Study of CO radicals on magnesium oxide with electron paramagnetic resonance techniques.
Adsorption of CO radicals on three types of magnesium oxide using EPR techniques, noting spectrum of adsorbed radical, bonding, etc
MAGNETIC SPECTROSCOPY↗
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Results for “electron techniques”
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.
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Ballistic-Electron-Emission Microscopy Techniques for Nanometer-scale Characterization of Interfaces
Semiconductor interface properties are among the most important phenomena in materials science and technology. The study of metal/semiconductor Schottky barrier interfaces has been the primary focus of a large research and development community for decades. Throughout the long history of interface investigation, the study of interface defect electronic properties have been seriously hindered by the fundamental experimental difficulty of probing subsurface structures. A new method, Ballistic-Electron-Emission Microscopy (BEEM), has been developed which not only enables spectroscopic probing of subsurface interface properties, but also, provides nanometer-resolution imaging capabilities. BEEM employs Scanning Tunneling Microscopy (STM) and a unique spatially localized ballistic electron spectroscopy method...
Bell, L. D.↗
Electron energy loss spectroscopy techniques for the study of microbial chromium(VI) reduction
Electron energy loss spectroscopy (EELS) techniques were used to determine oxidation state, at high spatial resolution, of chromium associated with the metal-reducing bacteria, Shewanella oneidensis, in anaerobic cultures containing Cr(VI)O4(2-). These techniques were applied to fixed cells examined in thin section by conventional transmission electron microscopy (TEM) as well as unfixed, hydrated bacteria examined by environmental cell (EC)-TEM. Two distinct populations of bacteria were observed by TEM: bacteria exhibiting low image contrast and bacteria exhibiting high contrast in their cell membrane (or boundary) structure which was often encrusted with high-contrast precipitates. Measurements by EELS demonstrated that cell boundaries became saturated with low concentrations of Cr and the precipitates encrusting bacterial cells contained a reduced form of Cr in oxidation state + 3 or lower.
Evaluation Studies↗
Large-Angle Rocking Beam Electron Diffraction of Large Unit Cell Crystals Using Direct Electron Detector
We report a large-angle rocking beam electron diffraction (LARBED) technique for electron diffraction analysis. Diffraction patterns are recorded in a scanning transmission electron microscope (STEM) using a direct electron detector with large dynamical range and fast readout. We use a nanobeam for diffraction and perform the beam double rocking by synchronizing the detector with the STEM scan coils for the recording. Using this approach, large-angle convergent beam electron diffraction (LACBED) patterns of different reflections are obtained simultaneously. By using a nanobeam, instead of a focused beam, the LARBED technique can be applied to beam-sensitive crystals as well as crystals with large unit cells. Here, this paper describes the implementation of LARBED and evaluates the performance using silicon and gadolinium gallium garnet crystals as test samples. We demonstrate that our method provides an effective and robust way for recording LARBED patterns and paves the way for quantitative electron diffraction of large unit cell and beam-sensitive crystals.
4DSTEM↗
Application of electron backscatter diffraction techniques to quantify effects of aging on sub-grain and spatial heterogeneity in NMC cathodes
Identification and evaluation of structural heterogeneity in spent cathode materials is crucial to developing appropriate remediation strategies for novel recycling processes. Native heterogeneities may be exacerbated during the cell's operational lifetime, as sub-particle-scale variations induce anisotropic expansion and contraction upon cycling. Structural transformations resulting from repeated cycling and calendar aging predominantly occur at the secondary particle surface and at the grain boundaries (GBs) between primary particles. However, the diffusion and stress build up around and across GBs are poorly understood. In this study, electron backscatter diffraction (EBSD) is employed to track sub-grain lattice structure across a statistically relevant number of Li(Ni0.33Mn0.33Co0.33)O2 (NMC-111) particles. Specifically, differences in lattice misorientation – measured as the deviation from the grain's average orientation – are tracked as a function of position within the electrode (near current collector, middle, and near separator) and as a function of electrochemical cycling. Further, a novel method of structural analysis is developed, offering insight into sub-grain diffusion behavior by comparing lattice misorientation near the grain boundary versus in the grain bulk. The present results suggest that electrode-scale spatial heterogeneity in lattice structure is induced by initial manufacturing conditions, and that radial gradients in lattice misorientation evolve at the primary particle scale with repeated electrochemical cycling.
25 ENERGY STORAGE↗
A summary of the BARREL campaigns: Technique for studying electron precipitation
Explore the source record for details and available documents.
L. A. Woodger↗
Analytical study and experimental investigation of techniques for improving electron tubes for space application Final report
Elimination of electric cathode heaters and heat pipe cooling of high power microwave tubes as means of improving electron tubes for space application
Conway, E. C.↗
Improved electron beam welding technique
Energy transferred from the source to the workpiece is maximized by relying on the mobility of the material in its liquid phase. This permits more beam energy to transfer to the weld front.
Schumaker, B. W.↗
Testing methods and techniques: A compilation
Mechanical testing techniques, electrical and electronics testing techniques, thermal testing techniques, and optical testing techniques are the subject of the compilation which provides technical information and illustrations of advanced testing devices. Patent information is included where applicable.
Source record↗
Apparatus and technique for pulsed electron beam annealing for solar cell production
Many of the demands of high-throughput processing of solar cells can be satisfied by transient methods using pulsed electron beams. A prototype pulsed electron beam processor for solar cell production has been built, and is intended for automated annealing of solar cell junction ion implantation at a rate of 1200-1800 silicon wafers per hour. Other applications include solar cell junctions by pulse diffusion, annealing of ion-implanted back surface fields, and pulse sintering of cell metallization.
