An all-optical Compton source for single-exposure x-ray imaging
Résumé
All-optical Compton sources are innovative, compact devices to produce high energy femtosecondX-rays. Here we present results on a single-pulse scheme that uses a plasma mirror to reflect thedrive beam of a laser plasma accelerator and to make it collide with the highly-relativistic electronsin its wake. The accelerator is operated in the self-injection regime, producing quasi-monoenergeticelectron beams of around 150 MeV peak energy. Scattering with the intense femtosecond laserpulse leads to the emission of a collimated high energy photon beam. Using continuum-attenuationfilters we measure significant signal content beyond 100 keV and with simulations we estimate a peakphoton energy of around 500 keV. The source divergence is about 13 mrad and the pointing stabilityis 7 mrad. We demonstrate that the photon yield from the source is sufficiently high to illuminatea centimeter-size sample placed 90 centimeters behind the source, thus obtaining radiographs in asingle shot.
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