On the dilatation of synthetic type Ib diamond by substitutional nitrogen impurity

1991 ◽  
Vol 337 (1648) ◽  
pp. 497-520 ◽  
Keyword(s):  
Infrared Absorption ◽  
Infrared Absorption Spectrum ◽  
Internal Standard ◽  
Optical Microscope ◽  
Lattice Parameter ◽  
Bragg Angle ◽  
Growth Sector ◽  
Double Crystal ◽  
X Ray ◽  
Nitrogen Impurity

Sequences of high Bragg-angle (0 B = 74°) double-crystal X-ray topographs taken at the SRS (Daresbury, U.K.) have yielded precise measurements of lattice parameter differences between growth sectors of different crystallographic forms in a large undoped synthetic diamond whose type Ib infrared absorption spectrum (principal peak at 1130 cm -1 ) indicated atomically dispersed nitrogen, singly substituting for carbon, as the only detectable impurity. The plate-shaped specimen, polished parallel to (110), 5.0 x 3.2 mm 2 in area, 0.7 mm thick, possessed an unusually well developed (110) growth sector containing nitrogen impurity concentration of only ca. 10 -6 , which served as an internal standard of pure-diamond lattice parameter with which lattice parameters of nitrogen-containing growth sectors were compared. The specimen’s suitability for precision diffractometry was checked by comprehensive tests using optical microscope techniques, cathodoluminescence and single-crystal X-ray topography. The double-crystal combination was silicon reference crystal, asymmetric 175 reflection, with diamond specimen symmetrical 440 reflection. The principal measurement was the increase of the lattice parameter, a 0 , of the (111) growth sector (nitrogen content 88 + 7 parts per 10 6 atomic) relative to that of the (110) sector: Aa 0 / a 0 = 1.18 + 0.07 x 10 -5 . In terms of measured infrared absorption coefficient at 1130 cm -1 , this gives Aa 0/a 0 = (2.95 + 0.27) x 10 -6 [p(1130 cm -1 )/cm -1 ], which is believed to hold for growth sectors of all crystallographic forms. Combination with the nitrogen assay findings of Woods, van Wyk & Collins ( Phil. Mag. B 62. 589-595 (1990)) provides a direct relation to c N , the fractional atomic concentration of substitutional nitrogen, as A a 0 / a 0 = (0.14 + 0.02) c N , which indicates that the effective volume of a single substitutional nitrogen atom in diamond is 1.41 +0.06 times that of the carbon atom it replaces. This substantial dilatation conflicts with several models for the substitutional nitrogen structure.

X-Ray Spectrographic Analysis of the 3-d Transition Metal Corrosion Products Using Potassium Bromide Disks*

1963 ◽  
Vol 7 ◽  
pp. 590-597
Author(s):  
L. A. Schluter
Keyword(s):  
Pulse Height ◽  
Weight Ratio ◽  
Internal Standard ◽  
Corrosion Products ◽  
Metal Corrosion ◽  
Small Samples ◽  
Bragg Angle ◽  
X Ray ◽  
Calibration Curves ◽  
Intensity Ratios

AbstractA technique has been developed for quantitative analysis of the major constituents in small samples (less than 0.1 g) of corrosion products found On various missile parts. The technique was developed primarily to aid in interpretation of X-ray diffraction patterns of multicomponent corrosion products. The corrosion sample is mixed with KBr and the mixture is pressed into a disk in the same fashion commonly used in infrared work. The Br Kβ1 line serves as an internal standard. Intensities of the element's Kα line and the internal standard are established by scanning through the appropriate Bragg angle and recording peak heights on a strip-chart recorder. A xenon-filled proportional detector and a pulse-height analyzer were used.The percent of an element is determined by references to calibration curves which relate intensity ratios to weight ratios for the 3-d transition metals. The oxides of the metals were used in the preparation of the calibration curves. The weight ratio vs. intensity ratio relationship is linear over the weight ratio range 0.01 to 0.11. Data were collected using an air path and a helium path; the higher intensity ratios obtained with, the helium path, and the dependence of intensity on atomic number are illustrated. A comparison is made between the intensity ratios in a KBr matrix and in a NaBr matrix. The technique developed requires about 15 min sample preparation time.

scholarly journals Performance of nearly fixed offset asymmetric channel-cut crystals for X-ray monochromators

