US1907508A - Thermionic apparatus - Google Patents

Thermionic apparatus Download PDF

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Publication number
US1907508A
US1907508A US404609A US40460929A US1907508A US 1907508 A US1907508 A US 1907508A US 404609 A US404609 A US 404609A US 40460929 A US40460929 A US 40460929A US 1907508 A US1907508 A US 1907508A
Authority
US
United States
Prior art keywords
cathode
switch
regulator
focal
current
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
US404609A
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English (en)
Inventor
William D Coolidge
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.)
General Electric Co
Original Assignee
General Electric Co
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 US393819A priority Critical patent/US1946286A/en
Application filed by General Electric Co filed Critical General Electric Co
Priority to US404609A priority patent/US1907508A/en
Priority to GB28091/30A priority patent/GB355978A/en
Priority to FR704038D priority patent/FR704038A/fr
Priority to FR39185D priority patent/FR39185E/fr
Priority to GB32540/30A priority patent/GB366473A/en
Priority to BE374674D priority patent/BE374674A/fr
Priority to US610866A priority patent/US1946288A/en
Application granted granted Critical
Publication of US1907508A publication Critical patent/US1907508A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/52—Target size or shape; Direction of electron beam, e.g. in tubes with one anode and more than one cathode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/14—Arrangements for concentrating, focusing, or directing the cathode ray
    • H01J35/147—Spot size control

Definitions

  • the present invention relates to thermionic devices, such, for example, as X-ray tubes, provided with a plurality of cathodes, which are capable of being used interchangeably.
  • said cathodes may tion in order to avoid overheating of the target at the focal spot.
  • means are provided for controlling the current in the heating circuits of the respective cathode circuits of an X-ray tube, or.other thermionic device, the setting of said control means being. sointerlocked with switching means for selectively exciting the cathodes of the discharge tube that a change from one cathode to another automatically fixes the setting of regulating means for the cathode selected for operation.
  • FIG. 1 of the drawing shows somewhat diagrammatically an X-ray apparatus embodying my invention
  • Fig.2 illustrates a modification adapted particularly for operation ,in connection with oil-immersed X-ray devices
  • Fig. 3 is a detail View of a cathode structure which is employed in an X-ray tube used in my improved apparatus.
  • the system illustrated in Fig. 1 includes.
  • thermionic X-ray device comprising a bulbous container 2, containing a cathode structure 3 and an anode or target 4, stem 5 of which leads to an external radiator or heat dlsslpator 6.
  • the cathode structure 3, as shown in Fig. 3 comprises a cup-shaped focusing device 7 in which are provided spirally Wound filaments 8 and 9. These filaments have separate supply conductors 11 .and 10 respectively and a common return conductor 12.
  • the filaments are so positioned within the focusing device 7 that when either filament is heated to an electron:emitting temperature, that electrons emitted by it, (also 7 known as cathode rays) will be projected 5 upon a target 14 of highly refractory metal, such for example as tungsten, which forms part of the anode 5.
  • the electrons emitted from either ofthe filaments 8 or 9 are caused to impinge upon a focal 'spot on the target, the size of the focal spots depending upon the position of the filaments 8 and 9 within the focusing cup 7.
  • the size and excitation of the filaments 8 and 9 are so chosen that a relatively small electron current is caused to be emitted by the filament 8 and a larger current is caused to be emitted by the filament 9, thus permitting different X-ray outputs to be obtained from the X-ray tube.
  • the electrostatic focusing effect of the device 7 causes the cathode rays fromthe respective filaments to be focused on focal spots of correspondingly different areas. To secure maximum definition the focal spot should be as small as practicable without overheating the anode'metal at the focal spot during a normal period of operation.
  • Heating current for the cathode filament is obtained from the secondary of theatransformer 15, the primary of which is connected to the supply mains 16.
  • Either one of the filaments 8 or 9 may be connected in circuit with the transformer 15 by aselector switch 17, that is, when the selector switch is moved to the. left to the contact 18 so as to complete the circuit of the conductor 10, heating current will flow from the secondary of the transformer 15, through the conductor 10, through the filament-9, returning through the conductor 12,
  • the resistance 19 is caused to be shortcircuited periodically by the vibrations of a magnetic member or armature 33 which is juxtaposed to the core 34 of the windings 25 and 26.
  • the vibrations of this armature opens and closes contacts 35 in a circuit 36 shunting the resistance 19.
  • the relative periods of make and break of the contacts 35 determine the effect of the resistance 19 in the respective cathode circuits.
  • a regulator of the form here shown is more fully described in U. S. Letters Patent No.
  • the switches 17 and 27 are connected to one another by an interlock member 37.
  • the setting ofthe accuses X-ray tube can be shifted from one setting to another with the assurance that whenever the focus of the X-ray is changed to provide a smaller focal spot for sharper definition or for any other reason that the space current in the X-ray tube at the same time will be decreased and maintained at a lower value.
  • the re ulator is connected in the primary circult of transformers 40 and 41, the secondary circuits; of which are respectively connected to the cathode supply conductors 10, 11 and 12.
  • the windings 42 and 43 of the regulator 44 are connected in series with the secondary windings 45 and 45 of the transformer 46 which supplies high potential operating current by the conductors 47 and 48 to the X-ray device.
  • a regulable resistance 54 may be inserted in shunt with the primary winding'of transformer 40 to permit of hand adjustment of the value of the heating current.
  • a similar resistance 55 is inserted in shunt with the primary winding of the transformer 41.
  • the arrangement shown in this figure is particularly suitable for operation with a device in which the X-ray tube as well as the high potential transformer 46 and the low potential filament transformers 40 and 41 are'all contained within an enclosure or tank 49 which contains a body of oil, or other suitable insulatin fluid.
  • the cathode heating transformer 40 When the switch 17 is moved to the left in contact with a conductor 56, the cathode heating transformer 40 is energized, thereby suppling heating current to the cathode filament 9.
  • thermionic discharge device having a plurality of cathodes, energizing circuits respectively connected to said cathodes, a regulator for maintaining the current in said circuits substantially constant at difl'erent selected values, and means for automatically changing the setting of said regulator whenever a change in the excitatlon of said energizing circuits is efi'ected.
  • circuit means including a selector switch for creating in said device electronic discharges of unlike values for different focal settings, a
  • regulator for maintaining such electronic discharges substantially constant at selected values, and means including aselector switch interlocked with said first-mentioned switch for changing the setting of said regulator to correspond with a selected electronic discharge.

