12 results
Now showing1 - 10 of 12
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Fast and efficient hard X-ray projection imaging below 10 nm resolution(Optica Publishing Group, 2024-08-12); ; ; High-resolution X-ray imaging of noncrystalline objects is often achieved through the approach of scanning coherent diffractive imaging known as ptychography. The imaging resolution is usually limited by the scattering properties of the sample, where weak diffraction signals at the highest scattering angles compete with parasitic scattering. Here, we demonstrate that X-ray multilayer Laue lenses with a high numerical aperture (NA) can be used to create a strong reference beam that holographically boosts weak scattering from the sample over a large range of scattering angles, enabling high-resolution imaging that is tolerant of such background. An imaging resolution of sub-10 nm was achieved at a photon energy of 17.4 keV with lenses of 0.014 NA from a Siemens star test object and a sample of hierarchical nanoporous gold, recording projection holograms at an effective magnification of more than 30,000 directly on a pixel-array detector. A numerical study compared this approach to low-NA far-field ptychography, indicating significant advantages for using high-NA lenses in the presence of background noise. This imaging modality is particularly fast and efficient at recording high-resolution transmission phase-contrast images over large fields of view in a facile manner.Publicationtype: Journal Article14 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Method and a system for examining sample particles by X-ray radiation(2022-11-09); ; ; ; The invention relates to a method and a system (1) for examining sample particles (2) by X-ray radiation. The method comprises the following steps: a) Generating a flow of a sample fluid (4) along a fluid path (6) in a transport direction Y, wherein sample particles (2) are distributed in the sample fluid (4); b) Exposing the sample fluid (4) flowing through a first application section (8) of the fluid path (6) to a first laser light generated by a first laser light source (38) for a first holding time period such that a first optical light pressure is applied on sample particles (2) entering the first application section (8) resulting in a bunch (12) of sample particles (2), which is released at the end of the first holding time period; c) Repeating step b) such that the fluid flow of the sample fluid (4) leaving the first application section (8) carries a first sequence (14) of spaced bunches (12) of sample particles (2); d) Exposing the sample fluid (4) flowing through a detection section (16) of the fluid path (6) downstream to the first application section (8) to an X-ray set of at least one X-ray pulse generated by an X-ray source (18); e) Repeating step d) to form a second sequence of spaced X-ray sets such that each of the spaced X-ray sets partly or fully intersects a different bunch (12) of the bunches (12) of sample particles (2) carried by the sample fluid (4) flowing through the detection section (16); and f) Detecting by means of an X-ray detector (22) an X-ray radiation formed by the X-ray pulses of the second sequence of spaced X-ray set modified by the bunches (12,32) of sample particles (2) in step e).Publicationtype: Patent29 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optical bunching of particles in a liquid flow(2021-10-11); ; ; ; High-speed liquid micro-jets are used to rapidly and repeatedly deliver protein microcrystals to focused and pulsed X-ray beams in the method of serial femtosecond crystallography. However, the current continuous flow of crystals is mismatched to the arrival of X-ray pulses, wasting vast amounts of an often rare and precious sample. Here, we introduce a method to address this problem by periodically trapping and releasing crystals in the liquid flow, creating locally concentrated crystal bunches, using an optical trap integrated in the microfluidic supply line. We experimentally demonstrate a 30-fold increase of particle concentration into 10 Hz bunches of 6.4 µm diameter polystyrene particles. Furthermore, using particle trajectory simulations, a comprehensive description of the optical bunching process and parameter space is presented. Adding this compact optofluidics device to existing injection systems would thereby dramatically reduce sample consumption and extend the application of serial crystallography to a greater range of protein crystal systems that cannot be produced in high abundance. Our approach is suitable for other microfluidic systems that require synchronous measurements of flowing objects.Publicationtype: Journal Article64 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , On the use of multilayer Laue lenses with X-ray free electron lasers(SPIE, 2021); ; We report on the use of multilayer Laue lenses to focus the intense X-ray Free Electron Laser (XFEL) beam at the European XFEL to a spot size of a few tens of nanometers. We present the procedure to align and characterize these lenses and discuss challenges working with the pulse trains from this unique X-ray source.Publicationtype: Conference Paper18 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Segmented flow generator for serial crystallography at the European X-ray free electron laser(2020-09-09); ; ; ; Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported.Publicationtype: