Relevant bibliographies by topics / Emissive cathode

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Academic literature on the topic 'Emissive cathode'

Author: Grafiati
Published: 31 August 2024

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Journal articles on the topic "Emissive cathode"

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Chaharsoughi, Mina Shiran, Mohammad Jafar Hadianfard, and Mohammad Mahdi Shiezadeh. "Study the Effect of Nanoemissive Materials on M-Type Cathode Performance." Advanced Materials Research 829 (November 2013): 772–77. http://dx.doi.org/10.4028/www.scientific.net/amr.829.772.

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In this study, the stoichiometric mixture of barium carbonate, calcium carbonate, and aluminum oxide with ratio of 5:3:2 was produced by two individual methods: sol-gel combustion and ball-milling method used as a precursor of electron emissive material on impregnated cathodes which make up high power vacuum microwave tubes such as klystrons. Results from X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy on emissive material produced by sol-gel combustion technique show that its crystallite size is under 45 nm, and particle size is less than 100 nm, and the chemical composition of emissive material is uniform at nanoscale. The effects of two types of emissive materials on operation properties of M type cathode were also investigated. The two types of manufactured M cathodes were tested inside an electron gun under maximum anode voltage 10.5 kV in continues wave mode, at 1100 ͦC, and the anode-cathode distance was fixed at 5 mm. results show that the emission current of M cathode impregnated by nano emissive materials is more uniform than conventional cathode, and its current density is about 2.7 A/cm2, while in I-V curve it does not reach at saturated-emission region at 10.5 kV.
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Stępińska, Izabela, Elżbieta Czerwosz, Mirosław Kozłowski, Halina Wronka, and Piotr Dłużewski. "Studies of field emission process influence on changes in CNT films with different CNT superficial density." Materials Science-Poland 36, no. 1 (May 18, 2018): 27–33. http://dx.doi.org/10.1515/msp-2018-0001.

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Abstract Field emission from materials at high electric fields can be associated with unfavorable or even destructive effect on the surface of the investigated cathode. The impact of high voltage electric power supply causes locally very strong electric fields focusing on the cathode surface. It causes a number of phenomena, which can adversely affect the morphology and the structure of the cathode material. Such a phenomenon is, for example, peeling of an emissive layer from the substrate or its burnout. It results in tearing of the layer and a decrease or loss of its ability to electrons emission. The cold cathodes in a form of CNT films with various CNTs superficial distribution are obtained by physical vapor deposition followed by chemical vapor deposition. CNTs are catalyzed in pyrolytic process with xylene (CVD), by Ni in a form of nanograins (few nm in size) placed in carbonaceous matrix. These films are built of emissive CNTs - carbonaceous film deposited on different substrates. In this work, the morphology and topography of superficial changes resulting from external electric field in such films were investigated.
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Isakova, Yulia I., Galina E. Kholodnaya, and Alexander I. Pushkarev. "Influence of Cathode Diameter on the Operation of a Planar Diode with an Explosive Emission Cathode." Advances in High Energy Physics 2011 (2011): 1–14. http://dx.doi.org/10.1155/2011/649828.

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This paper presents the results of experimental investigations into the current-voltage characteristics of a planar diode with an explosive emission cathode made from graphite. Studies were performed using a TEU-500 pulsed electron accelerator (350–500 keV, 100 ns, 250 J per pulse). Duration of diode operation, in a mode when electron current is limited by the emissive ability of the graphite cathode, is 15–20 ns. The contribution of the cathode periphery to total electron current appears only as an increase in the emissive surface area due to an expansion of explosive plasma. Investigations of an ion diode with a graphite cathode (plane and focusing geometry) were also carried out. Experiments were performed using a TEMP-4M ion accelerator, which forms two nanosecond pulses: the first negative pulse (150–200 kV, 300–600 ns) followed by the second positive (250–300 kV, 150 ns). Total diode current in the first pulse is well described by the Child-Langmuir law for electron current at a constant rate of plasma expansion, equal to 1.3 cm/μs. It is shown that for an area of flat cathode over 25 cm2, the influence of edge contribution does not exceed measurement error of total diode electron current (10%).
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Chen, Jing, Qianqian Huang, and Wei Lei. "Dual-Facets Emissive Quantum-Dot Light-Emitting Diode Based on AZO Electrode." Materials 15, no. 3 (January 19, 2022): 740. http://dx.doi.org/10.3390/ma15030740.

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We report on a green, dual emissive quantum-dot light-emitting diode (QLED) using alumina (Al)-doped ZnO (AZO) to adjust the band offset between the cathode and QD-emitting layers. The dual emissive QLED structure was designed by enhancing the efficient hole injection/transfer and slowing down the electron injection/transfer from AZO to the QD. The QLEDs presented a maximum luminance of 9450 cd/m2, corresponding to a power efficiency of 15.7 lm/W, a current efficiency of 25.5 cd/A, as well as a turn-on voltage of 2.3 V. It is worth noting that the performance of the dual emissive QLED is comparable to that of a single emissive QLED. Therefore, there is a 1.3-fold enhancement in the performance of the QLED based on the AZO cathode due to the balanced charge injection/transfer.
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Yang, Yang, Wen Zheng Yang, Wei Dong Tang, and Chuan Dong Sun. "Temperature Dependent Study of Carrier Diffusion in Photon Enhanced Thermionic Emission Solar Converters." Advanced Materials Research 772 (September 2013): 634–39. http://dx.doi.org/10.4028/www.scientific.net/amr.772.634.