2019 ◽  
Vol 26 (6) ◽  
pp. 1879-1886
Author(s):  
Ronald Frahm ◽  
Qianshun Diao ◽  
Vadim Murzin ◽  
Benjamin Bornmann ◽  
Dirk Lützenkirchen-Hecht ◽  
...  
Keyword(s):  
Energy Range ◽  
Photon Energy ◽  
Exafs Spectrum ◽  
Symmetric Case ◽  
Bragg Angle ◽  
Performance Tests ◽  
Asymmetric Channel ◽  
Double Crystal ◽  
X Ray ◽  
Exit Beam

X-ray double-crystal monochromators face a shift of the exit beam when the Bragg angle and thus the transmitted photon energy changes. This can be compensated for by moving one or both crystals accordingly. In the case of monolithic channel-cut crystals, which exhibit utmost stability, the shift of the monochromated beam is inevitable. Here we report performance tests of novel, asymmetrically cut, channel-cut crystals which reduce the beam movements by more than a factor of 20 relative to the symmetric case over the typical energy range of an EXAFS spectrum at the Cu K-edge. In addition, the presented formulas for the beam offset including the asymmetry angle directly indicate the importance of this value, which has been commonly neglected so far in the operation of double-crystal monochromators.

A new method for measuring the crystallinity index of quartz by infrared spectroscopy

1991 ◽  
Vol 55 (381) ◽  
pp. 579-582 ◽  
Author(s):  
S. Shoval ◽  
Y. Ginott ◽  
Y. Nathan
Keyword(s):  
Absorption Spectrum ◽  
Infrared Spectroscopy ◽  
Infrared Absorption ◽  
Infrared Absorption Spectrum ◽  
Crystallinity Index ◽  
New Method ◽  
X Ray ◽  
First Derivative

AbstractA new method for measuring the crystallinity index of quartz is presented. It is based on the measurement of the intensity of the first derivative of the infrared absorption spectrum at the shoulder at c. 1145 cm−1. The results correlate well with X-ray and D.T.A. crystallinity measurements.

X-Ray Double Crystal Diffractometer Investigations of Implanted Silicon: D+And N+

1971 ◽  
Vol 15 ◽  
pp. 504-515 ◽  
Author(s):  
E. H. teKaat ◽  
G. H. Schwuttke
Keyword(s):  
Radiation Damage ◽  
Lattice Parameter ◽  
Double Peak ◽  
Double Crystal ◽  
X Ray ◽  
Projected Range ◽  
Insight Into ◽  
Double Crystal Diffractometer

Double crystal diffractometer measurements on silicon bombarded to a fluence >1016ions/cm2with 1 MeV deuterium and 2 MeV nitrogen are reported. Such measurements provide insight into radiation damage in silicon through the observation of Bragg case pendelloesung fringes and double peak rocking curves. Bragg case pendelloesung fringes are used to determine nondestructively the projected range of ions in silicon. Double peak rocking curves are used to measure changes in lattice parameter with the ion dose. Finally, a model of radiation damage in silicon is presented.

Angular Corrections for the Seemann-Bohlin X-Ray Diffractometer

1991 ◽  
Vol 6 (4) ◽  
pp. 200-203 ◽  
Author(s):  
D. Rafaja ◽  
V. Valvoda
Keyword(s):  
Internal Standard ◽  
Correction Method ◽  
Lattice Parameter ◽  
Peak Position ◽  
Precise Determination ◽  
Thin Layers ◽  
X Ray ◽  
Diffraction Peaks ◽  
Steel Substrates

AbstractA method for the correction of peak position for the Seemann-Bohlin X-ray diffractometer, useful for practical application, is presented. The position of diffraction peaks is largely influenced by both the displacement of specimen from the diffractometer circle and the shift of the X-ray tube focus. The described correction method has been used for investigation of thin layers, especially for the precise determination of both lattice parameter and stresses in thin films. The application of the method is illustrated on samples of TiN and ZrN coatings deposited on steel substrates and additionally covered with a thin film of Si or Ta or TaC powder used as an internal standard.

