WO2021256179A1 - Plaque de scintillateur, dispositif de détection de rayonnement, système de détection de rayonnement et procédé de fabrication de plaque de scintillateur - Google Patents

Plaque de scintillateur, dispositif de détection de rayonnement, système de détection de rayonnement et procédé de fabrication de plaque de scintillateur Download PDF

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Publication number
WO2021256179A1
WO2021256179A1 PCT/JP2021/019559 JP2021019559W WO2021256179A1 WO 2021256179 A1 WO2021256179 A1 WO 2021256179A1 JP 2021019559 W JP2021019559 W JP 2021019559W WO 2021256179 A1 WO2021256179 A1 WO 2021256179A1
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Prior art keywords
scintillator
needle
copper
substrate
scintillator plate
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PCT/JP2021/019559
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English (en)
Japanese (ja)
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智之 大池
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キヤノン株式会社
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • 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
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K4/00—Conversion screens for the conversion of the spatial distribution of X-rays or particle radiation into visible images, e.g. fluoroscopic screens

Definitions

  • the present invention relates to a scintillator plate, a radiation detection device, a radiation detection system, and a method for manufacturing a scintillator plate.
  • FPD flat panel detector
  • a scintillator that converts radiation into light
  • needle-like crystals of alkali metal halide compounds such as cesium iodide are widely used in order to efficiently transmit the light converted from radiation to a light receiving element.
  • a void is formed between the acicular crystals adjacent to each other, and light repeats total internal reflection in the acicular crystal due to the difference in the refractive index between the acicular crystal and air.
  • Patent Document 1 in order to improve the resolution of the scintillator, the crystallinity of the needle-shaped crystals at the initial stage of film formation is improved, and the thickness of the needle-shaped crystals is reduced to suppress the size of the needle-shaped crystals. It is shown.
  • Patent Document 1 shows that the thickness of the needle-shaped crystal increases as the needle-shaped crystal grows.
  • the voids between the needle-shaped crystals at the initial stage of film formation are compared with the case where the thickness of the needle-shaped crystals is not reduced. , May increase.
  • the voids between the needle-shaped crystals increase, the filling rate of the needle-shaped crystals may decrease, and the detection quantum efficiency (DQE) for converting radiation into light may decrease.
  • DQE detection quantum efficiency
  • An object of the present invention is to provide an advantageous technique for improving the resolution of a scintillator and suppressing a decrease in detection quantum efficiency.
  • the scintillator plate according to the embodiment of the present invention is a scintillator plate in which a scintillator is arranged on a main surface of a substrate, and the scintillator is a plurality of scintillators containing a halogenated alkali metal compound as a base material.
  • Each of the plurality of needle-shaped crystals is arranged between the needle-shaped crystal portion to which copper is added and the main surface and the needle-shaped crystal portion, and is arranged from the needle-shaped crystal portion. It is also characterized by containing an initial growth portion in which the amount of copper added is small.
  • the above means provides an advantageous technique for improving the resolution of the scintillator and suppressing the decrease in the detection quantum efficiency.
  • the figure which shows the structural example of the radiation detection apparatus using the scintillator of FIG. The figure which shows the structural example of the radiation detection apparatus using the scintillator of FIG. It is a figure which shows the structural example of the radiation detection system using the radiation detection apparatus of FIGS. 9A and 9B.
  • the radiation in the present invention includes beams having the same or higher energy, for example, X, in addition to ⁇ rays, ⁇ rays, ⁇ rays, etc., which are beams produced by particles (including photons) emitted by radiation decay. It can also include lines, particle rays, cosmic rays, etc.
  • FIG. 1 is a diagram showing a cross-sectional structure of the scintillator plate 100 in the present embodiment.
  • the scintillator 105 is arranged on the main surface 106 of the substrate 101.
  • the scintillator 105 contains a plurality of acicular crystals 103 containing an alkali metal halide as a base material.
  • Each of the plurality of needle-shaped crystals 103 is arranged between the needle-shaped crystal portion 104 to which copper is added and between the main surface 106 and the needle-shaped crystal portion 104, and the amount of copper added is larger than that of the needle-shaped crystal portion 104. Includes a small number of initial growth portions 102.
