Reproducibility of electron beams from laser wakefield acceleration in capillary tubes

F.G. Desforges (1) , M. Hansson (2) , J. Ju (3) , L. Senje (4) , T.L. Audet (1) , S. Dobosz-Dufrénoy (5, 6) , A. Persson (4) , O. Lundh (7) , C.-G. Wahlström (4, 7) , B. Cros (1)

1 LPGP - Laboratoire de physique des gaz et des plasmas
2 Department of Chemistry
3 CAS - Chinese Academy of Sciences [Beijing]
4 Lund University [Lund]
5 PHI - Physique à Haute Intensité
6 LIDyl - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
7 Department of Physics

The stability of accelerated electron beams produced by self-injection of plasma electrons into the wakefield driven by a laser pulse guided inside capillary tubes is analyzed statistically in relation to laser and plasma parameters, and compared to results obtained in a gas jet. The analysis shows that reproducible electron beams are achieved with a charge of 66 pC ±11%, a FWHM beam divergence of 9 mrad ±14%, a maximum energy of 120 MeV ±10% and pointing fluctuations of 2.3 mrad using 10 mm long, 178µm diameter capillary tubes at an electron density of (10.0±1.5)×1018 cm-3. Active stabilization of the laser pointing was used and laser parameters were recorded on each shot. Although the shot-to-shot laser energy fluctuations can account for a fraction of the electrons fluctuations, gas density fluctuations are suspected to be a more important source of instability.

Domains: Physics [physics]; Physics [physics]

F.G. Desforges, M. Hansson, J. Ju, L. Senje, T.L. Audet, et al.. Reproducibility of electron beams from laser wakefield acceleration in capillary tubes. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2014, 740, pp.54--59. ⟨hal-01298070⟩