Lohse, Leon Merten

[["dc.bibliographiccitation.firstpage","9842"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Optics Express"],["dc.bibliographiccitation.lastpage","9859"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Lohse, L. M."],["dc.contributor.author","Vassholz, M."],["dc.contributor.author","Töpperwien, M."],["dc.contributor.author","Jentschke, T."],["dc.contributor.author","Bergamaschi, A."],["dc.contributor.author","Chiriotti, S."],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2020-12-10T18:42:02Z"],["dc.date.available","2020-12-10T18:42:02Z"],["dc.date.issued","2020"],["dc.description.abstract","A main challenge in x-ray µCT with laboratory radiation derives from the broad spectral content, which in contrast to monochromatic synchrotron radiation gives rise to reconstruction artifacts and impedes quantitative reconstruction. Due to the low spectral brightness of these sources, monochromatization is unfavorable and parallel recording of a broad bandpath is practically indispensable. While conventional CT sums up all spectral components into a single detector value, spectral CT discriminates the data in several spectral bins. Here we show that a new generation of charge integrating and interpolating pixel detectors is ideally suited to implement spectral CT with a resolution in the range of 10 µm. We find that the information contained in several photon energy bins largely facilitates automated classification of materials, as demonstrated for of a mouse cochlea. Bones, soft tissues, background and metal implant materials are discriminated automatically. Importantly, this includes taking a better account of phase contrast effects, based on tailoring reconstruction parameters to specific energy bins."],["dc.identifier.doi","10.1364/OE.385389"],["dc.identifier.eissn","1094-4087"],["dc.identifier.pmid","32225584"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/17771"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/77783"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.issn","1094-4087"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","Goescholar"],["dc.rights.uri","https://goedoc.uni-goettingen.de/licenses"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","biomedical tomography"],["dc.title","Spectral µCT with an energy resolving and interpolating pixel detector"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","852"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Journal of Synchrotron Radiation"],["dc.bibliographiccitation.lastpage","859"],["dc.bibliographiccitation.volume","27"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Robisch, Anna Lena"],["dc.contributor.author","Töpperwien, Mareike"],["dc.contributor.author","Maretzke, Simon"],["dc.contributor.author","Krenkel, Martin"],["dc.contributor.author","Hagemann, Johannes"],["dc.contributor.author","Salditt, Tim"],["dc.date.accessioned","2020-12-10T18:25:59Z"],["dc.date.available","2020-12-10T18:25:59Z"],["dc.date.issued","2020"],["dc.description.abstract","Propagation-based phase-contrast X-ray imaging is by now a well established imaging technique, which – as a full-field technique – is particularly useful for tomography applications. Since it can be implemented with synchrotron radiation and at laboratory micro-focus sources, it covers a wide range of applications. A limiting factor in its development has been the phase-retrieval step, which was often performed using methods with a limited regime of applicability, typically based on linearization. In this work, a much larger set of algorithms, which covers a wide range of cases (experimental parameters, objects and constraints), is compiled into a single toolbox – the HoloTomoToolbox – which is made publicly available. Importantly, the unified structure of the implemented phase-retrieval functions facilitates their use and performance test on different experimental data."],["dc.identifier.doi","10.1107/S1600577520002398"],["dc.identifier.eissn","1600-5775"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75904"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.issn","1600-5775"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 4.0"],["dc.subject.gro","x-ray imaging"],["dc.subject.gro","biomedical tomography"],["dc.title","A phase-retrieval toolbox for X-ray holography and tomography"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2494"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","ChemCatChem"],["dc.bibliographiccitation.lastpage","2507"],["dc.bibliographiccitation.volume","13"],["dc.contributor.author","Veselý, Martin"],["dc.contributor.author","Valadian, Roozbeh"],["dc.contributor.author","Lohse, Leon Merten"],["dc.contributor.author","Töpperwien, Mareike"],["dc.contributor.author","Spiers, Kathryn"],["dc.contributor.author","Garrevoet, Jan"],["dc.contributor.author","Vogt, Eelco T. C."],["dc.contributor.author","Salditt, Tim"],["dc.contributor.author","Weckhuysen, Bert M."],["dc.contributor.author","Meirer, Florian"],["dc.date.accessioned","2021-08-22T15:31:06Z"],["dc.date.available","2021-08-22T15:31:06Z"],["dc.date.issued","2021-03-31"],["dc.description.abstract","Catalyst deactivation involves a complex interplay of processes taking place at different length and time scales. Understanding this phenomenon is one of the grand challenges in solid catalyst characterization. A process contributing to deactivation is carbon deposition (i. e., coking), which reduces catalyst activity by limiting diffusion and blocking active sites. However, characterizing coke formation and its effects remains challenging as it involves both the organic and inorganic phase of the catalytic process and length scales from the atomic scale to the scale of the catalyst body. Here we present a combination of hard X-ray imaging techniques able to visualize in 3-D the distribution, effect and nature of carbon deposits in the macro-pore space of an entire industrially used catalyst particle. Our findings provide direct evidence for coke promoting effects of metal poisons, pore clogging by coke, and a correlation between carbon nature and its location. These results provide a better understanding of the coking process, its relation to catalyst deactivation and new insights into the efficiency of the industrial scale process of fluid catalytic cracking."],["dc.identifier.doi","10.1002/cctc.202100276"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/88786"],["dc.language.iso","en"],["dc.relation.orgunit","Institut für Röntgenphysik"],["dc.relation.workinggroup","RG Salditt (Structure of Biomolecular Assemblies and X-Ray Physics)"],["dc.rights","CC BY 4.0"],["dc.subject.gro","x-ray imaging"],["dc.title","3‐D X‐ray Nanotomography Reveals Different Carbon Deposition Mechanisms in a Single Catalyst Particle"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","original_ja"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]