WO2020090236A1 - Radiation monitor and radiation measurement method - Google Patents

Radiation monitor and radiation measurement method Download PDF

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Publication number
WO2020090236A1
WO2020090236A1 PCT/JP2019/035506 JP2019035506W WO2020090236A1 WO 2020090236 A1 WO2020090236 A1 WO 2020090236A1 JP 2019035506 W JP2019035506 W JP 2019035506W WO 2020090236 A1 WO2020090236 A1 WO 2020090236A1
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Prior art keywords
radiation
count rate
rate
heating
unit
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PCT/JP2019/035506
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French (fr)
Japanese (ja)
Inventor
田所　孝広
克宜 上野
上野　雄一郎
修一 畠山
耕一 岡田
名雲　靖
孝広 伊藤
渋谷　徹
敬介 佐々木
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株式会社日立製作所
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Publication of WO2020090236A1 publication Critical patent/WO2020090236A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors

Definitions

  • the present invention relates to a radiation monitor for measuring a radiation dose rate and a radiation measuring method.
  • the gas detector has a structure in which a metal wire is installed inside a container that contains gas.
  • the charged particles ionize the gas in the detector to generate electrons, which are amplified in a high electric field region near the metal wire and measured as an electric signal.
  • a scintillation detector emits light from a scintillation element when charged particles enter the scintillation element, converts the emitted light into an electrical signal using a photomultiplier tube, and measures the charged particle based on the electrical signal.
  • a large number of photons are generated when one charged particle is incident, and the number of generated photons is proportional to the energy of the incident charged particles. Therefore, the peak value of a pulsed electric signal proportional to the number of generated photons. Is measured to measure the energy of the incident charged particles.
  • an electron-hole pair generated by ionization by charged particles is generated in a region (depletion layer) formed around a junction surface where p-type and n-type semiconductors are joined, where electrons and holes are scarcely present.
  • a detector that detects charged particles based on electric signals generated by moving to p-type and n-type, respectively. Since a large number of electron-hole pairs are generated when one charged particle is incident, and the number of generated electron-hole pairs is proportional to the energy of the incident charged particles, it is proportional to the number of generated electron-hole pairs. The energy of the incident charged particles is measured by measuring the peak value of the pulsed electric signal.
  • detectors that detect neutron rays gas detectors, scintillation detectors, semiconductor detectors, etc. are known as well as charged particle detectors. However, similar to the charged particle detector described above, measurement in a high dose rate environment was difficult.
  • Patent Document 1 As a radiation monitor that can be measured in a high dose rate environment, there are technologies described in Patent Document 1 and Patent Document 2, for example. These documents describe a technique of transmitting light emitted from a radiation detection element through an optical fiber and measuring a dose rate based on the count rate of each photon.
  • Patent Document 1 describes a method of performing correction using a plurality of wavelengths, but a system for measuring each photon of a plurality of wavelengths is required, and the system becomes complicated. Moreover, there is no description of a technique for confirming and evaluating a background change due to radiation due to deterioration of a radiation monitor during plant operation.
  • the present invention has been made based on the above circumstances, and an object of the present invention is to provide a radiation monitor that accurately measures a dose rate even under a high temperature and high dose rate environment.
  • one of the representative aspects of the present invention is "a radiation detection element having a radiation detection element that generates a photon and emits light when radiation enters, and a radiation detection section having a housing that houses the radiation detection element, The photodetector that converts each photon generated by the radiation detector into an electric signal, the measuring device that calculates the radiation dose rate based on the count rate of the electric signal, and the radiation detector or the vicinity thereof.
  • a radiation monitor comprising: a heating unit for heating; the measuring device calculates a first count rate when a voltage is applied to the heating unit, and a second counting rate when the radiation enters the radiation detector.
  • a radiation monitor characterized by calculating a counting rate and converting a third counting rate obtained by subtracting the first counting rate from the second counting rate into a radiation dose rate.
  • the present invention it is possible to provide a radiation monitor that shows a correct dose rate even in a high temperature and high dose rate environment.
  • Example 1 of the present invention will be described with reference to FIGS. 1 to 3.
