SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "L773:1600 5775 "

Sökning: L773:1600 5775

  • Resultat 1-50 av 101
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Agåker, Marcus, et al. (författare)
  • A five-axis parallel kinematic mirror unit for soft X-ray beamlines at MAX IV
  • 2020
  • Ingår i: Journal of Synchrotron Radiation. - : INT UNION CRYSTALLOGRAPHY. - 0909-0495 .- 1600-5775. ; 27, s. 262-271
  • Tidskriftsartikel (refereegranskat)abstract
    • With the introduction of the multi-bend achromats in the new fourth-generation storage rings the emittance has decreased by an order of magnitude resulting in increased brightness. However, the higher brightness comes with smaller beam sizes and narrower radiation cones. As a consequence, the requirements on mechanical stability regarding the beamline components increases. Here an innovative five-axis parallel kinematic mirror unit for use with soft X-ray beamlines using off-axis grazing-incidence optics is presented. Using simulations and measurements from the HIPPIE beamline at the MAX IV Laboratory it is shown that it has no Eigen frequencies below 90 Hz. Its positioning accuracy is better than 25 nm linearly and 17-35 mu rad angularly depending on the mirror chamber dimensions.
  •  
2.
  • Agåker, Marcus, et al. (författare)
  • An ultra-high-stability four-axis ultra-high-vacuum sample manipulator
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - : International Union Of Crystallography. - 1600-5775 .- 0909-0495. ; 28:Pt 4, s. 1059-1068
  • Tidskriftsartikel (refereegranskat)abstract
    • A report on a four-axis ultra-high-stability manipulator developed for use at the Veritas and Species RIXS beamlines at MAX IV Laboratory, Lund, Sweden, is presented. The manipulator consists of a compact, light-weight X-Y table with a stiffened Z tower carrying a platform with a rotary seal to which a manipulator rod holding the sample can be attached. Its design parameters have been optimized to achieve high eigen-frequencies via a light-weight yet stiff construction, to absorb forces without deformations, provide a low center of gravity, and have a compact footprint without compromising access to the manipulator rod. The manipulator system can house a multitude of different, easily exchangeable, manipulator rods that can be tailor-made for specific experimental requirements without having to rebuild the entire sample positioning system. It is shown that the manipulator has its lowest eigen-frequency at 48.5 Hz and that long-term stability is in the few tens of nanometres. Position accuracy is shown to be better than 100 nm. Angular accuracy is in the 500 nrad range with a long-term stability of a few hundred nanoradians.
  •  
3.
  • Al Dmour, Eshraq, et al. (författare)
  • Diffraction-limited storage-ring vacuum technology.
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21:Pt 5, s. 878-883
  • Tidskriftsartikel (refereegranskat)abstract
    • Some of the characteristics of recent ultralow-emittance storage-ring designs and possibly future diffraction-limited storage rings are a compact lattice combined with small magnet apertures. Such requirements present a challenge for the design and performance of the vacuum system. The vacuum system should provide the required vacuum pressure for machine operation and be able to handle the heat load from synchrotron radiation. Small magnet apertures result in the conductance of the chamber being low, and lumped pumps are ineffective. One way to provide the required vacuum level is by distributed pumping, which can be realised by the use of a non-evaporable getter (NEG) coating of the chamber walls. It may not be possible to use crotch absorbers to absorb the heat from the synchrotron radiation because an antechamber is difficult to realise with such a compact lattice. To solve this, the chamber walls can work as distributed absorbers if they are made of a material with good thermal conductivity, and distributed cooling is used at the location where the synchrotron radiation hits the wall. The vacuum system of the 3 GeV storage ring of MAX IV is used as an example of possible solutions for vacuum technologies for diffraction-limited storage rings.
  •  
4.
  • Allahgholi, Aschkan, et al. (författare)
  • The Adaptive Gain Integrating Pixel Detector at the European XFEL
  • 2019
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 26, s. 74-82
  • Tidskriftsartikel (refereegranskat)abstract
    • The Adaptive Gain Integrating Pixel Detector (AGIPD) is an X-ray imager, custom designed for the European X-ray Free-Electron Laser (XFEL). It is a fast, low-noise integrating detector, with an adaptive gain amplifier per pixel. This has an equivalent noise of less than 1keV when detecting single photons and, when switched into another gain state, a dynamic range of more than 10(4)photons of 12keV. In burst mode the system is able to store 352 images while running at up to 6.5MHz, which is compatible with the 4.5MHz frame rate at the European XFEL. The AGIPD system was installed and commissioned in August 2017, and successfully used for the first experiments at the Single Particles, Clusters and Biomolecules (SPB) experimental station at the European XFEL since September 2017. This paper describes the principal components and performance parameters of the system.
  •  
5.
  • Almkvist, Gunnar, et al. (författare)
  • K-edge XANES analysis of sulfur compounds: an investigation of the relative intensities using internal calibration
  • 2010
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 17, s. 683-688
  • Tidskriftsartikel (refereegranskat)abstract
    • Sulfur K-edge XANES (X-ray absorption near-edge structure) spectroscopy is an excellent tool for determining the speciation of sulfur compounds in complex matrices. This paper presents a method to quantitatively determine the kinds of sulfur species in natural samples using internally calibrated reference spectra of model compounds Owing to significant self-absorption of formed fluorescence radiation in the sample itself the fluorescence signal displays a non-linear correlation with the sulfur content over a wide concentration range. Self-absorption is also a problem at low total absorption of the sample when the sulfur compounds are present as particles. The post-edge Intensity patterns of the sulfur K-edge XANES spectra vary with the type of sulfur compound, with reducing sulfur compounds often having a higher post-edge intensity than the oxidized forms. In dilute solutions (less than 0.3-0.5%) it is possible to use sulfur K-edge XANES reference data for quantitative analysis of the contribution from different species The results show that it is essential to use an internal calibration system when performing quantitative XANES analysis Preparation of unknown samples must take both the total absorption and possible presence of self-absorbing particles into consideration.
  •  
6.
  • Anderson, Danielle L., et al. (författare)
  • Spatial and temporal distribution of gamma H2AX fluorescence in human cell cultures following synchrotron-generated X-ray microbeams : lack of correlation between persistent gamma H2AX foci and apoptosis
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 21, s. 801-810
  • Tidskriftsartikel (refereegranskat)abstract
    • Formation of gamma H2AX foci (a marker of DNA double-strand breaks), rates of foci clearance and apoptosis were investigated in cultured normal human fibroblasts and p53 wild-type malignant glioma cells after exposure to high-dose synchrotron-generated microbeams. Doses up to 283 Gy were delivered using beam geometries that included a microbeam array (50 mu m wide, 400 mu m spacing), single microbeams (60-570 mu m wide) and a broad beam (32 mm wide). The two cell types exhibited similar trends with respect to the initial formation and time-dependent clearance of gamma H2AX foci after irradiation. High levels of gamma H2AX foci persisted as late as 72 h post-irradiation in the majority of cells within cultures of both cell types. Levels of persistent foci after irradiation via the 570 mu m microbeam or broad beam were higher when compared with those observed after exposure to the 60 mu m microbeam or microbeam array. Despite persistence of gamma H2AX foci, these irradiation conditions triggered apoptosis in only a small proportion (<5%) of cells within cultures of both cell types. These results contribute to the understanding of the fundamental biological consequences of high-dose microbeam irradiations, and implicate the importance of non-apoptotic responses such as p53-mediated growth arrest (premature senescence).
