US3240421A - Ion transport pump - Google Patents

Ion transport pump Download PDF

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Publication number
US3240421A
US3240421A US253640A US25364063A US3240421A US 3240421 A US3240421 A US 3240421A US 253640 A US253640 A US 253640A US 25364063 A US25364063 A US 25364063A US 3240421 A US3240421 A US 3240421A
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Prior art keywords
electrode
electrodes
envelope
electron
anode
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US253640A
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English (en)
Inventor
Philo T Farnsworth
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TDK Micronas GmbH
International Telephone and Telegraph Corp
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Deutsche ITT Industries GmbH
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Priority to US183440A priority Critical patent/US3181028A/en
Application filed by Deutsche ITT Industries GmbH filed Critical Deutsche ITT Industries GmbH
Priority to US253640A priority patent/US3240421A/en
Priority to FR929804A priority patent/FR1355912A/fr
Priority to GB2173/64A priority patent/GB1045721A/en
Priority to NL6400494A priority patent/NL6400494A/xx
Priority to FR961405A priority patent/FR85205E/fr
Priority to BE642926A priority patent/BE642926A/xx
Priority to CH82764A priority patent/CH428073A/de
Application granted granted Critical
Publication of US3240421A publication Critical patent/US3240421A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J41/00—Discharge tubes for measuring pressure of introduced gas or for detecting presence of gas; Discharge tubes for evacuation by diffusion of ions
    • H01J41/12—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps
    • H01J41/18—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of cold cathodes

Definitions

  • the present invention relates to an ion transport pump, and more particularly to an electron discharge device for use in evacuating closed vessels.
  • ions are rst formed from neutral atoms and then transported by electric field and space charge forces to a region remote from the point of formation, where the ions are neutralized and then scavenged by means of a conventional vacuum pump.
  • the pressure in the vessel being evacuated reduces, the number of neutral gas atoms for ionization correspondingly reduces. Since the rate of ionization is directly related to the number of neutral atoms to be ionized, it is important in obtaining an ecient evacuating operation that the capability of ionization be relatively high at all times. Additionally, it is important that once the ions are formed, they be transported to a region from which the probability of escape retrogressively is minimal. Furthermore, when such ions are transported to this region, it is necessary that they be neutralized and scavenged continuously such that the processes mentioned in the foregoing can continue without interruption, thus reducing the pressure in the vessel being evacuated to an extremely low level.
  • an object of this invention to provide a transport pump wherein the combined forces of an electrical field and an electron discharge serve in propelling ions in a common direction from a region or regions of ionization.
  • a transport pump comprising an envelope divided into first and second tandem pump sections.
  • first section there is provided rst and second spaced-apart electron-repelling electrodes which define the opposite ends, respectively, of a space current region.
  • An anode electrode is interposed between said rst and second electrodes and surrounds said space current region.
  • the envelope is provided with an inlet port which directly communicates with this space current region.
  • the second electrode is provided witha beam-receiving aperture which serves as the only means of gaseous communication between the aforesaid rst and second pump sections.
  • the second pump section is provided with a third electron-repelling electrode which is spaced from the second electrode for defining the opposite ends, respectively, of a second space current region.
  • a second anode electrode is interposed between the second and third electrodes and surrounds the second space current region.
  • the third electrode is provided with a second aperture which may be aligned with the aperture in the second electrode.
  • a fourth electron-repelling electrode is spaced from the third electrode and may be aligned with both of the aforesaid apertures.
  • An exhaust port in the envelope directly ice communicates with the space between the third and fourth electrodes.
  • some electrons are directed from said fourth electrode through the closer of said apertures and into the second pump section.
  • a first electric field is established within the second pump section between said second and third electrodes for oscillating an ionizing cloud of electrons therebetween.
  • Similar means establish another field within the first pump section between the rst and second electrodes for oscillating another ionizing cloud of electrons therebetween.
  • These elds are arranged to have an overall potential distribution which generally progresses from a maximum positive value within the first pump section to a minimum negative value in the second pump section. Therefore, ions developed in both pump sections are propelled through the aforesaid apertures toward the fourth electrode at which they become neutralized. Once neutralized, the atoms can be pumped from the envelope via the exhaust port.
  • FIG. l is a longitudinal sectional illustration of one embodiment of this invention.
  • FIG. 2 is a graph of the potential distribution along the axis of the pump.
  • FIG. 3 is -a fragmentary sectional view of another embodiment of this invention.
