EP0168883A1 - Detektorröhre für Röntgenstrahlung - Google Patents

Detektorröhre für Röntgenstrahlung Download PDF

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Publication number
EP0168883A1
EP0168883A1 EP85201095A EP85201095A EP0168883A1 EP 0168883 A1 EP0168883 A1 EP 0168883A1 EP 85201095 A EP85201095 A EP 85201095A EP 85201095 A EP85201095 A EP 85201095A EP 0168883 A1 EP0168883 A1 EP 0168883A1
Authority
EP
European Patent Office
Prior art keywords
detector tube
anode
tube according
housing
strip
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.)
Withdrawn
Application number
EP85201095A
Other languages
English (en)
French (fr)
Inventor
Hendrik Mulder
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.)
Optische Industrie de Oude Delft NV
Original Assignee
Optische Industrie de Oude Delft NV
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 Optische Industrie de Oude Delft NV filed Critical Optische Industrie de Oude Delft NV
Publication of EP0168883A1 publication Critical patent/EP0168883A1/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H01J31/506—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output tubes using secondary emission effect
    • H01J31/507—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output tubes using secondary emission effect using a large number of channels, e.g. microchannel plates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/49—Pick-up adapted for an input of electromagnetic radiation other than visible light and having an electric output, e.g. for an input of X-rays, for an input of infrared radiation

