Positron-Electron Tandem Ring Accelerator

The Positron-Electron Tandem Ring Accelerator (PETRA) was a collider facility at the German Electron Synchrotron (DESY) laboratory, completed in 1978. It was designed to collide beams of electrons and positrons at high energies, reaching up to 19 GeV per beam. This machine was instrumental in particle physics research, notably providing the first direct evidence for the existence of gluons, the particles that mediate the strong nuclear force. PETRA has since been repurposed as a pre-accelerator for DESY's Hadron-Electron Ring Accelerator (HERA). Colliders like PETRA are crucial for high-energy physics as they allow the full energy of the colliding particles to be converted into new particles, enabling the discovery of fundamental constituents of matter.123