Multi-keV picosecond x-ray source development from ultra-intense kHz laser-cluster interaction

摘要

Multi-keV X-ray source from intense laser-cluster interaction was experimentally studied. A special effort was first made in order to characterize the cluster target. K-shell emission of Argon clusters (around 3 keV) was then studied when irradiated by kHz, 30 fs, 10~(17) W.cm~(-2) laser pulses. High-resolution spectra are presented, in this spectral range, as a function of laser duration and average cluster size. Signature of very highly charged ions (Ar~(16+)) was observed with relatively low intensity laser pulses (few 10~(15) W.cm~(-2)). This feature is not yet clearly understood nor reproduced by simulations. Optimal laser pulse duration was observed for X-ray production, depending on the cluster size. For the first time to our knowledge, the duration of K-shell X-ray bursts was measured with a home-made streak camera to be on the picosecond scale.