Deducing the Electron-Beam Diameter in a Laser-Plasma Accelerator Using X-Ray Betatron Radiation

Abstract

We investigate the properties of a laser-plasma electron accelerator as a bright source of keV x-ray radiation. During the interaction, the electrons undergo betatron oscillations and from the carefully measured x-ray spectrum the oscillation amplitude of the electrons can be deduced which decreases with increasing electron energies. From the oscillation amplitude and the independently measured x-ray source size of $(1.8\pm 0.3)\mu \mathrm{m}$ we are able to estimate the electron bunch diameter to be $(1.6\pm 0.3)\mu \mathrm{m}$. DOI: http://dx.doi.org/10.1103/PhysRevLett.108.075001 © 2012 American Physical Society