US2206710A - Pool-type X-ray tube - Google Patents

Pool-type X-ray tube Download PDF

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Publication number
US2206710A
US2206710A US227927A US22792738A US2206710A US 2206710 A US2206710 A US 2206710A US 227927 A US227927 A US 227927A US 22792738 A US22792738 A US 22792738A US 2206710 A US2206710 A US 2206710A
Authority
US
United States
Prior art keywords
tube
discharge
cathode
anode
ray
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
US227927A
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English (en)
Inventor
Tonks Lowi
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 BE436501D priority Critical patent/BE436501A/xx
Application filed by General Electric Co filed Critical General Electric Co
Priority to US227927A priority patent/US2206710A/en
Priority to DEL98896D priority patent/DE766054C/de
Priority to FR859683D priority patent/FR859683A/fr
Priority to GB25011/39A priority patent/GB532479A/en
Application granted granted Critical
Publication of US2206710A publication Critical patent/US2206710A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/22—X-ray tubes specially designed for passing a very high current for a very short time, e.g. for flash operation

Definitions

  • the present mvention relates to improvements in X-ray devices.
  • Fig. 1 illustrates an X-ray apparatus suitably embodying the invention
  • Figs. 2 and 3 are graphical representations useful in explaining the invention
  • Fig. 4 illustrates an 50 alternative embodiment.
  • a discharge device comprising a sealed envelope Ill consisting of a glass cylinder which is closed at its lower end by means of a metallic header I I. 'I'his header is in contact with a mercury pool (Cl. Z-98) cathode I2 and supports a cooling coil I3 which serves during operation to limit the mercury vapor pressure. l
  • a keep-alive electrode I4 Associated with the cathode there is provided a keep-alive electrode I4. suitably of graphite. which is adapted to maintain a holding arc to the cathode surface.
  • an immersion ignitor of known typewhich functions when energized to produce a cathode spot on the mercury surface.
  • a starting circuit comprising a current source I8 and a control switch I9 may be used to energize the electrode I6 when it is desired to start the tube in operation.
  • 'I'he holding-arc cathode spot may be confined to a desired portion of the cathode surface by means of a ring 2l of cathode-spot-anchoring material, for example, molybdenum.
  • a resistor 22 in series with the anode I4 serves to limit the holding-arc current to a desired value.
  • anode structure which is shown as comprising a heavy shaftportion 2li cooled by means of a uid circulating system having an inlet 25a and an outlet 26.
  • the anode terminates in a portion 25 28 which has a central opening 29 therein and which incorporates a discharge receiving member or target which is constituted of a material capable of ⁇ eective X-ray emission when bombarded by high velocity electrons. Materials of high atomic weight are suitable for this use but I consider tungsten to be a preferred example because of its superior ability to withstand heat.
  • the target 30 has its surface inclined to the axis of the tube so as to facilitate the projection of X-rays therefrom to a region outside of the tube. Such projection is further aided by the provision of a lateral opening 32 provided in the anode portion 28.
  • means are provided for narrowly restricting a portion of the discharge path between the main anode and the cathode.
  • such means is shown as comprising the combination of a heavy plate 35 having a central opening 36 therein and a lighter plate 39, positioned over the opening 3B and itself having an opening 40 of relatively small diameter, preferably from about one-quarter to one-half inch.
  • a cooling means such as is indicated by the Vcooling coil 4I secured peripherally to the plate.
  • This source need have only a relatively small voltage, say several hundred volts, and is connected across the tube through a circuit which includes a current limiting resistance 43 and an inductance 44.
  • a potential-limiting spark gap 4l is connected across the tube terminals in series with a resistance 48.
  • An ammeter B9 is provided for measuring the current supplied to the tube.
  • the initial discharge may take the form of an arc discharge having a relatively low potential drop. Under these conditions the current starts to build up approximately linearly as indicated by the portion A of the graphical representation of Fig. 2. Its rate of increase is limited primarily by the inductance 44. As soon as a certain critical value Bof current is attained, however, the
  • shielding members 52- and 53 In order properly to conilne the ionization produced by the high velocity electrons in the vicinity oi.' the anode, there are provided shielding members 52- and 53.
  • An additional shielding member 54 serves to protect the sealed joint between the envelope and the plate from high potentialgradients which might otherwise cause puncturing of the tube at this point.
  • Such medium may comprise a xed gas (rather than mercury vapor as in the construction above described) or it may comprise a mixture of a gas and a vapor.
  • the mercury vapor pressure is preferably maintained in the range oi' from, a fraction of a micron to several microns.
  • the equivalent pressure will be many times higher.
  • the appropriate pressure will be at least from 10 to 100 times higher than the pressure considered appropriate in the old style cold cathode gas-containing X-ray tubes.
  • Such tubes would be entirely inoperative if supplied with gas or vapor at the pressures utilized in the tubes of my present invention;
  • An X-ray producing device comprising an envelope enclosing a readily ionizable medium at a pressure suiiicient to support an arc discharge, an anode and a cathode withinrthe envelope, said anode having at least a portion of its discharge-receiving surface constituted of a material which is an effective X-ray emitter when bombarded by high potential electrons, and means narrowly confining a portion of the discharge path between the anode and cathode, whereby X-ray producing potentials may be developed within the tube as a result of a constriction eiiect occurring during the passage of a discharge therethrough.
  • An X-ray tubel comprising a cathode, an anode, an ionizable operating medium at a pressure sufiicient to support an arc discharge and means narrowly confining the discharge space between the anode and cathode whereby X-rayproducing potentials may be developed within the tube as a result of a constriction eiect occurring during the passage of a. discharge therethrough,
  • the said anode' having at least a portion of its discharge-receiving surface arrangedto facilitate the projection of X-rays therefrom to a region outside the tube.
  • an anode capable of effective X-ray emission upon bombardment by high velocity electrons
  • a mercury pool cathode one or more barriers separating the anode and cathode, said barriers being provided with restricted openings to permit thepassage of a discharge therethrough
  • circuit means connecting with the anode and cathode, said circuit means including inductance of suflicient value to permit thedevelopment of an X-ray producing potential as a. result of constriction effects occurring in said restricted opening during passage of discharge current therethrough.
  • An X-ray tube including a mercury pool cathode, means for maintaining a holding arc to the cathode surface, an anode having a tungsten discharge-receiving surface which is angu larly inclined with respect to the axis of the tube tofacilitate the projection of X-rays therefrom ⁇ and a barrier separatingthe anode and cathode,
  • said barrier having a restricted opening Vwhereby an X-ray-producing potential may exist within the tube during a discharge period as a result of constriction effects ocurring in said opening.

