Energy determination of synchrotron X-ray beam energy in the high energy region of 38–50keV using powder diffraction patterns of the standard powder Si640b

2010 ◽  
Vol 619 (1-3) ◽  
pp. 147-149 ◽  
Author(s):  
Nicholas A. Rae ◽  
M. Tauhidul Islam ◽  
Christopher T. Chantler ◽  
Martin D. de Jonge
Keyword(s):  
Powder Diffraction ◽  
Energy Region ◽  
Beam Energy ◽  
High Energy ◽  
High Energy Region ◽  
X Ray ◽  
Standard Powder ◽  
Diffraction Patterns ◽  
Energy Determination

An empirical derivation of the X-ray optic transmission profile used in calibrating the Planetary Instrument for X-ray Lithochemistry (PIXL) for Mars 2020

2018 ◽  
Vol 33 (2) ◽  
pp. 162-165 ◽  
Author(s):  
C. M. Heirwegh ◽  
W. T. Elam ◽  
D. T. Flannery ◽  
A. C. Allwood
Keyword(s):  
Energy Region ◽  
High Energy ◽  
Conventional Approach ◽  
Smoothing Algorithm ◽  
Correction Factors ◽  
High Energy Region ◽  
X Ray ◽  
Straightforward Method ◽  
Specific Correction ◽  
Energy Portion

Calibration of the prototype Planetary Instrument for X-ray Lithochemistry (PIXL) selected for Mars 2020 has commenced with an empirical derivation of the X-ray optic transmission profile. Through a straightforward method of dividing a measured “blank” spectrum over one calculated assuming no optic influence, a rudimentary profile was formed. A simple boxcar-smoothing algorithm was implemented to approximate the complete profile that was incorporated into PIQUANT. Use of this form of smoothing differs from the more conventional approach of using a parameter-based function to complete the profile. Comparison of element-specific correction factors, taken from a measurement of NIST SRM 610, was used to assess the accuracy of the new profile. Improvement in the low- to mid-energy portion of the data was apparent though the high-energy region diverged from unity, and thus, requires further refinement.

An X-ray investigation of synthetic pyroxenes in the system acmite--diopside-water at 1000 kg/cm2 watervapour pressure

1963 ◽  
Vol 33 (263) ◽  
pp. 625-634 ◽  
Author(s):  
J. Nolan ◽  
A. D. Edgar
Keyword(s):  
Least Squares ◽  
Linear Relationship ◽  
Water Vapour ◽  
Powder Diffraction ◽  
Vapour Pressure ◽  
Water Vapour Pressure ◽  
Ray Method ◽  
X Ray ◽  
Diffraction Patterns

SummaryAn X-ray investigation has been made of synthetic pyroxenes in the system acmite-diopside, crystallized at 750° C and 1000 kg/cm2 water-vapour pressure. Lattice parameters of these pyroxenes have been determined by least squares analyses of powder diffraction patterns and show an approximately linear relationship with composition, plotted as weight per cent. A rapid X-ray method has also been devised for the determination of the compositions of pyroxenes of this series.

J. D. Hanawalt Powder Diffraction Award Lecture

1983 ◽  
Vol 27 ◽  
pp. 3-18
Author(s):  
L. K. Frevel
Keyword(s):  
Powder Diffraction ◽  
Computer Search ◽  
Fingerprint Matching ◽  
X Ray ◽  
Future Developments ◽  
The Past ◽  
Standard Powder ◽  
Diffraction Patterns ◽  
Machine Readable

AbstractA condensed chronology of computer SEARCH/MATCH programs for the analysis of multiphase crystalline powders is presented covering the years 1965 to 1981. For this period the various algorithms for searching a data base of standard powder diffraction patterns, {ds, (I/I1)s}, are predicated on empirical “fingerprint” matching of the experimental powder data, {dν,Iν}, with one or more of the standard patterns. Within the past year an interactive computer SEARCH/MATCH program has been developed based on a structure-sensitive SEARCH procedure.The evolution of computer SEARCH/MATCH procedures undoubtedly will continue and will be influenced by marked improvements in the quality of digitized, machine-readable, powder diffraction data. Three conjectures are offered on future developments in x-ray diffractometry.

