Journal of Applied Crystallography最新文献

{"title":"<i>mcstas_gisans</i>: combining ray tracing with the distorted-wave Born approximation using <i>McStas</i> and <i>BornAgain</i> for virtual GISANS experiments.","authors":"Milán Klausz, Artur Glavic, Sebastian Köhler, Thomas Arnold, Nicolò Paracini, Philipp Gutfreund, Marité Cárdenas, Max Wolff, Tommy Nylander","doi":"10.1107/S160057672600213X","DOIUrl":"10.1107/S160057672600213X","url":null,"abstract":"<p><p>The <i>mcstas_gisans</i> framework is a collection of Python scripts and modules to facilitate the simulation of grazing-incidence small-angle neutron scattering (GISANS) experiments. This approach combines <i>McStas</i> instrument simulation with <i>BornAgain</i> sample modeling capabilities. The Monte Carlo Particle Lists format for particle trajectory allows exchange between simulations that enables seamless transition from instrument modeling to sample scattering analysis. The Python-based processing utilities handle data transformation, scaling to virtual experiment times for absolute intensities, and visualization. The required software environment is managed through Conda, ensuring reproducible deployments across platforms. This integrated approach facilitates accurate simulation and analysis and enables the comparison of the GISANS capability of different neutron scattering instruments.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 3","pages":"827-836"},"PeriodicalIF":2.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13224798/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148149877","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}

{"title":"Approximate resolution convolution function for fitting a dispersion gap measured on a triple-axis spectrometer.","authors":"Emma Y Lenander, Silas B Schack, Kim Lefmann, Henrik M Rønnow","doi":"10.1107/S1600576726002049","DOIUrl":"10.1107/S1600576726002049","url":null,"abstract":"<p><p>We present an analytical convoluted gap function for fitting dispersion gaps measured on a triple-axis spectrometer (TAS). At the gap, the instrumental resolution skews the signal, producing a high-energy tail that complicates fitting. Our function assumes an instrumental <i>Q</i> resolution with two equal wide directions and one narrow direction (typical of focused TAS instruments) and a parabolic dispersion at the gap, which is exact for quadratic and accurate for linear dispersions if the resolution is moderate. We demonstrate that our function outperforms previous methods of fitting a gap by giving a better fit and more accurate gap determination. Here, the antiferromagnetically gapped material MnF₂ is simulated in a double-focusing TAS instrument. We also tested our function on experimental data on MnF₂ from a TAS-like instrument, where we reproduced the gap size from previous accurate measurements determined experimentally. The function is simple to implement and converges reliably, and we recommend its use for future gap fitting on TAS data.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 3","pages":"783-798"},"PeriodicalIF":2.8,"publicationDate":"2026-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13224810/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148149890","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}

{"title":"Characterization of laser powder bed fusion metal samples using Bragg edge neutron transmission analysis.","authors":"Matilde Dematteis, Luisa Vigorelli, Francesco Grazzi, Donato Orlandi, Daniele Cortis, Matteo Busi, Marco Costa","doi":"10.1107/S1600576726001482","DOIUrl":"10.1107/S1600576726001482","url":null,"abstract":"<p><p>Bragg edge neutron transmission analysis is a non-destructive technique that can be used for the investigation of properties of crystalline solids, such as microstructure, texture, strain or defects. In this work, Bragg edge imaging is applied to characterize additively manufactured metal samples produced via powder bed fusion-laser-based, featuring an innovative star-shaped geometry. This process can induce microstructural inhomogeneities within the material, thereby compromising the mechanical integrity of the final component. For this reason, a comprehensive understanding of the manufacturing process is essential to identify optimal operational parameters. Because of the lack of non-invasive techniques allowing an in-depth study of the microstructure of these samples, Bragg edge imaging is applied for providing detailed quantitative information on the manufacturing process. In this context, the final aim of this work is to investigate how the production process influences the final manufactured components. To study these effects, three different additively manufactured samples made of different metal alloys have been characterized by Bragg edge analysis. Characterization of elastic lattice strain, density of crystallographic defects and texture reveals significant discrepancies between the samples and their respective starting powders. These findings elucidate the various effects induced by the manufacturing process, which alters the crystalline structure of the metal and introduces anisotropy, potentially leading to mechanical failure of the components.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"357-368"},"PeriodicalIF":2.8,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060452/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645137","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}