  • the initial growth unit 102 does not have to contain copper.
  • the fact that copper is not contained may mean that copper is not completely added. Further, the fact that copper is not contained may include a case where the copper contained in the initial growth portion 102 cannot be measured in reality. Therefore, the fact that the initial growth section 102 does not contain copper may mean that the initial growth section 102 contains copper that is equal to or less than a quantifiable lower limit when measuring the composition of the initial growth section 102 using, for example, a fluorescent X-ray analyzer.
  • the lower limit of quantifiable copper in the fluorescent X-ray analyzer is, for example, about 0.01 to 0.1 mol% (100 to 1000 ppm).
  • the fact that the initial growth section 102 does not contain copper may mean that the initial growth section 102 contains copper that is equal to or less than a detectable lower limit when measuring the composition of the initial growth section 102 using a fluorescent X-ray analyzer.
  • the lower limit of copper detection in the fluorescent X-ray analyzer is, for example, about 1 to 10 ppm.
  • the scintillator 105 is formed on the main surface 106 of the substrate 101 by vacuum vapor deposition or the like.
  • the initial growth portion 102 is a portion formed on the main surface 106 of the substrate 101 immediately after the start of film formation. That is, in the initial growth portion 102, the material of the scintillator 105 becomes vapor-deposited particles and flies onto the main surface 106 of the substrate 101 to generate an initial nucleus that is the basis of the needle-shaped crystal 103, and has a certain size. It is a region that grows into crystal particles. Therefore, the initial growth portion 102 is a region in which the specific shape and crystal orientation have not yet been clearly determined.
  • the particle size of the particle size of the initial growth portion 102 may be in the range of about 0.2 ⁇ m or more and 1.5 ⁇ m or less.
  • FIG. 2 is a diagram showing a cross-sectional structure showing a scintillator plate 200 as a comparative example with respect to the scintillator plate 100 of FIG.
  • the scintillator 205 is arranged on the main surface 106 of the substrate 101, similarly to the scintillator plate 100.
  • the scintillator 205 contains a plurality of acicular crystals 203 containing an alkali metal halide as a base material. Copper is added to each of the plurality of needle-shaped crystals 203 from the initial growth portion 202 to the needle-shaped crystal portion 204.
  • the initial growth portion 202 may contain more copper than the needle-shaped crystal portion 204.
  • the initial growth portion 202 of the comparative example shown in FIG. 2 a structure is formed in which the crystal particles of the alkali metal halide of the base material are finely divided by the compound 206 containing copper as an additive material.
  • the column diameter of the needle-shaped crystal portion 204 formed on the initial growth portion 202 can be miniaturized and good crystallinity can be realized.
  • the crystal particles forming the initial growth portion 102 shown in FIG. 1 do not contain copper as an additive material, the particle size increases as the crystal grows.
  • the maximum thickness of the initial growth portion 102 is approximately 1.5 ⁇ m or more and 2.5 ⁇ m or less. Copper is added to the acicular crystal portion 104 formed on the initial growth portion 102. Therefore, the expansion of the column diameter in the direction parallel to the main surface 106 of the substrate 101 is suppressed from the time when the addition of copper is started.
  • the scintillator plate 100 can suppress the void portion between the needle-shaped crystals 103 as compared with the scintillator plate 200 shown in FIG.
  • the scintillator plate 100 can improve the decrease in the filling rate of the scintillator 105. That is, the scintillator plate 100 shown in the present embodiment can improve the resolution of the scintillator and suppress the decrease in the detection quantum efficiency.
  • the base material of the scintillator 105 can be selected from halogenated alkali metal compounds capable of forming acicular crystals 103, such as cesium iodide and cesium bromide. Further, an activator for imparting a light emitting function may be added to the scintillator 105.
  • the activating material for example, by containing 0.2 mol% or more and 3.2 mol% or less of thallium iodide, thallium bromide, etc. with respect to the base material, the thallium functions as a light emitting center and imparts a sufficient light emitting function. become able to. That is, each of the plurality of needle-shaped crystals 103 may contain thallium.
  • the acicular crystal portion 104 contains copper as an additive material.
