Detectors for energy-dispersive EXAFS (EDE) experiments

摘要

EXAFS, X-ray absorption spectroscopy fine structure, has been an important tool within synchrotron radiation science for some years. It has been used extensively in step scanning mode to provide information on the local environment within both static and slowly changing samples.Energy-dispersive EXAFS (EDE) allows similar information to be collected in a significantly shorter time frame, enabling the study of truly dynamically changing samples. The technique uses a bent crystal monochromator to focus an energy-dispersed X-ray beam onto a sample which then impinges upon an array detector positioned behind the sample. This allows the absorption over a range of energies to be collected in a very short period. Until recently only few systems have existed for this technique, typically employing commercially available detectors originally constructed for other applications. These presented limitations in speed, energy resolution, linearity and dynamic range and could only follow changes in the millisecond range.Using UK ESPRC grant funds, a new detector has been developed (XSTRIP) which shows great improvements over the above limitations and has demonstrated the potential to open new areas of science to researchers.This paper will present the technique, some of the historical limitations, the performance increase afforded by the XSTRIP system and an overview of the future direction of detectors for this most exciting and important technique. (c) 2005 Elsevier B.V. All rights reserved.