics.

OAR: What skills did you need to develop further when you left CERN to face your next challenge?

The summer internship at CERN already helped me lay a strong foundation for my subsequent challenges namely carrying out a Master in Particle Physics in Marseille (France) followed by a PhD thesis within the ATLAS group of the Centre of Particle Physics of Marseille (CPPM). Other than improving further my programming skills, I needed to develop scientific writing and presentations skills, which were crucial during my PhD thesis.

OAR: Would you recommend the CERN Summer Student programme to other people?

Without a shred of hesitation, YES! It is a life changing experience, the benefits of which I am still reaping to this day, both on the professional and personal levels.

Geneva outing

OAR: What advice would you give your younger self?

I have wanted to become part of the CERN scientific community ever since I heard about the organization and the LHC, from my high school physics teacher when I was 14. Basically, every choice I made since then was to get me closer to this goal and I am tremendously grateful that I got the chance to achieve it. So, the advice I would give my younger self cannot be better formulated than what Marie Curie said to her brother in their correspondence: "Life is not easy for any of us, but what of that? We must have perseverance and above all confidence in ourselves. We must believe that we are gifted in something, and that this thing, at whatever cost, must be attained".

OAR: Do you still follow up on what is going on at CERN?

Yes, absolutely. In addition to following CERN on the different social media outlets, my work grants me the opportunity of being exposed to the latest research results and developments being carried out by the various experiments at CERN.

Cloud chamber WS

OAR: In your opinion, what is the unique value of the CERN Alumni Network?

I believe that having a platform where all CERN Alumni can share their experiences and stay connected is extremely valuable especially for those that are at an early stage of their careers like myself. It is also inspiring to see, thanks to the events organized by the network, how the skills acquired at CERN can be transferable to other fields and not only applicable to academic research. Should someone ponder the possibility of transitioning out of Academia, having a channel to get in touch with the Alumni who have been through that change is immensely helpful.

OAR: What is your proudest achievement?

My proudest achievement so far is doing a thesis in experimental particle physics within one of the main LHC experiments, ATLAS. Looking back, I am very glad that I made the decision of leaving my comfort zone that is my home country, five years ago, and move abroad just to pursue my dream of becoming an experimental particle physicist. I would not have made that leap if it weren't for my positive experience as a CERN summer student.


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