نتایج جستجو برای: thermionic electron emission

تعداد نتایج: 473143  

Journal: :The Review of scientific instruments 2009
J Fang Anatoly E Dementyev Jacques Tempere Isaac F Silvera

We study two techniques to create electrons in a liquid helium environment. One is thermionic emission of tungsten filaments in a low temperature cell in the vapor phase with a superfluid helium film covering all surfaces; the other is operating a glowing filament immersed in bulk liquid helium. We present both the steady state and rapid sweep I-V curves and the electron current yield. These cu...

2004
André Anders

Arc and glow discharges are defined based on their cathode processes. Arcs are characterized by collective electron emission, which can be stationary with hot cathodes (thermionic arcs), or nonstationary with cold cathodes (cathodic arcs). A brief review on cathodic arc properties serves as the starting point to better understand arcing phenomena in sputtering. Although arcing occurs in both me...

Journal: :Nuclear Fusion 2022

Abstract Reliable modeling of macroscopic melt motion induced by fast transients requires the accurate and computationally efficient description emitted current density that escapes to pre-sheath. The ITER sheaths surround hot tungsten surfaces during edge-localized modes are characterized important contributions from secondary electron emission backscattering as well coupling between thermioni...

2010
Tyler L. Westover Aaron D. Franklin Baratunde A. Cola Timothy S. Fisher Ronald G. Reifenberger

Carbon nanotubes CNTs are promising candidates to create new thermionicand photoemission materials. Intercalation of CNTs with alkali metals, such as potassium, greatly reduces their work functions, and the low electron scattering rates of small-diameter CNTs offer the possibility of efficient photoemission. This work uses a Nd:YAG YAG denotes yttrium aluminum garnet laser to irradiate singlean...

Journal: :Environmental Health Perspectives 1974
Ivan B. Rubin Carl J. Maggiore

The identification and characterization of microparticles has become an important field of study in recent years due to their presence in the environment and association with pathogenesis. Asbestos fibers have been intensively studied for these reasons. Since conventional microscopy has not provided unique identification of these materials, electron probe microanalysis, which yields chemical da...

Journal: :Physical review letters 2005
Adi Salomon Till Boecking Calvin K Chan Fabrice Amy Olga Girshevitz David Cahen Antoine Kahn

Electron transport through Si-C bound alkyl chains, sandwiched between and Hg, is characterized by two distinct types of barriers, each dominating in a different voltage range. At low voltage, the current depends strongly on temperature but not on molecular length, suggesting transport by thermionic emission over a barrier in the Si. At higher voltage, the current decreases exponentially with m...

1999
G. L. Belenky

We propose and demonstrate a purely electrical method for measuring the effective temperature T, of majority carriers under the injection of hot minority carriers. The T, of holes in a thin p-type InGaAs layer, heated by electron injection from an InAlAs layer in a three-terminal lattice-matched heterostructure, was determined by measuring the thermionic emission current of holes over another s...

2006
D. B. Melrose

The dominant emission from bare strange stars is thought to be electron-positron pairs, produced through spontaneous pair creation (SPC) in a surface layer of electrons tied to the star by a superstrong electric field. The positrons escape freely, but the electrons are directed towards the star and quickly fill all available states, such that their degeneracy suppresses further SPC. An electron...

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