Certification of NIST Standard Reference Material 640d

2010 ◽  
Vol 25 (2) ◽  
pp. 187-190 ◽  
Author(s):  
David R. Black ◽  
Donald Windover ◽  
Albert Henins ◽  
David Gil ◽  
James Filliben ◽  
...  
Keyword(s):  
Size Range ◽  
Silicon Powder ◽  
Systematic Errors ◽  
Lattice Parameter ◽  
Standard Reference Materials ◽  
Type B ◽  
Fifth Generation ◽  
Certified Value ◽  
Nist Standard Reference Material ◽  
Produce Strain

The National Institute of Standards and Technology (NIST) certifies a variety of standard reference materials (SRM) to address specific aspects of instrument performance for divergent beam diffractometers. This paper describes SRM 640d, the fifth generation of this powder diffraction SRM, which is certified with respect to the lattice parameter. It consists of approximately 7.5 g silicon powder specially prepared to produce strain-free particles in a size range between 1 and 10 μm to eliminate size-broadening effects. It is typically used for calibrating powder diffractometers for the line position and line shape. A NIST built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the silicon powder measured at 22.5 °C. Both type A, statistical, and type B, systematic, errors have been assigned to yield a certified value for the lattice parameter of a=0.543 159±0.000 020 nm.

scholarly journals Certification of SRM 640f line position and line shape standard for powder diffraction

2020 ◽  
Vol 35 (3) ◽  
pp. 156-159
Author(s):  
David R. Black ◽  
Marcus H. Mendenhall ◽  
Albert Henins ◽  
James Filliben ◽  
James P. Cline
Keyword(s):  
Powder Diffraction ◽  
Silicon Powder ◽  
Lattice Parameter ◽  
Standard Reference Materials ◽  
Line Broadening ◽  
Line Position ◽  
Profile Function ◽  
Systematic Uncertainties ◽  
Certified Value

The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to be used to evaluate specific aspects of the instrument performance of both X-ray and neutron powder diffractometers. This report describes SRM 640f, the seventh generation of this powder diffraction SRM, which is designed to be used primarily for calibrating powder diffractometers with respect to line position; it also can be used for the determination of the instrument profile function. It is certified with respect to the lattice parameter and consists of approximately 7.5 g of silicon powder prepared to minimize line broadening. A NIST-built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the Si powder. Both statistical and systematic uncertainties have been assigned to yield a certified value for the lattice parameter at 22.5 °C of a = 0.5431144 ± 0.000008 nm.

scholarly journals Certification of Standard Reference Material 660c for powder diffraction

2020 ◽  
Vol 35 (1) ◽  
pp. 17-22 ◽  
Author(s):  
David R. Black ◽  
Marcus H. Mendenhall ◽  
Craig M. Brown ◽  
Albert Henins ◽  
James Filliben ◽  
...  
Keyword(s):  
Powder Diffraction ◽  
Lattice Parameter ◽  
Lanthanum Hexaboride ◽  
Standard Reference Materials ◽  
Fourth Generation ◽  
Systematic Uncertainties ◽  
Precursor Material ◽  
Certified Value ◽  
Crystallographic Defects

The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to evaluate specific aspects of instrument performance of both X-ray and neutron powder diffractometers. This report describes SRM 660c, the fourth generation of this powder diffraction SRM, which is used primarily for calibrating powder diffractometers with respect to line position and line shape for the determination of the instrument profile function (IPF). It is certified with respect to lattice parameter and consists of approximately 6 g of lanthanum hexaboride (LaB6) powder. So that this SRM would be applicable for the neutron diffraction community, the powder was prepared from an isotopically enriched 11B precursor material. The microstructure of the LaB6 powder was engineered specifically to yield a crystallite size above that where size broadening is typically observed and to minimize the crystallographic defects that lead to strain broadening. A NIST-built diffractometer, incorporating many advanced design features, was used to certify the lattice parameter of the LaB6 powder. Both Type A, statistical, and Type B, systematic, uncertainties have been assigned to yield a certified value for the lattice parameter at 22.5 °C of a = 0.415 682 6 ± 0.000 008 nm (95% confidence).

