Explosive detection using pixellated X-ray diffraction (PixD)

O’Flynn, Daniel; Reid, C.; Christodoulou, Christiana; Wilson, Matthew D.; Veale, Matthew C.; Seller, P.; Hills, D. L.; Desai, Hemant; Wong, B; Speller, Robert

doi:10.1088/1748-0221/8/03/p03007

Cited by 40 publications

(36 citation statements)

References 12 publications

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“…However, while EDXRD is favored for rapid analysis, the increase in flux afforded by the broadband spectrum is limited by the need for high aspect ratio collimators i.e. collimators with a low angular acceptance, which limits the total amount of diffracted flux incident upon the detector [7]. This consideration is compounded by the relatively low values of coherent scatter cross section e.g.…”

Section: Introductionmentioning

confidence: 99%

Energy-dispersive X-ray diffraction using an annular beam

Dicken¹,

Evans²,

Rogers³

et al. 2015

Opt. Express

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Abstract:We demonstrate material phase identification by measuring polychromatic diffraction spots from samples at least 20 mm in diameter and up to 10 mm thick with an energy resolving point detector. Within our method an annular X-ray beam in the form of a conical shell is incident with its symmetry axis normal to an extended polycrystalline sample. The detector is configured to receive diffracted flux transmitted through the sample and is positioned on the symmetry axis of the annular beam. We present the experiment data from a range of different materials and demonstrate the acquisition of useful data with sub-second collection times of 0.5 s; equating to 0.15 mAs. Our technique should be highly relevant in fields that demand rapid analytical methods such as medicine, security screening and non-destructive testing. 12. D. Prokopiou, K. Rogers, P. Evans, S. Godber, and A. Dicken, "Discrimination of liquids by a focal construct Xray diffraction geometry," Appl. Radiat. Isot. 77, 160-165 (2013). 13. P. Evans, K. Rogers, A. Dicken, S. Godber, and D. Prokopiou, "X-ray diffraction tomography employing an annular beam," Opt. Express 22(10), 11930-11944 (2014). 14. R. D. Luggar, J. A. Horrocks, R. D. Speller, and R. J. Lacey, "Determination of the geometric blurring of an energy dispersive X-ray diffraction (EDXRD) system and its use in the simulation of experimentally derived diffraction profiles," Nucl. Instrum. Methods Phys. Res., Sect. A 383(2-3), 610-618 (1996). 15. B. Ghammraoui, V. Rebuffel, J. Tabary, C. Paulus, L. Verger, and P. Duvauchelle, "Effect of grain size on stability of X-ray diffraction patterns used for threat detection," Nucl. Instrum. Methods Phys. Res., Sect. A 683, 1-7 (2012).

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Section: Introductionmentioning

confidence: 99%

Energy-dispersive X-ray diffraction using an annular beam

Dicken¹,

Evans²,

Rogers³

et al. 2015

Opt. Express

View full text Add to dashboard Cite

show abstract

“…The spatial resolution afforded by the detector pixels enables angular scatter information to be preserved without the need for collimation of the scattered beam -this is true provided the sample thickness remains of the order of several millimetres [16] -and as such the counting statistics of the system are greatly improved with respect to previous EDXRD systems based on a single-element detector. Additionally, further information on the grain size present in the sample is preserved with the diffraction image, as can be seen by comparing the Debye-Scherrer rings in fine grain caffeine and distinct spots in large grain hexamine [7,8]. The peak widths for this diffraction technique are wider than those in diffractometer scans.…”

Section: Resultsmentioning

confidence: 99%

Energy-windowed, pixellated X-ray diffraction using the Pixirad CdTe detector

et al. 2017

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X-ray diffraction (XRD) is a powerful tool for material identification. In order to interpret XRD data, knowledge is required of the scattering angles and energies of X-rays which interact with the sample. By using a pixellated, energy-resolving detector, this knowledge can be gained when using a spectrum of unfiltered X-rays, and without the need to collimate the scattered radiation. Here we present results of XRD measurements taken with the Pixirad detector and a laboratorybased X-ray source. The cadmium telluride sensor allows energy windows to be selected, and the 62 μm pixel pitch enables accurate spatial information to be preserved for XRD measurements, in addition to the ability to take high resolution radiographic images. Diffraction data are presented for a variety of samples to demonstrate the capability of the technique for materials discrimination in laboratory, security and pharmaceutical environments. Distinct diffraction patterns were obtained, from which details on the molecular structures of the items under study were determined.

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“…In addition, the method is open to further exploitation, for example, using total scattering to obtain characteristic signals from amorphous/semi-crystalline materials (e.g. for medical and security applications [33,34]) and ultimately pair-distribution analysis opening up the potential to image small nanocrystalline and amorphous materials (invisible to standard XRD techniques) allowing identification without a priori knowledge.…”

Section: Discussionmentioning

confidence: 99%

Dark-field hyperspectral X-ray imaging

et al. 2014

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In recent times, there has been a drive to develop nondestructive X-ray imaging techniques that provide chemical or physical insight. To date, these methods have generally been limited; either requiring raster scanning of pencil beams, using narrow bandwidth radiation and/or limited to small samples. We have developed a novel full-field radiographic imaging technique that enables the entire physiochemical state of an object to be imaged in a single snapshot. The method is sensitive to emitted and scattered radiation, using a spectral imaging detector and polychromatic hard X-radiation, making it particularly useful for studying large dense samples for materials science and engineering applications. The method and its extension to three-dimensional imaging is validated with a series of test objects and demonstrated to directly image the crystallographic preferred orientation and formed precipitates across an aluminium alloy friction stir weld section.

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Explosive detection using pixellated X-ray diffraction (PixD)

Cited by 40 publications

References 12 publications

Energy-dispersive X-ray diffraction using an annular beam

Energy-dispersive X-ray diffraction using an annular beam

Energy-windowed, pixellated X-ray diffraction using the Pixirad CdTe detector

Dark-field hyperspectral X-ray imaging

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