Hard X-rays QEXAFS instrumentation with scan range 20 to 4000 eV

The Quick Extended Absorption Fine Structure (QEXAFS) spectroscopy was developed at the National Synchrotron Light Source (NSLS) to learn on seconds and sub-seconds time scale of the structural changes in the material. The initial system was developed at beamline X18B [1], however, two drawbacks with this original system were (1) problems with scan frequencies <0.1 Hz due to insufficient power of the DC motor and (2) rough operation at large angles due to gravity pulling on the monochromator arm, which is parallel to the beam, giving rise to different durations of low to high and high to low energy scans. The beamline was not focused so there was not enough flux to get good quality data. To overcome these problems we developed a new QEXAFS system at focused beamline X18A and changed the mechanical arrangement of data collection. The whole driving mechanism is still outside the vacuum environment and the mode of operation can be changed to conventional EXAFS in few minutes without venting the monochromator chamber.