EP3732702A1 - Dispositif d'émission d'électrons - Google Patents

Dispositif d'émission d'électrons

Info

Publication number
EP3732702A1
EP3732702A1 EP19704225.2A EP19704225A EP3732702A1 EP 3732702 A1 EP3732702 A1 EP 3732702A1 EP 19704225 A EP19704225 A EP 19704225A EP 3732702 A1 EP3732702 A1 EP 3732702A1
Authority
EP
European Patent Office
Prior art keywords
electron
grid
emission
emitter
electron emission
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.)
Pending
Application number
EP19704225.2A
Other languages
German (de)
English (en)
Inventor
Josef Deuringer
Jörg FREUDENBERGER
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 Healthineers AG
Original Assignee
Siemens Healthcare GmbH
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 Healthcare GmbH filed Critical Siemens Healthcare GmbH
Publication of EP3732702A1 publication Critical patent/EP3732702A1/fr
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
    • H01J1/46—Control electrodes, e.g. grid; Auxiliary electrodes
    • 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
    • H01J35/045—Electrodes for controlling the current of the cathode ray, e.g. control grids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2235/00—X-ray tubes
    • H01J2235/06—Cathode assembly
    • H01J2235/062—Cold cathodes
    • 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
    • H01J35/064—Details of the emitter, e.g. material or structure
    • 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
    • H01J35/065—Field emission, photo emission or secondary emission cathodes
    • 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

