Description
posters session.
additional opportunity to discuss posters and more.
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Dr Richard Forbes (University of Surrey, UK)20/03/2017, 19:30Postersposter
When an individual post-like field emitter (modelled as standing on one of a pair of parallel planes) is sufficiently resistive, and current through it sufficiently large, then voltage loss occurs along it. This Poster shows this voltage loss is directly and inextricably linked to a reduction in the field enhancement factor (FEF) at the post apex. A formula relating apex-FEF reduction to this...
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Itzhak Beilis (Electrical Discharge and Plasma Laboratory, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University)20/03/2017, 19:30Postersposter
In a Vacuum Arc with a Black Body Assembly (VABBA), cathode material is
emitted into a closed chamber formed by the end surface of a water-cooled cylindrical
cathode and a cup shaped refractory anode that is heated by the arc. Material is eroded from
the cathode spots as plasma and MPs. They impinge on the hot anode and are re-evaporated
from it, forming a dense high-pressure...
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20/03/2017, 19:30Postersposter
Abstract: Electrical breakdowns and cathode spot initiation are important phenomena in applications used for components with high voltage assemblies. During the cathode spot formation, dense and hot plasma is produced that generates an intense heat flux towards to the cathode surface. As result the cathode melts. Under the plasma-surface interaction, droplets and craters are formed. The...
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20/03/2017, 19:30Postersposter
Cathodic Breakdown (BD) is a main failure mode of systems relying on maintaining high fields under vacuum.
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It has been suggested that field emission (FE) currents, known to exist in the system prior to breakdown, are linked to the BD process.
We report on observations of non-Gaussian fluctuations in FE currents measured in CERN DC setups and analyzed using a moving average filter. These... -
20/03/2017, 19:30Postersposter
Mechanisms behind breakdowns on copper surfaces have been studied with various methods using both experiments and simulations. The high-voltage direct current measurements with the Large Electrode System in CERN have been proven good in acquiring statistics on a large number of breakdown events. Recently, similar experiments have started at the University of Helsinki in order to provide...
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Dr SUSUMU KATO (National Institute of Advanced Industrial Science and Technology(AIST))20/03/2017, 19:30Postersposter
Many optical elements such as mirror, window, amplifier, and wavelength conversion elements are made from oxide materials. The elucidation of damage threshold and mechanism is indispensable to the development of high-power system. Especially, in high-repetition-rate system, the accumulation of defects such as color center causes the damage.
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In this work, we propose a kinetic model including... -
Prof. Ady Hershcovitch (BNL)20/03/2017, 19:30Postersposter
Certain adaptations of metal vapor vacuum arcs can be a promising approach as high charge state ion sources for various applications including relativistic heavy ion colliders, heavy ion inertial confinement fusion and with modifications to boron phosphorous as well as for As, and Sb ions for ion implantation for semiconductor manufacturing as well. Two approaches have shown good promise:...
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Dr Richard Forbes (University of Surrey, UK)20/03/2017, 19:30Postersposter
This note suggests improvements in presenting field electron emission (FE) theory. It relates to the so-called principal Schottky-Nordheim (SN) barrier function "v" used in Murphy-Good-type FE theory. I argue that: (1) we should separate the mathematics of v from its applications in tunnelling theory; (2) we need to change the independent variable used; and (3) we can improve the notation.
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It... -
Iaroslava Profatilova (Nat. Acad. Sci., Inst. Appl. Phys. (UA))20/03/2017, 19:30poster
For the development of high gradient accelerating structures of CLIC and other similar machines it is vital to understand the mechanism of vacuum breakdown. Previous investigations into the phenomena were performed through lengthy and costly RF conditioning of accelerating structures and cells. In an attempt to more efficiently investigate the effects of different materials and conditioning...
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Simon Vigonski (University of Tartu)20/03/2017, 19:30Postersposter
Surface defects are thought to play an important role in vacuum breakdowns. Possible nanoprotrusions can significantly enhance the electric field, leading to increased field emission, atom evaporation, and eventually arcing. Atomic scale simulations are very useful in studying dislocation behaviour and surface defects. However, the main material of interest, copper, is in practice covered by...
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Mr Zhipeng Zhou (Xi'an Jiaotong University)20/03/2017, 19:30Postersposter
In order to investigate the evolution of species type during a vacuum breakdown, a spectroscope with a ICCD was adopted to detect the spectrum during the breakdown, and the state of species can be deduced from the spectra. A tip-to-tip gap was installed in a vacuum chamber; the gap distance varied from 0.5 mm to 3 mm; and copper and tungsten were chosen as the cathode and anode material,...
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Dr Richard Forbes (University of Surrey, UK)20/03/2017, 19:30Postersposter
Fowler-Nordheim (FN) theory uses "smooth-surface" conceptual emitter models. It is not accurate theory because it disregards the existence of atoms, and takes the emitter surface charge as confined to an infinitesimally thin classical layer. Developing fully self-consistent field emission theory will be intensively difficult, and has received limited attention. It could take 50-100 years....
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