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Kuppili VSC, Ball M, Batey D, Dodds K, Cipiccia S, Wanelik K, Fu R, Rau C, Harrison RJ. Nanoscale imaging of Fe-rich inclusions in single-crystal zircon using X-ray ptycho-tomography. Sci Rep 2024; 14:5139. [PMID: 38429500 PMCID: PMC10907758 DOI: 10.1038/s41598-024-55846-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 02/28/2024] [Indexed: 03/03/2024] Open
Abstract
We apply X-ray ptycho-tomography to perform high-resolution, non-destructive, three-dimensional (3D) imaging of Fe-rich inclusions in paleomagnetically relevant materials (zircon single crystals from the Bishop Tuff ignimbrite). Correlative imaging using quantum diamond magnetic microscopy combined with X-ray fluorescence mapping was used to locate regions containing potential ferromagnetic remanence carriers. Ptycho-tomographic reconstructions with voxel sizes 85 nm and 21 nm were achievable across a field-of-view > 80 µm; voxel sizes as small as 5 nm were achievable over a limited field-of-view using local ptycho-tomography. Fe-rich inclusions 300 nm in size were clearly resolved. We estimate that particles as small as 100 nm-approaching single-domain threshold for magnetite-could be resolvable using this "dual-mode" methodology. Fe-rich inclusions (likely magnetite) are closely associated with apatite inclusions that have no visible connection to the exterior surface of the zircon (e.g., via intersecting cracks). There is no evidence of radiation damage, alteration, recrystallisation or deformation in the host zircon or apatite that could provide alternative pathways for Fe infiltration, indicating that magnetite and apatite grew separately as primary phases in the magma, that magnetite adhered to the surfaces of the apatite, and that the magnetite-coated apatite was then encapsulated as primary inclusions within the growing zircon. Rarer examples of Fe-rich inclusions entirely encapsulated by zircon are also observed. These observations support the presence of primary inclusions in relatively young and pristine zircon crystals. Combining magnetic and tomography results we deduce the presence of magnetic carriers that are in the optimal size range for carrying strong and stable paleomagnetic signals but that remain below the detection limits of even the highest-resolution X-ray tomography reconstructions. We recommend the use of focused ion beam nanotomography and/or correlative transmission electron microscopy to directly confirm the presence of primary magnetite in the sub 300 nm range as a necessary step in targeted paleomagnetic workflows.
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Affiliation(s)
- Venkata S C Kuppili
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK.
- Canadian Light Source, University of Saskatchewan, 44 Innovation Boulevard, Saskatoon, SK, S7N 2V3, Canada.
| | - Matthew Ball
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
| | - Darren Batey
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - Kathryn Dodds
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
| | - Silvia Cipiccia
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
- Department of Medical Physics and Biomedical Engineering, University College London, Gower St, London, WC1E 6BT, UK
| | - Kaz Wanelik
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - Roger Fu
- Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Christoph Rau
- Diamond Light Source, Harwell Campus, Didcot, OX11 0DE, UK
| | - Richard J Harrison
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
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2
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Doherty A, Fourmaux S, Astolfo A, Ziesche R, Wood J, Finlay O, Stolp W, Batey D, Manke I, Légaré F, Boone M, Symes D, Najmudin Z, Endrizzi M, Olivo A, Cipiccia S. Femtosecond multimodal imaging with a laser-driven X-ray source. Commun Phys 2023; 6:288. [PMID: 38665412 PMCID: PMC11041725 DOI: 10.1038/s42005-023-01412-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/04/2023] [Indexed: 04/28/2024]
Abstract
Laser-plasma accelerators are compact linear accelerators based on the interaction of high-power lasers with plasma to form accelerating structures up to 1000 times smaller than standard radiofrequency cavities, and they come with an embedded X-ray source, namely betatron source, with unique properties: small source size and femtosecond pulse duration. A still unexplored possibility to exploit the betatron source comes from combining it with imaging methods able to encode multiple information like transmission and phase into a single-shot acquisition approach. In this work, we combine edge illumination-beam tracking (EI-BT) with a betatron X-ray source and present the demonstration of multimodal imaging (transmission, refraction, and scattering) with a compact light source down to the femtosecond timescale. The advantage of EI-BT is that it allows multimodal X-ray imaging technique, granting access to transmission, refraction and scattering signals from standard low-coherence laboratory X-ray sources in a single shot.