  • the concentration of copper in the needle-shaped crystal portion 104 may be 0.2 mol% or more and 5.0 mol% or less with respect to the base material. Further, the concentration of copper in the needle-shaped crystal portion 104 may be 0.4 mol% or more and 2.0 mol% or less.
  • a material for adding copper for example, a compound such as copper iodide or copper bromide can be used.
  • FIG. 3 is a diagram showing a configuration example of a film forming apparatus 310 for forming a scintillator plate 100 having a scintillator 105 in the present embodiment.
  • the scintillator plate 100 arranges a material supply source 301 and a substrate 101 for forming a scintillator 105 in a chamber 304 capable of vacuum exhaust as shown in FIG.
  • the scintillator plate 100 is formed by forming the scintillator 105 on the main surface 106 of the substrate 101 by using a film forming method such as a thin film deposition method.
  • the film may be formed while rotating the substrate 101.
  • FIG. 3 is a diagram showing a configuration example of a film forming apparatus 310 for forming a scintillator plate 100 having a scintillator 105 in the present embodiment.
  • the scintillator plate 100 arranges a material supply source 301 and a substrate 101 for forming a scintillator 105 in a chamber
  • the material supply source 301 may be filled with different material supply sources 301a to 301c for each of the materials 302a to 302c used for vapor deposition to form a film.
  • a shutter 303 is required when the material 302b used for vapor deposition is copper iodide, copper bromide, or the like. Copper can be added to an arbitrary film thickness region by opening and closing the shutter 303 between the material supply source 301b filled with the material 302b heated to an arbitrary temperature and the substrate 101 during the film formation. Is.
  • the shutter 303 may be arranged not only between the material supply sources 301b of the amount of the additive material but also between the other material supply sources 301a and 301c and the substrate 101. Further, in FIG. 3, the material 302a for depositing the alkali metal halide compound which is the base material of the scintillator 105 and the material 302c for adding an activator such as thallium are separate material supply sources 301a, respectively. It is filled in 301c. However, the present invention is not limited to this, and the base material and the activator of the scintillator 105 may be filled in one material source 301 as one material 302 for vapor deposition.
  • FIG. 4 is a schematic diagram showing the film forming process of the needle-shaped crystal 103 of the scintillator 105.
  • the arrow 402 indicates the growth direction of the needle-shaped crystal 103.
  • the vapor-filmed particles 403 having thermal energy fly to the surface 401 of the needle-shaped crystal 103, and when the vapor-filmed particles 403 adhere to the surface 401, the vapor-filmed particles 403 have an arrow 404 on the surface 401. Diffuse as shown in.
  • the diffusion distance of the needle-shaped crystal 103 on the surface 401 is suppressed, and the main surface of the substrate 101 is suppressed in the needle-shaped crystal portion 104. It is considered that the expansion of the column diameter in the direction parallel to 106 is suppressed.
  • 5A and 5B are observation images of the surface and the side surface of the scintillator 105.
  • the size and change of the column diameter in the direction parallel to the main surface 106 of the substrate 101 of the needle-shaped crystal 103 of the scintillator 105 are evaluated by a scanning electron microscope (SEM) or the like, and the film surface (FIG. 5A) or the film of the scintillator 105 is evaluated. It can be measured by observing the side surface (FIG. 5B).
  • the film surface of the scintillator 105 refers to the surface of the scintillator 105 on the side opposite to the substrate 101 and on the side of the needle-shaped crystal portion 104.
  • the evaluation of the size and change of the column diameter in the direction parallel to the main surface 106 of the substrate 101 of the needle-shaped crystal 103 of the scintillator 105 can be measured by crystal orientation analysis by electron backscatter diffraction (EBSD).
  • EBSD electron backscatter diffraction
  • the column diameter of the needle-shaped crystal 103 of the scintillator 105 may be the length of the diameter of a circle circumscribing the surface 601 in the direction parallel to the main surface 106 of the substrate 101 of the needle-shaped crystal 103 of the scintillator 105. .. In FIG. 6, 603 is the minor axis of the ellipse 602.
