GB981480A - A photo-electric cathode and method for its manufacture - Google Patents

A photo-electric cathode and method for its manufacture

Info

Publication number
GB981480A
GB981480A GB4183163A GB4183163A GB981480A GB 981480 A GB981480 A GB 981480A GB 4183163 A GB4183163 A GB 4183163A GB 4183163 A GB4183163 A GB 4183163A GB 981480 A GB981480 A GB 981480A
Authority
GB
United Kingdom
Prior art keywords
layer
tungsten
envelope
photo
cathode
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
Application number
GB4183163A
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.)
Compagnie Francaise Thomson Houston SA
Original Assignee
Compagnie Francaise Thomson Houston SA
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
Application filed by Compagnie Francaise Thomson Houston SA filed Critical Compagnie Francaise Thomson Houston SA
Publication of GB981480A publication Critical patent/GB981480A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/38—Photoelectric screens; Charge-storage screens not using charge storage, e.g. photo-emissive screen, extended cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/02—Main electrodes
    • H01J1/34—Photo-emissive cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/34—Photoemissive electrodes
    • H01J2201/342—Cathodes
    • H01J2201/3421—Composition of the emitting surface
    • H01J2201/3426—Alkaline metal compounds, e.g. Na-K-Sb

Abstract

A photo-cathode, Fig. 1, comprises a glass surface 1 having a first layer 2 thereon which comprises slightly oxidized tungsten, molybdenum, manganese, chromium or cobalt and a second layer 4 on the first layer comprising antimony and a plurality of alkali metals. Alkali metals mentioned include potassium, sodium and caesium. An image intensifying tube temporarily provided with means for depositing the two layers of the photo-cathode is shown in Fig. 2. Inside a glass envelope 10 are electrodes 11, 12, 13, a fluorescent screen 14 and a disc 15 to cover the aperture in electrode 12 while the photo-cathode is being formed. The photo-cathode 23 is formed by evaporating on the glass envelope 10 a first layer of tungsten from a tungsten filament 18 fixed to two rigid conductors 19 connected by sliding contacts 20 to terminals 21 in a glass tube 16, including soft steel parts 22 so that filament 18 may be moved along tube 16 by an external magnet (not shown). In one method, envelope 10 is evacuated through tube 17 to a pressure between 5.10-3 and 5.10-5 Torr, filament 18 is moved to a central position and heated by passing current through it which causes the tungsten to evaporate. During this operation a small portion of the tungsten layer oxidizes. In a second method, the tungsten is evaporated with an air pressure below 10-6 Torr. After deposition of the layer, the tungsten is partially oxidized by admitting oxygen into the envelope until the pressure is from 10-3 to 10-4 Torr, and releasing an electrical discharge between one of terminals 21 and terminal 24 connected to layer 23. Filament 18 is then withdrawn from the envelope and the vacuum increased to 10-6 Torr. The second layer is then deposited by evaporation of successive layers of antimony from antimony rod 26, potassium from evaporator 27 at an envelope temperature of 160-200 DEG C., sodium from evaporator 28, and caesium from evaporator <PICT:0981480/C6-C7/1> <PICT:0981480/C6-C7/2> 29, the temperature for the evaporation of caesium being 140-160 DEG C.
GB4183163A 1962-10-23 1963-10-23 A photo-electric cathode and method for its manufacture Expired GB981480A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR913118A FR1345063A (en) 1962-10-23 1962-10-23 Photoelectric cathode

Publications (1)

Publication Number Publication Date
GB981480A true GB981480A (en) 1965-01-27

Family

ID=8789280

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4183163A Expired GB981480A (en) 1962-10-23 1963-10-23 A photo-electric cathode and method for its manufacture

Country Status (2)

Country Link
FR (1) FR1345063A (en)
GB (1) GB981480A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2157884A (en) * 1981-11-30 1985-10-30 Thermo Electron Corp Photoemissive cathode for high current density photoelectron generators

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2498321A1 (en) * 1981-01-21 1982-07-23 Labo Electronique Physique PHOTOELECTRIC DETECTION STRUCTURE
JP2500209B2 (en) * 1991-09-11 1996-05-29 浜松ホトニクス株式会社 Reflective photocathode and photomultiplier tube

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2157884A (en) * 1981-11-30 1985-10-30 Thermo Electron Corp Photoemissive cathode for high current density photoelectron generators

Also Published As

Publication number Publication date
FR1345063A (en) 1963-12-06

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