US2586771A - Process for making secondary emission electrodes - Google Patents

Process for making secondary emission electrodes Download PDF

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Publication number
US2586771A
US2586771A US660106A US66010646A US2586771A US 2586771 A US2586771 A US 2586771A US 660106 A US660106 A US 660106A US 66010646 A US66010646 A US 66010646A US 2586771 A US2586771 A US 2586771A
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Prior art keywords
electrode
secondary emission
bombardment
electrodes
electron
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US660106A
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English (en)
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Arditi Maurice
Walter D Urban
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International Standard Electric Corp
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International Standard Electric Corp
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Priority to FR956472D priority Critical patent/FR956472A/fr
Priority to BE474312D priority patent/BE474312A/xx
Application filed by International Standard Electric Corp filed Critical International Standard Electric Corp
Priority to US660106A priority patent/US2586771A/en
Priority to ES0178875A priority patent/ES178875A1/es
Application granted granted Critical
Publication of US2586771A publication Critical patent/US2586771A/en
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    • 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
    • H01J9/125—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes of secondary emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/32—Secondary emission electrodes

Definitions

  • FIG. 3 AFTER BOMBARDMENT BEFORE BOM BARDMENT VELOCITIES IN VOLTS WALTER URBAN A TTORNEY Feb. 26, 1952 M. ARDITI ETAL PROCESS FOR MAKING SECONDARY EMISSION ELECTRODES Filed April 6, 1946 FIG. 3
  • VELOCITIES 2 SHEETS-SHEET 2 BEFORE BOMBARDM ENT [0 r TL AFTER BOMBARDMENT a b a BEFORE BOMBARDMENT VELOCITIES IN VOLTS l I l I O 500 I000 I500 Z000 AFTER BOMBARDMENT INVENTORS IN VOLTS MAURICE ARDITI BY WALTER URBAN- A TTORNEY Patented Feb. 26, 1952 UNITED STATES PATENT OFFICE PROCESS FOR MAKING SECONDARY EMISSION ELECTRODES Delaware Application April 6, 1946, Serial No. 660,106 4 Claims. (Ci.- 316-22) The present invention relates to electronemitting electrodes and particularly to secondary emission electrodes.
  • An object of the present invention is the provision of a method for increasing the secondary electronic emission coefficient of secondary emission electrodes, particularly of the type treated in accordance with my aforementioned patents or patent application.
  • Fig. 1 is-a schematic diagram of an electron discharge device in which a secondary emission electrode is bombarded in accordance with the present invention and which device may thereafter be employed as a trigger tube or for various other purposes; and
  • Figs. 2, 3 and 4 are sets of curves indicating the results obtained from various secondary emission electrodes before and after bombardment in accordance with the present invention.
  • the electrode which may consist of one of the alloys mentioned hereinafter and also mentioned in the aforesaid patents or copending application, may be oxidized according to the processes mentioned in said patents or application.
  • the oxidized electrode is then mounted within an envelope which envelope is evacuated, and the electrode is then bombarded with a. high density, high voltage electron beam for a given period of time.
  • the electron density of the beam 2 during this bombardment is substantially higher than that to which the electrode is subjected during normal operation.
  • a secondary emission electrode were subjected to such a high density beam during operation thereof, it would after a given time lose the improved emission qualities characteristic of those electrodes treated according to the present invention.
  • the current employed was about milliamperes while normal operation current was about 1 to 2 milliamperes. The bombardment was carried out for a few seconds. When using smaller currents it has been found that the bombardment must be continued for a longer time, but under all circumstances the current employed was substantially greater than normal operation current.
  • the electron velocity of the electrons bombarding said electrode be about 500 volts or greater; thus in'processing the successive secondary emission electrodes of an electron multiplier it is desirable that the potential difference between successive electrodes be about 500 volts or greater, since the initial velocity of electrons from a secondary emission electrode is of the order of only 0 to 20 volts which is much too small for bombardment in accordance with the present invention.
  • beryllium copper electrode which consists of about 2% beryllium, 98% copper and 0.2% cobalt.
  • This electrode is cleaned and sealed into a hard glass tube, with a vigorous stream of nitrogen passing through the tube while sealing the tube to prevent oxidation of the electrode material.
  • After annealing the tube, which is sealed. it is evacuated by a suitable exhaust system which has provision for admitting oxygen. The tube is exhausted until the pressure is down to 15 microns or less, and the tube is heat treated with radio frequency current until all the gas has been liberated from the secondary emission electrode or approximately 600-700, and held for six (6) seconds only at this temperature.
  • the secondary emission electrode in accordance with one aspectof the present invention, it may be mounted in an evacuated tube, as for example the tube in which it is to be used, which may for example contain an electron gun I, whose cathode 2 is aged in any suitable manner (Fig. 1).
  • the secondary emission electrode 3 is bombarded for a few seconds with a current of about 60 milliamperes, the peak voltage on the secondary electrode being between 500 and 2,000 volts from a suitable source of potential 4.
  • the tube may include a collector electrode 5, which may be used in collecting the electrons during bombardment, in testing the secondary emission, and in normal operation.
  • the ratio N between the number of secondary electrons emitted and the number of primary electrons received is plotted along the vertical coordinate while the velocity of the primary electrons expressed in volts is plotted along the horizontal coordinate.
  • Curve 6 indicates the results obtained before bombardment and curve I indicates the result obtained after bombardment in accordance with the present invention.
  • alloy 61 SO which is comprised of 25% copper, .60% silicon, 25% magnesium, 25% chromium, with the remainder being aluminum, was likewise similarly oxidized and bombarded.
  • the curves 8 and 9 of Fig. 3 indicate the. results obtained before bombardment and after bombardment respectively.
  • a silver magnesium alloy which consists of silver and magnesium, oxidized according to said patents or said application and consisting for the most part of silver and an amount of magnesium in the alloy which is not critical and ranges between less than 1% to about 15% and which is oxidized (see Journal of Applied Physics, volume 12, September 1941, page 696) was similarly subjected to bombardment in accordance with the present invention.
  • Curves l and II of Fig. 4 indicate the results obtained before and after bombardment, respectively.
  • a secondary emission electrode comprised of an alloy for operation in an electron discharge device in which it is impinged upon by an electron stream having given normal operating densities
  • the steps comprising mounting the electrode in an evacuated container, oxidizing the surface of said electrode, and bombarding the oxidized electrode with an electron stream of high velocity having a relatively greater density than any of said normal operating densities.
  • a secondary emission electrode comprised of an alloy for operation in an electron discharge device in which it is impinged upon by an electron stream having given normal operating densities
  • the steps comprising mounting the electrode in an evacuated container, oxidizing the surface of said electrode. and bombarding the electrode for a limited period of the order of a few seconds duration with an electron stream of high velocity having a relatively greater density than any of said normal operating densities and having an electron velocity of about 500-2000 volts with respect to the cathode v 4.
  • a process for the manufacture of a vacuum tube electrode having an abnormally high secondary emission coefl'icient comprising selecting an alloy containing a predominant proportion of a metal selected from the class consisting of aluminium magnesium and beryllium, forming an electrode from said alloy, and heating said electrode in the presence of oxygen at a temperature such that a polished surface of the alloy would become slightly granular in appearance whereby the electrode is superficially oxidized, the improvements that comprise bombarding said superflcially oxidized electrode for a period of a few seconds with a high-density high-voltage electron stream, the density of said stream being substantially higher than that to which the electrode will be subjected in its intended use.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Cold Cathode And The Manufacture (AREA)
US660106A 1946-04-06 1946-04-06 Process for making secondary emission electrodes Expired - Lifetime US2586771A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
FR956472D FR956472A (en(2012)) 1946-04-06
BE474312D BE474312A (en(2012)) 1946-04-06
US660106A US2586771A (en) 1946-04-06 1946-04-06 Process for making secondary emission electrodes
ES0178875A ES178875A1 (es) 1946-04-06 1947-07-11 MEJORAS EN LOS PROCEDIMIENTOS PARA PREPARAR ELECTRODOS PARA EMISIoN SECUNDARIA

