US3271608A - X-ray vidicon target assembly - Google Patents

X-ray vidicon target assembly Download PDF

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Publication number
US3271608A
US3271608A US191099A US19109962A US3271608A US 3271608 A US3271608 A US 3271608A US 191099 A US191099 A US 191099A US 19109962 A US19109962 A US 19109962A US 3271608 A US3271608 A US 3271608A
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US
United States
Prior art keywords
beryllium
ring
ray
layer
disc
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
US191099A
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English (en)
Inventor
Rome Martin
Harold O W Jordan
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.)
Machlett Laboratories Inc
Original Assignee
Machlett Laboratories Inc
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
Priority to NL292137D priority Critical patent/NL292137A/xx
Application filed by Machlett Laboratories Inc filed Critical Machlett Laboratories Inc
Priority to US191099A priority patent/US3271608A/en
Priority to US191085A priority patent/US3287581A/en
Priority to GB15818/63A priority patent/GB978878A/en
Priority to FR932829A priority patent/FR1355262A/fr
Priority to DE19631464377 priority patent/DE1464377A1/de
Application granted granted Critical
Publication of US3271608A publication Critical patent/US3271608A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • 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
    • H01J29/026—Mounting or supporting arrangements for charge storage screens not deposited on the frontplate
    • 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
    • H01J29/39—Charge-storage screens
    • H01J29/45—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen
    • H01J29/458—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen pyroelectrical targets; targets for infrared or ultraviolet or X-ray radiations
    • 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
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/48—Tubes with amplification of output effected by electron multiplier arrangements within the vacuum space
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
    • H01J5/02—Vessels; Containers; Shields associated therewith; Vacuum locks
    • H01J5/18—Windows permeable to X-rays, gamma-rays, or particles

