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Free keywords:
Physics, Optics, physics.optics, Physics, Plasma Physics, physics.plasm-ph
MPINP:
Research group A. Di Piazza – Division C. H. Keitel
Abstract:
We report on the generation of a narrow divergence (θγ <2.5 mrad), multi-MeV (Emax≈18 MeV) and ultrahigh peak brilliance (>1.8×1020 photons s−1 mm−2 mrad−2 0.1% BW) γ-ray beam from the scattering of an ultrarelativistic laser-wakefield accelerated electron beam in the field of a relativistically intense laser (dimensionless amplitude a0≈2). The spectrum of the generated γ-ray beam is measured, with MeV resolution, seamlessly from 6 to 18 MeV, giving clear evidence of the onset of nonlinear relativistic Thomson scattering. To the best of our knowledge, this photon source has the highest peak brilliance in the multi-MeV regime ever reported in the literature.