Development of confocal X-ray fluorescence (XRF) microscopy at the Cornell high energy synchrotron source

Abstract

A confocal x-ray fluorescence microscope was built at the Cornell High Energy Synchrotron Source (CHESS) to determine the composition of buried paint layers that range from 10-80 µm thick in paintings. The microscope consists of a borosilicate monocapillary optic to focus the incident beam and a borosilicate polycapillary lens to collect the fluorescent x-rays. The overlap of the two focal regions is several tens of microns in extent, and defines the active, or confocal, volume of the microscope. The capabilities of the technique were tested using acrylic paint films with distinct layers brushed onto glass slides and a twentieth century oil painting on canvas. The position and thickness of individual layers were extracted from their fluorescence profiles by fitting to a simple, semi-empirical model.

Application of Confocal 3D Micro-XRF for Solid/Liquid Interface Analysis

“…A similar result was reported concerning synchrotron radiation induced 3D-XRF. 13 Total reflection of x-rays occurs in a polycapillary x-ray lens. Total reflection of x-rays depends on the energy of x-rays.…”

“…[8][9][10] We confirmed highly effective excitation for light elements by applying a Cr target. 11 The 3D-XRF method has been applied for the analysis of various samples, such as paint chips, 12 layered materials, 13 particles in a BN matrix, 7 and Amaranth seed. 11 However, as far as we know, 3D-XRF has not been applied for the analysis of solid/liquid interfaces.…”

Germanium collimating micro-channel arrays for high resolution, high energy confocal X-ray fluorescence microscopy

“…Since its first practical demonstration just over ten years ago [1][2][3][4][5], confocal x-ray fluorescence microscopy (CXRF) has become increasingly well known and commonly applied as a means of directly measuring 3D elemental composition in heterogeneous samples. CXRF is performed by scanning a 3D probe volume, defined by the overlapping foci of an excitation optic and a collection optic, through a sample of interest.…”

X-ray Energy Dependence of the Properties of the Focused Beams Produced by Polycapillary X-ray Lens

“…Recently, a confocal 3D m-XRF analysis combined with two polycapillary x-ray lenses [16][17][18] and with two capillaries 19 has been reported. In Ref.…”

“…In Ref. 19,Woll et al reported that the confocal volume of a confocal 3D m-XRF had an energy dependence that originated from a polycapillary x-ray lens. Therefore, it is important to understand clearly the characteristics of the polycapillary lens.…”