Problems Associated with Kα Doublet in Residual Stress Measurements

1979 ◽  
Vol 23 ◽  
pp. 333-339
Author(s):  
S. K. Gupta ◽  
B. D. Cullity
Keyword(s):  
Residual Stress ◽  
Silicon Powder ◽  
Lattice Parameter ◽  
Diffraction Peak ◽  
Parameter Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Techniques ◽  
The Difference ◽  
Similar Accuracy

Since the measurement of residual stress by X-ray diffraction techniques is dependent on the difference in angle of a diffraction peak maximum when the sample is examined consecutively with its surface at two different angles to the diffracting planes, it is important that these diffraction angles be obtained precisely, preferably with an accuracy of ± 0.01 deg. 2θ. Similar accuracy is desired in precise lattice parameter determination. In such measurements, it is imperative that the diffractometer be well-aligned. It is in the context of diffractometer alignment with the aid of a silicon powder standard free of residual stress that the diffraction peak analysis techniques described here have been developed, preparatory to residual stress determinations.

Precision Lattice Parameter Measurements with Guinier Camera and Counter Diffractometer: Comparison and Reconciliation of Results

1982 ◽  
Vol 26 ◽  
pp. 11-24 ◽  
Author(s):  
Allan Brown
Keyword(s):  
Measurement Errors ◽  
Systematic Errors ◽  
Lattice Parameter ◽  
Precision Measurements ◽  
Compound A ◽  
X Ray ◽  
Random Measurement ◽  
Precise Characterization ◽  
The Difference

Different procedures used in precision measurements of lattice parameters are, strictly, only valid if they can be shown to give results that are mutually reproducible. For this purpose reproducibility is defined in terms of the parameters a. and standard deviations a. obtained for X-ray specimens of one or more reference materials. The requirement is that all systematic errors should be minimized to a level below that of the random measurement errors. Where these have a Gaussian distribution the significance of the difference, Δa°, between two , measurements can then be Let;Led by evaluating . Thus, if K < 2 the difference, Δa°, cannot be distinguished from the effects of random measurement errors. This condition should be met for specimens of the same sample if reproducibility is good. For K ≥ 3 the value of Δa° is then taken to reflect real differences in the crystalline Jattice of two X-ray specimens of a given compound. A basis is thus created for the study of solid solubility and for the precise characterization of crystalline compounds.

Accurate determination and correction of the lattice parameter of LaB6(standard reference material 660) relative to that of Si (640b)

2007 ◽  
Vol 40 (2) ◽  
pp. 232-240 ◽  
Author(s):  
C. T. Chantler ◽  
N. A. Rae ◽  
C. Q. Tran
Keyword(s):  
Reference Material ◽  
Standard Reference Material ◽  
Accurate Determination ◽  
Rietveld Analysis ◽  
Lattice Parameter ◽  
Conventional Analysis ◽  
Peak Broadening ◽  
Peak Asymmetry ◽  
Nist Standard Reference Material ◽  
The Mean

X-ray powder diffraction and synchrotron radiation have been used to determine the lattice parameter of the NIST standard reference material (SRM 660) LaB6as 4.156468 Å with an accuracy of 12 parts per million (p.p.m.), calibrated relative to the lattice parameter of the Si powder standard [a0= 5.430940 (11) Å, Si 640b]. A discrepancy of 0.00048 (5) Å, or nine standard deviations from the NIST reference, is observed between the currently accepted lattice spacing of LaB6and the measured value. Twelve different measurements of the lattice parameter were made at beam energies between 10 and 20 keV. The observed discrepancy in the lattice parameter is consistent for the different energies used. The absolute values of the mean difference between the measured and calculated 2θ centroids, \overline{\left| \delta 2 \theta \right|}, are highly consistent, between 0.0002 and 0.0004° for energies from 5 to 14 keV, and between 0.0005 and 0.0008° for energies from 15 to 20 keV. In order to determine the peak positions with high precision, account must be taken of the observed peak asymmetry. It is shown that significant asymmetry is due to peak broadening and must be taken into account in order to determine accurate peak locations and lattice spacings. The approach shows significant advantages over conventional analysis. The analysis of peak broadening is compared with models used in Rietveld analysis.