  • FIG. 1 is a configuration diagram of a radiation monitor according to a first embodiment of the present invention.
  • the radiation monitor 1 includes a radiation detection unit 10 that emits light when radiation enters, a heating device 20 that heats the radiation detection unit 10, an optical fiber 40, a light detection unit 70, and a measurement device 80.
  • An analysis / display device 90 is provided.
  • the radiation detecting unit 10 includes a radiation emitting element 11 made of a member obtained by adding a rare earth element to a ceramic base material, and a detector housing 12 that houses the radiation emitting element 11.
  • the radiation detection unit 10 is installed in a measurement area that measures radiation.
  • the radiation emitting element 11 is formed of a transparent material such as transparent yttrium / aluminum / garnet as a ceramic base material and a rare earth element such as ytterbium, neodymium, cerium or praseodymium contained in the transparent material. ing.
  • the light emission time of the radiation emitting element 11 (for example, yttrium-aluminum-garnet is YAG: Nd which is a material containing neodymium) has a longer optical decay time than that of NaI, BGO, or plastic scintillator used in conventional radiation detectors. You have selected one.
  • the heating device 20 includes a heating unit 21, an electric wire 22, and a voltage control device 23.
  • the heating unit 21 is, for example, a heater or the like, and is installed near the radiation detection unit 10 or the heating unit 21.
  • the voltage control device 23 controls the voltage applied to the heating unit 21.
  • the optical fiber 40 connects the radiation detection unit 10 and the light detection unit 70. More specifically, one end of the optical fiber 40 is connected to the radiation emitting element 11, and the other end of the optical fiber 40 is connected to the photodetector 70. In addition, in the matter that the optical fiber 40 is “connected” to the radiation emitting element 11, in addition to the configuration in which one end of the optical fiber 40 is in close contact with the radiation emitting element 11, one end of the optical fiber 40 is connected to the radiation emitting element 11. Includes configurations that are in close proximity.
  • the light detection unit 70 converts light (pulse light) guided to itself via the optical fiber 40 into an electric signal (light detection processing). More specifically, when one photon enters the photodetector 70, one electrical signal (pulse signal) is generated by photoelectric conversion.
  • a photodetector 70 for example, a photomultiplier tube or a photodiode can be used.
  • the measuring device 80 is a device that measures the count rate of the electric signal input from the photodetection unit 70, and is connected to the photodetection unit 70 via the wiring k1.
  • the measuring device 80 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read and expanded in the RAM, and the CPU executes various processes.
  • a CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the analysis / display device 90 is connected to the measurement device 80 via the wiring k2. Although not shown, it is configured to include electronic circuits such as a CPU, a ROM, a RAM, and various interfaces.
  • the analysis / display device 90 calculates the radiation dose rate based on the count rate of the electric signals input from the measurement device 80 (analysis process), and displays the calculation result.
  • the count rate of the electric signal and the radiation dose rate are in a proportional relationship, and the proportional coefficient is stored in advance in the analysis / display device 90.
  • the dose rate of radiation incident on the radiation detection element 11 and the number of photons generated by the radiation detection element 11 per unit time are in a proportional relationship. That is, the dose rate of the radiation incident on the radiation detection element 11 and the count rate of the electric signal (pulse signal) converted by the photodetection unit 70 are in a proportional relationship. Therefore, in the present embodiment, based on such a proportional relationship, the number (counting rate) of the electric signals output from the photodetecting section 70 to the measuring device 80 per unit time is converted into the radiation dose rate, and the dose is calculated. Calculate the rate. The details will be described below.
  • the electrons or rare earth atoms in the radiation light emitting element 11 transit to an excited state with a high energy level. Photons are generated when transitioning from the high excited state to the low energy level excited state or the ground state.
  • the photon generated by the radiation emitting element 11 passes through the optical fiber 40 and is detected by the photodetector 70.
  • the photodetector 70 detects each photon and converts it into an electric signal (pulse signal).
  • the photodetection unit 70 When the number of photons generated by the radiation detection element 11 per unit time (the total number) exceeds the upper limit value at which the photodetection unit 70 can perform photoelectric conversion, that is, the photodetection unit 70 has many photons.
