EP0168777B1 - Tube à rayons X - Google Patents

Tube à rayons X Download PDF

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Publication number
EP0168777B1
EP0168777B1 EP19850108638 EP85108638A EP0168777B1 EP 0168777 B1 EP0168777 B1 EP 0168777B1 EP 19850108638 EP19850108638 EP 19850108638 EP 85108638 A EP85108638 A EP 85108638A EP 0168777 B1 EP0168777 B1 EP 0168777B1
Authority
EP
European Patent Office
Prior art keywords
cathode
ray tube
concave mirror
target
anode
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
EP19850108638
Other languages
German (de)
English (en)
Other versions
EP0168777A2 (fr
EP0168777A3 (en
Inventor
Hans-Erik Hjelmrodt
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.)
Scanray AS
Original Assignee
Scanray AS
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 Scanray AS filed Critical Scanray AS
Publication of EP0168777A2 publication Critical patent/EP0168777A2/fr
Publication of EP0168777A3 publication Critical patent/EP0168777A3/de
Application granted granted Critical
Publication of EP0168777B1 publication Critical patent/EP0168777B1/fr
Expired 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
    • H01J35/02—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J35/00—X-ray tubes
    • H01J35/02—Details
    • H01J35/04—Electrodes ; Mutual position thereof; Constructional adaptations therefor

Definitions

  • the invention relates to an X-ray tube of the type mentioned in the preamble of claim 1.
  • an X-ray tube of the type in question is known, in the evacuated piston of which a hot cathode surrounded by a grid, a hole anode and a target are arranged.
  • the hot cathode consists of a wire whose dimensions are large compared to the dimensions of the electron exit area.
  • a device for achieving an increased surface temperature is provided at the point at which the electric field between the anode and cathode reaches its highest value. In this way, the smallest possible expansion of the electron exit area on the cathode is to be achieved.
  • To generate the tiny spot of elevated temperature on the cathode u. a. also an external radiation exposure z. B.
  • the invention has for its object to provide an X-ray tube of the type in question, in which the disadvantages of the known X-ray tube are not available, so that such a temperature difference is achieved on the surface of the hot cathode without external radiation and without cooling measures that electrons predominantly from emerge from an extremely small area of the cathode in order to facilitate the focusing of the electron beam.
  • the radiation emanating from the hot cathode itself is focused by optical means onto a small spot on the surface of the hot cathode, so that there is an increase in temperature in relation to the surrounding area.
  • the concave mirror can be arranged in a simple and expedient manner coaxial to the electron beam going from the cathode through the hole of the hole anode to the target, in which case a hole is provided in the concave mirror through which the electron beam can pass. It is particularly expedient if, according to a development of the invention, the concave mirror is formed by the surface of the hole anode which faces the cathode and is preferably mirrored. This means that apart from a corresponding design of the hole anode and the mirroring, no additional measures are required in order to achieve the desired temperature increase in a narrowly limited focal point.
  • the cathode which is generally a V-shaped filament
  • the cathode is kept at such a temperature by electric heating that few electrons can escape from the surface.
  • the heat radiation is then sufficient, however, to achieve such an increase in temperature after focusing through the concave mirror on a fine point on the surface of the cathode that sufficient electrons can escape at this fine point.
  • the drawing shows, partially in section, an X-ray tube with a housing 1, which is connected to a line 2, which is connected to a pump, not shown, for lowering the pressure in the interior 3 of the X-ray tube.
  • a cathode 4 in the form of a small filament, which is bent in a V-shape and with its tip facing an anode 5 and a target 6.
  • a grid cap 7 is arranged in the region of the cathode 4, which projects into an opening 8 in the grid cap 7 and whose tip is approximately aligned with the front boundary of the opening 8. From this front boundary, the grille cap 7 widens in a conical surface 9.
  • anode 5 On the back of the hole anode 5 there is a tube 10 with a variable diameter, which is conductively connected to the hole anode 5.
  • the ochanode 5 runs through a hole 11 which continues into an interior 12 of the metallic tube 10.
  • a focusing coil 13 is arranged in the area of the metallic tube 10.
  • deflection coils 14 and 15 are provided, with which the electron beam can be deflected and which are of no further importance for the understanding of the invention.
  • the target 6 has an inclination to the axis 6 of the X-ray tube, indicated by a dash-dotted line, and is held in a holder 17 which is connected via pipes 18 and 19 to a cooling source (not shown) for the purpose of cooling the target.
  • a window 20 in the housing Radially next to the surface of the target 6 there is a window 20 in the housing through which X-rays emanating from the target 6 can emerge in the area between two dashed lines 21 and 22.
  • the angle between a central axis of the emerging x-rays, indicated by a dashed line 23, and the surface of the target 6 is approximately ⁇ 45 degrees.
  • the usual supply voltages are applied to the cathode 4, the grid cap 7 and the hole anode 5, which require no explanation here.
  • the hole anode 5 has on its side facing the cathode 4 a hollow surface 24 which is designed to be specular and shaped so that heat radiation is reflected by the cathode 4 and is focused on a fine point on the tip of the V-shaped cathode 4. At this focal point, the temperature rises such that electrons essentially only emerge at this fine point. This results in a very fine electron beam and consequently also a very small spot of impact of the electron beam on the target 6, so that an X-ray tube with a very fine focus is created. The fine electron beam also makes focusing easier.

