Conferences related to Cathodes

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2021 IEEE Photovoltaic Specialists Conference (PVSC)

Photovoltaic materials, devices, systems and related science and technology


2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe)

Energy conversion and conditioning technologies, power electronics, adjustable speed drives and their applications, power electronics for smarter grid, energy efficiency,technologies for sustainable energy systems, converters and power supplies


2020 IEEE 21st International Conference on Vacuum Electronics (IVEC)

Technical presentations will range from the fundamental physics of electron emission and modulated electron beams to the design and operation of devices at UHF to THz frequencies, theory and computational tool development, active and passive components, systems, and supporting technologies.System developers will find that IVEC provides a unique snapshot of the current state-of-the-art in vacuum electron devices. These devices continue to provide unmatched power and performance for advanced electromagnetic systems, particularly in the challenging frequency regimes of millimeter-wave and THz electronics.Plenary talks will provide insights into the history, the broad spectrum of fundamental physics, the scientific issues, and the technological applications driving the current directions in vacuum electronics research.


2020 IEEE International Conference on Image Processing (ICIP)

The International Conference on Image Processing (ICIP), sponsored by the IEEE SignalProcessing Society, is the premier forum for the presentation of technological advances andresearch results in the fields of theoretical, experimental, and applied image and videoprocessing. ICIP 2020, the 27th in the series that has been held annually since 1994, bringstogether leading engineers and scientists in image and video processing from around the world.


2020 IEEE International Conference on Plasma Science (ICOPS)

IEEE International Conference on Plasma Science (ICOPS) is an annual conference coordinated by the Plasma Science and Application Committee (PSAC) of the IEEE Nuclear & Plasma Sciences Society.


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Periodicals related to Cathodes

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Aerospace and Electronic Systems Magazine, IEEE

The IEEE Aerospace and Electronic Systems Magazine publishes articles concerned with the various aspects of systems for space, air, ocean, or ground environments.


Antennas and Propagation, IEEE Transactions on

Experimental and theoretical advances in antennas including design and development, and in the propagation of electromagnetic waves including scattering, diffraction and interaction with continuous media; and applications pertinent to antennas and propagation, such as remote sensing, applied optics, and millimeter and submillimeter wave techniques.


Biomedical Engineering, IEEE Transactions on

Broad coverage of concepts and methods of the physical and engineering sciences applied in biology and medicine, ranging from formalized mathematical theory through experimental science and technological development to practical clinical applications.


Components and Packaging Technologies, IEEE Transactions on

Component parts, hybrid microelectronics, materials, packaging techniques, and manufacturing technology.


Computer Graphics and Applications, IEEE

IEEE Computer Graphics and Applications (CG&A) bridges the theory and practice of computer graphics. From specific algorithms to full system implementations, CG&A offers a strong combination of peer-reviewed feature articles and refereed departments, including news and product announcements. Special Applications sidebars relate research stories to commercial development. Cover stories focus on creative applications of the technology by an artist or ...


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Most published Xplore authors for Cathodes

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Xplore Articles related to Cathodes

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Recent Developments in Scandia-Doped Dispenser Cathodes

2006 IEEE International Vacuum Electronics Conference held Jointly with 2006 IEEE International Vacuum Electron Sources, 2006

We measured SDDCs emission property and made comparison with impregnated scandate (I-Sc). A reasonable explanation on abnormal Schottky effect of SDDCs is given. The authors proposed a "semiconductor-monolayer superposition" model to explain emission mechanism of all kinds of thermionic cathodes, including oxide cathodes, M-type cathodes and scandate cathodes. Finally, from the view of engineering application, some improvement ideas and suggestions ...


Influence of the dispenser cathodes surface structure on their emission parameters

2009 IEEE International Vacuum Electronics Conference, 2009

The present paper provides AFM investigations of the surface of dispenser cathodes with osmium film and scandate cathodes. In order to explain high emission properties of these cathodes we used phenomenon of thermo-field electron emission.


Study of the critical issues in the assembly of cold cathodes in electron gun for vacuum tube

2013 6th UK, Europe, China Millimeter Waves and THz Technology Workshop (UCMMT), 2013

In this work we present the realization of compact electron sources realized with carbon nanotubes (CNTs) cathodes. The main scope of this study is the description of the critical in the integration of CNTs cathodes in electron guns.


