US3382397A - Ion source having a high work function material coating the outer surface of the ionizer - Google Patents

Ion source having a high work function material coating the outer surface of the ionizer Download PDF

Info

Publication number
US3382397A
US3382397A US410584A US41058464A US3382397A US 3382397 A US3382397 A US 3382397A US 410584 A US410584 A US 410584A US 41058464 A US41058464 A US 41058464A US 3382397 A US3382397 A US 3382397A
Authority
US
United States
Prior art keywords
ion source
work function
coating
ionizer
porous
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
US410584A
Other languages
English (en)
Inventor
Zalm Pieter
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.)
US Philips Corp
North American Philips Co Inc
Original Assignee
US Philips Corp
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 claimed from NL6401192A external-priority patent/NL6401192A/xx
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3382397A publication Critical patent/US3382397A/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
    • H01J27/00—Ion beam tubes
    • H01J27/02—Ion sources; Ion guns
    • H01J27/26—Ion sources; Ion guns using surface ionisation, e.g. field effect ion sources, thermionic ion sources

Definitions

  • ABSTRACT 015 THE DESCLGMIRE An ion source comprising a supply of an ionizable material behind a porous tungsten substrate having on its outer surface a coating of iridium, ruthenium, rhenium, or osmium.
  • This invention relates to ion sources in which ions of alkali or alkaline earth metals or other low ionization potential substances are produced on a heated anode comprising a porous refractory metallic body which forms the closure for a supply of alkali or alkaline earth metal or its compound.
  • a heated anode comprising a porous refractory metallic body which forms the closure for a supply of alkali or alkaline earth metal or its compound.
  • the efficiency of such an ionic source is the higher as the work function of the porous metal is higher or, in other words, the difference between said work function and the ionization potential of the alkali or alkaline earth metal is greater. Hitherto, tungsten has been used for the porous metal.
  • the coating need be only from about 100 to 5,000 Angstrom units thick. Since the coating metal has a work function considerably higher than that of tungsten, the efiiciency of my ion source is higher than in the case where the coating is omitted from the tungsten body. On the other hand, only a very small amount of the coating material, which is very expensive, need be used, so that the cost thereof is minimal.
  • the coating may be applied by various means, such as by electrolytic means or by cathode sputtering or by spraying as described in the abovementioned copending application.
  • the figure shows an ion source according to my invention comprising a vacuum-tight envelope 1 which houses a molybdenum body or support 2 having, on the one hand, a space for a heating filament 3, and, on the other hand, a space for a supply 4 of rubidium compounds or other low ionization potential metal or substance.
  • Th supply 4 is closed by a densely-sintered porous tungsten body 5, covered with a thin layer 6 of rhenium.
  • an electrode 7 made negative relative to the body by means not shown, the ions generated on the surface 6 are accelerated towards an ion-optical system 8 and subsequently collected in an absorptive layer 9 on a collector 10.
  • rubidium compounds as explained, it is possible to use other alkali or alkaline earth metals.
  • the collector may be omitted and the envelope may be open, thus communicating with a further vacuum space in which the ions are used.
  • the ion source may form part of an ion propulsion engine. Instead of rhenium, iridium ruthenium and osmium may be used.
  • the thin, high work function metal, coating 6 is porous, as is required to enable the rubidium vapor and ions to flow through.
  • the coating is applied electrolytically or by cathode sputtering, by techniques well known in the art, in the thicknesses of about to 5000 Angstroms, the coating is inherently porous. If applied by spraying a slurry of fine powders dispersed in a suitable vehicle, thicker coatings which will also be porous can easily be obtained. After spraying, the powder coat is desirably sintered to the tungsten substrate.
  • the work functions for polycrystalline material vary from 5.1 to 5.6 v., thus most alkali metals will be ionized on them with good efficiency.
  • An ion source comprising a source of material exhibiting a low ionization potential, a porous refractory metal wall member closing off said source for ionizing the low ionization potential material which passes through its pores, and means for heating said porous member at a temperature at which electrons are stripped from thelow ionization potential material, said porous member comprising a preformed porous tungsten substrate with a porous coating deposited on its surface remote from the low ionization potential material source of a refractory metal having a higher work function than tungsten and selected from the group consisting of iridium, rhenium, ruthenium, and osmium, whereby said ion source exhibits a higher efiiciency than the comparable source without the deposited high work function metal coating.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Physical Vapour Deposition (AREA)
US410584A 1963-11-20 1964-11-12 Ion source having a high work function material coating the outer surface of the ionizer Expired - Lifetime US3382397A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL300777 1963-11-20
NL6401192A NL6401192A (enrdf_load_stackoverflow) 1964-02-12 1964-02-12

