Pub Date : 2023-06-01DOI: 10.1107/S1600576723003771
Ricardo Fernández, Gizo Bokuchava, Giovanni Bruno, Itziar Serrano-Muñoz, Gaspar González-Doncel
The peak broadening in neutron diffraction experiments on tensile specimens of pure Al (99.8%) and an Al-Mg alloy pre-deformed at different creep strains is analysed. These results are combined with the kernel angular misorientation of electron backscatter diffraction data from the creep-deformed microstructures. It is found that differently oriented grains possess different microstrains. These microstrains vary with creep strain in pure Al, but not in the Al-Mg alloy. It is proposed that this behaviour can explain the power-law breakdown in pure Al and the large creep strain observed in Al-Mg. The present findings further corroborate a description of the creep-induced dislocation structure as a fractal, predicated on previous work.
{"title":"On the dependence of creep-induced dislocation configurations on crystallographic orientation in pure Al and Al-Mg.","authors":"Ricardo Fernández, Gizo Bokuchava, Giovanni Bruno, Itziar Serrano-Muñoz, Gaspar González-Doncel","doi":"10.1107/S1600576723003771","DOIUrl":"https://doi.org/10.1107/S1600576723003771","url":null,"abstract":"<p><p>The peak broadening in neutron diffraction experiments on tensile specimens of pure Al (99.8%) and an Al-Mg alloy pre-deformed at different creep strains is analysed. These results are combined with the kernel angular misorientation of electron backscatter diffraction data from the creep-deformed microstructures. It is found that differently oriented grains possess different microstrains. These microstrains vary with creep strain in pure Al, but not in the Al-Mg alloy. It is proposed that this behaviour can explain the power-law breakdown in pure Al and the large creep strain observed in Al-Mg. The present findings further corroborate a description of the creep-induced dislocation structure as a fractal, predicated on previous work.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10241052/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9595269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An equiatomic nickel-titanium shape-memory alloy specimen subjected to a uniaxial tensile load undergoes a two-step phase transformation under stress, from austenite (A) to a rhombohedral phase (R) and further to martensite (M) variants. The pseudo-elasticity that goes accompanies the phase transformation induces spatial inhomogeneity. To unravel the spatial distribution of the phases, in situ X-ray diffraction analyses are performed while the sample is under tensile load. However, the diffraction spectra of the R phase, as well as the extent of potential martensite detwinning, are not known. A novel algorithm, based on a proper orthogonal decomposition and incorporating inequality constraints, is proposed in order to map out the different phases and simultaneously yield the missing diffraction spectral information. An experimental case study illustrates the methodology.
{"title":"Three-phase material mapping with incomplete X-ray diffraction spectral information.","authors":"Xuyang Chang, Karine Lavernhe-Taillard, Stéphane Roux, Olivier Hubert","doi":"10.1107/S160057672300331X","DOIUrl":"https://doi.org/10.1107/S160057672300331X","url":null,"abstract":"<p><p>An equiatomic nickel-titanium shape-memory alloy specimen subjected to a uniaxial tensile load undergoes a two-step phase transformation under stress, from austenite (A) to a rhombohedral phase (R) and further to martensite (M) variants. The pseudo-elasticity that goes accompanies the phase transformation induces spatial inhomogeneity. To unravel the spatial distribution of the phases, <i>in situ</i> X-ray diffraction analyses are performed while the sample is under tensile load. However, the diffraction spectra of the R phase, as well as the extent of potential martensite detwinning, are not known. A novel algorithm, based on a proper orthogonal decomposition and incorporating inequality constraints, is proposed in order to map out the different phases and simultaneously yield the missing diffraction spectral information. An experimental case study illustrates the methodology.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10241039/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9645106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1107/S1600576723002339
Martin Roelsgaard, Magnus Kløve, Rasmus Christensen, Andreas D Bertelsen, Nils L N Broge, Innokenty Kantor, Daniel Risskov Sørensen, Ann-Christin Dippel, Soham Banerjee, Martin V Zimmermann, Philipp Glaevecke, Olof Gutowski, Mads Ry Vogel Jørgensen, Bo Brummerstedt Iversen
Understanding the nucleation and growth mechanisms of nanocrystals under hydro- and solvothermal conditions is key to tailoring functional nanomaterials. High-energy and high-flux synchrotron radiation is ideal for characterization by powder X-ray diffraction and X-ray total scattering in real time. Different versions of batch-type cell reactors have been employed in this work, exploiting the robustness of polyimide-coated fused quartz tubes with an inner diameter of 0.7 mm, as they can withstand pressures up to 250 bar and temperatures up to 723 K for several hours. Reported here are recent developments of the in situ setups available for general users on the P21.1 beamline at PETRA III and the DanMAX beamline at MAX IV to study nucleation and growth phenomena in solvothermal synthesis. It is shown that data suitable for both reciprocal-space Rietveld refinement and direct-space pair distribution function refinement can be obtained on a timescale of 4 ms.