Landis, G. A.↗
Determination of Planetary Basalt Parentage: A Simple Technique Using the Electron Microprobe
Previous studies have demonstrated the usefulness of major and minor elements in silicate phases to understand differences among basaltic systems and the influence of different planetary environments on basalt chemistry (e.g., Papike [1]). Intriguing data displays presented by Papike [1] include a plot of Mn vs. Fe (atoms per formula unit, afu) for pyroxene and olivine and a plot showing the anorthite content of plagioclase from different planetary basalts. Here we combine portions of these plots (Fig. 4) and provide all new data for olivine and plagioclase.
Papike, J. J.↗
Quantitative Modeling of High-Energy Electron Scattering in Thick Samples Using Monte Carlo Techniques
Cryo-electron microscopy (cryo-EM) is a powerful tool for imaging biological samples but is typically limited by sample thickness, which is restricted to a few hundred nanometers depending on the electron energy. However, there is a growing need for imaging techniques capable of studying biological samples up to 10 µm in thickness while maintaining nanoscale resolution. This need motivates the use of mega-electron-volt scanning transmission electron microscopy (MeV-STEM), which leverages the high penetration power of MeV electrons to generate high-resolution images of thicker samples. In this study, we employ Monte Carlo simulations to model electron–sample interactions and explore the signal decay of imaging electrons through thick specimens. By incorporating material properties, interaction cross-sections for energy loss, and experimental parameters, we investigate the relationship between the incident and transmitted beam intensities. Key factors such as detector collection angle, convergence semi-angle, and the material properties of samples were analyzed. Our results demonstrate that the relationship between incident and transmitted beam intensities follows the Beer–Lambert law over thicknesses ranging from a few microns to several tens of microns, depending on material composition, electron energy, and collection angles. The linear depth of silicon dioxide reaches 3.9 µm at 3 MeV, about 6 times higher than that at 300 keV. Meanwhile, the linear depth of amorphous ice reaches 17.9 µm at 3 MeV, approximately 11.5 times higher than that at 300 keV. These findings are crucial for advancing the study of thick biological and semiconductor samples using MeV-STEM.
36 MATERIALS SCIENCE↗
Photoelectron spectroscopy by electron attachment
Technique detects threshold photoelectrons for atoms and molecules with high resolution, yet requires no electron optics setup.
Ajello, J. M.↗
Lunar remnant magnetic field mapping from orbital observations of mirrored electrons
A technique is described for mapping areas of lunar surface magnetism by observing ambient low-energy electrons from lunar orbit with a detector that is sectored to distinguish directions of arrival with respect to the ambient magnetic field and the lunar surface. It is noted that the ambient electrons provide a probe along the ambient magnetic-field lines down to the lunar surface for remote sensing of the presence of surface fields. Unlike direct magnetometer measurements, this probe does not require low altitude or a very stable ambient field in order to map the occurrence regions of such fields. Preliminary maps generated for the surface magnetic areas underlying the orbit of the Particles and Fields Satellite deployed from Apollo 16 are presented to demonstrate the feasibility of this technique.
Mccoy, J. E.↗
Instrumental and analytic techniques for separating protons from electrons in the cosmic ray flux
Techniques are being investigated to aid in distinguishing between electrons and the large background of interacting protons which simulate electron-induced electromagnetic cascades. For cosmic ray primaries, incident on the HECRE ionization spectrometer, statistical criteria are employed to test the cascade curves with the incident energy and starting point as free parameters. The physical significance of the distribution of apparent cascade starting points is being studied using Monte Carlo 100-GeV protons. The proposed use of a CsI detector module (totally-active and high Z) to further discriminate against protons is described.
Crannell, C. J.↗
Additive Manufacturing of Electronics for Space Applications
Additive manufacturing techniques for electronics will enable new detector and electronic assemblies that were not previously possible with traditional assembly processes. This technology has the potential to reduce mass and volume for fabrication and assembly of detector, instrument, and electronics concepts by printing fine feature sizes, printing on complex geometries, and allowing new concept production. This presentation summarizes efforts developing printing techniques to manufacture detectors and circuitry for two different space applications.
Additive Manufacturing↗
Nonequilibrium spherulitic magnetite in the Ryugu samples
Here, we have investigated several particles collected during each of two touchdowns of the Hayabusa2 spacecraft at the surface of the C-type asteroid 162173 Ryugu using various electron microscope techniques. Our detailed transmission electron microscopy study shows the presence of magnetite with various morphologies coexisting in close proximity. This is characteristic of CI chondrite-like materials and consistent with the mineral assemblages and compositions in the Ryugu parent body. We describe the microstructural characteristics of magnetite with different morphologies, which could have resulted from the chemical conditions (growth vs. diffusion rate) during their formation. Furthermore, we describe the presence of magnetites with a spherulitic structure composed of individual radiating fibers that are characterized by pervasive, homogeneously distributed euhedral to subhedral pores that have not been described in previous chondrite studies. This particular spherulitic structure is consistent with crystallization under nonequilibrium conditions. Additionally, the presence of a high density of defects within the magnetite fibers, the high surface/volume ratio of this morphology, and the presence of amorphous materials in several pores and at the edges of the acicular fibers further support their formation under nonequilibrium conditions. We suggest that the growth processes that lead to this structure result from the solution reaching a supersaturated state, resulting in an adjustment to a lower free energy condition via nucleation and rapid growth.
58 GEOSCIENCES↗