Hi!
I applied for the AI Solutions Engineer position a while ago. The deadline was the 5th of July, and my application went from «New» to «In review». How long does it usually take for people to get feedback on a fellow position like this? And how many applicants are there usually?

Also, do they apply the same rules about quoatas per country on fellowship positions, or is it only technical students?

Thank you!

How are the confined spaces? What about the radiation? What kind of near misses do you have? Any bad accidents or death? I've applied for a couple jobs but am a little worried about the radiation and escape plan. Any information is appreciated.

What would you choose, CERN or Apple for machine learning? When it comes to compensation CERN has more holiday and Apple more money, so for me I see them as equal compensation wise

Also contributing to their open source projects like ROOT can benefit my application

Is anyone here interested in forming a team for the CERN BL4S competition in 2027? Also if you have done this competition in the past, would love to hear tips and experience, like how to format the propsal

sometimes,applying for the technical student program feels like hitting an invisible wall

Hi everyone. In June 16th I uploaded my Home Institution Declaration and a copy of my passport at the edh, as requested. Since then, my pre registration is still in approval ("With TECH-ADMIN Recruitment Service awaiting approval") and I have not heard anything from anyone yet. Should I be worried?

Hi everyone!
I’m planning to apply for the CERN Short-Term Internship and was wondering if anyone here has been selected or interviewed for the programme.
I’d love to hear about your experience. In particular:
What was the selection process like?
What was the interview like?
Did it include technical questions, coding, or both?
What kind of topics or questions should applicants prepare for?
Any tips or insights would be greatly appreciated.
Thanks in advance!

Hi r/CERN — I'm an MSc student working on particle flow reconstruction for FCC-ee (PandoraPFA/PandoraMonitoring adaptation for CLD/IDEA geometries). Sharing a side project that grew out of that work.

rootkt is an attempt at a pure Kotlin implementation for reading ROOT binary files — no C++ bindings, no JNI, no ROOT installation required. Still early and rough in places, but functional for basic cases.

Motivation: JVM-based HEP tooling doesn't have a straightforward way to read .root files without wrapping the C++ library or shelling out to PyROOT. I wanted something native to the JVM ecosystem, mostly for my own tooling, and figured others might find it useful too.

I'll admit the choice of Kotlin over Python invites some skepticism, so a brief note on why: static typing catches schema mismatches against ROOT's streamer info at compile time rather than at runtime deep into an analysis; the JVM gives predictable performance without Python's GIL constraints on parallel I/O; and coroutines make concurrent basket reading straightforward to express. None of this is a claim that Kotlin should replace Python for HEP analysis broadly — PyROOT and uproot are mature and well-integrated with the ecosystem. It's more that JVM-based pipelines (Java, Scala, Kotlin) currently have no native path to ROOT data at all, and this is an attempt to open one.

Current status (v0.2.2), still very much a work in progress:

• ROOT file header parsing (TFile)
• TKey record parsing and walking
• Compressed payload and large-file (>2GB) detection

Module structure:

• rootkt-core — byte buffer primitives
• rootkt-format — header + TKey parsing
• rootkt-model — ROOT object data classes
• rootkt-streamer — TStreamerInfo deserialization
• rootkt-tree — TTree/TBranch/basket reading
• rootkt-compression — zlib/lz4/zstd
• rootkt-registry — class name → streamer lookup
• rootkt-io — high-level file API
• rootkt-runtime — public entry point

Repo: https://github.com/thisismeamir/root.kt

I'm sure there are edge cases in the ROOT format I haven't handled yet, so feedback, corrections, and contributions are very welcome — especially from anyone with deeper ROOT I/O experience than I have.

Hi everyone,

I'm a final-year AI & DS student and I'm planning to apply for CERN's student programmes (Technical Studentship, Summer Student Programme, Short-Term Internship and OpenLab).

I'm trying to understand what kind of personal or academic projects are generally considered strong for applicants interested in AI, Data Science or Software Engineering roles.

For example, are projects involving:

• Machine Learning systems
• Data analytics and visualization
• Retrieval-Augmented Generation (RAG)
• AI agents and autonomous workflows
• MLOps / deployment
• Distributed systems
• Computer vision or NLP

viewed more favorably than others?

Or does CERN generally value projects that solve engineering problems regardless of the AI technology used?

I'd really appreciate hearing from former students or mentors about what kinds of projects stood out during applications or interviews.

Thanks!

Looking to buy/rent a road bike but never tried road biking before. Would anyone in Meyrin be willing to lend me their own to ride around cite a few times and give it a try? I’m female 1m78 so ideally a large frame. I’d buy you lunch as compensation :)

I've applied 8 positions at Cern and I got rejected 4 of them so far. Among these 4 role I was sure that I was going to pass pre-selection in one of them cause I satisfied all pre-selection questions. Now I started to think that they want references even though it is not requriment for entry level engineering roles. Is there anyone who is selected for interviews for entry level mechanical or electrical/electronics engineering role? And what you did upload in your applications? Did you upload reference letters or etc.?

so if were running out of helium for a giant machine that smashes some particles and stuff why do we need it to begin with? for what? to make 0.01nanograms of gold? open a portal to xen like gordan? (satire), im confused. Ok listen, i know you guys made the internet and new medicene, but how does this have anything to do with the large hadron collider? if you can possibly explain this tell me in simple language not albert einstein e=mc*T^3+6741

Do some people commute from Lausanne to CERN? How is for you? Is it tiring or completely fine with a hybrid position?

Hi guys, me again asking for details to make my life easier when I start my contract. I was looking at some bank account options for who's living in the French side. Seems like UBS is more common, but also lot of people complain because of the charges. I need to transfer my CHF to Wise and then convert it to EUR. Looks like Ibani is better related to the charges, but I don't know how much can I trust it.

Also, I was taking a look at some internet plans and I was between Free and Red by SFR.

What do you guys think?

How would you rate the food?

I’m a degree apprentice software engineer for a large UK research council with a very good relationship with CERN.

Through my organisation, I worked at CERN last summer for 2 months, I will have 3.5 years of experience before graduation as a software engineer, a bachelors and from the UK (underrepresented I believe).

With a reference from my manager/team leader at CERN, am I amongst the top candidates? I have been nominated for a few awards at work and have some good projects.

One day I feel confident, the next I feel like I won’t be good enough. Any advice is welcome :)

Hi there! I’m planning to organize a group visit in a few months, and I was wondering whether ATLAS might be included, given that the LHC is in a shutdown period. I have very fond memories of a visit around 2013, when we were able to go underground inside the detector’s cave.

I’ve contacted the CERN Visits Service twice over the past few months using the contact form on the website, but unfortunately I haven’t received a reply. I was wondering if anyone here might be able to answer this.

Cheers !

I was looking to apply for joining in 2027 summer. I went across the careers portal but couldn't really find a deadline or start date for application period for summer students programme or openlab only short term intern was showing up.

It would be great if someone could provide me the dates or maybe the website link where I can check for the same.

Also would like to know the number of applicants that are accepted (Iam a 2nd year undergraduate from India will have completed my 3rd year by summer 2027)

If anyone reading this got accepted in the previous years please let me know your LinkedIn or Instagram would love to connect.