  • a glass envelope 1 which is generally cylindrical in shape is hermetically sealed with the exception of an inlet port 2 at one end and an exhaust port 3 at the opposite end.
  • the envelope 1 is of two different diameter sections, the larger diameter section being indicated by the numeral 4 and the smaller diameter section by the numeral 5.
  • the larger diameter section 4 has fixedly mounted therein two facing concave cathodes and electron-repelling electrodes 6.and 7, respectively, which are segments of spheres and which preferably are formed of some suitable secondary emitting material such as beryllium copper, stainless steel and the like. These electrodes are spaced apart as shown and are arranged coaxially with the tube axis which passes through the centers thereof.
  • a metallic disc 8 which is secured to the periphery of the electrode 6 and also to the wall of the envelope 1 is provided with a multiplicity of apertures throughout the entire circumference thereof.
  • the electrode 7 should be impervious (with the exception of an aperture) to the flow of gas such that it corresponds to a Wall or partition within the envelope 1. Since the electrode 7 as shown is somewhat smaller in diameter than the envelope 1, an annular metal disc 9 is welded around its inner perimeter to the electrode 7 and is similarly welded or fused around the entire outer perimeter thereof to the envelope 1. The importance of this feature will be explained more fully hereinafter.
  • the central portion of the electrode 7 is provided with the aforesaid aperture 10 which coincides with the tube axis.
  • the two electrodes 61and 7 are spaced relatively widely apart.
  • an anode assembly which consists of two cylindrical ⁇ sleeves 11 and 12 of conductive material which are coaxial with respect to the tube axis and axially spaced apart as shown.
  • These sleeves may be in the form of metallic tubes or conductive coatings on the inner wall of the lenvelope 1, but in any event they are insulated from each other. Otherwise, these sleeves should be made of non-magnetic material.
  • a frusto- 4conical element 13 made of a conductive material which is nonmagnetic.
  • This element 13 is coaxially mounted with its smaller diameter end 14 being adjacent to the electrode 6 andthe larger diameter end 15 adjacent to the sleeve 11.
  • This larger diameter end 15 approximates in size the diameter of the sleeve 11.
  • a mounting 16 for the element 13 for securing the latter in place may -be substantially identical to the apertured disc 8 which is -used to support the electrode 6.
  • the element,13 may be formed of metal mesh which permits the free flow of gas therethrough and into the space inside the two anode sleeves 11 and 12.
  • a metallic tubular element 17 which -is held in its illustrated coaxial position by means of a radial flange 18 suitably secured to the wall of the envelope 1.
  • the diameter of this element 17 is approximately the same as that of the electrode 7.
  • the sleeve 11 and the frusto-conical element 13 are electrically connected together by means of a wire 20 or the like.
  • the sleeve 12 and the tubular element 17 are electrically connected together by means of a suitable wire 21 or the like.
  • a 'solenoid 22 surrounds the larger envelope section 4 and is supplied with direct current from a source 23 for establishing a longitudinal magnetic field in the space between the electrodes 6 and 7.
  • the smaller envelope section 5 is cylindrical and coaxial with respect to the larger section 4, and in effect constitutes an extension thereof.
  • another cathode or electron-repelling electrode 24 which is spherically concave facing the electrode 7. Both the concave and convex surfaces of this electrode 24 are coaxial and symmetrical with respect to the majo-r axis of the entire tube.
  • An annular flange portion 25 serves to mount the outer perimeter of the electrode 24 to the wall of the envelope, this flange v25 being made of a Asuitable metal which is nonrnagnetic.
  • a coaxially positioned aperture 26 is provided in electrode 24 as shown.
  • anode sleeve 27 Interposed between the two electrodes 7 and 24 is a frusto-conically shaped anode sleeve 27 which is held in its illustrated coaxial position by means of a suitable annular disc or support 28.
  • the :smaller diameter end 29 of this anode is positioned adjacent to the convex surface of the electrode 7 while the larger diameter end 30 is located opposite the electrode 24.
  • a 'concave focusing cup 31 which faces :the anode 27 and has a diameter which is substantially the same size as that of the anode end 29.
  • This cup 31 is coaxially positioned and carries on its surface 32 a material which is secondary emissive. The emission ratio of this material is preferably greater than unity. Also, this cup has an aperture which is coextensive with the aperture 10 in the electrode 7.
  • the cup 31 may be fabricated of beryllium copper or the like.
  • a cathode cup 33 which is coaxial and spherically concave facing the electrode 24.