Definitions

  • This invention relates to an X-ray vidicon and, more particularly, to a novel X-ray vidicon window assembly.
  • beryllium surfaces cannot be conveniently prepared with the high degree of uniformity and polishing required for high resolution pick-up tubes.
  • Both the microcrystalline structure and the protective oxide layer are detrimental influences on the selenium photoconductor substrate used with the beryllium window. That is, if the selenium photoconduotor is vaporized directly onto the beryllium metal, there occurs a detrimental recrystallization of the selenium from the amorphous to a lower resistivity crystalline form due, at least in part, to the beryllium.
  • Another object of our invention is to provide a means for preventing a reaction or change in crystal structure by interposing a barrier layer between the beryllium and selenium.
  • Still another object of our invention is to provide a smooth polished uniform substrate for the selenium without a substantial increase in X-ray absorption.
  • Yet another object of our invention is to provide a thin smooth uniform metallic substrate for the selenium that is an exact replica of the original beryllium surface which inay be more readily polished than the refractory berylrum.
  • a further object of our invention is to provide a thin, metallic, thermally conductive substrate which will also meet the requirements of low X-ray absorption and a smooth uniform surface.
  • a still further object of our invention is to provide a smooth, uniform, thermally conductive sulbstrate for the selenium without a substantial increase in X-ray absorption.
  • FIG. 1 is a partial sectional view of the basic beryllium faceplate structure for an X-ray vidicon;
  • FIG. 2a is an enlarged sectional view of one embodiment of an Xray vidicon subassembly having particular applicability to the basic structure;
  • FIG. 2b is an enlarged partial sectional view of an X-ray vidicon using the subassembly of FIG. 2a;
  • FIG. 3a is a sectional view of another embodiment of a subassembly having particular applicability to the basic structure
  • FIG. 3b is an enlarged partial sectional view of an X-ray vidicon using the subassembly of FIG. 30;
  • FIG. 4 represents an enlarged partial sectional View of a further embodiment of our novel X-ray vidicon beryllium faceplate structure
  • FIG. 5 represents an enlarged partial sectional View of still another embodiment of our novel X-ray vidicon beryllium faceplate structure wherein the subassembly is in direct contact with the beryllium window, and
  • FIG. 6 represents a sectional view of a schematic representation of our novel beryllium window structure as used in a typical X-ray vidicon.
  • FIG. 1 there is shown the basic structure which utilizes a beryllium window in an X-ray vidicon.
  • an envelope 10 is shown having aflixed at one end thereof a cylindrical L-shaped flanged ring 12 made of Kovar or other similar material having a coefficient of thermal expansion approximately similar to the expansion coefiicient of glass or other material used for the envelope wall.
  • Ring 12 is sealed into wall 10 by any of the many standard glass-to-metal sealing techniques.
  • the main portion of ring 12 has a configuration which substantially conforms to the end of envelope 10.
  • both the Kovar-to-Kovar seal and the beryllium-to-Kovar seal may be accomplished by any one of the standard techniques, many of which are well known in the art and, hence, any exegesis is unnecessary.
  • the beryllium window 16 in the form of a disc, is brazed in vacuum to a Kovar ring 14 using B.T. or similar braze material.
  • Kovar ring 12 which has been previously sealed to envelope 10, may then be soldered to the Kovar-beryllium window assembly (14 and '16) at the outside periphery of ring 14 and ring 12, using a low melting point solder such as indium-tin alloy.
  • Kavor ring 14 has been described as sealed to ring 12 by means of an indium-tin alloy, it will be obvious to those skilled in the art that these two elements may also be sealed by heliarc weld. This latter weld has the advantage of high mechanical strength as well as the ability to withstand temperatures in excess of the melting point of the previously discussed braze materials. However, this is a most diflicult operation to perform.
  • FIGS. 2a and 2b there is described another structure having particular applicability to an X-ray vidicon.
  • envelope 10, ring 12, kovar support ring 14 and beryllium faceplate 16 are identical in all respects, both physical and functional, with the structure described in FIG. 1.
  • the X-ray sensitive material has been placed in the tube 3 in a particular manner.
  • FIG. 2b there is shown a thin membrane structure 18 that is prepared by first sputtering a conductive material, such as palladium, platinum, nickel, etc., onto a highly polished glass disc,
  • the coated disc then has a layer of copper deposited thereon to a thickness of about 4-10 microns.
  • This layer may be deposited by any one of many techniques, one of which is electroplating.
  • the resulting copper foil 18 is then removed from the glass, mounted between two supporting rings, 20 and 22, and sealed into position by spot welding around the periphery of rings 20 and 22.
  • the support rings may be of a thickness ranging from 0.002" to 0.005". After trimming the edges of excess foil extending beyond the support rings, the copper foil ring assembly is fired in a reducing atmosphere at about 800 C. to cause the copper to recrystal- ,lize, and thus form an extremely taut membrane with extremely uniform surface characteristics.
  • the whole assembly, consisting of rings 20 and 22 and the taut membrane 18, is then sealed to the underside of supporting ring 14, across the inside diameter thereof.
  • the layer 18 then serves as the substrate for the subsequent layer of photoconductor 24, such as selenium, antimony trisulfide, arsenic sulfides, and arsenic selenides, applied thereto (FIG. 2b).
  • a thin layer 26 of freshly vaporized tin, gold, or aluminum may be interposed between the copper layer 18 and the selenium layer 24 to prevent any possibility of reaction between the copper and selenium. If the additional layer of tin or gold or aluminum is necessary, it is possible to avoid the chemical reaction contamination by depositing interposed layer 26 to a thickness of the order of 700 angstroms.
  • FIGS. 3a and 3b Another method of solving this problem is shown in FIGS. 3a and 3b.
  • a metallic ring 28 is provided of the order of 0.02" thick.
  • a nitrocellulose membrane 30 Onto ring 28 there is placed a nitrocellulose membrane 30.
  • Layer 26, which may be nickel, aluminum, gold, or other easily evaporated, low vapor pressure material is then deposited onto the membrane 30.
  • ring 28 acts as a support for the assembly of newly vaporized material 26 and membrane 30. The assembly is then baked at an appropriate temperature to remove the membrane and, in the case of nitrocellulose, a temperature of 400 C.
