Beamline for Schools (BL4S) is a physics competition organized by CERN (Geneva), DESY (Hamburg), and the ELSA accelerator (University of Bonn) that gives high school students the opportunity to perform a real experiment at a particle accelerator beamline.
Teams submit written proposals describing an experiment they would like to carry out. Winning teams are flown to one of the three facilities to conduct their proposed experiment using professional-grade beamline equipment, supervised by physicists. The 2026 edition received 712 proposals from 4,501 students across 89 countries.
Competition structure:
- Proposal submission (closes ~March): Teams write and submit a scientific experiment proposal
- Shortlist announcement (~May): Several teams shortlisted; additional prizes awarded to shortlisted teams and those with the best outreach proposals and videos
- Winners announced (~June): Winning teams selected to travel
- Experiments at the accelerator (~August): Winning teams visit CERN, DESY, or ELSA to run their experiment
All eligible submissions receive a certificate of participation.