WO2016009815A1 - Radiation detector and scintillator panel - Google Patents

Radiation detector and scintillator panel Download PDF

Info

Publication number
WO2016009815A1
WO2016009815A1 PCT/JP2015/068568 JP2015068568W WO2016009815A1 WO 2016009815 A1 WO2016009815 A1 WO 2016009815A1 JP 2015068568 W JP2015068568 W JP 2015068568W WO 2016009815 A1 WO2016009815 A1 WO 2016009815A1
Authority
WO
WIPO (PCT)
Prior art keywords
phosphor layer
csi
peak
light
radiation
Prior art date
Application number
PCT/JP2015/068568
Other languages
French (fr)
Japanese (ja)
Inventor
篤也 吉田
弘 堀内
Original Assignee
株式会社 東芝
東芝電子管デバイス株式会社
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 株式会社 東芝, 東芝電子管デバイス株式会社 filed Critical 株式会社 東芝
Priority to CN201580038121.8A priority Critical patent/CN106796299B/en
Priority to KR1020167036684A priority patent/KR101903268B1/en
Publication of WO2016009815A1 publication Critical patent/WO2016009815A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
    • 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

  • Embodiments of the present invention relate to radiation detectors and scintillator panels.
  • the CsI / Tl phosphor layer can be easily formed into a flat film by vacuum evaporation. Moreover, by properly adjusting the film forming conditions, it is possible to form a film in which fiber crystals with a diameter of about 5 ⁇ m are arranged.
  • the fluorescence converted from X-rays in one fiber crystal reaches the light receiving element of the flat panel detector at a position not significantly shifted in the surface direction from the light emitting point. Thereby, a radiographed image which is not so blurred as an X-ray imaging apparatus can be obtained.
  • the light emitted from the CsI / Tl phosphor layer is incident on the CCD through a lens in a CCD-DR device, which is one form of an X-ray detector, for example, and is converted into an electrical signal by the CCD. By drawing the electrical signal on a monitor or using it for an image processing signal, a valid diagnostic image can be obtained.
  • a flat detector in which a CsI / Tl phosphor layer is formed on a photoelectric conversion substrate in which a plurality of light receiving elements are two-dimensionally arranged. In this case, since the CsI / Tl phosphor layer is formed on a photoelectric conversion substrate in which a plurality of light receiving elements are arranged via an organic film or the like, light emission can be more efficiently collected to the light receiving elements.
  • the requirement of the CsI / Tl phosphor layer is first required to be high in luminescence amount, that is, high in sensitivity. Besides, the resolution characteristics as a result of exhibiting the fiber plate function are important.
  • the CsI / Tl phosphor layer Strategies such as thickening the thickness of the pillar crystal, which is an element of the fiber structure, are in a trade-off relationship with other factors.
  • the film thickness of the CsI / Tl phosphor layer increases the amount of CsI / Tl phosphor material used and increases the cost. Furthermore, since the distance from the light emitting point converted from X-rays to light in the CsI / Tl phosphor layer to the light receiving element of the CCD-DR device or the flat panel detector becomes long, the light emitting point is isotropic in all directions. The distance by which the light emission having the property of diverging spreads in the surface direction of the light receiving element before reaching the light receiving element is also relatively long, and as a result, the resolution characteristic is degraded.
  • Making the pillar crystal thicker is equivalent to increasing the fiber diameter of the fiber plate, which also causes a decrease in resolution characteristics.
  • the sensitivity deterioration due to X-rays referred to here means that X-rays damage the CsI / Tl crystal lattice when X-rays are irradiated to each device after attaching a CsI / Tl phosphor layer to a CCD-DR or flat panel detector. It points to the phenomenon that the scratch becomes a light absorption site as a color center, and the emitted photon from the phosphor is reabsorbed in the CsI / Tl phosphor layer, and the amount of light output is reduced.
  • this phenomenon is that the defect of the crystal lattice is the emission mechanism of the CsI / Tl phosphor layer, such as exciton formation, energy transfer from the exciton to the Tl emission center, and emission transition mechanism formation from the Tl emission center. It is also possible that the state considered to be related to the state of the crystal lattice is deteriorated and the light emission efficiency is lowered.
  • the CsI / Tl phosphor layer has increased light absorption in the CsI / Tl phosphor layer due to sensitivity degradation due to X-rays, it is not uniform with respect to wavelength, and 440, 520, 560 nm There is an absorption peak in the vicinity.
  • the emission spectrum of the CsI / Tl phosphor layer has a peak at 510 to 560 nm. Therefore, the emission spectrum of the CsI / Tl phosphor layer matches the absorption peaks at 520 and 560 nm, and the sensitivity characteristic of the CsI / Tl phosphor layer is degraded.
  • the problem to be solved by the present invention is to provide a radiation detector and a scintillator panel capable of improving the sensitivity of the phosphor layer and reducing the decrease in the sensitivity of the phosphor layer due to radiation.
  • a radiation detector includes a photoelectric conversion substrate in which a plurality of light receiving elements are arrayed, and a phosphor layer formed on the photoelectric conversion substrate and converting radiation into light.
  • the emission spectrum of the phosphor layer has a main peak in the wavelength region of 510 to 550 nm and a side peak in the longer wavelength region than this main peak.
  • the scintillator panel includes a substrate that transmits radiation, and a phosphor layer that is formed on the substrate and that converts the radiation into light.
  • the emission spectrum in which the phosphor layer converts radiation into light has a main peak in a wavelength range of 510 to 550 nm and a side peak in a longer wavelength range than the main peak.
  • FIG. 1 is an exploded perspective view showing a part of the radiation detector according to the first embodiment.
  • FIG. 2 is a schematic cross-sectional view of the radiation detector.
  • FIG. 3 is a graph showing the relationship between the wavelength of the emission spectrum of the phosphor layer of the radiation detector and the emission intensity.
  • FIG. 4 is a graph showing the relationship between the wavelength and the emission intensity obtained by analyzing the emission spectrum of the phosphor layer with a Gaussian function.
  • FIG. 5 is a table showing sensitivities before and after X-ray irradiation of a plurality of samples in the phosphor layer.
  • FIG. 6 is a graph showing the relationship between the wavelength of the light absorption spectrum of the phosphor layer and the light absorptivity.
  • FIG. 7 is a schematic cross-sectional view showing a radiation detector according to the second embodiment.
  • FIG. 8 is a schematic cross-sectional view showing a radiation detector according to the third embodiment.
  • FIG. 2 is a schematic cross-sectional view of a radiation detector.
  • the radiation detector 1 is, for example, a large-sized flat X-ray detector.
  • the radiation detector 1 has an X-ray detection panel 3 for detecting X-rays 2 as radiation.
  • the X-ray detection panel 3 is supported on one surface of the support substrate 4.
  • the X-ray incident surface side of the X-ray detection panel 3 is covered with a moisture-proof cover 5.
  • the circuit board 8 for driving the X-ray detection panel 3 is disposed on the other surface of the support substrate 4 via the lead plate 6 and the heat radiation insulation sheet 7.
  • the circuit board 8 and the X-ray detection panel 3 are connected by a flexible circuit board 9.
  • the support substrate 4 is fixed to the inside of the housing 11 via the support 10.
  • an incident window 12 to which the X-ray 2 is incident is provided on the X-ray incident surface side of the housing 11.
  • FIG. 1 is an exploded perspective view of a part of the radiation detector 1.
  • the X-ray detection panel 3 has a photoelectric conversion substrate 21 and a CsI / Tl phosphor layer 22 which is a scintillator layer and is a phosphor layer.
  • the photoelectric conversion substrate 21 is provided with a 0.7 mm thick glass substrate and a plurality of light detection portions 25 two-dimensionally formed on the glass substrate.
  • the light detection unit 25 includes a TFT (thin film transistor) 26 as a switching element and a photodiode 27 as a photo sensor as a light receiving element.
  • the TFT 26 and the photodiode 27 are formed using, for example, a-Si (amorphous silicon) as a base material.
  • the size in the direction along the plane of the photoelectric conversion substrate 21 is, for example, a square, and one side is 50 cm.
  • the CsI / Tl phosphor layer 22 is directly formed on the photoelectric conversion substrate 21.
  • the CsI / Tl phosphor layer 22 is located on the X-ray incident side of the photoelectric conversion substrate 21.
  • the CsI / Tl phosphor layer 22 converts X-rays 2 into light (fluorescent light).
  • the photodiode 27 converts the light converted by the CsI / Tl phosphor layer 22 into an electrical signal.
  • the CsI / Tl phosphor layer 22 is formed by depositing a scintillator material on the photoelectric conversion substrate 21.
  • a scintillator material a material containing cesium iodide (CsI) as a main component can be used.
  • the thickness of the CsI / Tl phosphor layer 22 is set in the range of 100 to 1000 ⁇ m. More suitably, the thickness of the CsI / Tl phosphor layer 22 is set in the range of 200 to 600 ⁇ m in order to evaluate the sensitivity and the resolution. In the present embodiment, the thickness of the CsI / Tl phosphor layer 22 is adjusted to 500 ⁇ m.
  • a scintillator material a material in which thallium (Tl) or thallium iodide (TlI) is added to CsI which is a main component is used.