  •  
7.
  • Artemiev, N, et al. (författare)
  • Ray-tracing analysis of diffractive-refractive X-ray optics
  • 2004
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 11, s. 157-162
  • Tidskriftsartikel (refereegranskat)abstract
    • Ray-tracing simulations of mistuned sagittal diffractive - refractive X-ray lenses (DRXL) are presented. In this article, firstly the characteristic aberrations for various types of crystal misalignments within one-crystal and four-crystal DRXLs are considered, and the sensitivity of such an optical system to the mutual misalignment of its components is discussed. The simulations reveal that a DRXL is not too sensitive to the adjustment of its components. In the second part of this article the performance of such lenses with ideal and approximate profiles is examined. Comparative analysis of parabolic and cylindrical DRXLs showed that, in the case when the linear source size is comparable with the acceptance of the lens, the performances of parabolic and cylindrical DRXLs are practically the same.
  •  
8.
  • Bergmann, U, et al. (författare)
  • High-resolution X-ray spectroscopy of rare events : a different look at local structure and chemistry
  • 2001
  • Ingår i: Journal of Synchrotron Radiation. - Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Appl Sci, Davis, CA 95616 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. : MUNKSGAARD INT PUBL LTD. - 0909-0495 .- 1600-5775. ; 8, s. 199-203
  • Tidskriftsartikel (refereegranskat)abstract
    • The combination of large-acceptance high-resolution X-ray optics with bright synchrotron sources permits quantitative analysis of rare events such as X-ray fluorescence from very dilute systems, weak fluorescence transitions or X-ray Raman scattering. Transition-metal K beta fluorescence contains information about spin and oxidation state; examples of the characterization of the Mn oxidation states in the oxygen-evolving complex of photosystem II and Mn-consuming spores from the marine bacillus SG-1 are presented. Weaker features of the K beta spectrum resulting from valence-level and 'interatomic' ligand to metal transitions contain detailed information on the ligand-atom type, distance and orientation. Applications of this spectral region to characterize the local structure of model compounds are presented. X-ray Raman scattering (XRS) is an extremely rare event, but also represents a unique technique to obtain bulk-sensitive low-energy (<600 eV) X-ray absorption fine structure (XAFS) spectra using hard ( 10 keV) X-rays. A photon is inelastically scattered, losing part of its energy to promote an electron into an unoccupied level. In many cases, the cross section is proportional to that of the corresponding absorption process yielding the same X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) features. XRS finds application for systems that defy XAFS analysis at low energies, e.g. liquids or highly concentrated complex systems, reactive compounds and samples under extreme conditions (pressure, temperature). Recent results are discussed.
  •  
9.
  • Bikondoa, Oier, et al. (författare)
  • On Compton scattering as a source of background in coherent diffraction imaging experiments
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 28, s. 538-549
  • Tidskriftsartikel (refereegranskat)abstract
    • Compton scattering is generally neglected in diffraction experiments because the incoherent radiation it generates does not give rise to interference effects and therefore is negligible at Bragg peaks. However, as the scattering volume is reduced, the difference between the Rayleigh (coherent) and Compton (incoherent) contributions at Bragg peaks diminishes and the incoherent part may become substantial. The consequences can be significant for coherent diffraction imaging at high scattering angles: the incoherent radiation produces background that smears out the secondary interference fringes, affecting thus the achievable resolution of the technique. Here, a criterion that relates the object shape and the resolution is introduced. The Compton contribution for several object shapes is quantified, and it is shown that the maximum achievable resolution along different directions has a strong dependence on the crystal shape and size.
  •  
10.
  • Birnsteinova, Sarlota, et al. (författare)
  • Online dynamic flat-field correction for MHz microscopy data at European XFEL
  • 2023
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 30:6, s. 1030-1037
  • Tidskriftsartikel (refereegranskat)abstract
    • The high pulse intensity and repetition rate of the European X-ray Free-Electron Laser (EuXFEL) provide superior temporal resolution compared with other X-ray sources. In combination with MHz X-ray microscopy techniques, it offers a unique opportunity to achieve superior contrast and spatial resolution in applications demanding high temporal resolution. In both live visualization and offline data analysis for microscopy experiments, baseline normalization is essential for further processing steps such as phase retrieval and modal decomposition. In addition, access to normalized projections during data acquisition can play an important role in decision-making and improve the quality of the data. However, the stochastic nature of X-ray free-electron laser sources hinders the use of standard flat-field normalization methods during MHz X-ray microscopy experiments. Here, an online (i.e. near real-time) dynamic flat-field correction method based on principal component analysis of dynamically evolving flat-field images is presented. The method is used for the normalization of individual X-ray projections and has been implemented as a near real-time analysis tool at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument of EuXFEL.
  •  
11.
  • Björling, Alexander, et al. (författare)
  • Contrast - a lightweight Python framework for beamline orchestration and data acquisition
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 28:4, s. 1253-1260
  • Tidskriftsartikel (refereegranskat)abstract
    • The emergence of fourth-generation synchrotrons is prompting the development of new systems for experimental control and data acquisition. However, as general control systems are designed to cover a wide set of instruments and techniques, they tend to become large and complicated, at the cost of experimental flexibility. Here we present Contrast, a simple Python framework for interacting with beamline components, orchestrating experiments and managing data acquisition. The system is presented and demonstrated via its application at the NanoMAX beamline of the MAX IV Laboratory.
  •  
12.
  • Blomberg, Sara, et al. (författare)
  • Combining synchrotron light with laser technology in catalysis research
  • 2018
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775 .- 0909-0495. ; 25:5, s. 1389-1394
  • Tidskriftsartikel (refereegranskat)abstract
    • High-energy surface X-ray diffraction (HESXRD) provides surface structural information with high temporal resolution, facilitating the understanding of the surface dynamics and structure of the active phase of catalytic surfaces. The surface structure detected during the reaction is sensitive to the composition of the gas phase close to the catalyst surface, and the catalytic activity of the sample itself may affect the surface structure, which in turn may complicate the assignment of the active phase. For this reason, planar laser-induced fluorescence (PLIF) and HESXRD have been combined during the oxidation of CO over a Pd(100) crystal. PLIF complements the structural studies with an instantaneous two-dimensional image of the CO2 gas phase in the vicinity of the active model catalyst. Here the combined HESXRD and PLIF operandomeasurements of CO oxidation over Pd(100) are presented, allowing for an improved assignment of the correlation between sample structure and the CO2distribution above the sample surface with sub-second time resolution.
  •  
13.
