Journal of Applied Crystallography最新文献

{"title":"Cold versus thermal neutron source: assessment of performance of the KWS-2 SANS diffractometer of the Jülich Centre for Neutron Science at the FRM II reactor.","authors":"Aurel Radulescu, Ralf Biehl, Aristeidis Papagiannopoulos","doi":"10.1107/S1600576725006491","DOIUrl":"10.1107/S1600576725006491","url":null,"abstract":"<p><p>The small-angle neutron scattering (SANS) diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Zentrum, Garching, Germany, is a high-flux instrument based on the combination of a specially developed neutron guide system, which allows delivery of a high neutron intensity for a wide wavelength range λ between 2.8 and 20 Å to the instrument, and a versatile velocity selector, which allows an easy choice of wavelength spread Δλ/λ depending on whether the specific scientific goal is either improved resolution, <i>i.e.</i> Δλ/λ = 10%, or high intensity, <i>i.e.</i> Δλ/λ = 20%. Here we report an evaluation of KWS-2 performance by measurements and <i>McStas</i> simulations under the condition that only the thermal neutron source (TNS) is available at the FRM II reactor. According to the simulations, a flux decrease by a factor of 2.5 for λ = 2.8-3 Å and by a factor of 10 for λ ≥ 4.5 Å is expected if the reactor is operated only with the TNS compared with the established performance with cold neutrons provided by the cold neutron source. The flux decrease in TNS operation can be mitigated for λ ≥ 4.5 Å by using a low-resolution velocity selector which provides Δλ/λ = 20% for standard positioning and Δλ/λ = 35% when tilted at an angle ξ_i = -10° to the beam axis. According to measurements, this degradation of resolution for increasing intensity does not seem to be critical for the structural characterization of small biological morphologies, which would be one of the most investigated topics if only thermal neutrons were available at the FRM II. However, ordering effects in the scattering characteristics of lamellar soft or biophysical systems are barely observable when the resolution is relaxed to Δλ/λ ≥ 20%, which defines the performance limits of the experimental approach. Furthermore, by using MgF₂ focusing lenses when working with large samples, an intensity gain on the sample of up to 12-fold is achieved while keeping the same <i>Q</i> _min resolution as with the standard pinhole mode, restoring the flux loss expected with thermal neutrons for λ ≥ 7 Å.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1582-1594"},"PeriodicalIF":2.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502878/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251095","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":"Deconvoluting Patterson.","authors":"Bernhard Rupp","doi":"10.1107/S1600576725006569","DOIUrl":"10.1107/S1600576725006569","url":null,"abstract":"<p><p>The Patterson function, <i>P</i>(<b>u</b>), is useful in many crystallographic applications, including experimental phasing, molecular replacement and the exploration of non-crystallographic symmetries. <i>P</i>(<b>u</b>) is defined as the autocorrelation of the electron density. Autocorrelation is often an unfamiliar concept for students of biological or biomedical fields of study. I present a freely available animated <i>PowerPoint</i> slide deck featuring 1D electron density plots and the corresponding autocorrelation resulting in the Patterson function that is readily interpretable as an interatomic distance map. The animation makes it easy to grasp the concept of autocorrelation in an intuitive manner.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1797-1801"},"PeriodicalIF":2.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502870/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251036","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":"Thermal expansion of LaB₆ from 298 to 998 K.","authors":"E Koray Akdoğan, E Andrew Payzant","doi":"10.1107/S1600576725005898","DOIUrl":"10.1107/S1600576725005898","url":null,"abstract":"<p><p>We propose LaB₆ as a temperature calibration standard for high-temperature (HT) X-ray diffractometry owing to its high temperature stability. Such HT applications require a reliable HT lattice parameter or, equivalently, peak position data, which have not been readily accessible to the diffraction community to date. As such, the thermal expansion behavior of NIST SRM 660a LaB₆ was assessed in the temperature range 298-998 K using HT Bragg-Brentano parafocusing θ:θ X-ray diffractometry in conjunction with Rietveld analysis. Data were collected in the 2θ range 20-150° at a data collection rate of 0.5° θ min^-1 in air and at 1 atm. The temperature