  • This cathode 33 unlike the electrode 24, is supported in the envelope section 5 by means of three or more angularly spaced wires or supports 34 having substantial spacing therebetween such that the chamber or space between the cathode 33 and the electrode 24 is in direct communication with the exhaust port 3. It is desirable for the cathode 33 to be electron emissive under ion as well as electron bombardment, .and a suitable material for this cathode may be Iberyllium copper.
  • the center of curvature of the cathode 33 is located within the aperture 26 of the electrode 24.
  • the center of curvature of the electrode 24 is located on the tube axis about midway between the ends -of the anode cone 27.
  • the center of curvature of the electrode 7 is on thetube axis and adjacent to the right-hand end ofthe anode sleeve 12.
  • the radius of curvature of the electrode 6 is also located on the tube axis at a point adjacent to the left-hand end of the sleeve 11.
  • Another solenoid 35 surrounds the envelope section 5 and extends for a distance which approximates that between electrode 7 and cathode 33.
  • a battery 36 supplies the solenoid with direct current whereby a longitudinally extending magnetic field between the electrodes 7, 24 and 33 may be established.
  • the operating circuitry for the pump grounds the two electrodes 6 and 7 as shown and interconnects the anode sleeves 11 andlZ by means of a battery 37, the positive terminal being connected to the sleeve 11 and the negative terminal to the sleeve 12.v
  • the battery 37 delivers approximately 90 volts.
  • the midpoint of the battery 37 is connected to the positive terminal of a high voltage supply 38, the negative terminal of the latter being grounded as shown.
  • This supply 38 in a working embodiment of this invention provides approximately 1,000-volts.
  • a battery 39 has its positive terminal connected to the anode cone 27 and its negative terminal to the electrode 24.
  • a variable tap 40 on the battery 39 connects approximately the midpoint thereof to ground as shown. This battery 39 should deliver a voltage of from 500 to 1,000 volts.
  • Another battery 41 has its positive terminal connected to the electrode 24 and its negative terminal to cathode 33.
  • the value of this battery 41 as well as the other 'batteries in the total circuit are so selected or adjusted that the cathode 33 operates at a voltage of about 2,000- volts negative with respect to ground.
  • the vacuum pump 'coupled to the exhaust fitting 3 is operated to reduce the pressure inside the envelope 1 and also inside the vessel to be evacuated to a pressure of from 10-2 to 10-3 millimeters of mercury.
  • any ionized gas atoms in the larger envelope section 4 within the region surrounded by the anode sleeves 11 and 12 will tend to fall down field toward the potential minimum at the cathode 33.
  • the objective of this invention is accomplished by the ionization of neutral gas atoms in the left-hand portion of the pump and the transporting or pumping of these ionized atoms toward the right-hand end of the tube from which they may be scavenged by means of the conventional vacuum pump attached to the exhaust port 3.
  • This pumping action is achieved as follows. After the pressure in the envelope 1 has been reduced to a value of about l0"3 millimeters of mercury by means of the conventional vacuum pump attached to the exhaust port 3, a gaseous discharge occurs inside the tube which results in the development of free electrons and ions which llow in directions corresponding to the forces acting thereon. For example, any ions formed in the chamber between the two electrodes 7 and 24 or between the electrode 24 and cathode 33 will be propelled toward the cathode 33.
  • the space current or electron concentration developed in the axial or longitudinal region of the ypump section 4 between the electrodes 6 and 7 is of pencil-like shape but in cross-section is substantially larger in size than the aperture in the electrode 7.
  • the crosssectional size of the space current region will correspond to the size of the opening 14 in the anode element 13.
  • the oscillating space current between the two electrodes 6 and 7 will increase until the number of electrons released at the dynode 6 by the initial beam is equal to the number of electrons collected by the anode assembly, or until the process is stopped by changing the anode potential or the like.
  • the first of these is the space charge which develops in the space current when the number of released electrons becomes very large. This charge tends to drive the peripheral electrons, i.e., the electrons more remote from the axial center of the tube, toward the anode, making the collection thereby more probable.
  • the second factor is the transverse component of the electrostatic field within the tube. Such a component exists due to the curvature of the lines of force at the ends of the tubular anode elements.
  • Electrons liberated from the dynode 6 are accelerated toward the electrode 7 but fail to reach it. They are retarded and brought to rest just before arrival, after which they are accelerated in the opposite direction. This continues'until, probably after several traversals of the chamber between the two electrodes 6 and 7, the liberated electrous, or some of them, encounter and ionize gas molecules.