  • FIG. 7 is a diagram showing the relationship between the film thickness of the scintillator 105 and the column diameter in the direction parallel to the main surface 106 of the substrate 101 of the needle-shaped crystal 103.
  • the column diameter increases sharply.
  • the addition of copper is started when the film thickness of the scintillator 105 becomes, for example, 40 ⁇ m, the needle-shaped crystal portion 104 in which the expansion of the column diameter is suppressed grows.
  • the rate of increase in the thickness of the initial growth portion 102 per unit length in the crystal growth direction is the needle-shaped crystal portion per unit length in the crystal growth direction. It can be said that it is larger than the increase rate of the thickness of 104. As shown in FIG. 7, the increase rate of the thickness of the initial growth portion 102 may be at least twice the increase rate of the thickness of the needle-shaped crystal portion 104. In particular, it can be seen that the increase in the column diameter is suppressed in the portion where the needle-shaped crystal 103 has grown, for example, when the film thickness is 200 ⁇ m or more.
  • the filling rate PD [%] of the scintillator 105 is as follows from the weight W [g] of the vapor deposition film, the area A [cm 2 ], the thickness t [cm], and the crystal density d [g / cm 3 ] of the scintillator material. It can be calculated by the calculation formula (1).
  • PD W / (A ⁇ t ⁇ d) ⁇ ⁇ ⁇ (1)
  • the temperature condition of the substrate 101 when forming the scintillator 105 will be described. From the viewpoint of the surface diffusion length of the vapor-filmed particles that have reached the main surface 106 of the substrate 101 to be film-formed, the low temperature of the substrate 101 at the initial stage of film-forming reduces the column diameter of the needle-shaped crystals 103. Of particular importance above.
  • the temperature of the substrate 101 at the initial stage of film formation at the start of vapor deposition of the scintillator 105 may be 60 ° C. or lower.
  • the temperature of the substrate 101 at the initial stage of film formation becomes higher than 130 ° C.
  • the distance of surface diffusion becomes long, the crystal size becomes large, the crystal structure is disturbed, and the gaps between acicular crystals cannot be maintained.
  • the characteristics may not be obtained.
  • the temperature of the substrate 101 at the initial stage of film formation is low, activation of the activator having a light emitting function may be insufficient from the viewpoint of luminance characteristics.
  • the temperature of the substrate 101 is as low as 20 ° C. (for example, room temperature) or less during the film formation, impurities and residual gas are easily taken into the acicular crystal 103 of the scintillator 105, and the crystallinity of the acicular crystal 103 is increased. May get worse.
  • the temperature of the substrate 101 at the time of starting the growth (deposition) of the acicular crystals 103 on the substrate 101 (initial stage of film formation) by using the material of the halogenated alkali metal compound which is the base material of the scintillator 105 is 20.
  • the temperature may be °C or higher and 60 °C or lower.
  • cesium iodide is filled in the material supply source 301a as the material 302a for depositing the alkali metal halide compound which is the base material of the scintillator 105.
  • Thallium iodide is filled in the material source 301c as the material 302c to which the activator is added.
  • Copper iodide is filled in the material supply source 301b as a material 302b for adding copper to the scintillator 105.
  • a plurality of needle-shaped crystals 103 are grown by using the material 302a of the material 302a of the alkali metal halide compound and the material 302b for adding copper to the substrate 101.
  • a step of starting and a step of forming a plurality of acicular crystals 103 using the material 302a and the material 302b after the step of starting the growth are included.
  • a shutter 303 is arranged between the material supply source 301b of the film forming apparatus 310 and the substrate 101 in order to add copper during the growth of the plurality of acicular crystals 103 of the scintillator 105.
  • a shutter 303 may also be arranged between the material supply sources 301a and 301c and the substrate 101.
  • the temperature of the substrate 101 and the temperatures of the respective material supply sources 301a to 301c can be appropriately adjusted according to the vapor deposition conditions.
  • the temperature of the material source 301a is in the range of 670 ° C to 700 ° C
  • the temperature of the material source 301c is 340 ° C.
  • the temperature of the substrate 101 at the initial stage of film formation is set in the range of 20 ° C. to 60 ° C.
