X-ray absorption tomography employing a conical shell beam

Evans, Paul; Godber, Simon X.; Elarnaut, F.; Downes, David; Dicken, Anthony; Rogers, Keith

doi:10.1364/oe.24.029048

Cited by 8 publications

(12 citation statements)

References 25 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fast and accurate identification of commercial and homemade explosives (HMEs) is a critical consideration in this problem space. Our paper is a natural extension of this prior body of work and in particular our work on FCG transmission tomography [21] and diffraction tomography [22]. It reports the first demonstration of combined XRD and absorption FCG tomography using a single conical shell beam and detection surface.…”

Section: Theory Backgroundmentioning

confidence: 76%

“…Each snapshot comprises a primary beam footprint together with caustics [22] in the diffracted flux within the central detection area. The measurements of absorption contrast at fixed polar coordinate positions R on each different transmission absorption ring, collected by a fixed detector pixel, may be composited to form oblique projections [21]. The maximum total number of different oblique projections is equal to the total number of detector pixels or sampling positions around the primary beam footprint.…”

Section: Combined Imaging Techniquementioning

confidence: 99%

“…In this paper, we report for the first time the combined application of tomosynthesis to absorption image contrast and XRD signals collected simultaneously via a single scanning hollow beam probe and planar detector. We build directly upon our prior work, which has developed conical shell absorption tomography [21] and independently, conical shell XRD tomography [22]. In our approach, the sample acts as a 'diffractive lens' to focus coherent scatter onto a detector placed within the central dark area and surrounded by the primary beam.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Combined X-ray diffraction and absorption tomography using a conical shell beam

Shevchuk¹,

Evans²,

Dicken³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

We combine diffraction and absorption tomography by raster scanning samples through a hollow cone of pseudo monochromatic X-rays with a mean energy of 58.4 keV. A single image intensifier takes 90x90 (x,y) snapshots during the scan. We demonstrate a proofof-principle of our technique using a heterogeneous three-dimensional (x,y,z) phantom (90x90x170 mm 3 ) comprised of different material phases, i.e., copper and sodium chlorate. Each snapshot enables the simultaneous measurement of absorption contrast and diffracted flux. The axial resolution was ~1 mm along the (x,y) orthogonal scan directions and ~7 mm along the z-axis. The tomosynthesis of diffracted flux measurements enable the calculation of d-spacing values with ~0.1 Å full width at half maximum (FWHM) at ~2 Å. Thus the identified materials may be color-coded in the absorption optical sections. Characterization of specific material phases is of particular interest in security screening for the identification of narcotics and a wide range of homemade explosives concealed within complex "everyday objects." Other potential application areas include process control and biological imaging. IntroductionRadiographic imaging and the structural analysis of materials using X-rays developed disparately soon after the discovery of X-rays in 1895 [1]. The former has evolved from simple planar imaging into sophisticated tomographic methods [2,3], while the latter formed the basis of X-ray crystallography. Each approach demands quite different spatiotemporal collection and sensing requirements [4,5]. In general, incident X-rays composing a spatial image propagate along a linear path from the source to the detector and do not interact with the materials under inspection. However, the spectroscopic analysis of the transmitted X-rays may provide some useful materials discrimination information [6]. Ultimately, such approaches are limited fundamentally and cannot provide structural or 'molecular resolution' analysis. In contrast, determination of the atomic and molecular structure of crystalline/polycrystalline materials requires analysis of coherently scattered or diffracted Xrays from a sample. The relatively low energy of the interrogating radiation used in laboratory X-ray diffraction (XRD) limits penetration into the sample to near the incident surface. Significantly higher X-ray energies are required (i.e. an order of magnitude increase in photon energy over the legacy 8 keV Cu Kα [7]) for transmission mode diffraction for highly absorbing and or extended thickness samples [7][8][9]. Conventional fan beam tomography has provided diffracted flux measurements [5,[9][10][11] to demonstrate spatially-resolved material specific profiles. Novel compressive tomography promises further reductions in scan times and exposure [12][13][14]. The common problem confronting all volumetric XRD scanning/imaging methods is the production and measurement of sufficient diffracted flux or signal photons to provide the desired scan speed at application dependent energies. These consideration...

