EP0032385B1 - Cathodes arrangement for an x-ray tube - Google Patents

Cathodes arrangement for an x-ray tube Download PDF

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Publication number
EP0032385B1
EP0032385B1 EP81100096A EP81100096A EP0032385B1 EP 0032385 B1 EP0032385 B1 EP 0032385B1 EP 81100096 A EP81100096 A EP 81100096A EP 81100096 A EP81100096 A EP 81100096A EP 0032385 B1 EP0032385 B1 EP 0032385B1
Authority
EP
European Patent Office
Prior art keywords
cathode
ray tube
arrangement
heating coil
longitudinal direction
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
EP81100096A
Other languages
German (de)
French (fr)
Other versions
EP0032385A1 (en
Inventor
Kurt Dr.-Ing. Franke
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.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Priority to AT81100096T priority Critical patent/ATE3797T1/en
Publication of EP0032385A1 publication Critical patent/EP0032385A1/en
Application granted granted Critical
Publication of EP0032385B1 publication Critical patent/EP0032385B1/en
Expired legal-status Critical Current

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    • 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
    • H01J35/06—Cathodes
    • H01J35/066—Details of electron optical components, e.g. cathode cups

Definitions

  • the invention relates to a cathode arrangement for an X-ray tube with a cathode pot for electron focusing, which has a groove-like depression for the heating coil.
  • a cathode arrangement of this type is known in which two heating coils located in the groove-like recess of the cathode pot are surrounded by metallic screens.
  • the diaphragm sides can be applied separately to independently adjustable voltages. These voltages set the size of the focal spot on the anode of the X-ray tube. The potential at the diaphragms determines this size.
  • the influence on the expansion of the focal spot via the potentials on the diaphragms is, however, limited. In practice, it is only possible to determine the sharpness of the focal spot in this way.
  • the invention has for its object to provide a cathode arrangement of the type mentioned, which makes it possible to influence the extent of the focal spot.
  • the cathode pot is divided approximately perpendicular to the longitudinal direction of the heating coil into several, mutually insulated parts to which separate control potentials can be supplied.
  • a different grid potential can be fed to several parts of the cathode pot.
  • the extent of the rectangular focal spot can be influenced both in length and in width by means of these grid potentials.
  • Fig. 1 denotes the glass bulb of an X-ray tube 2.
  • a cathode arrangement 3 is provided at one end and an anode arrangement 4 at the opposite end.
  • the cathode arrangement 3 has a cathode pot 6 on its housing 5.
  • the heating coil 7 is located in a groove-like recess 8 of the cathode pot 6, which is used for focusing.
  • the heating coil 7 is opposite the anode 9, which is designed as a rotating anode.
  • To operate the heating coil 7, a heating voltage is applied to the heating coil 7 via lines 10 and 11.
  • the high voltage is fed to the X-ray tube via a line 12 and a connecting piece 13 located at the anode-side end of the X-ray tube 2, which accelerates the electrons emerging from the heating coil 7 in accordance with line 17.
  • the cathode pot 6 is divided perpendicularly to the longitudinal direction of the heating coil 7 into several, namely into three parts 14, 15, 16 which are insulated from one another.
  • the parts 14, 15, 16 of the cathode pot 6 can be supplied with separate control potentials. This makes it possible to influence the dimensions of the focus both in the longitudinal and in the transverse direction via these control potentials.
  • the part 15 is supplied with the control potential Ug1.
  • the tax potential Ug2 lies on parts 14 and 16.
  • the cathode pot 6 is divided perpendicularly to the longitudinal direction of the heating coil 7 into three parts 14, 15, 16, the thickness of which is approximately the same in this longitudinal direction.

Abstract

In an exemplary embodiment, a cathode cup for electron focusing has a groove-like cavity for the heater coil. The cathode cup is subdivided, approximately perpendicularly to the longitudinal direction of the heater coil into several parts which are insulated from one another, to which separate control potentials can be supplied.

Description

Die Erfindung betrifft eine Kathodenanordnung für eine Röntgenröhre mit einem Kathodentopf zur Elektronenfokussierung, der eine nutartige Vertiefung für die Heizwendel aufweist.The invention relates to a cathode arrangement for an X-ray tube with a cathode pot for electron focusing, which has a groove-like depression for the heating coil.