Publications (1)

Publication Number Publication Date
US3382397A true US3382397A (en) 1968-05-07

Family

ID=26641947

Family Applications (1)

Application Number Title Priority Date Filing Date
US410584A Expired - Lifetime US3382397A (en) 1963-11-20 1964-11-12 Ion source having a high work function material coating the outer surface of the ionizer

Country Status (4)

Country Link
US (1) US3382397A (enrdf_load_stackoverflow)
DE (1) DE1213540B (enrdf_load_stackoverflow)
GB (1) GB1020197A (enrdf_load_stackoverflow)
NL (1) NL300777A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3531679A (en) * 1967-02-22 1970-09-29 Siemens Ag Dispenser cathode,particularly an mk cathode having extended storage life
US4264813A (en) * 1979-06-29 1981-04-28 International Business Machines Corportion High intensity ion source using ionic conductors
US20220144556A1 (en) * 2019-03-08 2022-05-12 Hitachi High-Tech Corporation Conveying Device, Sample Analysis System and Sample Pretreatment Device Including the Conveying Device, And Method for Conveying Conveyance Object

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3467878A (en) * 1966-06-27 1969-09-16 Gen Electric Electron discharge device with arrangement for replenishing emissive material on a smooth cathode surface
US3852595A (en) * 1972-09-21 1974-12-03 Stanford Research Inst Multipoint field ionization source

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2754442A (en) * 1954-05-25 1956-07-10 Hartford Nat Bank & Trust Co Ion source
US2777086A (en) * 1952-07-26 1957-01-08 Westinghouse Electric Corp Cathode
US3119232A (en) * 1960-10-04 1964-01-28 Edward A Richley Rocket engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2777086A (en) * 1952-07-26 1957-01-08 Westinghouse Electric Corp Cathode
US2754442A (en) * 1954-05-25 1956-07-10 Hartford Nat Bank & Trust Co Ion source
US3119232A (en) * 1960-10-04 1964-01-28 Edward A Richley Rocket engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3531679A (en) * 1967-02-22 1970-09-29 Siemens Ag Dispenser cathode,particularly an mk cathode having extended storage life
US4264813A (en) * 1979-06-29 1981-04-28 International Business Machines Corportion High intensity ion source using ionic conductors
US20220144556A1 (en) * 2019-03-08 2022-05-12 Hitachi High-Tech Corporation Conveying Device, Sample Analysis System and Sample Pretreatment Device Including the Conveying Device, And Method for Conveying Conveyance Object

Also Published As

Publication number Publication date
DE1213540B (de) 1966-03-31
GB1020197A (en) 1966-02-16
NL300777A (enrdf_load_stackoverflow)

Similar Documents

Publication Publication Date Title
US2842706A (en) Cold cathode vacuum tube
Jacobs et al. The mechanism of field dependent secondary emission
Audi et al. Ion pumps
US3558966A (en) Directly heated dispenser cathode
US3373307A (en) Dispenser cathode
US3382397A (en) Ion source having a high work function material coating the outer surface of the ionizer
US3739216A (en) Secondary electron multipliers with single layer cermet coatings
US2988657A (en) Ion pump
US3573098A (en) Ion beam deposition unit
US2620287A (en) Secondary-electron-emitting surface
GB1309379A (en) Electric high-vacuum discharge tube
US2548514A (en) Process of producing secondaryelectron-emitting surfaces
US3240970A (en) Method and apparatus for replenishing hydrogen in a neutron generator
US3552124A (en) Ion thrustor accelerator system
CN110444463B (zh) 一种微电流铯离子源
US2147669A (en) Secondary electron emitting electrode
US3278789A (en) Cold emission cathode
US4038216A (en) Material and method of making secondary-electron emitters
US1897471A (en) Regulator
US3313969A (en) Charged particle deflecting apparatus having hemispherical electrodes
GB1207091A (en) Method of manufacturing and electronic discharge tube including a photocathode
US2760100A (en) Electric discharge tube
GB1105726A (en) Ionisation vacuum pump
US2171230A (en) Insulating coating
US1921066A (en) Cathode for electron discharge devices and method of making the same