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Topic: Secondary emission

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Vacuum tube

	LEAN in the News
		Emissions from process vents may be released either directly to the atmosphere, downstream of a recovery system, or to a control device that is vented to the atmosphere.
		Emissions from transfer loading can be reduced by a variety of techniques, including the installation of a vapor balance system or a vapor collection system that would route the emissions to a control device.
		Emissions from these streams can be reduced by installing add-on control devices at the points of generation or by collecting wastewater for treatment through an enclosed collection system that is controlled for air emissions.
	www.leanweb.org /air/bid1c.html (15004 words)

	EPA: Federal Register: National Emission Standards for Hazardous Air Pollutants for Source Categories; National ...
		Emission tests were conducted at 12 facilities to measure uncontrolled and controlled emissions from selected production processes and to evaluate the effectiveness of the technology representative of the MACT floor level of control.
		Emissions test measurements show that these sources emit THC and D/F. Six of the 12 sweat furnaces are equipped with afterburners to control THC and D/F. The MACT floor, for categories of less than 30 sources is determined by the median of the five best controlled sources in the category.
		The achievable emissions limitation for group 1 furnace emission units and the standard for new and reconstructed group 1 furnaces is based on furnaces in which dirty charge materials and unlimited fluxing are used, and that are equipped with the MACT floor control technology, a fabric filter with a continuous lime injection system.
	www.epa.gov /fedrgstr/EPA-AIR/1999/February/Day-11/a1475.htm (13133 words)

	[No title]
		The first definition relates to emission, well outside in-band and for which the very low level is related to the "default" of the transmitter rather than to the useful signal.
		The status of unwanted emission limit is not so clear because secondary and primary radar are not always differentiated in ITU texts, and because the recent ITU work on the boundary between the spurious and the out-of-band domains has still confused the issue.
		Secondary mode S radars and associated services are seen now as the major surveillance facilities for world wide aviation.
	www.icao.int /anb/panels/acp/WG/F/WGF11/wgf11-13.doc (1026 words)

	Electron Emission
		Electron emission is actually the basic of tube working principal, it is defined as liberation of free electron from a surface of a substance caused by the externak energy transfered to the electrons.
		Electron emission from a metalic surface by the bombardment of high speed electrons or other particles is known as secondary emission.
		The effect of secondary emission are very undesirable in many electron device for example in tetrode where secondary emission is responsible for negative resistance.
	www.geocities.com /tube_theory/ElectronEmission.htm (984 words)

	define_secondary_emission
		We assume that the secondary emission yield is a function only of the incident particle's kinetic energy.
		The mean secondary yield is computed from the kinetic energy at the time of loss.
		The number of secondary particles emitted is chosen using a Poisson distribution with that mean.
	www.aps.anl.gov /asd/oag/manuals/spiffe_V3.2/node18.html (272 words)

	Secondary emission (from electron tube) -- Encyclopædia Britannica (Site not responding. Last check: 2007-10-09)
		The amount of secondary emission depends on the properties of the material and the energy and angle of…
		More results on "Secondary emission (from electron tube)" when you join.
		Before an alpha emission, the nucleus had a ratio of neutrons and protons which would usually hold it together against the whirlings of the alpha particles (or the particles which make them up).
	www.britannica.com /eb/article-236487 (887 words)

	Electronic Code of Federal Regulations:
		Secondary emissions means particulate matter emissions that are not captured by the BOPF primary control system, including emissions from hot metal transfer and skimming stations.
		The monitoring device or devices are to be placed at locations near each capture point of the secondary emission capture system to monitor the exhaust ventilation rates or levels adequately, or in alternative locations approved in advance by the Administrator.
		Following the compliance test, the owner or operator shall operate the secondary emission control system at exhaust ventilation rates or levels for each duct of the system that are no lower than 90 percent of the exhaust ventilation values established during the most recent compliance test.
	ecfr.gpoaccess.gov /cgi/t/text/text-idx?c=ecfr&sid=185bdc165a6c68b9a1df1bc3fa8e658c&rgn=div6&view=text&node=40:6.0.1.1.1.28&idno=40 (2184 words)

