München 2004 – scientific programme
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Q: Quantenoptik und Photonik
Q 10: Ultrakurze Lichtimpulse: Röntgenpulse und Kernphysik
Q 10.2: Talk
Monday, March 22, 2004, 16:45–17:00, HS 223
Enhancement of high-repetition-rate femtosecond laser generated x-ray fluxes — •M. Silies, J. Kutzner, T. Witting, M. Hagedorn, G. Tsilimis, and H. Zacharias — Physikalisches Institut, Westfälische Wilhelms-Universtität, Münster, Wilhelm-Klemm-Str. 10, D-48149 Münster
The generation of hard x-rays has been investigated with a laser-based, compact, hard x-ray source, particularly suited for high-repetition rate laser systems (1-10 kHz). Sub-millijoule, 25 fs Ti:Sapphire laser pulses are applied to generate hard x-ray radiation with a commercially available ferric audio tape target. Spectroscopic investigations show strong Kα-emission in addition to a weak Bremsstrahlung continuum. Particular interest has been spend to the x-ray yield enhancement while applying pre-pulse as well as multiple-shot exposure techniques. Under single exposure, single pulse conditions the x-ray yield is low, but increases with increasing pulse energy and reaches a energy conversion efficiencies of ηKα=2·10−7. Depending on the applied pulse energy and intensity, the x-ray yield is enhanced by more than three orders of magnitude with the pre-pulse as well as with the multiple-shot exposure technique. Photon fluxes exceeding 2· 109 photons/s were generated with the tape target providing conversion efficiencies approaching ηKα= 10−5.