  • the positive ions thus released are exposed to a combination of field and charge forces which cause movement thereof in a direction which is the result of such forces; however, before examining in detail the motion of these ions, the action of the oscillating electrons will be further considered.
  • the electrons liberated from the ionized gas molecules join the original electrons in oscillating back and forth between the electrodes 6 and 7; however, the ion-derived electrons oscillate through a shorter traversal.
  • the space current region between the two electrodes 6 and 7 will be lilled with oscillating electrons traveling over path lengths which vary, some being longer than others.
  • the frusto-conical element 13 is so shaped that the positive potential applied thereto will obviously repel the ion toward the right, or in other words toward the electrode 7. This being true, the ion is prevented from being attracted toward the dynode 6 and thereby neutralized to become once again a neutral atom.
  • the ion In its flight toward the electrode 7, the ion encounters the dropping gradient developed by the two anode sleeves 11 and 12 and alsois attracted toward the axial center of the tube by the axial electron concentration. Thus, when the ion arrives at the electrode 7, it can be traveling axially through the electron concentration and penetrate the aperture 10. While it is possible for the same ion to continue to fall through the electron concentration because of the potential gradients inside the pump and eventually end up at the cathode 33, this does not necessarily happen as will be explained in more detail hereinafter.
  • the second stage of the pump constitutes those elements in the envelope section 5 which include and lie between the electrodes 7 and 24.
  • the initial beam which emanates from the cathode 33 passes first through the aperture 26 and secondly through the aperture 10. However, some of these electrons do not pass through the aperture 1t) but instead strike the bottom 32 of the focusing cup 31. This results in the liberation of secondary electrons which are accelerated by the anode 27 toward the electrode 24. However, as in the case of the first stage just described, these electrons never quite reach the electroder 24 but are turned rearwardly and accelerate toward the cup 31. Since the cup 31 is slightly more positive than the electrode 24, the electrons will once again impact the bottom of the cup and liberate more secondaries.
  • Electron multiplication continues until a stable space current is developed, this space current being composed of electrons oscillating through the center of the anode 27 between ⁇ the two electrodes 7 and 24. Electron multiplication may be enhanced by use of the multipactoring circuits and principles disclosed in my application Serial No. 183,440, led Mar. 29, 1962, now Patent No. 3,181,028, entitled Vacuum Pump.
  • any ions which are developed within the space of the anode 27 will be propelled toward the electrode 24 and also toward and through the aperture 26 the same as was true in connection with the first stage described previously. All of the ions which pass through the aperture 26 fall toward and against the cathode 33 at which they are converted into neutral atoms which no longer respond to any electrical fields ⁇ or charge forces. Instead, these neutral atoms are scavenged via the exhaust port 3 by means of the conventional vacuum pumping apparatus which is connected thereto. The process of ion transport is continuous and so is the reduction in gas pressure inside the pump.
  • Some of the ions passing through the aperture from left to right recombine with electrons and become neutral atoms. These atoms randomly travel through the space between the two electrodes 7 and 24 until they become reionized. The newly formed ions travel toward the electrode ⁇ 24 through the aperture 26 and are neutralized at the cathode 33.
  • FIG. 3 In order to facilitate the establishment of relatively large spa-ce currents within the two pump sections, the alternative structure of FIG. 3 is preferred.
  • This structure is quite similar to the cathode assembly 7, 31 of FIG. l, but differs inthe separation of the two cups 7 and 31 and the disposition therebetween of an annular thermionic emitter 52 yof tungsten or the like.
  • This emitter is maintained suitably negative with respect to both cups 7 and 31, so as to provide currents of from l0 to 50 milliamperes through both apertures 10 and 10a.
  • T-hese cups 7 and 31 are electrically connected together by means of metallic posts 53 which also serve as supports for securing the cup 31 in position with respect to cup 7.
  • the electrons from this emitter 52 which penetrate the apertures 10 and 10a, serve in establishing initially the axial electron concentrations in the two pump sections.
  • solenoids 22 and 35 it is the purpose of the solenoids 22 and 35 to produce focusing magnetic elds which prevent collection of the electrons by the respective anodes 11, 12 and 27. While solenoids have been shown, it will be understood by a Alternatively electheillustrated'pump which is drawn to scale provides the necessary electrostatic forces for the necessary focusing effects. In a working embodiment of the invention, however, it has been found that the solenoids 22 and 35 improve somewhat the pump operation.
  • the pressure at the inlet port (hence in the evacuated vessel) can be lowered to values from 10-6 to 10-lo millimeters -of mercury, while the pressure at the exhaust port 3 (hence in the space between the electrodes 7 and 24) is at a value somewhere between 10-2 to 10-3 millimeters of mercury.