  • the CsI / Tl phosphor layer 22 can emit light (fluorescent light) of an appropriate wavelength when the X-ray 2 is incident.
  • the moisture-proof cover 5 shown in FIG. 2 completely covers the CsI / Tl phosphor layer 22 and is sealed to the CsI / Tl phosphor layer 22.
  • the moistureproof cover 5 is made of, for example, an aluminum alloy.
  • the thickness of the moisture-proof cover 5 is increased, the X-ray dose incident on the CsI / Tl phosphor layer 22 is attenuated, and the sensitivity of the X-ray detection panel 3 is lowered. Therefore, it is desirable that the thickness of the moistureproof cover 5 be as small as possible.
  • the thickness of the moisture-proof cover 5 In setting the thickness of the moisture-proof cover 5, the balance of various parameters such as stability of shape of the moisture-proof cover 5, strength to withstand manufacture, attenuation of X-ray 2 incident on the CsI / Tl phosphor layer 22 is taken into consideration Be done. As a result of consideration, the thickness of the moistureproof cover 5 is set in the range of 50 to 500 ⁇ m. In the present embodiment, the thickness of the moisture-proof cover 5 is set to 200 ⁇ m.
  • a plurality of pads for connecting to the outside are formed on the outer peripheral portion of the photoelectric conversion substrate 21, a plurality of pads for connecting to the outside are formed.
  • the plurality of pads are used as an input of an electrical signal for driving the photoelectric conversion substrate 21 and an output of an output signal.
  • the assembly of the X-ray detection panel 3 and the moisture-proof cover 5 is configured by laminating thin members, the assembly is light and has low strength. For this reason, the X-ray detection panel 3 is fixed to one flat surface of the support substrate 4 via the adhesive sheet.
  • the support substrate 4 is made of, for example, an aluminum alloy, and has the strength necessary to support and hold the X-ray detection panel 3.
  • the circuit board 8 is fixed to the other surface of the support substrate 4 via the lead plate 6 and the heat radiation insulation sheet 7.
  • the circuit board 8 and the X-ray detection panel 3 are connected via the flexible circuit board 9.
  • a thermocompression bonding method using an ACF (anisotropic conductive film) is used to connect the flexible circuit substrate 9 and the photoelectric conversion substrate 21. By this method, electrical connection of a plurality of fine signal lines is secured.
  • a connector corresponding to the flexible circuit board 9 is mounted on the circuit board 8.
  • the circuit board 8 is electrically connected to the X-ray detection panel 3 via a connector or the like.
  • the circuit board 8 electrically drives the X-ray detection panel 3 and electrically processes an output signal from the X-ray detection panel 3.
  • the housing 11 accommodates the X-ray detection panel 3, the support substrate 4, the moisture-proof cover 5, the circuit substrate 8, the lead plate 6, the heat radiation insulation sheet 7, and the support 10.
  • the housing 11 has an opening formed at a position facing the X-ray detection panel 3.
  • the support 10 is fixed to the housing 11 and supports the support substrate 4.
  • the entrance window 12 is attached to the opening of the housing 11. Since the entrance window 12 transmits the X-rays 2, the X-rays 2 pass through the entrance window 12 and are incident on the X-ray detection panel 3.
  • the entrance window 12 is formed in a plate shape and has a function of protecting the inside of the housing 11.
  • the entrance window 12 is desirably thinly formed of a material having a low X-ray absorptivity. Thereby, the scattering of the X-rays 2 and the attenuation of the X-ray generated at the entrance window 12 can be reduced.
  • FIG. 3 is a graph showing the relationship between the wavelength of the emission spectrum of the CsI / Tl phosphor layer 22 and the emission intensity.
  • the emission spectrum is normalized so that the integral value or the area with respect to the wavelength becomes the same.
  • the samples include Examples 1 and 2 corresponding to the present embodiment and Comparative Examples 1 to 4.
  • the emission spectrum of Example 1 has a main peak at 530 nm, and another peak, ie, a secondary peak, is buried at 560 to 600 nm.
  • the standard deviation of the Gaussian function of the main peak of 530 nm is 25 nm, and the standard deviation of the Gaussian function of the minor peak of 580 nm is 30 nm.
  • P in FIG. 4 is a calculated value of the emission spectrum of Example 1 based on the Gaussian function.
  • the properties of the CsI / Tl phosphor layer 22 of Examples 1 and 2 can be adjusted by the process in the manufacturing process of the CsI / Tl phosphor layer 22, and in particular by manipulating the effect of strain during crystallization of Tl. It is possible to adjust.
  • Comparative Examples 1 to 4 have a main peak of 520 to 545 nm, but Comparative Examples 2 and 3 have no side peak, and Comparative Examples 1 and 4 have a side peak on the shorter wavelength side than the main peak.
  • the main peak is 530 to 545 nm, which is comparable to that of Comparative Examples 1 to 4, but the side peak is 580 longer than the main peak. Since it is in the range of 595 nm, it is easy to obtain high sensitivity characteristics with good matching with the sensor sensitivity used in the flat panel detector and the CCD-DR apparatus.
  • the CsI / Tl phosphor layer 22 of Examples 1 and 2 has a sensitivity peak (550 nm) of amorphous silicon used in a flat panel detector and a sensitivity peak (550 nm) of CCD used in a CCD-DR apparatus, that is, crystalline silicon. It is consistent with the longer wavelength side) and it is easy to obtain high sensitivity characteristics as an apparatus.
  • the CsI / Tl phosphor layers 22 of Examples 1 and 2 have sensitivity residual rates after irradiation with X-rays of 11500 R, which are equivalent to Comparative Example 1 and superior to Comparative Examples 2 to 4.
  • Comparative Example 1 is inferior to the CsI / Tl phosphor layer 22 of Examples 1 and 2 in sensitivity characteristics.
  • Example 6 is a graph showing the relationship between the wavelength of the light absorption spectrum of the CsI / Tl phosphor layer 22 of Example 1 and Comparative Example 4 and the light absorptivity.
  • the vertical axis is a numerical value corresponding to the light absorptivity, it was not possible to evaluate the contribution of the light which disappears due to scattering in measurement, so the correct light absorptivity is not calculated, and it is an arbitrary unit .
  • Example 1 In both the samples of Example 1 and Comparative Example 4, the transmittance increases as the wavelength after X-ray irradiation (after 1000 hours) becomes longer than before X-ray irradiation, and the peak of light absorption at 520 nm and 560 nm Was present. And it was confirmed that the size of the peak increases by continuing X-ray irradiation.
  • the emission spectrum of CsI / Tl phosphor layer 22 has an X-ray resistance that is different from 520 to 560 nm, at which the light absorptance increases. It proved to be an effective means to improve.
  • the emission spectrum of the CsI / Tl phosphor layer 22 has a main peak of 510 to 550 nm and an auxiliary peak in a longer wavelength region than the main peak, whereby the sensitivity of the CsI / Tl phosphor layer 22 is obtained. While reducing the sensitivity of the CsI / Tl phosphor layer 22 due to radiation.
  • the side peak is in the wavelength region of 560 to 600 nm, the sensitivity of the CsI / Tl phosphor layer 22 can be improved, and the decrease in sensitivity of the CsI / Tl phosphor layer 22 due to radiation can be reduced.
  • the range of the secondary peak is influenced by the light absorption peak when the wavelength is shorter than 560 nm, and when it is longer than 600 nm, the sensitivity peak and the difference between the sensitivity peaks of amorphous silicon used in the flat panel detector become large. Therefore, a wavelength range of 560 to 600 nm is preferable.
  • FIG. 7 shows a second embodiment.
  • the same reference numerals are used for the same configuration as the first embodiment, and the description of the configuration and the effects is omitted.
  • FIG. 7 shows a scintillator panel 31 and a radiation detector 32 which is a flat panel detector using the scintillator panel 31.
  • a CsI / Tl phosphor layer 22 is formed on a substrate 33 that transmits X-rays via a reflective layer 34.
  • the reflective layer 34 is interposed between the substrate 33 and the CsI / Tl phosphor layer 22.
  • the CsI / Tl phosphor layer 22 is covered by a moisture-proof film 35.
  • a radiation detector 32 is configured by combining the scintillator panel 31 and the photoelectric conversion substrate 36.
  • the photoelectric conversion substrate 36 includes a photodiode 37 as a light receiving element, and is configured in the same manner as the photoelectric conversion substrate 21 of the first embodiment.
  • FIG. 8 shows a third embodiment.
  • the same reference numerals are used for the same configurations as the first and second embodiments, and the descriptions of the configurations and the effects are omitted.
  • FIG. 8 shows a CCD-DR device 41 as a radiation detector using the scintillator panel 31.
  • the CCD-DR device 41 has a housing 42, the scintillator panel 31 is disposed at one end of the housing 42, a mirror reflector 43 and a lens 44 are provided inside the housing 42, and the housing 42 is A light receiving element (CCD) 45 is installed at the other end.
  • CCD light receiving element
  • the X-ray 2 emitted from the X-ray source enters the scintillator panel 31 and the light 46 converted by the CsI / Tl phosphor layer 22 is emitted from the surface of the CsI / Tl phosphor layer 22 Be done.
  • An X-ray image is projected on the surface of the CsI / Tl phosphor layer 22, and this X-ray image is reflected by the reflection plate 43 and collected by the lens 44 and irradiated onto the light receiving element 45. Converts an image into an electrical signal and outputs it.