Emission uniformity and emittance of explosive field-emission cathodes

IEEE Transactions on Plasma Science, 2002

Explosive field-emission cathodes as well as plasma-flashover cathodes are important for high-power microwave tubes. These cathodes have the advantage of being lightweight as well as requiring no heater for electron emission. However, this class typically suffers from large amounts of outgassing, nonuniform emission, and very high emittance. In this paper, we review research into the uniformity and emittance of tufted ...


Investigation on robustness of Nanosized-Scandia Doped Dispenser Cathodes

2016 IEEE International Vacuum Electronics Conference (IVEC), 2016

In order for practical applications in Vacuum Electron Devices (VEDs), the robustness of Scandia Doped Dispenser (SDD) cathodes has been widely concerned. Machinability, emission performance from machined surface, recovery of emission after poisoning; air exposure and ion bombardment have, thereby, been studied. The investigation demonstrated that the cathodes can be successfully machined by normal lathing to the required diameters and ...


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IEEE.tv Videos

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IEEE-USA E-Books

  • Recent Developments in Scandia-Doped Dispenser Cathodes

    We measured SDDCs emission property and made comparison with impregnated scandate (I-Sc). A reasonable explanation on abnormal Schottky effect of SDDCs is given. The authors proposed a "semiconductor-monolayer superposition" model to explain emission mechanism of all kinds of thermionic cathodes, including oxide cathodes, M-type cathodes and scandate cathodes. Finally, from the view of engineering application, some improvement ideas and suggestions to future work of SDDCs are given

  • Influence of the dispenser cathodes surface structure on their emission parameters

    The present paper provides AFM investigations of the surface of dispenser cathodes with osmium film and scandate cathodes. In order to explain high emission properties of these cathodes we used phenomenon of thermo-field electron emission.

  • Study of the critical issues in the assembly of cold cathodes in electron gun for vacuum tube

    In this work we present the realization of compact electron sources realized with carbon nanotubes (CNTs) cathodes. The main scope of this study is the description of the critical in the integration of CNTs cathodes in electron guns.

  • Emission uniformity and emittance of explosive field-emission cathodes

    Explosive field-emission cathodes as well as plasma-flashover cathodes are important for high-power microwave tubes. These cathodes have the advantage of being lightweight as well as requiring no heater for electron emission. However, this class typically suffers from large amounts of outgassing, nonuniform emission, and very high emittance. In this paper, we review research into the uniformity and emittance of tufted carbon-fiber cathodes that have been coated with cesium iodide (CsI) salt. The CsI cathode is compared to polymer velvet, metal-dielectric, and carbon-slat cathodes. We find the uniformity and emittance are related for all of these cathodes. In general, the more uniform the electron emission, the lower the emittance of the cathode. This article shows that given proper diode design, the tufted carbon-fiber cathode with CsI has some promise as an electron emitter producing a good quality electron beam.

  • Investigation on robustness of Nanosized-Scandia Doped Dispenser Cathodes

    In order for practical applications in Vacuum Electron Devices (VEDs), the robustness of Scandia Doped Dispenser (SDD) cathodes has been widely concerned. Machinability, emission performance from machined surface, recovery of emission after poisoning; air exposure and ion bombardment have, thereby, been studied. The investigation demonstrated that the cathodes can be successfully machined by normal lathing to the required diameters and curvature radius. A life test with DC loads of up to 40 A/cm2at 970 °Cbhas been completed more than 5000 hours to date for a cathode with machined surface. A full restoring of emission has been proved after the cathodes were exposed to air and reactivated for a short time. This performance allows the cathodes to be pre-heated before assembling into the electron guns. Poisoning experiment evinces that in comparison with that of a 311-XM cathode, which was reported to be less affected by gas poisoning than other M cathode, the poisoning thresholds of residual gases for the SDD cathodes are more than one order of magnitude higher at equivalent temperatures but with higher emission level. The emission and surface behaviour, when an activated cathode encounters ion bombardment at its operating condition, has also been investigated and discussed.