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Affiliation(s)
- Adam Doherty
- Department of Medical Physics and Biomedical Engineering, University College London, 2 Malet Pl, London, WC1E 7JE UK
| | - Sylvain Fourmaux
- Institut National de la Recherche Scientifique—Énergie, Matériaux et Télécommunications, Université du Québec, 1650 Lionel Boulet, Varennes, J3X 1P7 QC Canada
| | - Alberto Astolfo
- Department of Medical Physics and Biomedical Engineering, University College London, 2 Malet Pl, London, WC1E 7JE UK
| | - Ralf Ziesche
- Helmholtz-Zentrum Berlin für Materialien und Energie Hahn Meitner Platz 1, 14109 Berlin, Germany
| | - Jonathan Wood
- The John Adam Institute for Accelerator Science, Imperial College London, Prince Consort Road, South Kensington, London, SW7 2BW UK
| | - Oliver Finlay
- Central Laser Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX UK
| | - Wiebe Stolp
- UGCT-RP, Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium
| | - Darren Batey
- Diamond Light Source, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX UK
| | - Ingo Manke
- Helmholtz-Zentrum Berlin für Materialien und Energie Hahn Meitner Platz 1, 14109 Berlin, Germany
| | - François Légaré
- Institut National de la Recherche Scientifique—Énergie, Matériaux et Télécommunications, Université du Québec, 1650 Lionel Boulet, Varennes, J3X 1P7 QC Canada
| | - Matthieu Boone
- UGCT-RP, Department of Physics and Astronomy, Ghent University, 9000 Ghent, Belgium
| | - Dan Symes
- Central Laser Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot, OX11 0QX UK
| | - Zulfikar Najmudin
- The John Adam Institute for Accelerator Science, Imperial College London, Prince Consort Road, South Kensington, London, SW7 2BW UK
| | - Marco Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, 2 Malet Pl, London, WC1E 7JE UK
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, 2 Malet Pl, London, WC1E 7JE UK
| | - Silvia Cipiccia
- Department of Medical Physics and Biomedical Engineering, University College London, 2 Malet Pl, London, WC1E 7JE UK
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Hu Z, Zhang Y, Li P, Batey D, Maiden A. Near-field multi-slice ptychography: quantitative phase imaging of optically thick samples with visible light and X-rays. Opt Express 2023; 31:15791-15809. [PMID: 37157672 DOI: 10.1364/oe.487002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Ptychography is a form of lens-free coherent diffractive imaging now used extensively in electron and synchrotron-based X-ray microscopy. In its near-field implementation, it offers a route to quantitative phase imaging at an accuracy and resolution competitive with holography, with the added advantages of extended field of view and blind deconvolution of the illumination beam profile from the sample image. In this paper we show how near-field ptychography can be combined with a multi-slice model, adding to this list of advantages the unique ability to recover high-resolution phase images of larger samples, whose thickness places them beyond the depth of field of alternative methods.
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Batey D, Rau C, Cipiccia S. High-speed X-ray ptychographic tomography. Sci Rep 2022; 12:7846. [PMID: 35551474 PMCID: PMC9098852 DOI: 10.1038/s41598-022-11292-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 04/05/2022] [Indexed: 11/09/2022] Open
Abstract
X-ray ptychography is a coherent scanning imaging technique widely used at synchrotron facilities for producing quantitative phase images beyond the resolution limit of conventional x-ray optics. The scanning nature of the technique introduces an inherent overhead to the collection at every scan position and limits the acquisition time of each 2D projection. The overhead associated with motion can be minimised with a continuous-scanning approach. Here we present an acquisition architecture based on continuous-scanning and up-triggering which allows to record ptychographic datasets at up to 9 kHz. We demonstrate the method by applying it to record 2D scans at up to 273 µm2/s and 3D scans of a (20 µm)3 volume in less than three hours. We discuss the current limitations and the outlook toward the development of sub-second 2D acquisition and minutes-long 3D ptychographic tomograms.