  • Bora, D. K., et al. (författare)
  • Influence of crystal structure, ligand environment and morphology on Co L-edge XAS spectral characteristics in cobalt compounds
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 22, s. 1450-1458
  • Tidskriftsartikel (refereegranskat)abstract
    • The electronic structure of a material plays an important role in its functionality for different applications which can be probed using synchrotron-based spectroscopy techniques. Here, various cobalt-based compounds, differing in crystal structure, ligands surrounding the central metal ion and morphology, have been studied by soft X-ray absorption spectroscopy (XAS) at the Co L-edge in order to measure the effect of these parameters on the electronic structure. A careful qualitative analysis of the spectral branching ratio and relative intensities of the L 3 and L 2 peaks provide useful insight into the electronic properties of compounds such as CoO/Co(OH)2, CoCl2.6H2O/CoF2.4H2O, CoCl2/CoF2, Co3O4 (bulk/nano/micro). For further detailed analysis of the XAS spectra, quantitative analysis has been performed by fitting the spectral profile with simulated spectra for a number of cobalt compounds using crystal field atomic multiplet calculations.
  •  
14.
  • Bouchet, Audrey, et al. (författare)
  • Chalcone JAI-51 improves efficacy of synchrotron microbeam radiation therapy of brain tumors
  • 2012
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 19, s. 478-482
  • Tidskriftsartikel (refereegranskat)abstract
    • Microbeam radiation therapy (MRT), a preclinical form of radiosurgery, uses spatially fractionated micrometre-wide synchrotron-generated X-ray beams. As MRT alone is predominantly palliative for animal tumors, the effects of the combination of MRT and a newly synthesized chemotherapeutic agent JAI-51 on 9L gliosarcomas have been evaluated. Fourteen days (D14) after implantation (D0), intracerebral 9LGS-bearing rats received either MRT, JAI-51 or both treatments. JAI-51, alone or immediately after MRT, was administered three times per week. Animals were kept up to similar to 20 weeks after irradiation or sacrificed at D16 or D28 after treatment for cell cycle analysis. MRT plus JAI-51 increased significantly the lifespan compared with MRT alone (p = 0.0367). JAI-51 treatment alone had no effect on rat survival. MRT alone or associated with JAI-51 induced a cell cycle blockade in G2/M (p < 0.01) while the combined treatment also reduced the proportion of G0/G1 cells. At D28 after irradiation, MRT and MRT/JAI-51 had a smaller cell blockade effect in the G2/M phase owing to a significant increase in tumor cell death rate (<2c) and a proportional increase of endoreplicative cells (>8c). The combination of MRT and JAI-51 increases the survival of 9LGS-bearing rats by inducing endoreduplication of DNA and tumor cell death; further, it slowed the onset of tumor growth resumption two weeks after treatment.
  •  
15.
  • Butorin, Sergei, et al. (författare)
  • X-ray spectroscopic study of chemical state in uranium carbides
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 29, s. 295-302
  • Tidskriftsartikel (refereegranskat)abstract
    • UC and UMeC2 (Me = Fe, Zr, Mo) carbides were studied by the high-energyresolution fluorescence-detected X-ray absorption (HERFD-XAS) technique at the U M-4 and L-3 edges. Both U M-4 and L-3 HERFD-XAS reveal some differences between UMeC2 and UC; there are differences also between the M-4 and L-3 edge results for both types of carbide in terms of the spectral width and energy position. The observed differences are attributed to the consequences of the U 5f, 6d-4d(3d) hybridization in UMeC2. Calculations of the U M-4 HERFD-XAS spectra were also performed using the Anderson impurity model (AIM). Based on the analysis of the data, the 5f occupancy in the ground state of UC was estimated to be 3.05 electrons. This finding is also supported by the analysis of U N-4,N-5 XAS of UC and by the results of the AIM calculations of the U 4f X-ray photoelectron spectrum of UC.
  •  
16.
  • Carbone, Dina, et al. (författare)
  • Design and performance of a dedicated coherent X-ray scanning diffraction instrument at beamline NanoMAX of MAX IV
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 29, s. 876-887
  • Tidskriftsartikel (refereegranskat)abstract
    • The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick-Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm. The endstation, in continued development, has been in user operation since summer 2017.
  •  
17.
  • Carlson, Stefan, et al. (författare)
  • XAFS experiments at beamline I811, MAX-lab synchrotron source, Sweden
  • 2006
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 13, s. 359-364
  • Tidskriftsartikel (refereegranskat)abstract
    • A description of a new facility for X-ray absorption spectroscopy at the materials science beamline, I811, at MAX-lab synchrotron source, Lund, Sweden, is given. The beamline is based on a superconducting multipole wiggler source inserted in a straight section of the 1.5 GeV MAX-II ring. X-rays in the energy range 2.4- 12 keV are extracted by a standard optical scheme consisting of a vertical collimating first mirror, double-crystal monochromator, and a second vertically focusing mirror. The second monochromator crystal provides sagittal focusing. The total flux impinging on the sample at 9 keV is 5 x 10(11) photons s(-1), for a minimum beam spot of 0.5 mm x 0.5 mm. The beamline has facilities for experiments in transmission, fluorescence and total-electronyield mode and experiments have been performed by international research groups on a wide range of materials, such as dilute systems with metal concentrations below 10 p. p. m.
  •  
18.
  • Cederström, Björn, et al. (författare)
  • Generalized prism-array lenses for hard X-rays
  • 2005
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 12, s. 340-344
  • Tidskriftsartikel (refereegranskat)abstract
    • A Fresnel-like X-ray lens can be constructed by a triangular array of identical prisms whose base corresponds to the 2 pi-shift length. Each column of prisms is progressively shifted from the optical axis by an arbitrary fraction of the prism height. Similarly to the multi-prism lens, quasi-parabolic profiles are formed by a superposition of straight-line segments. The resulting projected lens profile is approximately linear with a Fresnel-lens pattern superimposed on it to provide the focusing. This geometry exhibits a significantly larger effective aperture than conventional parabolic refractive lenses. Prototype lenses were fabricated by deep reactive ion etching of silicon. These one-dimensionally focusing lenses were tested at a synchrotron beamline and provided focal line-widths down to 1.4 mu m FWHM and an intensity gain of 39 at a photon energy of 13.4 keV. Fabrication imperfections gave rise to unwanted interference effects resulting in several intensity maxima in the focal plane. The presented design allows the focal length to be shortened without decreasing the feature size of the lens. Furthermore, this feature size does not limit the resolution as for real Fresnel optics.
  •  
19.
  • Chatterjee, Ruchira, et al. (författare)
  • XANES and EXAFS of dilute solutions of transition metals at XFELs
  • 2019
  • Ingår i: Journal of Synchrotron Radiation. - : INT UNION CRYSTALLOGRAPHY. - 0909-0495 .- 1600-5775. ; 26, s. 1716-1724
  • Tidskriftsartikel (refereegranskat)abstract
    • This work has demonstrated that X-ray absorption spectroscopy (XAS), both Mn XANES and EXAFS, of solutions with millimolar concentrations of metal is possible using the femtosecond X-ray pulses from XFELs. Mn XAS data were collected using two different sample delivery methods, a Rayleigh jet and a drop-on-demand setup, with varying concentrations of Mn. Here, a new method for normalization of XAS spectra based on solvent scattering that is compatible with data collection from a highly variable pulsed source is described. The measured XANES and EXAFS spectra of such dilute solution samples are in good agreement with data collected at synchrotron sources using traditional scanning protocols. The procedures described here will enable XFEL-based XAS on dilute biological samples, especially metalloproteins, with low sample consumption. Details of the experimental setup and data analysis methods used in this XANES and EXAFS study are presented. This method will also benefit XAS performed at high-repetition-rate XFELs such as the European XFEL, LCLS-II and LCLS-II-HE.
