arXiv subjects

L. E. Bradley

Publications and source records attributed to L. E. Bradley.

2 recordsLinked to original sources

arXiv2025

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

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 $ε_γ\approx11$ 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.

physics.plasm-ph↗

arXiv2017

Signatures of quantum effects on radiation reaction in laser -- electron-beam collisions

Two signatures of quantum effects on radiation reaction in the collision of a ~GeV electron-beam with a high-intensity (>3x10^20W/cm^2) laser-pulse have been considered. We show that the decrease in the average energy of the electron-beam may be used to measure the Gaunt factor g for synchrotron emission. We derive an equation for the evolution of the variance in the energy of the electron-beam in the quantum regime, i.e. quantum efficiency parameter eta > 0.1$. We show that the evolution of the variance may be used as a direct measure of the quantum stochasticity of the radiation reaction and determine the parameter regime where this is observable. For example, stochastic emission results in a 25% increase in the standard deviation of the energy spectrum of a GeV electron beam, 1 fs after it collides with a laser pulse of intensity 10^21 W/cm^2. This effect should therefore be measurable using current high-intensity laser systems.

physics.plasm-ph↗