Definitions

  • the invention relates to an X-ray detector tube comprising an elongate housing having an elongate cathode and an elongate anode mounted therein to extend essentially parallel with each other, in which an electrical potential is applied across the anode and the cathode during operation and the tube has been evacuated.
  • a drawback inherent in the prior detector tube is that the intensification of the electrons released in the cathode in response to incident X-radiation for emission to the anode is relatively poor. As a result, for example, no photodiodes can be used at the anode for detecting the image produced on the anode as in such diodes the noise and the dark current constitute too large a part of the final signal current. Other types of electronic processing of the signal received at the anode are likewise problematic on account of the extremely poor signal strength.
  • the detector tube is provided with a so-called channel plate mounted between the cathode and the anode to extend essentially parallel therewith.
  • a major advantage of the use of a channel plate in an X-ray detector tube of the type described in Dutch patent application 79,00878 is that, for achieving a good result, the channel-shaped apertures in the plate may be of larger diameter than those in the known channel plate, while also the channel-shaped apertures may be spaced a larger distance apart from each other. This permits a cheaper manufacture of the channel plate.
  • the resultant intensification may be as much as 1000 times greater than that in the prior tube.
  • a conventional anode can be used, i.e. a phosphor layer deposited on an anode support, which anode is operative as a viewing screen.
  • the image formed on this viewing screen can be further processed by means of, for example, photodiodes as well as conventional optical means.
  • the anode is preferably arranged for permitting electronic processing of the electrons incident thereon, which electrons are representative of the intensified X-ray image.
  • Fig. 1 shows in cross-sectional view an X-ray detector tube comprising an elongate housing 1 and a cathode support 2 on which a layer of X-ray detection material, such as CsI, and a photocathode are provided in known per se manner, which layer and photocathode are not shown.
  • a channel plate 3 extends substantially parallel with cathode support 2.
  • This plate is made of a semiconductive glass and includes a large number of small channels extending essentially normal to the surface of the plate.
  • the channels may have an aperture of 100 micrometer and may be spaced a distance of likewise 100 micrometer apart from each other.
  • the plate has a thickness of, for example, 40 times the diameter of the channels.
  • An anode support 4 extends essentially parallel with channel plate 3 at some distance therefrom.
  • the electrical potential differences may be, for example:
  • the tube shown in Fig. 1 the envelope of which is made of glass, preferably has its inner surface provided with a conductive coating of, for example, copper evaporated thereon. Otherwise, free electrons in the detector tube may strike the glass tube wall and cause this wall to become locally charged. Such a charge can so disturb the field in the tube that the image of the cathode as formed on the anode, which image is normally undistorted in principle, becomes slightly distorted indeed. Moreover, such a charge can cause flashover within the tube and the resultantly occurring light effects disturb the image and reduce the contrast.
  • the conductive coating on the inner surface of the tube captures the free electrons and takes care of their removal.
  • the conductive coating is preferably of copper, which is a poor reflector to blue light.
  • a known per se phosphor layer (not shown) is provided on anode support 4.
  • the phosphor elements in this layer are caused to fluoresce by the electrons emitted by the photocathode in response to incident X-radiation and intensified by channel plate 3, so that an X-ray image is produced which can be further processed by conventional techniques, for example by using optical means, or by scanning by means of photodiodes.
  • the anode support 4 is made of an insulating material, such as glass or ceramic material, on which a large number of mutually insulated, parallel, strip-like conductors 5 has been deposited by, for example, evaporation in the manner shown in Fig. 2a and Fig. 2b.
  • Each strip conductor 5 is operative as an independent anode on which the electrons multiplied in number by the channel plate are collected.
  • the charge on the respective strip conductors 5 is removed by means of a large number of leads extending through the tube wall via associated vacuum-tight bushings 6, which leads are connected to strip conductors 5 at the bottom end of anode support 4 in the embodiment of Fig. 2a and at alternately the bottom end and the top end of anode support 4 in the embodiment of Fig. 2b.
  • Fig. 3 shows a variant of the detector tube of Fig. 2, which includes an anode support with strip conductors arranged in the manner of Fig. 2a.
  • Housing 7 of the detector tube has a tubular shape and has its forward end covered by a foil 8 that is transmissive to X-radiation, which foil permits a vacuum to be maintained in the tube.
  • Vacuum-tight glass-soldered joint 9 seals anode support 4 to tubular housing 7.
  • Fig. 4 shows a variant of the embodiment of Fig. 3, in which the detector tube includes an anode support with strip conductors arranged in the manner of Fig. 2b.
  • the housing of the detector tube has a tubular shape and consists of a first housing section 7' and a second housing section 7" with anode support 4 mounted between these housing sections. Glass-soldered joints 9 ensure a vacuum-tight seal between the housing and the anode support.
  • strip conductors 5 protrude beyond the bottom end of the tube and in the embodiment of Fig. 4 strip conductors 5 alternately protrude beyond the top end and the bottom end of the tube, so that each of strip conductors 5 is contactable outside the housing.
  • the embodiment of the anode support according to Fig. 2b may also be applied to the detector tubes shown in Fig. 3 and the anode support according to Fig. 2a to the embodiment of the detector tube shown in Fig. 4.
  • Strip conductors 5 on the anode support are maintained at a, for example, 100 volts higher voltage than the voltage at the exit end of the channel plate.
  • the charge on anode strips 5 can be sequentially applied to an amplifier through an electronic switch mounted on an electronic print located outside the detector tube, and can then be further processed.
  • the insulating support should either be made of a material of very low electrical conductivity or be provided with a layer of low electrical conductivity on its face supporting the strip conductors.
  • the strip conductors may have a length of, for example, 10 mm and may be spaced a distance of, for example, 0.5 mm apart on the anode support.
  • the strip conductors collect all charge originating from a strip of, for example, CsI of the same height as that of the conductors, which strip is provided on the cathode support.
  • the anode consists of an insulating support 4 of, for example, glass or ceramic material, through which support 4 conductive pins 10 extend. Pins 10 allow removal of the charge to outside the detector tube.
  • support 4 is at the same time operative as a vacuum seal for the tubular housing 7.
  • Pins 10 may form a one-dimensional as well as a two-dimensional pattern, the latter being shown in Fig. 5. Inside housing 7 the pins are connected to electrically conductive strips in the case of a one-dimensional pattern or to electrically conductive islands, such as 10' in Fig. 5, in the case of a two-dimensional pattern.
  • Such strips or islands are operative as collectors for the flow of electrons multiplied by channel plate 3.
  • the pins are connected to one or more amplifiers through electrical switches. This connection can be established, for example, via a plate 11 provided with contact points 12 arranged in a pattern corresponding to that of pins 10. Also in the embodiment of Fig. 5 the charge striking the anode support at regions between the strips or islands 10' is to be removed.
  • Fig. 6 shows a variant of an anode by means of which a two-dimensional image can be formed.
  • strip conductors 13 have been evaporated on anode support 4 in the manner of Fig. 2a.
  • each strip conductor 13 consists of a number of conductors deposited in superposition but separated by intermediate insulating layers 16, with each conductor being shorter than the ones thereunder to define islands 13' receiving the electrons from a corresponding region of the cathode.
  • the charge received on islands 13' can be removed at the bottom end of strip conductors 13 via contact spots 13".
  • Fig. 6a shows a cross-sectional view along lines VIa-VIa in Fig. 6, in which the thickness of the evaporated strips has been highly exaggerated for the sake of clarity.
  • the anode comprises a phosphor layer 14 deposited on an insulating anode support 4 which, similar to the embodiment of Fig. 2, is provided with mutually parallel strip conductors 5. These strip conductors, however, are transmissive to the light generated in the phosphor.
  • a layer 15 of aluminium foil is provided on the phosphor screen, which layer 15 should be electrically insulated relative to the strip conductors. Electrons penetrating through the aluminium foil into the phosphor layer loose their kinetic energy as they produce excited centers, which emit light after recombination. Electrons having sufficient energy to pass through the phosphor layer reach the underlying conductive strips 5 and can be processed in the manner described above with reference to Fig. 2. A small potential difference between aluminium foil 15 and conductive strips 5 is desired but not always necessary.
  • An X-ray detector tube with channel plate and with an anode as shown in Fig. 7 can produce both an optical two-dimensional image and, concurrently therewith, an electrical one-dimensional image.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Measurement Of Radiation (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Electron Tubes For Measurement (AREA)
EP85201095A 1984-07-05 1985-07-04 Detektorröhre für Röntgenstrahlung Withdrawn EP0168883A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL8402140 1984-07-05
NL8402140A NL8402140A (nl) 1984-07-05 1984-07-05 Detectorbuis voor roentgenstraling.