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Photon Enhanced Thermionic Emission (PETE) is a novel concept in solar energy conversion, which can efficiently harvest solar energy at elevated temperatures. However, the temperature dependence of material parameters has not been clearly stated so far. In this study, a model for carrier transport is presented based on one dimension diffusion equation. Material data of GaAs are used to testify the temperature impact on material parameters. We find that for higher doped p-type GaAs which is suitable for PETE cathode material, its electron diffusion length shows weak temperature dependence. Carrier transport efficiency can be boosted by optimizing the geometry of the cathode and the optical parameters of the material. Finally, we propose a design of reflective mode cathode with reflective back surface and nanostructure emissive surface for PETE application.
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Nouzman, L., and G. L. Frey. "Directed migration of additives to form top interlayers in polymer light emitting diodes." Journal of Materials Chemistry C 5, no. 48 (2017): 12744–51. http://dx.doi.org/10.1039/c7tc04586g.

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Sibbett, W., S. C. Douglas, M. I. Harbour, B. A. Kerr, S. N. Spark, and Y. M. Saveliev. "Effect of cathode end caps and a cathode emissive surface on relativistic magnetron operation." IEEE Transactions on Plasma Science 28, no. 3 (June 2000): 478–84. http://dx.doi.org/10.1109/27.887651.

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Becatti, G., F. Burgalassi, F. Paganucci, M. Zuin, and D. M. Goebel. "Resistive MHD modes in hollow cathodes external plasma." Plasma Sources Science and Technology 31, no. 1 (January 1, 2022): 015016. http://dx.doi.org/10.1088/1361-6595/ac43c4.

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Abstract A significant number of plasma instabilities occur in the region just outside of hollow cathodes, depending on the injected gas flow, the current level and the application of an external magnetic field. In particular, the presence of an axial magnetic field induces a helical mode, affecting all the plasma parameters and the total current transported by the plasma. To explore the onset and behavior of this helical mode, the fluctuations in the plasma parameters in the current-carrying plume outside of a hollow cathode discharge have been investigated. The hollow cathode was operated at a current of 25 A, and at variable levels of propellant flow rate and applied magnetic fields. Electromagnetic probes were used to measure the electromagnetic fluctuations, and correlation analysis between each of the probe signals provided spatial-temporal characterization of the generated waves. Time-averaged plasma parameters, such as plasma potential and ion energy distribution function, were also collected in the near-cathode plume region by means of scanning emissive probe and retarding potential analyzer. The results show that the helical mode exists in the cathode plume at sufficiently high applied magnetic field, and is characterized by the presence of a finite electromagnetic component in the axial direction, detectable at discharge currents ⩾25 A. A theoretical analysis of this mode reveals that one possible explanation is consistent with the hypotheses of resistive magnetohydrodynamics, which predicts the presence of helical modes in the forms of resistive kink. The analysis has been carried out by linear perturbation of the resistive MHD equations, from which it is possible to obtain the dispersion relation of the mode and find the k–ω unstable branch associated with the instability. These findings provided the basis for more detailed investigation of resistive MHD modes and their effect in the plume of hollow cathodes developed for electric propulsion application.
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Yokoo, Kuniyoshi. "Experiments of highly emissive metal–oxide–semiconductor electron tunneling cathode." Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 14, no. 3 (May 1996): 2096. http://dx.doi.org/10.1116/1.588878.

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Hartmann, W., G. Kirkman, V. Dominic, and M. A. Gundersen. "A super-emissive self-heated cathode for high-power applications." IEEE Transactions on Electron Devices 36, no. 4 (April 1989): 825–26. http://dx.doi.org/10.1109/16.22493.

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Dissertations / Theses on the topic "Emissive cathode"

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Asselin, Daniel Joseph. "Characterization of the Near-Plume Region of a Low-Current Hollow Cathode." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/438.

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Electric propulsion for spacecraft has become increasingly commonplace in recent decades as designers take advantage of the significant propellant savings it can provide over traditional chemical propulsion. As electric propulsion systems are designed for very low thrust, the operational time required over the course of an entire mission is often quite long. The two most common types of electric thrusters both use hollow cathodes as electron emitters in the process of ionizing the propellant gas. These cathodes are one of the main life-limiting components of both ion and Hall thrusters designed to operate for tens of thousands of hours. Failure often occurs as a result of erosion by sputtering from high-energy ions generated in the plasma. The mechanism that is responsible for creating these high-energy ions is not well understood, and significant efforts have gone into characterizing the plasma produced by hollow cathodes. This work uses both a Langmuir probe and an emissive probe to characterize the variation of the plasma potential and density, the electron temperature, and the electron energy distribution function in the near plume region of a hollow cathode. The cathode used in this experiment is typical of one used in a 200-W class Hall thruster. Measurements were made to determine the variation of these parameters with radial position from the cathode orifice. Changes associated with varying the propellant and flow rate were also investigated. Results obtained from the cathode while running on both argon and xenon are shown. Two different methods for calculating the plasma density and electron temperature were used and are compared. The density and temperature were not strongly affected by reductions in the propellant flow rate. The electron energy distribution functions showed distinct shifts toward higher energies when the cathode was operated at lower flow rates. The plasma potential also displayed an abrupt change in magnitude near the cathode centerline. Significant increases in the magnitude of plasma potential oscillations at lower propellant flow rates were observed. Ions formed at the highest instantaneous plasma potentials may be responsible for the life-limiting erosion that is observed during long-duration operation of hollow cathodes.
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Sary, Gaétan. "Modélisation d'une cathode creuse pour propulseur à plasma." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30182/document.