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  • X-Ray Techniques (AREA)

Claims (4)

1. Tube à rayons X avec une cathode, avec une anode perforée, avec une cible et avec une installation pour diriger des radiations électromagnétiques sur la surface de la cathode tournée vers l'anode perforée, caractérisé en ce que l'installation est constituée par un miroir concave (24) qui est disposé dans la région de rayonnement thermique de la cathode (4) et dont le foyer est situé sur la surface de la cathode (4).
2. Tube à rayons X selon la revendication 1, caractérisé en ce que le miroir concave (24) est disposé coaxial au faisceau d'électrons allant de la cathode (4) à travers le trou (11) de l'anode perforée (5) jusqu'à la cible (6) et présente un trou dans la région du rayonnement d'électrons, comme l'anode perforée (5).
3. Tube à rayons X selon la revendication 2, caractérisé en ce que le miroir concave (24) est formé par la surface de l'anode perforée (5) tournée vers la cathode (4) métallisée.
4. Tube à rayons X selon la revendication 1, caractérisé en ce que la cathode (4) est une cathode chaude préchauffée électriquement, la température atteinte par le préchauffage étant sensiblement très voisine de la température nécessaire à l'émergence d'électrons, tandis que l'amenée de rayonnement électromagnétique par le miroir concave (24) sur la surface de la cathode (4) est dimensionnée de telle manière que les électrons émergent en ce point de manière prépondérante.
EP19850108638 1984-07-19 1985-07-11 Tube à rayons X Expired EP0168777B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19843426624 DE3426624A1 (de) 1984-07-19 1984-07-19 Roentgenroehre
DE3426624 1984-07-19

Publications (3)

Publication Number Publication Date
EP0168777A2 EP0168777A2 (fr) 1986-01-22
EP0168777A3 EP0168777A3 (en) 1987-08-19
EP0168777B1 true EP0168777B1 (fr) 1989-02-01

Family

ID=6241048

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850108638 Expired EP0168777B1 (fr) 1984-07-19 1985-07-11 Tube à rayons X

Country Status (2)

Country Link
EP (1) EP0168777B1 (fr)
DE (1) DE3426624A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0473228A3 (en) * 1990-08-28 1992-04-08 N.V. Philips' Gloeilampenfabrieken Improved anode for arc discharge devices
US5202910A (en) * 1990-08-28 1993-04-13 North American Philips Corporation Anode for arc discharge devices
KR101289502B1 (ko) 2005-10-07 2013-07-24 하마마츠 포토닉스 가부시키가이샤 Ｘ선관 및 비파괴 검사 장치

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE619621C (de) * 1933-09-06 1935-10-04 C H F Mueller Akt Ges Roentgenroehre mit durchlochter Hohlanode
US3388280A (en) * 1966-04-19 1968-06-11 Victor E. De Lucia Laser energized hot cathode type of electron discharge device
DE1614158A1 (de) * 1967-05-13 1971-04-29 Mueller C H F Gmbh Kathode fuer Roentgenroehre
DE2855905A1 (de) * 1978-12-23 1980-06-26 Licentia Gmbh Vorrichtung mit einer roentgenroehre
DE3222511C2 (de) * 1982-06-16 1985-08-29 Feinfocus Röntgensysteme GmbH, 3050 Wunstorf Feinfokus-Röntgenröhre
US4606061A (en) * 1983-12-28 1986-08-12 Tokyo Shibaura Denki Kabushiki Kaisha Light controlled x-ray scanner

Also Published As

Publication number Publication date
DE3426624A1 (de) 1986-01-30
DE3426624C2 (fr) 1987-04-23
EP0168777A2 (fr) 1986-01-22
EP0168777A3 (en) 1987-08-19

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