  • An optical attenuation filter (not shown) may be additionally provided when incident and converting a plurality of photons into one electric signal.
  • a light attenuation filter may be provided in the front stage of the light detection unit 70.
  • the type of the radiation detection element 11 and the material / thickness of the housing 12 may be appropriately selected so that the optical attenuation filter becomes unnecessary. As a result, each photon incident on the photodetector 70 can be converted into an electric signal.
  • wavelength selection unit in front of the photodetection unit 70, it becomes possible to transmit photons of only a specific wavelength.
  • the wavelength selection unit one or a plurality of wavelength selection filters may be used, or a spectroscope may be used.
  • the counting rate of this electric signal is measured by the measuring device 80.
  • the analysis display device 90 derives the dose rate from the count rate using the proportional coefficient of the dose rate and the count rate measured in advance.
  • FIG. 2 is an explanatory diagram of the relationship between the count rate of each photon due to thermal radiation (radiation) and the wavelength of the photon. In the figure, light emission by radiation is also shown.
  • the rate of generation of photons due to thermal radiation (radiation) increases as the installation environment temperature increases and the wavelength of photons increases.
  • the background which is a photon due to thermal radiation (radiation)
  • the radiation monitor according to the present embodiment derives the count rate excluding the influence of photons generated by thermal radiation by the method described below.
  • the heating unit 21 heats the radiation detection unit 10. At this time, photons are generated from the radiation detection unit 10 according to the voltage applied to the heating unit 21 by the voltage control device 23.
  • the photodetector 70 detects the generated photons and converts them into electric signals.
  • the measuring device 80 measures the count rate of the converted electric signal.
  • FIG. 3 is an explanatory diagram of the relationship between the count rate of each photon and the power applied to the heating unit 21 when the dose rate of radiation is constant. Since the generation rate of photons due to thermal radiation (radiation) depends on the temperature of the radiation detection unit 10 and the temperature of the radiation detection unit 10 depends on the electric power applied to the heating unit 21, the radiation detection unit 10 is set by the heating unit 21. When heated, the photon count rate, which changes according to the change in the applied power from the voltage controller 23, is as shown in FIG. 3, for example.
  • the relationship between the photon count rate and the applied voltage at this time that is, the relationship between the photon generation rate due to thermal radiation (radiation) and the applied voltage is stored in advance in, for example, the analysis display device 90, and the measured value is used. Is corrected as follows.
  • FIG. 4 is an explanatory diagram of a method of calculating the dose rate excluding the effect of photons generated by thermal radiation when actually measured in a radiation environment and a high temperature environment.
  • the measurement values of the count rate under the radiation environment and the high temperature environment include the count rate by radiation and the count rate by thermal radiation. Therefore, the analysis display device 90 derives the count rate of radiation by subtracting the count rate of thermal radiation from the measured value of the count rate.
  • the counting rate due to heat radiation a value stored in advance or input using an external input device (not shown) or the like is used. Then, it is possible to convert the dose rate into a dose rate by using the proportional coefficient of the dose rate and the count rate measured in advance, and to calculate the dose rate without the influence of photons generated by thermal radiation.
  • FIG. 4 shows the case where the counting rate due to radiation is constant, but similarly when the counting rate due to radiation changes, the counting rate due to thermal radiation (radiation) is also subtracted from the counting rate under radiation and high temperature environment. By doing so, the counting rate due to radiation can be measured, and the dose rate excluding the effect of photons generated by thermal radiation can be calculated.
  • the second embodiment differs from the first embodiment in that the radiation monitor includes a thermometer side part, a signal line, a temperature measurement control device, and a database.
  • this embodiment is different from the first embodiment in that the value of the count rate of each photon with respect to the temperature measurement value is measured and recorded in the database before the radiation monitor is used for measuring radiation.
  • the other points are the same as in the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.
  • FIG. 5 is a configuration diagram of a radiation monitor according to the second embodiment of the present invention.
  • the radiation monitor 1 further includes a thermometer side portion 24, a signal line 25, a temperature measurement control device 26, and a database 27.