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Affiliation(s)
- Darren Batey
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot, OX11 0DE, UK.
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot, OX11 0DE, UK
| | - Silvia Cipiccia
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Ave, Didcot, OX11 0DE, UK.,Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
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5
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Weber S, Batey D, Cipiccia S, Stehle M, Abel KL, Gläser R, Sheppard TL. Hard X-Ray Nanotomography for 3D Analysis of Coking in Nickel-Based Catalysts. Angew Chem Int Ed Engl 2021; 60:21772-21777. [PMID: 34339595 PMCID: PMC8518723 DOI: 10.1002/anie.202106380] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/13/2021] [Indexed: 12/24/2022]
Abstract
Understanding catalyst deactivation by coking is crucial for knowledge-based catalyst and process design in reactions with carbonaceous species. Post-mortem analysis of catalyst coking is often performed by bulk characterization methods. Here, hard X-ray ptychographic computed tomography (PXCT) was used to study Ni/Al2 O3 catalysts for CO2 methanation and CH4 dry reforming after artificial coking treatment. PXCT generated quantitative 3D maps of local electron density at ca. 80 nm resolution, allowing to visualize and evaluate the severity of coking in entire catalyst particles of ca. 40 μm diameter. Coking was primarily revealed in the nanoporous solid, which was not detectable in resolved macropores. Coke formation was independently confirmed by operando Raman spectroscopy. PXCT is highlighted as an emerging characterization tool for nanoscale identification, co-localization, and potentially quantification of deactivation phenomena in 3D space within entire catalyst particles.
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Affiliation(s)
- Sebastian Weber
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT)Engesserstr. 2076131KarlsruheGermany
- Institute of Catalysis Research and TechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
| | - Darren Batey
- Diamond Light SourceHarwell Science and Innovation CampusFermi AveDidcotOX11 0DEUK
| | - Silvia Cipiccia
- Dept. of Medical Physics & Biomedical EngineeringUniversity College LondonMalet Place, Gower StreetLondonWC1E 6BTUK
| | - Matthias Stehle
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT)Engesserstr. 2076131KarlsruheGermany
| | - Ken L. Abel
- Institute of Chemical TechnologyUniversität LeipzigLinnéstr. 304103LeipzigGermany
| | - Roger Gläser
- Institute of Chemical TechnologyUniversität LeipzigLinnéstr. 304103LeipzigGermany
| | - Thomas L. Sheppard
- Institute for Chemical Technology and Polymer ChemistryKarlsruhe Institute of Technology (KIT)Engesserstr. 2076131KarlsruheGermany
- Institute of Catalysis Research and TechnologyKarlsruhe Institute of Technology (KIT)Hermann-von-Helmholtz-Platz 176344Eggenstein-LeopoldshafenGermany
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6
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Bhartiya A, Batey D, Cipiccia S, Shi X, Rau C, Botchway S, Yusuf M, Robinson IK. Correction to: X-ray ptychography imaging of human chromosomes after low-dose irradiation. Chromosome Res 2021; 29:419-420. [PMID: 34357486 PMCID: PMC8710439 DOI: 10.1007/s10577-021-09668-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Affiliation(s)
- Archana Bhartiya
- London Centre for Nanotechnology, University College, London, UK
- Department of Chemistry, University College, London, UK
- Research Complex at Harwell, Harwell Campus, Didcot, UK
| | - Darren Batey
- Diamond Light Source, Harwell Campus, Didcot, UK
| | | | - Xiaowen Shi
- Diamond Light Source, Harwell Campus, Didcot, UK
- Department of Physics, New Mexico State University, Las Cruces, NM, 88003, USA
| | | | | | - Mohammed Yusuf
- London Centre for Nanotechnology, University College, London, UK
- Research Complex at Harwell, Harwell Campus, Didcot, UK
- Centre for Regenerative Medicine and Stem Cell Research, Aga Khan University, Karachi, Pakistan
| | - Ian K Robinson
- London Centre for Nanotechnology, University College, London, UK.
