Luminescent materials can emit brighter light when hit by antimatter particles called positrons than when excited by the particles’ matter counterparts, electrons.
When charged particles bombard luminescent semiconductors, the semiconductors light up. This allows physicists to use these materials to keep track of particle beams in experiments. Eve Stenson and her colleagues at the Max Planck Institute for Plasma Physics in Garching, Germany, fired low-energy positron beams and electron beams at screens made of luminescent semiconductors. When the particles hit a screen, they excited the semiconductors’ electrons, producing light.
The team found that positron beams created as much light as did electron beams with hundreds of times more kinetic energy. The findings suggest that positrons annihilate on collision with particles in the semiconductor, causing the positrons to convert more of their energy into light than electrons do. The beams’ different behaviours could be used to probe the structure of luminescent materials, say the authors.