Taisen Zuo, Zhangjiang Lu, Hong Zhu, Zehua Han, Changdong Deng, Yongcheng He, Long Tian, Tianhao Wang, Songwen Xiao, Zhengqiang He, Xiong Lin, Changli Ma, He Cheng
{"title":"Compact sextupole permanent magnet lens: a practical approach to focusing pulsed neutrons","authors":"Taisen Zuo, Zhangjiang Lu, Hong Zhu, Zehua Han, Changdong Deng, Yongcheng He, Long Tian, Tianhao Wang, Songwen Xiao, Zhengqiang He, Xiong Lin, Changli Ma, He Cheng","doi":"10.1107/S1600576725007496","DOIUrl":"https://doi.org/10.1107/S1600576725007496","url":null,"abstract":"<p>The focusing of pulsed neutrons can increase neutron current, reduce sample volume and enable access to smaller scattering angles. Consequently, it represents a critical challenge for next-generation spallation neutron sources. The primary difficulty stems from the inherent chromatic aberration of white neutrons. Here, a new compact nested rotating sextupole permanent magnet (Nest-Rotating-SPM) lens, with a total length of 200 mm, was developed and tested on the very small angle neutron scattering instrument at the China Spallation Neutron Source. Through synchronization of the outer sextupole lens rotation with the neutron pulse from the source, we achieved aberration-free focusing of neutrons with wavelengths between 11.0 and 15.5 Å for the first time. The implementation of water cooling and carbon fibre winding ensures both magnetic field stability and mechanical robustness of the inner sextupole. The compact design incorporating bridge sextupoles enables modular assembly of multiple lens units for focusing pulsed neutrons with wavelengths shorter than 10.0 Å, making it practically useful in a pulsed neutron instrument to enhance neutron current or access lower scattering vectors. Additional research is required to mitigate background noise.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 5","pages":"1595-1604"},"PeriodicalIF":2.8,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237336","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}
Michela La Bella, Marilyn Sarkis, Christian Geindreau, Fabrice Emeriault, Haixing Fang, Jonathan P. Wright, Catherine Noiriel, Antoine Naillon
{"title":"Insights on the textural and crystallographic properties of calcite obtained through MICP using advanced synchrotron diffraction imaging","authors":"Michela La Bella, Marilyn Sarkis, Christian Geindreau, Fabrice Emeriault, Haixing Fang, Jonathan P. Wright, Catherine Noiriel, Antoine Naillon","doi":"10.1107/S1600576725007010","DOIUrl":"https://doi.org/10.1107/S1600576725007010","url":null,"abstract":"<p>The microbially induced calcite precipitation (MICP) technique is used to turn sand into a cohesive medium by inducing the precipitation of calcite crystals in the pores. This work presents, for the first time, a comprehensive study of the morphological and crystallographic properties of bio-induced calcite using scanning 3D X-ray diffraction and phase contrast tomography, highlighting possible implications of the calcite precipitation process on the microstructure of biocemented sand. The combined approach of diffraction and imaging techniques with laboratory characterization tools revealed the link between morphology and crystallinity of bio-induced calcite crystals and the preferred orientation of crystals at the surface of sand grains. These results provide useful insights not only into the role of the crystallographic properties of calcite in determining the microstructure of biocemented sand but also on the influence of <i>Sporosarcina Pasteurii</i> on the precipitation process. The potential of scanning 3D X-ray diffraction in tackling challenges related to construction and geomaterials is demonstrated.</p>","PeriodicalId":48737,"journal":{"name":"Journal of Applied Crystallography","volume":"58 5","pages":"1728-1741"},"PeriodicalIF":2.8,"publicationDate":"2025-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237119","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}
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