- Research Complex at Harwell, Harwell Campus, Didcot, UK.
- Condensed Matter Physics and Materials Science Division, Brookhaven National Lab, Upton, NY, 11973, USA.
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7
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Bhartiya A, Batey D, Cipiccia S, Shi X, Rau C, Botchway S, Yusuf M, Robinson IK. X-ray Ptychography Imaging of Human Chromosomes After Low-dose Irradiation. Chromosome Res 2021; 29:107-126. [PMID: 33786705 PMCID: PMC8328905 DOI: 10.1007/s10577-021-09660-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/15/2021] [Accepted: 03/09/2021] [Indexed: 12/11/2022]
Abstract
Studies of the structural and functional role of chromosomes in cytogenetics have spanned more than 10 decades. In this work, we take advantage of the coherent X-rays available at the latest synchrotron sources to extract the individual masses of all 46 chromosomes of metaphase human B and T cells using hard X-ray ptychography. We have produced ‘X-ray karyotypes’ of both heavy metal–stained and unstained spreads to determine the gain or loss of genetic material upon low-level X-ray irradiation doses due to radiation damage. The experiments were performed at the I-13 beamline, Diamond Light Source, Didcot, UK, using the phase-sensitive X-ray ptychography method.
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Affiliation(s)
- Archana Bhartiya
- London Centre for Nanotechnology, University College, London, UK.,Department of Chemistry, University College, London, UK.,Research Complex at Harwell, Harwell Campus, Didcot, UK
| | - Darren Batey
- Diamond Light Source, Harwell Campus, Didcot, UK
| | | | - Xiaowen Shi
- Diamond Light Source, Harwell Campus, Didcot, UK.,Department of Physics, New Mexico State University, Las Cruces, NM, 88003, USA
| | | | | | - Mohammed Yusuf
- London Centre for Nanotechnology, University College, London, UK.,Research Complex at Harwell, Harwell Campus, Didcot, UK.,Centre for Regenerative Medicine and Stem Cell Research, Aga Khan University, Karachi, Pakistan
| | - Ian K Robinson
- London Centre for Nanotechnology, University College, London, UK. .,Research Complex at Harwell, Harwell Campus, Didcot, UK. .,Condensed Matter Physics and Materials Science Division, Brookhaven National Lab, Upton, NY, 11973, USA.
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8
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Estandarte AKC, Diao J, Llewellyn AV, Jnawali A, Heenan TMM, Daemi SR, Bailey JJ, Cipiccia S, Batey D, Shi X, Rau C, Brett DJL, Jervis R, Robinson IK, Shearing PR. Operando Bragg Coherent Diffraction Imaging of LiNi 0.8Mn 0.1Co 0.1O 2 Primary Particles within Commercially Printed NMC811 Electrode Sheets. ACS Nano 2021; 15:1321-1330. [PMID: 33355443 DOI: 10.1021/acsnano.0c08575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Due to complex degradation mechanisms, disparities between the theoretical and practical capacities of lithium-ion battery cathode materials persist. Specifically, Ni-rich chemistries such as LiNi0.8Mn0.1Co0.1O2 (or NMC811) are one of the most promising choices for automotive applications; however, they continue to suffer severe degradation during operation that is poorly understood, thus challenging to mitigate. Here we use operando Bragg coherent diffraction imaging for 4D analysis of these mechanisms by inspecting the individual crystals within primary particles at various states of charge (SoC). Although some crystals were relatively homogeneous, we consistently observed non-uniform distributions of inter- and intracrystal strain at all measured SoC. Pristine structures may already possess heterogeneities capable of triggering crystal splitting and subsequently particle cracking. During low-voltage charging (2.7-3.5 V), crystal splitting may still occur even during minimal bulk deintercalation activity; and during discharging, rotational effects within parallel domains appear to be the precursor for the nucleation of screw dislocations at the crystal core. Ultimately, this discovery of the central role of crystal grain splitting in the charge/discharge dynamics may have ramifications across length scales that affect macroscopic performance loss during real-world battery operation.
