XAFS measurement system using undulator synchronized on-the-fly monochromator scan at SPring-8 BL36XU

In X-ray absorption fine structure (XAFS) measurements at undulator beamlines, it has been difficult to simultaneously achieve both spectral time resolution and high X-ray flux that fully utilizes the optical performance of the beamline. To overcome this challenge, we developed a synchronization architecture for undulator beamlines, in which the undulator gap serves as the master axis while a compact channel-cut monochromator follows a pre-calculated nonlinear trajectory. In contrast to conventional feedback approaches, in which the monochromator serves as the master, the undulator gap is used as the master axis, enabling fast and flexible nonlinear synchronization with the compact channel-cut monochromator. Transmission and fluorescence quick-XAFS (QXAFS) measurements were successfully performed at the Ni K edge in the extended X-ray absorption fine structure (EXAFS) region within 6.4 s. The incident photon flux was six times higher than that of conventional QXAFS using a tapered and fixed undulator gap at the same acquisition time, demonstrating that the proposed synchronization architecture enables high-flux EXAFS measurements that were previously difficult to achieve with undulator-based QXAFS.