Collimated Hard X Rays from Hybrid Laser and Plasma Wakefield Accelerators

We report a synergistic enhancement of betatron radiation based on the hybrid laser and plasma wakefield acceleration scheme. Quasi-phase-stable acceleration in an up-ramp plasma first generates GeV-energy electron beams that act as a drive beam for PWFA, which then further accelerates the witness beam to GeV energies, enhancing both photon energy and flux. With this scheme, an average flux exceeding 1014 photons/sr above 5 keV, an order of magnitude higher than the reported record, along with the critical energy 71 ± 8 keV, and a full width at half maximum divergence (6.1 ± 1.9) × (5.8 ± 1.6) mrad2 of betatron radiation were experimentally obtained, and quasi-three-dimensional particle-in-cell simulations were used to model the acceleration and radiation of the electrons in our experimental conditions, establishing a new paradigm for compact collimated hard X-ray sources.