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La cathode creuse est un élément clef des propulseurs à plasma. Dans un propulseur à plasma, un gaz propulsif est ionisé dans un canal de décharge puis accéléré hors de celui-ci afin de créer la poussée. Dans le propulseur de Hall en particulier, l'ionisation du gaz est provoquée par l'injection dans le canal de décharge d'un intense courant électronique (de quelques ampères à plus d'une centaine d'ampères). L'élément chargé de fournir le courant électronique de la décharge, la cathode creuse, est crucial dans le fonctionnement du propulseur. Or, celle-ci est souvent idéalisée dans les modèles de propulseur et n'est que rarement étudiée pour sa physique propre. Pourtant, le développement de propulseurs de Hall de haute puissance, destinés à terme à équiper l'ensemble des missions spatiales, requiert la mise au point de cathodes capable de délivrer un fort courant (jusqu'à plus de 100 A) sur des durées de l'ordre de la dizaine de milliers d'heures. Or, la mise au point de nouvelles cathodes s'est révélée difficile en raison de l'absence de modèle susceptible de prédire a priori les performances d'une cathode en fonction de sa conception. On se propose ici de mettre en place un modèle prédictif de cathode creuse capable de retranscrire la physique du fonctionnement de la cathode. L'objectif in fine est bien sûr d'utiliser ce modèle afin de faire le lien entre la conception de la cathode et son fonctionnement dans le but de guider le développement de futures cathodes. On présentera tout d'abord brièvement le contexte d'application des cathodes creuses, et on donnera un rapide aperçu du principe de fonctionnement global de la cathode. Ensuite, après avoir effectué un tour d'horizon des différents modèles numériques de cathode creuse préexistants dans la littérature, on détaillera le modèle de la cathode développé ici, qui incorpore une description fluide du plasma, ainsi que des transferts thermiques aux parois, qui conditionnent en grande partie le bon fonctionnement de la cathode. Un soin particulier sera apporté à la validation des résultats de simulation vis-à-vis des mesures expérimentales disponibles dans la littérature, ce qui nous permettra de perfectionner certains points du modèle afin de mieux traduire la réalité physique. En particulier, une modélisation spécifique de la région de transition entre la décharge interne de la cathode et la plume du propulseur sera réalisée. Ce modèle permettra de mettre en évidence certains phénomènes d'instabilité du plasma spécifiques de cette décharge, qui ont été jusqu'ici observés expérimentalement mais jamais pleinement intégrés aux modèles de cathode creuse. A l'aide du modèle validé, on procèdera à l'analyse physique de l'ensemble des phénomènes qui gouvernent le fonctionnement d'une cathode particulière, la cathode NSTAR développée par la NASA au Jet Propulsion Laboratory. Ensuite, on s'appuiera sur le modèle numérique pour comprendre l'impact sur le fonctionnement de la cathode des choix de conception au travers d'une étude paramétrique autour de la cathode NSTAR. Les tendances dégagées nous permettront de formuler des recommandations quant au développement de cathodes de haute puissance. Enfin, dans le but d'illustrer la versatilité du modèle développé, le comportement d'une cathode creuse employant une géométrie alternative à la cathode NSTAR sera également présenté
A hollow cathode is a critical component of plasma thrusters. In a plasma thruster, a propellant gas is ionized in a discharge chamber and accelerated out of it so as to generate thrust. In Hall thrusters in particular, the ionization of the gas is caused by an intense electron current (from a few to hundred amps) which flows through the discharge chamber. The hollow cathode is the device which is responsible for providing the discharge current. This key element is often idealized in thruster numerical models and its physical behavior is rarely studied for its own sake. Yet, developing high power Hall thrusters, designed to propel in the long run every type of space mission, requires new hollow cathodes able to supply an intense electron current (over 100 A) over a duration on the order of ten thousand hours. So far, designing new cathodes proved difficult because of the lack of model capable of predicting the performance of a cathode based on its design. In this work, we build up a predictive model of a hollow cathode capable of simulating the physics relevant to the operation of the cathode. In the end, we aim at using this model to associate design characteristics of the cathode to key aspects of the cathode performance during operation. Our goal with this model is to guide the development of future high power hollow cathodes. We will first briefly describe the range of application of hollow cathodes related to space propulsion. Then we will give a brief account of the working principles of the cathode and we will set the numerical models available in the literature prior to this one out. The numerical model developed in this work will then be described. It includes a fluid treatment of the plasma as well as an account of the heat fluxes to the walls which largely control the performance of the cathode. Simulation results will be thoroughly compared to experimental measurements available in the literature and specific aspects of the model will be refined to match up simulation results with the physical reality. For instance, a model that specifically represents the transition region between the internal plasma of the cathode and the plume of the cathode will be described. This model will enable us to highlight plasma instability phenomena which were so far observed experimentally, yet never properly included in hollow cathode models. Using the model just developed, we will analyze the physics of a particular hollow cathode which has been developed by NASA at the Jet Propulsion Laboratory, the NSTAR hollow cathode. Then, thanks to the numerical model, we will be able to carry out a parametric study revolving around the design of the NSTAR cathode. This will allow us to bring out the influence of the design on the cathode performance and we will eventually express recommendations regarding the design of future high power cathodes. To conclude, the versatility of the numerical model built up here will also be displayed through simulations of the behavior of a hollow cathode based on an alternate geometry
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Pagaud, Francis. "Control and stability of magnetised plasma columns : plasma-cathode interactions and helicon plasma operation." Electronic Thesis or Diss., Lyon, École normale supérieure, 2024. http://www.theses.fr/2024ENSL0016.

