US3332606A - Penning type vacuum pumps - Google Patents

Penning type vacuum pumps Download PDF

Info

Publication number
US3332606A
US3332606A US373799A US37379964A US3332606A US 3332606 A US3332606 A US 3332606A US 373799 A US373799 A US 373799A US 37379964 A US37379964 A US 37379964A US 3332606 A US3332606 A US 3332606A
Authority
US
United States
Prior art keywords
cells
cathode
anode
electrons
cathodes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US373799A
Other languages
English (en)
Inventor
Holland Leslie Arthur
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Edwards High Vacuum International Ltd
Original Assignee
Edwards High Vacuum International Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB1084051D priority Critical patent/GB1084051A/en
Application filed by Edwards High Vacuum International Ltd filed Critical Edwards High Vacuum International Ltd
Priority to US373799A priority patent/US3332606A/en
Application granted granted Critical
Publication of US3332606A publication Critical patent/US3332606A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01J41/20—Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps with ionisation by means of cold cathodes using gettering substances

Definitions

  • This invention relates to Penning type vacuum pumps and more particularly to such pumps in which chemically active cathode materials for sorbing gas in vacuum are used.
  • a known form of pump consists of a pair of parallel cathode electrodes with an anode, or multiple anodes, in the inter-space. A magnetic field is used the lines of force being normal to the cathode planes.
  • the cathodes are made of chemically active materials, e.g. titanium or zirconium then the sputtered metal condenses on the vacuum envelope and anode electrode where it sorbs gases by various processes such as the formation of chemical compounds, chemisorption, and diffusion. Continuous sputtering produces fresh layers for adsorption and covers over existing gas containing layers.
  • chemically active materials e.g. titanium or zirconium
  • the present invention contemplates a Penning type ion pump provided with an electrode assembly comprising a cellular anode disposed between a pair of parallel cathodes which are adapted and arranged to be maintained at the same potential, and means for impressing a magnetic field across said electrode assembly in a direction normal to the cathode planes to cause electrons moving in the space within the assembly and within open cells of said cathode to follow spiral paths between said cathodes before being captured, said pump particularly characterized in that said cellular anode comprises nited States Patent O 3,332,606 Patented July 25, 1967 Vice a first set of active cells of dimensions through which the spiraling electrons may pass to sustain a discharge, and a second set of inactive cells through which such spiraling electrons may not pass, said inactive cells having at least one wall in the path of the spiraling electrons to obstruct their passage for preventing a discharge.
  • the said second set of inactive cells comprises open cells having crosssectional dimensions smaller than those of the active cells.
  • the second set of inactive cells comprises cells that are closed and interspersed among the open cells, whereby said cells are inactive.
  • FIGURE 1 is a fragmentary explanatory diagram
  • FIGURE 2 is a diagrammatic plan view of part of an electrode assembly
  • FIGURE 3 is a diagrammatic side elevation of an assembly including electrodes as shown in FIGURE 2;
  • FIGURE 4 is a diagrammatic perspective view of the anode included in FIGURE 3;
  • FIGURE 5 is a plan view of an alternative form of anode
  • FIGURE 6 is a side elevation of the anode shown in FIGURE 5;
  • FIGURE 7 is a further explanatory diagram
  • FIGURE S is an elevation partly in section of a pump embodying the invention.
  • FIGURES 9, l0 and l1 each show pumping seed ClllVeS.
  • FIGURE l illustrates the effect produced when the conventional form of cellular anode is used.
  • the broken lines 1 represent the projection on to the surface of a cathode 2 of the edges of the anode cells and the shaded areas 3 show the region where a net transfer of sputtered metal can occur.
  • the anode electrode is constructed to produce enlarged areas where such net transfer of sputtered metal can occur and FIGURES 2, 3 and 4 show an anode 4 in which the usual single thin walls are replaced by double walls 5.
  • the anode is disposed between a pair of parallel cathodes 6 composed of titanium.
  • the provision of the double walls 5 has the effect of producing spacing of the individual anode cells from each other by rectangular cells 7.
  • the discharge conditions are such that a cold cathode discharge can be sustained within each of the square shaped cells but the dimensions of the rectangular cells are such that a discharge in this region is not possible.
  • each active discharge cell is separated from another active cell by a greater distance than can be obtained easily using a thick-walled anode.
  • the areas on which sputtered material which is redeposited on the cathode surface can now be greatly increased in size and the material deposited in zones farther away from the active bombardment regions of the cathode. Consequently it becomes impossible for the intense discharge region to wander over the cathode surface and reach the most remote redeposited material.
  • the principal sputtering zone of high current density is shown at 8 and the areas where a net transfer of sputtered material can occur are shown at 9.
  • FIGURES 5 and 6 an anode with closed cells 10 and open cells 11 is shown and it will be seen that certain of the open cells are surrounded on four sides by enclosed cells which, from the discharge point of view, are inactive. Thus, such surrounded cells each has projected on the cathode an area of four times the discharge area in which it is possible for sputtered material to be redeposited on the cathode. Such enlarged areas are illustrated by the shaded portions 12 of FIGURE 7.
  • the enclosed cells of the anode can be made by using solid pieces of metal slipped into the apertures of the boxes, this method being preferable to enclosing the boxes with lids because of difficulties in removing the entrapped gas during the pumping cycle.
  • the pump shown consists of a body '13 supporting a magnet 14 and provided With a terminal 15 for the operating voltage supply leads for the electrodes.
  • the anode 4 is of the general form shown in FIGURE 4 and the parallel cathodes 6 are of the general form shown in FIGURE 3.
  • the individual anode cells are half an inch square and half an inch deep, the rectangular spacing cells 7 (FIGURE 4) being one eighth of an inch wide.
  • the cathodes 6 are spaced one inch and a quarter apart.
  • the magnet 13 provides a eld of 1000 gauss and the operating voltage is 6 kv.
  • the pumping speeds indicated by the curves shown in FIGURES 9 and 10 are in litres per second at specific pressures 1and the pressures in torr values.
  • the pumping speed for air as shown by the curve 16 is of the order of 16 litres per second at a pressure of 10-5 torr measured at 10-V5 torr.
  • the curves in FIGURE 10 show the pumping speeds obtained in the case of argon and curve 17 shows a pump speed of the order of 16 litres per second at a pressure of 10-5 torr, measured at 10-5 torr.
  • the volumetric speeds may be measured using two chambers one of which is constituted by the pump, the two chambers being separated by an injuredd plate.
  • the pumping speeds are determined by measuring the pressures in the two vessels, the conductance of the orifice being known.
  • FIGURE 11 shows a curve 18 which indicates the stability of argon pumping with time given in hours
  • the invention may be carried out in ways different from the particular embodiment described.
  • the dimensions of the electrodes, their relative spacing and the operating voltages may be selected to suit required conditions.
  • a Penning type ion pump of the sort provided with (A) an electrode assembly comprising (l) a pair of mutually spaced parallel cathodes which are adapted and arranged to be maintained at the same potential and (2) an anode having a plurality of open cells disposed between said cathodes, and ⁇ (B) means for impressing a magnetic held across said electrode assembly in a directional normal to the cathode planes to cause electrons moving in the spaces within said assembly and Within said open cells to follow spiral paths between the said cathodes before being captured, said pump particularly characterized in that (C) said cellular anode comprises l) a first set of active cells of dimensions through which the spiraling electrons may pass to sustain a discharge, and