Publications (1)

Publication Number Publication Date
EP0168883A1 true EP0168883A1 (de) 1986-01-22

Family

ID=19844178

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85201095A Withdrawn EP0168883A1 (de) 1984-07-05 1985-07-04 Detektorröhre für Röntgenstrahlung

Country Status (3)

Country Link
EP (1) EP0168883A1 (de)
JP (1) JPS6132343A (de)
NL (1) NL8402140A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990009681A1 (en) * 1989-02-08 1990-08-23 B.V. Optische Industrie 'de Oude Delft' Particle detector
US5404387A (en) * 1992-11-13 1995-04-04 Hammond; David J. Body scanning system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896088A (en) * 1954-11-26 1959-07-21 Westinghouse Electric Corp Regenerating scintillation counter
FR1411133A (fr) * 1963-08-01 1965-09-17 Tektronix Inc Cible d'emmagasinage pour tube à rayon cathodique et son procédé photographique de fabrication
DE1764095A1 (de) * 1968-04-02 1971-04-22 Acker Norbert Karl Bildverstaerker- oder Bildwandlerroehre
US4186302A (en) * 1976-11-12 1980-01-29 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US4341955A (en) * 1979-02-02 1982-07-27 N.V. Optische Industrie "De Oude Delft" Image intensifier of the proximity-focus type

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2896088A (en) * 1954-11-26 1959-07-21 Westinghouse Electric Corp Regenerating scintillation counter
FR1411133A (fr) * 1963-08-01 1965-09-17 Tektronix Inc Cible d'emmagasinage pour tube à rayon cathodique et son procédé photographique de fabrication
DE1764095A1 (de) * 1968-04-02 1971-04-22 Acker Norbert Karl Bildverstaerker- oder Bildwandlerroehre
US4186302A (en) * 1976-11-12 1980-01-29 Diagnostic Information, Inc. Panel type X-ray image intensifier tube and radiographic camera system
US4341955A (en) * 1979-02-02 1982-07-27 N.V. Optische Industrie "De Oude Delft" Image intensifier of the proximity-focus type

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
L.MARTON et al.: "ADVANCES IN ELECTRONICS AND ELECTRON PHYSICS, vol. 33a, J.D.McGEE et al.: Photo Electronic Image Devices, Proceedings of the Fifth Symposium held at Imperial College London, 13th-17th September 1971, 1972, Academic Press, New York, US; I.C.P.MILLAR et al.: "Channel electron multiplier plates in X-ray image intensification" *
PATENTS ABSTRACTS OF JAPAN, vol. 7, no. 88 (E-170)[1233], 12th April 1983; & JP - A - 58 14 457 (NIPPON DENKI K.K.) 27-01-1983 *
SCIENTIFIC AMERICAN, vol. 245, no. 5, November 1981, pages 46-55, New York, US; M.LAMPTON: "The microchannel image intensifier" *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1990009681A1 (en) * 1989-02-08 1990-08-23 B.V. Optische Industrie 'de Oude Delft' Particle detector
US5404387A (en) * 1992-11-13 1995-04-04 Hammond; David J. Body scanning system

Also Published As

Publication number Publication date
JPS6132343A (ja) 1986-02-15
NL8402140A (nl) 1986-02-03

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

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Effective date: 19860605

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Effective date: 19880202

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Inventor name: MULDER, HENDRIK