  •  
20.
  • Correa, J., et al. (författare)
  • The PERCIVAL detector : first user experiments
  • 2023
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 30, s. 242-250
  • Tidskriftsartikel (refereegranskat)abstract
    • The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.
  •  
21.
  • De Angelis, D., et al. (författare)
  • A sub-100 nm thickness flat jet for extreme ultraviolet to soft X-ray absorption spectroscopy
  • 2024
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 31:3 Pt, s. 605-612
  • Tidskriftsartikel (refereegranskat)abstract
    • Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown. 
  •  
22.
  • Dong, Weiwei, et al. (författare)
  • Fe0.79Si0.07B0.14 metallic glass gaskets for high-pressure research beyond 1 Mbar
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - : Wiley-Blackwell Publishing Ltd. - 0909-0495 .- 1600-5775. ; 29, s. 1167-1179
  • Tidskriftsartikel (refereegranskat)abstract
    • A gasket is an important constituent of a diamond anvil cell (DAC) assembly, responsible for the sample chamber stability at extreme conditions for X-ray diffraction studies. In this work, we studied the performance of gaskets made of metallic glass Fe0.79Si0.07B0.14 in a number of high-pressure X-ray diffraction (XRD) experiments in DACs equipped with conventional and toroidal-shape diamond anvils. The experiments were conducted in either axial or radial geometry with X-ray beams of micrometre to sub-micrometre size. We report that Fe0.79Si0.07B0.14 metallic glass gaskets offer a stable sample environment under compression exceeding 1 Mbar in all XRD experiments described here, even in those involving small-molecule gases (e.g. Ne, H-2) used as pressure-transmitting media or in those with laser heating in a DAC. Our results emphasize the materials importance for a great number of delicate experiments conducted under extreme conditions. They indicate that the application of Fe0.79Si0.07B0.14 metallic glass gaskets in XRD experiments for both axial and radial geometries substantially improves various aspects of megabar experiments and, in particular, the signal-to-noise ratio in comparison to that with conventional gaskets made of Re, W, steel or other crystalline metals.
  •  
23.
  • du Plessis, Hester Esna, et al. (författare)
  • Rietveld and pair distribution function study of Hagg carbide using synchrotron X-ray diffraction
  • 2011
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 18, s. 266-271
  • Tidskriftsartikel (refereegranskat)abstract
    • Fischer-Tropsch (FT) synthesis is an important process in the manufacturing of hydrocarbons and oxygenated hydrocarbons from mixtures of carbon monoxide and hydrogen (syngas). The reduced iron catalyst reacts with carbon monoxide and hydrogen to form bulk Fe5C2 Hagg carbide (chi-HC) during FT synthesis. Arguably, chi-HC is the predominant catalyst phase present in the working iron catalyst. Deactivation of the working catalyst can be due to oxidation of chi-HC to iron oxide, a step-wise decarburization to cementite (theta-Fe3C), carbon formation or sintering with accompanying loss of catalytic performance. It is therefore critical to determine the precise crystal structure of chi-HC for the understanding of the synthesis process and for comparison with the first-principles ab initio modelling. Here the results of high-resolution synchrotron X-ray powder diffraction data are reported. The atomic arrangement of chi-HC was confirmed by Rietveld refinement and subsequent real-space modelling of the pair distribution function (PDF) obtained from direct Fourier transformation. The Rietveld and PDF results of chi-HC correspond well with that of a pseudo-monoclinic phase of space group Pi [a = 11.5661 (6) A, b = 4.5709 (1) A, c = 5.0611 (2) A, alpha = 89.990 (5)degrees, beta = 97.753 (4)degrees, gamma = 90.195 (4)degrees], where the Fe atoms are located in three distorted prismatic trigonal and one octahedral arrangement around the central C atoms. The Fe atoms are distorted from the prismatic trigonal arrangement in the monoclinic structure by the change in C atom location in the structure.
  •  
24.
  • Dullin, Christian, et al. (författare)
  • Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography. - 0909-0495 .- 1600-5775. ; 22, s. 143-155
  • Tidskriftsartikel (refereegranskat)abstract
    • Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites.
  •  
25.
  • Dullin, Christian, et al. (författare)
  • Phase-contrast computed tomography for quantification of structural changes in lungs of asthma mouse models of different severity
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography. - 0909-0495 .- 1600-5775. ; 22, s. 1106-1111
  • Tidskriftsartikel (refereegranskat)abstract
    • Lung imaging in mouse disease models is crucial for the assessment of the severity of airway disease but remains challenging due to the small size and the high porosity of the organ. Synchrotron inline free-propagation phase-contrast computed tomography (CT) with its intrinsic high soft-tissue contrast provides the necessary sensitivity and spatial resolution to analyse the mouse lung structure in great detail. Here, this technique has been applied in combination with single-distance phase retrieval to quantify alterations of the lung structure in experimental asthma mouse models of different severity. In order to mimic an in vivo situation as close as possible, the lungs were inflated with air at a constant physiological pressure. Entire mice were embedded in agarose gel and imaged using inline free-propagation phase-contrast CT at the SYRMEP beamline (Synchrotron Light Source, Elettra, Trieste, Italy). The quantification of the obtained phase-contrast CT data sets revealed an increasing lung soft-tissue content in mice correlating with the degree of the severity of experimental allergic airways disease. In this way, it was possible to successfully discriminate between healthy controls and mice with either mild or severe allergic airway disease. It is believed that this approach may have the potential to evaluate the efficacy of novel therapeutic strategies that target airway remodelling processes in asthma.
  •  
26.
  • Einfeld, Dieter, et al. (författare)
  • First multi-bend achromat lattice consideration.
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21:Pt 5, s. 856-861
  • Tidskriftsartikel (refereegranskat)abstract
    • By the beginning of 1990, three third-generation synchrotron light sources had been successfully commissioned in Grenoble, Berkeley and Trieste (ESRF, ALS and ELETTRA). Each of these new machines reached their target specifications without any significant problems. In parallel, already at that time discussions were underway regarding the next generation, the `diffraction-limited light source (DLSR)', which featured sub-nm rad electron beam emittance, photon beam brilliance exceeding 10(22) and the potential to emit coherent radiation. Also, at about that time, a first design for a 3 GeV DLSR was developed, based on a modified multiple-bend achromat (MBA) design leading to a lattice with normalized emittance of ℇx = 0.5 nm rad. The novel feature of the MBA lattice was the use of seven vertically focusing bend magnets with different bending angles throughout the achromat cell to keep the radiation integrals and resulting beam emittance low. The baseline design called for a 400 m ring circumference with 12 straight sections of 6 m length. The dynamic aperture behaviour of the DLSR lattice was estimated to produce > 5 h beam lifetime at 100 mA stored beam current.