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Affiliation(s)
- Ana Katrina C Estandarte
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | - Jiecheng Diao
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Alice V Llewellyn
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
| | - Anmol Jnawali
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | - Thomas M M Heenan
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
| | - Sohrab R Daemi
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
| | - Josh J Bailey
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
| | | | - Darren Batey
- Diamond Light Source, Didcot, Oxon OX11 0DE, United Kingdom
| | - Xiaowen Shi
- Diamond Light Source, Didcot, Oxon OX11 0DE, United Kingdom
| | - Christoph Rau
- Diamond Light Source, Didcot, Oxon OX11 0DE, United Kingdom
| | - Dan J L Brett
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
| | - Rhodri Jervis
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
| | - Ian K Robinson
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
- Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Paul R Shearing
- Electrochemical Innovation Lab, Department of Chemical Engineering, University College London, Torrington Place, London WC1E 7JE, United Kingdom
- The Faraday Institution, Quad One, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0RA, United Kingdom
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Brun F, Di Trapani V, Batey D, Cipiccia S, Rau C. Edge-subtraction X-ray ptychographic imaging with pink beam synchrotron radiation and a single photon-counting detector. Sci Rep 2020; 10:6526. [PMID: 32300125 PMCID: PMC7162849 DOI: 10.1038/s41598-020-63161-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/16/2020] [Indexed: 11/09/2022] Open
Abstract
We present here a new method of performing X-ray edge-subtraction ptychographic imaging by combining multiple harmonics from an undulator synchtrotron source and an energy discriminating photon counting detector. Conventionally, monochromatic far-field X-ray ptychography is used to perform edge subtraction through the use of multiple monochromatic energy scans to obtain spectral information for a variety of applications. Here, we use directly the undulator spectrum from a synchrotron source, selecting two separate harmonics post sample using the Pixirad-1/Pixie-III detector. The result is two monochromatic images, above and below an absorption edge of interest. The proposed method is applied to obtain Au L-edge subtraction imaging of a Au-Ni grid test sample. The Au L-edge subtraction is particularly relevant for the identification of gold nanoparticles for biomedical applications. Switching the energy scan mechanism from a mechanical monochromator to an electronic detector threshold allows for faster spectral data collection with improved stability.
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Affiliation(s)
- Francesco Brun
- Department of Engineering and Architecture, University of Trieste, Trieste, Italy. .,National Institute for Nuclear Physics (INFN) - Trieste division, Trieste, Italy.
| | - Vittorio Di Trapani
- Department of Physical Sciences, Earth and Environment, University of Siena, Siena, Italy.,National Institute for Nuclear Physics (INFN) - Pisa division, Pisa, Italy
| | - Darren Batey
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0QX, UK
| | - Silvia Cipiccia
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0QX, UK
| | - Christoph Rau
- Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0QX, UK
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10
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Seiboth F, Kahnt M, Lyubomirskiy M, Seyrich M, Wittwer F, Ullsperger T, Nolte S, Batey D, Rau C, Schroer CG. Refractive hard x-ray vortex phase plates. Opt Lett 2019; 44:4622-4625. [PMID: 31517948 DOI: 10.1364/ol.44.004622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 06/21/2019] [Indexed: 06/10/2023]
Abstract
In this Letter, we report on the creation of hard x-ray beams carrying orbital angular momentum of topological charge -ℏ and -3ℏ at a photon energy of 8.2 keV via spiral phase plates made out of fused silica by ultrashort-pulsed laser ablation. The phase plates feature a smooth phase ramp with a 0.5 μm nominal step height and a surface roughness of 0.5 μm. The measured vortex beams show submicrometer-sized donut rings and agree well with numerical modeling. Fused silica phase plates are potentially suited to manipulate the electromagnetic field in highly intense x-ray beams at x-ray free-electron laser sources.