  • stage D the stage on the right-hand side of electrode 7 in FIG. l, hereinafter identified as stage D
  • stage C the stage on the lefthand side of electrode 7 in FIG. 1, hereinafter referred to as stage C
  • the aperture in electrode 7, between the two stages has an area A (in sq. cm.)
  • n the number of electrons per cubic centimeter, and if the effective part of the discharge (that is, the part which is capable of directing ions through aperture 10) is a cylinder of length L and cross-section A1 there will thus be l'generated per second which constitute the ion current passing through' the aperture.
  • the electrons oscillate many times in opposite directions before they are collected by the anode, and during these oscillations, they are available to generate ions.
  • the electrodes 7 and 24 correspond to walls or partitions which are almost completely impervious to gas flow.
  • the axial electron beam, and the various electrode arrangements during pumping operation, ion fiow through the apertures in the direction from the inlet port 2 to the exhaust port 3 is encouraged and is at a greater rate than How in the opposite direction of neutral gas molecules.
  • the mechanism which includes the particular electrodes 7 and 24 thereupon constitutes differential flow means whereby the ion flow in one direction exceeds neutral gas fiow in t-he opposite direction.
  • a transport pump comprising an envelope having spaced apart inlet and exhaust ports, means establishing an electric field between said inlet and exhaust ports having a potential which progressively increases from a low value in a region adjacent to said exhaust port to a higher value in a region adjacent to said inlet port, means for forming within said field an electron cloud having electrons which oscillate at ionizing velocities within the confines of said field, ions resulting therefrom thereby being propelled into the region of low potential from which they may be scavenged in the form of neutral atoms.
  • a transport pump comprising an envelope having spaced apart inlet and exhaust ports, means establishing an electric field between said inlet and exhaust ports having a potential which progressively increases from a low value in a region adjacent to said exhaust port to a higher value in a region adjacent to said inlet port, a wall member in said envelope extending across said field in between said regions, said wall having a flowrestricting orifice, means for forming a cloud of oscillating electrons within said field for ionizing a gas, ions resulting therefrom thereby being propelled into the region of low poten-tial from which they may be scavenged in the form of neutral atoms.
  • a transport pump comprising an envelope having spaced apart inlet and exhaust ports, means establishing an electric field between said inlet and exhaust ports having a potential which progressively increases from a low value in a region adjacent to said exhaust port to a higher value in a region adjacent to said inlet port, means for developing an electron space current in said field for ionizing a gas therein, ions resulting therefrom thereby being propelled into the region of low potential, means interposed in said field between said exhaust and inlet ports for restricting gas fiow in a direction from said exhaust port toward said inlet port, and means for neutralizing ions in the region of said low potential.
  • a transport pump comprising an envelope having spaced apart inlet and exhaust ports, means establishing an electric field between said inlet and exhaust ports having a potential which progressively increases from a low value in a region adjacent to said exhaust port to a higher value in a region adjacent to said inlet port, means producing an electron beam which flows through said field from the region of low value to the region of higher value, means for developing an electron space current in a region surrounding said electron beam for ionizing a gas which permeates said fields, means disposed adjacent to said region of higher value and also said inlet port for directing'ions in a direction from said inlet port toward said exhaust port, means interposed in said eld between said exhaust and inlet ports for restricting gas liow in a direction from said exhaust port toward said inlet port, said beam-producing means including means for neutralizing ions in the region of said low value.
  • a transport pump comprising an envelope, first and second electron-repelling electrodes mounted in said envelope in spaced-apart relation for defining a space current region therebetween, an anode electrode mounted -in said envelope between said first and second electrodes and surrounding said space current region, a third electronrepelling electrode mounted in said envelope and spaced from said second electrode, said first, second and third electrodes lbeing, tandemly arranged 4with said second electrode being between said first and third electrodes, said second electrode having a lbeam-receiving aperture therein, inlet and exhaust ports in said envelope, said inlet port directly communicating with 4the space between said first and second electrodes, said exhaust port communicating with the space between said second and third electrodes, and means including said first, second and anode electrodes establishing an electric field between said first and second electrodes to cause electrons to oscillate repeatedly therebetween in said space current region.
  • said second electrode constitutes a partition which divides said envelope into two gas chambers with the only communication therebetween being by way of said aperture, and means including said anode electrode which directs a majority of ions formed in said space current region in a direction from said first electrode toward said second electrode, whereby said ions fiow through said aperture and onwardly to said third electrode where they become neutralized.
