US3904532A - Inlet screen for intensifying x-ray images - Google Patents

Inlet screen for intensifying x-ray images Download PDF

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Publication number
US3904532A
US3904532A US440707A US44070774A US3904532A US 3904532 A US3904532 A US 3904532A US 440707 A US440707 A US 440707A US 44070774 A US44070774 A US 44070774A US 3904532 A US3904532 A US 3904532A
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US
United States
Prior art keywords
layer
carrier
screen
accordance
photocathode
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
US440707A
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English (en)
Inventor
Hermann Christgau
Wolfgang Schubert
Aribert Stachowiak
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
Siemens Corp
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Siemens Corp
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 Corp filed Critical Siemens Corp
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Publication of US3904532A publication Critical patent/US3904532A/en
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Expired - Lifetime 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/38—Photoelectric screens; Charge-storage screens not using charge storage, e.g. photo-emissive screen, extended cathode
    • H01J29/385—Photocathodes comprising a layer which modified the wave length of impinging radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/12—Manufacture of electrodes or electrode systems of photo-emissive cathodes; of secondary-emission electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/50005—Imaging and conversion tubes characterised by form of illumination
    • H01J2231/5001—Photons
    • H01J2231/50031—High energy photons
    • H01J2231/50036—X-rays

Definitions

  • An inlet screen for intensifying X-ray images has a layer applied upon a carrier and caused to light by X- rays, as well as a photocathode combined with the Layer.
  • the invention is particularly characterized by the provision of a layer between the luminous layer and the carrier and absorbing the light of the luminous layer.
  • This invention relates to an inlet screen for intensifying X-ray images having a layer applied upon a carrier and excited to luminescence by X-rays and a photocathode combined therewith. Electrons are released in such layers the quantity of which depends upon the intensity of illumination and thus upon the distribution of brightness in a picture. These electrons are usually represented in an image amplifier electronic-optically upon a second luminous layer sensitive to electrons, which is then inspected or photographed. It can also be an inlet screen for television photography or an intermediate screen for the connection of a brightness amplifier. Instead of the second luminous screen when further amplifying steps are used. it is possible to provide screens in various arrangements which are excitable for sending secondary electrons.
  • the image quality of one of the above amplifying de vices which is expressed in the modulation transmission function, results from the image transmission properties of the individual stages.
  • image amplitier the picture is produced in stages, namely, X-rays are changed into electrons, the electrons are represented in an outlet screen and in the outlet screen the electrons are changed into a visible picture, so that there is a total of three stages. So far attempts have been made in each stage to do everything possible to provide the best possible pictures.
  • the inlet screen has been given the shape of a calotte with a non-uniform radius. This greatly improves the electronic optic being imaged.
  • the surface of this calotte coated with a luminous layer has been roughened to keep back reflections. Measures have also been carried out in the construction of other parts of the image amplifier to improve the imaging.
  • An object of the present invention is to provide further means for improving image transmitting properties.
  • the present invention is based substantially on the consideration that the surface of the carrier upon which the luminescent layer is applied is struck by about one half of theluminescent light, while the other half is substantially absorbed at the edge surface of the luminous layer toward the photocathode layer.
  • the carrier surface is smooth, the striking light rays are reflected. This means that light rays striking under greater angles mostly between the carrier surface and the edge layer are reflected between the luminous layer and the photocathode. This helps toward a general pic ture brightness, but not to an improvement of transmitted information. On the contrary, this is diminished since the brightness makes the background brighter and is not combined any more with a direct representation of the details of the picture.
  • an improvement is achieved by providing the inlet screen of the image amplifier between the luminous layer and the carrier with a layer absorbing the light of the luminous layer. This provides that the luminescent light, striking close to the carrier, is not reflected any more at least to a large extent and thus can not increase the brightness of the background. This improves the picture.
  • the part of the light striking the carrier surface consists of the sum of the spectral intensity of the luminescence of the luminous substance and the spectrally dependent absorption at the intermediate layer.
  • a luminous substance consisting of cesium iodide when activated with sodium
  • can be used for example, berillium, titanium, nickel, carbon or zirconium, since they have corresponding absorption.
  • carbon these substances react, however, with an X-ray luminous pigment, such as cesium iodide.
  • gold was found to be a useable substance for intermediate layer.
  • the emission maximum of the luminous substance then is safely in the absorption range of the intermediate layer.
  • the extent of absorption can be adjusted by the thickness of the coating of the material for the intermediate layers.
  • useable substqnces can be mentioned chromium,'carbon, titanium monox ide.