Landscapes

  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • X-Ray Techniques (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Particle Accelerators (AREA)
  • Microwave Tubes (AREA)
  • Cold Cathode And The Manufacture (AREA)
US404609A 1929-09-19 1929-11-04 Thermionic apparatus Expired - Lifetime US1907508A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US393819A US1946286A (en) 1929-09-19 1929-09-19 X-ray equipment
US404609A US1907508A (en) 1929-11-04 1929-11-04 Thermionic apparatus
FR704038D FR704038A (fr) 1929-11-04 1930-09-19 Perfectionnements aux appareils et aux équipements pour rayons x.
GB28091/30A GB355978A (enrdf_load_stackoverflow) 1929-11-04 1930-09-19
FR39185D FR39185E (fr) 1929-11-04 1930-10-24 Perfectionnements aux appareils et aux équipements pour rayons x
GB32540/30A GB366473A (en) 1929-11-04 1930-10-29 Improvements in and relating to x-ray apparatus
BE374674D BE374674A (fr) 1929-11-04 1930-11-04 perfectionnements aux appareils et equipements pour rayons x
US610866A US1946288A (en) 1929-09-19 1932-05-12 Electron discharge device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US404609A US1907508A (en) 1929-11-04 1929-11-04 Thermionic apparatus

Publications (1)

Publication Number Publication Date
US1907508A true US1907508A (en) 1933-05-09

Family

ID=23600306

Family Applications (1)

Application Number Title Priority Date Filing Date
US404609A Expired - Lifetime US1907508A (en) 1929-09-19 1929-11-04 Thermionic apparatus

Country Status (3)

Country Link
US (1) US1907508A (enrdf_load_stackoverflow)
BE (1) BE374674A (enrdf_load_stackoverflow)
GB (2) GB355978A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2492304A (en) * 1948-05-08 1949-12-27 Westinghouse Electric Corp Tandem x-ray tube stabilizer
US2691735A (en) * 1951-06-15 1954-10-12 Hartford Nat Bank & Trust Co X-ray tube
US2712075A (en) * 1945-01-26 1955-06-28 Bevis Murray Automatic emission control circuit
US2900542A (en) * 1954-09-22 1959-08-18 Harry B Mceuen X-ray apparatus
US3110810A (en) * 1958-10-30 1963-11-12 Philips Corp Device for optionally switching on either of two filament cathodes of an X-ray tube

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2712075A (en) * 1945-01-26 1955-06-28 Bevis Murray Automatic emission control circuit
US2492304A (en) * 1948-05-08 1949-12-27 Westinghouse Electric Corp Tandem x-ray tube stabilizer
US2691735A (en) * 1951-06-15 1954-10-12 Hartford Nat Bank & Trust Co X-ray tube
US2900542A (en) * 1954-09-22 1959-08-18 Harry B Mceuen X-ray apparatus
US3110810A (en) * 1958-10-30 1963-11-12 Philips Corp Device for optionally switching on either of two filament cathodes of an X-ray tube

Also Published As

Publication number Publication date
GB355978A (enrdf_load_stackoverflow) 1931-09-03
GB366473A (en) 1932-01-29
BE374674A (fr) 1930-12-31

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