  • said second electrode constitutes a partition which divides said envelope into two gas chambers with the only communication therebetween being by way of said aperture
  • said anode electrode is of frusto-conical sleeve shape with the smaller end thereof being adjacent to said first electrode and the larger end thereof being adjacent to said second electrode, and means for retaining electrons within said space current region for a period of time sufiicent to produce ionization.
  • a transport pu-mp comprising an envelope, first and second electron-repelling electrodes mounted in said envelope -in spaced-apart relation for defining a space current region therebetween, an anode electrode mounted in said envelope between said first and second electrodes and surrounding said space current region, a third electron-repelling electrode mounted in said envelope and spaced from said second electrode, said first, second and third electrodes being tandemly arranged with said second electrode lbeing between said first and third electrodes, said second electrode having a beam-receiving aperture therein, inlet and exhaust ports in said envelope, said inlet port communicating with the space between said first and second electrodes, said exhaust lport communicating with the space between said second and third electrodes, and means for directing electrons from said third electrode through said aperture and against said first electrode at velocities which produce secondary e-mission from the latter, and means for applying an electric field -between said first and second electrodes which causes electrons to oscillate repeatedly therebetween in said space current region.
  • a transport pump comprising an envelope having spaced-apart inlet and exhaust ports, first and second tandem pump sections in said envelope; said first section including first and second spaced-apart electron-repelling electrodes which define the opposite ends respectively of a space current region, a first anode electrode interposed between said first and second electrodes and surrounding said space current region, said space current ⁇ region directly communicating with said inlet port, said second electrode having a first beam-receiving aperture therein; said second section having a third electron-repelling electrode spaced from said second electrode for defining the opposite ends respectively of a second space current region, a second anode electrode interposed between said second and third electrodes and surrounding said second space current region, said third electrode having a second ,beam-receiving aperture which is aligned with said first beam-receiving aperture; a fourth electron-repelling electrode spaced from said third electrode and being aligned with both said first and second apertures, said exhaust port directly communicating with the space between said third and fourth electrodes; means for est
  • a transport pump comprising an envelope having spaced-apart inlet and exhaust ports, first and second tandem pump sections in said envelope; said first section including first and second spaced-apart electron-repelling electrodes which define the .opposite ends respectively of a space current region, a first anode electrode interposed between said first and second electrodes and surrounding said space current region, said space current region directly communicating with said inlet port, said second electrode having a first beam-receiving aperture therein; said second section having a third electron-repelling electrode spaced from said second electrode for defining the opposite ends respectively of a second space current region, a second anode electrode interposed between said second and third electrodes and surrounding said second space current region, said third electrode having a second beam-receiving aperture which is aligned with said first beam-receiving aperture; a fourth electron-repelling electrode spaced from said third electrode and being aligned with both said first and second apertures, said exhaust port directly communicating with the space between said third and fourth electrodes; said second electrode being
  • a transport pump comprising an envelope having inlet and exhaust ports, first and second spaced-apart electrodes having electron-repelling surfaces, respectively, which face each other and which extend transversely to the direction of spacing therebetween, annular anode means interposed between said surfaces, said anode means surrounding a space current region between said surfaces, said second electrode'being in the form of a partition which provides a gas chamber within said envelope, said inlet port directly communicating with said chamber, said second electrode having a kcentrally located beam-receiving aperture therein, a third electrode spaced from said second electrode on the side opposite said first electrode, said third electrode being in the form of a partition within said envelope thereby forming with said second electrode a second gas chamber, said third electrode having a centrally located beam-receiving aperture which is longitudinallyaligned with the first-mentioned aperture, said third electrode having an electronrepelling surface facing said second electrode which extends transversely of the direction of spacing between said second and third electrodes, said second electrode having an electron-emitting
  • the transport of claim 13 including means for providing an electron discharge in said space current regions, means including said second and third electrodes and said second anode means for oscillating electrons in the space current region between said second and third electrodes, means including said first and second electrodes and said first anode means for oscillating electrons in the space current region between said first and second electrodes, and means including the aforesaid electron-directing and electron-oscillating means for providing an electric field which progresses generally from a given high value in the first-mentioned chamber to a given lower value at said cathode electrode, whereby ions created in both said chambers will migrate through said apertures toward said cathode electrode.
