Time-resolved X-ray absorption spectroscopy and its applied researches

The time-resolved dispersive XAFS (DXAFS) system for irreversible processes has been developed at the NW2A beamline of PF-AR. Combining the DXAFS system that can detect one pulse x-ray of duration ∼100 ps emitted every 1.26 μs from PF-AR with a high power pulsed laser enabled elucidation of laser-driven irreversible processes with nanosecond to subnanosecond time resolution. We applied the system to the laser compression and laser ablation process of metals as an irreversible process, and succeeded in obtaining the time evolution of the processes under extreme conditions from the change of XAFS spectra obtained. In the case of laser compression of copper, it was found that copper was compressed by about 2% in volume after 4 ns from laser irradiation and the pressure was released over 200 ns. A part of this report is derived in part form an article published in High Pressure Research on 2 Aug 2016, available online at : http://www.tandfonline.com/10.1080/08957959.2016.1211647. (author)