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US660106A US2586771A (en) 1946-04-06 1946-04-06 Process for making secondary emission electrodes

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US2586771A true US2586771A (en) 1952-02-26

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BE (1) BE474312A (en(2012))
ES (1) ES178875A1 (en(2012))
FR (1) FR956472A (en(2012))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2784123A (en) * 1952-05-01 1957-03-05 Rca Corp Secondary electron emitter and process of preparing same
US3713901A (en) * 1970-04-20 1973-01-30 Trw Inc Oxidation resistant refractory alloys
US4978885A (en) * 1989-03-02 1990-12-18 Galileo Electro-Optics Corporation Electron multipliers with reduced ion feedback
US6239549B1 (en) 1998-01-09 2001-05-29 Burle Technologies, Inc. Electron multiplier electron source and ionization source using it

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2189972A (en) * 1938-04-22 1940-02-13 Csf Secondary electron emitter
FR862488A (fr) * 1939-08-29 1941-03-07 Materiel Telephonique électrodes à émission électronique
US2237242A (en) * 1938-01-05 1941-04-01 Univ Illinois Phototube
GB559591A (en) * 1942-07-17 1944-02-25 Int Standard Electric Corp Improvements relating to secondary electron emissive electrodes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2237242A (en) * 1938-01-05 1941-04-01 Univ Illinois Phototube
US2189972A (en) * 1938-04-22 1940-02-13 Csf Secondary electron emitter
FR862488A (fr) * 1939-08-29 1941-03-07 Materiel Telephonique électrodes à émission électronique
GB559591A (en) * 1942-07-17 1944-02-25 Int Standard Electric Corp Improvements relating to secondary electron emissive electrodes

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2784123A (en) * 1952-05-01 1957-03-05 Rca Corp Secondary electron emitter and process of preparing same
US3713901A (en) * 1970-04-20 1973-01-30 Trw Inc Oxidation resistant refractory alloys
US4978885A (en) * 1989-03-02 1990-12-18 Galileo Electro-Optics Corporation Electron multipliers with reduced ion feedback
US6239549B1 (en) 1998-01-09 2001-05-29 Burle Technologies, Inc. Electron multiplier electron source and ionization source using it

Also Published As

Publication number Publication date
ES178875A1 (es) 1947-09-16
BE474312A (en(2012))
FR956472A (en(2012)) 1950-02-02

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