Definitions

  • the invention relates to an electron emission V oroplasty.
  • a V or electron emission device which includes an electron emitter with an emitting surface and a shutter grid.
  • the barrier grid is spaced from the emission surface of the electron emitter and has a predeterminable number of individually controllable grid segments. All grid segments are each assigned a switch and a series resistor. The grids segments can each be switched on or off by the switches.
  • 5, 857, 883 discloses electron emission US a V orcardi with an electron emitter and a side facing the shutter grid emission surface.
  • the barrier grid is spaced from the emission surface of the electron emitter and has a plurality of individually switchable grid segments.
  • an electron emission orcardi V which is designed as a thermionic emission orcardi V is described, for example, 315 B2 in US 8,374.
  • the electron emission V oroplasty comprises at least one flat emitter having at least one emission area, the thermally emits electrons upon application of a heating voltage. Further comprising the known electron emission V orterrorism Wenig least one locking grille that is spaced apart from the emission surface of the Flachemit ters.
  • the barrier grid acts as a control electrode, since the emission of electrons from the material of the emission surface can be varied by applying a grid voltage. As a result, defined partial beams of the electron emission can be generated.
  • US Pat. No. 7,835,501 B2 and DE 10 2012 209 089 A1 describe the possibility of an increase in power due to the use of asymmetric focal spot shapes.
  • Field effect emission cathodes are e.g. in US Pat. No. 7,751,528 B2 (in particular FIG. 1 lb and FIG. 8) and in the publication "Multisource inverse-geometry CT. Part II. X-ray source design and prototype" (authors: V. Bogdan Neculaes et al.) in Medical Physics 43 (8), August 2016, pages 4617-4627, in particular special FIG 7) described.
  • an emitter material carbon nanotubes or Dis an cathode material, such as barium oxide
  • Dispenser cathodes are also referred to as post-delivery cathodes or as supply cathodes.
  • Object of the present invention is to provide an electron emission device for an X-ray tube, which allows a simple way to adjust the image quality at ge ringstsammlunger anode load.
  • the electron emission device comprising at least one electron emitter with at least one emission surface and at least one barrier grid, which is spaced from the Emis sion surface of the electron emitter and a predetermined number of individually controllable grid segments.
  • at least one individually specifiable grid voltage can be applied to each of the grid segments.
  • the predetermined grid voltage here lies between a lower limit value, which does not necessarily have to be zero, and an upper limit value, which may also be less than half of an admissible maximum value.
  • At least one individually specifiable grating voltage can be applied to each of the grating segments, for a predefinable number of individually controllable grating segments, specifically defined sub-beams of the electron beam (electron partial beams) can be generated.
  • the shutter grid is thus, in the electron emission V oroplasty according to claim 1, a reliable control electrode.
  • the segmented barrier grid is spaced from the emission surface of the electron emitter. Due to the individually controllable grating segments, different voltage patterns can be generated by which a multiplicity of different electron beams can be generated. In the context of the invention it is e.g. it is possible in each case alternately to allow electron emission by means of a single grid segment. However, it is also possible that several grids segments, which need not necessarily be arranged adjacent, simultaneously allow emission of electrons from the emission surface of the electron emitter. Thus, by targeted blocking of individual grid segments the
  • the individual grid segments are differently permeable to the emitted electrons due to the respective applied grid voltages.
  • a grid segment which is applied to a lower grid voltage, a correspondingly higher here electron emission occurs.
  • the barrier grid or. the lattice segments always have a positive potential with respect to the emission surface of the electron emitter.
  • the grating segments in the non-emitting regions are either at the potential of the emission surface of the electron emitter or at a potential which is more negative than the potential of the electron emitter. If one chooses the potentials accordingly, then the electron beam can be deflected or focused in the emission area. The distribution of the emitted electrons is thus almost arbitrary.
  • the electron emitter is used as a dispenser.
  • ser-cathode also referred to as “Spindtkathode”
  • ser-cathode also referred to as “Spindtkathode”
  • the term "dispenser cathode” is understood to mean a cathode in which the carrier material is coated with a dispenser cathode material which emits electrons when an electric field strength is applied.
  • Suitable dispenser cathode materials include, for example, barium oxide (BaO) and lanthanum hexaboride (LaB 6) .
  • the electron emitter is formed as a field effect emitter, which is also emitted when an electric field strength electrons (claim 3).
  • the field effect emitter example as CNT-based field emitter (CNT, carbon nanotubes, carbon nanotubes) or as a Si-based field emitter (Si, silicon) may be performed.
  • Nanocrystalline diamond is also suitable for the production of cold cathodes according to DE 197 27 606 A1.
  • the electron emission V or croqu the electron emitter as thermi shear emitter is formed which emits electrons upon application of a heating voltage (claim 4).
  • the emission surface of the electron emitter is structured. In the case of a flat emitter having a rectangular surface, this structuring can be realized, for example, by slits on the emission surface
  • a second barrier grid is angeord net spaced to the barrier grid, wherein the planes of the two barrier grid parallel to each other, and wherein the second barrier grid if just a predetermined number of individually controllable Git has tersegmenten and the grid segments of the blocking grid orthogonal to the grid segments of the second barrier grid (claim 5).
  • the emission V grant the electrons in two directions arbitrarily controlled who the.
  • the electron emission device according to the invention or. their advantageous embodiments are suitable for installation in a focus head (claim 6).
  • FIG. 5 shows a longitudinal section through an embodiment of a
  • Electron emission orcardi V, 6 shows a plan view of the electron emission device according to FIG. 5.
  • the electron emission device shown in principle in FIG. 1 comprises an electron emitter 2 with an emission surface 3 and with a blocking grid 5, which is spaced apart from the emission surface 3 of the electron emitter 2.
  • the invention is not limited to a single electron emitter 2 and not to a single emission surface 3.
  • both a plurality of electron emitter 2 and a plurality of emission surfaces 3 per electron emitter 2 can be provided.
  • multiple blocking grid 5 may be provided. Only for reasons of clarity was this restriction chosen in the schematic presentation.
  • a freely selectable grating voltage U Gi to U GN can be applied (see FIG. 6).
  • a different grating voltage U GN can also be applied. In this way, in the regions between the respective grid segments G 1 to G N and the emission surface 3, different electric fields are present, which leads to different emissions of electrons from the emission surface 3 of the electron emitter 1.
  • the emission distributions shown in FIGS. 2 to 4 are achievable for the electrons emerging from the emission surface 3.
  • the grid segments Gi to G s were always placed in a Cartesian coordinate system on the The abscissa and the electron emission E are plotted on the ordinate.
  • the grid voltages U Gi to U GN at the grid segments Gi to G N are selected such that two equally strong grid voltages U Gi and U GN are applied to the grid segments Gi and G N , as a result of which the electron emissions E are equally strong.
  • the grating segments G2 to G N -I are however blocked by the application of higher gate voltages U G 2 to U GN-i , so that no electrons emerge from the grating segments G2 to G N -I.
  • the grating voltages U Gi to U GN at the grating segments Gi to G N in the emission distribution illustrated in FIG. 3 are different.
  • the electron emissions E are freely selectable by applying a desired grid voltage U GN , whereby the MTF (modulation transfer function) can be influenced accordingly.
  • the MTF of the resulting on an anode distribution of the X-ray emission thus contains high-frequency components, whereby the limit resolution of the overall system can be positively influenced (coded spot).
  • the grating segments G2 and G4 are completely blocked, whereas an at least partial electron emission E is possible by the grating segments Gi, G3 and G s to G N.
  • the emission distribution according to FIG. 4 is an asymmetrical emission distribution of the electrons passing through the blocking grid 5.
  • the grating segments Gi to G 5 are differently permeable to the emitted electrons due to the grating voltages U Gi to U GN applied in each case.
  • the grid segment Gi has the lowest lattice voltage U Gi and thus the highest electron emission E.
  • the grid segment G5 lies on the grid segment G5, the highest lattice clamping voltage U G s, resulting in a correspondingly low electric nenemission E.
  • the electrons emitted by the electron emitter 2 generate electrons upon impinging on an in FIG. 4 not shown rotary anode an asymmetrical focal spot, which allows a higher electron beam power.
  • An embodiment for an electron emission device 1 is shown in longitudinal section in FIG. 5 and in plan view in FIG.
  • an emitter material 6 is applied, which emits electrons in an emission surface 3 (electron emission E).
  • the substrate 4 is, for example, a base body made of a technical ceramic.
  • the emitter material 6 is, for example, carbon nanotubes (CNT) or a dispenser cathode material, such as, for example, barium oxide (BaO) or lanthanum hexoboride (LaB 6 ).
  • the grid segments G 1 to G N are in each case individually controlled with the corresponding grid voltages U Gi to U GN .
  • the grating segments G 3 to G NI are not shown.
  • the blocking grid 5 can be made, for example, from a tungsten sheet, from which the grid segments Gi to G N , which form the grid structure, have been cut out by laser cutting.
  • a second barrier grid (not shown) parallel and orthogonal as well as at a distance from the barrier grid 5.
  • the second barrier also has a predetermined number of individually controllable grid segments.
  • the emission distribution E of the electrons can be arbitrarily controlled in two spatial directions.
  • the segmented barrier grid 5 from the embodiment according to FIGS. 5 and 6 is also suitable for optimizing the electron emission device known from US Pat. No. 8,374,315 B2.
  • the solution according to the invention makes it possible to improve image quality in a simple manner while simultaneously reducing the anode load by adapting the focal spot geometry (shape and size) to the specific application ,