  • the temperature measuring unit 24 is a sensor that measures temperature, and is installed near the radiation detecting unit 10. The installation position may be inside the housing 12 or outside the housing 12. The temperature measured by the temperature measurement unit 24 is transmitted to the temperature measurement control device 26 via a signal line 25 connecting the thermometer side unit 24 and the temperature measurement control device 26.
  • the database 27 records the relationship between the measured value of the temperature measured by the thermometer side portion 24 and the count rate of the electric signal obtained by converting each photon by thermal radiation (radiation) measured by the measuring device 80.
  • Fig. 6 shows an example of the counting rate of each photon with respect to the measured value of temperature.
  • the heating unit 21 is used to heat the radiation detection unit 10 before the radiation monitor 1 is used for radiation measurement.
  • the voltage controller 23 changes the voltage applied to the heating unit 21 to change the temperature of the heating unit 21, and the thermometer side unit 24 measures the temperature in the vicinity of the radiation detection unit 10 or the heating unit 21.
  • thermometer side unit 24 As the measured value of the temperature in the vicinity of the radiation detection unit 10 or the heating unit 21 measured by the thermometer side unit 24 rises, electricity converted from each photon by thermal radiation (radiation) measured by the measuring device 80 The signal count rate increases.
  • the database 27 records the counting rate of each photon with respect to the measured value of the temperature measured by the thermometer side section 24.
  • the radiation monitor measures and records the counting rate of each photon for each temperature measurement value in the vicinity of the radiation detection unit 10 in advance, so that the temperature can be measured during radiation measurement by the radiation monitor. It is possible to derive the count rate due to thermal radiation (radiation) using the data recorded in the database from the measured value of the temperature measured.
  • the count rate due to radiation is derived by subtracting the count rate due to thermal radiation from the count rate measurement value, and converted to a dose rate by using the proportional coefficient between the dose rate and the count rate measured in advance. , It is possible to calculate the dose rate excluding the effect of photons generated by thermal radiation.
  • the third embodiment is different from the first embodiment in that the radiation monitor includes a light irradiation device, a light irradiation control device, a light branching unit, and a light branching optical filter.
  • the radiation monitor includes a light irradiation device, a light irradiation control device, a light branching unit, and a light branching optical filter.
  • the other points are the same as in the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.
  • FIG. 7 is a configuration diagram of a radiation monitor according to the third embodiment of the present invention.
  • the radiation monitor 1 further includes a light irradiation device 50, a light irradiation control device 51, a light branching unit 60, and a light branching optical filter 61.
  • the light irradiation device 50 is a semiconductor laser used when determining whether or not the radiation monitor 1 is functioning normally.
  • An LED Light Emitting Diode
  • the light irradiation device 50 emits light having a wavelength different from the emission wavelength of the radiation detection element 11.
  • the light branching unit 60 branches the light from the radiation detection unit 10 toward the light irradiation device 50 and the light detection unit 70.
  • the light irradiation control device 51 is a device that controls the light emission intensity of the light irradiation device 50, the pulse length and the light emission frequency during continuous light emission or pulse light emission, and is connected to the light irradiation device 50 via wiring. There is. Although not shown, the light irradiation control device 51 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read and expanded in the RAM, and the CPU executes various processes. The processing executed by the light irradiation control device 51 will be described later.
  • a CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the radiation detection unit 10 is connected to the light irradiation device 50 and the light detection unit 70, respectively, through an optical fiber and an optical branching unit 60 installed in the subsequent stage of the optical fiber.
  • the wavelength of the light irradiated using the light irradiation device 50 is set to a wavelength different from the wavelength of the light generated by irradiating the radiation light emitting element 11 with light.
  • the radiation emitting element 11 When the light emitted from the light irradiation device 50 is applied to the radiation emitting element 11 via the optical fiber and the light branching unit 60, the radiation emitting element 11 generates a number of photons proportional to the intensity of the applied light. It The generated photons and the photons reflected and scattered by the irradiated light in the radiation detection unit 10 are combined and enter the wavelength selection unit via the optical fiber and the optical branching unit 60.
  • the wavelength selection unit only photons of the wavelength emitted by the radiation emitting element 11 are incident on the photodetection unit 70.