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Le transport, les ondes et les instabilités sont des problématiques courantes des plasmas magnétisés, à l’origine de problèmes fondamentaux et de limites opératoires pour les plasmas de fusion, les accélérateurs de particules à plasma ou la propulsion plasma. Le contrôle des propriétés du plasma est souhaitable mais complexe. Ce doctorat vise à utiliser une cathode émissive comme nouveau paramètre de contrôle et à comprendre la stabilité du plasma hélicon. Le dispositif expérimental est une enceinte à vide cylindrique de 80 cm de long et 20 cm de diamètre, connecté à un tube source en verre de 11 cm de diamètre. L’argon est injecté en continu à 0,13 Pa et ionisé par une antenne radio-fréquence inductive de 1 kW enroulée autour du tube source. Un champ magnétique de 170 G à 340 G garantit une faible magnétisation. Une cathode chaude injecte un fort courant thermionique à l’autre extrémité de la colonne de plasma. Les mesures optiques de température de la cathode ont révélé un profil fortement inhomogène dû aux interactions plasma-cathode, et fut reproduit numériquement avec succès par un modèle thermique détaillé. Le régime opératoire prédit est en excellent accord avec les expériences. L’influence expérimentale de l’injection d’électrons sur les propriétés plasmas, et plus particulièrement le potentiel plasma, a été couplée à une approche analytique basée sur un modèle de plasma magnétisé. Un accord qualitatif entre les prédictions théoriques et le contrôle effectif du potentiel plasma a été trouvé. La perspective de l’utilisation d’une cathode émissive comme nouveau paramètre de contrôle ouvre la possibilité d’un réglage fin de la dynamique globale du plasma, ainsi que la mitigation du transport et des instabilités au sein du plasma. Des améliorations sont discutées en vue d’une prédiction quantitative accrue. Enfin, une source de plasma hélicon haute densité a été implémentée afin d’atteindre des taux d’ionisation importants et un couplage antenne-plasma optimal. Ce nouveau système a été caractérisé à l’aide de sondes et d’imagerie rapide. Des signatures typiques des plasmas hélicons ont été retrouvées telles que des transitions de mode E-H-W, une rupture de symétrie liée au champ magnétique et la propagation d’ondes whistler m = +1. En outre, des oscillations basse-fréquence telles que des oscillations H-W et W-W, et des instabilités coexistantes de Rayleigh-Taylor et Kelvin-Helmholtz ont été identifiées. Une forte instabilité multi-échelles à 1080 G a été également brièvement explorée. L’identification des mécanismes d’instabilité via le calcul des taux de croissance, la décomposition 2D-FT et POD ont permis de comprendre les mécanismes physiques à l’oeuvre
Radial transport, azimuthal waves and instabilities are common features in magnetised plasmas, causing major challenges for plasma propulsion, plasma wakefield particle acceleration or fusion devices. Plasma properties control is desirable yet complex. This PhD thesis follows two goals, one being the use of an emissive cathode as a new parameter control and the other being the fundamental understanding of the helicon plasma operational stability. Firstly, the role of the injection of electrons inside a magnetised plasma column has been studied experimentally and numerically. The experimental set-up is a 80 cm long and 20 cm diameter vacuum vessel connected to a 11 cm wide glass tube. The argon gas at a base pressure of 0.13 Pa is ionised by a 3-turns inductive radio-frequency antenna supplied at 1 kW. Magnetic field ranging from 170 G to 340 G, ensures a weak magnetisation of the plasma. A large tungsten hot cathode was placed at the end of the plasma column to inject an important thermionic current. Electrical and optical measurements of the cathode temperature revealed a highly inhomogeneous cathode temperature profile due to plasma–cathode interactions. A detailed thermal modelling solved numerically accurately reproduces the heterogeneous rise in temperature witnessed experimentally. The operating regime was predicted in excellent agreement with experimental results.The fine understanding of the emissive cathode behaviour in presence of a surrounding magnetised plasma permitted to explore its influence on the plasma properties, and especially the plasma potential. An analytical approach based on a two-fluids plasma model and anisotropic electrical conductivities, predicting plasma potential control and plasma rotation regulation as a function of thermionic emission, has been applied and compared to a wide experimental dataset of plasma properties. The works presented confront the role of cross-field ion transport to experimental radial plasma potential scans with a semi-quantitative agreement, highlighting a new major application of emissive cathodes.Finally, a state-of-the-art helicon plasma source has been implemented to produce higher ionization rates. This new system required a complete characterisation of plasma properties through electrostatic probes and high-speed camera imaging. It reproduced well-known helicon plasma features such as E-H-W mode transitions, bistability and hysteresis, chirality emerging from the external magnetic field direction and the propagation of m = +1 whistler waves. Besides, it displayed complex behaviours such as H-W and W-W oscillations, or coexisting low-frequency Kelvin-Helmholtz and Rayleigh-Taylor instabilities. A strong multiscale core instability at 1080 G was also briefly investigated. Wave-mode identification based on theoretical growth rates, 2DFT modal decomposition and POD has been conducted, unravelling the physical mechanisms at stake
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Taillefer, Zachary R. "Characterization of the Near Plume Region of Hexaboride and Barium Oxide Hollow Cathodes operating on Xenon and Iodine." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/44.