Landscapes

  • X-Ray Techniques (AREA)
  • Cold Cathode And The Manufacture (AREA)

Abstract

L'invention concerne un dispositif d'émission d'électrons comprenant au moins un émetteur d'électrons (2) pourvu d'au moins une surface d'émission (3) et au moins une grille de blocage (5) qui est espacée de la surface d'émission (3) de l'émetteur d'électrons (2) et un nombre prédéterminable de segments de grille commandables individuellement (G1 – G7, GN). Selon l'invention, au moins une tension de grille prédéterminable individuellement peut être appliquée à chacun des segments de grille (G1 – G7, GN). Un tel dispositif d'émission d'électrons permet d'adapter de manière simple la qualité d'image avec une charge d'anode la plus faible possible.
EP19704225.2A 2018-02-27 2019-01-25 Dispositif d'émission d'électrons Pending EP3732702A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP18158898.9A EP3531437A1 (fr) 2018-02-27 2018-02-27 Dispositif d'émission d'électrons
PCT/EP2019/051860 WO2019166161A1 (fr) 2018-02-27 2019-01-25 Dispositif d'émission d'électrons

Publications (1)

Publication Number Publication Date
EP3732702A1 true EP3732702A1 (fr) 2020-11-04

Family

ID=61521344

Family Applications (2)

Application Number Title Priority Date Filing Date
EP18158898.9A Withdrawn EP3531437A1 (fr) 2018-02-27 2018-02-27 Dispositif d'émission d'électrons
EP19704225.2A Pending EP3732702A1 (fr) 2018-02-27 2019-01-25 Dispositif d'émission d'électrons

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP18158898.9A Withdrawn EP3531437A1 (fr) 2018-02-27 2018-02-27 Dispositif d'émission d'électrons

Country Status (4)

Country Link
US (1) US11373835B2 (fr)
EP (2) EP3531437A1 (fr)
DE (1) DE202019006062U1 (fr)
WO (1) WO2019166161A1 (fr)