show abstract

Section: Theory Backgroundmentioning

confidence: 76%

Section: Combined Imaging Techniquementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Combined X-ray diffraction and absorption tomography using a conical shell beam

Shevchuk¹,

Evans²,

Dicken³

et al. 2019

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…A conical shell beam of radiation provides an extended specimen path that increases the number of crystallites in the correct orientation to produce relatively high intensity focal spots [16] and caustics in the diffracted flux [17]. This beam topology has been implemented successfully in energy [18] and angular dispersive modes [19][20][21], used to identify liquid samples [19], and shown to deal favorably with non-ideal samples in which scattering distributions are adversely affected by crystallographic textures e.g. preferred orientation and large grain size [20].…”

Section: Theory Backgroundmentioning

confidence: 99%

“…preferred orientation and large grain size [20]. In addition, annular projections collected over a two-axis raster scan can optically encode the shape and location of object features along the beam to provide the basis for absorption contrast tomography [21], and angular-dispersive tomography [22]. An angular-dispersive method employing spiral or linear post sample occluders [23] to provide depth encoding has also been implemented although this method does not collect spatial images.…”

Section: Theory Backgroundmentioning

confidence: 99%

Depth resolved snapshot energy-dispersive X-ray diffraction using a conical shell beam

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract:We demonstrate a novel imaging architecture to collect range encoded diffraction patterns from overlapping samples in a single conical shell projection. The patterns were measured in the dark area encompassed by the beam via a centrally positioned aperture optically coupled to a pixelated energy-resolving detector. We show that a single exposure measurement of 0.3 mAs enables d-spacing values to be calculated. The axial positions of the samples were not required and the resultant measurements were robust in the presence of crystallographic textures. Our results demonstrate rapid volumetric materials characterization and the potential for a direct imaging method, which is of great relevance to applications in medicine, non-destructive testing and security screening. 457-460 (1987). 30. C. V. Pabón, P. Frutos, J. L. Lastres, and G. Frutos, "Application of differential scanning calorimetry and X-ray powder diffraction to the solid-state study of metoclopramide," J. Pharm. Biomed. Anal. 15(1), 131-138 (1996).

show abstract

Conical shell X-ray beam tomosynthesis and micro-computed tomography for microarchitectural characterisation

Arnold,

Elarnaut,

Downes

et al. 2023

Sci Rep

View full text Add to dashboard Cite

Bone quality is commonly used to diagnose bone diseases such as osteoporosis, with many studies focusing on microarchitecture for fracture prediction. In this study a bovine distal femur was imaged using both micro-computed tomography (µCT) and tomosynthesis using focal construct geometry (FCG) for comparison of microarchitectural parameters. Six regions of interest (ROIs) were compared between the two imaging modalities, with both global and adaptive methods used to binarize the images. FCG images were downsampled to the same pixel size as the µCT images. Bone morphometrics were determined using BoneJ, for each imaging modality, binarization technique and ROI. Bone area/total area was found to have few significant differences between FCG and µCT (p < 0.05 for two of six ROIs). Fractal Dimension had only one significant difference (p < 0.05 for one of six ROIs) between µCT and downsampled FCG (where pixel size was equalized). Trabecular thickness and trabecular spacing were observed to follow trends as observed for the corresponding µCT images, although many absolute values were significantly different (p < 0.05 for between one and six ROIs depending on image types used). This study demonstrates the utility of tomosynthesis for measurement of microarchitectural morphometrics.

show abstract

X-ray absorption tomography employing a conical shell beam

Cited by 8 publications

References 25 publications

Combined X-ray diffraction and absorption tomography using a conical shell beam

Combined X-ray diffraction and absorption tomography using a conical shell beam

Depth resolved snapshot energy-dispersive X-ray diffraction using a conical shell beam

Conical shell X-ray beam tomosynthesis and micro-computed tomography for microarchitectural characterisation

Contact Info

Product

Resources

About