Correlation analysis of radiation damage

Till now correlation functions have been used in electron microscopy for two purposes: a) to find the common origin of two micrographs representing the same object, b) to check the optical parameters e. g. the focus. There is a third possibility of application, if all optical parameters are constant during a series of exposures. In this case all differences between the micrographs can only be caused by different noise distributions and by modifications of the object induced by radiation.Because of the electron noise, a discrete bright field image can be considered as a stochastic series Pm,where i denotes the number of the image and m (m = 1,.., M) the image element. Assuming a stable object, the expectation value of Pm would be Ηm for all images. The electron noise can be introduced by addition of stationary, mutual independent random variables nm with zero expectation and the variance. It is possible to treat the modifications of the object as a noise, too.

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Compositional Studies of Semiconductor Alloys by Bright Field Electron Microscope Imaging of Wedged Crystals

MRS Proceedings ◽

10.1557/proc-77-473 ◽

1986 ◽

Vol 77 ◽

Cited By ~ 6

Author(s):

D. J. Eaglesham ◽

C. J. D. Hetherington ◽

C. J. Humphreys

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Cross Section ◽

Bright Field Image ◽

Semiconductor Alloys ◽

Bright Field ◽

Transmission Electron ◽

Microscope Imaging ◽

Electron Microscope Imaging ◽

Section Sample

ABSTRACTThe use of a cleaved 90 degree wedge as a cross section sample for transmission electron microscopy allows the composition of III/V semiconductor alloys to be measured by studying the thickness fringes of the on-axis [010] bright field image. The effect is explained in terms of the incident electron Bloch states and is illustrated by reference to GaAs/AlGaAs. The technique has an accuracy of about 5% and a spatial resolution of a few Å. The range of materials that can be analysed in this way is discussed.

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Diffraction contrast and Huang scattering in dark-field imaging of diffusely scattered electrons

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100172607 ◽

1994 ◽

Vol 52 ◽

pp. 974-975

Author(s):

Z. L. Wang

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Diffuse Scattering ◽

Dark Field ◽

Bright Field Image ◽

High Angle ◽

Bright Field ◽

Local Lattice Distortion ◽

Local Composition ◽

Transmission Electron

It has been demonstrated that dark-field, atomic number sensitive images can be obtained either inscanning transmission electron microscopy (STEM) using a high-angle annular dark field detector (HAADF) or in transmission electron microscopy (TEM) using an on-axis objective aperture under the hollow cone beam illumination. The images are formed using the high-angle diffusely scattered electrons presuming that the high angle Bragg reflections are weak. Diffuse scattering can be generated by both thermal diffuse scattering (TDS) and Huang scattering, The local lattice distortion due to the presence of defects, dislocations, lattice relaxation, surfaces, or interfaces, is a source for generating diffuse scattering (or Huang scattering). In these cases, the final image contrast may not be sensitive to the local composition, thus eliminating the Zcontrast effect. The diffraction effect in the imagesformed by diffusely scattered electrons is easily seen in the TEM case. In the diffraction pattern of gold shown in Fig. 1, <110> streaks produced by TDS are clearly seen. The bright field image shows some bending and strain contrast. Most of the features observed in the bright field imageappear in the dark field image of the diffusely scattered electrons.

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Epitaxial Platinum Films on (0001) Sapphire: a Microstructural Study

Microscopy and Microanalysis ◽

10.1017/s143192760003467x ◽

2000 ◽

Vol 6 (S2) ◽

pp. 436-437

Author(s):

S. Ramanathan ◽

B.M. Clemens ◽

P.C. Mclntyre ◽

U. Dahmen

Keyword(s):

Electron Microscopy ◽

Seed Layer ◽

Bright Field Image ◽

Spot Pattern ◽

Bright Field ◽

Plan View ◽

Microstructural Study ◽

Transmission Electron ◽

Pt Films ◽

Seed Layers

Epitaxial platinum films are used as seed layers in a number of magnetic and ferroelectric devices. It is hence very important to understand the microstructure of the seed layer to control the subsequent multilayer growth. Previous studies of epitaxial Pt films have focused on AFM, XRD and RHEED measurements. However, there has been no detailed analysis of the microstructure as of yet. In this paper, we present results of a systematic study of the microstructure of epitaxial Pt films using conventional and high resolution transmission electron microscopy.Platinum films were grown by sputtering in an UHV chamber at 500°C on (0001) sapphire. Figure 1 shows a plan view bright field image of a Pt film with the inset showing the <111> diffraction pattern. The spot pattern confirms the epitaxial nature of the film.