  • the light detection unit 70 converts the detected photons into an electric signal.
  • the measuring device 80 measures the counting rate of the electric signal output from the photodetection unit 70.
  • the operation of the radiation monitor is checked and calibrated by using the relationship between the intensity of light from the light emitting unit and the count rate measured in advance.
  • the analysis / display device 90 executes a predetermined process based on the light intensity of the light irradiation device 50 and the count rate of electric pulses. That is, the analysis / display device 90 determines whether the light irradiation device 50 has deteriorated or other components (the radiation detection element 11, the optical fiber 40, etc.) have deteriorated, and displays the determination result. As a result, the reliability of the radiation monitor 1 can be increased more than ever before.
  • Example 4 is different from Example 2 in that the change over time of the count rate of the radiation monitor is calibrated.
  • the other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
  • Fig. 8 shows an example of changes over time in the counting rate of each photon with respect to the electric power applied to the heating unit.
  • the power supplied to the heating unit 21 during use can vary.
  • the count rate of heat radiation (radiation) when the voltage applied to the heating unit 21 is changed is derived by subtracting the count rate of each photon in the range of very small amount of electricity, and stored in the database 27. save.
  • the radiation count rate is derived based on the latest database, and this count rate and the dose rate measured in advance and the proportional coefficient of the count rate are used to convert the dose rate into a dose rate. Even in such a case, the counting rate due to thermal radiation can be accurately corrected.
  • the fifth embodiment is different from the second embodiment in that it is determined from the count rate of the radiation detection unit whether the radiation monitor is in water or in the air.
  • the other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
  • FIG. 9 shows an example of the relationship between the time change of the counting rate of each photon and the power application to the heating unit 21 when the radiation detection unit 10 is in water or in the air.
  • the radiation detection unit 10 when the radiation detection unit 10 is installed in water and in the air in advance, one photon before the application of voltage to the heating unit 21, before application of voltage, during application, application stop, and application stop The change of one count rate is measured and stored in the database 27.
  • the radiation detection unit 10 Based on the measured data of the count rate increase rate, the maximum count rate, and the count rate decrease rate of each photon, and the database measured in advance, whether the radiation detection unit 10 is in water or in air. It can be determined whether or not.
  • Example 6 differs from Example 2 in that the heating unit 21 is a laser heating device.
  • FIG. 10 is a configuration diagram of a radiation monitor according to the sixth embodiment of the present invention.
  • a laser heating device is used as the heating unit 21.
  • the laser heating device is connected to the radiation detection unit 10 via an optical fiber 40.
  • the laser light generated by the laser heating device is applied to the radiation detection unit 10 through the optical fiber 40.
  • the structure is such that the irradiated laser light does not enter the optical fiber that optically connects the radiation detection unit 10 and the light branching unit 70.
  • the temperature of the radiation detection unit 10 is changed by changing the intensity of the laser light applied to the radiation detection unit 10 and the irradiation time of the laser light.
  • the thermometer side part 24 measures the temperature in the vicinity of the radiation detection part 10.
  • the database 27 records the relationship between the measured value of the temperature measured by the thermometer side part 24 and the count rate of the electric signal obtained by converting each photon by thermal radiation (radiation) measured by the measuring device 80. Then, record the count rate of radiation due to thermal radiation in advance.
  • the count rate due to thermal radiation is subtracted from the measured count rate, the count rate due to radiation is derived, and it is converted into a dose rate by using the proportional coefficient between the dose rate and the count rate measured in advance.
  • the dose rate can be calculated without the effects of photons produced by the radiation.
  • Example 7 differs from Example 6 in the structure of the radiation detection unit.
  • the other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
  • FIG. 11 is a configuration diagram of a radiation monitor according to a seventh embodiment of the present invention
  • FIG. 12 is a configuration diagram of a radiation detection unit according to the seventh embodiment of the present invention.
  • the side surface of the radiation emitting element 11 that is not connected to the optical fiber 40 is covered with a metal or the like having a low heat radiation rate. This is the inside.
  • the side surface of the radiation emitting element 11 is covered with a substance having a high heat emission (emissivity) from the outside such as a metal having a low heat emission (emissivity). This is the outer surface.