{"title":"<i>PyExtal</i>: a Python package for quantitative convergent-beam electron diffraction.","authors":"Hsu-Chih Ni, Robert Busch, Jian-Min Zuo","doi":"10.1107/S1600576726001469","DOIUrl":"10.1107/S1600576726001469","url":null,"abstract":"<p><p>Quantitative convergent-beam electron diffraction (QCBED) enables the measurement of structure factors and other structural parameters with high accuracy using dynamical diffraction theory. To do this, rigorous diffraction simulations and iterative intensity refinement are required. We have developed <i>PyExtal</i>, a Python-based software package for QCBED. <i>PyExtal</i> supports refinement of both small- and large-unit-cell crystals through automated computation workflows and flexible data handling of convergent-beam electron diffraction (CBED) and large-angle CBED patterns. The performance of <i>PyExtal</i> is demonstrated by using silicon and yttrium iron garnet as benchmark systems, with refined silicon structure factors showing excellent agreement with previous experimental results. As a computational platform, <i>PyExtal</i> provides a direct basis for experimental mapping of electron charge density in crystals and facilitates broader applications of dynamical-diffraction-based quantitative crystallographic analysis.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"687-699"},"PeriodicalIF":2.8,"publicationDate":"2026-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060613/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147644974","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}

{"title":"<i>Vitess 3.8</i>: a modernized framework for Monte Carlo neutron tracing simulations.","authors":"José Ignacio Robledo, Nicoló Violini, Fabian Beule, Jorg Voigt, Paul Zakalek, Klaus Lieutenant","doi":"10.1107/S1600576726001093","DOIUrl":"10.1107/S1600576726001093","url":null,"abstract":"<p><p><i>VITESS</i> is a modular Monte Carlo simulation package for modeling and optimizing neutron scattering instruments through ray tracing of neutrons. The latest release, <i>VITESS 3.8</i>, introduces major advances in functionality and software infrastructure. They include new source modules for integrating external moderator simulations and artificial-intelligence-based flux modeling, as well as prism for beam deflection and crystalline material simulations via <i>NCrystal</i>. Existing modules have been extended to support spin-dependent scattering, advanced monochromator motions and improved polarization handling. The update also includes a Git-based continuous integration system ensuring reproducibility.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"678-686"},"PeriodicalIF":2.8,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060619/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645018","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}

{"title":"Towards improving the PF1B beamline <i>McStas</i> model through simulations of a beam characterization experiment.","authors":"Clément Desalme, Jason Pioquinto, Valentin Czamler, Stefan Baeßler, Kazimierz Bodek, Valery Nesvizhevsky, Dagmara Rozpędzik, Katharina Schreiner, Torsten Soldner","doi":"10.1107/S1600576726001639","DOIUrl":"10.1107/S1600576726001639","url":null,"abstract":"<p><p>The PF1B instrument at the Institut Laue-Langevin (ILL) delivers a high-flux cold neutron beam through the H113 neutron guide. In the years following the characterization published with the highest polarization in 2006, radiation-damaged sections of the guide have been replaced and the in-pile part has been upgraded. In 2024, a new experiment using time of flight was performed to characterize the instrument. Simulations intended to reproduce this experiment have been performed with <i>McStas</i> using an already existing model of H113. In this work, we present a first comparison of experimental and simulated time-of-flight spectra, showing overall good agreement but discrepancies which might be reduced by adjusting the existing <i>McStas</i> model. Parameter optimization is ongoing, aiming at a more accurate description that would serve for future experiments on PF1B.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"404-409"},"PeriodicalIF":2.8,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060404/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645367","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}

{"title":"<i>RAPIDviewer</i>: an <i>ImageJ</i> script for visualization and analysis of indexed electron diffraction patterns of cubic materials.","authors":"Thomas E Weirich","doi":"10.1107/S1600576726002086","DOIUrl":"10.1107/S1600576726002086","url":null,"abstract":"<p><p><i>RAPIDviewer</i> is a newly developed <i>ImageJ</i> macro script that addresses the limitations of the indexing program <i>RAPID</i> (which enables the indexing of zone-axis electron diffraction patterns from cubic materials) by generating graphical overlays on the experimental patterns, including configurable spot and Kikuchi line drawings. Additional features include orientation sketches, inverse-pole-figure markers and an option for <i>VESTA</i> file export. Examples utilizing selected-area electron diffraction patterns from an austenitic steel, an M₂₃C₆ precipitate and an aluminium alloy illustrate the features of the program.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"673-677"},"PeriodicalIF":2.8,"publicationDate":"2026-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060617/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147644903","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}