  • the selection of material from which the intermediate layeris made depends from the used carrier material and the material of the luminous substance.
  • luminous substances can be used those the spectral emission of which, when engaged by X-rays, is adapted to the spectral sensitivity of the actual photocathode layer.
  • cesium iodide can be used, among others, zinc sulfide and Zinc cadmium sulfide which are activated with silver.
  • intermediate layers were used which were applied'between the luminous layer and the photocathode layer and consisted. for example, of aluminum oxide, magnesium oxide of silicic acid, so as to separate the two substances and prevent them from reacting with each other.
  • carrier all substances can be used which have sufficient mechanical firmness to be stable in vacuum, such as glass, titanium,
  • the carrier which is occasionally called substratum can be roughened upon the side which is to be coated with the luminous substance whereby the roughness can have the depth of about 3 to 40 m.
  • This roughness can be carried out by all known methods, for example, by the application of particles transmitted by a gas or liquid ray, by rough stamping or by corroding with the use of hydrochloric acid and hydrofluoric acid, or also by solutions of alkali-ammonium, iron, and chromium salts, or plasma spraying of colored metal oxides for producing a rough surface which at the same time has the desired absorption due to its coloring.
  • the photocathode layer can be used a known combination of antimony and alcali metals, such as cesium, sodium, potassium.
  • FIG. 1 is a diagrammatic section through an image amplifier having an inlet screen which is constructed in accordance with the present invention.
  • FIG. 2 is an enlarged section through the inlet screen.
  • FIG. 3 is a diagrammatic section through a steaming. device for applying the intermediate layer and possibly also the luminouslayer.
  • FIG. 1 shows the vacuum-tight casing l of the image amplifier.
  • Theinlet screen 2 consisting of a combination of layers, is located behind the inlet window 3. Behind the window 3 and the screen 2 are located ring electrodes .4, S and the anode 6 which is also ringshaped.
  • the end of the device is constituted by a luminous layer 7 which at theside directed. toward the inlet screen is coated by a thin aluminum layer 8.
  • the opposite side of the screen 7 is limited by the end window 9 of the image amplifier.
  • The-inlet screen 2 is held at the inner wall of the casing l by bars extending from the wall to the carrier 12. Two bars 10 and Here shown in. FIG, 1.
  • the carrier Two bars 10 and Here shown in. FIG, 1.
  • the carrier The carrier.
  • the carrier 12 of the inlet screen 2 consists of a calotte of aluminum sheet curved according to requirements of electronic optics. Prior to the coating with the luminous layer it is cleaned and its fat removed in a cleaning solution in a .known manner. Afterthe pickling it is thoroughly rinsed with water and the inwardly curved side of the carrier 12 is coated with a caustic solution and further treated in a known manner until the roughening depth of 3' ,to 40 ,u.m, in this caseZOum, hasbeen reached. To complete the roughening it is rinsed with water and then the carrier 12 is dried. I w
  • intermediate layer l3 consisting of gold and takes place under the bell jar 16 in high vacuum, produced by the pump 17.
  • the carrier 12 is placed upon supports, two of which, designated as l8 and 19, are shown in FIG, 3.
  • the actual steaming with gold takes place by a steamer 21 driven by the current source and having a steaming shuttle 22 containing the substance 23 to be steamed, namely, gold. It is steamed upon the carrier 12, as shown by broken lines 24.
  • a sufficiently absorbing layer is produced by steaming 500 mg gold.
  • the distance of the carrier l2 from the substance 23 which is being steamed on amounts to 230 mm and is maintained by supports 18 and 19 (FIG. 3).
  • the intermediate layer 13 the luminous layer 14 is steamed on.
  • the screen is built into the container 1 prior to theapplication of the photocathode layer 15 which consists, as is known, of antimony and cesium.
  • the amount of gold applied as the intermediate layer is so measured that a sufficiently thick coating of the rough substrata surface is produced. In the present case this is an amount which is condensed when in a presteaming'sub-strata distance of at least about mm about 400 mg are evaporated. In the technology used gasing must take place prior to the introduction into the molten vacuum casing l of the image amplifier. As shown in FIG. 2 a sufficient covering is already provided when the surface of the carrier .12 to be covered by a luminous layer 14 is provided by roughening with a plurality of closely located bag-like, openings 25 the bases of which are covered with the absorbing layer 13.
  • This division of the layer 14 upon the bases 26 of the openings 25 has an advantage produced by intermediate walls 27; which cause the guiding of the luminescent light. up to the height of these intermediate walls 27 only within the hollow space, whereby this light can be thrown back and is spread also in theluminous layer 14 over the intermediate walls only as a cone of a small angle.
  • the advantage consists in that the light emitted by x-ray excitation has a preferred orientation to the photocathode 15.
  • An inlet screen for intensifying X-ray images comprising a carrier, a layer carried by said carrier and adapted to luminesce under the action of X-rays, a photocathode connected with said layer, and another layer located between said carrier and the first-mentioned layer and absorbing the light of the first-mentioned layer, said carrier being roughened prior to the application of the second-mentioned layer, the depth of the roughening ranging between 3 and 40pm, said rough-' ening forming holes with bases, said bases being covered with the secondmentioned layer.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US440707A 1973-02-13 1974-02-08 Inlet screen for intensifying x-ray images Expired - Lifetime US3904532A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2307026A DE2307026C2 (de) 1973-02-13 1973-02-13 Röntgenbildverstärker-Eingangsschirm