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Arsenic segregation in polysilicon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074604 ◽

1983 ◽

Vol 41 ◽

pp. 154-155 ◽

Cited By ~ 1

Author(s):

P.E. Batson ◽

C.R.M. Grovenor ◽

D.A. Smith ◽

C. Wong

Keyword(s):

Incident Beam ◽

Silicon Wafers ◽

Chemical Polishing ◽

Bright Field Image ◽

Beam Size ◽

Stem Analysis ◽

Bright Field ◽

Twin Boundaries ◽

X Ray ◽

Line Scan

In this work As doped polysilicon was deposited onto (100) silicon wafers by APCVD at 660°C from a silane-arsine mixture, followed by a ten minute anneal at 1000°C, and in one case a further ten minute anneal at 700°C. Specimens for TEM and STEM analysis were prepared by chemical polishing. The microstructure, which is unchanged by the final 700°C anneal,is shown in Figure 1. It consists of numerous randomly oriented grains many of which contain twins.X-ray analysis was carried out in a VG HB5 STEM. As K α x-ray counts were collected from STEM scans across grain and twin boundaries, Figures 2-4. The incident beam size was about 1.5nm in diameter, and each of the 20 channels in the plots was sampled from a 1.6nm length of the approximately 30nm line scan across the boundary. The bright field image profile along the scanned line was monitored during the analysis to allow correlation between the image and the x-ray signal.

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Lattice Imaging of Twin, Lath and α/Martensite Boundaries in Duplex Low Carbon Steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078195 ◽

1977 ◽

Vol 35 ◽

pp. 118-119

Author(s):

J. Y. Koo ◽

G. Thomas

Keyword(s):

High Resolution Electron Microscopy ◽

Ferrite Matrix ◽

Carbon Steels ◽

Bright Field Image ◽

Low Carbon ◽

Lattice Imaging ◽

Bright Field ◽

Lattice Image ◽

New Information ◽

Resolution Electron

High resolution electron microscopy has been shown to give new information on defects(1) and phase transformations in solids (2,3). In a continuing program of lattice fringe imaging of alloys, we have applied this technique to the martensitic transformation in steels in order to characterize the atomic environments near twin, lath and αmartensite boundaries. This paper describes current progress in this program.Figures A and B show lattice image and conventional bright field image of the same area of a duplex Fe/2Si/0.1C steel described elsewhere(4). The microstructure consists of internally twinned martensite (M) embedded in a ferrite matrix (F). Use of the 2-beam tilted illumination technique incorporating a twin reflection produced {110} fringes across the microtwins.

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A Newly Designed 650kv Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101268 ◽

1968 ◽

Vol 26 ◽

pp. 304-305

Author(s):

K. Shiraishi ◽

T. Katsuta ◽

S. Ozasa ◽

H. Todokoro

Keyword(s):

Electron Microscope ◽

High Voltage ◽

Bright Field Image ◽

Bright Field ◽

Push Button ◽

Condenser Lens ◽

High Voltage Generator ◽

Frequency Power ◽

Better Than ◽

Illuminating System

We have recently completed a newly designed 650KV electron microscope. An external view of this advanced instrument is shown in Figure 1. A symmetrical Cockcroft-Walton circuit has been adopted as the high voltage generator. The cathode is heated by high frequency power; a battery is not employed. The high voltage stability is better than 1 x 10-5/min.The sectional diagram of the column shown in Figure 2 is 420mm in diameter and 2750mm in height. The illuminating system consists of a double condenser lens and a magnetic alignment device. Dual deflector assemblies for dark and bright field images, selectable by push button, are built beneath the condenser lens. Two selectable stigmator power supplies are also provided for dark and bright field image operation.