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The use of electric propulsion for spacecraft primary propulsion, attitude control and station-keeping is ever-increasing as the technology matures and is qualified for flight. In addition, alternative propellants are under investigation, which have the potential to offer systems-level benefits that can enable particular classes of missions. Condensable propellants, particularly iodine, have the potential to significantly reduce the propellant storage system volume and mass. Some of the most widely used electric thrusters are electrostatic thrusters, which require a thermionic hollow cathode electron source to ionize the propellant for the main discharge and for beam neutralization. Failure of the hollow cathode, which often needs to operate for thousands of hours, is one of the main life-limiting factors of an electrostatic propulsion system. Common failure modes for hollow cathodes include poisoning or evaporation of the thermionic emitter material and erosion of electrodes due to sputtering. The mechanism responsible for the high energy ion production resulting in sputtering is not well understood, nor is the compatibility of traditional thermionic hollow cathodes with alternative propellants such as iodine. This work uses both an emissive probe and Langmuir probe to characterize the near-plume of several hollow cathodes operating on both xenon and iodine by measuring the plasma potential, plasma density, electron temperature and electron energy distribution function (EEDF). Using the EEDF the reaction rate coefficients for relevant collisional processes are calculated. A low current (< 5 A discharge current) hollow cathode with two different hexaboride emitters, lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6), was operated on xenon propellant. The plasma potential, plasma density, electron temperature, EEDF and reaction rate coefficients were measured for both hexaboride emitter materials at a single cathode orifice diameter. The time-resolved plasma potential measurements showed low frequency oscillations (<100 kHz) of the plasma potential at low cathode flow rates (<4 SCCM) and spot mode operation between approximately 5 SCCM and 7 SCCM. The CeB6 and LaB6 emitters behave similarly in terms of discharge power (keeper and anode voltage) and plasma potential, based on results from a cathode with a 0.020�-diameter. Both emitters show almost identical operating conditions corresponding to the spot mode regime, reaction rates, as well as mean and RMS plasma potentials for the 0.020� orifice diameter at a flow rate of 6 SCCM and the same discharge current. The near-keeper region plasma was also characterized for several cathode orifice diameters using the CeB6 emitter over a range of propellant flow rates. The spot-plume mode transition appears to occur at lower flow rates as orifice size is increased, but has a minimum flow rate for stable operation. For two orifice diameters, the EEDF was measured in the near-plume region and reaction rate coefficients calculated for several electron- driven collisional processes. For the cathode with the larger orifice diameter (0.040�), the EEDFs show higher electron temperatures and drift velocities. The data for these cathodes also show lower reaction rate coefficients for specific electron transitions and ionization. To investigate the compatibility of a traditional thermionic emitter with iodine propellant, a low-power barium oxide (BaO) cathode was operated on xenon and iodine propellants. This required the construction and demonstration of a low flow rate iodine feed system. The cathode operating conditions are reported for both propellants. The emitter surface was inspected using a scanning electron microscope after various exposures to xenon and iodine propellants. The results of the inspection of the emitter surface are presented. Another low current (< 5 A), BaO hollow cathode was operated on xenon and iodine propellants. Its discharge current and voltage, and plume properties are reported for xenon and iodine with the cathode at similar operating conditions for each. The overall performance of the BaO cathode on iodine was comparable to xenon. The cathode operating on iodine required slightly higher power for ignition and discharge maintenance compared to xenon, as evident by the higher keeper and anode potentials. Plasma properties in the near- plume region were measured using an emissive probe and single Langmuir probe. For both propellants, the plasma density, electron energy distribution function (EEDF), electron temperature, select reaction rate coefficients and time-resolved plasma potentials are reported. For both propellants the cathode operated the same keeper (0.25 A) and discharge current (3.1 A), but the keeper and anode potentials were higher with iodine; 27 V and 51 V for xenon, and 30 V and 65 V for iodine, respectively. For xenon, the mean electron energy and electron temperature were 7.5 eV and 0.7 eV, with bulk drift energy of 6.6 eV. For iodine, the mean electron energy and electron temperature were 6.3 eV and 1.3 eV, with a bulk drift energy of 4.2 eV. A literature review of relevant collisional processes and associated cross sections for an iodine plasma is also presented.
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Popov, M. Yu, A. P. Volkov, S. G. Buga, V. S. Bormashov, K. V. Kondrashov, R. L. Lomakin, N. V. Lyparev, V. V. Medvedev, S. A. Tarelkin, and S. A. Perfilov. "Nanostructured metal-fullerene field emission cathode." Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20585.

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One of the important properties of carbon nanostructures is their cold electron emission ability. Carbon nanotubes and other nanostructures are capable of emitting high currents at relatively low electrical fields. They are already used in functional devices such as field emitters. The conventional method of carbon nanostructured cathodes manufacturing is thin film nanocarbon deposition using CVD process on electrically conducting substrate like metal or doped silicon plates. The alternative way of manufacturing of carbon field emission cathodes is based on a special processing of carbon microfibers or composite materials in metal holders. We used the similar approach to produce composite metal-nanocarbon material which may be easily processed and shaped to produce an effective field emission cathode which can be easily fixed an any environment. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20585
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Vaughn, Joel M. "Thermionic Electron Emission Microscopy Studies of Barium and Scandium Oxides on Tungsten." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1279814656.