  • the vapor deposition step of the scintillator 105 after the supply of cesium iodide and thallium iodide to the substrate 101 is started, the supply of copper iodide for adding copper to the substrate 101 is started.
  • the temperature of the material supply source 301b filled with copper iodide to 520 ° C. or higher, it is possible to form the needle-shaped crystal portion 104 of the needle-shaped crystal 103 in a shape in which an increase in the column diameter is suppressed. Is.
  • the temperature of the substrate 101 is raised to the extent that the crystal structure of the needle-like crystal 103 does not collapse in the latter stage of film formation, and light emission is performed. It is possible to activate the activator responsible for the function and improve the emission brightness. Further, by heat-treating the scintillator 105 at 200 ° C. or lower using an annealing device inside or outside the film forming apparatus 310 after forming the scintillator 105, high resolution and luminance characteristics can be obtained while maintaining the crystal structure of the acicular crystal 103. It is possible to maintain.
  • Alkali metal halide compounds such as cesium iodide show deliquescent properties. Therefore, as a protective film for protecting the scintillator 105 from moisture, a parylene, a fluororesin, a TEOS film, or the like may be formed by using various coating methods such as a spray method, a coating method, and a CVD method.
  • the protective film may be formed in the chamber 304 of the film forming apparatus 310 shown in FIG. 3, or may be formed by taking out the substrate 101 on which the scintillator 105 is formed from the chamber 304.
  • a protective film using parylene covering the scintillator 105 may be formed immediately by using the CVD method.
  • the evaluation of the resolution characteristics can be quantitatively compared by measuring the modulation transfer function (MTF).
  • the detection quantum efficiency (DQE) can be evaluated by using an appropriate photodetector such as a charge-coupled device (CCD) type or a complementary metal oxide semiconductor (CMOS) type or a photodetector such as a camera.
  • the chemical composition of the scintillator 105 can be evaluated by, for example, a fluorescent X-ray analysis method or an inductively coupled plasma analysis method. Crystallinity can be evaluated by, for example, an X-ray diffraction analysis method.
  • FIG. 9 summarizes the characteristics of the scintillator plate 100 in the examples and comparative examples described below. First, a comparative example will be described.
  • the scintillator 205 of the comparative example of the acicular crystal structure using cesium iodide as a base material, copper as an additive element, and thallium as an activator was formed by using the film forming apparatus 310 shown in FIG. It is a thing.
  • a material supply source 301a filled with cesium iodide mixed with copper (CuI) iodide (CuI) at 0.2 wt% was prepared, and as the material 302c, a material supply source 301c filled with thallium iodide was prepared.
  • the material supply sources 301a and 301c and the substrate 101 were arranged in the chamber 304 of the film forming apparatus 310, respectively.
  • the material supply sources 301a and 301c are cylindrical containers made of tantalum.
  • As the substrate 101 a silicon substrate laminated with an aluminum reflective layer having a thickness of 100 nm and silicon oxide having a thickness of 50 nm was used.
  • the scintillator 205 is formed by opening the shutter (not shown) provided between the substrate 101 and the material supply sources 301a and 301c while rotating the substrate 101.
  • the membrane was started.
  • the temperature of the substrate 101 gradually increased from 60 ° C. at the start of film formation to 130 ° C. at the end of film formation.
  • each shutter provided between the substrate 101 and the material supply sources 301a and 301c was closed to complete the film formation. After the film formation was completed, the temperature of the substrate 101 was further raised to 160 ° C.
  • the substrate 101 on which the scintillator 205 was formed was taken out and observed with a scanning electron microscope, and the formation of needle-shaped crystals 203 was confirmed.
  • the film thickness was 850 ⁇ m
  • the column diameter of the needle-shaped crystal 203 was about 2.5 ⁇ m on the film surface side and about 0.3 ⁇ m on the substrate 101 side.
  • the weight of the scintillator 105 was weighed with an electronic balance, and the filling factor was calculated from the volume of the scintillator 105 using the above-mentioned calculation formula (1), and it was 73.3%. This filling factor was set to 100, and relative comparison was made with the examples described later.
