RESUMO
A new setup and commissioning of transient X-ray absorption spectroscopy are described, based on the high-repetition-rate laser pump/X-ray probe method, at the 1W2B wiggler beamline at the Beijing Synchrotron Radiation Facility. A high-repetition-rate and high-power laser is incorporated into the setup with in-house-built avalanche photodiodes as detectors. A simple acquisition scheme was applied to obtain laser-on and laser-off signals simultaneously. The capability of picosecond transient X-ray absorption spectroscopy measurement was demonstrated for a photo-induced spin-crossover iron complex in 6â mM solution with 155â kHz repetition rate.
RESUMO
The implementation of a laser pump/X-ray probe scheme for performing picosecond-resolution X-ray diffraction at the 1W2B wiggler beamline at Beijing Synchrotron Radiation Facility is reported. With the hybrid fill pattern in top-up mode, a pixel array X-ray detector was optimized to gate out the signal from the singlet bunch with interval 85â ns from the bunch train. The singlet pulse intensity is â¼2.5 × 10(6)â photonsâ pulse(-1) at 10â keV. The laser pulse is synchronized to this singlet bunch at a 1â kHz repetition rate. A polycapillary X-ray lens was used for secondary focusing to obtain a 72â µm (FWHM) X-ray spot. Transient photo-induced strain in BiFeO3 film was observed at a â¼150â ps time resolution for demonstration.