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Lee, Kon Jiun. "Current limiting of field emitter array cathodes." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19629.

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Shen, Xiangqian. "Novel processing routes for oxide cathode emission materials." Thesis, Loughborough University, 2000. https://dspace.lboro.ac.uk/2134/10822.

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An investigation has been carried out into the production of the alkaline earth carbonate and oxide powders and coatings suitable as cathode emission materials by the ethylenediaminetetraacetic acid (EDT A) gel method for potential application as cathode emission materials. The emission performance of thermionic cathodes coated with these materials has been measured, and found to give encouraging results, comparable with conventionally prepared oxide emission materials, despite the former having not been optimised. Amorphous gels of composition Ca-EDTA, Sr-EDTA, Ba-EDTA, [SrO.5 Bao.5J-EDTA and [SrO.5 Bao.5 Cao.05J-EDTA were successfully prepared from aqueous solutions of alkaline earth nitrates and EDT A. Subsequently, the thermal decomposition of the gels and the effects of temperature and atmospheres on the decomposition have been studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The gels and the powders derived from calcination of these gels at different temperatures have been characterised by Fourier transform infrared spectroscopy (FTIR) , X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) with X-ray energy dispersive (EDX) spectroscopy. Coatings prepared by dip-coating, spraying and electrophoretic deposition (EPD) from the EDT A-sols have been characterised by FTIR, XRI> and SEM techniques. In addition, an attempt was made to study the coating of the colloidal particles in the suspension of methanolethanediol- EDTA sol by electrochemical impedance spectroscopy.
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Mollart, T. P. "Electron emission processes in cold cathode thermal arcs." Thesis, Durham University, 1993. http://etheses.dur.ac.uk/5546/.

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In this Thesis the processes of electron emission from cathode electrodes are studied theoretically, and the applicability of these mechanisms to the non refractory cathodes that can be used to sustain thermal arcs was examined. Apparatus that was used to generate and manipulate thermal arcs along rail electrodes is described in this thesis. Techniques for driving arcs over polished sample electrodes with magnetic or aerodynamic forces are outlined. Scanning electron microscopy was used to study emission site formation on highly polished electrodes with a natural 2.5 nm oxide layer. Theoretical maximum electron current densities that can be extracted by the arc were calculated and these were used, in conjunction with information from the experimental work, to make estimates of the lifetime of emission spots that are seen on the cathode electrodes of thermal arc devices. The lifetime was found to be dependent on the arc velocity over a range of velocity values from 3 to 80 ms(^-1). The lifetime measured ranged from 2.4 µs to 0.024 µs. Experiments on arcs driven at a constant velocity using a combination of aerodynamic and magnetic forces showed that the formation of emission spots was independent of die applied external magnetic field. The presence of artificially grown copper (11) oxide layers, 50 nm and 100 nm thick, were found to influence the lifetime. The effect of the oxide layer was predicted using a simple model accounting for the change of resistance that such an oxide layer would be expected to cause. Additional experiments showed that the resistance of the arc was independent of the oxide layer thickness, as predicted by the model.
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Jones, Randolph D. "Circuit model of a low-voltage field emission cathode." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/15631.

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Books on the topic "Emissive cathode"

1

Kapustin, Vladimir, and Illarion Li. Theory, electronic structure and physical chemistry of materials cathodes for microwave devices. ru: INFRA-M Academic Publishing LLC., 2020. http://dx.doi.org/10.12737/1041298.

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In the monograph the kinetic theory of cathode materials based on metal and oxide phases, analytical methods of research of the cathodes, methods of study of their emission properties. Details the authors discuss the theory and physico-chemistry of oxide-Nickel, metalloplastic, and metal alloyed oxide-yttrium cathodes, including a cathode for magnetrons with cold start. Designed for scientific and engineering-technical workers, specializing in electronic materials and electronic devices.
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Kapustin, Vladimir, Aleksandr Sigov, Illarion Li, and Vladimir Mel'nikov. Point defects in oxides and emission properties. ru: INFRA-M Academic Publishing LLC., 2022. http://dx.doi.org/10.12737/1846464.

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The monograph discusses the influence of point defects in oxides, which are the main emission component of cathodes of electrovacuum microwave devices, on their emission properties. The theory of electron emission of oxides, analytical methods for studying cathodes, methods for studying their emission properties are described. The issues of the theory and physicochemistry of nickel-oxide, metal-porous, metal-alloy and yttrium oxide cathodes, including cathodes for cold-start magnetrons, are considered in detail. It is intended for scientific and engineering workers specializing in the field of electronic materials science and electronic devices. It can also serve as a textbook useful for teachers, graduate students, undergraduates, undergraduates of the corresponding physical-technical and natural-scientific specialties.
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Danilov, Vladimir, Roman Gaydukov, and Vadim Kretov. Mathematical Modeling of Emission in Small-Size Cathode. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-0195-1.

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S, MacRae Gregory, and United States. National Aeronautics and Space Administration., eds. Requirements for long-life operation of inert gas hollow cathodes--preliminary report. [Washington, DC: National Aeronautics and Space Administration, 1990.