Landscapes

  • Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Molecular Biology (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Measurement Of Radiation (AREA)
  • Conversion Of X-Rays Into Visible Images (AREA)
  • Luminescent Compositions (AREA)

Abstract

A radiation detector (1) is provided with: a photoelectric conversion substrate (21) having a plurality of light receiving elements disposed thereon; and a phosphor layer, which is formed on the photoelectric conversion substrate, and which converts radiation into light. Emission spectrum of the phosphor layer has a main peak in a wavelength region having a wavelength of 510-550 nm, and a sub-peak in a wavelength region having a wavelength longer than that of the wavelength region having the main peak.

Description

放射線検出器およびシンチレータパネルRadiation detector and scintillator panel
　本発明の実施形態は、放射線検出器およびシンチレータパネルに関する。 Embodiments of the present invention relate to radiation detectors and scintillator panels.
　従来、医療用、歯科用もしくは非破壊検査用など、昨今のデジタル化したＸ線検出器は、入射Ｘ線を蛍光体層で一旦光（蛍光）に変換する方式が主流である。蛍光体層としていくつかの種類の材料が用いられているが、医療用の平面検出器や、歯科用のＣＭＯＳセンサーや、医療用・動物診断用であるＣＣＤ－ＤＲ装置には、タリウム賦活ヨウ化セシウム（以下、ＣｓＩ／Ｔｌと称する）が多く使用されている。 2. Description of the Related Art In the past, the mainstream of recent digitalized X-ray detectors such as for medical use, dental use or nondestructive inspection is a method of temporarily converting incident X-rays into light (fluorescent light) by a phosphor layer. Although several types of materials are used as phosphor layers, thallium-activated iodine is used in flat detectors for medical use, CMOS sensors for dental use, and CCD-DR devices for medical and animal diagnosis. Cesium (hereinafter referred to as CsI / Tl) is widely used.
　ＣｓＩ／Ｔｌ蛍光体層は、真空蒸着法で簡便に平面状に成膜できる。しかも、成膜条件を適正に調整することにより、直径５μｍ程度のファイバー結晶が並んだ構造に成膜することができる。ファイバー結晶構造にすることにより、ＣｓＩ結晶（屈折率＝１．８）と結晶間の隙間（屈折率＝１）との間に屈折率の差が生じる。ある１つのファイバー結晶中でＸ線から変換された蛍光は、発光点から面方向にそれほどずれない位置で平面検出器の受光素子に到達する。これにより、Ｘ線撮像装置としてそれほど滲まない撮影像が得られる。 The CsI / Tl phosphor layer can be easily formed into a flat film by vacuum evaporation. Moreover, by properly adjusting the film forming conditions, it is possible to form a film in which fiber crystals with a diameter of about 5 μm are arranged. The fiber crystal structure causes a difference in refractive index between the CsI crystal (refractive index = 1.8) and the gap between the crystals (refractive index = 1). The fluorescence converted from X-rays in one fiber crystal reaches the light receiving element of the flat panel detector at a position not significantly shifted in the surface direction from the light emitting point. Thereby, a radiographed image which is not so blurred as an X-ray imaging apparatus can be obtained.
　つまり、ＣｓＩ／Ｔｌ蛍光体層は適正な条件で成膜することにより、Ｘ線を光に変換するシンチレーション機能と、画像を受光素子まで画像を保持するファイバープレート機能とを同時に備えることが可能である。 That is, by forming a CsI / Tl phosphor layer under appropriate conditions, it is possible to simultaneously provide a scintillation function for converting X-rays into light and a fiber plate function for holding an image up to the light receiving element. is there.
　ＣｓＩ／Ｔｌ蛍光体層からの発光は、例えばＸ線検出器の１つの形態であるＣＣＤ－ＤＲ装置において、レンズを介してＣＣＤに入射し、ＣＣＤにて電気信号に変換される。上記電気信号をモニターに描出したり、画像処理信号に使用したりすることで、有効な診断画像が得られる。これは、複数の受光素子が二次元に配列された光電変換基板上にＣｓＩ／Ｔｌ蛍光体層が成膜された平面検出器の場合も同様である。この場合は、有機膜などを介してＣｓＩ／Ｔｌ蛍光体層を複数の受光素子が配列した光電変換基板上に成膜するので、より効率的に発光を受光素子に収集することができる。 The light emitted from the CsI / Tl phosphor layer is incident on the CCD through a lens in a CCD-DR device, which is one form of an X-ray detector, for example, and is converted into an electrical signal by the CCD. By drawing the electrical signal on a monitor or using it for an image processing signal, a valid diagnostic image can be obtained. The same applies to a flat detector in which a CsI / Tl phosphor layer is formed on a photoelectric conversion substrate in which a plurality of light receiving elements are two-dimensionally arranged. In this case, since the CsI / Tl phosphor layer is formed on a photoelectric conversion substrate in which a plurality of light receiving elements are arranged via an organic film or the like, light emission can be more efficiently collected to the light receiving elements.
　上記の過程を考えると、ＣｓＩ／Ｔｌ蛍光体層に必要な要件として、まず、発光量の多さ、すなわち感度が高いことが求められる。他には、ファイバープレート機能を発揮させた結果としての解像度特性が重要である。 Considering the above process, the requirement of the CsI / Tl phosphor layer is first required to be high in luminescence amount, that is, high in sensitivity. Besides, the resolution characteristics as a result of exhibiting the fiber plate function are important.
　ＣｓＩ／Ｔｌ蛍光体層の感度に関しては、ＣｓＩ／Ｔｌ蛍光体層の膜厚を厚くすること、Ｔｌ濃度を適正化すること、ＣｓＩ／Ｔｌ膜のファイバー構造の要素であるピラー結晶の太さを太くすること、などが挙げられる。 Regarding the sensitivity of the CsI / Tl phosphor layer, increasing the film thickness of the CsI / Tl phosphor layer, optimizing the Tl concentration, and the thickness of the pillar crystal that is an element of the fiber structure of the CsI / Tl film Thickening, etc. may be mentioned.
　しかしながら、ＣｓＩ／Ｔｌ蛍光体層の感度を向上させるのに、ＣｓＩ／Ｔｌ蛍光体層単独の性能向上を狙って、ＣｓＩ／Ｔｌ蛍光体層の膜厚を厚くすること、ＣｓＩ／Ｔｌ蛍光体層のファイバー構造の要素であるピラー結晶の太さを太くすること、などの方策は、他の要因とトレードオフの関係にある。 However, in order to improve the sensitivity of the CsI / Tl phosphor layer, increasing the film thickness of the CsI / Tl phosphor layer aiming to improve the performance of the CsI / Tl phosphor layer alone, the CsI / Tl phosphor layer Strategies such as thickening the thickness of the pillar crystal, which is an element of the fiber structure, are in a trade-off relationship with other factors.
　例えば、ＣｓＩ／Ｔｌ蛍光体層の膜厚を厚くすることは、ＣｓＩ／Ｔｌ蛍光体の材料の使用量が増大し、コストが上昇する。さらに、ＣｓＩ／Ｔｌ蛍光体層中でＸ線から光に変換される発光点と、ＣＣＤ－ＤＲ装置や平面検出器の受光素子までの距離が長くなるので、発光点から八方に等方的に発散する性質がある発光が、受光素子に到達するまでに受光素子の面方向に広がる距離も相対的に長くなり、結果として解像度特性が低下する。 For example, increasing the film thickness of the CsI / Tl phosphor layer increases the amount of CsI / Tl phosphor material used and increases the cost. Furthermore, since the distance from the light emitting point converted from X-rays to light in the CsI / Tl phosphor layer to the light receiving element of the CCD-DR device or the flat panel detector becomes long, the light emitting point is isotropic in all directions. The distance by which the light emission having the property of diverging spreads in the surface direction of the light receiving element before reaching the light receiving element is also relatively long, and as a result, the resolution characteristic is degraded.
　ピラー結晶を太くすることは、ファイバープレートのファイバー径を大きくすることと等価であり、これも解像度特性の低下を引き起こす。 Making the pillar crystal thicker is equivalent to increasing the fiber diameter of the fiber plate, which also causes a decrease in resolution characteristics.
　また、ＣｓＩ／Ｔｌ蛍光体層の感度特性を阻害する要因として、Ｘ線による感度劣化がある。ここでいうＸ線による感度劣化とは、ＣｓＩ／Ｔｌ蛍光体層をＣＣＤ－ＤＲや平面検出器に装着した後に、Ｘ線を各デバイスに照射すると、Ｘ線がＣｓＩ／Ｔｌ結晶格子に傷を与え、その傷が色中心として光吸収サイトとなり、蛍光体からの発光光子をＣｓＩ／Ｔｌ蛍光体層中で再吸収してしまい、出力される光の量が減少する現象を指す。 In addition, as a factor that obstructs the sensitivity characteristic of the CsI / Tl phosphor layer, there is sensitivity deterioration due to X-rays. The sensitivity deterioration due to X-rays referred to here means that X-rays damage the CsI / Tl crystal lattice when X-rays are irradiated to each device after attaching a CsI / Tl phosphor layer to a CCD-DR or flat panel detector. It points to the phenomenon that the scratch becomes a light absorption site as a color center, and the emitted photon from the phosphor is reabsorbed in the CsI / Tl phosphor layer, and the amount of light output is reduced.
　さらに、この現象は、結晶格子の傷がＣｓＩ／Ｔｌ蛍光体層の発光機構である、励起子形成、励起子からのＴｌ発光中心へのエネルギーの移送、Ｔｌ発光中心からの発光遷移機構形成といった、結晶格子の状態と関連があると考えられる状態を劣化させ、発光効率を低下させている可能性も考えられる。 Furthermore, this phenomenon is that the defect of the crystal lattice is the emission mechanism of the CsI / Tl phosphor layer, such as exciton formation, energy transfer from the exciton to the Tl emission center, and emission transition mechanism formation from the Tl emission center. It is also possible that the state considered to be related to the state of the crystal lattice is deteriorated and the light emission efficiency is lowered.