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11
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Li P, Batey D, Rodenburg J. An X-ray ptycho-tomography model of `Seeing order in ``amorphous'' materials'. Ultramicroscopy 2019; 203:88-94. [PMID: 30773416 DOI: 10.1016/j.ultramic.2019.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/29/2019] [Accepted: 02/06/2019] [Indexed: 10/27/2022]
Abstract
The nature of the atomic structure of many non-crystalline materials remains a long-standing open question. We use X-ray scattering to model electron images of amorphous materials, where the analogue 'atoms' consist of 1 μm diameter glass beads. The beads form a substantially random close-packed structure, but are partially ordered in places. X-ray ptycho-tomography reveals the exact position of the beads in 3D and so can be used to compare the modelled electron image with full knowledge of the underlying real structure. Using this, we repeat an experiment reported by Archie Howie and colleagues in 1978 that sought to test for real structure in bright-field electron images of amorphous materials; we demonstrate the validity of the technique, at least in the case of the resolution of the microscopes available at that time and the first Born approximation. We also illustrate how extremely demanding it would have been to infer 3D structure of amorphous material from pairs of stereoscopic images obtained with the same experimental kit: an approach that Archie proposed in the 1970s. We briefly discuss the possibility of using electron ptycho-tomography to solve the amorphous structure problem.
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Affiliation(s)
- Peng Li
- Department of Electronics and Electrical Engineering, University of Sheffield, North Campus, Broad Lane, Sheffield, S1 3JD, UK
| | - Darren Batey
- Department of Electronics and Electrical Engineering, University of Sheffield, North Campus, Broad Lane, Sheffield, S1 3JD, UK
| | - John Rodenburg
- Department of Electronics and Electrical Engineering, University of Sheffield, North Campus, Broad Lane, Sheffield, S1 3JD, UK.
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12
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Abstract
Recent advances in ptychographic imaging have shown how the technique extends naturally to mixed state experiments, for example when the illuminating radiation is partially coherent or when the object being imaged is laterally vibrating. To date, experiments using this mixed-state form of ptychography have relied on decomposition of the illumination 'probe' into multiple modes. In this paper we demonstrate, for the first time, ptychographic imaging with the simultaneous presence of both multiple probe and multiple object states. Our results prompt a discussion of uniqueness in the reconstructed images, and we show mathematically how ambiguities can arise. This leads us to extend the reconstruction process to include additional constraints that break these ambiguities, allowing interpretation of mixed object states that are not orthogonal.
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Abstract
AIM To establish a clinically efficient, cost-effective quality assurance programme as part of a routine retinopathy screening service. METHODS The operation of a quality assurance system as part of an ongoing retinal screening service is described. A random selection of 12% of images of all people reported to have retinopathy and of 2% reported to have no retinopathy are re-graded by a consultant ophthalmologist. Entry of the two sets of data into a purpose-designed excel spreadsheet allows automated calculation of sensitivity and specificity. RESULTS The results of quality assurance from August 2001 to July 2003 are reported. Out of 8351 screening episodes, 498 were re-examined. Of the 62 cases identified by the ophthalmologist as having referable retinopathy, four false negatives for detection were identified. Three of these had been assigned to early re-screening by the retinal screener but were still regarded as false negative by the parameters of the quality assurance system. The sensitivity and specificity for detection of sight-threatening retinopathy were 93.5% (95% CI = 84.3-98.2%) and 97.8% (95% CI = 95.8-98.9%), respectively. CONCLUSION A robust and cost-effective system has been developed to allow monitoring of performance of routine retinal screening which may be extended to meet current national recommendations.
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Affiliation(s)
- C S Arun
- Newcastle Diabetes Centre, Newcastle upon Tyne, UK
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