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S, MacRae Gregory, and United States. National Aeronautics and Space Administration., eds. Requirements for long-life operation of inert gas hollow cathodes--preliminary report. [Washington, DC: National Aeronautics and Space Administration, 1990.

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S, MacRae Gregory, and United States. National Aeronautics and Space Administration., eds. Requirements for long-life operation of inert gas hollow cathodes--preliminary report. [Washington, DC: National Aeronautics and Space Administration, 1990.

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Gordeev, V. F. Termoėmissionnye dugovye katody. Moskva: Ėnergoatomizdat, 1988.

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Mesi︠a︡t︠s︡, G. A. Explosive electron emission. Ekaterinburg: URO-Press, 1998.

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Center, NASA Glenn Research, ed. Ferroelectric emission cathodes for low-power electric propulsion. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 2002.

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Bajic, Stevan. "Non-metallic" cold-cathode electron emission from composite metal-insulator microstructures. Birmingham: AstonUniversity. Department of Electrical and Electronic Engineering and Applied Physics., 1989.

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Book chapters on the topic "Emissive cathode"

1

Egorov, Nikolay, and Evgeny Sheshin. "Field Emission Cathodes." In Field Emission Electronics, 229–93. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56561-3_5.

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Egorov, Nikolay, and Evgeny Sheshin. "Field Emission Cathode-Based Devices and Equipment." In Field Emission Electronics, 427–538. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56561-3_8.

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Egorov, Nikolay, and Evgeny Sheshin. "Carbon-Based Field-Emission Cathodes." In Field Emission Electronics, 295–367. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56561-3_6.

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Egorov, Nikolay, and Evgeny Sheshin. "Computation of Field-Emission Cathode-Based Electron Guns." In Field Emission Electronics, 369–426. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56561-3_7.

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Egorov, Nikolay, and Evgeny Sheshin. "Simulation of Structure and Parameters of Field Emission Cathodes." In Field Emission Electronics, 171–228. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-56561-3_4.

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Ohkawa, Yasushi. "CNT Field-Emission Cathode for Space Applications." In Nanostructured Carbon Electron Emitters and Their Applications, 315–30. New York: Jenny Stanford Publishing, 2021. http://dx.doi.org/10.1201/9781003141990-15.

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Mesyats, Gennady A., and Dimitri I. Proskurovsky. "Formation of New Emission Centers on the Cathode." In Pulsed Electrical Discharge in Vacuum, 159–80. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-83698-5_8.

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Baumann, Peter K., and Robert J. Nemanich. "Electron Emission from CVD-Diamond Cold Cathodes." In Low-Pressure Synthetic Diamond, 281–303. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-71992-9_15.

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Fursey, Georgiy N. "Explosive Electron Emission of Carbon-Based Cathodes, and Applications." In Modern Developments in Vacuum Electron Sources, 529–46. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-47291-7_11.

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Lv, Wenmei, Lian Wang, Yiwei Lu, Dong Wang, Hui Wang, Yuxin Hao, Yuanpeng Zhang, Zeqi Sun, and Yongliang Tang. "Field Emission Properties of Wrinkled Multi-layer Graphene Cathodes." In Springer Proceedings in Physics, 280–84. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-3913-4_54.

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Conference papers on the topic "Emissive cathode"

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Wang, L. "Research on Pulsed High-Current Secondary Electron Emission Cathode." In 2024 IEEE International Conference on Plasma Science (ICOPS), 1. IEEE, 2024. http://dx.doi.org/10.1109/icops58192.2024.10627566.

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Lin, Ming-Wei, Chin-Hsin Yeh, Ten-Chin Wen, and Tzung-Fang Guo. "Blue-emissive polymer light-emitting diodes through anode/cathode interfacial modification." In SPIE Organic Photonics + Electronics, edited by Franky So and Chihaya Adachi. SPIE, 2012. http://dx.doi.org/10.1117/12.929449.

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Gallardo, Juan, Eduardo Ahedo, and Manuel Martinez-Sanchez. "Effects of an Intermediate Emissive Cathode on the Hall Thruster Discharge." In 38th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2002. http://dx.doi.org/10.2514/6.2002-4112.

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Litvinov, E., M. Yalandin, V. Shpak, S. Rukin, G. Mesyats, S. Korovin, and V. Rostov. "Special Features of Emissive Characteristics of Cold Graphite Cathode with an Increase in the Repetition Rate of Nanosecond Accelerating Pulses." In 2005 IEEE Pulsed Power Conference. IEEE, 2005. http://dx.doi.org/10.1109/ppc.2005.300505.

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Udhiarto, Arief, Layina Maula Haryanto, Bobi Khoerun, and Djoko Hartanto. "Effect of anode and cathode workfunction on the operating voltage and luminance of a single emissive layer organic light emitting diode." In 2017 15th International Conference on Quality in Research (QiR): International Symposium on Electrical and Computer Engineering. IEEE, 2017. http://dx.doi.org/10.1109/qir.2017.8168453.

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Scheeline, Alexander, and M. A. Lovik. "Light scattering from particulates in high voltage sparks." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.tha9.