  • the surface of the radiation emitting element 11 that is in contact with the optical fiber 40 is called the bottom surface, and the other surfaces are called the side surfaces.
  • the radiation emitting element 11 has an optical fiber for transmitting photons generated by the radiation emitting element 11 to generate light, and a laser heating device (heating unit 21) for heating the radiation emitting element 11.
  • the optical fiber and the optical fiber for measuring the temperature in the temperature measuring unit 24 are connected.
  • the laser light from the laser heating device which is the heating unit 21 is applied to the outer surface of the radiation emitting element 11. At this time, heating efficiency is improved by irradiating a substance having a high heat radiation rate, and the heat radiation from the outer surface (radiation rate) is improved by shielding the light from the inner surface of a metal having a low heat radiation rate. ) Does not mix in the radiation emitting element 11. Further, since the heat radiation (radiation) from the inner surface of a metal or the like having a low heat radiation (radiation) rate is small, the background of the heat radiation (radiation) in the radiation measurement can be suppressed to be small. Further, the temperature measuring unit 24 measures the heat radiation rate from the outer surface of the radiation measuring element 11 through the temperature measuring optical fiber. By measuring the heat radiation (radiation) intensity from a known substance having a high heat radiation (radiation) rate, it becomes possible to measure the temperature with high accuracy.
  • SYMBOLS 10 Radiation detection part, 11 ... Radiation emitting element, 12 ... Detector housing, 20 ... Heating device, 21 ... Heating part, 22 ... Electric wire, 23 ... Voltage control device, 24 ... Temperature measuring part, 25 ... Signal line, 26 ... temperature measurement control device, 27 ... database, 40 ... optical fiber, 50 ... light irradiation device, 51 ... light emitting unit control device, 60 ... optical branching unit, 61 ... optical branching optical filter, 70 ... photodetecting unit, 80 ... Measuring device, 90 ... Analysis / display device

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Abstract

The purpose of this invention is to provide a radiation monitor that highly accurately measures dose rate even in high-temperature and high-dose-rate environments. To achieve this purpose, the present invention provides a radiation monitor characterized by comprising a radiation detection unit having a radiation detection element that generates photons and emits light upon being struck with radiation and a housing for accommodating the radiation detection element, a light detection unit for converting each of the photons generated by the radiation detection unit into an electrical signal, a measurement device for calculating a radiation dose rate on the basis of electrical signal count rates, and a heating unit for heating the radiation detection unit or the vicinity thereof, wherein the measurement device calculates a first count rate when a voltage is applied to the heating unit, calculates a second count rate when radiation strikes a radiation detector, and converts a third count rate arrived at by subtracting the first count rate from the second count rate into a radiation dose rate.

Description

放射線モニタ及び放射線の測定方法Radiation monitor and radiation measurement method
　本発明は、放射線の線量率を測定する放射線モニタおよび放射線の測定方法に関する。 The present invention relates to a radiation monitor for measuring a radiation dose rate and a radiation measuring method.
　従来からの荷電粒子検出器としては、ガス検出器、シンチレーション検出器、及び、半導体検出器などが知られている。 As conventional charged particle detectors, gas detectors, scintillation detectors, semiconductor detectors, etc. are known.
　ガス検出器は、ガスを封入した容器内に金属ワイヤーを設置した構造のものである。荷電粒子が検出器内のガスを電離することによって電子を生成し、その電子を金属ワイヤー近傍の高電界領域で増幅することによって電気信号として測定する。 The gas detector has a structure in which a metal wire is installed inside a container that contains gas. The charged particles ionize the gas in the detector to generate electrons, which are amplified in a high electric field region near the metal wire and measured as an electric signal.
