Polycapillary Optics Based Confocal Micro X-ray Fluorescence and X-ray Absorption Spectroscopy Setup at The European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A

A novel plug-and-play setup based on polycapillary X-ray optics enables three-dimensional (3D) confocal X-ray fluorescence (XRF) and X-ray absorption spectroscopy down to 8 × 8 × 11 μm³ (17 keV) at the European Synchrotron Radiation Facility Collaborative Research Group Dutch-Belgian Beamline, BM26A. A complete description and analytical characterization is presented, together with two recently performed experimental cases. In Deep Earth diamond São Luiz-Frankfurt am Main 16, an olivine-rich inclusion was mapped with full 3D XRF elemental imaging. The preliminary tests on Iron Gall ink contained in an historical document, a letter from the court of King Philip II of Spain, reveal both the delicate nature of Iron Gall ink and the lack of Fe-Ni chemical bonding.

Confocal depth-resolved fluorescence micro-X-ray absorption spectroscopy for the study of cultural heritage materials: a new mobile endstation at the Beijing Synchrotron Radiation Facility

A confocal fluorescence endstation for depth-resolved micro-X-ray absorption spectroscopy is described. A polycapillary half-lens defines the incident beam path and a second polycapillary half-lens at 90° defines the probe sample volume. An automatic alignment program based on an evolutionary algorithm is employed to make the alignment procedure efficient. This depth-resolved system was examined on a general X-ray absorption spectroscopy (XAS) beamline at the Beijing Synchrotron Radiation Facility. Sacrificial red glaze (AD 1368-1644) china was studied to show the capability of the instrument. As a mobile endstation to be applied on multiple beamlines, the confocal system can improve the function and flexibility of general XAS beamlines, and extend their capabilities to a wider user community.

Application toward Confocal Full-Field Microscopic X-ray Absorption Near Edge Structure Spectroscopy

Using X-ray absorption near edge structure (XANES) spectroscopy, information on the local chemical structure and oxidation state of an element of interest can be acquired. Conventionally, this information can be obtained in a spatially resolved manner by scanning a sample through a focused X-ray beam. Recently, full-field methods have been developed to obtain direct 2D chemical state information by imaging a large sample area. These methods are usually in transmission mode, thus restricting the use to thin and transmitting samples. Here, a fluorescence method is displayed using an energy-dispersive pnCCD detector, the SLcam, characterized by measurement times far superior to what is generally applicable. Additionally, this method operates in confocal mode, thus providing direct 3D spatially resolved chemical state information from a selected subvolume of a sample, without the need of rotating a sample. The method is applied to two samples: a gold-supported magnesia catalyst (Au/MgO) and a natural diamond containing Fe-rich inclusions. Both samples provide XANES spectra that can be overlapped with reference XANES spectra, allowing this method to be used for fingerprinting and linear combination analysis of known XANES reference compounds.