Certification of standard reference material 1878b respirable α-quartz

2016 ◽  
Vol 31 (3) ◽  
pp. 211-215 ◽  
Author(s):  
David R. Black ◽  
Marcus H. Mendenhall ◽  
Pamela S. Whitfield ◽  
Donald Windover ◽  
Albert Henins ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Occupational Safety ◽  
Internal Standard ◽  
Lattice Parameter ◽  
Standard Reference Materials ◽  
Quartz Powder ◽  
Phase Purity ◽  
X Ray ◽  
Safety And Health ◽  
Quantitative Analyses

The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to address specific aspects of the performance of X-ray powder diffraction instruments. This report describes SRM 1878b, the third generation of this powder diffraction SRM. SRM 1878b is intended for use in the preparation of calibration standards for the quantitative analyses of α-quartz by X-ray powder diffraction in accordance to National Institute for Occupational Safety and Health Analytical Method 7500, or equivalent. A unit of SRM 1878b consists of approximately 5 g of α-quartz powder bottled in an argon atmosphere. It is certified with respect to crystalline phase purity, or amorphous phase content, and lattice parameter. Neutron powder diffraction, both time of flight and constant wavelength, was used to certify the phase purity using SRM 676a as an internal standard. A NIST-built diffractometer, incorporating many advanced design features was used for certification measurements for lattice parameters.

Design and feasibility of quick EXAFS scans for a `broomstick' double-crystal monochromator at PLS beamline

1998 ◽  
Vol 5 (3) ◽  
pp. 524-526 ◽  
Author(s):  
J. M. Lee ◽  
Nark-Eon Sung ◽  
Jeong-Kweon Park ◽  
Jah-Geol Yoon ◽  
Jin-Hong Kim ◽  
...  
Keyword(s):  
Fine Structure ◽  
Step Motor ◽  
Bragg Angle ◽  
Scan Design ◽  
Double Crystal ◽  
X Ray ◽  
Absorption Fine ◽  
Double Crystal Monochromator ◽  
Continuous Rotation ◽  
X Ray Absorption

A data-collection technique for quick extended X-ray absorption fine-structure spectroscopy (QEXAFS) was developed with a new `broomstick' double-crystal monochromator, which has been installed for X-ray absorption fine-structure (XAFS) applications at the Pohang Light Source. The monochromator operates in a fixed-exit scan mode as the Bragg angle is varied from 8 to 80°, corresponding to 2–14 keV, using an Si(111) crystal. The monochromator scan capability was investigated by analysing EXAFS data quality from step-scan and from continuous rotation of the Bragg crystal reflection angle. In our fast continuous-scan design, the electronic pulsing speed of the step motor is adjustable to avoid the monochromatic beam instability caused by serious mechanical resonance. The feasibility of QEXAFS scanning is demonstrated by a typical EXAFS scan (e.g. 1 keV range) being taken within 1 min.

Investigation of the Homogeneity and Defect Structure in Semi-Insulating Lec GaAs Single Crystals by Synchrotron Radiation Double Crystal X-Ray Topography.

1984 ◽  
Vol 41 ◽  
Author(s):  
S J Barnett ◽  
B K Tanner ◽  
G. T. Brown
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystals ◽  
Defect Structure ◽  
Deep Level ◽  
Lattice Parameter ◽  
Double Crystal ◽  
X Ray ◽  
Lec Gaas ◽  
Order Of Magnitude ◽  
Small Lattice

AbstractThe high intensity and large beam size of a synchrotron radiation source have been exploited in order to obtain double crystal X-ray topographs of whole 2in. and 3in. slices of semi-insulating LEC GaAs single crystals. Exposure times, typically 30 minutes for high resolution topographs, are at least one order of magnitude down on those required when using a conventional source. Variations in relative lattice parameter and lattice tilt have been measured as a function of position on the slice. The defect structure has been imaged and dislocations are seen in cellular configurations, slip bands and linear arrays (lineage), the latter of which are shown to be associated with small lattice tilts, typically 30”. The defect structure revealed on the topographs has been correlated with 1μm infrared absorption micrographs which are believed to represent the concentration of the dominant deep level EL2.

Investigation of the lattice tilts at growth sector boundaries using double-crystal X-ray diffractometry

1986 ◽  
Vol 53 (3) ◽  
pp. 377-383 ◽  
Author(s):  
D. Y. Parpia ◽  
S. J. Barnett ◽  
M. J. Hill
Keyword(s):  
Growth Sector ◽  
Double Crystal ◽  
X Ray
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