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4100297A1 (de) * 1991-01-08 1992-07-09 Philips Patentverwaltung Roentgenroehre
US5857883A (en) * 1997-05-09 1999-01-12 International Business Machines Corporation Method of forming perforated metal/ferrite laminated magnet
DE19727606A1 (de) 1997-06-28 1999-01-07 Philips Patentverwaltung Elektronenemitter mit nanokristallinem Diamant
US6249569B1 (en) * 1998-12-22 2001-06-19 General Electric Company X-ray tube having increased cooling capabilities
US20040240616A1 (en) * 2003-05-30 2004-12-02 Applied Nanotechnologies, Inc. Devices and methods for producing multiple X-ray beams from multiple locations
ATE473685T1 (de) 2005-12-27 2010-07-15 Siemens Ag Fokus-detektor-anordnung zur erzeugung von phasenkontrast-röntgenaufnahmen und verfahren hierzu
US8189893B2 (en) * 2006-05-19 2012-05-29 The University Of North Carolina At Chapel Hill Methods, systems, and computer program products for binary multiplexing x-ray radiography
EP2082412B1 (fr) 2006-10-13 2011-05-18 Philips Intellectual Property & Standards GmbH Tube à rayons x, système à rayons x et procédé de production de rayons x
WO2009012453A1 (fr) 2007-07-19 2009-01-22 The University Of North Carolina At Chapel Hill Systèmes de tomosynthèse numérique du sein aux rayons x stationnaires et procédés apparentés
DE102008046288B4 (de) 2008-09-08 2010-12-09 Siemens Aktiengesellschaft Elektronenstrahlsteuerung eines Röntgenstrahlers mit zwei oder mehr Elektronenstrahlen
DE102009007217B4 (de) 2009-02-03 2012-05-24 Siemens Aktiengesellschaft Röntgenröhre
EP2443643B1 (fr) * 2009-06-17 2016-12-14 Philips Intellectual Property & Standards GmbH Tube à rayons x pour générer deux points focaux et dispositif médical le comprenant
DE102010043540A1 (de) * 2010-11-08 2012-03-15 Siemens Aktiengesellschaft Röntgenröhre
DE102012209089A1 (de) 2012-05-30 2013-12-05 Siemens Aktiengesellschaft Röntgenröhre mit einer Drehanode
DE102017105546B4 (de) * 2017-03-15 2018-10-18 Yxlon International Gmbh Steckdose zur Aufnahme eines Steckers eines Hochspannungskabels für eine Mikrofokus-Röntgenröhre, Steckverbindung für ein Hochspannungskabel

Also Published As

Publication number Publication date
US20210082653A1 (en) 2021-03-18
US11373835B2 (en) 2022-06-28
WO2019166161A1 (fr) 2019-09-06
DE202019006062U1 (de) 2024-06-10
EP3531437A1 (fr) 2019-08-28

Similar Documents

Publication Publication Date Title
DE102009003673B4 (de) Elektronenquelle auf der Basis von Feldemittern mit minimierten Strahl-Emittanzwachstum
DE112009001604B4 (de) Thermionenemitter zur Steuerung des Elektronenstrahlprofils in zwei Dimensionen
DE102008046721B4 (de) Kathode mit einem Parallel-Flachemitter
DE2518688C2 (de) Röntgenröhre
DE10334606A1 (de) Kathode für Hochemissions-Röntgenröhre
DE19820243A1 (de) Drehkolbenstrahler mit Fokusumschaltung
DE102011076912A1 (de) Röntgengerät umfassend eine Multi-Fokus-Röntgenröhre
DE102005049601A1 (de) Vorrichtung zur Erzeugung von Röntgenstrahlung mit einer kalten Elektronenquelle
DE10228545A1 (de) Verfahren und System zur Erzeugung eines Elektronenstrahls in Röntgenstrahl-Erzeugungsvorrichtungen
DE102008011841B4 (de) Kathode
WO2019057338A1 (fr) Tube mbfex
EP2092542B1 (fr) Dispositif d'émission de champ
DE2748322A1 (de) Kathodensystem
WO2019166161A1 (fr) Dispositif d'émission d'électrons
WO2019149482A1 (fr) Dispositif d'émission
DE102015215690A1 (de) Emitteranordnung
DE102016215375B4 (de) Thermionische Emissionsvorrichtung
DE3538175A1 (de) Halbleiteranordnung mit erhoehter stabilitaet
DE69936929T2 (de) Elektronenhohlstrahl-schaltröhre mit hoher spannungsfestigkeit und stromregelung
DE4002049C2 (de) Elektronenemissionsquelle und Einrichtung zum Bestrahlen von Medien mit einer solchen Elektronenemissionsquelle
DE3342127A1 (de) Roentgenroehre mit einstellbarem brennfleck
DE102009009159A1 (de) Fokuskopf einer Röntgenröhre und zugehöriges Betriebsverfahren
DE69620799T2 (de) Kathodenanordnung fur ein elektronenstrahlgerät mit einem linienbrennpunkt
DE102024201255A1 (de) Feldeffekt-Elektronenemitter mit gruppierten Teilemissionsflächen
DE69813938T2 (de) Schaltröhre

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20200727

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: SIEMENS HEALTHINEERS AG

17Q First examination report despatched

Effective date: 20240208