	Angular Distribution of Elastically Scattered Electrons and Effect on Collector Performance
		Secondary electrons are emitted with energies ranging from near zero to the energy of the incident primary.
		Lewis researchers discovered that elastically scattered electrons have a complex angular distribution that is strongly dependent on the atomic number and surface morphology of the target material, as well as the energy and angle of incidence of the primary beam.
		Although back-scattered secondaries dominate the distributions of the textured copper surface, the yield is substantially lower.
	www.lerc.nasa.gov /WWW/RT1998/5000/5620vaden.html (644 words)

	Secondary emission - Wikipedia, the free encyclopedia
		Generally, one electron gives rise to several secondary electrons.
		This effect can be undesirable such as in the tetrode thermionic valve (tube).
		In this instance the positively charged screen grid can accelerate the electron stream sufficiently to cause secondary emission at the anode (plate).
	en.wikipedia.org /wiki/Secondary_emission (340 words)

	Microchannel plate and a method for manufacturing the same - Patent 4780395
		Secondary electrons emitted from the emission surface are accelerated by voltage E2, applied between first and second electrodes 6a and 6b on two opposite sides of microchannel plate 4.
		Since the accelerating electrodes are formed by the lift-off method, moreover, their material cannot spoil the secondary electron-emission surface by sticking to the inside of the microchannels.
		According to the present invention, secondary electron-emission surface 23 is not limited to the aforementioned two-layer structure which includes the PbO and Cu.sub.2 O films.
	www.freepatentsonline.com /4780395.html (2410 words)

	[No title] (Site not responding. Last check: 2007-10-09)
		Each emission period, during which the Q-switch is off (open), is sufficiently long to allow the laser to emit a primary emission pulse and a plurality of secondary emission pulses, all of which impinge upon the workpiece.
		The intensities of these primary and secondary emission pulses are less than the intensity of the single emission pulse that would be emitted if the emission period were shorter and the repetition rate kept the same.
		These secondary pulses result from the fact that energy is continuously being pumped into energy storage rod 12 by diode pump 14.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=99/65123.991216&ELEMENT_SET=DECL (4400 words)

	[No title] (Site not responding. Last check: 2007-10-09)
		As a result of the variation in energy of impinging electrons, the secondary emission coefficient function of the wall will also vary significantly from the portion of the spacer structure near the cathode to the portion of the spacer structure near the anode.
		In this embodiment, the second coating material has a secondary electron emission coefficient function which is different than the secondary electron emission coefficient function of the spacer wall and which is also different than the secondary electron emission coefficient function of the first coating material.
		That is, in addition to tailoring the secondary electron emission coefficient function to a value of near 1.0 along the entire length thereof, spacer assembly 100 does not degrade severely when subjected to electron bombardment.
	www.wipo.int /cgi-pct/guest/getbykey5?KEY=00/51153.000831&ELEMENT_SET=DECL (5608 words)

	Apparatus for enhanced neutralization of positively charged ion beam - Patent 4463255
		This is electron emission stimulated by received electrons as compared with secondary electrons of the type produced by the implantation of ions into a target.
		The emitted secondary electrons are slow moving as compared to the primary electron beam and most have energies less than 100 ev and therefore have a significant capture cross-section in the field of the moving ion beam.
		To prevent the reflector from impeding the emission of primary electrons a bias voltage supply 22 keeps the reflector at a voltage at least as negative as the potential of the emitted electrons with respect to the Faraday cage 20 not to interfere with the emission of the beam.
	www.freepatentsonline.com /4463255.html (2881 words)

