High brightness multi-MeV photon source driven by a petawatt-scale laser wakefield accelerator

TL;DR

This paper demonstrates a high-brightness, multi-MeV gamma-ray source driven by a petawatt laser wakefield accelerator, achieving unprecedented photon flux and spectral brightness for potential applications in physics and nuclear science.

Contribution

The study provides the first experimental demonstration of a multi-MeV gamma source with significantly higher brightness than previous all-optical sources, using inverse Compton scattering with a laser wakefield accelerated electron beam.

Findings

Generated over 10^9 photons above 1 MeV per pulse.

Achieved peak spectral brightness of approximately 4×10^22 photons/mm²/mrad²/s/0.1%BW.

Performance matches a simple predictive model, guiding future enhancements.

Abstract

We present an experimental demonstration of a bright multi-MeV gamma source driven by a petawatt laser. The source generates on average $(1.2\pm0.6)\times10^9$ photons above 1 MeV per pulse, exceeding those of previous all-optical sources by a hundred times, and reached a peak spectral brightness of $(3.9 \pm 1.5)\times 10^{22}$ photons/mm$^2$/mrad$^2$/s/0.1%BW at $\epsilon_\gamma\approx11$ MeV. The source was produced by inverse Compton scattering of a laser wakefield accelerated GeV electron beam and its back-reflected driving laser pulse. Its performance is well described by a simple model of the laser and electron properties at the collision point that allows quantitative predictions and identifies clear strategies to further enhance radiation efficiency. Our results highlight the promise of this source for fundamental physics studies, as well as for applications of nuclear resonance fluorescence and nuclear transmutation.