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The high-voltage atmospheric-pressure spark is commonly used for elemental analysis of alloys. Emission from atoms vaporized from the cathode is used for determining composition of the cathode. Particulates represent a sink for free atoms which might otherwise be useful for emission or absorption measurements of the cathode’s composition. Condensation kinetics are not well understood, nor are free atom lifetimes known. Mie scattering can be used to monitor particulates in situ, but polarization of incident laser light must be controlled if size information is to be recovered from the scattered light. Although work to date has used a He–Ne laser, work at 416 nm (He–Cd laser) or bluer wavelengths would substantially improve signal-to-noise ratio and would also reduce the minimum detectable particle size. We report appartus for controlling ellipticity and major axis orientation of incident laser light. The approach used does not require ideal wave plates or ideal mirrors to be used. Observations or particulates produced when sparking to aluminum cathodes will also be reported. Particulate size, spatial distribution, and trajectories are discussed.
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Marrese-Reading, Colleen, Bill Mackie, Jay Polk, and Kevin Jensen. "Field emission cathodes for electrodynamic tethers: Identifying compatible cathode materials." In SPACE TECHNOLOGY AND APPLICATIONS INTERNATIONAL FORUM- STAIF 2002. AIP, 2002. http://dx.doi.org/10.1063/1.1449748.

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Rand, Lauren P., Ryne M. Waggoner, and John D. Williams. "Hollow Cathode With Low Work Function Electride Insert." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-65785.

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Hollow cathodes are critical devices in the successful operation of electric propulsion thrusters. Cathodes featuring C12A7:electride as an ultra-low work function thermionic emitter are hypothesized to have faster start-up times and lower operating temperatures than conventional hollow cathodes. C12A7:electride is a crystalline ceramic in which electrons clathrated in sub-nanometer sized cages act as a conductive medium. Due to its unique atomic structure and large size, C12A7:electride has a predicted work function of 0.6 eV. As a result, C12A7:electride is an attractive option for a thermionic emission material in a hollow cathode. Calculations predict equivalent levels of current emission as LaB6 or CeB6, but at much lower temperature. C12A7:electride is stable at temperatures below its re-crystallization temperature (∼1000 °C) and is not consumed during operation. C12A7:electride has been fabricated at CSU using a simplified, one-step approach that results in a more conductive material than previously reported. The material has been integrated into a novel hollow cathode design that takes advantage of its unique properties to decrease start-up time and power consumption. Our paper will discuss preliminary results obtained with several cathode configurations. In addition, results from the experimental determination of basic material properties such as conductivity and work function will be presented. Strategies to further enhance electron emission through surface modifications will also be discussed.
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Koval, N. N., V. N. Devyatkov, and M. S. Vorobyev. "GRID PLASMA CATHODES: HISTORY, CONDITION, PROSPECTS." In Plasma emission electronics. Buryat Scientific Center of SB RAS Press, 2023. http://dx.doi.org/10.31554/978-5-7925-0655-8-2023-34-41.

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Astrelin, V. T. "INFLUENCE OF ELECTRON BEAM SOURCE PARAMETERS ON ELECTRON EMISSION FROM PLASMA CATHODE." In Plasma emission electronics. Buryat Scientific Center of SB RAS Press, 2023. http://dx.doi.org/10.31554/978-5-7925-0655-8-2023-56-63.

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Reports on the topic "Emissive cathode"

1

Lee, Bo. A knife-edge array field emission cathode. Office of Scientific and Technical Information (OSTI), August 1994. http://dx.doi.org/10.2172/515571.

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Thangaraj, Charles. Gated Field-Emission Cathode Radio-Frequency (RF) Gun. Office of Scientific and Technical Information (OSTI), November 2016. http://dx.doi.org/10.2172/1433861.

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Sampayan, S. E., G. J. Caporaso, C. L. Holmes, E. J. Lauer, D. Prosnitz, D. O. Trimble, and G. A. Westenskow. Emission from ferroelectric cathodes. Revision 1. Office of Scientific and Technical Information (OSTI), May 1993. http://dx.doi.org/10.2172/10124125.

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Ohlinger, Wayne L., and D. N. Hill. Field Emission Cathode and Vacuum Microelectronic Microwave Amplifier Development. Fort Belvoir, VA: Defense Technical Information Center, March 1992. http://dx.doi.org/10.21236/ada253846.

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Ohlinger, Wayne L., and D. N. Hill. Field Emission Cathode and Vacuum Microelectronic Microwave Amplifier Development. Fort Belvoir, VA: Defense Technical Information Center, March 1992. http://dx.doi.org/10.21236/ada253847.

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Jay L. Hirshfield. Rf Gun with High-Current Density Field Emission Cathode. Office of Scientific and Technical Information (OSTI), December 2005. http://dx.doi.org/10.2172/861455.

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Rocca, J. J., B. Szapiro, and C. Murray. Electron Beam Generation by Electron Bombardment Induced Cathode Emission. Fort Belvoir, VA: Defense Technical Information Center, July 1989. http://dx.doi.org/10.21236/ada218203.

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Melton, C., N. Pogue, and T. Watson. 1013209497 - Cathode Side-emission Mitigation for Linear Induction Accelerators (AA). Office of Scientific and Technical Information (OSTI), July 2023. http://dx.doi.org/10.2172/1988208.

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Gundersen, Martin. Pulsed Power Plasma Devices Based on Hollow and Super-Emissive Cathodes. Fort Belvoir, VA: Defense Technical Information Center, October 1995. http://dx.doi.org/10.21236/ada303960.

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Hirshfield, Jay L. HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION. Office of Scientific and Technical Information (OSTI), December 2012. http://dx.doi.org/10.2172/1058891.

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