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  • X-Ray Techniques (AREA)
US227927A 1938-09-01 1938-09-01 Pool-type X-ray tube Expired - Lifetime US2206710A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE436501D BE436501A (enrdf_load_stackoverflow) 1938-09-01
US227927A US2206710A (en) 1938-09-01 1938-09-01 Pool-type X-ray tube
DEL98896D DE766054C (de) 1938-09-01 1939-08-26 Gas- oder dampfgefuellte Roentgenroehre mit fluessiger Kathode
FR859683D FR859683A (fr) 1938-09-01 1939-08-30 Tubes à rayons x avec pression gazeuse élevée
GB25011/39A GB532479A (en) 1938-09-01 1939-08-31 Improvements in and relating to x-ray apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US227927A US2206710A (en) 1938-09-01 1938-09-01 Pool-type X-ray tube

Publications (1)

Publication Number Publication Date
US2206710A true US2206710A (en) 1940-07-02

Family

ID=22855014

Family Applications (1)

Application Number Title Priority Date Filing Date
US227927A Expired - Lifetime US2206710A (en) 1938-09-01 1938-09-01 Pool-type X-ray tube

Country Status (5)

Country Link
US (1) US2206710A (enrdf_load_stackoverflow)
BE (1) BE436501A (enrdf_load_stackoverflow)
DE (1) DE766054C (enrdf_load_stackoverflow)
FR (1) FR859683A (enrdf_load_stackoverflow)
GB (1) GB532479A (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428616A (en) * 1943-11-02 1947-10-07 Philco Corp Electrical protective device
US2429217A (en) * 1942-05-07 1947-10-21 Electronized Chem Corp Device for treatment of matters with high-speed electrons
US2438191A (en) * 1943-06-19 1948-03-23 Westinghouse Electric Corp High-pressure modulator tube
US2508529A (en) * 1948-03-06 1950-05-23 Bell Telephone Labor Inc Gaseous electronic discharge device
US2840632A (en) * 1952-06-02 1958-06-24 Henry W Parker Cathode spot television receiving system
US3254255A (en) * 1963-01-04 1966-05-31 Westinghouse Electric Corp Mercury vapor discharge device having a novel brazing alloy

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE566669C (de) * 1925-05-30 1932-12-19 Siemens & Halske Akt Ges Einrichtung zur intermittierenden Unterbrechung elektrischer Stroeme
CH161961A (de) * 1929-08-13 1933-05-31 Aeg Metalldampfgleichrichter mit Anodenschutzrohr.
CH170211A (de) * 1932-03-03 1934-06-30 Meaf Mach En Apparaten Fab Nv Entladeröhre mit Gas- oder Dampffüllung.
AT143570B (de) * 1934-06-26 1935-11-25 Meaf Mach En Apparaten Fab Nv Vakuumentladeröhre.

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429217A (en) * 1942-05-07 1947-10-21 Electronized Chem Corp Device for treatment of matters with high-speed electrons
US2438191A (en) * 1943-06-19 1948-03-23 Westinghouse Electric Corp High-pressure modulator tube
US2428616A (en) * 1943-11-02 1947-10-07 Philco Corp Electrical protective device
US2508529A (en) * 1948-03-06 1950-05-23 Bell Telephone Labor Inc Gaseous electronic discharge device
US2840632A (en) * 1952-06-02 1958-06-24 Henry W Parker Cathode spot television receiving system
US3254255A (en) * 1963-01-04 1966-05-31 Westinghouse Electric Corp Mercury vapor discharge device having a novel brazing alloy

Also Published As

Publication number Publication date
GB532479A (en) 1941-01-24
BE436501A (enrdf_load_stackoverflow)
FR859683A (fr) 1940-12-24
DE766054C (de) 1952-12-22

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