scholarly journals Study of the collection solid angle of doubly curved crystals

2020 ◽  
Vol 19 (04) ◽  
Keyword(s):  
Solid Angle ◽  
Doubly Curved ◽  
Doubly Curved Crystals

Source misalignment effects on crystal collection solid angle and intensity profile

2012 ◽  
Vol 45 (5) ◽  
pp. 890-901 ◽  
Author(s):  
Sayyed Jalal Pestehe ◽  
Golamreza Askari Germi
Keyword(s):  
Crystal Surface ◽  
Solid Angle ◽  
Intensity Profile ◽  
Bragg Angle ◽  
Angular Deviation ◽  
X Ray ◽  
Trial And Error Method ◽  
General Relations ◽  
Doubly Curved ◽  
Doubly Curved Crystals

The X-ray optics of singly and doubly curved crystals are studied using a vector procedure and rotation matrices and general relations for the angular deviation from the Bragg angle over the crystal surface with a source aligned or misaligned on the Rowland circle. Hence, the effective scattering area, collection solid angle and diffracted X-ray intensity profile on the crystal surface are derived. The effective areas and the diffracted X-ray intensity profiles on the crystal surface for both aligned and misaligned source cases are plotted and compared. It is argued that the introduced point-focusing crystal configuration confirms the radii that have been obtained previously by a trial and error method by optimizing the crystal collection solid angle.

X‐ray focusing optics. I. Applications of wave optics to doubly curved crystals with a point x‐ray source

1995 ◽  
Vol 77 (5) ◽  
pp. 1843-1848 ◽  
Author(s):  
F. N. Chukhovskii ◽  
W. Z. Chang ◽  
E. Förster
Keyword(s):  
Wave Optics ◽  
X Ray ◽  
Doubly Curved ◽  
Doubly Curved Crystals

C-11 Invited—Low-Power Monochromatic Focused Beam XRF Systems Using Doubly Curved Crystals

2007 ◽  
Vol 22 (2) ◽  
pp. 188-188
Author(s):  
Z. W. Chen ◽  
F. Wei ◽  
B. Beumer ◽  
D. Li ◽  
W. M. Gibson
Keyword(s):  
Low Power ◽  
Doubly Curved ◽  
Doubly Curved Crystals ◽  
Focused Beam

Optimizing conditions for x-ray microchemical analysis in analytical electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 548-549 ◽  
Author(s):  
N. J. Zaluzec
Keyword(s):  
Solid Angle ◽  
Analytical Electron Microscopy ◽  
Incident Beam ◽  
Thin Foil ◽  
Experimental Conditions ◽  
X Ray ◽  
Microchemical Analysis ◽  
Analytical Electron ◽  
Image Position ◽  
Incident Beam Energy

The ultimate sensitivity of microchemical analysis using x-ray emission rests in selecting those experimental conditions which will maximize the measured peak-to-background (P/B) ratio. This paper presents the results of calculations aimed at determining the influence of incident beam energy, detector/specimen geometry and specimen composition on the P/B ratio for ideally thin samples (i.e., the effects of scattering and absorption are considered negligible). As such it is assumed that the complications resulting from system peaks, bremsstrahlung fluorescence, electron tails and specimen contamination have been eliminated and that one needs only to consider the physics of the generation/emission process.The number of characteristic x-ray photons (Ip) emitted from a thin foil of thickness dt into the solid angle dΩ is given by the well-known equation

Contrast in Scanning Images of Thin Crystals

1972 ◽  
Vol 30 ◽  
pp. 520-521
Author(s):  
S. Kimoto ◽  
H. Hashimoto ◽  
S. Takashima ◽  
R. M. Stern ◽  
T. Ichinokawa
Keyword(s):  
Crystal Surface ◽  
Solid Angle ◽  
Incident Angle ◽  
Intensity Variation ◽  
Lattice Defects ◽  
Scanning Microscope ◽  
Electron Detector ◽  
Backscattered Electrons ◽  
Electron Image ◽  
Backscattered Electron

The most well known application of the scanning microscope to the crystals is known as Coates pattern. The contrast of this image depends on the variation of the incident angle of the beam to the crystal surface. The defect in the crystal surface causes to make contrast in normal scanning image with constant incident angle. The intensity variation of the backscattered electrons in the scanning microscopy was calculated for the defect in the crystals by Clarke and Howie. Clarke also observed the defect using a scanning microscope.This paper reports the observation of lattice defects appears in thin crystals through backscattered, secondary and transmitted electron image. As a backscattered electron detector, a p-n junction detector of 0.9 π solid angle has been prepared for JSM-50A. The gain of the detector itself is 1.2 x 104 at 50 kV and the gain of additional AC amplifier using band width 100 Hz ∼ 10 kHz is 106.

High spatial resolution x-ray microanalysis of interfaces

1995 ◽  
Vol 53 ◽  
pp. 284-285
Author(s):  
J. R. Michael
Keyword(s):  
Spatial Resolution ◽  
Electron Probe ◽  
Solid Angle ◽  
Collection Efficiency ◽  
Spatial Scales ◽  
Energy Dispersive Spectrometer ◽  
X Rays ◽  
X Ray ◽  
Probe Size ◽  
Brightness Field

X-ray microanalysis in the analytical electron microscope (AEM) refers to a technique by which chemical composition can be determined on spatial scales of less than 10 nm. There are many factors that influence the quality of x-ray microanalysis. The minimum probe size with sufficient current for microanalysis that can be generated determines the ultimate spatial resolution of each individual microanalysis. However, it is also necessary to collect efficiently the x-rays generated. Modern high brightness field emission gun equipped AEMs can now generate probes that are less than 1 nm in diameter with high probe currents. Improving the x-ray collection solid angle of the solid state energy dispersive spectrometer (EDS) results in more efficient collection of x-ray generated by the interaction of the electron probe with the specimen, thus reducing the minimum detectability limit. The combination of decreased interaction volume due to smaller electron probe size and the increased collection efficiency due to larger solid angle of x-ray collection should enhance our ability to study interfacial segregation.

Sign in / Sign up

Export Citation Format

Share Document