Energy-dispersive Laue diffraction by means of a pnCCD detector coupled to a CsI(Tl) scintillator using ultra-hard X-ray synchrotron radiation

2019 ◽  
Vol 26 (5) ◽  
pp. 1612-1620
Author(s):  
Mohammad Shokr ◽  
Amir Tosson ◽  
Ali Abboud ◽  
Alaa Algashi ◽  
Dieter Schlosser ◽  
...  
Keyword(s):  
Detection System ◽  
Unit Cell ◽  
Lattice Parameters ◽  
Energy Dispersive ◽  
Mean Deviation ◽  
X Rays ◽  
Laue Diffraction ◽  
High Quantum Efficiency ◽  
X Ray ◽  
Cell Parameters

The lattice parameters and unit-cell orientation of an SrLaAlO4 crystal have been determined by means of energy-dispersive X-ray Laue diffraction (EDLD) using a pnCCD detector coupled to a columnar structure CsI(Tl) scintillator in the energy range between 40 and 130 keV. By exploiting the high quantum efficiency (QE) achieved by this combined detection system for hard X-rays, a large number of Bragg reflections could be recorded by the relatively small detector area, allowing accurate and fast determination of the lattice parameters and the moduli of the structure factors. The experiment was performed on the energy-dispersive diffraction (EDDI) beamline at the BESSY II synchrotron using a pnCCD detector with 128 × 128 pixels. Since the energies and positions of the Laue peaks can be recorded simultaneously by the pnCCD system, the tetragonal structure of the investigated specimen was determined without any prior information. The unit-cell parameters and the angles between the lattice vectors were evaluated with an accuracy of better than 0.7%, while the structure-factor moduli of the reflections were determined with a mean deviation of 2.5% relative to the theoretical values.

Application of a pnCCD for energy-dispersive Laue diffraction with ultra-hard X-rays

2016 ◽  
Vol 49 (1) ◽  
pp. 222-233 ◽  
Author(s):  
Sebastian Send ◽  
Ali Abboud ◽  
Nadja Wiesner ◽  
Mohammad Shokr ◽  
Manuela Klaus ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Relative Energy ◽  
Energy Dispersive ◽  
Laue Pattern ◽  
Single Shot ◽  
X Rays ◽  
Oriented Sample ◽  
Laue Diffraction ◽  
Cell Parameters ◽  
Structure Factors

In this work the spectroscopic performance of a pnCCD detector in the ultra-hard energy range between 40 and 140 keV is tested by means of an energy-dispersive Laue diffraction experiment on a GaAs crystal. About 100 Bragg peaks were collected in a single-shot exposure of the arbitrarily oriented sample to white synchrotron radiation provided by a wiggler at BESSY II and resolved in a large reciprocal-space volume. The positions and energies of individual Laue spots could be determined with a spatial accuracy of less than one pixel and a relative energy resolution better than 1%. In this way the unit-cell parameters of GaAs were extracted with an accuracy of 0.5%, allowing for a complete indexing of the recorded Laue pattern. Despite the low quantum efficiency of the pnCCD (below 7%), experimental structure factors could be obtained from the three-dimensional data sets, taking into account photoelectric absorption as well as Compton scattering processes inside the detector. The agreement between measured and theoretical kinematical structure factors calculated from the known crystal structure is of the order of 10%. The results of this experiment demonstrate the potential of pnCCD detectors for applications in X-ray structure analysis using the complete energy spectrum of synchrotron radiation.

Crystallization and preliminary X-ray analysis of a complex between the Bowman–Birk trypsin inhibitor from barley and porcine pancreatic trypsin

1999 ◽  
Vol 55 (6) ◽  
pp. 1244-1246 ◽  
Author(s):  
Young Sil Kim ◽  
Hyun Kyu Song ◽  
Se Won Suh
Keyword(s):  
Polyethylene Glycol ◽  
Trypsin Inhibitor ◽  
Unit Cell ◽  
X Rays ◽  
Asymmetric Unit ◽  
Unit Cell Parameters ◽  
Orthorhombic Space Group ◽  
Solvent Content ◽  
X Ray ◽  
Cell Parameters

A 1:2 complex between the Bowman–Birk trypsin inhibitor from barley seeds and porcine pancreatic trypsin has been crystallized at 291 K using polyethylene glycol as precipitant. The crystals belong to the orthorhombic space group P212121, with unit-cell parameters a = 67.10, b = 88.38 and c = 203.65 Å. The asymmetric unit contains two monomers of the complex, with a corresponding Vm of 2.41 Å3 Da−1 and a solvent content of 49%. Native data to 2.2 Å resolution have been collected at 100 K using synchrotron X-rays.

scholarly journals Neutron and X-ray analysis of the Fenna–Matthews–Olson photosynthetic antenna complex from Prosthecochloris aestuarii

2019 ◽  
Vol 75 (3) ◽  
pp. 171-175
Author(s):  
Xun Lu ◽  
Brinda Selvaraj ◽  
Sudipa Ghimire-Rijal ◽  
Gregory S. Orf ◽  
Flora Meilleur ◽  
...  
Keyword(s):  
High Resolution ◽  
Direct Determination ◽  
Unit Cell ◽  
X Rays ◽  
Excitation Energies ◽  
X Ray ◽  
Cell Parameters ◽  
Antenna Complex ◽  
Prosthecochloris Aestuarii ◽  
Photosynthetic Antenna

The Fenna–Matthews–Olson protein from Prosthecochloris aestuarii (PaFMO) has been crystallized in a new form that is amenable to high-resolution X-ray and neutron analysis. The crystals belonged to space group H3, with unit-cell parameters a = b = 83.64, c = 294.78 Å, and diffracted X-rays to ∼1.7 Å resolution at room temperature. Large PaFMO crystals grown to volumes of 0.3–0.5 mm3 diffracted neutrons to 2.2 Å resolution on the MaNDi neutron diffractometer at the Spallation Neutron Source. The resolution of the neutron data will allow direct determination of the positions of H atoms in the structure, which are believed to be fundamentally important in tuning the individual excitation energies of bacteriochlorophylls in this archetypal photosynthetic antenna complex. This is one of the largest unit-cell systems yet studied using neutron diffraction, and will allow the first high-resolution neutron analysis of a photosynthetic antenna complex.