was stepped in 50 K increments. The cubic unit-cell lattice parameter [<i>a</i>(<i>T</i>)] of LaB₆ in Å was found to vary as <i>a</i>(<i>T</i>) = 4.15678 (±0.00001) + Ξ(<i>T</i> - 298 K) + Ψ(<i>T</i> - 298 K)², where Ξ = 2.4645 × 10^-5 (±4.8904 × 10^-8) Å K^-1 and Ψ = 1.0325 × 10^-8 (±6.7376 × 10^-11) Å K^-1. The isobaric volume thermal expansion coefficient (TEC) was obtained as α_V ^P  = (5.9291 × 10^-6) + (4.9680 × 10^-9)(<i>T</i> - 298 K) K^-1, from which the corresponding linear TEC was obtained as α_L ^P = (1.9764 × 10^-6) + (1.6560 × 10^-9)(<i>T</i> - 298 K) K^-1. The 3 × 3 matrix representations of the single-crystal isobaric linear TEC and the volume expansivity were obtained for the cubic crystal class to which LaB₆ belongs. Also, the temperature dependence of the lattice parameter data of this study was compared with past landmark studies on LaB₆ by Dutchak <i>et al.</i> [<i>Inorg. Mater.</i> (1972), <b>8</b>, 1877-1880] and Aivazov <i>et al.</i> [<i>Inorg. Mater.</i> (1979), <b>15</b>, 1015-1016].</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1635-1642"},"PeriodicalIF":2.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502857/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251194","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>SUNBIM 4.0</i> software: new developments in small- and wide-angle X-ray scattering data analysis for scanning mode and grazing-incidence geometry.","authors":"Francesco Scattarella, Davide Altamura, Teresa Sibillano, Liberato De Caro, Dritan Siliqi, Cinzia Giannini","doi":"10.1107/S1600576725005904","DOIUrl":"10.1107/S1600576725005904","url":null,"abstract":"<p><p><i>SUNBIM</i> (supramolecular and submolecular nano- and biomaterials X-ray imaging) is a computer suite of integrated programs which, through a user-friendly graphical interface, is able to perform a number of functions for (grazing-incidence) small- and wide-angle X-ray scattering [(GI)SAXS and (GI)WAXS] data analysis. The software combines in the same package both originally developed algorithms and reliable methods documented in the literature. Recently, new tools have been added to the original program that are particularly devoted to data reduction. The release presented in this work, named <i>SUNBIM 4.0</i>, features a new interface to perform deeper data reduction for multi-scan SAXS/WAXS, including dark-current subtraction, background evaluation and subtraction, and normalization of scattering intensity against local sample thickness derived from absorption contrast maps. In <i>SUNBIM 4.0</i>, these functionalities have been made accessible for data sets in .edf, a data format commonly used by many next-generation X-ray detectors, thanks to a new guided procedure for converting entire multi-scan data sets into a format readable by the software. A new functionality in the single data analysis section has been implemented, consisting of a semi-automatic background subtraction from the 1D profile of the azimuthal integration, corrected for a flat-panel detector geometry, to enhance peak visibility at large scattering angles (WAXS/GIWAXS). This new <i>SUNBIM</i> release will include a Microsoft Windows installer, as in the previous version, and will also be available for Mac OSX. We are confident that the new features will enable a more accurate and comprehensive analysis of (GI)SAXS/(GI)WAXS data, addressing the issues and limitations of the previous release while also enhancing the extraction of structural information contained within the data.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1817-1826"},"PeriodicalIF":2.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502861/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251212","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>XRDlicious</i>: an interactive web-based platform for online calculation of diffraction patterns and radial distribution functions from crystal structures.","authors":"Miroslav Lebeda, Jan Drahokoupil, Petr Veřtát, Šimon Svoboda, Vojtěch Smola, Ubaid Ahmed, Petr Vlčák","doi":"10.1107/S1600576725005370","DOIUrl":"10.1107/S1600576725005370","url":null,"abstract":"<p><p><i>XRDlicious</i> is an online computational tool for calculating powder X-ray diffraction and neutron diffraction patterns (diffractograms) and partial and total radial distribution functions [(P)RDFs] from crystal structures. It features a user-friendly browser-based interface that supports widely used structural file formats, such as CIF, POSCAR, XYZ and LMP. The structures can be either uploaded or retrieved directly from the Crystallography Open Database, Materials Project and Automatic FLOW databases via an integrated search