Breit-Wheeler Pair Production
The simplest process to create an electron-positron pair directly from the vacuum would require colliding two photons with an energy equivalent to the rest mass of the electron and positron (511keV each).
However, an experimentally more accessible path is via the so-called multiphoton Breit-Wheeler process. In this case, a high-energetic gamma photon of several GeV energy is collided with many photons of optical wavelength and the generated electron-positron pair can be separated and detected downstream of the interaction.
At CALA, the infrastructure exists to provide high-energetic gamma rays (converted from laser-accelerated electron bunches) and a synchronized high-intensity laser pulse (coupled out from the same driver laser). Together with the colleagues of the research unit, current experimental research focuses on creating a stable electron beam source for the generation of the gamma rays as well as implementing a detection scheme to detect the very low expected number of pairs created.
Research coordinator: Prof. Stefan Karsch