Bonn 2010 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 85: Beschleunigerphysik VIII
T 85.3: Vortrag
Mittwoch, 17. März 2010, 14:35–14:50, HG ÜR 8
Density Measurement inside a Sapphire Capillary for Laser Wakefield Acceleration — •Tobias Weineisen1,2, Shao-wei Chou1,2, Matthias Fuchs1,2, Stefan Karsch1,2, and Florian Grüner1,2 — 1Max Planck Institut für Quantenoptik, München, Deutschland — 2Fakultät für Physik der LMU, München, Deutschland
Laser wakefield accelerators have shown 1 GeV electron beams from centimeter-length gas capillaries. However, these beams typically have energy spreads on the order of a few percent. In order to improve this, a plasma density gradient can be introduced to control the self-injection process of the electrons into the accelerating wakefield. First experiments have already shown stable electron bunches with longitudinal and transverse momentum spreads more than 10 times lower than previously achieved. The self-injection and acceleration can be combined by embedding a high-density gas jet into a capillary. A new method utilizing density dependence of Raman scattering has been used to characterize the gradient inside the capillary with a 12 mu resolution. This allowed us to measure a density drop of a factor of ten within a few hundred micrometers inside the capillary.