Pico-second time-resolved X-ray absorption near edge spectrometer

Dr. F. Dorchies (Universite Bordeaux, CNRS-CELIA, France) and his colleagues have recently developed a laser-base X-ray absorption spectrometer covering 0.5-4.0 keV with a time resolution of around 3.3 pico second. The spectrometer uses bremsstrahlung caused by the extremely high impact of laser pulses on the metallic target. To perform time-resolved X-ray spectroscopic studies, there have been quite a few challenges. For most research, it is crucial to avoid damaging/destroying samples, and the measuring time should not be very long. In addition, scientists don't like to compromise the signal-to-background ratio of spectral data taken at each time point, even though the quality is not the same as that of ordinary X-ray absorption spectra. The authors seem to believe that they are getting some breakthroughs. Their setup is a combination of a table-top laser (Ti: Sapphire, 800nm, 150mJ, 10Hz) and a Johan spectrometer equipped with a CCD camera. A set of polycapillary optics were employed as a beamline transport between the X-ray source and the sample (1 m distance) to maintain a clean, independent and flexible environment for the sample. The X-ray intensity near the Al K edge and Cu L edges is 1.3 × 10⁶ photons/eV/pulse. For more information, see the paper, "Experimental station for laser-based picosecond time-resolved x-ray absorption near-edge spectroscopy", F. Dorchies et al., Rev. Sci. Instrum. 86, 073106 (2015).