  • the film surface of the scintillator 105 was brought into close contact with a CMOS photodetector via a Fiber Optical Plate (FOP), and an image was acquired by irradiating the substrate 101 with X-rays according to the international standard quality RQA5.
  • a value (MTF (2)) whose spatial frequency corresponds to 2 line pairs (2 Lp / mm) per 1 mm is used as an edge method using a knife edge made of tungsten. Asked by.
  • the MTF value at this time was set to 100, and a relative comparison was made with the examples described later.
  • the detection quantum efficiency DQE (0) at a spatial frequency of 0 Lp / mm, which is an index of the detection sensitivity was calculated. The detection quantum efficiency at this time was set to 100 and compared with the examples described later.
  • a scintillator 105 having an acicular crystal structure using cesium iodide as a base material, copper as an additive element, and thallium as an activator is formed by using the film forming apparatus 310 shown in FIG.
  • a material supply source 301a filled with cesium iodide, a material supply source 301b filled with copper iodide as the material 302b, and a material supply source 301c filled with thallium iodide as the material 302c were prepared.
  • the material supply sources 301a to 301c and the substrate 101 were arranged in the chamber 304 of the film forming apparatus 310, respectively.
  • the material supply sources 301a to 301c are cylindrical containers made of tantalum.
  • As the substrate 101 a silicon substrate laminated with an aluminum reflective layer having a thickness of 100 nm and silicon oxide having a thickness of 50 nm was used.
  • the scintillator 105 After vacuum exhausting the inside of the chamber 304 to 0.01 Pa or less, a current was gradually passed through the material supply sources 301a to 301c to heat the chamber 304.
  • the scintillator 105 is formed by opening the shutter (not shown) provided between the substrate 101 and the material supply sources 301a and 301c while rotating the substrate 101. The membrane was started. Further, two minutes after the film formation of the scintillator 105 is started, the shutter 303 provided between the material supply source 301b filled with the material 302b heated to 530 ° C. and the substrate 101 is opened, and the scintillator 105 is opened.
  • the addition of copper iodide to the acicular crystals 103 of the above was started.
  • the temperature of the substrate 101 was gradually raised from 60 ° C. at the start of film formation to 100 ° C. at the end of film formation. While confirming the state of film formation of the scintillator 105, each shutter was closed when the desired film thickness was formed, and the film formation was completed. After the film formation was completed, the temperature of the substrate 101 was further raised to 160 ° C.
  • FIGS. 5A and 5B After cooling the substrate 101 and the material supply sources 301a to 301c to room temperature, when the substrate 101 on which the scintillator 105 is formed is taken out and observed with a scanning electron microscope, needle-shaped crystals 103 are formed as shown in FIGS. 5A and 5B. Was confirmed.
  • the film thickness was 850 ⁇ m
  • the column diameter of the needle-shaped crystal 103 was 3.0 ⁇ m on the film surface side and about 0.6 ⁇ m on the substrate 101 side.
  • the relationship between the film thickness and the column diameter is shown in FIG. 8 above.
  • the chemical composition of the scintillator 105 was measured with a fluorescent X-ray analyzer, 0.4 mol% of thallium and 1.2 mol% of copper were detected on the film surface side with respect to the base material.
  • the weight of the scintillator 105 was weighed with an electronic balance and the filling rate was calculated from the volume of the scintillator 105 using the above-mentioned calculation formula (1), it was 78.5%, which was 107 when compared with the comparative example. That is, it was possible to realize the scintillator 105 having a filling rate of 75% or more while providing voids between the needle-shaped crystals 103.
  • the particle size of the initial growth portion 102 of the needle-shaped crystal 103 is the same as that in the case where copper is not added. That is, the column diameter of the initial growth portion 102 rapidly increases as shown in FIGS. 1 and 7 without reducing the size of the initial crystal as in the case of adding copper.
  • the crystal in the formation of the scintillator 105 having the needle-shaped crystal 103, the crystal is grown without adding copper to the initial growth portion 102, and then the needle is added while suppressing the increase in the column diameter by adding copper.
  • the crystalline part 104 was grown.
  • the filling rate of the scintillator 105 could be improved as compared with the comparative example in which copper was added from the initial stage of film formation. It was also found that it is possible to improve the detection quantum efficiency while maintaining the resolution.