	[No title] (Site not responding. Last check: 2007-10-09)
		I was able to observe secondary emission on the 6AU6 without bias at 48 volts on the screen and up to 50 volts on the plate, as well as with 84 volts on the screen and up to 100 volts on the plate.
		I was also able to observe secondary emission with a 9.47 volt bias, a potential of 288 volts on the screen grid and up to 400 volts potential on the plate.
		The reason that the graph starts to look so jumpy is that the current must rise much faster to compensate for the greater drop in comparison to the secondary emission current drop at lower potentials on the plate.
	faculty.frostburg.edu /phys/latta/ee/2ndemission/secondary6au6.htm (675 words)

	[No title] (Site not responding. Last check: 2007-10-09)
		Secondary electrons and ions ejected from the surface may affect the equilibrium plasma characteristics such as species and charge densities, particle energy distributions, and the sheath thickness.
		Our earlier research concentrated on studies of low energy, ion-induced secondary electron emission and negative ion emission from aluminum [1,2], molybdenum [3] and stainless steel surfaces [4] upon which resides a known coverage of oxygen.
		A model used for previous substrates [3] was modified to describe emission from the O/W and Cl/W surfaces; a similar treatment of O/Si(100) surface is under development.
	physics.wm.edu /~champion/PAGES/surface.html (369 words)

	Phototube Detectors
		This secondary emission is multiplied by the gain at each dynode stage, typically referred to as the secondary emission factor, delta.
		Secondary emission occurs via a process which is very similar to the photoelectric process.
		The overall gain of a phototube depends on the number of dynodes in the multiplier section and the secondary emission factor or average number of electrons produced per primary electron for each dynode stage.
	dept.physics.upenn.edu /balloon/phototube.html (2992 words)

	Chemical Vapor-Deposited (CVD) Diamond Films for Electronic Applications (Site not responding. Last check: 2007-10-09)
		Secondary electron emission is the effect in which electrons are emitted from the near surface of a material because of energetic incident electrons.
		The total secondary yield coefficient, which is the ratio of the number of secondary electrons to the number of incident electrons, generally ranges from 2 to 4 for most materials used in such applications.
		Research on field emission from CVD diamond and high-pressure, high-temperature diamond has shown that field emission can be obtained at fields as low as 2x10^4 V/cm.
	www.grc.nasa.gov /WWW/RT1995/5000/5620k.htm (329 words)

	Charging Processes
		For example, the maximum emission yield from impact onto 0.01 micron-sized particles for both conductors and insulators is about 3.5 times higher than onto 1 micron-sized particles [17].
		This extensively used formula for the secondary emission yield from semi-infinite slabs of material approximates the theoretical derivations of Bruining and Jonker in the 1950s.
		Instead, it is possible for secondary electrons to exit from all points of the grain surface, thus increasing the yield over that determined by the Sternglass formula [17].
	www.mpi-hd.mpg.de /dustgroup/~graps/earth/charging.html (3350 words)

	PHY 598 (Venables) Sect A2 (Site not responding. Last check: 2007-10-09)
		Electron emission processes are central to many effects at surfaces and interfaces, and to many techniques for examining the near-surface region.
		Thus the real nature of a field emission tip during use, and indeed of an STM tip, is somewhat shrouded in mystery.
		The secondary electron yield depends on many factors, and is generally higher for high atomic number targets, and at higher angles of incidence.
	venables.asu.edu /grad/sectA2.html (1643 words)

	Statute: § 63.848 Emission monitoring requirements.
		The owner or operator shall compute and record the monthly average from at least three runs for secondary emissions and the previous 12-month average of all runs for the primary control system to determine compliance with the applicable emission limit.
		The results of the emission test using the applicable test methods must be in compliance with the applicable emission limit for existing or new potlines in §§ 63.843 or 63.844.
		The criterion for approval shall be a demonstration (to the satisfaction of the regulatory authority) that the alternative method and alternative emission limit achieve a level of emission control that is the same as or better than the level that would have otherwise been achieved by the applicable method and emission limit.
	www.arb.ca.gov /bluebook/bb05/40cfr/40cfr63_848.htm (1619 words)

