Charge-neutral, GeV-scale electron-positron pair beams produced using bremsstrahlung gamma rays
Youhwan Noh, Jaehyun Song, Mohammad Mirzaie, Calin Ioan Hojbota, H. Kim, Seongmin Lee, Junho Won, Hoon Song, Chiwan Song, Chang‐Mo Ryu, Chang Hee Nam, Woo‐Suk Bang
Abstract
Abstract Matter-antimatter plasmas, such as electron-positron pair plasmas, are frequently observed in various astrophysical phenomena. In laboratory settings, electron-positron pairs have often been generated using high-Z converters irradiated by either direct laser pulses or laser-driven electron beams. Here we generate charge-neutral electron-positron beams with energies in the GeV range, utilizing bremsstrahlung gamma rays. Specifically, intense high-energy gamma rays produced electron-positron pair particles in a lead converter via the Bethe-Heitler process. The produced pair beams exhibited neutrality across all converter thicknesses throughout the energy spectrum spanning from 10 MeV to 1.8 GeV. Pairs with energies surpassing 1 GeV constituted up to 26% of the total kinetic energy within the spectrum. The experimental results were in good agreement with our Geant4 Monte Carlo simulations. These GeV-scale neutral pair particle beams have potential applications for understanding energetic astrophysical phenomena and high-energy particle physics.