On-the-fly Scan: Improving the Performance of Absorption Spectrum Measurement

Abstract

The efficiency of conventional point-to-point scan is limited by overheads from mechanical system and data acquisition system. With network-friendly development interface provided by commercial software and hardware, the DAQ system, the position encoding system, the undulator, and the monochromator system can be easily controlled by synchronizing various instruments for on-the-fly scanning operation. In this work, an on-the-fly scanning method is developed for absorption spectrum measurement under the Labview's programing environment. We have tested its performance on Dragon type beamlines at NSRRC. For a given energy resolution and a S/N level our preliminary results show that the time required to obtain a spectrum of Near Edge X-ray Absorption Fine Structure (NEXAFS) and X-ray Absorption Spectroscopy (XAS) using the on-the-fly scanning system is about 10 times and 20 times shorter than those using the point-to-point scanning with bending magnet and undulator sources, respectively. The higher efficiency gained from the on-the-fly scanning system results from minimizing system communication time and mechanical system overheads. The new improved technique should significantly contribute to the study and measurement of photon dose sensitive samples.