Beamline for Schools (BL4S) is a physics competition organized by CERN, DESY and the University of Bonn’s ELSA accelerator. Secondary-school teams propose an experiment they would like to carry out at a particle accelerator. The five winning teams are invited to work with scientists at the facilities. The historical 2026 edition received 712 proposals from 4,501 students in 89 countries; those winning experiments took place in August 2026. All team members submitting a complete, valid proposal receive a participation certificate.
For 2027, proposal submission begins in December 2026 and closes March 12, 2027 at 23:59 CET (Geneva time). The exact opening day is not stated. Winners are notified in summer and invited for approximately two weeks of experiments in late September 2027. Exact visit dates are not yet published; the August schedule belongs to the previous edition. Optional online events begin in November 2026, and newsletter subscription is not a required application.
Participation is free. The winning-team prize covers travel, accommodation and meals for up to nine students and two adult coaches; at least five team members are needed to win the trip. Students younger than 16 can participate anonymously or with parental data-processing consent, but only students aged 16 or above at the visit may travel. The 2027 invitation requires secondary-school enrollment in academic year 2026–27, while the FAQ also mentions the gap between school and university; that eligibility wording is not uniform.
Checked November 4, 2026 using the official homepage, submission guidance, 2027 invitation, terms and FAQ.