  •  
27.
  • Eriksson, Mikael, et al. (författare)
  • Diffraction-limited storage rings - a window to the science of tomorrow.
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21:Pt 5, s. 837-842
  • Tidskriftsartikel (refereegranskat)abstract
    • This article summarizes the contributions in this special issue on Diffraction-Limited Storage Rings. It analyses the progress in accelerator technology enabling a significant increase in brightness and coherent fraction of the X-ray light provided by storage rings. With MAX IV and Sirius there are two facilities under construction that already exploit these advantages. Several other projects are in the design stage and these will probably enhance the performance further. To translate the progress in light source quality into new science requires similar progress in aspects such as optics, beamline technology, detectors and data analysis. The quality of new science will be limited by the weakest component in this value chain. Breakthroughs can be expected in high-resolution imaging, microscopy and spectroscopy. These techniques are relevant for many fields of science; for example, for the fundamental understanding of the properties of correlated electron materials, the development and characterization of materials for data and energy storage, environmental applications and bio-medicine.
  •  
28.
  • Fernandes Tavares, Pedro, et al. (författare)
  • The MAX IV storage ring project.
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21:Pt 5, s. 862-877
  • Tidskriftsartikel (refereegranskat)abstract
    • The MAX IV facility, currently under construction in Lund, Sweden, features two electron storage rings operated at 3 GeV and 1.5 GeV and optimized for the hard X-ray and soft X-ray/VUV spectral ranges, respectively. A 3 GeV linear accelerator serves as a full-energy injector into both rings as well as a driver for a short-pulse facility, in which undulators produce X-ray pulses as short as 100 fs. The 3 GeV ring employs a multibend achromat (MBA) lattice to achieve, in a relatively short circumference of 528 m, a bare lattice emittance of 0.33 nm rad, which reduces to 0.2 nm rad as insertion devices are added. The engineering implementation of the MBA lattice raises several technological problems. The large number of strong magnets per achromat calls for a compact design featuring small-gap combined-function magnets grouped into cells and sharing a common iron yoke. The small apertures lead to a low-conductance vacuum chamber design that relies on the chamber itself as a distributed copper absorber for the heat deposited by synchrotron radiation, while non-evaporable getter (NEG) coating provides for reduced photodesorption yields and distributed pumping. Finally, a low main frequency (100 MHz) is chosen for the RF system yielding long bunches, which are further elongated by passively operated third-harmonic Landau cavities, thus alleviating collective effects, both coherent (e.g. resistive wall instabilities) and incoherent (intrabeam scattering). In this paper, we focus on the MAX IV 3 GeV ring and present the lattice design as well as the engineering solutions to the challenges inherent to such a design. As the first realisation of a light source based on the MBA concept, the MAX IV 3 GeV ring offers an opportunity for validation of concepts that are likely to be essential ingredients of future diffraction-limited light sources.
  •  
29.
  • Genuzio, Francesca, et al. (författare)
  • A UHV MOKE magnetometer complementing XMCD-PEEM at the Elettra Synchrotron
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 28, s. 995-1005
  • Tidskriftsartikel (refereegranskat)abstract
    • We report on a custom-built UHV-compatible Magneto-Optical Kerr Effect (MOKE) magnetometer for applications in surface and materials sciences, operating in tandem with the PhotoEmission Electron Microscope (PEEM) endstation at the Nanospectroscopy beamline of the Elettra synchrotron. The magnetometer features a liquid-nitrogen-cooled electromagnet that is fully compatible with UHV operation and produces magnetic fields up to about 140 mT at the sample. Longitudinal and polar MOKE measurement geometries are realized. The magneto-optical detection is based on polarization analysis using a photoelastic modulator. The sample manipulation system is fully compatible with that of the PEEM, making it possible to exchange samples with the beamline endstation, where complementary X-ray imaging and spectroscopy techniques are available. The magnetometer performance is illustrated by experiments on cobalt ultra-thin films, demonstrating close to monolayer sensitivity. The advantages of combining in situ growth, X-ray Magnetic Circular Dichroism imaging (XMCD-PEEM) and MOKE magnetometry into a versatile multitechnique facility are highlighted.
  •  
30.
  • Glazyrin, K., et al. (författare)
  • Sub-micrometer focusing setup for high-pressure crystallography at the Extreme Conditions beamline at PETRA III
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - Chichester, United Kingdom : Wiley-Blackwell. - 0909-0495 .- 1600-5775. ; 29, s. 654-663
  • Tidskriftsartikel (refereegranskat)abstract
    • Scientific tasks aimed at decoding and characterizing complex systems and processes at high pressures set new challenges for modern X-ray diffraction instrumentation in terms of X-ray flux, focal spot size and sample positioning. Presented here are new developments at the Extreme Conditions beamline (P02.2, PETRA III, DESY, Germany) that enable considerable improvements in data collection at very high pressures and small scattering volumes. In particular, the focusing of the X-ray beam to the sub-micrometer level is described, and control of the aberrations of the focusing compound refractive lenses is made possible with the implementation of a correcting phase plate. This device provides a significant enhancement of the signal-to-noise ratio by conditioning the beam shape profile at the focal spot. A new sample alignment system with a small sphere of confusion enables single-crystal data collection from grains of micrometer to sub-micrometer dimensions subjected to pressures as high as 200 GPa. The combination of the technical development of the optical path and the sample alignment system contributes to research and gives benefits on various levels, including rapid and accurate diffraction mapping of samples with sub-micrometer resolution at multimegabar pressures.
  •  
31.
  •  
32.
  • Grabski, Marek, et al. (författare)
  • Commissioning and operation status of the MAX IV 3 GeV storage ring vacuum system
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 28, s. 718-731
  • Tidskriftsartikel (refereegranskat)abstract
    • The 3 GeV electron storage ring of the MAX IV laboratory is the first storage-ring-based synchrotron radiation facility with the inner surface of almost all the vacuum chambers along its circumference coated with non-evaporable getter (NEG) thin film. The coating provides a low dynamic outgassing rate and pumping of active gases. As the NEG coating was applied on an unprecedented scale, there were doubts concerning the storage ring performance. Fast conditioning of the vacuum system and over five years of reliable accelerator operation have demonstrated that the chosen design proved to be good and does not impose limits on the operation. The vacuum system performance is comparable with or better than that of other similar facilities around the world, where conventional designs were implemented. Observed pressure levels are low, and the electron beam lifetime is long and not limited by residual gas density. A summary of the vacuum performance is presented.
  •  
33.