　このように、ＣｓＩ／Ｔｌ蛍光体層は、Ｘ線による感度劣化により、ＣｓＩ／Ｔｌ蛍光体層内での光吸収が増大するが、それは波長に対して一様ではなく、４４０、５２０、５６０ｎｍ近辺に吸収ピークがある。一方、ＣｓＩ／Ｔｌ蛍光体層の発光スペクトルは５１０～５６０ｎｍにピークを持つことが知られている。そのため、ＣｓＩ／Ｔｌ蛍光体層の発光スペクトルと５２０および５６０ｎｍの吸収ピークとが一致してしまい、ＣｓＩ／Ｔｌ蛍光体層の感度特性が低下する。 Thus, although the CsI / Tl phosphor layer has increased light absorption in the CsI / Tl phosphor layer due to sensitivity degradation due to X-rays, it is not uniform with respect to wavelength, and 440, 520, 560 nm There is an absorption peak in the vicinity. On the other hand, it is known that the emission spectrum of the CsI / Tl phosphor layer has a peak at 510 to 560 nm. Therefore, the emission spectrum of the CsI / Tl phosphor layer matches the absorption peaks at 520 and 560 nm, and the sensitivity characteristic of the CsI / Tl phosphor layer is degraded.
特許第４６５３４４２号公報Patent No. 4652442
　本発明が解決しようとする課題は、蛍光体層の感度を向上させるとともに、放射線による蛍光体層の感度低下を低減することができる放射線検出器およびシンチレータパネルを提供することである。 The problem to be solved by the present invention is to provide a radiation detector and a scintillator panel capable of improving the sensitivity of the phosphor layer and reducing the decrease in the sensitivity of the phosphor layer due to radiation.
　一実施形態に係る放射線検出器は、複数の受光素子が配列された光電変換基板と、光電変換基板上に形成され、放射線を光に変換する蛍光体層とを具備する。蛍光体層の発光スペクトルは、５１０～５５０ｎｍの波長領域に主ピークを有するとともに、この主ピークよりも長波長領域に副ピークを有する。 A radiation detector according to an embodiment includes a photoelectric conversion substrate in which a plurality of light receiving elements are arrayed, and a phosphor layer formed on the photoelectric conversion substrate and converting radiation into light. The emission spectrum of the phosphor layer has a main peak in the wavelength region of 510 to 550 nm and a side peak in the longer wavelength region than this main peak.
　また、一実施形態に係るシンチレータパネルは、放射線を透過する基板と、前記基板上に形成され、放射線を光に変換する蛍光体層と、を具備する。前記蛍光体層が放射線を光に変換する発光スペクトルは、５１０～５５０ｎｍの波長領域に主ピークを有するとともに、この主ピークよりも長波長領域に副ピークを有する。 The scintillator panel according to one embodiment includes a substrate that transmits radiation, and a phosphor layer that is formed on the substrate and that converts the radiation into light. The emission spectrum in which the phosphor layer converts radiation into light has a main peak in a wavelength range of 510 to 550 nm and a side peak in a longer wavelength range than the main peak.
図１は、第１の実施形態に係る放射線検出器の一部を示す分解斜視図である。FIG. 1 is an exploded perspective view showing a part of the radiation detector according to the first embodiment. 図２は、上記放射線検出器の概略断面図である。FIG. 2 is a schematic cross-sectional view of the radiation detector. 図３は、上記放射線検出器の蛍光体層の発光スペクトルの波長と発光強度との関係をグラフで示す図である。FIG. 3 is a graph showing the relationship between the wavelength of the emission spectrum of the phosphor layer of the radiation detector and the emission intensity. 図４は、上記蛍光体層の発光スペクトルをガウス関数で分析した波長と発光強度との関係をグラフで示す図である。FIG. 4 is a graph showing the relationship between the wavelength and the emission intensity obtained by analyzing the emission spectrum of the phosphor layer with a Gaussian function. 図５は、上記蛍光体層に複数のサンプルのＸ線照射前後の感度を表で示す図である。FIG. 5 is a table showing sensitivities before and after X-ray irradiation of a plurality of samples in the phosphor layer. 図６は、上記蛍光体層の光吸収スペクトルの波長と光吸収率との関係をグラフで示す図である。FIG. 6 is a graph showing the relationship between the wavelength of the light absorption spectrum of the phosphor layer and the light absorptivity. 図７は、第２の実施形態に係る放射線検出器を示す概略断面図である。FIG. 7 is a schematic cross-sectional view showing a radiation detector according to the second embodiment. 図８は、第３の実施形態に係る放射線検出器を示す概略断面図である。FIG. 8 is a schematic cross-sectional view showing a radiation detector according to the third embodiment.
　以下、第１の実施形態を、図１ないし図６を参照して説明する。 Hereinafter, a first embodiment will be described with reference to FIGS. 1 to 6.
　図２は放射線検出器の概略断面図である。 FIG. 2 is a schematic cross-sectional view of a radiation detector.
　図２に示すように、放射線検出器１は、例えば大型の平面Ｘ線検出装置である。 As shown in FIG. 2, the radiation detector 1 is, for example, a large-sized flat X-ray detector.
　放射線検出器１は、放射線としてのＸ線２を検出するＸ線検出パネル３を有している。Ｘ線検出パネル３は支持基板４の一面に支持されている。Ｘ線検出パネル３のＸ線入射面側は防湿カバー５で覆われている。 The radiation detector 1 has an X-ray detection panel 3 for detecting X-rays 2 as radiation. The X-ray detection panel 3 is supported on one surface of the support substrate 4. The X-ray incident surface side of the X-ray detection panel 3 is covered with a moisture-proof cover 5.
　支持基板４の他面には、鉛プレート６および放熱絶縁シート７を介して、Ｘ線検出パネル３を駆動する回路基板８が配設されている。この回路基板８とＸ線検出パネル３とはフレキシブル回路基板９で接続されている。 The circuit board 8 for driving the X-ray detection panel 3 is disposed on the other surface of the support substrate 4 via the lead plate 6 and the heat radiation insulation sheet 7. The circuit board 8 and the X-ray detection panel 3 are connected by a flexible circuit board 9.
　支持基板４は、支柱10を介して筐体11の内部に固定されている。筐体11のＸ線入射面側には、Ｘ線２が入射する入射窓12が設けられている。 The support substrate 4 is fixed to the inside of the housing 11 via the support 10. On the X-ray incident surface side of the housing 11, an incident window 12 to which the X-ray 2 is incident is provided.
　次に、図１は放射線検出器１の一部の分解斜視図である。 Next, FIG. 1 is an exploded perspective view of a part of the radiation detector 1.
　図１に示すように、Ｘ線検出パネル３は、光電変換基板21と、シンチレータ層であって蛍光体層としてのＣｓＩ／Ｔｌ蛍光体層22とを有している。 As shown in FIG. 1, the X-ray detection panel 3 has a photoelectric conversion substrate 21 and a CsI / Tl phosphor layer 22 which is a scintillator layer and is a phosphor layer.
　光電変換基板21は、０．７ｍｍ厚のガラス基板と、ガラス基板上に２次元的に形成された複数の光検出部25とを備えている。光検出部25は、スイッチング素子としてのＴＦＴ（薄膜トランジスタ）26および受光素子としてのフォトセンサであるフォトダイオード27を有している。ＴＦＴ26およびフォトダイオード27は、例えばａ－Ｓｉ（アモルファスシリコン）を基材として形成されている。光電変換基板21の平面に沿った方向のサイズは、例えば、正方形であり、１辺が５０ｃｍである。 The photoelectric conversion substrate 21 is provided with a 0.7 mm thick glass substrate and a plurality of light detection portions 25 two-dimensionally formed on the glass substrate. The light detection unit 25 includes a TFT (thin film transistor) 26 as a switching element and a photodiode 27 as a photo sensor as a light receiving element. The TFT 26 and the photodiode 27 are formed using, for example, a-Si (amorphous silicon) as a base material. The size in the direction along the plane of the photoelectric conversion substrate 21 is, for example, a square, and one side is 50 cm.
　ＣｓＩ／Ｔｌ蛍光体層22は、光電変換基板21上に直接形成されている。ＣｓＩ／Ｔｌ蛍光体層22は、光電変換基板21のＸ線２の入射側に位置している。ＣｓＩ／Ｔｌ蛍光体層22は、Ｘ線２を光（蛍光）に変換するものである。なお、フォトダイオード27は、ＣｓＩ／Ｔｌ蛍光体層22で変換された光を電気信号に変換するものである。 The CsI / Tl phosphor layer 22 is directly formed on the photoelectric conversion substrate 21. The CsI / Tl phosphor layer 22 is located on the X-ray incident side of the photoelectric conversion substrate 21. The CsI / Tl phosphor layer 22 converts X-rays 2 into light (fluorescent light). The photodiode 27 converts the light converted by the CsI / Tl phosphor layer 22 into an electrical signal.
　ＣｓＩ／Ｔｌ蛍光体層22は、光電変換基板21上にシンチレータ材を蒸着させることにより形成されている。シンチレータ材としては、ヨウ化セシウム（ＣｓＩ）を主成分とする材料を用いることができる。 The CsI / Tl phosphor layer 22 is formed by depositing a scintillator material on the photoelectric conversion substrate 21. As the scintillator material, a material containing cesium iodide (CsI) as a main component can be used.
　ＣｓＩ／Ｔｌ蛍光体層22の厚みは、１００乃至１０００μｍの範囲内に設定されている。より適切には、感度と解像度とを評価して、ＣｓＩ／Ｔｌ蛍光体層22の厚みは、２００乃至６００μｍの範囲内に設定されている。そして、本実施形態において、ＣｓＩ／Ｔｌ蛍光体層22の厚みは、５００μｍに調整されている。シンチレータ材としては、主成分であるＣｓＩにタリウム（Ｔｌ）またはヨウ化タリウム（ＴｌＩ）を添加した材料を用いている。これにより、ＣｓＩ／Ｔｌ蛍光体層22は、Ｘ線２が入射されることにより適切な波長の光（蛍光）を放出することができる。 The thickness of the CsI / Tl phosphor layer 22 is set in the range of 100 to 1000 μm. More suitably, the thickness of the CsI / Tl phosphor layer 22 is set in the range of 200 to 600 μm in order to evaluate the sensitivity and the resolution. In the present embodiment, the thickness of the CsI / Tl phosphor layer 22 is adjusted to 500 μm. As a scintillator material, a material in which thallium (Tl) or thallium iodide (TlI) is added to CsI which is a main component is used. Thus, the CsI / Tl phosphor layer 22 can emit light (fluorescent light) of an appropriate wavelength when the X-ray 2 is incident.
