Full-field X-ray fluorescence imaging with a straight polycapillary X-ray collimator

Abstract

Due to the availability of X-ray imaging detectors, full-field X-ray fluorescence (FF-XRF) imaging technique has become achievable, which provides an alternative to scanning Xray fluorescence imaging with a micro-focus X-ray beamline. In this paper, we present a setup based on straight capillary optics and an energy-dispersive hybrid pixel detector, which can perform simultaneous mapping of several chemical elements. The photon transmission efficiency and spatial resolution are compared between two X-ray collimation setups: one using pinhole optics and one using straight polycapillary optics. There is a tradeoff between the spatial resolution and transmission efficiency when considering X-ray optics. When optimizing the spatial resolution, using straight capillary optics achieved a higher intensity gain when comparing with the pinhole setup. Characterization of the polycapillary imaging setup is performed through analyzing various samples in order to investigate the spatial-frequency response and the energy sensitivity. This developed setup is capable of FF-XRF imaging in characteristic energies below 20 keV, while for higher energies the spatial resolution is affected by photon transmission through the collimator. This work shows the potential of the FF-XRF instrument in the monitoring of toxic metal distributions in environmental mapping measurements.

Atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…The spatial resolution (effective pixel diameter) was 135 and 350 mm using pinholes of 100 and 300 mm, respectively. An impressive factorof-4 reduction of background signal and a 10% increase in analytical signal was achieved by An et al 19 by using a polycapillary optic instead of a pinhole. The detector consisted of an electronic component capable of reading individual pixels and bonded to a 256 Â 256 array silicon chip.…”

Capillary optics for full‐field x‐ray detectors with a magnification factor of 40 and 2.4 μm spatial resolution

“…8,9 To increase the intensity on the sample, a polycapillary lens can be added between the x-ray generator and the sample. The detection optic can be a pinhole, 10 micro-channel plate, 11,12 straight polycapillary collimator 13 or a PolyCCC, to project the secondary fluorescence of the sample on the x-ray camera. The x-ray camera itself can be energy dispersive, [14][15][16][17] or not, like a standard x-ray CCD 8 with or without scintillator.…”

The study of X-ray full-field imaging method for low atomic number elements based on Compton scattering

“…With the development of analytical technology, people are no longer satisfied with the traditional qualitative and quantitative analysis, and put forward new needs in the study of the spatial distribution of each chemical component of the material surface. X-ray imaging technology (XRFI) is one of the important means, in which the common X-ray imaging technology is mainly divided into scanning imaging and full-field imaging according to the imaging mode [1][2][3][4][5].…”