  • Guizar-Sicairos, Manuel, et al. (författare)
  • Validation study of small-angle X-ray scattering tensor tomography
  • 2020
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775 .- 0909-0495. ; 27, s. 779-787
  • Tidskriftsartikel (refereegranskat)abstract
    • Small-angle scattering tensor tomography (SASTT) is a recently developed technique able to tomographically reconstruct the 3D reciprocal space from voxels within a bulk volume. SASTT extends the concept of X-ray computed tomography, which typically reconstructs scalar values, by reconstructing a tensor per voxel, which represents the local nanostructure 3D organization. In this study, the nanostructure orientation in a human trabecular-bone sample obtained by SASTT was validated by sectioning the sample and using 3D scanning small-angle X-ray scattering (3D sSAXS) to measure and analyze the orientation from single voxels within each thin section. Besides the presence of cutting artefacts from the slicing process, the nanostructure orientations obtained with the two independent methods were in good agreement, as quantified with the absolute value of the dot product calculated between the nanostructure main orientations obtained in each voxel. The average dot product per voxel over the full sample containing over 10 000 voxels was 0.84, and in six slices, in which fewer cutting artefacts were observed, the dot product increased to 0.91. In addition, SAXS tensor tomography not only yields orientation information but can also reconstruct the full 3D reciprocal-space map. It is shown that the measured anisotropic scattering for individual voxels was reproduced from the SASTT reconstruction in each voxel of the 3D sample. The scattering curves along different 3D directions are validated with data from single voxels, demonstrating SASTT's potential for a separate analysis of nanostructure orientation and structural information from the angle-dependent intensity distribution.
  •  
34.
  • Hatakada, K, et al. (författare)
  • Theoretical study of the non-local optical potential in EXAFS spectra
  • 2001
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 8:2, s. 207-209
  • Tidskriftsartikel (refereegranskat)abstract
    • We study the optical potential effects on the extended x-ray absorption fine structure (EXAFS) and x-ray photoelectron diffraction (XPD) spectra. For the valence electron optical potential we use a local density approximation because the charge density changes fairly slowly, whereas we use a non-local optical potential for the core electron part based on GW-approximation. In the Br K-edge EXAFS spectra the present optical potential gives rise to the phase difference and the amplitude reduction; the agreement with the experimental result is excellent. In the N-1s XPD spectra for N2/Ni(100), the spherical wave effects enhance the effects due to the optical potential.(19 refs)
  •  
35.
  • Hatakada, K., et al. (författare)
  • Theory of spin-polarized optical potential
  • 2001
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; , s. 210-212
  • Tidskriftsartikel (refereegranskat)abstract
    • We develop an approximation for the non-local spin-polarized optical potential theory for atoms in solids at intermediate and high energy. The present approximation for the optical potential builds on the GW-expression. We separate the RPA polarization propagator into a core electron and a valence electron part, and can then achieve a corresponding separation of the optical potential. For the valence electron optical potential we use a local density approximation because the charge density changes fairly slowly, whereas we use a non-local optical potential for the core electron part. Both of them depend on the spin-polarization. We apply this method to electron-Fe elastic scattering in solids, and discuss the results.(16 refs)
  •  
36.
  • Jensen, Alexander Bernthz, et al. (författare)
  • Very large-scale diffraction investigations enabled by a matrix-multiplication facilitated radial and azimuthal integration algorithm : MatFRAIA
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 29, s. 1420-1428
  • Tidskriftsartikel (refereegranskat)abstract
    • As synchrotron facilities continue to generate increasingly brilliant X-rays and detector speeds increase, swift data reduction from the collected area detector images to more workable 1D diffractograms becomes of increasing importance. This work reports an integration algorithm that can integrate diffractograms in real time on modern laptops and can reach 10 kHz integration speeds on modern workstations using an efficient pixel-splitting and parallelization scheme. This algorithm is limited not by the computation of the integration itself but is rather bottlenecked by the speed of the data transfer to the processor, the data decompression and/or the saving of results. The algorithm and its implementation is described while the performance is investigated on 2D scanning X-ray diffraction/fluorescence data collected at the interface between an implant and forming bone.
  •  
37.
  • Jensen, Maja, 1978, et al. (författare)
  • High-resolution macromolecular crystallography at the FemtoMAX beamline with time-over-threshold photon detection
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775 .- 0909-0495. ; 28, s. 64-70
  • Tidskriftsartikel (refereegranskat)abstract
    • Protein dynamics contribute to protein function on different time scales. Ultrafast X-ray diffraction snapshots can visualize the location and amplitude of atom displacements after perturbation. Since amplitudes of ultrafast motions are small, high-quality X-ray diffraction data is necessary for detection. Diffraction from bovine trypsin crystals using single femtosecond X-ray pulses was recorded at FemtoMAX, which is a versatile beamline of the MAX IV synchrotron. The time-over-threshold detection made it possible that single photons are distinguishable even under short-pulse low-repetition-rate conditions. The diffraction data quality from FemtoMAX beamline enables atomic resolution investigation of protein structures. This evaluation is based on the shape of the Wilson plot, cumulative intensity distribution compared with theoretical distribution, I/σ, Rmerge /Rmeas and CC1/2 statistics versus resolution. The FemtoMAX beamline provides an interesting alternative to X-ray free-electron lasers when studying reversible processes in protein crystals.
  •  
38.
  • Johansson, Martin, et al. (författare)
  • Magnet design for a low-emittance storage ring.
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21:Pt 5, s. 884-903
  • Tidskriftsartikel (refereegranskat)abstract
    • The MAX IV 3 GeV storage ring, currently under construction, pursues the goal of low electron beam emittance by using a multi-bend achromat magnet lattice, which is realised by having several consecutive magnet elements precision-machined out of a common solid iron block, 2.3-3.4 m long. With this magnet design solution, instead of having 1320 individual magnets, the MAX IV 3 GeV storage ring is built up using 140 integrated `magnet block' units, containing all these magnet elements. Major features of this magnet block design are compactness, vibration stability and that the alignment of magnet elements within each unit is given by the mechanical accuracy of the CNC machining rather than individual field measurement and adjustment. This article presents practical engineering details of implementing this magnet design solution, and mechanical + magnetic field measurement results from the magnet production series. At the time of writing (spring 2014), the production series, which is totally outsourced to industry, is roughly half way through, with mechanical/magnetic QA conforming to specifications. It is the conclusion of the authors that the MAX IV magnet block concept, which has sometimes been described as new or innovative, is from a manufacturing point of view simply a collection of known mature production methods and measurement procedures, which can be executed at fixed cost with a low level of risk.
  •  
39.
  • Johansson, Ulf, et al. (författare)
  • NanoMAX : the hard X-ray nanoprobe beamline at the MAX IV Laboratory
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 28, s. 1935-1947
  • Tidskriftsartikel (refereegranskat)abstract
    • NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world's first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.
  •  
40.