  • photoconductor layer 24 may be evaporated or deposited on layer 26, the result being a very smooth, taut member consisting of nickel, aluminum, gold, or other easily evaporated, low vapor pressure material, supported by a metal ring with the photoconductor 24 being placed on the surface of the taut member.
  • the whole assembly is then welded or clamped into position against kovar ring 14, as shown in FIG. 3b.
  • FIG. 4 there is shown a glass or mica disc 36, approximately mils thick, interposed between beryllium faceplate 16 and photoconductor 24.
  • a thin conductive material 26 which may consist of aluminum, tin, or gold (or other vaporizable metallic material) to act as a conductive coating for selenium layer 24.
  • Another version of this embodiment which will now become obvious involves preparing the glass disc in a manner similar to the production of an Image Orthicon glass target. That is, a large bubble of glass is blown wherein the thickness of the glass is of the order of 0.0001". Thereafter, a ring, preferably nickel-iron, is provided on which the thin glass is stretched and afiixed. Thereafter, the intermediate metallic layer 26 is provided on the glass surface and the photoconductor layer 24 deposited on the metallic layer 26.
  • the blown glass substrate 36 that is used is completely devoid of marks that usually are found in glass of such small thickness.
  • FIG. 5 there is shown a structure eminently suited for use in a beryllium faceplate X-ray vidicon.
  • the photoconductor layer 24 is vaporized directly onto the beryllium, a large percentage of selenium recrystallizes from the desirable amorphous state to a much less desirable low resistivity crystalline form. It, therefore, becomes necessary to provide means for preventing the reaction between the beryllium and photoconductor. This may be done by interposing a layer of vaporized tin 26 between the beryllium faceplate 16 and the photoconductor layer 24.
  • This layer of tin satisfies all the requirements for the barrier layer in that it provides low X-ray absorption, it may be easily vaporized without the formation of lumps, it is non-reactive with beryllium and, lastly, ithas been found to be non-reactive with the photoconductor. While gold and aluminum also work well, we have found that tin is preferable.
  • FIG. 6 shows, for example, the embodiment of FIG. 2b incorporated in a completed device.
  • the basic structure 13 is shown wherein ring 12 is embedded in wall 10, as previously described.
  • the wall 10 and the structure 13 together comprise a vacuum-type envelope having an electron gun 40 mounted in one end thereof.
  • the components that make up gun 40 include the usual cathode 42, control electrode 44, and one or more accelerating electrodes 46, all of which are connected to lead-in means 48 in a well-known manner.
  • An electron beam 50 emanating from gun 40 is directed onto the target of photoconductive material 24 at the other end of envelope 10, and means is provided for focusing beam 50 and scanning it over the photoconductor 24.
  • Such means may include a focussing coil 52, a deflection yoke 54, and an alignment coil 56, all of which are arranged approximately as shown.
  • Another electrode such as grid 58 having a suitable potential applied thereon is positioned adjacent a photoconductive material 24 and, in operation, functions cooperatively with focussing coil 52 to insure that electron beam 50, in its final approach to the surface 24, is normal thereto.
  • a final accelerating electrode 60 is also provided and may take the form of a metallic cylinder or a conductive coating painted on the interior wall 10.
  • the lead-in means are provided for the purpose of connecting electrode 60 as well as the gun electrodes 42, 44, and 46 to the appropriate source of electrical potential located externally of the tube.
  • An X-ray sensitive electron discharge device comprising an evacuated dielectric envelope, a source of electrons in one end of the envelope, and a faceplate assembly sealing the opposite end of the envelope, said faceplate assembly comprising a beryllium disc on the outer surface thereof, said disc being transparent to X-radiation and opaque to visible light, a layer of X-ray sensitive photoconductive material on the inner surface thereof, said material being noncompatible with beryllium and being exposed to electrons from said source, and means between said beryllium disc and photoconductive material for preventing reaction between the photoconductive material and the beryllium disc.
  • An X-ray sensitive electron discharge device comprising an evacuated dielectric envelope, a source of electrons in one end of the envelope, and a faceplate assembly sealing the opposite end of the envelope, said faceplate assembly comprising a beryllium disc on the outer surface thereof, said 1 sc being transparent to X-tna diatio-n and opaque to visible light, a layer of X-ray sensitive photoconductive material on the inner surface thereof, said material being noncompatible with beryllium and being exposed to electrons from said source, said photoconductive material being spaced from said beryllium disc to prevent reaction therebetween.
  • An X-ray sensitive electron discharge device comprising an evacuated dielectric envelope, a source of electrons in one end of the envelope, and a faceplate assembly sealing the opposite end of the envelope, said faceplate assembly comprising an annular metal structure sealed at one end to the end of the envelope, a beryllium disc sealed to and closing the opposite end of the structure, and a layer of photoconductive material on the inner surface of the faceplate assembly and exposed to electrons from said source, said photoconductive material being noncompatible with beryllium and being supported at a point inwardly removed from said beryllium disc, and means between the beryllium disc and photoconductive material for preventing reaction therebetween.
  • annular structure comprises a first ring sealed to the end of the envelope, and a second ring sealed to one side of the beryllium disc, the rings being sealed together in a manner having an annular portion of the second ring extending inwardly of the structure, the photoconductive material being supported by an annulus secured to said exposed portion of the second ring.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US191099A 1962-04-30 1962-04-30 X-ray vidicon target assembly Expired - Lifetime US3271608A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
NL292137D NL292137A (xx) 1962-04-30
US191099A US3271608A (en) 1962-04-30 1962-04-30 X-ray vidicon target assembly
US191085A US3287581A (en) 1962-04-30 1962-04-30 X-ray vidicon tube having screen hermetically sealed to envelope
GB15818/63A GB978878A (en) 1962-04-30 1963-04-22 X-ray vidicon
FR932829A FR1355262A (fr) 1962-04-30 1963-04-26 Fenêtre pour tube vidicon à rayons x
DE19631464377 DE1464377A1 (de) 1962-04-30 1963-04-27 Vidikon-Bildwandlerroehre zur Aufnahme von Roentgenbildern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US191099A US3271608A (en) 1962-04-30 1962-04-30 X-ray vidicon target assembly

