scholarly journals Determination of Structure Factors by the Pendellosung Effect for Imperfect Crystals

1988 ◽  
Vol 41 (3) ◽  
pp. 519
Author(s):  
NM Olekhnovich
Keyword(s):  
Tilt Angle ◽  
Oscillation Period ◽  
Waller Factor ◽  
X Ray ◽  
Method Of Determination ◽  
Debye Waller Factor ◽  
Structure Factors ◽  
Integrated Intensity ◽  
Coulomb Type

An investigation of thickness dependence of the X-ray integrated intensity of monochromatic linearly polarised X-ray radiation in a symmetrical Laue-case diffraction reveals that the method of determination of structure factors f from thickness oscillations can be extended to real crystals with a static distribution of Coulomb-type defects or dislocations. The f E value (where E is the static Debye-Waller factor) is determined from the oscillation period, while E is determined from the tilt-angle tangent of the oscillation axis of the reduced integrated intensity.

Determination of Composition and Linear Lattice Expansion Coefficient in Si1−x Gex/Si Thin Films by Simulation of X-Ray Rocking Curves

1990 ◽  
Vol 208 ◽  
Author(s):  
F. Cembali ◽  
R. Fabbri ◽  
M. Servidori ◽  
A. Zani ◽  
S. Iyer
Keyword(s):  
Thin Films ◽  
Expansion Coefficient ◽  
Molecular Beam ◽  
Depth Distribution ◽  
Waller Factor ◽  
Lattice Expansion ◽  
Linear Lattice ◽  
X Ray ◽  
Debye Waller Factor

ABSTRACTBy simulation of X-ray rocking curves of Si-Ge alloys grown on Si by molecular beam epitaxy and of Ge implanted samples, the Ge composition, the linear lattice expansion coefficient, the strain depth-distribution and the static Debye-Waller factor in the MBE alloys have been determined.

Development of a method for multielemental determination in water by EDXRF with radioisotopic source of 238Pu.

2019 ◽  
Vol 7 (2A) ◽  
Author(s):  
Camilo Fuentes Serrano ◽  
Juan Reinaldo Estevez Alvares ◽  
Alfredo Montero Alvarez ◽  
Ivan Pupo Gonzales ◽  
Zahily Herrero Fernandez ◽  
...  
Keyword(s):  
Thin Layer ◽  
Expanded Uncertainty ◽  
Considerable Decrease ◽  
X Ray ◽  
Precipitation Efficiency ◽  
Method Of Determination ◽  
Sensitivity Curves ◽  
Order Of Magnitude ◽  
Metrological Parameters

A method for determination of Cr, Fe, Co, Ni, Cu, Zn, Hg and Pb in waters by Energy Dispersive X Ray Fluorescence (EDXRF) was implemented, using a radioisotopic source of 238Pu. For previous concentration was employed a procedure including a coprecipitation step with ammonium pyrrolidinedithiocarbamate (APDC) as quelant agent, the separation of the phases by filtration, the measurement of filter by EDXRF and quantification by a thin layer absolute method. Sensitivity curves for K and L lines were obtained respectively. The sensitivity for most elements was greater by an order of magnitude in the case of measurement with a source of 238Pu instead of 109Cd, which means a considerable decrease in measurement times. The influence of the concentration in the precipitation efficiency was evaluated for each element. In all cases the recoveries are close to 100%, for this reason it can be affirmed that the method of determination of the studied elements is quantitative. Metrological parameters of the method such as trueness, precision, detection limit and uncertainty were calculated. A procedure to calculate the uncertainty of the method was elaborated; the most significant source of uncertainty for the thin layer EDXRF method is associated with the determination of instrumental sensitivities. The error associated with the determination, expressed as expanded uncertainty (in %), varied from 15.4% for low element concentrations (2.5-5 μg/L) to 5.4% for the higher concentration range (20-25 μg/L).

scholarly journals Atomic structure and phason modes of the Sc–Zn icosahedral quasicrystal

IUCrJ ◽  
2016 ◽  
Vol 3 (4) ◽  
pp. 247-258 ◽  
Author(s):  
Tsunetomo Yamada ◽  
Hiroyuki Takakura ◽  
Holger Euchner ◽  
Cesar Pay Gómez ◽  
Alexei Bosak ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Diffuse Scattering ◽  
Waller Factor ◽  
Close Packing ◽  
Icosahedral Quasicrystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Atom ◽  
Debye Waller Factor ◽  
The Difference

The detailed atomic structure of the binary icosahedral (i) ScZn7.33quasicrystal has been investigated by means of high-resolution synchrotron single-crystal X-ray diffraction and absolute scale measurements of diffuse scattering. The average atomic structure has been solved using the measured Bragg intensity data based on a six-dimensional model that is isostructural to the i-YbCd5.7one. The structure is described with a quasiperiodic packing of large Tsai-type rhombic triacontahedron clusters and double Friauf polyhedra (DFP), both resulting from a close-packing of a large (Sc) and a small (Zn) atom. The difference in chemical composition between i-ScZn7.33and i-YbCd5.7was found to lie in the icosahedron shell and the DFP where in i-ScZn7.33chemical disorder occurs on the large atom sites, which induces a significant distortion to the structure units. The intensity in reciprocal space displays a substantial amount of diffuse scattering with anisotropic distribution, located around the strong Bragg peaks, that can be fully interpreted as resulting from phason fluctuations, with a ratio of the phason elastic constantsK2/K1= −0.53,i.e.close to a threefold instability limit. This induces a relatively large perpendicular (or phason) Debye–Waller factor, which explains the vanishing of `high-Qperp' reflections.

Absorption Coefficients of Inelastic Dynamic X-Ray Diffraction

2014 ◽  
pp. 483-502
Keyword(s):  
Absorption Coefficient ◽  
Inelastic Scattering ◽  
Waller Factor ◽  
Time Dependent ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Charge Current ◽  
Dispersion Equations ◽  
Debye Waller Factor

The X-ray inelastic scattering phenomena during the time-dependent perturbations are described with the aid of dynamical dispersion equations coupled with charge current in the Maxwell equations towards the appearance of the Debye-Waller factor driving the absorption coefficient, either for inelastic thermal diffusion and the Compton scattering, respectively.

Study on Effects of Heavy Ion Irradiation on CeO2 by Using Synchrotron Radiation X-Ray Absorption Spectroscopy -as a Simulation Study for Radiation Damage in High-Burnup Light Water Reactor Fuels-

2007 ◽  
Vol 1043 ◽  
Author(s):  
Hirotaka Ohno ◽  
Daiju Matsumura ◽  
Yasuo Nishihata ◽  
Jun'ichiro Mizuki ◽  
Norito Ishikawa ◽  
...  
Keyword(s):  
Thin Films ◽  
Synchrotron Radiation ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Waller Factor ◽  
X Ray ◽  
Debye Waller Factor ◽  
Atomic Distance ◽  
Exafs Measurement ◽  
X Ray Absorption

AbstractCeO2 thin films were irradiated with 200MeV Xe ions. Effects of the irradiation were studied by using Extended X-ray Absorption Fine Structure (EXAFS) measurement at SPring8 synchrotron radiation facility. EXAFS spectra for the irradiated thin films near the Ce K-edge show that the coordination number for oxygen atoms around Ce atom decreases and that the Ce-O Debye-Waller factor increases by the irradiation. The atomic distance between oxygen atom and Ce atom does not vary within the accuracy of EXAFS measurement. The effect of high density electronic excitation on the structure of CeO2 is discussed.

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