	Electric Field Enhanced Secondary Electron Emission From B-Doped Diamond Membrane
		The study of secondary electron emission was performed by measuring the electron beam current passing through membranes, and comparing with incident beam current.
		It was found, that under certain condition of deposition it is possible to produce the diamond films, which possess of the properties to enhance the intensity of incident electron beam in 10 times with a good homogeneity across the surface of membrane.
		Influence of external electric field on secondary emission properties was measured.
	www.eng.auburn.edu /department/ee/ADC-FCT2001/ADCFCTabstract/135.htm (331 words)

	Effect of Shot Noise and Secondary Emission Noise in Scanning Electron Microscope Images (Site not responding. Last check: 2007-10-09)
		Summary: The effect of shot noise and emission noise due to materials that have different emission properties was simulated.
		Local variations in emission properties affect the overall signal-to-noise ratio (SNR) value of the scanning electron microscope image.
		In the case in which emission noise is assumed to be absent, the image SNRs for silicon and gold on a fl background are identical.
	www.scanning-fams.org /scanabstracts/SCANNING04/26036.html (216 words)

	[No title]
		This increase in B mostly comes from a decrease in the emission diameter to around 5 (m; the actual current emitted is typically lower than the tungsten hairpin.
		The Field F plays a similar role to the temperature in thermionic emission, and the governing equation is that by Fowler and Nordheim, derived in 1928 from free electron theory (see Woodruff and Delchar, pages 326-7 or Modinos, p 16).
		FEM images the tip itself, with a plate anode which my be coated with phosphor to detect the intensity of emission from different crystal planes; in more recent experiments a channel plate would be used as an intermediate amplifier.
	venables.asu.edu /sphy/sectA2.doc (2741 words)

	Help: EQUIPOT Spacecraft surface charging code
		Secondary emission yield is a function of the energy of an incoming particle.
		For normal incidence, the secondary electron emission yield due to protons is a function of the energy (in keV) at the surface E
		The secondary electron emission yield due to electrons is given as a function of the energy (in keV) at the surface E
	www.spenvis.oma.be /spenvis/help/background/charging/equipot/equipot.html (2790 words)

	[No title] (Site not responding. Last check: 2007-10-09)
		The speckle-analysis is a new measurement technique to analyze the coherence of secondary emission.
		In contrast the incoherent emission does not exhibit such strong directional fluctuations, since the relative phases of the emitters are defined.
		While typically for strongly non-resonant excitation the coherent emission is dominating, semiconductor structures excited resonantly at the band-edge show a combination of both emission types.
	fred.physik.uni-dortmund.de /speckle.html (363 words)

	[No title]
		A default gain mechanism is to use large area planar metal dynodes with micro-machined apertures for secondary electron impingement and transport, such as metal meshes, or structures similar those used in the Hamamatsu R5900.
		For example, the supports might obscure as much as 10% of the SEM cathode or dynode (on a few cm areal scale), with little effect on the performance of a forward calorimeter, as the effective open detection area is not as critical as in a PMT for single photon detection.
		For the phase I R&D on this project, we propose studying the possibility of this to a sufficient level where information on performance and cost are sufficient to enable a decision to build a prototype calorimeter in subsequent proposal phases.
	www.hep.uiuc.edu /LCRD/EOI_docs/R&Dforlummon.doc (661 words)

	Simulation of secondary electron emission based on a phenomenological probabilistic model
		The model is based on a broad phenomenological fit to data for the secondary emission yield (SEY) and the emitted-energy spectrum.
		We also present details of the electron-cloud simulation code POSINST that are relevant to the secondary emission process.
		M.A. Furman and M.T.F. Pivi, "Simulation of secondary electron emission based on a phenomenological probabilistic model" (June 2, 2003).
	repositories.cdlib.org /lbnl/LBNL-52807 (172 words)

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