Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

scholarly journals Reducing Electron Beam Damage with Multipass Transmission Electron Microscopy

2017 ◽  
Vol 23 (S1) ◽  
pp. 1794-1795 ◽  
Author(s):  
Colin Ophus ◽  
Thomas Juffmann ◽  
Stewart A Koppell ◽  
Brannon B Klopfer ◽  
Robert Glaeser ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Transmission Electron ◽  
Beam Damage

STEM versus CTEM beam damage: paraffin single crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 496-497
Author(s):  
S. J. Krause ◽  
L. F. Allard ◽  
W. C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Large Diameter ◽  
High Flux ◽  
Scanning Electron Beam ◽  
Sample Area ◽  
Transmission Electron ◽  
Beam Damage ◽  
Scanning Electron

Introduction Currently, the resolution of structural detail in conventional transmission electron microscopy (CTEM) of organic materials is limited by the electron beam damage suffered by the sample. It has recently been shown that the imaging modes now available in scanning transmission electron microscopy (STEM) provide the potential for improvements in resolution over CTEM methods. However, the effect of the sensitivity of an organic sample itself to beam damage has not been compared in STEM versus CTEM. In STEM each element of the sample area is briefly illuminated with a small diameter, high flux, scanning electron beam, whereas in CTEM the entire sample area is continuously illuminated with a large diameter, lower flux, static electron beam. Although it has been shown that the amount of sample damage in CTEM is independent of dose rate(2), the electron flux in STEM may range from 3 to 4 orders of magnitude greater than that in CTEM, with a possible influence on damage rate. Generally, the effects of beam size, high flux, and short dwell time of the scanning electron beam on sensitivity of the sample to damage in STEM are not known.

Transmission electron microscopy of coexisting low-tridymite polymorphs

1989 ◽  
Vol 53 (369) ◽  
pp. 89-97 ◽  
Author(s):  
J. R. Ashworth
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Crystal Structures ◽  
Layer Plane ◽  
Twin Boundaries ◽  
Transmission Electron ◽  
Diffraction Patterns

AbstractThree polymorphs of tridymite (MC, PO-10 and MX) have been examined by transmission electron microscopy (TEM), in crystals which also contain lamellae of cristobalite. MX is the least common, and is highly unstable in the electron beam. It occurs as small regions (< 1 µm2) in PO-10 tridymite and at MC/PO-10 boundaries; these regions are interpreted as being strained. A consistent association between PO-10 and the cristobalite lamellae is attributed to the fact that PO-10 can more closely match the low-cristobalite structure than MC can, at boundaries parallel to the plane in which the crystal structures contain layers of SiO4 tetrahedra. An analogous interpretation explains the observation that twin boundaries (associated with 60° or 120° rotation of the layer) are commonly parallel to the layer plane in PO-10 but at high angles to it in MC. Abundant lamellar features, parallel to the same plane in PO-10, are tentatively interpreted as representing twinning by reflection and 180° rotation, which may also account for c* streaking in diffraction patterns.

In-Situ Transmission Electron Microscopy Studies of the Oxidation of Si (111) 7X7

1989 ◽  
Vol 159 ◽  
Author(s):  
J.M. Gibson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
Electron Diffraction ◽  
High Energy ◽  
Energy Transmission ◽  
Transmission Electron Diffraction ◽  
Transmission Electron

ABSTRACTThe kinematical approximation is valid for High-Energy Transmission Electron Diffraction from monolayers in planview. We use this fact to study quantitatively the attack of Si (111) 7×7 by 02. Oxygen is found to bind in the bridging position of the adatom backbonds and render the structure very stable during subsequent 02 exposure. Electron-beam exposure during dosing additionally creates rapid disordering which is presumed to represent SiOx formation.

scholarly journals Damage and recovery induced by a high energy e-beam in a silicon nanofilm

RSC Advances ◽  
2017 ◽  
Vol 7 (59) ◽  
pp. 37032-37038 ◽  
Author(s):  
Xianlin Qu ◽  
Qingsong Deng
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Silicon Thin Film ◽  
Transmission Electron

Herein, electron beam-induced damage and recovery of a silicon thin film was investigatedin situ viatransmission electron microscopy (TEM).

The Panoramic Rheed Patterns

1990 ◽  
Vol 48 (1) ◽  
pp. 324-325
Author(s):  
Yootaek Kim ◽  
Tung Hsu
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Electron Diffraction ◽  
Incidence Angle ◽  
High Energy ◽  
Rheed Pattern ◽  
Crystal Surfaces ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
Reflection Electron Microscopy

When applying the reflection high energy electron diffraction (RHEED) and reflection electron microscopy (REM) methods[1] on the study of crystal surfaces it is necessary to index the RHEED spots and recognize the azimuth of the electron beam direction. This can be difficult because the RHEED pattern, unlike the transmission electron diffraction (TED) pattern, is distorted by the inner potential of the specimen and only one half of the pattern is shown. We found that it is useful, at the beginning of working on a certain surface of a certain crystal, to record a panoramic RHEED pattern by rotating the crystal through a large azimuth angle. This produces a map which is similar to the Kikuchi maps[2] used in transmission electron microscopy (TEM).Two examples of these panoramic RHEED patterns, one from the Pt(111) [3] and the other from α-Al203 (0001) [4,5,6), are shown in Figs. 1 and 2.The transmission Kikuchi maps are recorded using a specimen of suitable thickness such that the Kikuchi lines are strong and the diffraction spots are practically invisible. On the contrary, in making the panoramic RHEED patterns (or RHEED maps) we have no control over the thickness of the specimen. The electron beam enters and exits the same surface of the crystal; therefore, the relative intensities of the Bragg diffracted spots and the Kikuchi lines are not adjustable. The only adjustment lies in choosing the accelerating voltage and the incidence angle of the electrons such that the RHEED pattern has relatively low diffuse scattering.

Overcoming the problems of high-resolution transmission electron microscopy of biogenic aragonite

1990 ◽  
Vol 54 (377) ◽  
pp. 589-592 ◽  
Author(s):  
S. E. Ness ◽  
D. W. Haywick ◽  
C. Cuff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Carbonate Minerals ◽  
Biogenic Carbonate ◽  
Transmission Electron ◽  
Before And After ◽  
Diffraction Patterns ◽  
Exposure Technique

AbstractHigh-resolution transmission electron microscopy of biogenic carbonate minerals is hampered by a lack of stability during exposure to the electron beam. However, aragonite in bivalve shells may be successfully imaged using a modification of the ‘minimal-exposure technique’ of Williams and Fisher (1970). Diffraction patterns taken before and after beam exposure indicate that the aragonite remained stable during imaging. The procedure described here should prove useful for further studies of the ultrastructure and/or the diagenesis of biogenic carbonate minerals.

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