  • Juanhuix, Jordi, et al. (författare)
  • Developments in optics and performance at BL13-XALOC, the macromolecular crystallography beamline at the Alba Synchrotron
  • 2014
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 21, s. 679-689
  • Tidskriftsartikel (refereegranskat)abstract
    • BL13-XALOC is currently the only macromolecular crystallography beamline at the 3 GeV ALBA synchrotron near Barcelona, Spain. The optics design is based on an in-vacuum undulator, a Si(111) channel-cut crystal monochromator and a pair of KB mirrors. It allows three main operation modes: a focused configuration, where both mirrors can focus the beam at the sample position to 52 mu m x 5.5 mu m FWHM(H x V); a defocused configuration that can match the size of the beam to the dimensions of the crystals or to focus the beam at the detector; and an unfocused configuration, where one or both mirrors are removed from the photon beam path. To achieve a uniform defocused beam, the slope errors of the mirrors were reduced down to 55 nrad RMS by employing a novel method that has been developed at the ALBA high-accuracy metrology laboratory. Thorough commissioning with X-ray beam and user operation has demonstrated an excellent energy and spatial stability of the beamline. The end-station includes a high-accuracy single-axis diffractometer, a removable mini-kappa stage, an automated sample-mounting robot and a photon-counting detector that allows shutterless operation. The positioning tables of the diffractometer and the detector are based on a novel and highly stable design. This equipment, together with the operation flexibility of the beamline, allows a large variety of types of crystals to be tackled, from medium-sized crystals with large unit-cell parameters to microcrystals. Several examples of data collections measured during beamline commissioning are described. The beamline started user operation on 18 July 2012.
  •  
41.
  • Jönsson, H. Olof, et al. (författare)
  • Simulations of Radiation Damage as a Function of the Temporal Pulse Profile in Femtosecond X-ray Protein Crystallography
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - 0909-0495 .- 1600-5775. ; 22:2, s. 256-266
  • Tidskriftsartikel (refereegranskat)abstract
    • Serial femtosecond X-ray crystallography of protein nanocrystals using ultrashort and intense pulses from an X-ray free-electron laser has proved to be a successful method for structural determination. However, due to significant variations in diffraction pattern quality from pulse to pulse only a fraction of the collected frames can be used. Experimentally, the X-ray temporal pulse profile is not known and can vary with every shot. This simulation study describes how the pulse shape affects the damage dynamics, which ultimately affects the biological interpretation of electron density. The instantaneously detected signal varies during the pulse exposure due to the pulse properties, as well as the structural and electronic changes in the sample. Here ionization and atomic motion are simulated using a radiation transfer plasma code. Pulses with parameters typical for X-ray free-electron lasers are considered: pulse energies ranging from 10$\sp 4$ to 10$\sp 7$Jcm$\sp $-$2$ with photon energies from 2 to 12keV, up to 100fs long. Radiation damage in the form of sample heating that will lead to a loss of crystalline periodicity and changes in scattering factor due to electronic reconfigurations of ionized atoms are considered here. The simulations show differences in the dynamics of the radiation damage processes for different temporal pulse profiles and intensities, where ionization or atomic motion could be predominant. The different dynamics influence the recorded diffracted signal in any given resolution and will affect the subsequent structure determination.
  •  
42.
  • Kalbfleisch, Sebastian, et al. (författare)
  • X-ray in-line holography and holotomography at the NanoMAX beamline
  • 2022
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 0909-0495 .- 1600-5775. ; 29, s. 224-229
  • Tidskriftsartikel (refereegranskat)abstract
    • Coherent X-ray imaging techniques, such as in-line holography, exploit the high brilliance provided by diffraction-limited storage rings to perform imaging sensitive to the electron density through contrast due to the phase shift, rather than conventional attenuation contrast. Thus, coherent X-ray imaging techniques enable high-sensitivity and low-dose imaging, especially for low-atomic-number (Z) chemical elements and materials with similar attenuation contrast. Here, the first implementation of in-line holography at the NanoMAX beamline is presented, which benefits from the exceptional focusing capabilities and the high brilliance provided by MAX IV, the first operational diffractionlimited storage ring up to approximately 300 eV. It is demonstrated that in-line holography at NanoMAX can provide 2D diffraction-limited images, where the achievable resolution is only limited by the 70 nm focal spot at 13 keV X-ray energy. Also, the 3D capabilities of this instrument are demonstrated by performing holotomography on a chalk sample at a mesoscale resolution of around 155 nm. It is foreseen that in-line holography will broaden the spectra of capabilities of MAX IV by providing fast 2D and 3D electron density images from mesoscale down to nanoscale resolution.
  •  
43.
  • Keplinger, Mario, et al. (författare)
  • X-ray diffraction strain analysis of a single axial InAs1-xPx nanowire segment.
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 22:Pt 1, s. 59-66
  • Tidskriftsartikel (refereegranskat)abstract
    • The spatial strain distribution in and around a single axial InAs1-xPx hetero-segment in an InAs nanowire was analyzed using nano-focused X-ray diffraction. In connection with finite-element-method simulations a detailed quantitative picture of the nanowire's inhomogeneous strain state was achieved. This allows for a detailed understanding of how the variation of the nanowire's and hetero-segment's dimensions affect the strain in its core region and in the region close to the nanowire's side facets. Moreover, ensemble-averaging high-resolution diffraction experiments were used to determine statistical information on the distribution of wurtzite and zinc-blende crystal polytypes in the nanowires.
  •  
44.
  • Ketenoglu, Didem, et al. (författare)
  • Resonant inelastic X-ray scattering spectrometer with 25 meV resolution at the Cu K-edge
  • 2015
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 22, s. 961-967
  • Tidskriftsartikel (refereegranskat)abstract
    • An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the Cu K-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO2) pixels, the spectrometer delivers a resolution near 25 meV (FWHM) at 8981 eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick-Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal.
  •  
45.
  • Knaapila, Matti, et al. (författare)
  • A new small-angle X-ray scattering set-up on the crystallography beamline I711 at MAX-lab.
  • 2009
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 16:Pt 4, s. 498-504
  • Tidskriftsartikel (refereegranskat)abstract
    • A small-angle X-ray scattering (SAXS) set-up has recently been developed at beamline I711 at the MAX II storage ring in Lund (Sweden). An overview of the required modifications is presented here together with a number of application examples. The accessible q range in a SAXS experiment is 0.009-0.3 A(-1) for the standard set-up but depends on the sample-to-detector distance, detector offset, beamstop size and wavelength. The SAXS camera has been designed to have a low background and has three collinear slit sets for collimating the incident beam. The standard beam size is about 0.37 mm x 0.37 mm (full width at half-maximum) at the sample position, with a flux of 4 x 10(10) photons s(-1) and lambda = 1.1 A. The vacuum is of the order of 0.05 mbar in the unbroken beam path from the first slits until the exit window in front of the detector. A large sample chamber with a number of lead-throughs allows different sample environments to be mounted. This station is used for measurements on weakly scattering proteins in solutions and also for colloids, polymers and other nanoscale structures. A special application supported by the beamline is the effort to establish a micro-fluidic sample environment for structural analysis of samples that are only available in limited quantities. Overall, this work demonstrates how a cost-effective SAXS station can be constructed on a multipurpose beamline.
  •  
46.
