A directional, low energy electron detector employing channel electron multipliers.
Directional low energy electron detector using channel electron multipliers, noting electron detection efficiency and proton detection efficiency
Sharber, J. R.↗
SEARCH · Search NASA
Results for “ELECTRON CHANNELING”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Rapid misfit dislocation characterization in heteroepitaxial III-V/Si thin films by electron channeling contrast imaging
Electron channeling contrast imaging (ECCI) is used to characterize misfit dislocations in heteroepitaxial layers of GaP grown on Si(100) substrates. Electron channeling patterns serve as a guide to tilt and rotate sample orientation so that imaging can occur under specific diffraction conditions. This leads to the selective contrast of misfit dislocations depending on imaging conditions, confirmed by dynamical simulations, similar to using standard invisibility criteria in transmission electron microscopy (TEM). The onset and evolution of misfit dislocations in GaP films with varying thicknesses (30 to 250 nm) are studied. This application simultaneously reveals interesting information about misfit dislocations in GaP/Si layers and demonstrates a specific measurement for which ECCI is preferable versus traditional plan-view TEM.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Shubnikov–de Haas–like Quantum Oscillations in Artificial One-Dimensional LaAlO 3 / SrTiO 3 Electron Channels
Not Available
Cheng, Guanglei↗
Low energy charged particle detection using the continuous channel electron multiplier.
Continuous channel electron multiplier with saturated pulse independent of excitation for low energy charged particle detection
ELECTRON MULTIPLIER↗
Blanking method for continuous channel electron multipliers
Continuous channel electron multipliers /Channeltron/ gain improvement via blanking method avoid detection of unwanted particles
Donnelly, D. P.↗
Comparison of Dislocation Characterization by Electron Channeling Contrast Imaging and Cross-Correlation Electron Backscattered Diffraction
The characterization and quantification of dislocations is predominately carried out using transmission electron microscopy (TEM). Nevertheless, the sample preparation necessary for TEM foils can be cumbersome and possibly introduce defects. Two other techniques for characterizing and quantifying dislocations are electron channeling contrast imaging (ECCI) and cross-correlation electron backscattered diffraction (CC-EBSD). ECCI is similar to TEM in that specific imaging (channeling or diffraction) conditions need to be established, but is carried out in a scanning electron microscope on bulk samples, resulting in less complex sample preparation. CC-EBSD measures subtle changes in orientation measured from EBSD patterns to calculate elastic strains and the Nye tensor to deduce and map the total geometrically necessary dislocation (GND) content. Furthermore, this work presented here compares the capabilities of ECCI and CC-EBSD to map dislocations generated from nanoindentation.
42 ENGINEERING↗
Comparison of dislocation characterization by electron channeling contrast imaging and cross-correlation electron backscattered diffraction
In this paper, the relative capabilities and limitations of electron channeling contrast imaging (ECCI) and cross-correlation electron backscattered diffraction (CC-EBSD) have been assessed by studying the dislocation distributions resulting from nanoindentation in body centered cubic Ta. Qualitative comparison reveals very similar dislocation distributions between the CC-EBSD mapped GNDs and the ECC imaged dislocations. Approximate dislocation densities determined from ECC images compare well to those determined by CC-EBSD. Nevertheless, close examination reveals subtle differences in the details of the distributions mapped by these two approaches. Finally, the details of the dislocation Burgers vectors and line directions determined by ECCI have been compared to those determined using CC-EBSD and reveal good agreement.
36 MATERIALS SCIENCE↗
The application of channel electron multipliers to scanning electron microscopy Progress report
Channel electron multipliers for cathode luminescent collection of topographic details
Shaw, D. A.↗
Low energy charged-particle detection using the continuous-channel electron multiplier.
Windowless continuous-channel electron multiplier detecting low energy charged particles in space
ELECTRON MULTIPLIER↗
Comparative Response of Microchannel Plate and Channel Electron Multiplier Detectors to Penetrating Radiation in Space
Channel electron multiplier (CEM) and microchannel plate (MCP) detectors are routinely used in space instrumentation for measurement of space plasmas. Here, our goal is to understand the relative sensitivities of these detectors to penetrating radiation in space, which can generate background counts and shorten detector lifetime. We use 662 keV γ-rays as a proxy for penetrating radiation such as γ-rays, cosmic rays, and high-energy electrons and protons that are ubiquitous in the space environment. We find that MCP detectors are ~20 times more sensitive to 662 keV γ-rays than CEM detectors. This is attributed to the larger total area of multiplication channels in an MCP detector that is sensitive to electronic excitation and ionization resulting from the interaction of penetrating radiation with the detector material. In contrast to the CEM detector, whose quantum efficiency ε γ for 662 keVγ -rays is found to be 0.00175 and largely independent of detector bias, the quantum efficiency of the MCP detector is strongly dependent on the detector bias, with a power law index of 5.5. Lastly, background counts in MCP detectors from penetrating radiation can be reduced using MCP geometries with higher pitch and smaller channel diameter.
79 ASTRONOMY AND ASTROPHYSICS↗
Characterization of encapsulated quantum dots via electron channeling contrast imaging
A method for characterization of encapsulated epitaxial quantum dots (QD) in plan-view geometry using electron channeling contrast imaging (ECCI) is presented. The efficacy of the method, which requires minimal sample preparation, is demonstrated with proof-of-concept data from encapsulated (sub-surface) epitaxial InAs QDs within a GaAs matrix. Imaging of the QDs under multiple diffraction conditions is presented, establishing that ECCI can provide effectively identical visualization capabilities as conventional two-beam transmission electron microscopy. This method facilitates rapid, non-destructive characterization of sub-surface QDs giving immediate access to valuable nanostructural information.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Low energy charged particle detection using the continuous channel electron multiplier
Low energy charged particle detection with continuous channel electron multiplier
CHARGED PARTICLE↗
Continuous channel electron multiplier operated in the pulse saturated mode.
Continuous channel electron multiplier operated in pulse saturated mode, noting space charge limiting as major cause of gain saturation
SATURATION↗
Degradation of continuous-channel electron multipliers in a laboratory operating environment.
Continuous-channel electron multipliers degradation in spacecraft environment simulation laboratory equipment
Frank, L. A.↗
Multi-channel electronically scanned cryogenic pressure sensor
A miniature, multi-channel, electronically scanned pressure measuring device uses electrostatically bonded silicon dies in a multielement array. These dies are bonded at specific sites on a glass, prepatterned substrate. Thermal data is multiplexed and recorded on each individual pressure measuring diaphragm. The device functions in a cryogenic environment without the need of heaters to keep the sensor at constant temperatures.
Chapman, John J.↗
Ion detection using a continuous channel electron multiplier
Heavy positive ions pulse counting by spiral-type continuous channel electron multipier, noting long pulse rise time composed of numerous after pulsing
Adler, I.↗
Use of open-structure channel electron multipliers in sounding rocket experiments.
The performance of open-structure channel electron multipliers has been investigated in a laboratory simulation of the ascent pressure profile for a typical sounding rocket. The results of this test demonstrate that evacuation of the payload prior to launch is necessary for experiments where stability of response is an essential parameter.
Timothy, J. G.↗
Cleaning of contaminated channel electron multiplier arrays.
Polymerized organic materials found in vacuum systems frequently contaminate the individual channels (which can be as small as 15 microns) of an oil-pumped channel electron multiplier array used as a vacuum UV- to visible-radiation conversion device. It is shown that exposure to an oxygen plasma is an effective means of decontaminating the channels, thereby restoring the sensitivity of the device.
Harlow, F. E.↗