　なお、図２に示す防湿カバー５は、ＣｓＩ／Ｔｌ蛍光体層22を完全に覆い、ＣｓＩ／Ｔｌ蛍光体層22に封着されている。防湿カバー５は、例えばアルミニウム合金で形成されている。防湿カバー５の厚みが大きくなると、ＣｓＩ／Ｔｌ蛍光体層22に入射されるＸ線量が減衰し、Ｘ線検出パネル３の感度の低下を招いてしまう。このため、防湿カバー５の厚みは、なるべく小さくした方が望ましい。防湿カバー５の厚みを設定するにあたっては、防湿カバー５の形状の安定性、製造に耐える強度、ＣｓＩ／Ｔｌ蛍光体層22に入射されるＸ線２の減衰量などの各種パラメータのバランスが考慮される。考慮の結果、防湿カバー５の厚みは、５０乃至５００μｍの範囲内に設定されている。本実施形態において、防湿カバー５の厚みは、２００μｍに設定されている。 The moisture-proof cover 5 shown in FIG. 2 completely covers the CsI / Tl phosphor layer 22 and is sealed to the CsI / Tl phosphor layer 22. The moistureproof cover 5 is made of, for example, an aluminum alloy. When the thickness of the moisture-proof cover 5 is increased, the X-ray dose incident on the CsI / Tl phosphor layer 22 is attenuated, and the sensitivity of the X-ray detection panel 3 is lowered. Therefore, it is desirable that the thickness of the moistureproof cover 5 be as small as possible. In setting the thickness of the moisture-proof cover 5, the balance of various parameters such as stability of shape of the moisture-proof cover 5, strength to withstand manufacture, attenuation of X-ray 2 incident on the CsI / Tl phosphor layer 22 is taken into consideration Be done. As a result of consideration, the thickness of the moistureproof cover 5 is set in the range of 50 to 500 μm. In the present embodiment, the thickness of the moisture-proof cover 5 is set to 200 μm.
　光電変換基板21の外周部には、外部と接続するための複数のパッドが形成されている。複数のパッドは、光電変換基板21の駆動のための電気信号の入力及び出力信号の出力に使用される。 On the outer peripheral portion of the photoelectric conversion substrate 21, a plurality of pads for connecting to the outside are formed. The plurality of pads are used as an input of an electrical signal for driving the photoelectric conversion substrate 21 and an output of an output signal.
　Ｘ線検出パネル３および防湿カバー５の集合体は、薄い部材を積層して構成されているため、その集合体は、軽く、強度の低いものである。このため、Ｘ線検出パネル３は、粘着シートを介して支持基板４の平坦な一面に固定されている。支持基板４は、例えばアルミニウム合金で形成され、Ｘ線検出パネル３を支持して保持するために必要な強度を有している。 Since the assembly of the X-ray detection panel 3 and the moisture-proof cover 5 is configured by laminating thin members, the assembly is light and has low strength. For this reason, the X-ray detection panel 3 is fixed to one flat surface of the support substrate 4 via the adhesive sheet. The support substrate 4 is made of, for example, an aluminum alloy, and has the strength necessary to support and hold the X-ray detection panel 3.
　支持基板４の他面には、鉛プレート６と放熱絶縁シート７とを介して回路基板８が固定されている。回路基板８およびＸ線検出パネル３は、フレキシブル回路基板９を介して接続されている。フレキシブル回路基板９と光電変換基板21との接続には、ＡＣＦ（非等方性導電フィルム）を利用した熱圧着法が用いられる。この方法により、複数の微細な信号線の電気的接続が確保される。回路基板８には、フレキシブル回路基板９に対応するコネクタが実装されている。回路基板８は、コネクタなどを介してＸ線検出パネル３に電気的に接続されている。回路基板８は、Ｘ線検出パネル３を電気的に駆動し、かつ、Ｘ線検出パネル３からの出力信号を電気的に処理するものである。 The circuit board 8 is fixed to the other surface of the support substrate 4 via the lead plate 6 and the heat radiation insulation sheet 7. The circuit board 8 and the X-ray detection panel 3 are connected via the flexible circuit board 9. A thermocompression bonding method using an ACF (anisotropic conductive film) is used to connect the flexible circuit substrate 9 and the photoelectric conversion substrate 21. By this method, electrical connection of a plurality of fine signal lines is secured. A connector corresponding to the flexible circuit board 9 is mounted on the circuit board 8. The circuit board 8 is electrically connected to the X-ray detection panel 3 via a connector or the like. The circuit board 8 electrically drives the X-ray detection panel 3 and electrically processes an output signal from the X-ray detection panel 3.
　筐体11は、Ｘ線検出パネル３、支持基板４、防湿カバー５、回路基板８、鉛プレート６、放熱絶縁シート７、支柱10を収容している。筐体11は、Ｘ線検出パネル３と対向した位置に形成された開口を有している。支柱10は、筐体11に固定され、支持基板４を支持している。 The housing 11 accommodates the X-ray detection panel 3, the support substrate 4, the moisture-proof cover 5, the circuit substrate 8, the lead plate 6, the heat radiation insulation sheet 7, and the support 10. The housing 11 has an opening formed at a position facing the X-ray detection panel 3. The support 10 is fixed to the housing 11 and supports the support substrate 4.
　入射窓12は、筐体11の開口に取り付けられている。入射窓12はＸ線２を透過するため、Ｘ線２は入射窓12を透過してＸ線検出パネル３に入射される。入射窓12は、板状に形成され、筐体11の内部を保護する機能を有している。入射窓12は、Ｘ線吸収率の低い材料で薄く形成することが望ましい。これにより、入射窓12で生じる、Ｘ線２の散乱と、Ｘ線量の減衰とを低減することができる。 The entrance window 12 is attached to the opening of the housing 11. Since the entrance window 12 transmits the X-rays 2, the X-rays 2 pass through the entrance window 12 and are incident on the X-ray detection panel 3. The entrance window 12 is formed in a plate shape and has a function of protecting the inside of the housing 11. The entrance window 12 is desirably thinly formed of a material having a low X-ray absorptivity. Thereby, the scattering of the X-rays 2 and the attenuation of the X-ray generated at the entrance window 12 can be reduced.
　次に、図３はＣｓＩ／Ｔｌ蛍光体層22の発光スペクトルの波長と発光強度との関係を示すグラフである。発光スペクトルは、波長に対する積分値すなわち面積が同じになるように規格化している。サンプルには、本実施形態に対応した実施例１および２、比較例１～４が含まれる。 Next, FIG. 3 is a graph showing the relationship between the wavelength of the emission spectrum of the CsI / Tl phosphor layer 22 and the emission intensity. The emission spectrum is normalized so that the integral value or the area with respect to the wavelength becomes the same. The samples include Examples 1 and 2 corresponding to the present embodiment and Comparative Examples 1 to 4.
　そして、実施例１の発光スペクトルは、主ピークが５３０ｎｍにあり、さらに５６０～６００ｎｍに別のピークすなわち副ピークが埋没している。これをガウス関数で分解すると、図４に示すように、５３％の５３０ｎｍの主ピーク（P1）と、４７％の５８０ｎｍの副ピーク（P2）との複合形であることが分かった。すなわち、（実施例１の発光スペクトル）＝０．５３×（５３０ｎｍをピークとするガウス関数）＋０．４７×（５８０ｎｍをピークとするガウス関数）と表わされる。なお、５３０ｎｍの主ピークのガウス関数の標準偏差は２５ｎｍ、５８０ｎｍの副ピークのガウス関数の標準偏差は３０ｎｍとしている。なお、図４のＰは、ガウス関数による実施例１の発光スペクトルの計算値である。 The emission spectrum of Example 1 has a main peak at 530 nm, and another peak, ie, a secondary peak, is buried at 560 to 600 nm. When this was decomposed with a Gaussian function, as shown in FIG. 4, it was found to be a complex form of 53% of the 530 nm main peak (P1) and 47% of the 580 nm side peak (P2). That is, (emission spectrum of Example 1) = 0.53 × (Gaussian function with peak at 530 nm) + 0.47 × (Gauss function with peak at 580 nm). The standard deviation of the Gaussian function of the main peak of 530 nm is 25 nm, and the standard deviation of the Gaussian function of the minor peak of 580 nm is 30 nm. P in FIG. 4 is a calculated value of the emission spectrum of Example 1 based on the Gaussian function.
　実施例２の発光スペクトルは、主ピークが５４５ｎｍにあり、さらに、実施例１の発光スペクトルと同様に、５６０～６００ｎｍに別のピークすなわち副ピークが埋没している。これをガウス関数で分解すると、６０％の５４５ｎｍの主ピークと、４０％の５９５ｎｍの副ピークとの複合形であることが分かった。すなわち、（実施例２の発光スペクトル）＝０．６０×（５４５ｎｍをピークとするガウス関数）＋０．４０×（５９５ｎｍをピークとするガウス関数）と表わされる。 The emission spectrum of Example 2 has a main peak at 545 nm, and, similarly to the emission spectrum of Example 1, another peak or subpeak is buried at 560 to 600 nm. When this was decomposed with a Gaussian function, it was found to be a complex form of 60% of the 545 nm main peak and 40% of the 595 nm side peak. That is, (the emission spectrum of Example 2) = 0.60 × (Gauss function having a peak at 545 nm) + 0.40 × (Gauss function having a peak at 595 nm).
　実施例１および２のＣｓＩ／Ｔｌ蛍光体層22の特性は、ＣｓＩ／Ｔｌ蛍光体層22の製造過程のプロセスによって調整することができ、特にＴｌの結晶時のひずみの影響を操作することによって調整することが可能となっている。 The properties of the CsI / Tl phosphor layer 22 of Examples 1 and 2 can be adjusted by the process in the manufacturing process of the CsI / Tl phosphor layer 22, and in particular by manipulating the effect of strain during crystallization of Tl. It is possible to adjust.
　そして、これらのサンプルのＸ線照射前後の感度劣化を調査した結果は、図５のとおりである。比較例１～４のサンプルは、主ピークは５２０～５４５ｎｍであるが、比較例２および３は副ピークが無く、比較例１および４は主ピークよりも短波長側に副ピークが存在する。 And the result of having investigated sensitivity deterioration before and behind X-ray irradiation of these samples is as FIG. The samples of Comparative Examples 1 to 4 have a main peak of 520 to 545 nm, but Comparative Examples 2 and 3 have no side peak, and Comparative Examples 1 and 4 have a side peak on the shorter wavelength side than the main peak.