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US3271608A true US3271608A (en) 1966-09-06

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US191099A Expired - Lifetime US3271608A (en) 1962-04-30 1962-04-30 X-ray vidicon target assembly

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US (1) US3271608A (xx)
DE (1) DE1464377A1 (xx)
GB (1) GB978878A (xx)
NL (1) NL292137A (xx)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517241A (en) * 1966-08-31 1970-06-23 Japan Broadcasting Corp Photoconductive target comprising aluminum,selenium and arsenic triselenide layers
US3872344A (en) * 1972-09-15 1975-03-18 Tokyo Shibaura Electric Co Image pickup tube
US3876897A (en) * 1970-07-30 1975-04-08 Kahl Paul Mounting of electrode targets in storage tubes
US4007376A (en) * 1975-08-07 1977-02-08 Samuel Morton Zimmerman Video x-ray imaging system and method
US4057745A (en) * 1974-06-24 1977-11-08 Albert Richard D Scanning X-ray source
US5023896A (en) * 1988-05-27 1991-06-11 Hitachi-Medical Corporation X-ray television apparatus

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2531267A1 (fr) * 1982-07-30 1984-02-03 Labo Electronique Physique Photocathode pour entree de tube electronique comportant un dispositif semi-conducteur avec photoemission par transmission et procede de construction de ladite photocathode
JP2793618B2 (ja) * 1989-02-03 1998-09-03 株式会社日立製作所 撮像管
US5567929A (en) * 1995-02-21 1996-10-22 University Of Connecticut Flat panel detector and image sensor
CN114178639B (zh) * 2022-02-17 2022-05-17 太原理工大学 一种用于铍窗和不锈钢基座的脉冲激光钎焊封接方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2804561A (en) * 1948-03-09 1957-08-27 Sheldon Edward Emanuel X-ray camera
US2866114A (en) * 1953-06-12 1958-12-23 Philips Corp Beryllium window x-ray tube
US2919362A (en) * 1958-04-21 1959-12-29 Dunlee Corp Stabilized x-ray generator
US2951962A (en) * 1959-05-22 1960-09-06 Rca Corp Pickup tube assembly
US2989662A (en) * 1958-11-13 1961-06-20 Fairchild Camera Instr Co Radiographic device
US3061664A (en) * 1959-11-13 1962-10-30 Kimble Glass Co Glass-to-metal seals and method of fabricating same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2804561A (en) * 1948-03-09 1957-08-27 Sheldon Edward Emanuel X-ray camera
US2866114A (en) * 1953-06-12 1958-12-23 Philips Corp Beryllium window x-ray tube
US2919362A (en) * 1958-04-21 1959-12-29 Dunlee Corp Stabilized x-ray generator
US2989662A (en) * 1958-11-13 1961-06-20 Fairchild Camera Instr Co Radiographic device
US2951962A (en) * 1959-05-22 1960-09-06 Rca Corp Pickup tube assembly
US3061664A (en) * 1959-11-13 1962-10-30 Kimble Glass Co Glass-to-metal seals and method of fabricating same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517241A (en) * 1966-08-31 1970-06-23 Japan Broadcasting Corp Photoconductive target comprising aluminum,selenium and arsenic triselenide layers
US3876897A (en) * 1970-07-30 1975-04-08 Kahl Paul Mounting of electrode targets in storage tubes
US3872344A (en) * 1972-09-15 1975-03-18 Tokyo Shibaura Electric Co Image pickup tube
US4057745A (en) * 1974-06-24 1977-11-08 Albert Richard D Scanning X-ray source
US4007376A (en) * 1975-08-07 1977-02-08 Samuel Morton Zimmerman Video x-ray imaging system and method
US5023896A (en) * 1988-05-27 1991-06-11 Hitachi-Medical Corporation X-ray television apparatus

Also Published As

Publication number Publication date
GB978878A (en) 1964-12-23
DE1464377B2 (xx) 1970-07-30
NL292137A (xx)
DE1464377A1 (de) 1969-10-09

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