Big European Bubble Chamber (BEBC), at the European particle physics laboratory (CERN). The bubble chamber has been filled with a hydrogen-neon mixture and exposed to a neutrino beam. The energy from collisions between neutrinos and neon nuclei and protons (hydrogen nuclei) has led to the formation of showers of electrons and anti-electrons (positrons). The spiral pattern of the particle tracks is caused by the electrons following a curved path through the magnetic field applied in such experiments. The spirals decrease in size as the electrons lose energy by emitting photons.