Indexing of Powder Diffraction Patterns

1962 ◽  
Vol 6 ◽  
pp. 1-17 ◽  
Author(s):  
P. M. de Wolff
Keyword(s):  
Powder Diffraction ◽  
Initial Phase ◽  
Complete Solution ◽  
Powder Pattern ◽  
X Ray ◽  
Physical Limit ◽  
Unit Cells ◽  
Diffraction Patterns ◽  
Influence Of Impurities

AbstractDespite the advances of the electron mtcrodiflraction technique, the determination of unit cells of microcrystalline compounds still depends in many cases on the interpretation of the X-ray powder pattern. The feasibility of this interpretation depends strongly un the precision of the data, the present-day level of which is far from its physical limit. It could be improved by application of monochromators in diflractometry. Some possible methods are discussed. With regard to interpretation, a survey of existing methods is given (Lipson, Ito, de Wolff, Szoldos). Some of these techniques are suitable for computers, at least in the initial phase of the procedure. This is illustrated by application of a zone-finding program for the complete solution of a given pattern. Finally, the influence of impurities and other disturbing factors is discussed.

XAFS in the high-energy region

1998 ◽  
Vol 5 (3) ◽  
pp. 1007-1009 ◽  
Author(s):  
Y. Nishihata ◽  
O. Kamishima ◽  
Y. Kubozono ◽  
H. Maeda ◽  
S. Emura
Keyword(s):  
Fine Structure ◽  
Energy Region ◽  
High Energy ◽  
High Energy Region ◽  
Core Hole ◽  
X Ray ◽  
The Core ◽  
Absorption Fine ◽  
X Ray Absorption ◽  
Absorption Edges

XAFS (X-ray absorption fine-structure) spectra were measured near K-absorption edges of Ce (40.5 keV), Dy (53.8 keV), Ta (67.4 keV) and Pt (78.4 keV). The blunt K-edge jump due to the finite lifetime of the core hole was observed. This makes it difficult to extract EXAFS (extended X-ray absorption fine-structure) functions at low k values. Local structure parameters can be evaluated from the EXAFS spectra above K-absorption edges in the high-energy region as well as from those above L III-edges. It was found that the finite-lifetime effect of the core hole is effectively taken into the photoelectron mean-free-path term, as predicted theoretically.

scholarly journals Conformational properties of N',N'-dimethylamides of N-acetyldehydroalanine and N-acetyl-(Z)-dehydrophenylalanine.

2001 ◽  
Vol 48 (4) ◽  
pp. 1179-1183 ◽  
Author(s):  
D Siodłak ◽  
M A Broda ◽  
B Rzeszotarska ◽  
A E Kozioł ◽  
I Dybała
Keyword(s):  
Energy Region ◽  
High Energy ◽  
High Energy Region ◽  
Energy Calculations ◽  
X Ray ◽  
Ramachandran Map ◽  
Conformational Preferences ◽  
Conformational Properties

Conformational preferences of Ac-deltaAla-NMe2 and Ac-(Z)-deltaPhe-NMe2 were studied and compared with those of their monomethyl counterparts as well as with those of their saturated analogues. X-Ray data and energy calculations revealed a highly conservative conformation of the dehydro dimethylamides, which is located in a high-energy region of the Ramachandran map.

scholarly journals Analysis of Shielding Performance of Radiation-Shielding Materials According to Particle Size and Clustering Effects

2021 ◽  
Vol 11 (9) ◽  
pp. 4010
Author(s):  
Seon-Chil Kim
Keyword(s):  
Particle Size ◽  
Polymer Material ◽  
Energy Region ◽  
High Energy ◽  
Radiation Shielding ◽  
High Energy Region ◽  
Particle Structure ◽  
Effect Of Particle Size ◽  
Extensive Body ◽  
Shielding Material

In the field of medical radiation shielding, there is an extensive body of research on process technologies for ecofriendly shielding materials that could replace lead. In particular, the particle size and arrangement of the shielding material when blended with a polymer material affect shielding performance. In this study, we observed how the particle size of the shielding material affects shielding performance. Performance and particle structure were observed for every shielding sheet, which were fabricated by mixing microparticles and nanoparticles with a polymer material using the same process. We observed that the smaller the particle size was, the higher both the clustering and shielding effects in the high-energy region. Thus, shielding performance can be improved. In the low-dose region, the effect of particle size on shielding performance was insignificant. Moreover, the shielding sheet in which nanoparticles and microsized particles were mixed showed similar performance to that of the shielding sheet containing only microsized particles. Findings indicate that, when fabricating a shielding sheet using a polymer material, the smaller the particles in the high-energy region are, the better the shielding performance is. However, in the low-energy region, the effect of the particles is insignificant.

Sign in / Sign up

Export Citation Format

Share Document