Reconstruction of the wave tilt and orientation of tilt axis using OVI

2007 ◽  
Author(s):  
M. Borwińska ◽  
A. Popiołek-Masajada ◽  
B. Dubik
Keyword(s):  
Tilt Axis ◽  
Wave Tilt

Improvements in the electron probe forming capabilities and x-ray hole counts in the Philips TEM

1983 ◽  
Vol 41 ◽  
pp. 376-377
Author(s):  
Richard L. McConville
Keyword(s):  
Field Strength ◽  
Electron Probe ◽  
Spherical Aberration ◽  
Focal Length ◽  
Objective Lens ◽  
Parallel Beam ◽  
Tilt Axis ◽  
X Ray ◽  
Small Probe ◽  
Specimen Height

A second generation twin lens has been developed. This symmetrical lens with a wider bore, yet superior values of chromatic and spherical aberration for a given focal length, retains both eucentric ± 60° tilt movement and 20°x ray detector take-off angle at 90° to the tilt axis. Adjust able tilt axis height, as well as specimen height, now ensures almost invariant objective lens strengths for both TEM (parallel beam conditions) and STEM or nano probe (focused small probe) modes.These modes are selected through use of an auxiliary lens situ ated above the objective. When this lens is on the specimen is illuminated with a parallel beam of electrons, and when it is off the specimen is illuminated with a focused probe of dimensions governed by the excitation of the condenser 1 lens. Thus TEM/STEM operation is controlled by a lens which is independent of the objective lens field strength.

Defocus ramp correction in spot-scan imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 130-131
Author(s):  
Kenneth H. Downing
Keyword(s):  
Computer Control ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Objective Lens ◽  
Electron Crystallography ◽  
Contrast Transfer Function ◽  
Tilt Axis ◽  
Specimen Height ◽  
The Difference ◽  
Envelope Functions

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.

Wave-tilt measurements of ground properties

1965 ◽  
Vol 1 (4) ◽  
pp. 106 ◽  
Author(s):  
P.J.D. Gething ◽  
A.D. Morgan ◽  
E.G. Shepherd ◽  
D.V. Tibble
Keyword(s):  
Wave Tilt

scholarly journals Ultraprecision grinding of small-aperture concave aspheric mould insert with tilt axis method

Procedia CIRP ◽  
2018 ◽  
Vol 71 ◽  
pp. 505-510 ◽  
Author(s):  
Guangpeng Yan ◽  
Kaiyuan You ◽  
Fengzhou Fang
Keyword(s):  
Mould Insert ◽  
Small Aperture ◽  
Tilt Axis

Wave tilt sounding of multilayered structures

Radio Science ◽  
1979 ◽  
Vol 14 (6) ◽  
pp. 1069-1076 ◽  
Author(s):  
L. Warne ◽  
D. L. Jaggard ◽  
C. Elachi
Keyword(s):  
Multilayered Structures ◽  
Wave Tilt

scholarly journals On Measuring Section Thickness

2001 ◽  
Vol 9 (4) ◽  
pp. 17-17
Author(s):  
Ron Doole
Keyword(s):  
Film Thickness ◽  
Cross Section ◽  
Accurate Result ◽  
The Other ◽  
Section Thickness ◽  
Plan View ◽  
Tilt Axis ◽  
Measuring Section ◽  
Easy Case

Section thickness can be measured by placing beads of some kind on the top and bottom surfaces of the section. This is then a simple parallax problem.Imagine the specimen in cross section. If there are two particles, one vertically above the other they are separated by the film thickness T. Tilt the film through an angle A and in plan view the particles will separate by a distance D. This can also be extended to account for two particles not vertically above each other but I'll stick to the easy case for the explanation.Take two negatives one at zero tilt and one at tilt of A and measure the separation D. The thickness can be calculated by T=D/sinA.The direction of the tilt axis must be known for the measurements and it is easy to see that the larger the tiit angle and the more accurately the separation is measured, the more accurate the measurement will be. Tilt at both positive and negative angles to get a more accurate result.

Detection of near-water ducts by the wave tilt probing method

Radio Science ◽  
1989 ◽  
Vol 24 (4) ◽  
pp. 499-509
Author(s):  
D. P. Chrissoulidis ◽  
E. E. Kriezis
Keyword(s):  
Wave Tilt

Study of Dynamic Embrittlement in Alloy Bicrystals

1996 ◽  
Vol 458 ◽  
Author(s):  
R. G. Muthiah ◽  
J. A. Pfaendtner ◽  
C. J. McMahon ◽  
P. Lejcek ◽  
V. Paidar
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Crack Growth Rate ◽  
Grain Boundary ◽  
Crack Growth ◽  
Tilt Axis ◽  
Tilt Boundaries ◽  
Symmetrical Tilt ◽  
Dynamic Embrittlement ◽  
Crack Growth Rates

ABSTRACTIn a kinetic model [1] for the phenomenon of dynamic embrittlement, the cracking rate is predicted to be proportional to the diffusivity of the embrittling species along the grain boundary. To test this model, bicrystals of Cu-Sn and Fe-Si with Σ5 symmetrical tilt boundaries are used in which tin and sulfur, respectively, are the embrittling elements. The diffusivities parallel and perpendicular to the tilt axis are expected to be different, therefore the crack growth rates in these two directions should vary in the same ratio as the diffusivities.Preliminary measurements of crack growth rate along the [100] direction in the Cu-Sn alloy bicrystal are presented. The cracking occurred by decohesion along the grain boundary with almost no observable plasticity. The steady state crack growth was found to be approximately 10∼6 m/sec.

Tuned Tilt of Epitaxial Crystals

MRS Bulletin ◽  
1991 ◽  
Vol 16 (6) ◽  
pp. 30-33 ◽  
Author(s):  
C.P. Flynn
Keyword(s):  
Tilt Angle ◽  
First Principles ◽  
Growth Process ◽  
Molecular Beam ◽  
Interfacial Structure ◽  
Tilt Axis ◽  
Atomic Spacing ◽  
The Difference ◽  
Lattice Planes ◽  
Lattice Solid

At first sight it may seem self-evident that epitaxial crystals must grow with their atomic planes parallel to the lattice planes of the substrate crystal. The simplified sketch in Figure 1a shows atoms raining onto a substrate from a molecular beam, and then diffusing to step-edges in a desirably controlled growth process termed step-edge (or ledge) flow. Drawn this way, the conclusion that the planes must lie parallel seems obvious. If, however, the process is heteroepitaxial, and the new lattice (solid circles) differs in spacing or structure from the substrate template (lines), the outcome is less straight-forward. Accommodating the difference of step heights at the interface then requires local tilts amounting to a fraction of one atomic spacing in, say, 25 atoms or perhaps half a degree, depending from one point to the next on details of the neighboring interfacial structure.In what follows I describe a qualitatively different and newly discovered behavior we term coherent tilt. The coherent tilt process causes the atomic planes of the epilayer to grow at an accurately predictable and reproducible angle with respect to the substrate planes. The tilt axis, tilt angle, and sense of rotation remain precisely fixed over an entire substrate, with the result that the process occurs coherently over the dimensions of a macroscopic sample. Large tilts over 7° have already been produced with the angle predictable from first principles to 0.1° The characteristics of coherent tilt are sketched in Figure 1b.

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