Speaker
Description
We present the results achieved during the commissioning of the ELI Gammatron beamline, a femtosecond hard X-ray betatron source based on laser wakefield acceleration driven by the petawatt-class L3 laser system (10 J, 27 fs, 3.3 Hz) at ELI Beamlines. Leveraging the small pointing and energy fluctuations of the laser system, we have successfully demonstrated laser wakefield acceleration of shot-to-shot reproducible quasi-monoenergetic electron beams exceeding 1 GeV. Adjusting the position of the gas jet, we have found a regime of strong transverse electron oscillations and a stable betatron X-ray signal. A broadband synchrotron-like energy spectrum was measured using Ross filter pairs and a single-photon counting CCD, with approximately $10^{10}$ photons per shot at critical energy of 14 keV, with beam divergence of about 15 mrad. Finally, we demonstrated the viability of the X-ray source for applications through phase-contrast imaging of polymer samples and a biological specimen, at large contrast-to-noise ratios.