An Experimental Examination of Error Functions for Bragg-Brentano Powder Diffractometry

1992 ◽  
Vol 36 ◽  
pp. 663-670 ◽  
Author(s):  
H.W. King ◽  
E.A. Payzant
Keyword(s):  
High Temperature ◽  
Systematic Errors ◽  
Lattice Parameter ◽  
Parameter Determination ◽  
Experimental Examination ◽  
X Ray ◽  
Error Functions ◽  
Computer Methods ◽  
Single Function ◽  
High Temperature Furnaces

AbstractA single function for the elimination of errors in precision lattice parameter determination has not been developed for the Bragg-Brentano x-ray diffractometer method, because of the different angular dependencies of the systematic errors. A review of the error functions shows that all but one can be calculated from the instrumental settings and known properties of a sample under investigation. The residual sample displacement error can be then be eliminated by using extrapolation plots or computer methods to correct the data to cosθcotθ plots. The slopes of cosθcotθ plots can also be used to align high temperature furnaces and low temperature cryostats mounted on x-ray diffractometers.

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.

Ab Initio Study of Pressure Induced Structural, Magnetic and Electronic Properties in Plutonium Pnictides

2014 ◽  
Vol 1047 ◽  
pp. 11-17 ◽  
Author(s):  
Chandrabhan Makode ◽  
Jagdeesh Pataiya ◽  
M. Aynyas ◽  
Sankar P. Sanyal
Keyword(s):  
Bulk Modulus ◽  
Total Energy ◽  
Electronic Properties ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Tight Binding ◽  
Energy Band Diagram ◽  
Lattice Parameter ◽  
Local Spin Density Approximation ◽  
Type B

We have investigated the pressure induced structural and electronic properties of plutonium pnictides (PuY, Y= P, As, Sb). The total energy as a function of volume is obtained by means of self-consistent tight binding linear muffin-in-orbital (TB-LMTO) method within the local spin density approximation (LSDA). From present study with the help of total energy calculations (spin polarized) it is found that PuP, PuAs and PuSb are stable in NaCl – type structure under ambient pressure. The structural stability of PuP, PuAs and PuSb changes under the application of pressure. We predict a structural phase transition from NaCl-type (B1-phase) to CsCl-type (B2-phase) structure for these Pu-pnictides in the pressure range of 20.8 – 42.0 GPa. We also calculate the lattice parameter, bulk modulus, band structure and density of states. From energy band diagram it is observed that all the three compounds exhibit metallic behaviour. The calculated equilibrium lattice parameters and bulk modulus are in good agreement with available experimental data.

Certification of Standard Reference Material 660B

2011 ◽  
Vol 26 (2) ◽  
pp. 155-158 ◽  
Author(s):  
David R. Black ◽  
Donald Windover ◽  
Albert Henins ◽  
James Filliben ◽  
James P. Cline
Keyword(s):  
Unit Cell Parameter ◽  
Cell Parameter ◽  
Unit Cell ◽  
Type B ◽  
Profile Function ◽  
The Third ◽  
Precursor Material ◽  
Certified Value ◽  
Crystallographic Defects

This report describes SRM 660b, the third generation of this powder diffraction SRM used primarily for determination of the instrument profile function (IPF). It is certified with respect to unit-cell parameter. It consists of approximately 6 g LaB6 powder prepared using a 11B isotopically enriched precursor material so as to render the SRM applicable to the neutron diffraction community. The microstructure of the LaB6 powder was engineered to produce a crystallite size above that where size broadening is typically observed and to minimize the crystallographic defects that lead to strain broadening. A NIST -built diffractometer, incorporating many advanced design features, was used to certify the unit-cell parameter of the LaB6 powder. Both type A, statistical, and type B, systematic, errors have been assigned to yield a certified value for the unit-cell parameter of a=0.415691(8) nm at 22.5°C.

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