Durch die DE-A-2 249 365 ist eine Kathodenanordnung dieser Art bekannt, bei der zwei in der nutartigen Vertiefung des Kathodentopfes liegende Heizwendeln von metallischen Blenden umgeben sind. Die Blendenseiten sind dabei voneinander getrennt an unabhängig regelbare Spannungen anlegbar. Durch diese Spannungen wird die Größe des Brennfleckes auf der Anode der Röntgenröhre eingestellt. Das Potential an den Blenden bestimmt nämlich diese Größe. Der Beeinflussung der Ausdehnung des Brennflekkes über die Potentiale an den Blenden sind dabei jedoch enge Grenzen gesetzt. Praktisch ist es nur möglich, die Schärfe des Brennfleckes auf diese Weise festzulegen.From DE-A-2 249 365 a cathode arrangement of this type is known in which two heating coils located in the groove-like recess of the cathode pot are surrounded by metallic screens. The diaphragm sides can be applied separately to independently adjustable voltages. These voltages set the size of the focal spot on the anode of the X-ray tube. The potential at the diaphragms determines this size. The influence on the expansion of the focal spot via the potentials on the diaphragms is, however, limited. In practice, it is only possible to determine the sharpness of the focal spot in this way.

Der Erfindung liegt die Aufgabe zugrunde, eine Kathodenanordnung der eingangs genannten Art zu schaffen, die es erlaubt, die Ausdehnung des Brennfleckes beeinflussen zu können.The invention has for its object to provide a cathode arrangement of the type mentioned, which makes it possible to influence the extent of the focal spot.

Diese Aufgabe ist erfindungsgemäß dadurch gelöst, daß der Kathodentopf etwa senkrecht zur Längsrichtung der Heizwendel in mehrere, voneinander isolierte Teile aufgeteilt ist, denen getrennte Steuerpotentiale zuführbar sind. Bei der erfindungsgemäßen Kathodenanordnung ist mehreren Teilen des Kathodentopfes ein jeweils unterschiedliches Gitterpotential zuführbar. Über diese Gitterpotentiale ist dabei die Ausdehnung des rechteckförmigen Brennfleckes sowohl in der Länge als auch in der Breite beeinflußbar.This object is achieved in that the cathode pot is divided approximately perpendicular to the longitudinal direction of the heating coil into several, mutually insulated parts to which separate control potentials can be supplied. In the cathode arrangement according to the invention, a different grid potential can be fed to several parts of the cathode pot. The extent of the rectangular focal spot can be influenced both in length and in width by means of these grid potentials.

Die Erfindung ist nachfolgend anhand eines in der Zeichnung dargestellten Ausführungsbeispiels näher erläutert. Es zeigt

  • Fig. 1 eine Röntgenröhre mit einer Kathodenanordnung nach der Erfindung,
  • Fig.2 eine Ansicht der für die Erfindung wesentlichen Teile der Kathodenanordnung der Röntgenröhre gemäß Fig. 1 in vergrößertem Maßstab und um 90° verdreht und
  • Fig. 3 eine Draufsicht auf die Kathodenanordnung gemäß Fig.2, also eine Ansicht der Kathodenanordnung von der Anode aus gesehen.
The invention is explained below with reference to an embodiment shown in the drawing. It shows
  • 1 shows an X-ray tube with a cathode arrangement according to the invention,
  • 2 shows a view of the parts of the cathode arrangement of the X-ray tube according to FIG. 1 which are essential for the invention, on an enlarged scale and rotated by 90 ° and
  • 3 shows a plan view of the cathode arrangement according to FIG. 2, that is to say a view of the cathode arrangement from the anode.