interface. Uploaded structures can be modified and exported in CIF, POSCAR, LMP or XYZ formats. The tool also enables the conversion of experimental powder diffraction data between different wavelengths, to <i>d</i>-space or <i>q</i>-space representations, and between fixed or automatic divergence slits. By eliminating the need for software installation, this application ensures accessibility across various devices (including mobile phones and tablets) and different computer operating systems. Its ability to simultaneously plot diffraction patterns from multiple structures is particularly useful for comparing structures obtained from computational simulations. Beyond research applications, its intuitive interface also makes it suitable for educational purposes, allowing students to explore concepts such as diffraction patterns and (P)RDFs in an easily approachable way. <i>XRDlicious</i> is accessible at https://xrdlicious.com.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1810-1816"},"PeriodicalIF":2.8,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502867/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251198","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":"Solving disorder in (3D) real space: a comparative study of the three-dimensional difference pair distribution function and atomic resolution holography reconstructions.","authors":"Jens R Stellhorn, Arianna Minelli, Emily G Meekel, Ella M Schmidt","doi":"10.1107/S1600576725005977","DOIUrl":"10.1107/S1600576725005977","url":null,"abstract":"<p><p>The quantitative analysis of local ordering principles in disordered crystalline systems has gained much attention over the past few years, as it is often considered crucial for optimizing material functionality. This development has been driven by significant advancements in computational and experimental methods, which have led to the establishment and widespread use of various analytical techniques. In this study, we perform model calculations to compare the effectiveness of atomic resolution holography and three-dimensional difference pair distribution function analysis (3D-ΔPDF). Using Cu₃Au as a model system, we demonstrate an approach to derive local order parameters quantitatively and show that both techniques are well suited to quantifying chemical short-range order correlations and local bond-distance variations. By evaluating the strengths and limitations of both techniques, we advocate for their combined use to solve complex short-range order problems accurately.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 5","pages":"1605-1614"},"PeriodicalIF":2.8,"publicationDate":"2025-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12502872/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145251128","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":"Velocity gradient dependent structures of 12-2-12 wormlike micelles: insights from small-angle neutron scattering in the 1-2 shear plane.","authors":"Hiroki Iwase, Shin-Ichi Takata, Toshiaki Morikawa, Tomokazu Yoshimura","doi":"10.1107/S1600576725006521","DOIUrl":"10.1107/S1600576725006521","url":null,"abstract":"<p><p>The velocity gradient dependent shear-induced structural evolution of wormlike micelles (WLMs) formed by a gemini-type cationic surfactant (12-2-12) in an aqueous solution was investigated using small-angle neutron scattering (SANS). To achieve this, a cell for observation in the velocity-velocity gradient (1-2) shear plane was constructed. SANS measurements were conducted at multiple positions across the gap of this 1-2 shear cell under various shear rates, covering both shear-thickening and shear-thinning regimes. During shear thickening at apparent shear rates of 70-200 s^-1, a clear position-dependent alignment of WLMs was observed, with higher orientation near the rotor. In contrast, the intermicellar distance remained largely uniform across the gap. Neutron transmission measurements indicated no significant macroscopic concentration fluctuations. These results suggest that shear thickening is primarily driven by shear-induced micellar elongation and orientation, rather than the formation of concentration fluctuations. This study indicates the utility of SANS measurements in the 1-2 shear plane in revealing spatially resolved structural details, providing crucial insights into the 3D behavior of complex fluids under shear and complementing previous Rheo-SANS findings.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 4","pages":"1407-1416"},"PeriodicalIF":2.