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Results for “electron beam”

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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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Electron beam, laser beam and plasma arc welding studies

This program was undertaken as an initial step in establishing an evaluation framework which would permit a priori selection of advanced welding processes for specific applications. To this end, a direct comparison of laser beam, electron beam and arc welding of Ti-6Al-4V alloy was undertaken. Ti-6Al-4V was selected for use in view of its established welding characteristics and its importance in aerospace applications.

Banas, C. M.↗
DOE OSTI2026

Evaluation of accuracy and resolution of the electron beam profile scanner at the Fermilab Main Injector

The objective of this work is to assess the accuracy of measurements made by the Electron Beam Profile Scanner (EBPS), which captures the trajectory of an electron beam with and without a proton beam present. The proton beam induces deflection in the electron beam, which is influenced by proton charges.For high-resolution images, the probe beam needs to be of high intensity, small diameter, and small divergence, evaluated using a YAG screen and an optical transition radiation (OTR) screen. Additionally, the point spread function (PSF) will be calculated to characterize the optical system's properties using ZEMAX software. The capabilities of the Hamamatsu Charge-Injection Device (CID) camera and Kimball Physics electron gun (e-gun) will be considered for accuracy.

Mwaniki, Matilda [IIT, Chicago; Fermilab]↗
NASA NTRS1973

Electron beam controller

An electron beam device which extracts energy from an electron beam before the electrons of the beam are captured by a collector apparatus is described. The device produces refocusing of a spent electron beam by minimizing tranverse electron velocities in the beam where the electrons, having a multiplicity of axial velocities, are sorted at high efficiency by collector electrodes.

Kosmahl, H. G.↗
DOE OSTI2026

Conditional diffusion machine-learning framework for mapping valence electron distribution from convergent beam electron diffraction

Quantitative convergent beam electron diffraction (CBED) enables determination of aspherical valence electron distributions through refinement of low-order structure factors, which are highly sensitive to chemical bonding and charge density variations. However, conventional quantitative CBED (QCBED) requires solving a highly nonlinear inverse problem with many coupled parameters, and computationally intensive dynamical diffraction calculations, making it time-consuming and difficult to apply to complex systems. More broadly, reconstructing charge density and orbital electron distribution from diffraction data has long been a central challenge in both x-ray and electron crystallography. Here, in this study, we introduce an artificial-intelligence (AI)-based framework that replaces traditional refinement with a data-driven inverse solver. Using a large synthetic CBED dataset generated by Bloch-wave simulations, we train a conditional diffusion model to directly infer crystal structural parameters and multipole density formalism parameters, and hence valence electron distributions, from CBED patterns alone. By learning from forward simulations across realistic parameter space, the model effectively solves the inverse problem. Compared with direct regression approaches, the diffusion-based framework provides posterior parameter distributions for rigorous uncertainty quantification while preserving quantitative fidelity and reducing analysis time by orders of magnitude. By eliminating the need for external single-crystal x-ray diffraction data and complex nonlinear refinement, this approach enables practical, high-throughput, and in situ quantitative CBED, enabling real-time mapping of valence electron distributions and their correlation with functional responses in quantum and energy materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2025

Spatial profile of argon (1s 5 ) metastables in an electron beam generated plasma

Electron beams with an applied magnetic field generate a secondary cold plasma with a selective chemical composition, featuring low-energy ions and metastable species in the discharge periphery, ideal for low-damage plasma treatment of material substrates. In this work, we studied the plasma generated by an e-beam using a 4 kV voltage in a pure argon gas environment under a magnetic field of 150 G and in the pressure range of 25–90 mTorr. We measured the absolute spatial density profile of argon (1 s 5 ) metastables in an electron beam generated plasma by laser-induced fluorescence and found it to be of the order of 10 16 m −3 . The electron temperature and the electron density measured by a Langmuir probe were of the order of 10 16 m −3 and less than an eV respectively. Electron-impact quenching was identified as a significant loss mechanism for the Ar(1s 5 ) state, leading to the saturation of the metastable density at higher pressures. Outside the primary ionization region, the spatial distribution of argon metastables followed a linear diffusion profile, indicating negligible additional production in those regions.

EEDF↗
DOE OSTI2025

The effect of filament peaking on electron beam weld quality

Electron beam welding uses high intensity beams that are generated by an electron emitting cathode under high vacuum conditions. The cathode, typically a ribbon or wire filament of refractory metal, must be heated to sufficiently high temperatures for electron emission to occur and must be carefully controlled to produce the desired beam current while at the same time optimizing filament lifetime. Traditional methods for doing this in commonly used triode gun assemblies consist of first finding the filament knee point in the filament current versus beam current relationship that produces the desired beam current for a given beam voltage. The filament current is then increased by some amount, typically 5–10%, per conventional wisdom to produce a peaked beam. This investigation studies and quantifies the beam and weld quality produced by underkneed and overpeaked filaments using electron beam diagnostics to measure the power density distribution of these beams. Underkneed filaments are shown to have power densities that drop off very quickly below the traditional knee, resulting in poor weld penetration. Kneed filaments do not reach the full beam intensity and also produce shallow welds. Increasing the filament current 10% above the traditional knee was shown to produce a circular Gaussian-like beam with peaked intensity optimized for welding and for filament lifetime. Further increases in the filament current that produce overpeaked beams do not significantly change the beam or weld quality and would only contribute to a reduced filament lifetime.

Electron Beam Welding↗
DOE OSTI2025

Quasilinear Analysis in the Source Region of Jovian Hectometric Emission Associated With Upward Electron Beams

Abstract Intense upward electron beams were measured by the Juno JADE instrument in the northern hemisphere, low‐latitude auroral zone source region. In this study we report on how these electron beams interact with plasma near and within the Jovian hectometric (HOM) emission (1 MHz 5 MHz) source region. Within the source region large upward loss cones are observed in the northern polar region at radial distances of 2Rj, magnetic latitude of . Intense, narrow electron beams ( 3 keV) are then observed, but within one second wave‐particle scattering is observed, filling the loss cone to energies 50 keV. These energies persist for several seconds before fading, leaving an empty loss cone again. The loss cone provides a free‐energy source for HOM emission resulting from the cyclotron maser instability. We use quasilinear analysis to examine the generation of HOM and the dynamics of wave‐particle interaction of the electron beams with HOM, and the generation via Landau interaction of whistler mode emission. The dynamic spectrum of the HOM emission generated by the loss‐cone electrons as well as that of the low‐frequency whistler‐mode waves generated by the up‐going electron beam can be constructed by quasilinear theory, which compare well with observation. The saturated state of the energetic electron velocity distribution function constructed via quasilinear theory also compare reasonably with observation.

Yoon, P. H. [Institute for Physical Science and Te↗
DOE OSTI2025

Development of a versatile plate spectrometer for electron beam characterization

A new instrument for electron beam characterization has been developed, based on measuring the range of beam electrons in different thicknesses of aluminum, to determine both the current and energy of an electron beam traveling in open air. This instrument is referred to as a ‘plate spectrometer’ as the thickness of the spectrometer is adjusted by adding or removing aluminum plates. This spectrometer was assembled and then characterized at the Idaho Accelerator Center (IAC) with three different beam energies and with one beam energy at the University of Maryland Radiation Facilities. The plate spectrometer was able to match the median energies and provide a reasonable constraint to the beam distributions seen in the IAC magnetic spectrometer. Finally, in a separate experiment, the plate spectrometer was also seen to agree with a dosimetry characterization of the beam at the University of Maryland Radiation Facilities and improved upon the uncertainties of this measurement.

43 PARTICLE ACCELERATORS↗