  • a transport pump comprising an envelope having inlet and exhaust ports, first and second spaced-apart electrodes having electron-repelling surfaces, respectively, which face other and which extend transversely to the di-rection of spacing therebetween, an annular anode assembly interposed between said surfaces, said anode assembly coaxially surrounding an elongated space current region which extends between said surfaces, said assembly including two axially spaced electrically insulated cylindrical surfaces and a frusto-conically shaped element electrically connected to the one of said cylindrical surfaces which is closest to said first electrode, said element coaxially surrounding said space current region and having a smaller diameter end adjacent to said rst electrode surface; said second electrode 'being in the form of a partition which provides a gas chamber within said envelope, said inlet port directly communicating with sai-d chamber, said second electrode having a centrally located beam-receiving aperture therein, a third electrode spaced from said second electrode on the side opposite said first electrode, said third electrode being in the form of a partition within said envelope
  • the transport pump of claim 15 including means for directing electrons in a stream-like form from said cathode surface through both beam-receiving apertures and into the space current region between said first and second electrodes, means including said second and third electrodes and said frusto-conical anode for oscillating electrons in the space current region between said second and third electrodes, means including said first and second electrodes and said anode assembly for oscillating electrons in the space current region between said first and second electrodes, and means including the aforesaid electron-directing and electron-oscillating means for providing an electric field which progresses generally from a given high value in the first-mentioned chamber to a given lower value at said cathode electrode, whereby ions created in both said chambers will migrate through said apertures toward said cathode electrode.
  • a transport pump comprising an envelope, first and second electron-repelling electrodes mounted in said envelope, said electrodes being spaced apart along an axis and having surfaces which are spherically concave facing each other, the surface of said rst electrode having a secondary emission ratio greater than unity, the spherical curvature being coaxial with respect to said axis; an annular anode assembly in said envelope interposed between said surfaces and coaxially surrounding asid axis, said assembly including two axially spaced electrically insulated cylindrical surfaces and a frustoconically shaped element disposed adjacent to the surface of said first electrode, said element having its smaller diameter end adjacent to said first electrode surface; said second electrode being in the form of a partition which provides a gas chamber within said envelope, said second electrode having a coaxially located aperture, an inlet port in said envelope which communicates directly with said chamber, a third electron-repelling electrode mounted in said envelope and spaced from said second electrode on the side opposite said first electrode, said third electrode having a surface which
  • the transport pump of claim 17 including means for generating and directing electrons through said apertures and into said chambers, means including said second and third electrodes and said frusto-conical anode for oscillating electrons in a direction axially between said second and third electrodes, means including said first and second electrodes and said anode assembly for oscillating electrons in a direction axially -between said first and second electrodes, and means including the aforesaid electron-directing and electron-oscillating means for providing an electric field which progresses generally from a -given high value in the first-mentioned chamber to -a given low value at said cathode electrode, whereby ions created in lboth said chambers will migrate through said apertures toward said cathode electrode.
  • a transport pump comprising an envelope having inlet and exhaust ports, first and second spaced-apart electrodes having electron-repelling surfaces, respectively, which face each other and which extend transversely to the direction of spacing therebetween, annular anode means interposed between said surfaces, said anode means surrounding a space current region between said surfaces, said second electrode lbeing in the form of a partition which provides a gas chamber within said envelope, said inlet port directly communicating ⁇ with said chamber, said second electr-ode having a centrally located beam-receiving aperture therein, a third electrode spaced from said second electrode on the side opposite said first electrode, said third electrode being in the form of a partition within said envelope thereby forming with said second electrode a second gas chamber, said third electrode having a centrally located beam-receiving aperture which is longitudinallyA aligned with the first-mentioned aperture, said third electrode having an electron-repelling surface facing said second electrode which extends transversely of the direction of spacing between said second and third electrodes, said second electrode
  • 201A transport pump comprising an envelope having inlet and exhaust ports, rst and second spaced-apart electrodes having electron-.repelling surfaces, respectively, which face each other and which extend transversely to the direction of spacing therebetween, annular anode means interposed lbetween said surfaces, said anode means surrounding a space current region between said surfaces, said second electrode being in the form of a partition which provides a gas chamber within said envelope, said inlet port directly communicating with said chamber, said second electrode having a #centrally located beam-receiving aperture therein, a third electrode spaced from said second electrode ⁇ on the side opposite said first electrode, said third electrode being in the form of a partition within said envelope thereby forming with said second electrode a second gas chamber, said third electrode having a centrally located beam-receiving aperture which is longitudinally aligned with the first-mentioned aperture, said third electrode having an electron-repelling surface facing said second electrode which extends transversely of the direction of spacing between said second and third electrodes,
  • said second electrodey having a dynode element electrically connected thereto and mounted on the side thereof opposite from said first electrode, said dynode element having an aperture in the central portion thereof which is aligned with the aperture in said Isecond electrode, a thermionic cathode interposed between said second electrode and said dynode element adjacent the apertures thereof whereby electrons may be directed through said apertures, second annular anode interposed between said dynode element and said third electrodeV and surrounding a space current region therebetween, and means for neutralizing ions after they pass from said second chamber and through the aperture of said third electrode.