　シンチレーション検出器は、シンチレーション素子に荷電粒子が入射するとシンチレーション素子が発光し、その発光を光電子増倍管等を用いて電気信号に変換し、その電気信号をもとに荷電粒子を測定する。荷電粒子が１個入射した時に、多数の光子が生成し、生成した光子の個数が入射した荷電粒子のエネルギに比例することから、生成した光子の個数に比例するパルス状の電気信号の波高値を測定することで、入射した荷電粒子のエネルギを測定する。 A scintillation detector emits light from a scintillation element when charged particles enter the scintillation element, converts the emitted light into an electrical signal using a photomultiplier tube, and measures the charged particle based on the electrical signal. A large number of photons are generated when one charged particle is incident, and the number of generated photons is proportional to the energy of the incident charged particles. Therefore, the peak value of a pulsed electric signal proportional to the number of generated photons. Is measured to measure the energy of the incident charged particles.
　半導体検出器は、p型とn型の半導体を接合した接合面を中心に形成される電子や正孔がほとんど存在しない領域（空乏層）において、荷電粒子による電離によって生じた電子正孔対が、それぞれp型、n型に移動することによって生じる電気信号をもとに荷電粒子を検出する検出器である。荷電粒子が1個入射した時に、多数の電子正孔対が生成し、生成した電子正孔対の個数が入射した荷電粒子のエネルギに比例することから、生成した電子正孔対の個数に比例するパルス状の電気信号の波高値を測定することで、入射した荷電粒子のエネルギを測定する。 In a semiconductor detector, an electron-hole pair generated by ionization by charged particles is generated in a region (depletion layer) formed around a junction surface where p-type and n-type semiconductors are joined, where electrons and holes are scarcely present. , A detector that detects charged particles based on electric signals generated by moving to p-type and n-type, respectively. Since a large number of electron-hole pairs are generated when one charged particle is incident, and the number of generated electron-hole pairs is proportional to the energy of the incident charged particles, it is proportional to the number of generated electron-hole pairs. The energy of the incident charged particles is measured by measuring the peak value of the pulsed electric signal.
特開２０１７－１５６６２号公報JP, 2017-15662, A 特開２０１６－１１４３９２号公報JP, 2016-114392, A
　しかしながら、これらの荷電粒子線検出器を高線量環境下で用いる場合、以下のような課題がある。 However, when using these charged particle beam detectors in a high dose environment, there are the following problems.
　ガス検出器の場合は、ガス検出器に入射してくるガンマ線と、ガスや検出器容器材料とのコンプトン散乱による電子を数多く測定してしまうことから、荷電粒子との弁別が困難である。 In the case of a gas detector, it is difficult to distinguish it from charged particles because many gamma rays that enter the gas detector and electrons due to Compton scattering between the gas and the detector container material are measured.
　シンチレーション検出器の場合は、多数のガンマ線が同時にシンチレーション素子に入射してしまい、パルス状の電気信号が重なり合ってしまうことから、荷電粒子を正しく測定することが困難である。それを防ぐために、シンチレーション素子の周囲を鉛等の放射線遮蔽体で覆ってしまうと、荷電粒子が検出器内に入射することができなってしまうため、使用は困難である。 In the case of a scintillation detector, it is difficult to measure charged particles correctly because a large number of gamma rays enter the scintillation element at the same time and the pulsed electrical signals overlap. In order to prevent this, if the periphery of the scintillation element is covered with a radiation shield such as lead, charged particles cannot enter the detector, which makes it difficult to use.
　半導体検出器の場合は、多数のガンマ線が同時に半導体素子に入射してしまい、パルス状の電気信号が重なり合ってしまうことから、荷電粒子を正しく測定することが困難である。それを防ぐために、半導体素子の周囲を鉛等の放射線遮蔽体で覆ってしまうと、荷電粒子が検出器内に入射することができなってしまうため、使用は困難である。 In the case of semiconductor detectors, it is difficult to correctly measure charged particles because a large number of gamma rays enter the semiconductor element at the same time and pulse-shaped electric signals overlap each other. If the periphery of the semiconductor element is covered with a radiation shield such as lead in order to prevent this, charged particles cannot enter the detector, which makes it difficult to use.
　中性子線を検出する検出器に関しては、荷電粒子検出器と同様に、ガス検出器、シンチレーション検出器、半導体検出器などが知られている。しかし、上記の荷電粒子検出器と同様に、高線量率環境下における測定が困難だった。 Regarding detectors that detect neutron rays, gas detectors, scintillation detectors, semiconductor detectors, etc. are known as well as charged particle detectors. However, similar to the charged particle detector described above, measurement in a high dose rate environment was difficult.