{"title":"A reactor for time-resolved X-ray studies of nucleation and growth during solvothermal synthesis.","authors":"Martin Roelsgaard, Magnus Kløve, Rasmus Christensen, Andreas D Bertelsen, Nils L N Broge, Innokenty Kantor, Daniel Risskov Sørensen, Ann-Christin Dippel, Soham Banerjee, Martin V Zimmermann, Philipp Glaevecke, Olof Gutowski, Mads Ry Vogel Jørgensen, Bo Brummerstedt Iversen","doi":"10.1107/S1600576723002339","DOIUrl":"https://doi.org/10.1107/S1600576723002339","url":null,"abstract":"<p><p>Understanding the nucleation and growth mechanisms of nanocrystals under hydro- and solvothermal conditions is key to tailoring functional nanomaterials. High-energy and high-flux synchrotron radiation is ideal for characterization by powder X-ray diffraction and X-ray total scattering in real time. Different versions of batch-type cell reactors have been employed in this work, exploiting the robustness of polyimide-coated fused quartz tubes with an inner diameter of 0.7 mm, as they can withstand pressures up to 250 bar and temperatures up to 723 K for several hours. Reported here are recent developments of the <i>in situ</i> setups available for general users on the P21.1 beamline at PETRA III and the DanMAX beamline at MAX IV to study nucleation and growth phenomena in solvothermal synthesis. It is shown that data suitable for both reciprocal-space Rietveld refinement and direct-space pair distribution function refinement can be obtained on a timescale of 4 ms.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10241040/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9589926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-12DOI: 10.1101/2022.11.23.517685
M. Vakili, Huijong Han, C. Schmidt, A. Wrona, M. Kloos, I. de Diego, K. Dörner, T. Geng, Chan Kim, F. Koua, D. Melo, M. Rappas, A. Round, E. Round, M. Sikorski, J. Valerio, T. Zhou, K. Lorenzen, J. Schulz
Time-resolved crystallography enabled the visualization of protein molecular motion during reaction. While light is commonly used to initiate reactions in time-resolved crystallography, only a small number of proteins can in fact be activated by light. However, many biological reactions can be triggered by the interaction of proteins with ligands. The sample delivery method presented here uses a mix-and-extrude approach based on 3D printed microchannels in conjunction with a micronozzle to study the dynamics of samples in viscous media that can be triggered by diffusive mixing. The device design allows for mixing of ligands and protein crystals in a time window of 2 to 20 seconds. The device characterization using a model system (fluorescence quenching of iq-mEmerald proteins by copper ions) demonstrated that ligand and protein crystals, each within the lipidic cubic phase, can be mixed efficiently. The potential use of this approach for time-resolved membrane protein crystallography to support in the development of new drugs is also discussed. Synopsis 3D printed mixing-HVE devices address time-resolved membrane protein crystallography challenges via compact dual-flow LCP injection.
