RESUMO
A four-channel ionization chamber has been designed, constructed and tested. This ionization chamber allows X-ray absorption spectra to be collected in transmission from up to four samples simultaneously. This results in spectra that are free of systematic uncertainty in relative energy alignment introduced by scan-to-scan stability of the monochromator or of numerical uncertainty associated with a post-processing alignment algorithm, allowing, in a single shot, an absolute measure of edge shift between four samples of different valence. As four samples can be measured in parallel, the time expended over the course of an experiment to cycle the measurement environment between its rest state and the measurement condition is substantially reduced. The ionization chamber is simple in design and could be implemented at virtually any XAFS beamline with a horizontal fan of radiation such as that provided by a bend magnet or wiggler.