  • a transport pump comprising means for ionizing a gas, means for propelling ions of said ygas in a predetermined direction, spaced apart inlet and exhaust means disposed with said ionizing and propelling means being therebetween, and differential flow means in the path of said ions providing for predetermined flow of ions in said predetermined direction and for a more restricted flow of neutral gas in the opposite direction, said differential flow means including partition means substantially im-v pervious to gas flow positioned between said ionizing means and said exhaust means, said partition means being provided with an ion beam-receiving opening smaller in area than the impervious portion of said partition means.
  • a transport pump comprising an envelope, means dening two spaced apart electron-reversing fields between which electrons oscillate repeatedly, said means also dening a space current region between said fields, means for propelling ions created within said space current region in a predetermined direction, spaced apart inlet and exhaust portions in said envelope, the firstrnentioned means being disposed between said inlet and exhaust portions, and differential flow means interposed between one of said fields and said exhaust portion providing for a predetermined flow of ions in said predetermined direction and a more restricted ow of neutral gas in the opposite direction.

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  • Electron Tubes For Measurement (AREA)
US253640A 1962-03-29 1963-01-24 Ion transport pump Expired - Lifetime US3240421A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US183440A US3181028A (en) 1962-03-29 1962-03-29 Ion transport vacuum pump
US253640A US3240421A (en) 1963-01-24 1963-01-24 Ion transport pump
FR929804A FR1355912A (fr) 1962-03-29 1963-03-29 Pompe à vide
GB2173/64A GB1045721A (en) 1963-01-24 1964-01-17 Ion transport pump
NL6400494A NL6400494A (sv) 1963-01-24 1964-01-23
FR961405A FR85205E (fr) 1963-01-24 1964-01-24 Pompe à vide
BE642926A BE642926A (sv) 1963-01-24 1964-01-24
CH82764A CH428073A (de) 1963-01-24 1964-01-24 Ionenpumpe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US253640A US3240421A (en) 1963-01-24 1963-01-24 Ion transport pump

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US3240421A true US3240421A (en) 1966-03-15

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US253640A Expired - Lifetime US3240421A (en) 1962-03-29 1963-01-24 Ion transport pump

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US (1) US3240421A (sv)
BE (1) BE642926A (sv)
CH (1) CH428073A (sv)
GB (1) GB1045721A (sv)
NL (1) NL6400494A (sv)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3394874A (en) * 1967-02-09 1968-07-30 Gen Electrodynamics Corp Ion pumping electron gun
US4174907A (en) * 1975-06-09 1979-11-20 Massachusetts Institute Of Technology Fluid mixing apparatus
US20060250746A1 (en) * 2005-05-06 2006-11-09 Cool Shield, Inc. Ionic flow generator for thermal management

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2765392B1 (fr) * 1997-06-27 2005-08-26 Pixtech Sa Pompage ionique d'un ecran plat a micropointes
US10455683B2 (en) 2016-05-31 2019-10-22 Agilent Technologies, Inc. Ion throughput pump and method

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636664A (en) * 1949-01-28 1953-04-28 Hertzler Elmer Afton High vacuum pumping method, apparatus, and techniques

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2636664A (en) * 1949-01-28 1953-04-28 Hertzler Elmer Afton High vacuum pumping method, apparatus, and techniques

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3394874A (en) * 1967-02-09 1968-07-30 Gen Electrodynamics Corp Ion pumping electron gun
US4174907A (en) * 1975-06-09 1979-11-20 Massachusetts Institute Of Technology Fluid mixing apparatus
US20060250746A1 (en) * 2005-05-06 2006-11-09 Cool Shield, Inc. Ionic flow generator for thermal management
US7236344B2 (en) 2005-05-06 2007-06-26 Cool Shield, Inc. Ionic flow generator for thermal management

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BE642926A (sv) 1964-07-24
GB1045721A (en) 1966-10-19
NL6400494A (sv) 1964-07-27
CH428073A (de) 1967-01-15

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