{"title":"Mix-and-extrude: high-viscosity sample injection towards time-resolved protein crystallography","authors":"M. Vakili, Huijong Han, C. Schmidt, A. Wrona, M. Kloos, I. de Diego, K. Dörner, T. Geng, Chan Kim, F. Koua, D. Melo, M. Rappas, A. Round, E. Round, M. Sikorski, J. Valerio, T. Zhou, K. Lorenzen, J. Schulz","doi":"10.1101/2022.11.23.517685","DOIUrl":"https://doi.org/10.1101/2022.11.23.517685","url":null,"abstract":"Time-resolved crystallography enabled the visualization of protein molecular motion during reaction. While light is commonly used to initiate reactions in time-resolved crystallography, only a small number of proteins can in fact be activated by light. However, many biological reactions can be triggered by the interaction of proteins with ligands. The sample delivery method presented here uses a mix-and-extrude approach based on 3D printed microchannels in conjunction with a micronozzle to study the dynamics of samples in viscous media that can be triggered by diffusive mixing. The device design allows for mixing of ligands and protein crystals in a time window of 2 to 20 seconds. The device characterization using a model system (fluorescence quenching of iq-mEmerald proteins by copper ions) demonstrated that ligand and protein crystals, each within the lipidic cubic phase, can be mixed efficiently. The potential use of this approach for time-resolved membrane protein crystallography to support in the development of new drugs is also discussed. Synopsis 3D printed mixing-HVE devices address time-resolved membrane protein crystallography challenges via compact dual-flow LCP injection.","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49486907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1107/S1600576723001747
Nicholas Burns, Aly Rahemtulla, Scott Annett, Beatriz Moreno, Stefan Kycia
X-ray total scattering measurements are implemented using a digital flat-panel area detector in an inclined geometry and compared with the traditional geometry. The traditional geometry is defined here by the incident X-ray beam impinging on and normal to the center-most pixel of a detector. The inclined geometry is defined here by a detector at a pitch angle α, set to 15° in this case, bisected by the vertical scattering plane. The detector is positioned such that the incident X-ray beam strikes the pixels along the bottom edge and 90° scattered X-rays impinge on the pixels along the top edge. The geometric attributes of the inclined geometry translate into multiple benefits, such as an extension of the measurable scattering range to 90°, a 47% increase in the accessible magnitudes of the reciprocal-space vector Q and a leveling of the dynamic range in the measured total scattering pattern. As a result, a sixfold improvement in signal-to-noise ratios is observed at higher scattering angles, enabling up to a 36-fold reduction in acquisition time. Additionally, the extent of applied modification functions is reduced, decreasing the magnitude of termination ripples and improving the real-space resolution of the pair distribution function G(r). Taken all together, these factors indicate that the inclined geometry produces higher quality data than the traditional geometry, usable for simultaneous Rietveld refinement and total scattering studies.
{"title":"An inclined detector geometry for improved X-ray total scattering measurements.","authors":"Nicholas Burns, Aly Rahemtulla, Scott Annett, Beatriz Moreno, Stefan Kycia","doi":"10.1107/S1600576723001747","DOIUrl":"https://doi.org/10.1107/S1600576723001747","url":null,"abstract":"<p><p>X-ray total scattering measurements are implemented using a digital flat-panel area detector in an inclined geometry and compared with the traditional geometry. The traditional geometry is defined here by the incident X-ray beam impinging on and normal to the center-most pixel of a detector. The inclined geometry is defined here by a detector at a pitch angle α, set to 15° in this case, bisected by the vertical scattering plane. The detector is positioned such that the incident X-ray beam strikes the pixels along the bottom edge and 90° scattered X-rays impinge on the pixels along the top edge. The geometric attributes of the inclined geometry translate into multiple benefits, such as an extension of the measurable scattering range to 90°, a 47% increase in the accessible magnitudes of the reciprocal-space vector <i>Q</i> and a leveling of the dynamic range in the measured total scattering pattern. As a result, a sixfold improvement in signal-to-noise ratios is observed at higher scattering angles, enabling up to a 36-fold reduction in acquisition time. Additionally, the extent of applied modification functions is reduced, decreasing the magnitude of termination ripples and improving the real-space resolution of the pair distribution function <i>G</i>(<i>r</i>). Taken all together, these factors indicate that the inclined geometry produces higher quality data than the traditional geometry, usable for simultaneous Rietveld refinement and total scattering studies.