Energy dispersive detector for white beam synchrotron x-ray fluorescence imaging

Abstract

Abstract.A novel, "single-shot" fluorescence imaging technique has been demonstrated on the B16 beamline at the Diamond Light Source synchrotron using the HEXITEC energy dispersive imaging detector. A custom made furnace with 200μm thick metal alloy samples was positioned in a white X-ray beam with a hole made in the furnace walls to allow the transmitted beam to be imaged with a conventional X-ray imaging camera consisting of a 500 μm thick single crystal LYSO scintillator, mirror and lens coupled to an AVT Manta G125B CCD sensor. The samples were positioned 45° to the incident beam to enable simultaneous transmission and fluorescence imaging. The HEXITEC detector was positioned at 90° to the sample with a 50μm pinhole 13cm from the sample and the detector positioned 2.3m from pinhole. The geometric magnification provided a field of view of 1.1x1.1mm 2 with one of the 80x80 pixels imaging an area equivalent to 13μm 2 . Al-Cu alloys doped with Zr, Ag and Mo were imaged in transmission and fluorescence mode. The fluorescence images showed that the dopant metals could be simultaneously imaged with sufficient counts on all 80x80 pixels within 60s, with the X-ray flux limiting the fluorescence imaging rate. This technique demonstrated that it is possible to simultaneously image and identify multiple elements on a spatial resolution scale ~10μm or higher without the time consuming need to scan monochromatic energies or raster scan a focused beam of X-rays. Moving to high flux beamlines and using an array of detectors could improve the imaging speed of the technique with element specific imaging estimated to be on a 1s timescale.

Characterization of a Pixelated Cadmium Telluride Detector System Using a Polychromatic X-Ray Source and Gold Nanoparticle-Loaded Phantoms for Benchtop X-Ray Fluorescence Imaging

“…In essence, the current study represents the first-time testing, to the best of our knowledge, of HEXITEC in an ordinary polychromatic x-ray beam line to detect XRF photons emitted by GNPs. The performance of HEXITEC for XRF applications was demonstrated previously under the monochromatic synchrotron x-ray environment [15,19]. On the other hand, little is known at this time regarding its performance under the benchtop setting where the use of polychromatic diagnostic energy range x-ray sources (e.g., tube voltages > 100 kVp) results in more pronounced scatter background, introducing additional complexity in detection/extraction of XRF signals.…”

“…Meanwhile, we noted a commercial pixelated detector system that appeared to allow for parallel XRF signal acquisition while meeting the technical requirements, especially in terms of the detector energy resolution, for the latest version of our benchtop cone-beam XFCT system [11]. This detector system, known as HEXITEC (High Energy X-ray Imaging Technology) [12][13][14], is based on a fully-spectroscopic pixelated cadmium telluride (CdTe) detector, and has been successfully used for XRF imaging with monochromatic synchrotron x-rays [15]. A recent study also reported the use of HEXITEC to create a multi-detector array for single-photon imaging applications [16].…”