Publications (1)

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US3904532A true US3904532A (en) 1975-09-09

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US440707A Expired - Lifetime US3904532A (en) 1973-02-13 1974-02-08 Inlet screen for intensifying x-ray images

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US (1) US3904532A (enrdf_load_stackoverflow)
DE (1) DE2307026C2 (enrdf_load_stackoverflow)
FR (1) FR2217799B1 (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4733089A (en) * 1982-04-20 1988-03-22 Fuji Photo Film Co., Ltd. Radiographic intensifying screen
US7141804B1 (en) * 2004-02-02 2006-11-28 Landauer, Inc. Detection of neutrons and heavy charged particles

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4266247A (en) * 1977-09-19 1981-05-05 General Engineering & Applied Research Proximity focused streak tube and streak camera using the same
FR2623659B1 (fr) * 1987-11-24 1990-03-09 Labo Electronique Physique Tube intensificateur d'images a rayons x
WO1998012731A1 (fr) * 1996-09-18 1998-03-26 Kabushiki Kaisha Toshiba Tube a image radiologique et son procede de fabrication

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783297A (en) * 1972-05-17 1974-01-01 Gen Electric X-ray image intensifier input phosphor screen and method of manufacture thereof

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2031123A1 (en) * 1970-06-24 1971-12-30 Siemens Ag Multi layer photo cathode - with buffer layer between carrier and phosphor
CA939428A (en) * 1970-09-30 1974-01-01 Howard D. Doolittle Image intensifier with improved input screen

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783297A (en) * 1972-05-17 1974-01-01 Gen Electric X-ray image intensifier input phosphor screen and method of manufacture thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4733089A (en) * 1982-04-20 1988-03-22 Fuji Photo Film Co., Ltd. Radiographic intensifying screen
US7141804B1 (en) * 2004-02-02 2006-11-28 Landauer, Inc. Detection of neutrons and heavy charged particles

Also Published As

Publication number Publication date
FR2217799B1 (enrdf_load_stackoverflow) 1978-09-08
FR2217799A1 (enrdf_load_stackoverflow) 1974-09-06
DE2307026C2 (de) 1983-01-20
DE2307026A1 (de) 1974-08-22

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