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12321015/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144789237","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":"Fundamental motifs and parity within the crystallographic point groups.","authors":"Maureen M Julian, Matthew Macauley","doi":"10.1107/S1600576725005631","DOIUrl":"10.1107/S1600576725005631","url":null,"abstract":"<p><p>This paper analyzes the Hasse diagram, or family tree, of the 3D crystal classes, also called geometric crystal classes. The 32 point-group classes are partitioned into seven crystal systems. In this paper, the structures of these systems are analyzed, leading to a new understanding of the relationships among and within them. The point groups, including their subgroups up to conjugacy, appear in six structural <i>motifs</i> in the Hasse diagram or family tree. Each motif has a <i>parity</i> - even or odd - that determines its structure. In three dimensions, the odd motifs are called monads, trigonals and cubics, and the even motifs are called dyads, tetragonals and hexagonals. Of the 32 classes of 3D point groups, 29 have a well defined parity, in that they appear in either an even or an odd motif. In contrast, the three monoclinic point groups are 'ambidextrous', in that they appear in two motifs, one of each parity. An analysis of the ten 2D point groups reveals an analogous structure, except for the presence of an ambidextrous crystal system. The striking structural uniformity of the motifs across the Hasse diagram confirms that they are essential building blocks of the crystallographic point groups.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 4","pages":"1447-1454"},"PeriodicalIF":2.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12321018/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144789230","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":"Oblique diffraction geometry for the observation of several non-coplanar Bragg reflections under identical illumination.","authors":"Carsten Detlefs, Axel Henningsson, Brinthan Kanesalingam, Adam A W Cretton, Cedric Corley-Wiciak, Felix T Frankus, Dayeeta Pal, Sara Irvine, Sina Borgi, Henning F Poulsen, Can Yildirim, Leora E Dresselhaus-Marais","doi":"10.1107/S1600576725005862","DOIUrl":"10.1107/S1600576725005862","url":null,"abstract":"<p><p>A method to determine the strain tensor and local lattice rotation with dark-field X-ray microscopy is presented. Using a set of at least three non-coplanar symmetry-equivalent Bragg reflections, the illuminated volume of the sample can be kept constant for all reflections, facilitating easy registration of the measured lattice variations. This requires an oblique diffraction geometry, <i>i.e.</i> the diffraction plane is neither horizontal nor vertical. We derive a closed analytical expression that allows determination of the strain and lattice rotation from the deviation of experimental observables (<i>e.g.</i> goniometer angles) from their nominal values for an unstrained lattice.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 4","pages":"1439-1446"},"PeriodicalIF":2.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12321021/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144789138","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":"High-energy diffuse X-ray scattering at ultra-small-angle grazing incidence for local structure study of single-crystalline thin films.","authors":"Joohee Bang, Nives Strkalj, Martin F Sarott, Yevheniia Kholina, Morgan Trassin, Thomas Weber","doi":"10.1107/S1600576725005837","DOIUrl":"10.1107/S1600576725005837","url":null,"abstract":"<p><p>We present a novel experimental approach employing high-energy X-ray scattering in ultra-small-angle grazing-incidence geometry to investigate local atomic structures in single-crystalline thin films. This non-destructive and non-invasive method overcomes the limitations of conventional moderate-energy grazing-incidence diffraction, achieving both high reciprocal-space resolution and coverage and high surface sensitivity. By leveraging high-energy X-ray diffraction, we enable quantitative analysis of local structures in the model system of ferroelectric PbTiO₃ and dielectric SrTiO₃ superlattices through three-dimensional difference pair distribution function analysis. The approach provides detailed insights into atomic structures in single-crystalline thin films with local order, capturing information on spatial correlations within and across unit cells.</p>","PeriodicalId":14950,"journal":{"name":"Journal of Applied Crystallography","volume":"58 Pt 4","pages":"1417-1427"},"PeriodicalIF":2.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12321022/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144789231","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}