In der Fig. 1 ist mit 1 der Glaskolben einer Röntgenröhre 2 bezeichnet. Im Innern des Kolbens 1 ist an einem Ende eine Kathodenanordnung 3 und am gegenüberliegenden Ende eine Anodenanordnung 4 vorgesehen. Die Kathodenanordnung 3 weist an ihrem Gehäuse 5 einen Kathodentopf 6 auf. Dieser enthält eine Heizwendel 7, die in den Figuren nur schematisch dargestellt ist. Die Heizwendel 7 liegt in einer nutartigen Vertiefung 8 des Kathodentopfes 6, der zur Fokussierung dient. Der Heizwendel 7 liegt die Anode 9 gegenüber, die als Drehanode ausgebildet ist. Zum Betrieb der Heizwendel 7 wird über Leitungen 10 und 11 eine Heizspannung an die Heizwendel 7 angelegt. Die Hochspannung wird der Röntgenröhre über eine Leitung 12 und einen am anodenseitigen Ende der Röntgenröhre 2 liegenden Anschlußstutzen 13 zugeführt, die die aus der Heizwendel 7 austretenden Elektronen entsprechend der Linie 17 beschleunigt.In Fig. 1, 1 denotes the glass bulb of an X-ray tube 2. Inside the piston 1, a cathode arrangement 3 is provided at one end and an anode arrangement 4 at the opposite end. The cathode arrangement 3 has a cathode pot 6 on its housing 5. This contains a heating coil 7, which is shown only schematically in the figures. The heating coil 7 is located in a groove-like recess 8 of the cathode pot 6, which is used for focusing. The heating coil 7 is opposite the anode 9, which is designed as a rotating anode. To operate the heating coil 7, a heating voltage is applied to the heating coil 7 via lines 10 and 11. The high voltage is fed to the X-ray tube via a line 12 and a connecting piece 13 located at the anode-side end of the X-ray tube 2, which accelerates the electrons emerging from the heating coil 7 in accordance with line 17.

Aus den Fig. 2 und 3 geht hervor, daß der Kathodentopf 6 senkrecht zur Längsrichtung der Heizwendel 7 in mehrere, und zwar in drei voneinander isolierte Teile 14, 15, 16 aufgeteilt ist. Den Teilen 14, 15, 16 des Kathodentopfes 6 sind getrennte Steuerpotentiale zuführbar. Dadurch ist es möglich, die Abmessungen des Fokus sowohl in Längs- als auch in Querrichtung über diese Steuerpotentiale zu beeinflussen. Bei dem Ausführungsbeispiel wird der Teil 15 mit dem Steuerpotential Ug1 versorgt. An den Teilen 14 und 16 liegt das Steuerpotential Ug2.2 and 3 show that the cathode pot 6 is divided perpendicularly to the longitudinal direction of the heating coil 7 into several, namely into three parts 14, 15, 16 which are insulated from one another. The parts 14, 15, 16 of the cathode pot 6 can be supplied with separate control potentials. This makes it possible to influence the dimensions of the focus both in the longitudinal and in the transverse direction via these control potentials. In the exemplary embodiment, the part 15 is supplied with the control potential Ug1. The tax potential Ug2 lies on parts 14 and 16.

Bei dem Ausführungsbeispiel ist als ausreichend angesehen, wenn der Kathodentopf 6 senkrecht zur Längsrichtung der Heizwendel 7 in drei Teile 14, 15, 16 unterteilt wird, deren Dicke in dieser Längsrichtung etwa gleich groß ist.In the exemplary embodiment, it is considered sufficient if the cathode pot 6 is divided perpendicularly to the longitudinal direction of the heating coil 7 into three parts 14, 15, 16, the thickness of which is approximately the same in this longitudinal direction.

Claims (2)

1. A cathode arrangement for a X-ray tube comprising a cathode pot for electron focussing which has a groove-like recess for the heating coil, characterised in that the cathode pot (6) is divided, approximately at right angles to the longitudinal direction of the heating coil (7), into a plurality of mutually insulated parts (14, 15, 16) which can be supplied with separate control potentials (Ugl, Ug2).
2. A cathode arrangement as claimed in Claim 1, characterised in that the cathode pot (6) consists of three parts (14, 15, 16) of approximately equal thickness in the longitudinal direction of the heating coil (7).
EP81100096A 1980-01-14 1981-01-08 Cathodes arrangement for an x-ray tube Expired EP0032385B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81100096T ATE3797T1 (en) 1980-01-14 1981-01-08 CATHODE ARRANGEMENT FOR AN X-RAY TUBE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803001141 DE3001141A1 (en) 1980-01-14 1980-01-14 CATHODE ARRANGEMENT FOR AN X-RAY TUBE
DE3001141 1980-01-14

Publications (2)

Publication Number Publication Date
EP0032385A1 EP0032385A1 (en) 1981-07-22
EP0032385B1 true EP0032385B1 (en) 1983-06-15

Family

ID=6092021

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81100096A Expired EP0032385B1 (en) 1980-01-14 1981-01-08 Cathodes arrangement for an x-ray tube