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Scanning Secondary Electron Microscopy of Myofibrils Using Transmission Techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116401 ◽

1975 ◽

Vol 33 ◽

pp. 556-557

Author(s):

M. K. Lamvik

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Carbon Films ◽

Photographic Recording ◽

Transmission Electron ◽

Thin Carbon ◽

The Common ◽

Scanning Electron ◽

Better Than ◽

Cellular Organelles

When observing small objects such as cellular organelles by scanning electron microscopy, it is often valuable to use the techniques of transmission electron microscopy. The common practice of mounting and coating for SEM may not always be necessary. These possibilities are illustrated using vertebrate skeletal muscle myofibrils.Micrographs for this study were made using a Hitachi HFS-2 scanning electron microscope, with photographic recording usually done at 60 seconds per frame. The instrument was operated at 25 kV, with a specimen chamber vacuum usually better than 10-7 torr. Myofibrils were obtained from rabbit back muscle using the method of Zak et al. To show the component filaments of this contractile organelle, the myofibrils were partially disrupted by agitation in a relaxing medium. A brief centrifugation was done to clear the solution of most of the undisrupted myofibrils before a drop was placed on the grid. Standard 3 mm transmission electron microscope grids covered with thin carbon films were used in this study.

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New minerals tsangpoite Ca5(PO4)2(SiO4) and matyhite Ca9(Ca0.5□0.5)Fe(PO4)7 from the D'Orbigny angrite

Mineralogical Magazine ◽

10.1180/mgm.2018.125 ◽

2018 ◽

Vol 83 (02) ◽

pp. 293-313 ◽

Cited By ~ 1

Author(s):

Shyh-Lung Hwang ◽

Pouyan Shen ◽

Hao-Tsu Chu ◽

Tzen-Fu Yui ◽

Maria-Euginia Varela ◽

...

Keyword(s):

Electron Microscopy ◽

Raman Spectroscopy ◽

Electron Diffraction ◽

Grain Boundary ◽

Electron Probe ◽

Formation Mechanisms ◽

Formula Unit ◽

Micro Raman Spectroscopy ◽

The Common ◽

Oxygen Atoms

AbstractTsangpoite, ideally Ca5(PO4)2(SiO4), the hexagonal polymorph of silicocarnotite, and matyhite, ideally Ca9(Ca0.5□0.5)Fe(PO4)7, the Fe-analogue of Ca-merrillite, were identified from the D'Orbigny angrite meteorite by electron probe microanalysis, electron microscopy and micro-Raman spectroscopy. On the basis of electron diffraction, the symmetry of tsangpoite was shown to be hexagonal,P63/morP63, witha= 9.489(4) Å,c= 6.991(6) Å,V= 545.1(6) Å3andZ= 2 for 12 oxygen atoms per formula unit, and that of matyhite was shown to be trigonal,R3c, witha= 10.456 (7) Å,c= 37.408(34) Å,V= 3541.6 (4.8) Å3andZ= 6 for 28 oxygen atoms per formula unit. On the basis of their constant association with the grain-boundary assemblage: Fe sulfide + ulvöspinel + Al–Ti-bearing hedenbergite + fayalite–kirschsteinite intergrowth, the formation of tsangpoite and matyhite, along with kuratite (the Fe-analogue of rhönite), can be readily rationalised as crystallisation from residue magmas at the final stage of the D'Orbigny meteorite formation. Alternatively, the close petrographic relations between tsangpoite/matyhite and the resorbed Fe sulfide rimmed by fayalite + kirschsteinite symplectite, such as the nucleation of tsangpoite in association with magnetite ± other phases within Fe sulfide and the common outward growth of needle-like tsangpoite or plate-like matyhite from the fayalite–kirschsteinite symplectic rim of Fe sulfide into hedenbergite, infer that these new minerals and the grain-boundary assemblage might represent metasomatic products resulting from reactions between an intruding metasomatic agent and the porous olivine–plagioclase plate + fayalite-kirschsteinite overgrowth + augite + Fe sulfide aggregates. Still further thermochemical and kinetics evidence is required to clarify the exact formation mechanisms/conditions of the euhedral tsangpoite, matyhite and kuratite at the grain boundary of the D'Orbigny angrite.

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