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10077857/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9641101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Trigonal-prismatic coordinated transition metal dichalcogenides (TMDCs) are formed from stacked (chalcogen)-(transition metal)-(chalcogen) triple layers, where the chemical bond is covalent within the triple layers and van der Waals (vdW) forces are effective between the layers. Bonding is at the origin of the great interest in these compounds, which are used as 2D materials in applications such as catalysis, electronics, photoelectronics, sensors, batteries and thermoelectricity. This paper addresses the issue of modelling the structural disorder in multilayer TMDCs. The structural model takes into account stacking faults, correlated displacement of atoms and average crystallite size/shape, and is assessed by simulation of the X-ray diffraction pattern and fitting to the experimental data relative to a powdered sample of MoS2 exfoliated and restacked via lithiation. From fitting, an average crystallite size of about 50 Å, nearly spherical crystallites and a definite probability of deviation from the fully eclipsed atomic arrangement present in the ordered structure are determined. The increased interlayer distance and correlated intralayer and interlayer atomic displacement are attributed to the presence of lithium intercalated in the vdW gap between triple layers (Li/Mo molar ratio of about 0.06). The model holds for the whole class of trigonal-prismatic coordinated TMDCs, and is suitably flexible to take into account different preparation routes.
{"title":"Modelling the structural disorder in trigonal-prismatic coordinated transition metal dichalcogenides.","authors":"Federica Ursi, Simone Virga, Candida Pipitone, Alessandra Sanson, Alessandro Longo, Francesco Giannici, Antonino Martorana","doi":"10.1107/S1600576723001589","DOIUrl":"https://doi.org/10.1107/S1600576723001589","url":null,"abstract":"<p><p>Trigonal-prismatic coordinated transition metal dichalcogenides (TMDCs) are formed from stacked (chalcogen)-(transition metal)-(chalcogen) triple layers, where the chemical bond is covalent within the triple layers and van der Waals (vdW) forces are effective between the layers. Bonding is at the origin of the great interest in these compounds, which are used as 2D materials in applications such as catalysis, electronics, photoelectronics, sensors, batteries and thermoelectricity. This paper addresses the issue of modelling the structural disorder in multilayer TMDCs. The structural model takes into account stacking faults, correlated displacement of atoms and average crystallite size/shape, and is assessed by simulation of the X-ray diffraction pattern and fitting to the experimental data relative to a powdered sample of MoS<sub>2</sub> exfoliated and restacked via lithiation. From fitting, an average crystallite size of about 50 Å, nearly spherical crystallites and a definite probability of deviation from the fully eclipsed atomic arrangement present in the ordered structure are determined. The increased interlayer distance and correlated intralayer and interlayer atomic displacement are attributed to the presence of lithium intercalated in the vdW gap between triple layers (Li/Mo molar ratio of about 0.06). The model holds for the whole class of trigonal-prismatic coordinated TMDCs, and is suitably flexible to take into account different preparation routes.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10077858/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9271762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1107/S1600576722011001
Axel Henningsson, Stephen A Hall
An open source Python package named xrd_simulator, capable of simulating geometrical interactions between a monochromatic X-ray beam and a polycrystalline microstructure, is described and demonstrated. The software can simulate arbitrary intragranular lattice variations of single crystals embedded within a multiphase 3D aggregate by making use of a tetrahedral mesh representation where each element holds an independent lattice. By approximating the X-ray beam as an arbitrary convex polyhedral region in space and letting the sample be moved continuously through arbitrary rigid motions, data from standard and non-standard measurement sequences can be simulated. This implementation is made possible through analytical solutions to a modified, time-dependent version of the Laue equations. The software, which primarily targets three-dimensional X-ray diffraction microscopy (high-energy X-ray diffraction microscopy) type experiments, enables the numerical exploration of which sample quantities can and cannot be reconstructed for a given acquisition scheme. Similarly, xrd_simulator targets investigations of different measurement sequences in relation to optimizing both experimental run times and sampling.