　それに対して、実施例１および２のＣｓＩ／Ｔｌ蛍光体層22は、主ピークこそ比較例１～４と同程度の５３０～５４５ｎｍであるが、副ピークが主ピークよりも長波長領域の５８０～５９５ｎｍにあるため、平面検出器およびＣＣＤ－ＤＲ装置で使用するセンサー感度との整合性が良く高感度特性が得られやすい。 On the other hand, in the CsI / Tl phosphor layers 22 of Examples 1 and 2, the main peak is 530 to 545 nm, which is comparable to that of Comparative Examples 1 to 4, but the side peak is 580 longer than the main peak. Since it is in the range of 595 nm, it is easy to obtain high sensitivity characteristics with good matching with the sensor sensitivity used in the flat panel detector and the CCD-DR apparatus.
　すなわち、実施例１および２のＣｓＩ／Ｔｌ蛍光体層22は、平面検出器で使用するアモルファスシリコンの感度ピーク（５５０ｎｍ）、および、ＣＣＤ－ＤＲ装置で使用するＣＣＤすなわち結晶シリコンの感度ピーク（５５０ｎｍより長波長側）と整合性があり、装置として高感度特性が得られやすい。 That is, the CsI / Tl phosphor layer 22 of Examples 1 and 2 has a sensitivity peak (550 nm) of amorphous silicon used in a flat panel detector and a sensitivity peak (550 nm) of CCD used in a CCD-DR apparatus, that is, crystalline silicon. It is consistent with the longer wavelength side) and it is easy to obtain high sensitivity characteristics as an apparatus.
　さらに、実施例１および２のＣｓＩ／Ｔｌ蛍光体層22は、１１５００ＲのＸ線を照射後の感度残存率が、比較例１と同等で、比較例２～４よりも優れている。比較例１は感度特性が実施例１および２のＣｓＩ／Ｔｌ蛍光体層22と比較して劣っている。 Furthermore, the CsI / Tl phosphor layers 22 of Examples 1 and 2 have sensitivity residual rates after irradiation with X-rays of 11500 R, which are equivalent to Comparative Example 1 and superior to Comparative Examples 2 to 4. Comparative Example 1 is inferior to the CsI / Tl phosphor layer 22 of Examples 1 and 2 in sensitivity characteristics.
　したがって、実施例１および２により、Ｘ線照射前の感度を向上させ、感度劣化を抑えたＣｓＩ／Ｔｌ蛍光体層22を得ることができた。 Therefore, according to Examples 1 and 2, it was possible to obtain the CsI / Tl phosphor layer 22 in which the sensitivity before X-ray irradiation was improved and the sensitivity deterioration was suppressed.
　また、図６は実施例１と比較例４とのＣｓＩ／Ｔｌ蛍光体層22の光吸収スペクトルの波長と光吸収率との関係を示すグラフである。なお、縦軸は光吸収率に対応した数値ではあるが、測定上、散乱により消失する光の寄与を評価することができなかったので、正確な光吸収率は算出されず、任意単位とした。 6 is a graph showing the relationship between the wavelength of the light absorption spectrum of the CsI / Tl phosphor layer 22 of Example 1 and Comparative Example 4 and the light absorptivity. Although the vertical axis is a numerical value corresponding to the light absorptivity, it was not possible to evaluate the contribution of the light which disappears due to scattering in measurement, so the correct light absorptivity is not calculated, and it is an arbitrary unit .
　実施例１と比較例４との両サンプルとも、Ｘ線照射前に比べてＸ線照射後（１０００時間後）の波長が長くなるほど透過率が上昇することと、５２０ｎｍと５６０ｎｍに光吸収のピークが存在した。そして、そのピークの大きさはＸ線照射を継続することにより増大することが確認された。 In both the samples of Example 1 and Comparative Example 4, the transmittance increases as the wavelength after X-ray irradiation (after 1000 hours) becomes longer than before X-ray irradiation, and the peak of light absorption at 520 nm and 560 nm Was present. And it was confirmed that the size of the peak increases by continuing X-ray irradiation.
　したがって、前述の感度との整合性に加え、ＣｓＩ／Ｔｌ蛍光体層22の発光スペクトルは、Ｘ線照射により光吸収率が増大する５２０～５６０ｎｍとは別のピークを持つことはＸ線耐性を向上させるための有効な手段であることが裏付けられた。 Therefore, in addition to the consistency with the sensitivity described above, the emission spectrum of CsI / Tl phosphor layer 22 has an X-ray resistance that is different from 520 to 560 nm, at which the light absorptance increases. It proved to be an effective means to improve.
　本実施形態によれば、ＣｓＩ／Ｔｌ蛍光体層22の発光スペクトルが５１０～５５０ｎｍの主ピークとともにその主ピークよりも長波長領域に副ピークを有することにより、ＣｓＩ／Ｔｌ蛍光体層22の感度を向上させるとともに、放射線によるＣｓＩ／Ｔｌ蛍光体層22の感度低下を低減することができる。 According to the present embodiment, the emission spectrum of the CsI / Tl phosphor layer 22 has a main peak of 510 to 550 nm and an auxiliary peak in a longer wavelength region than the main peak, whereby the sensitivity of the CsI / Tl phosphor layer 22 is obtained. While reducing the sensitivity of the CsI / Tl phosphor layer 22 due to radiation.
　副ピークは、５６０～６００ｎｍの波長領域であるため、ＣｓＩ／Ｔｌ蛍光体層22の感度を向上させるとともに、放射線によるＣｓＩ／Ｔｌ蛍光体層22の感度低下を低減することができる。副ピークの範囲は、５６０ｎｍより短波長側であると、光吸収ピークの影響があり、また、６００ｎｍより長波長側であると、平面検出器で使用するアモルファスシリコンの感度ピークと差が大きくなるため、５６０～６００ｎｍの波長領域が好ましい。 Since the side peak is in the wavelength region of 560 to 600 nm, the sensitivity of the CsI / Tl phosphor layer 22 can be improved, and the decrease in sensitivity of the CsI / Tl phosphor layer 22 due to radiation can be reduced. The range of the secondary peak is influenced by the light absorption peak when the wavelength is shorter than 560 nm, and when it is longer than 600 nm, the sensitivity peak and the difference between the sensitivity peaks of amorphous silicon used in the flat panel detector become large. Therefore, a wavelength range of 560 to 600 nm is preferable.
　次に、図７に第２の実施形態を示す。なお、第１の実施形態と同じ構成については同じ符号を用い、その構成および作用効果についての説明を省略する。 Next, FIG. 7 shows a second embodiment. The same reference numerals are used for the same configuration as the first embodiment, and the description of the configuration and the effects is omitted.
　図７は、シンチレータパネル31、およびシンチレータパネル31を用いた平面検出器である放射線検出器32を示す。 FIG. 7 shows a scintillator panel 31 and a radiation detector 32 which is a flat panel detector using the scintillator panel 31.
　シンチレータパネル31は、Ｘ線を透過する基板33上に反射層34を介してＣｓＩ／Ｔｌ蛍光体層22が形成されている。反射層34は、基板33とＣｓＩ／Ｔｌ蛍光体層22との間に介在している。ＣｓＩ／Ｔｌ蛍光体層22は防湿膜35によって覆われている。 In the scintillator panel 31, a CsI / Tl phosphor layer 22 is formed on a substrate 33 that transmits X-rays via a reflective layer 34. The reflective layer 34 is interposed between the substrate 33 and the CsI / Tl phosphor layer 22. The CsI / Tl phosphor layer 22 is covered by a moisture-proof film 35.
　シンチレータパネル31と光電変換基板36と組み合わせて放射線検出器32が構成されている。光電変換基板36は、受光素子としてのフォトダイオード37を備えており、第１の実施形態の光電変換基板21と同様に構成されている。 A radiation detector 32 is configured by combining the scintillator panel 31 and the photoelectric conversion substrate 36. The photoelectric conversion substrate 36 includes a photodiode 37 as a light receiving element, and is configured in the same manner as the photoelectric conversion substrate 21 of the first embodiment.
　そして、シンチレータパネル31およびシンチレータパネル31を用いた放射線検出器32においても、ＣｓＩ／Ｔｌ蛍光体層22を用いていることで、第１の実施形態と同様の作用効果を得ることができる。 Also in the radiation detector 32 using the scintillator panel 31 and the scintillator panel 31, by using the CsI / Tl phosphor layer 22, it is possible to obtain the same effect as that of the first embodiment.
　次に、図８に第３の実施形態を示す。なお、第１および第２の実施形態と同じ構成については同じ符号を用い、その構成および作用効果についての説明を省略する。 Next, FIG. 8 shows a third embodiment. The same reference numerals are used for the same configurations as the first and second embodiments, and the descriptions of the configurations and the effects are omitted.
　図８は、シンチレータパネル31を用いた放射線検出器としてのＣＣＤ－ＤＲ装置41を示す。ＣＣＤ－ＤＲ装置41は、筐体42を有し、この筐体42の一端にシンチレータパネル31が配置され、筐体42の内部に鏡面の反射板43およびレンズ44が設置され、筐体42の他端に受光素子（ＣＣＤ）45が設置されている。 FIG. 8 shows a CCD-DR device 41 as a radiation detector using the scintillator panel 31. The CCD-DR device 41 has a housing 42, the scintillator panel 31 is disposed at one end of the housing 42, a mirror reflector 43 and a lens 44 are provided inside the housing 42, and the housing 42 is A light receiving element (CCD) 45 is installed at the other end.
　そして、Ｘ線発生源（Ｘ線管）から放射されたＸ線２がシンチレータパネル31に入射し、ＣｓＩ／Ｔｌ蛍光体層22で変換した光46がＣｓＩ／Ｔｌ蛍光体層22の表面から出射される。このＣｓＩ／Ｔｌ蛍光体層22の表面にＸ線像が映し出され、このＸ線像を反射板43で反射するとともにレンズ44で集光して受光素子45に照射し、受光素子45でＸ線像を電気信号に変換して出力する。 Then, the X-ray 2 emitted from the X-ray source (X-ray tube) enters the scintillator panel 31 and the light 46 converted by the CsI / Tl phosphor layer 22 is emitted from the surface of the CsI / Tl phosphor layer 22 Be done. An X-ray image is projected on the surface of the CsI / Tl phosphor layer 22, and this X-ray image is reflected by the reflection plate 43 and collected by the lens 44 and irradiated onto the light receiving element 45. Converts an image into an electrical signal and outputs it.
　そして、ＣＣＤ－ＤＲ装置41においても、ＣｓＩ／Ｔｌ蛍光体層22を用いていることで、第１の実施形態と同様の作用効果を得ることができる。 Also in the CCD-DR device 41, by using the CsI / Tl phosphor layer 22, it is possible to obtain the same effect as that of the first embodiment.
　本発明のいくつかの実施形態を説明したが、これらの実施形態は、例として提示したものであり、発明の範囲を限定することは意図していない。これら新規な実施形態は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更を行うことができる。これら実施形態やその変形は、発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。 While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