Landscapes

  • Electron Tubes For Measurement (AREA)
US373799A 1964-06-09 1964-06-09 Penning type vacuum pumps Expired - Lifetime US3332606A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1084051D GB1084051A (enrdf_load_stackoverflow) 1964-06-09
US373799A US3332606A (en) 1964-06-09 1964-06-09 Penning type vacuum pumps

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US373799A US3332606A (en) 1964-06-09 1964-06-09 Penning type vacuum pumps

Publications (1)

Publication Number Publication Date
US3332606A true US3332606A (en) 1967-07-25

Family

ID=23473918

Family Applications (1)

Application Number Title Priority Date Filing Date
US373799A Expired - Lifetime US3332606A (en) 1964-06-09 1964-06-09 Penning type vacuum pumps

Country Status (2)

Country Link
US (1) US3332606A (enrdf_load_stackoverflow)
GB (1) GB1084051A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3400349A (en) * 1966-01-14 1968-09-03 Varian Associates U-shaped magnetic circuit including three permanent magnets separated by pole pieces
US4820226A (en) * 1987-10-14 1989-04-11 The United States Of America As Represented By The United States Department Of Energy Getter pump for hydrogen and hydrocarbon gases
DE3939571A1 (de) * 1989-11-30 1991-06-06 Leybold Ag Ionenzerstaeuberpumpe
DE102010055420A1 (de) * 2010-12-21 2012-06-21 Vacom Vakuum Komponenten & Messtechnik Gmbh Elektrodenvorrichtung für eine Ionenzerstäuberpumpe

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161802A (en) * 1960-05-27 1964-12-15 Varian Associates Sputtering cathode type glow discharge device vacuum pump

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161802A (en) * 1960-05-27 1964-12-15 Varian Associates Sputtering cathode type glow discharge device vacuum pump

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3400349A (en) * 1966-01-14 1968-09-03 Varian Associates U-shaped magnetic circuit including three permanent magnets separated by pole pieces
US4820226A (en) * 1987-10-14 1989-04-11 The United States Of America As Represented By The United States Department Of Energy Getter pump for hydrogen and hydrocarbon gases
DE3939571A1 (de) * 1989-11-30 1991-06-06 Leybold Ag Ionenzerstaeuberpumpe
DE102010055420A1 (de) * 2010-12-21 2012-06-21 Vacom Vakuum Komponenten & Messtechnik Gmbh Elektrodenvorrichtung für eine Ionenzerstäuberpumpe

Also Published As

Publication number Publication date
GB1084051A (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
US2993638A (en) Electrical vacuum pump apparatus and method
Jepsen Magnetically Confined Cold‐Cathode Gas Discharges at Low Pressures
US4383177A (en) Multipole implantation-isotope separation ion beam source
US4179351A (en) Cylindrical magnetron sputtering source
JPH0358140B2 (enrdf_load_stackoverflow)
US3460745A (en) Magnetically confined electrical discharge getter ion vacuum pump having a cathode projection extending into the anode cell
US3332606A (en) Penning type vacuum pumps
US2983433A (en) Getter ion vacuum pump apparatus
US3161802A (en) Sputtering cathode type glow discharge device vacuum pump
US3216652A (en) Ionic vacuum pump
US3542488A (en) Method and apparatus for producing alloyed getter films in sputter-ion pumps
US3535054A (en) Cold-cathode discharge ion pump
US3070719A (en) Cathodes for magnentically-confined glow discharge apparatus
US3376455A (en) Ionic vacuum pump having multiple externally mounted magnetic circuits
US3452923A (en) Tetrode ion pump
JPS6143427A (ja) スパツタエツチング装置
US3107844A (en) Single cell vacuum apparatus
Robins Mass Peaks from Adsorbed Gases in a Single-Focusing Mass Spectrometer
US3042824A (en) Improved vacuum pumps
US3217974A (en) Dual surface ionic pump with axial anode support
US3381890A (en) Vacuum apparatus
US3176906A (en) Ion pump
US3118077A (en) Ionic vacuum pumps
US3115297A (en) Vacuum pump
US3614264A (en) Ionization getter pump