Country Status (4)

Country Link
US (1) US4373144A (en)
EP (1) EP0032385B1 (en)
AT (1) ATE3797T1 (en)
DE (2) DE3001141A1 (en)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4689809A (en) * 1982-11-23 1987-08-25 Elscint, Inc. X-ray tube having an adjustable focal spot
IL70210A (en) * 1982-11-23 1987-10-20 Elscint Ltd X-ray tube with adjustable focal spot
FR2538948B3 (en) * 1982-12-30 1985-10-18 Thomson Csf SCANNING X-RAY TUBE
US4685118A (en) * 1983-11-10 1987-08-04 Picker International, Inc. X-ray tube electron beam switching and biasing method and apparatus
FR2572215A1 (en) * 1984-10-19 1986-04-25 Thomson Cgr Radiological device with focus positional control along a given control axis
US4764947A (en) * 1985-12-04 1988-08-16 The Machlett Laboratories, Incorporated Cathode focusing arrangement
NL8603264A (en) * 1986-12-23 1988-07-18 Philips Nv ROENTGEN TUBE WITH A RING-SHAPED FOCUS.
US5007074A (en) * 1989-07-25 1991-04-09 Picker International, Inc. X-ray tube anode focusing by low voltage bias
IL91119A0 (en) * 1989-07-26 1990-03-19 Elscint Ltd Arrangement for controlling focal spot position in x-ray tubes
FR2650703B1 (en) * 1989-08-07 1991-10-11 Gen Electric Cgr X-RAY TUBE CATHODE AND TUBE THUS OBTAINED
DE4100297A1 (en) * 1991-01-08 1992-07-09 Philips Patentverwaltung X-RAY TUBES
FR2675629B1 (en) * 1991-04-17 1997-05-16 Gen Electric Cgr CATHODE FOR X-RAY TUBE AND TUBE THUS OBTAINED.
FR2687504B1 (en) * 1992-02-13 1994-04-08 General Electric Cgr IMPROVEMENTS ON X-RAY TUBES.
DE19510048C2 (en) * 1995-03-20 1998-05-14 Siemens Ag X-ray tube
DE19914739C1 (en) * 1999-03-31 2000-08-03 Siemens Ag Cathode with directly heated emitter
US6438207B1 (en) 1999-09-14 2002-08-20 Varian Medical Systems, Inc. X-ray tube having improved focal spot control
US7257194B2 (en) * 2004-02-09 2007-08-14 Varian Medical Systems Technologies, Inc. Cathode head with focal spot control
DE102009009159A1 (en) * 2009-02-16 2010-10-14 Siemens Aktiengesellschaft Focus head for X-ray tube, has emitter surrounded by blocking electrodes that are applied with blocking potential independent of one another, so that areas of emitting surface are blocked with respect to electron emission
US9524845B2 (en) 2012-01-18 2016-12-20 Varian Medical Systems, Inc. X-ray tube cathode with magnetic electron beam steering
US8831178B2 (en) 2012-07-03 2014-09-09 General Electric Company Apparatus and method of manufacturing a thermally stable cathode in an X-ray tube

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2249365A1 (en) * 1972-10-09 1974-04-25 Siemens Ag ROENTINE PIPE

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US2068287A (en) * 1933-10-14 1937-01-19 Gabor Denes Electric lamp
US2110604A (en) * 1935-08-24 1938-03-08 Westinghouse Electric & Mfg Co Double focus X-ray tube
US2215426A (en) * 1939-04-07 1940-09-17 Machlett Lab Inc X-ray tube
US3646379A (en) * 1970-05-18 1972-02-29 Machlett Lab Inc X-ray tube having controllable focal spot size
US3649861A (en) * 1970-09-09 1972-03-14 Picker Corp Double focus x-ray tube
US4266133A (en) * 1979-11-08 1981-05-05 Siemens Corporation Multiple focus X-ray generator

Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
DE2249365A1 (en) * 1972-10-09 1974-04-25 Siemens Ag ROENTINE PIPE

Also Published As

Publication number Publication date
US4373144A (en) 1983-02-08
EP0032385A1 (en) 1981-07-22
DE3001141A1 (en) 1981-07-16
DE3160422D1 (en) 1983-07-21
ATE3797T1 (en) 1983-06-15

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