  • a scintillator 105 having an acicular crystal structure using cesium iodide as a base material, copper as an additive element, and thallium as an activator is formed by using the film forming apparatus 310 shown in FIG.
  • a material supply source 301a filled with cesium iodide, a material supply source 301b filled with copper iodide as the material 302b, and a material supply source 301c filled with thallium iodide as the material 302c were prepared.
  • the material supply sources 301a to 301c and the substrate 101 were arranged in the chamber 304 of the film forming apparatus 310, respectively.
  • the material supply sources 301a to 301c are cylindrical containers made of tantalum.
  • As the substrate 101 a silicon substrate laminated with an aluminum reflective layer having a thickness of 100 nm and silicon oxide having a thickness of 50 nm was used.
  • the scintillator 105 After vacuum exhausting the inside of the chamber 304 to 0.01 Pa or less, a current was gradually passed through the material supply sources 301a to 301c to heat the chamber 304.
  • the scintillator 105 is formed by opening the shutter (not shown) provided between the substrate 101 and the material supply sources 301a and 301c while rotating the substrate 101. The membrane was started. Further, two minutes after the film formation of the scintillator 105 is started, the shutter 303 provided between the material supply source 301b filled with the material 302b heated to 540 ° C. and the substrate 101 is opened, and the scintillator 105 is opened.
  • the addition of copper iodide to the acicular crystals 103 of the above was started.
  • the temperature of the substrate 101 was gradually raised from 50 ° C. at the start of film formation to 100 ° C. at the end of film formation. While confirming the state of film formation of the scintillator 105, each shutter was closed when the desired film thickness was formed, and the film formation was completed. After the film formation was completed, the temperature of the substrate 101 was further raised to 160 ° C.
  • the substrate 101 on which the scintillator 105 was formed was taken out and observed with a scanning electron microscope, and the formation of needle-shaped crystal groups was confirmed.
  • the film thickness was 850 ⁇ m
  • the column diameter of the needle-shaped crystal was 1.2 ⁇ m on the film surface side, and about 0.5 ⁇ m on the substrate 101 side.
  • the chemical composition of the scintillator 105 was measured with a fluorescent X-ray analyzer, 0.8 mol% of thallium and 1.1 mol% of copper were detected on the film surface side with respect to the base material.
  • the initial growth portion 102 does not contain copper for the same reason as in Example 1 described above.
  • the weight of the scintillator 105 was weighed with an electronic balance and the filling rate was calculated from the volume of the scintillator 105 using the above-mentioned calculation formula (1), it was 77.3%, which was 103 when compared with the comparative example.
  • the scintillator 105 having a filling rate of 75% or more could be realized while providing voids between the needle-shaped crystals 103.
  • the crystals are grown without adding copper to the initial growth portion 102, and then the increase in the column diameter is suppressed by adding copper.
  • the needle-shaped crystal portion 104 was grown.
  • the filling rate of the scintillator 105 could be improved as compared with the comparative example in which copper was added from the initial stage of film formation.
  • the resolution and the detection quantum efficiency could be improved as compared with the comparative example.
  • FIGS. 9A and 9B are diagrams showing a configuration example of a radiation detection device 900 using the scintillator plate 100 of the present embodiment.
  • the radiation detector 900 includes a scintillator plate 100 and a sensor panel 901 for receiving light emitted from the scintillator 105.
  • the scintillator plate 100 may be attached to a sensor panel 901 in which a photoelectric conversion element for detecting light converted from radiation by the scintillator 105 is arranged.
  • a reflective layer may be formed on the substrate 101.
  • the radiation 902 can be applied to the radiation detection device 900 from the side of the substrate 101.
  • the scintillator 105 may be formed on the sensor panel 901 with the sensor panel 901 as a substrate.
  • the needle-shaped crystal 103 is formed on the main surface of the sensor panel on which the photoelectric conversion element is formed, in the order of the initial growth portion 102 and the needle-shaped crystal portion 104 from the side of the main surface.
  • a reflecting portion 903 for reflecting light may be arranged on the needle-shaped crystal portion 104 of the scintillator 105.