{"title":"Detector alignment for X-ray crystallography using <i>Millepede-II</i>.","authors":"Thomas A White","doi":"10.1107/S1600576726001287","DOIUrl":"10.1107/S1600576726001287","url":null,"abstract":"<p><p>I describe a method for accurately refining the geometrical parameters of segmented X-ray area detectors on the basis of serial crystallography data, using 'Millepede' - an algorithm created for a very similar problem in high-energy physics. The Millepede method for serial crystallography builds on the approach of Brewster <i>et al.</i> [<i>Acta Cryst.</i> (2018), D<b>74</b>, 877-894], in which the detector parameters are refined simultaneously with the parameters for each individual crystal. This accounts for the mutual dependency between the parameters and thereby avoids the bias and slow convergence problems that have afflicted older approaches in which the deviations between observed and calculated Bragg peak positions were taken directly as the updates for the detector panel positions. The Millepede method uses the special structure of the least-squares normal equations to reduce them to a much smaller form that can be solved very quickly, even compared with the sparse matrix methods used previously. This makes it practical to refine the detector geometry frequently and thereby maintain accurate calibration without specialized alignment campaigns. Tilts of detector panels out of the plane can be reliably refined, as can the overall distance of the detector in the beam direction. With a simulated test case, the new method produced panel shifts within 7% of the correct values with only one iteration, and produced almost exactly correct shifts after a second iteration. A simulated out-of-plane panel rotation was correctly determined to within 0.001°. Applied to experimental data from an X-ray free-electron laser, the method increased the indexable fraction of frames from 30% to 91% in a single iteration, and to 96% after two further iterations. Computing the geometry updates on the basis of 2060 crystals took only 0.819 s on desktop computing hardware, including the time taken to read the required data from disk. The scaling was found to be very close to linear for up to 100 980 sets of crystal parameters, which took only 78.2 s to process under the same conditions. The method has been applied as part of a real-time feedback system at a synchrotron radiation beamline, in which an out-of-plane detector tilt of 0.04° was detected and corrected. Possible further applications are also described here.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"594-608"},"PeriodicalIF":2.8,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060621/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645186","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}

{"title":"New <i>para</i>-hydrogen cold neutron source at the Budapest Research Reactor: Monte Carlo simulations.","authors":"Dmitrii Shapiro, Petr Konik, Mina Akhyani, Alexander Ioffe","doi":"10.1107/S1600576726001263","DOIUrl":"10.1107/S1600576726001263","url":null,"abstract":"<p><p>The planned upgrade of the neutron guide system at the Budapest Research Reactor (BRR) provides an opportunity to enhance the performance of its cold neutron source. In this work, two replacement concepts for the existing liquid hydrogen disk moderator are investigated: (i) a box-shaped <i>para</i>-hydrogen (pH₂) moderator and (ii) assemblies of low-dimensional (flat) pH₂ moderators. Both designs are optimized using the curve of full and optimal sample illumination method and through Monte Carlo simulations tailored to the BRR geometry and the thermal neutron distribution. The box pH₂ moderator is found to increase the cold neutron brightness by up to 2.2 times in the 3-7 Å wavelength range. Flat moderator assemblies, as either staircases or chessboards, provide an additional gain of about 20% at 2 Å, although their advantage diminishes at longer wavelengths due to the non-uniform thermal illumination of the reactor channel and the wavelength dependence of the optimal moderator length. These results demonstrate that pH₂ moderators, particularly in low-dimensional geometries, can substantially enhance the performance of the upgraded BRR cold neutron source, with the achievable gains largely limited by the thermal neutron distribution within the existing moderator channel.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"392-403"},"PeriodicalIF":2.8,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060473/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645269","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}

{"title":"Automation of Rietveld refinement through machine learning.","authors":"Suk Jin Mun, Yoonsoo Nam, Sungkyun Choi","doi":"10.1107/S1600576726001494","DOIUrl":"10.1107/S1600576726001494","url":null,"abstract":"<p><p>Rietveld refinement is a widely used technique for determining crystal structures from powder X-ray diffraction data. Despite its broad applicability, the refinement process often requires substantial manual effort and expert knowledge, which limits the pace of materials research. Here, we introduce a methodology based on convolutional neural networks that enables automated Rietveld refinement. A systematically generated training dataset, which incorporates diverse structural and profile parameters, allows the network to capture complex pattern-structure relationships effectively. A refined crystal structure is directly extracted from the experimental powder X-ray diffraction pattern in a single inference step. The approach is validated using benchmark datasets of CeO₂, Tb₂BaCoO₅ and PbSO₄, achieving reliability factors comparable to those obtained from conventional methods. This work establishes a generalizable methodology by providing valuable insights into the development of autonomous diffraction analysis, with the potential to accelerate materials discovery and characterization.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"59 Pt 2","pages":"564-577"},"PeriodicalIF":2.8,"publicationDate":"2026-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13060465/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645092","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}