Similarities, Differences, and Synergies Between Modern Laboratory-based XAS and Synchrotron Beamline Science

by Prof. Gerald Seidler (University of Washington)

109 (25b)



DESY, Notkestraße 85, 22607 Hamburg

Six years ago laboratory-based XAFS using conventional x-ray tubes for materials characterization was a dead field. A few legacy instruments based on 1970’s technology were still operating, but there had been no interest in its further development due to the growth of synchrotron-based XAFS access in the 1980’s. By the end of 2018, there were about 15 modern laboratory XAFS and XES systems worldwide for tender and hard x-rays. In a few years, the number of benchtop hard x-ray lab XAFS and XES systems will likely approach the number of hard x-ray XAFS synchrotron beamlines, about 200. Yet, we argue here, the two access modes will have relatively disjoint, complementary applications, and there is a high probability that the growth of lab XAFS will both increase the synchrotron user base and also improve the scientific productivity of synchrotron beamtime. In this talk, I’ll describe my group’s work in the ongoing renaissance of lab-based XAFS and XES using only conventional x-ray tubes. After summarizing the technology, I’ll address an operational mode that illustrates one of the ways that lab XAFS can augment synchrotron XAS. Specifically, there are now many demonstrated lab XAFS applications that share a common characteristic: progress requires iterated rapid, often daily, feedback in exactly the common meaning of the term “routine analytical chemistry”. Projects like these that demand high access over long periods of time do not fit the synchrotron facility mission or access model, even when the scientific merit is high. Examples will include education, phosphorus XES of quantum dots, in situ XANES studies of Li-ion pouch cells batteries, nanophase identification by XANES fingerprinting, analysis of hexavalent Cr faction in plastics for regulatory purposes, and oxidation state analysis of uranium.