Study of electron acceleration and x-ray radiation as a function of plasma density in capillary-guided laser wakefield accelerators

Laser wakefield electron acceleration in the blow-out regime and the associated betatron X-rayradiation were investigated experimentally as a function of the plasma density in a configuration where the laser is guided. Dielectric capillary tubes were employed to assist the laser keeping self-focused over a long distance by collecting the laser energy around its central focal spot. With a 40 fs, 16 TW pulsed laser, electron bunches with tens of pC charge were measured to be accelerated to an energy up to 300 MeV, accompanied by X-ray emission with a peak brightness of the order of 10 21 ph/s/mm 2 / mrad 2 /0.1%BW. Electron trapping and acceleration were studied using the emitted X-ray beamdistribution to map the acceleration process; the number of betatron oscillations performed by theelectrons was inferred from the correlation between measured X-ray fluence and beam charge. A studyof the stability of electron and X-ray generation suggests that the fluctuation of X-ray emission can be reduced by stabilizing the beam charge. The experimental results are in good agreement with 3D particle-in-cell (PIC) simulation. Fil: Ju, L.. Universite de Paris Xi; Francia; Fil: Svensson, K.. Lund University; Suecia Fil: Ferrari, Hugo Emilio. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (centro Atómico Bariloche); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Döpp, A.. Universite de Paris Xi; Francia; Fil: Cassou, K.. Universite de Paris Xi; Francia; Fil: Genoud, G.. Lund University; Suecia; Fil: Wojda, F.. Lund University; Suecia; Fil: Burza, M.. Lund University; Suecia; Fil: Persson, A.. Lund University; Suecia; Fil: Lundh, O.. Lund University; Suecia; Fil: Wahlström, C. G.. Lund University; Suecia; Fil: Cros, B.. Universite de Paris Xi; Francia