Claims (6)

  1. 　複数の受光素子が配列された光電変換基板と、
    　前記光電変換基板上に形成され、放射線を光に変換する蛍光体層と、
    　を具備し、
    　前記蛍光体層の発光スペクトルは、５１０～５５０ｎｍの波長領域に主ピークを有するとともに、この主ピークよりも長波長領域に副ピークを有する
    　ことを特徴とする放射線検出器。     A photoelectric conversion substrate in which a plurality of light receiving elements are arranged;
    A phosphor layer formed on the photoelectric conversion substrate and converting radiation into light;
    Equipped with
    The emission spectrum of the phosphor layer has a main peak in a wavelength region of 510 to 550 nm and a sub peak in a longer wavelength region than the main peak.
  2. 　前記副ピークは、５６０～６００ｎｍの波長領域である
    　ことを特徴とする請求項１記載の放射線検出器。     The radiation detector according to claim 1, wherein the side peak is in a wavelength range of 560 to 600 nm.
  3. 　放射線を透過する基板と、
    　前記基板上に形成され、放射線を光に変換する蛍光体層と、
    　を具備し、
    　前記蛍光体層が放射線を光に変換する発光スペクトルは、５１０～５５０ｎｍの波長領域に主ピークを有するとともに、この主ピークよりも長波長領域に副ピークを有する
    　ことを特徴とするシンチレータパネル。     A substrate transparent to radiation,
    A phosphor layer formed on the substrate to convert radiation into light;
    Equipped with
    A scintillator panel, wherein an emission spectrum in which the phosphor layer converts radiation into light has a main peak in a wavelength region of 510 to 550 nm and a sub peak in a longer wavelength region than the main peak.
  4. 　前記副ピークは、５６０～６００ｎｍの波長領域である
    　ことを特徴とする請求項３記載のシンチレータパネル。     The scintillator panel according to claim 3, wherein the secondary peak is in a wavelength range of 560 to 600 nm.
  5. 　放射線を透過する基板と、前記基板上に形成され放射線を光に変換する蛍光体層と、を有するシンチレータパネルと、
    　前記シンチレータパネルの前記蛍光体層で変換された光を受光する複数の受光素子と、
    　を具備し、
    　前記蛍光体層が放射線を光に変換する発光スペクトルは、５１０～５５０ｎｍの波長領域に主ピークを有するとともに、この主ピークよりも長波長領域に副ピークを有する
    　ことを特徴とする放射線検出器。     A scintillator panel comprising: a substrate transparent to radiation; and a phosphor layer formed on the substrate and converting radiation into light;
    A plurality of light receiving elements for receiving the light converted by the phosphor layer of the scintillator panel;
    Equipped with
    A radiation detector characterized in that the emission spectrum in which the phosphor layer converts radiation into light has a main peak in a wavelength region of 510 to 550 nm and a sub peak in a longer wavelength region than the main peak.
  6. 　前記副ピークは、５６０～６００ｎｍの波長領域である
    　ことを特徴とする請求項５記載の放射線検出器。     The radiation detector according to claim 5, wherein the side peak is in a wavelength range of 560 to 600 nm.
PCT/JP2015/068568 2014-07-14 2015-06-26 Radiation detector and scintillator panel WO2016009815A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN201580038121.8A CN106796299B (en) 2014-07-14 2015-06-26 Radiation detector and scintillator panel
KR1020167036684A KR101903268B1 (en) 2014-07-14 2015-06-26 Radiation detector and scintillator panel