Journal ArticleScopus© Citations 28 279 184 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Time-resolved serial femtosecond crystallography at the European XFEL(2020-01-01); ; ; ; The European XFEL (EuXFEL) is a 3.4-km long X-ray source, which produces femtosecond, ultrabrilliant and spatially coherent X-ray pulses at megahertz (MHz) repetition rates. This X-ray source has been designed to enable the observation of ultrafast processes with near-atomic spatial resolution. Time-resolved crystallographic investigations on biological macromolecules belong to an important class of experiments that explore fundamental and functional structural displacements in these molecules. Due to the unusual MHz X-ray pulse structure at the EuXFEL, these experiments are challenging. Here, we demonstrate how a biological reaction can be followed on ultrafast timescales at the EuXFEL. We investigate the picosecond time range in the photocycle of photoactive yellow protein (PYP) with MHz X-ray pulse rates. We show that difference electron density maps of excellent quality can be obtained. The results connect the previously explored femtosecond PYP dynamics to timescales accessible at synchrotrons. This opens the door to a wide range of time-resolved studies at the EuXFEL.Publicationtype: Journal Article190 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Evaluation of serial crystallographic structure determination within megahertz pulse trains(American Institute of Physics (AIP), 2019-12-04); ; ; ; The new European X-ray Free-Electron Laser (European XFEL) is the first X-ray free-electron laser capable of delivering intense X-ray pulses with a megahertz interpulse spacing in a wavelength range suitable for atomic resolution structure determination. An outstanding but crucial question is whether the use of a pulse repetition rate nearly four orders of magnitude higher than previously possible results in unwanted structural changes due to either radiation damage or systematic effects on data quality. Here, separate structures from the first and subsequent pulses in the European XFEL pulse train were determined, showing that there is essentially no difference between structures determined from different pulses under currently available operating conditions at the European XFEL.Publicationtype: Journal ArticleScopus© Citations 27 152 194 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Membrane protein megahertz crystallography at the European XFEL(Nature Publishing Group, 2019-11-04); ; ; ; The world’s first superconducting megahertz repetition rate hard X-ray free-electron laser (XFEL), the European XFEL, began operation in 2017, featuring a unique pulse train structure with 886 ns between pulses. With its rapid pulse rate, the European XFEL may alleviate some of the increasing demand for XFEL beamtime, particularly for membrane protein serial femtosecond crystallography (SFX), leveraging orders-of-magnitude faster data collection. Here, we report the first membrane protein megahertz SFX experiment, where we determined a 2.9 Å-resolution SFX structure of the large membrane protein complex, Photosystem I, a > 1 MDa complex containing 36 protein subunits and 381 cofactors. We address challenges to megahertz SFX for membrane protein complexes, including growth of large quantities of crystals and the large molecular and unit cell size that influence data collection and analysis. The results imply that megahertz crystallography could have an important impact on structure determination of large protein complexes with XFELs.Publicationtype: Journal ArticleScopus© Citations 43 518 242 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , 3D printed nozzles on a silicon fluidic chip(American Institute of Physics (AIP), 2019-03-20); ; ; ; Serial femtosecond crystallography is a new method for protein structure determination utilizing intense and destructive X-ray pulses generated by free-electron lasers. The approach requires the means to deliver hydrated protein crystals to a focused X-ray beam and replenish them at the repetition rate of the pulses. A liquid-jet sample delivery system where a gas dynamic virtual nozzle is printed directly on a silicon-glass microfluidic chip using a 2-photon-polymerization 3D printing process is implemented. This allows for rapid prototyping and high-precision production of nozzles to suit the characteristics of a particular sample and opens up the possibility for high-throughput and versatile sample delivery systems that can integrate microfluidic components for sample detection, characterisation, or control. With the hybrid system described here, stable liquid jets with diameters between 1.5 µm at liquid flow rate of 1.5 µl/min and more than 20 µm at liquid flow rate of 100 µl/min under atmospheric and vacuum conditions are generated. The combination of 2D lithography with direct 3D printing may streamline the integration of free-form-features and also facilitate scale-up production of such integrated microfluidic devices that may be useful in many other applications such as flow cytometry and optofluidics.Publicationtype: Journal ArticleScopus© Citations 15 424 517 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Hochdruckstabile direkte Anbindung 3D gedruckter Mikrodüsen auf einen Silizium-Glas-Fluidik-ChipPublicationtype: Conference Paper97