{"title":"<i>xrd_simulator</i>: 3D X-ray diffraction simulation software supporting 3D polycrystalline microstructure morphology descriptions.","authors":"Axel Henningsson, Stephen A Hall","doi":"10.1107/S1600576722011001","DOIUrl":"https://doi.org/10.1107/S1600576722011001","url":null,"abstract":"<p><p>An open source Python package named <i>xrd_simulator</i>, capable of simulating geometrical interactions between a monochromatic X-ray beam and a polycrystalline microstructure, is described and demonstrated. The software can simulate arbitrary intragranular lattice variations of single crystals embedded within a multiphase 3D aggregate by making use of a tetrahedral mesh representation where each element holds an independent lattice. By approximating the X-ray beam as an arbitrary convex polyhedral region in space and letting the sample be moved continuously through arbitrary rigid motions, data from standard and non-standard measurement sequences can be simulated. This implementation is made possible through analytical solutions to a modified, time-dependent version of the Laue equations. The software, which primarily targets three-dimensional X-ray diffraction microscopy (high-energy X-ray diffraction microscopy) type experiments, enables the numerical exploration of which sample quantities can and cannot be reconstructed for a given acquisition scheme. Similarly, <i>xrd_simulator</i> targets investigations of different measurement sequences in relation to optimizing both experimental run times and sampling.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9901924/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9600701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1107/S160057672201069X
Olivier Thomas, Ismail Cevdet Noyan
Various formulations are compared which describe diffraction from ultra-thin single-crystal films in the symmetric scattering configuration, showing that, for this thickness range, several implicit assumptions in these formulations are no longer satisfied. Consequently, the position, integrated intensity and integral breadth of a diffraction peak cannot be related to the lattice spacing of the material or the number of unit cells along the diffraction vector using traditional analysis methods. Some simple equations are proposed to obtain the correct values of these parameters for this specific sample/diffraction geometry combination. More generally, the development of rigorous formalisms for analyzing diffraction from nanocrystals is proposed.
{"title":"Kinematic scattering by nanocrystals.","authors":"Olivier Thomas, Ismail Cevdet Noyan","doi":"10.1107/S160057672201069X","DOIUrl":"https://doi.org/10.1107/S160057672201069X","url":null,"abstract":"<p><p>Various formulations are compared which describe diffraction from ultra-thin single-crystal films in the symmetric scattering configuration, showing that, for this thickness range, several implicit assumptions in these formulations are no longer satisfied. Consequently, the position, integrated intensity and integral breadth of a diffraction peak cannot be related to the lattice spacing of the material or the number of unit cells along the diffraction vector using traditional analysis methods. Some simple equations are proposed to obtain the correct values of these parameters for this specific sample/diffraction geometry combination. More generally, the development of rigorous formalisms for analyzing diffraction from nanocrystals is proposed.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9901918/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10704100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-01DOI: 10.1107/S1600576722011360
Benjamin S Hulbert, Waltraud M Kriven
The effect of small changes in the speci-men-to-detector distance on the unit-cell parameters is examined for synchrotron powder diffraction in Debye-Scherrer (transmission) geometry with a flat area detector. An analytical correction equation is proposed to fix the shift in 2θ values due to speci-men capillary displacement. This equation does not require the use of an internal reference material, is applied during the Rietveld refinement step, and is analogous to the speci-men-displacement correction equations for Bragg-Brentano and curved-detector Debye-Scherrer geometry experiments, but has a different functional form. The 2θ correction equation is compared with another speci-men-displacement correction based on the use of an internal reference material in which new integration and calibration parameters of area-detector images are determined. Example data sets showing the effect of a 3.3 mm speci-men displacement on the unit-cell parameters for 25°C CeO2, including both types of displacement correction, are described. These experiments were performed at powder X-ray diffraction beamlines at the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.