  • Kokkonen, Esko, et al. (författare)
  • Upgrade of the SPECIES beamline at the MAX IV Laboratory
  • 2021
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 28, s. 588-601
  • Tidskriftsartikel (refereegranskat)abstract
    • The SPECIES beamline has been transferred to the new 1.5 GeV storage ring at the MAX IV Laboratory. Several improvements have been made to the beamline and its endstations during the transfer. Together the Ambient Pressure X-ray Photoelectron Spectroscopy and Resonant Inelastic X-ray Scattering endstations are capable of conducting photoelectron spectroscopy in elevated pressure regimes with enhanced time-resolution and flux and X-ray scattering experiments with improved resolution and flux. Both endstations offer a unique capability for experiments at low photon energies in the vacuum ultraviolet and soft X-ray range. In this paper, the upgrades on the endstations and current performance of the beamline are reported.
  •  
47.
  • Kristiansen, Paw, et al. (författare)
  • Vibrational stability of a cryocooled horizontal double-crystal monochromator
  • 2016
  • Ingår i: Journal of Synchrotron Radiation. - 1600-5775. ; 23:Pt 5, s. 1076-1081
  • Tidskriftsartikel (refereegranskat)abstract
    • The vibrational stability of a horizontally deflecting double-crystal monochromator (HDCM) is investigated. Inherently a HDCM will preserve the vertical beam stability better than a `normal' vertical double-crystal monochromator as the vibrations of a HDCM will almost exclusively affect the horizontal stability. Here both the relative pitch vibration between the first and second crystal and the absolute pitch vibration of the second crystal are measured. All reported measurements are obtained under active cooling by means of flowing liquid nitrogen (LN2). It is found that it is favorable to circulate the LN2 at high pressures and low flow rates (up to 5.9 bar and down to 3 l min(-1) is tested) to attain low vibrations. An absolute pitch stability of the second crystal of 18 nrad RMS, 2-2500 Hz, and a relative pitch stability between the two crystals of 25 nrad RMS, 1-2500 Hz, is obtained under cryocooling conditions that allow for 1516 W to be adsorbed by the LN2 before it vaporizes.
  •  
48.
  • Kubo, M., et al. (författare)
  • Nanosecond pump-probe device for time-resolved serial femtosecond crystallography developed at SACLA
  • 2017
  • Ingår i: Journal of Synchrotron Radiation. - : International Union of Crystallography (IUCr). - 1600-5775. ; 24, s. 1086-1091
  • Tidskriftsartikel (refereegranskat)abstract
    • X-ray free-electron lasers (XFELs) have opened new opportunities for timeresolved X-ray crystallography. Here a nanosecond optical-pump XFEL-probe device developed for time-resolved serial femtosecond crystallography (TRSFX) studies of photo-induced reactions in proteins at the SPring-8 Angstrom Compact free-electron LAser (SACLA) is reported. The optical-fiber-based system is a good choice for a quick setup in a limited beam time and allows pump illumination from two directions to achieve high excitation efficiency of protein microcrystals. Two types of injectors are used: one for extruding highly viscous samples such as lipidic cubic phase (LCP) and the other for pulsed liquid droplets. Under standard sample flow conditions from the viscous-sample injector, delay times from nanoseconds to tens of milliseconds are accessible, typical time scales required to study large protein conformational changes. A first demonstration of a TR-SFX experiment on bacteriorhodopsin in bicelle using a setup with a droplet-type injector is also presented.
  •  
49.
  • Kubo, Minoru, et al. (författare)
  • Nanosecond pump-probe device for time-resolved serial femtosecond crystallography developed at SACLA
  • 2017
  • Ingår i: Journal of Synchrotron Radiation. - : INT UNION CRYSTALLOGRAPHY. - 0909-0495 .- 1600-5775. ; 24, s. 1086-1091
  • Tidskriftsartikel (refereegranskat)abstract
    • X-ray free-electron lasers (XFELs) have opened new opportunities for timeresolved X-ray crystallography. Here a nanosecond optical-pump XFEL-probe device developed for time-resolved serial femtosecond crystallography (TRSFX) studies of photo-induced reactions in proteins at the SPring-8 Angstrom Compact free-electron LAser (SACLA) is reported. The optical-fiber-based system is a good choice for a quick setup in a limited beam time and allows pump illumination from two directions to achieve high excitation efficiency of protein microcrystals. Two types of injectors are used: one for extruding highly viscous samples such as lipidic cubic phase (LCP) and the other for pulsed liquid droplets. Under standard sample flow conditions from the viscous-sample injector, delay times from nanoseconds to tens of milliseconds are accessible, typical time scales required to study large protein conformational changes. A first demonstration of a TR-SFX experiment on bacteriorhodopsin in bicelle using a setup with a droplet-type injector is also presented.
  •  
50.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 101
Typ av publikation
tidskriftsartikel (101)
Typ av innehåll
refereegranskat (100)
övrigt vetenskapligt/konstnärligt (1)
Författare/redaktör
Kahnt, Maik (5)
Caleman, Carl (5)
Graafsma, Heinz (5)
Johansson, Ulf (4)
Såthe, Conny (4)
Sjöblom, Peter (4)
visa fler...
Knudsen, Jan (4)
Sala, Simone (4)
Agåker, Marcus (3)
Åhnberg, Karl (3)
Svensson, Christer (3)
Urpelainen, Samuli (3)
Bonetti, Stefano (3)
Boutet, Sébastien (3)
Thunnissen, Marjolei ... (3)
Sá, Jacinto (2)
Szlachetko, Jakub (2)
Dubrovinskaia, Natal ... (2)
Lange, S. (2)
Claesson, Per M. (2)
Andersen, Jesper N (2)
Gustafson, Johan (2)
Carlson, Stefan (2)
Wallentin, Jesper (2)
Labrador, Ana (2)
Butorin, Sergei (2)
Norsk Jensen, Brian (2)
Söderberg, Daniel (2)
Luo, Yi (2)
Vogt, Ulrich (2)
Al Dmour, Eshraq (2)
Einfeld, Dieter (2)
Fernandes Tavares, P ... (2)
Grabski, Marek (2)
Cerenius, Yngve (2)
Kloos, Marco (2)
Marras, A. (2)
Zimmer, M. (2)
Kuhn, Manuela (2)
Marras, Alessandro (2)
Mozzanica, Aldo (2)
Schmitt, Bernd (2)
Zimmer, Manfred (2)
Lange, Sabine (2)
Appio, Roberto (2)
Hedin, Lars (2)
Almer, J (2)
Alonso-Mori, Roberto (2)
Steuwer, Axel (2)
Correa, J. (2)
visa färre...
Lärosäte
Lunds universitet (47)
Uppsala universitet (29)
Kungliga Tekniska Högskolan (14)
Stockholms universitet (8)
Linköpings universitet (6)
Mittuniversitetet (6)
visa fler...
Chalmers tekniska högskola (6)
RISE (4)
Göteborgs universitet (3)
Högskolan i Halmstad (2)
Malmö universitet (2)
Karolinska Institutet (2)
Umeå universitet (1)
Högskolan i Gävle (1)
Sveriges Lantbruksuniversitet (1)
visa färre...
Språk
Engelska (101)
Forskningsämne (UKÄ/SCB)
Naturvetenskap (96)
Teknik (7)
Medicin och hälsovetenskap (6)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy