US3769059A - X-ray and gamma-ray scintillators and detector screens incorporating same - Google Patents

X-ray and gamma-ray scintillators and detector screens incorporating same Download PDF

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Publication number
US3769059A
US3769059A US00100564A US3769059DA US3769059A US 3769059 A US3769059 A US 3769059A US 00100564 A US00100564 A US 00100564A US 3769059D A US3769059D A US 3769059DA US 3769059 A US3769059 A US 3769059A
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Prior art keywords
substrate
layer
scintillator
ray
screen
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Expired - Lifetime
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US00100564A
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English (en)
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B Driard
G Roziere
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Thales SA
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Thomson CSF SA
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • 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

Definitions

  • ABSTRACT An X ray or gamma-ray scintillator comprising, on a substrate, an alkaline halide layer of fibrous structure having the needle form, with the needles perpendicular to the surface of the substrate, the scintillator being associated, in detector screens of imageintensifier tubes for X-ray or gamma-ray, with a photo-sensitive layer enshrouding said needles.
  • the present invention relates to the design of X-ray and gamma-ray scintillators.
  • An X-ray or gamma-ray image-intensifier tube comprises, within an evacuated envelope, two screens which are generally situated at the two ends of the envelope, one being the detector screen and the other the display screen.
  • the detector screen of the tube On the path of the incident beam of radiation, there are disposed in succession the object and the imageintensifier tube, the detector screen of the tube being located opposite the object. This screen receives the radiation which has passed through the object.
  • the detector screen comprises, at the object side, a layer which is referred to as the luminescent or scintillation layer and capable of emitting photons within the luminous radiation range, this being referred to as luminous photons and this emission taking place under the effect of the radiation received from the object and a photo-sensitive layer which emits electrons under the effect of said photons, this layer being referred to as a photocathode.
  • the means required are in addition provided in the tube in order to accelerate and focus onto the display screen, the electrons emitted by the photocathode in this fashion an image of the object is produced by bombardment of said screen.
  • the object of the present invention is to design scintillators of alkaline halides, which are thicker than those of the prior art but nevertheless exhibit good adhesion to their substrate and good stability in operation.
  • the invention is applicable, amongst other things, to the composite detector screens of X-ray and gammaray image-intensifier tubes as hereinbefore described, which comprise an alkaline halide luminescent layer for example of cesium iodide, potassium iodide, sodium with one or more activators such as thallium or sodium deposited by vaporisation under vacuum on a substrate, and a photo-sensitive layer of one of the known materials such as complex compounds of antimony and alkaline metals, cesium, potassium, sodium, rubidium.
  • an alkaline halide luminescent layer for example of cesium iodide, potassium iodide, sodium with one or more activators such as thallium or sodium deposited by vaporisation under vacuum on a substrate
  • a photo-sensitive layer of one of the known materials such as complex compounds of antimony and alkaline metals, cesium, potassium, sodium, rubidium.
  • the invention is based upon the observation, stemming from work carried out in the laboratories of the applicants, that the adhesion of the scintillator layer to its substrate is improved if said scintillator layer has a fibrous structure obtained by successive operations of vaporisation under vacuum of the constituent material of said layer onto a substrate which is maintained at a low temperature, each of said vaporising operations giving rise to the deposition of a stratum forming part of the ultimate layer, the fibres of the structure thus obtained naturally being orientated substantially perpendicularly to the surface of the substrate.
  • This structure furthermore, exhibits a variety of advantages which will be described in the following.
  • the present invention relates to an X-ray or gammaray scintillator constituted by an activated luminescent layer whose fundamental constituent is made of alkaline halides and deposited upon a substrate, characterised in that said luminescent layer is essentially consti-' tuted by needles disposed substantially perpendicularly to said substrate.
  • FIG. 1 is a schematic sectional view illustrating the main elements of an X-ray or gamma-ray image intensifier tube
  • FIG. 2 is a schematic sectional view illustrating the principal elements of an installation employed in the manufacture in accordance with the invention, of the detector screen of the tube shown in FIG. 1
  • FIG. 3 is a sectional view on an enlarged scale, of part of the detector screen of FIG. 2.
  • FIG. 1 which illustrates an example of how the invention may be applied
  • an evacuated envelope 1 in the neighbourhood of the extremities thereof, a detector screen 2, a display screen 3 and, between the two, electrodes 4, 5 and 6 for the control and focusing of the electron beam,the latter being symbolised by oblique lines issuing in operation from the screen 2 and directed onto the screen 3.
  • screen 2 is located in the path of the X-ray or gamma radiation, indicated by arrows, opposite the object 7 whose image is to be displayed on the screen 3.
  • the detector screen 2 to which the invention is applied essentially comprises, on a substrate, so called screen substrate, a luminescent layer sensitive to the incident radiation from the object, and a photosensitive layer facing the fluorescent display screen and emitting electrons towards the same as already indicated hereinbefore.
  • the substrate of the screen 2 is merged into the front face 10 of the envelope 1.
  • FIG. 2 illustrates the diagram of an installation for deposition by vaporization under vacuum, this being the process employed for the manufacture, in accordance with the invention, of the detector screens of tubes such as that shown in FIG. 1 1 inside an envelope in which a vacuum is maintained by a pump 21, there are placed a screen substrate in the form of a spherical dish, carrying a lining 32 to which reference will be made hereinafter and whose thickness has been shown very much exagerated, and a vaporiser consisting of a crucible 22 containing the material 24 of which is made the luminescent layer of the ultimate screen, an alkaline halide in fact, surrounded by a heater resistor 23 for producing the requisite vaporising temperature the vaporised material condenses on the screen substrate 30, 32.
  • the deposition of the luminescent layer 31 takes place in the: form of successive vaporising operations of limited duration, in
  • the maximum permissible temperature in accordance with the invention which the screen substrate should reach during the course of these operations is about 150C.
  • the component having the shape shown at 25 and containing passages 26 through which a cooling fluid is circulated.
  • a layer of alkaline halides 31 of f1- brous structure having the needle form 40 Illustrated at an enlarged scale in FIG. 3, with the needles perpendicular to the surface of the substrate in the direction of the cross-hatching in FIG. 2, is obtained.
  • These needles which have diameters ranging between 5 and 10 p at their bases, are arranged side by side at the base level and separated by gaps 41 of less than 1 u. (this is proved by microscopic examination).
  • their density is between 85 and 95 percent of that of the crude product 24.
  • the layer 32 is designed to promote the bonding of V the needles 40 to halide layer 31.
  • It is designed by a method which depends upon the nature of the element of which it is made and upon the nature of the substrate 30. In particular it may itself be produced by vaporising, utilising the same installation.
  • Luminescent layer or scintillator (31) Screen substrate (30) spherical glass dish, 5/10 mm thick and 160 mm radius.
  • Vaporization carried out under a vacuum in the order of lO mm/hg.
  • the bonding of the nickel to the glass substrate 30 can be improved by toughening the glass in a hydrofluoric bath containing 10 percent HF or F HNI-I
  • the photo-sensitive layer 34 is only deposited upon the layer of scintillator 31, after the incorporation of the screen (which at this stage comprises the substrate, the intermediate layer and the scintillator layer) in the tube, the latter already being equipped with the display screen and all the other electrodes.
  • This layer itself is produced by the vaporising of antimony and alkaline metals at a temperature of around 100C.
  • the substrate 30 could be made of metal instead of glass, for example of aluminum or beryllium and have a thickness in the same order as that of a glass substrate, being covered on that of its faces in contact with the scintillator with an oxide layer 5 to 10 M in thickness obtained in that case by anodising in the case of a glass substrate
  • the intermediate layer 32 may also consist of an alloy of Fe, Ni, Co, already known in the art in the context of electronic tubes by the name of FERNICO of stainless steel or of -20 nickel-chrome with a thickness in the same order as that of the nickel layer of the foregoing example.
  • the fibrous structure of the halide layer constituting the scintillator provides mechanical flexibility, enabling this layer to follow distortions of the substrate which are liable to occur during operation which flexibility is very considerable.
  • the scintillators in accordance with the invention will in other words tolerate a much larger thickness without deterioration and likewise a greater temperature difference between the assembly of substrate and intermediate layer, 30 32, and the halide layer, than will prior art screens, both these factors being in line with the objectives set out hereinbefore.
  • the needle-like halide layers of the invention it is possible to choose substrates of plastic material which have a coefficient of expansion in the order of 1,000 X lO' /C, which value is substantially higher than that of cesium iodide which is in the order of approximately 510 X 10 /C, without any drawbacks being incurred as far as the luminescent layer is concerned.
  • the use of plastic materials has the advantage of enabling large-sized screens to be produced which have a predetermined geometric profile produced by polymerisation or moulding.
  • the screens in accordance with the invention furthermore, provide improved spatial resolution, the light produced by excitation of X-ray or gamma-radiation in the luminescent layer, being for the major part channeled through. the needles, with no surface diffusion.
  • the design of the photosensitive layer 34 (FIG. 3) of the detector screen is itself facilitated by the structure of the luminescent layer 31, same Figure the photo-sensitive material enshrouds the tips 42 of the needles 40 and this improves its bonding to the luminescent layer 31.
  • the layer 34 lays down onto the top of the needles in the interstices 43 between the needles 40. At the same time, the probability of the collection by the photo-sensitive layer of light photons generated in the luminescent layer, is increased.
  • the present invention which has been described in the context of a scintillator forming an integral part of a screen with a photo-emissive photo-sensitive layer, itself incorporated in an X-ray or gamma-ray imageintensifier tube, relates more generally to all devices which incorporate a scintillator in accordance with the invention.
  • the scintillator is incorporated into a screen which also comprises a photo-sensitive layer, it extends equally to the case where same is photoemissive or photo-conductive.
  • An X ray or "y ray scintillator capable of emitting photons within the luminous radiation range when exposed to X or 'y ray comprising a substrate transparent for said X or 'y ray and a luminescent layer deposited onto said substrate, said luminescent layer being made of alkaline halides having a fibrous structure constituted by tapered bodies having their bases applied side by side onto said substrate and extending substantially perpendicularly beyond the surface of said substrate.
  • a scintillator as claimed in claim 1 further comprising between said substrate and said fibrous alkaline halide luminescent layer, an intermediate layer made of a material which is transparent to x-rays or gamma-rays and which facilitates the bonding of said luminescent layer to said substrate.
  • a detector screen for X or 'y ray image-intensifier tubes comprising a scintillator in accordance with claim 1 and a photo-sensitive layer deposited onto said luminescent layer of said scintillator.
  • a method of producing a scintillator capable of emitting photons within the luminous radiation range when exposed to X or y ray comprising a substrate transparentfor said X or y ray and a luminescent layer deposited onto said substrate, said luminescent layer being made of alkaline halides having a fibrous structure constituted by tapered bodies having their bases applied side by side onto said substrate and extending substantially perpendicularly beyond the surface of said substrate consisting in vaporizing said alkaline halide onto said substrate in an evacuated enclosure enclosing said substrate and said alkaline halide to be vaporized, said vaporization being made in several steps while said substrate is permanently cooled by cooling means disposed within said enclosure to provide cooling of the face of said substrate where no alkaline halide is deposited, thus assuming a temperature of said substrate never in excess of C.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Measurement Of Radiation (AREA)
US00100564A 1969-12-30 1970-12-22 X-ray and gamma-ray scintillators and detector screens incorporating same Expired - Lifetime US3769059A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR6945437A FR2075856A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1969-12-30 1969-12-30

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DE (1) DE2064466A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2075856A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1311550A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4011454A (en) * 1975-04-28 1977-03-08 General Electric Company Structured X-ray phosphor screen
DE2721280A1 (de) * 1976-05-11 1977-11-17 Tokyo Shibaura Electric Co Eingangsbildschirm fuer einen bildverstaerker
US4059768A (en) * 1975-04-15 1977-11-22 Agfa-Gevaert N.V. Radiographic intensifying screens
DE2734799A1 (de) * 1976-08-03 1978-02-23 Thomson Csf Radiologischer bildverstaerker
US4117365A (en) * 1977-01-14 1978-09-26 General Electric Company Continous photocathode for x-ray radiography having two-dimensional array of apertures
DE2813919A1 (de) * 1977-04-01 1978-10-05 Hitachi Electronics Eingangs-bildschirm fuer roentgen- fluoreszenzvervielfacher
US4147949A (en) * 1977-01-14 1979-04-03 General Electric Company Apparatus for X-ray radiography
US4147948A (en) * 1977-01-14 1979-04-03 General Electric Company Apparatus for X-ray radiography
US4415605A (en) * 1980-10-24 1983-11-15 General Electric Company Scintillator screen method of manufacture
US4437011A (en) 1980-06-16 1984-03-13 Tokyo Shibaura Denki Kabushiki Kaisha Radiation excited phosphor screen and method for manufacturing the same
US4528210A (en) * 1980-06-16 1985-07-09 Tokyo Shibaura Denki Kabushiki Kaisha Method of manufacturing a radiation excited input phosphor screen
US4820926A (en) * 1986-03-19 1989-04-11 U.S. Philips Corporation Radiation conversion screen
US5012103A (en) * 1988-10-28 1991-04-30 Hamamatsu Photonics Kabushiki Kaisha Radiation detector
US20110210254A1 (en) * 2010-03-01 2011-09-01 Siemens Aktiengesellschaft Method for producing a scintillator and scintillator
CN102194536B (zh) * 2010-03-01 2016-12-14 西门子公司 用于制造闪烁器的方法和闪烁器
US10422888B1 (en) * 2015-07-17 2019-09-24 Triad National Security, Llc Scintillation detectors

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7703295A (nl) * 1977-03-28 1978-10-02 Philips Nv Roentgendetektor.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752521A (en) * 1953-04-09 1956-06-26 Henry F Ivey Screen material
US3275827A (en) * 1963-12-16 1966-09-27 Harshaw Chem Corp Detector utilizing a scintillator and photoconductive material
US3515587A (en) * 1963-04-06 1970-06-02 Bausch & Lomb Method for changing the optical characteristics of an article
US3558893A (en) * 1967-01-30 1971-01-26 Picker Corp X- and gamma-ray sensitive image intensification tube

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2752521A (en) * 1953-04-09 1956-06-26 Henry F Ivey Screen material
US3515587A (en) * 1963-04-06 1970-06-02 Bausch & Lomb Method for changing the optical characteristics of an article
US3275827A (en) * 1963-12-16 1966-09-27 Harshaw Chem Corp Detector utilizing a scintillator and photoconductive material
US3558893A (en) * 1967-01-30 1971-01-26 Picker Corp X- and gamma-ray sensitive image intensification tube

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4059768A (en) * 1975-04-15 1977-11-22 Agfa-Gevaert N.V. Radiographic intensifying screens
US4069355A (en) * 1975-04-28 1978-01-17 General Electric Company Process of making structured x-ray phosphor screen
US4011454A (en) * 1975-04-28 1977-03-08 General Electric Company Structured X-ray phosphor screen
DE2721280A1 (de) * 1976-05-11 1977-11-17 Tokyo Shibaura Electric Co Eingangsbildschirm fuer einen bildverstaerker
US4287230A (en) * 1976-08-03 1981-09-01 Thomson-Csf Process for producing a scintillator screen
DE2734799A1 (de) * 1976-08-03 1978-02-23 Thomson Csf Radiologischer bildverstaerker
US4398118A (en) * 1976-08-03 1983-08-09 Thomson - Csf X-Ray image intensifier
US4117365A (en) * 1977-01-14 1978-09-26 General Electric Company Continous photocathode for x-ray radiography having two-dimensional array of apertures
US4147948A (en) * 1977-01-14 1979-04-03 General Electric Company Apparatus for X-ray radiography
US4147949A (en) * 1977-01-14 1979-04-03 General Electric Company Apparatus for X-ray radiography
DE2813919A1 (de) * 1977-04-01 1978-10-05 Hitachi Electronics Eingangs-bildschirm fuer roentgen- fluoreszenzvervielfacher
US4437011A (en) 1980-06-16 1984-03-13 Tokyo Shibaura Denki Kabushiki Kaisha Radiation excited phosphor screen and method for manufacturing the same
US4528210A (en) * 1980-06-16 1985-07-09 Tokyo Shibaura Denki Kabushiki Kaisha Method of manufacturing a radiation excited input phosphor screen
US4415605A (en) * 1980-10-24 1983-11-15 General Electric Company Scintillator screen method of manufacture
US4820926A (en) * 1986-03-19 1989-04-11 U.S. Philips Corporation Radiation conversion screen
US5012103A (en) * 1988-10-28 1991-04-30 Hamamatsu Photonics Kabushiki Kaisha Radiation detector
US20110210254A1 (en) * 2010-03-01 2011-09-01 Siemens Aktiengesellschaft Method for producing a scintillator and scintillator
CN102194536A (zh) * 2010-03-01 2011-09-21 西门子公司 用于制造闪烁器的方法和闪烁器
US8618488B2 (en) * 2010-03-01 2013-12-31 Siemens Aktiengesellschaft Method for producing a scintillator and scintillator
CN102194536B (zh) * 2010-03-01 2016-12-14 西门子公司 用于制造闪烁器的方法和闪烁器
US10422888B1 (en) * 2015-07-17 2019-09-24 Triad National Security, Llc Scintillation detectors

Also Published As

Publication number Publication date
FR2075856A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1971-10-15
DE2064466A1 (de) 1971-07-01
GB1311550A (en) 1973-03-28

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