  • the radiation 902 can be applied to the radiation detection device 900 from the side of the reflection unit 903.
  • the X-ray 6060 generated in the X-ray tube 6050 which is a radiation source for irradiating the radiation image pickup device 6040 (corresponding to the above-mentioned radiation detection device 900), passes through the chest 6062 of the patient or the subject 6061 and emits radiation. It is incident on the image pickup apparatus 6040. This incident X-ray contains information about the inside of the body of the patient or subject 6061.
  • the scintillator 105 emits light in response to the incident of the X-ray 6060, which is photoelectrically converted by the photoelectric conversion element to obtain electrical information.
  • This information is converted to digital and image-processed by the image processor 6070 as a signal processing unit, and can be observed on the display 6080 as a display unit of the control room.
  • this information can be transferred to a remote location by a transmission processing unit such as a telephone line 6090.
  • a transmission processing unit such as a telephone line 6090.
  • a display 6081 which is a display unit such as a doctor's room in another place, and a doctor at a remote place can make a diagnosis.
  • this information can be recorded on a recording medium such as an optical disk, and can also be recorded on a film 6110 as a recording medium by the film processor 6100.

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Medical Informatics (AREA)
  • Optics & Photonics (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biophysics (AREA)
  • General Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • General Engineering & Computer Science (AREA)
  • Pathology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Biomedical Technology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Measurement Of Radiation (AREA)
  • Conversion Of X-Rays Into Visible Images (AREA)
  • Apparatus For Radiation Diagnosis (AREA)

Abstract

La présente invention concerne une plaque de scintillateur qui comporte un scintillateur disposé sur la surface principale d'une plaque de base. Le scintillateur comprend une pluralité de cristaux d'aiguille contenant un composé d'halogénure alcalin en tant que matériau hôte. Chaque cristal de la pluralité de cristaux d'aiguille comprend une partie de cristaux d'aiguille dans laquelle du cuivre a été ajouté, et une partie de croissance initiale disposée entre la surface principale et la partie de cristaux d'aiguille, la quantité de cuivre ajoutée étant inférieure à la quantité de cuivre dans la partie de cristaux d'aiguille.
PCT/JP2021/019559 2020-06-19 2021-05-24 Plaque de scintillateur, dispositif de détection de rayonnement, système de détection de rayonnement et procédé de fabrication de plaque de scintillateur WO2021256179A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2020-106405 2020-06-19
JP2020106405A JP2022001837A (ja) 2020-06-19 2020-06-19 シンチレータプレート、放射線検出装置、放射線検出システム、および、シンチレータプレートの製造方法

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WO2021256179A1 true WO2021256179A1 (fr) 2021-12-23

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004286601A (ja) * 2003-03-24 2004-10-14 Konica Minolta Holdings Inc 放射線画像変換パネルの製造方法及び放射線画像変換パネル
JP2007212218A (ja) * 2006-02-08 2007-08-23 Konica Minolta Medical & Graphic Inc シンチレータプレート
WO2008126740A1 (fr) * 2007-04-06 2008-10-23 Konica Minolta Medical & Graphic, Inc. Panneau de conversion d'image par rayonnement
US20120313013A1 (en) * 2011-06-10 2012-12-13 Manfred Fuchs Scintillator plate
JP2019090000A (ja) * 2017-11-10 2019-06-13 キヤノン株式会社 シンチレータ、その形成方法および放射線検出装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004286601A (ja) * 2003-03-24 2004-10-14 Konica Minolta Holdings Inc 放射線画像変換パネルの製造方法及び放射線画像変換パネル
JP2007212218A (ja) * 2006-02-08 2007-08-23 Konica Minolta Medical & Graphic Inc シンチレータプレート
WO2008126740A1 (fr) * 2007-04-06 2008-10-23 Konica Minolta Medical & Graphic, Inc. Panneau de conversion d'image par rayonnement
US20120313013A1 (en) * 2011-06-10 2012-12-13 Manfred Fuchs Scintillator plate
JP2019090000A (ja) * 2017-11-10 2019-06-13 キヤノン株式会社 シンチレータ、その形成方法および放射線検出装置

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