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2014-143969 2014-07-14
JP2014143969A JP2016020820A (en) 2014-07-14 2014-07-14 Radiation detector and scintillator panel

Publications (1)

Publication Number Publication Date
WO2016009815A1 true WO2016009815A1 (en) 2016-01-21

Family

ID=55078313

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2015/068568 WO2016009815A1 (en) 2014-07-14 2015-06-26 Radiation detector and scintillator panel

Country Status (4)

Country Link
JP (1) JP2016020820A (en)
KR (1) KR101903268B1 (en)
CN (1) CN106796299B (en)
WO (1) WO2016009815A1 (en)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08295878A (en) * 1995-04-26 1996-11-12 Yazaki Corp Scintillator and scintillator for radiation detector and radiation detector
JP2004151007A (en) * 2002-10-31 2004-05-27 Toshiba Corp Radiation detector
JP2008216041A (en) * 2007-03-05 2008-09-18 Konica Minolta Medical & Graphic Inc Radiographic image detector
JP2009503479A (en) * 2005-07-26 2009-01-29 シーメンス アクチエンゲゼルシヤフト Radiation converter and manufacturing method of radiation converter
JP2009068888A (en) * 2007-09-11 2009-04-02 Konica Minolta Medical & Graphic Inc Flat panel detector
JP2010145349A (en) * 2008-12-22 2010-07-01 Toshiba Corp Radiation detection apparatus

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATE519130T1 (en) * 2000-01-13 2011-08-15 Hamamatsu Photonics Kk RADIATION IMAGE SENSOR AND SCINTILLATOR PANEL
JP4653442B2 (en) 2004-08-19 2011-03-16 株式会社東芝 Radiation scintillator and radiation image detector
JP5089195B2 (en) * 2006-03-02 2012-12-05 キヤノン株式会社 Radiation detection apparatus, scintillator panel, radiation detection system, and method for manufacturing radiation detection apparatus
JP2013044725A (en) * 2011-08-26 2013-03-04 Fujifilm Corp Radiation detector and radiation image shooting device
JP2014009991A (en) * 2012-06-28 2014-01-20 Fujifilm Corp Radiation image detection device and manufacturing method thereof

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08295878A (en) * 1995-04-26 1996-11-12 Yazaki Corp Scintillator and scintillator for radiation detector and radiation detector
JP2004151007A (en) * 2002-10-31 2004-05-27 Toshiba Corp Radiation detector
JP2009503479A (en) * 2005-07-26 2009-01-29 シーメンス アクチエンゲゼルシヤフト Radiation converter and manufacturing method of radiation converter
JP2008216041A (en) * 2007-03-05 2008-09-18 Konica Minolta Medical & Graphic Inc Radiographic image detector
JP2009068888A (en) * 2007-09-11 2009-04-02 Konica Minolta Medical & Graphic Inc Flat panel detector
JP2010145349A (en) * 2008-12-22 2010-07-01 Toshiba Corp Radiation detection apparatus

Also Published As

Publication number Publication date
KR101903268B1 (en) 2018-10-01
KR20170010414A (en) 2017-01-31
CN106796299B (en) 2019-07-26
JP2016020820A (en) 2016-02-04
CN106796299A (en) 2017-05-31

Similar Documents

Publication Publication Date Title
US8049177B2 (en) Radiation image detection apparatus and manufacturing method of the same
JP5456013B2 (en) Radiation imaging device
KR101726464B1 (en) Radiation image conversion panel
US20140001367A1 (en) Radiological image detection apparatus and method of manufacturing the same
EP3244236B1 (en) Radiation detector and manufacturing method therefor
US9006662B2 (en) Radiological image detection device
JP5624447B2 (en) Radiation detection apparatus and scintillator panel manufacturing method
US20140001366A1 (en) Radiological image detection apparatus
US9720106B2 (en) Radiation detector and scintillator panel, and methods for manufacturing same
JP5749439B2 (en) Radiation image conversion panel
WO2016009815A1 (en) Radiation detector and scintillator panel
US9897705B2 (en) Radiation detector, scintillator panel, and method for manufacturing the same
KR20150046624A (en) X-ray detector
JP6508790B2 (en) Method of manufacturing radiation detector
JP5937185B2 (en) Manufacturing method of radiation image conversion panel
JP2023032732A (en) scintillator panel and radiation detector
JP2014081359A (en) Manufacturing method of radiation image detection device
WO2012056996A1 (en) Radiographic imaging unit
JP2015096820A (en) Radiation detector and radiation detector manufacturing method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15821810

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 20167036684

Country of ref document: KR

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15821810

Country of ref document: EP

Kind code of ref document: A1