Crystallization and preliminary X-ray analyses of catabolite control protein A, free and in complex with its DNA-binding site

2000 ◽  
Vol 56 (1) ◽  
pp. 67-69 ◽  
Author(s):  
Jan Tebbe ◽  
Peter Orth ◽  
Elke Küster-Schöck ◽  
Wolfgang Hillen ◽  
Wolfram Saenger ◽  
...  
Keyword(s):  
Protein A ◽  
Unit Cell ◽  
X Rays ◽  
Asymmetric Unit ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Control Protein ◽  
Catabolite Control

The catabolite control protein (CcpA) from Bacillus megaterium is a member of the bacterial repressor protein family GalR/LacI. CcpA with an N-terminal His-tag was used for crystallization. Crystals of free CcpA and of CcpA in complex with the putative operator sequence (catabolite responsive elements, CRE) were obtained by vapour-diffusion techniques at 291 K using the hanging-drop method. CcpA crystals grown in the presence of polyethylene glycol 8000 belong to the hexagonal space group P6122 or P6522, with unit-cell parameters a = 74.4, c = 238.8 Å. These crystals diffract X-rays to 2.55 Å resolution and contain one monomer of the homodimeric protein per asymmetric unit. Crystals of the CcpA–CRE complex were obtained with ammonium sulfate as precipitant and belong to the tetragonal space group I4122, with unit-cell parameters a = 125, c = 400 Å and one complex per asymmetric unit. Although these co-crystals grew to a sufficient size, X-ray diffraction was limited to 8 Å resolution.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

VHCF damage in duplex stainless steel revealed by microbeam energy-dispersive X-ray Laue diffraction

2021 ◽  
pp. 106358
Author(s):  
Ali Abboud ◽  
Ali AlHassan ◽  
Benjamin Dönges ◽  
Jean Sebastian Micha ◽  
Robert Hartmann ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Energy Dispersive ◽  
Laue Diffraction ◽  
X Ray

scholarly journals Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Electron Probe ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Large Unit Cell ◽  
A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

Compressibility of β-As4S4: an in situ high-pressure single-crystal X-ray study

2012 ◽  
Vol 76 (4) ◽  
pp. 963-973 ◽  
Author(s):  
G. O. Lepore ◽  
T. Boffa Ballaran ◽  
F. Nestola ◽  
L. Bindi ◽  
D. Pasqual ◽  
...  
Keyword(s):  
Pressure Range ◽  
Substantial Reduction ◽  
Structural Data ◽  
Unit Cell ◽  
Van Der Waals Interactions ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Intermolecular Distances

AbstractAmbient temperature X-ray diffraction data were collected at different pressures from two crystals of β-As4S4, which were made by heating realgar under vacuum at 295ºC for 24 h. These data were used to calculate the unit-cell parameters at pressures up to 6.86 GPa. Above 2.86 GPa, it was only possible to make an approximate measurement of the unit-cell parameters. As expected for a crystal structure that contains molecular units held together by weak van der Waals interactions, β-As4S4 has an exceptionally high compressibility. The compressibility data were fitted to a third-order Birch–Murnaghan equation of state with a resulting volume V0 = 808.2(2) Å3, bulk modulus K0 = 10.9(2) GPa and K' = 8.9(3). These values are extremely close to those reported for the low-temperature polymorph of As4S4, realgar, which contains the same As4S4 cage-molecule. Structural analysis showed that the unit-cell contraction is due mainly to the reduction in intermolecular distances, which causes a substantial reduction in the unit-cell volume (∼21% at 6.86 GPa). The cage-like As4S4 molecules are only slightly affected. No phase transitions occur in the pressure range investigated.Micro-Raman spectra, collected across the entire pressure range, show that the peaks associated with As–As stretching have the greatest pressure dependence; the S–As–S bending frequency and the As–S stretching have a much weaker dependence or no variation at all as the pressure increases; this is in excellent agreement with the structural data.

Crystallization and preliminary X-ray studies of sialidase L from the leech Macrobdella decora

1998 ◽  
Vol 54 (1) ◽  
pp. 111-113 ◽  
Author(s):  
Yu Luo ◽  
Min-yuan Chou ◽  
Su-chen Li ◽  
Yu-teh Li ◽  
Ming Luo
Keyword(s):  
Escherichia Coli ◽  
Unit Cell ◽  
Data Sets ◽  
Molecular Replacement ◽  
Unit Cell Parameters ◽  
Solvent Content ◽  
X Ray ◽  
Cell Parameters ◽  
Mercury Derivative ◽  
Macrobdella Decora

Functional monomeric 83 kDa sialidase L, a NeuAcα2→3Gal-specific sialidase from Macrobdella leech, was expressed in Escherichia coli and readily crystallized by a macroseeding technique. The crystal belongs to space group P1 with unit-cell parameters a = 46.4, b = 69.3, c = 72.5 Å, α = 113.5, β = 95.4 and γ = 107.3°. There is one molecule per unit cell, giving a Vm = 2.4 Å3 Da−1 and a solvent content of 40%. Native and mercury-derivative data sets were collected to 2.0 Å resolution. Threading and molecular-replacement calculations confirmed the existence of a bacterial sialidase-like domain.

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