First pp¯ collider interactions as seen by the streamer chamber of UA5 in April 1981 First pp¯ collider interactions as seen by the streamer chamber of UA5 in April 1981

Stereo views of a proton-antiproton collision photographed in the streamer of the UA5 collaboration at the CERN Collider in March. The Collider was then operating in the pulsed mode which enabled collisions to be observed up to world-record energies of 450 GeV per beam.