{"title":"Specimen-displacement correction for powder X-ray diffraction in Debye-Scherrer geometry with a flat area detector.","authors":"Benjamin S Hulbert, Waltraud M Kriven","doi":"10.1107/S1600576722011360","DOIUrl":"https://doi.org/10.1107/S1600576722011360","url":null,"abstract":"<p><p>The effect of small changes in the speci-men-to-detector distance on the unit-cell parameters is examined for synchrotron powder diffraction in Debye-Scherrer (transmission) geometry with a flat area detector. An analytical correction equation is proposed to fix the shift in 2θ values due to speci-men capillary displacement. This equation does not require the use of an internal reference material, is applied during the Rietveld refinement step, and is analogous to the speci-men-displacement correction equations for Bragg-Brentano and curved-detector Debye-Scherrer geometry experiments, but has a different functional form. The 2θ correction equation is compared with another speci-men-displacement correction based on the use of an internal reference material in which new integration and calibration parameters of area-detector images are determined. Example data sets showing the effect of a 3.3 mm speci-men displacement on the unit-cell parameters for 25°C CeO<sub>2</sub>, including both types of displacement correction, are described. These experiments were performed at powder X-ray diffraction beamlines at the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9901925/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9263079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.1107/S1600576722010214
Haixing Fang, Wolfgang Ludwig, Pierre Lhuissier
X-ray-based non-destructive 3D grain mapping techniques are well established at synchrotron facilities. To facilitate everyday access to grain mapping instruments, laboratory diffraction contrast tomography (LabDCT), using a laboratory-based conical polychromatic X-ray beam, has been developed and commercialized. Yet the currently available LabDCT grain reconstruction methods are either ill-suited for handling a large number of grains or require a commercial licence bound to a specific instrument. To promote the availability of LabDCT, grain reconstruction methods have been developed with multiple reconstruction algorithms based on both forward and back calculations. The different algorithms are presented in detail and their efficient implementation using parallel computing is described. The performance of different reconstruction methods is assessed on synthetic data. The code to implement all the described algorithms has been made publicly accessible with the intention of fostering the development of grain mapping techniques on widely available laboratory instruments.
基于 X 射线的非破坏性三维晶粒测绘技术已在同步加速器设施中得到广泛应用。为了方便人们日常使用晶粒测绘仪器,利用实验室锥形多色 X 射线束的实验室衍射对比层析成像技术(LabDCT)已经开发出来并实现了商业化。然而,目前可用的 LabDCT 晶粒重建方法要么不适合处理大量晶粒,要么需要与特定仪器绑定的商业许可。为了提高 LabDCT 的可用性,我们开发了基于正向和反向计算的多种重建算法的谷物重建方法。本文详细介绍了不同的算法,并介绍了利用并行计算有效实现这些算法的方法。在合成数据上对不同重建方法的性能进行了评估。实现所有所述算法的代码已经公开,目的是在广泛可用的实验室仪器上促进谷物绘图技术的发展。
{"title":"Reconstruction algorithms for grain mapping by laboratory X-ray diffraction contrast tomography.","authors":"Haixing Fang, Wolfgang Ludwig, Pierre Lhuissier","doi":"10.1107/S1600576722010214","DOIUrl":"10.1107/S1600576722010214","url":null,"abstract":"<p><p>X-ray-based non-destructive 3D grain mapping techniques are well established at synchrotron facilities. To facilitate everyday access to grain mapping instruments, laboratory diffraction contrast tomography (LabDCT), using a laboratory-based conical polychromatic X-ray beam, has been developed and commercialized. Yet the currently available LabDCT grain reconstruction methods are either ill-suited for handling a large number of grains or require a commercial licence bound to a specific instrument. To promote the availability of LabDCT, grain reconstruction methods have been developed with multiple reconstruction algorithms based on both forward and back calculations. The different algorithms are presented in detail and their efficient implementation using parallel computing is described. The performance of different reconstruction methods is assessed on synthetic data. The code to implement all the described algorithms has been made publicly accessible with the intention of fostering the development of grain mapping techniques on widely available laboratory instruments.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":null,"pages":null},"PeriodicalIF":6.1,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9721336/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10430242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}