  • Recent progresses on nanosized-scandia-doped dispenser cathodes

    In this paper, the recent progresses on nanosized-scandia-doped impregnated (SDI) dispenser cathodes made in this research group are reviewed. Spray- drying process, a new method for nonosized-scandia-doped tungsten powder preparation, has been developed. Compared with the formerly used sol-gel technique, the new method results in more controls over the tungsten grain size and morphology. Similar emission level can be reached for the cathodes made from this kind of powder to that of made by sol-gel process. Continuously pulsed emission life test at about 50 A/cm2has been carried out in a Pierce- gun open structure tube at e beam inc., USA and has been steady for nearly the entire period of 1000 hours. A knee temperature as low as 900 °CB-Mofor initial current density of 58 A/cm2was estimated from the Miram curve. DC emission has been evaluated in a closely-spaced diode system with water-cooled copper anode. Over 60 A/cm2space charge limited (SCL) DC current density was repeatedly measured at 950 °CB-Mo. Below this level the DC and pulsed emission are agree well. In DC life test at 950 °CB-Mo, an initial current density of 20 A/cm2rose gradually to about 30 A/cm2during first several hundred hours then remained stably for more than 2000 hours. The increase in emission capability has also be verified by a comparison of I/V characters at beginning and 1000 hours of the life test. The improvement of emission performance for SDI cathodes has been correlated to the surface composition changes during life which was performed by in situ surface analysis.

  • A study of tungstate formation in dispenser cathodes

    L-3 Communications ETI has been involved in the manufacture of Vacuum Electron Devices (VEDs) for over 50 years. The cathode is a critical component of the VED and L-3 ETI has developed in-house facilities for the research, development, manufacture, and test of the Space TWT cathode [1, 2]. In addition to cathodes used in VEDs, the Electric Propulsion Product Line at L-3 ETI uses hollow dispenser cathodes. In this area as well, L-3 ETI has invested resources in research and test. The performance of the M-coated dispenser cathode over time depends primarily on the diffusion of the M-coat layer and the depletion of barium. For the hollow cathode, the depletion of barium is considered the primary life-limiting factor. The depletion of barium is dominated by evaporation but the chemical reactions that occur inside the dispenser pellet can produce barium tungstates that effectively prevent the barium from migrating to the surface. This presentation examines the role of barium tungstate formation on the life of the cathode.

  • Studies on Tungsten-Rhenium mixed matrix cathodes

    Studies are carried out on W-Re mixed matrix cathodes of varying compositions. The work function, when W & Re are in close proportions, is close to that of Re-coated cathode. The cathodes exhibited heating and decay effects at long pulses. AES in conjunction with SEM studies supported the presence of a thick active layer. The non-metallic behaviour is attributed to the presence of an appreciable amount of unreduced BaO. The resistance to Oxygen poisoning is better than that of a conventional B-Type cathode.

  • Performance of field emission cathodes in xenon environments

    Summary form only given, as follows. Field emission (FE) cathodes are currently being considered to supply electrons in electric propulsion systems for propellant ionization and ion beam neutralization. Hollow cathodes with thermionic electron emitters typically used with Hall and ion thrusters require propellant and heaters for operation. Therefore there are lower limits on their size and power. Because FE cathodes do not require propellant or heaters they can be used with small and micropropulsion systems. The primary concern with integrating these two technologies is cathode lifetime. An FE cathode must be capable of operation in a plasma environment where xenon pressures exceed 2/spl times/10/sup -6/ Torr. Experiments were conducted at the Jet Propulsion Laboratory to evaluate the performance of silicon and molybdenum microtip field emission array cathodes, and carbon film cathodes in xenon pressures up to 2/spl times/10/sup -5/ Torr. Experimental and modeling results were used to determine energy thresholds for sputtering silicon and molybdenum by xenon ions.

  • Time and Energy-resolved Average Ion Charge States in Pulsed Cathodic Vacuum Arc Plasmas of Nb-A1 Cathodes as a Function of Ar Pressure

    Despite substantial progress in the last decades, the physics responsible for the plasma properties of cathodic vacuum arcs are still a matter of dispute, particularly for multi-element cathodes. The plasma analysis is complicated by the generally occurring neutral background of metal atoms, which perturbs initial ion properties. By using a time-resolved method in combination with pulsed arcs and a Nb-Al cathode model system, we investigate the influence of cathode composition on ion properties, while making the influence of neutrals visible for the observed time frame. This model system consists out of two different Nb-Al compositions with the the atomic ratios 75/25 and 25/75, as well as pure Nb and Al cathodes. The results visualize average charge states of Nb and Al ions of 600 μs plasma pulses, extracted 0.27 m from the cathode, resolved in energy and time. In addition to high vacuum at a base pressure of 10-4Pa, results at three elevated Ar gas pressures (0.04 Pa, 0.20 Pa and 0.40 Pa) are shown. For high vacuum, ion properties were generally found to be strongly dependent on the cathode material, but deviating from a simple linear interpolation between the ion properties from Nb and Al cathodes. The influence of an inert background gas is analyzed by comparing these results with those at increased pressure, which show reduced ion charge states, up to a situation where mostly Nb2+and Al+ions are detected.



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