　これに対し、高線量率環境下で測定可能な放射線モニタとして、例えば特許文献１や特許文献２に記載の技術がある。これらの文献には、放射線検出素子から発せられた光を光ファイバで伝送し、光子1個1個の計数率をもとに線量率を測定する技術について記載されている。 On the other hand, as a radiation monitor that can be measured in a high dose rate environment, there are technologies described in Patent Document 1 and Patent Document 2, for example. These documents describe a technique of transmitting light emitted from a radiation detection element through an optical fiber and measuring a dose rate based on the count rate of each photon.
　しかしながら、放射線モニタを高温環境下で使用する場合は、輻射によるバックグラウンドが存在することから、その補正方法が必要となっている。特許文献１には複数の波長を用いて補正する方法が記載されているが、複数の波長の光子１個１個を測定するシステムが必要となり、システムが複雑化してしまう。また、プラント運転中における放射線モニタの劣化等による輻射によるバックグラウンドの変化を確認し評価する技術については記載されていない。 However, when using a radiation monitor in a high temperature environment, there is a background due to radiation, so a correction method for it is necessary. Patent Document 1 describes a method of performing correction using a plurality of wavelengths, but a system for measuring each photon of a plurality of wavelengths is required, and the system becomes complicated. Moreover, there is no description of a technique for confirming and evaluating a background change due to radiation due to deterioration of a radiation monitor during plant operation.
　本発明は、以上のような事情に基づいてなされたものであり、高温及び高線量率環境下においても、高精度に線量率を測定する放射線モニタを提供することを目的とする。 The present invention has been made based on the above circumstances, and an object of the present invention is to provide a radiation monitor that accurately measures a dose rate even under a high temperature and high dose rate environment.
　上記課題を解決するために、代表的な本発明の一つは、「放射線が入射すると光子を生成して発光する放射線検出素子と、放射線検出素子を収容するハウジングとを有する放射線検出部と、放射線検出部で生成された光子１個１個を電気信号に変換する光検出部と、電気信号の計数率に基づいて、放射線の線量率を算出する測定装置と、放射線検出部またはその近傍を加熱する加熱部と、を備えた放射線モニタであって、測定装置は、加熱部に電圧を印加したときに第１の計数率を算出し、放射線検出器に放射線が入射したときに第２の計数率を算出し、第２の計数率から第１の計数率を引いた第３の計数率を放射線の線量率に換算することを特徴とする放射線モニタ。」としたものである。 In order to solve the above problems, one of the representative aspects of the present invention is "a radiation detection element having a radiation detection element that generates a photon and emits light when radiation enters, and a radiation detection section having a housing that houses the radiation detection element, The photodetector that converts each photon generated by the radiation detector into an electric signal, the measuring device that calculates the radiation dose rate based on the count rate of the electric signal, and the radiation detector or the vicinity thereof. A radiation monitor comprising: a heating unit for heating; the measuring device calculates a first count rate when a voltage is applied to the heating unit, and a second counting rate when the radiation enters the radiation detector. A radiation monitor characterized by calculating a counting rate and converting a third counting rate obtained by subtracting the first counting rate from the second counting rate into a radiation dose rate. "
　本発明によれば、高温及び高線量率環境下においても、正しい線量率を示す放射線モニタを提供することが可能となる。 According to the present invention, it is possible to provide a radiation monitor that shows a correct dose rate even in a high temperature and high dose rate environment.
本発明の実施例１に係る放射線モニタの構成図である。It is a block diagram of the radiation monitor which concerns on Example 1 of this invention. 熱放射（輻射）による光子１個１個の計数率と光子の波長との関係の説明図である。It is explanatory drawing of the relationship between the count rate of each photon and the wavelength of a photon by thermal radiation (radiation). 線量率を一定とした場合における、光子１個１個の計数率と加熱部に印加する電力の関係の説明図である。It is explanatory drawing of the relationship between the count rate of each photon and the electric power applied to a heating part, when a dose rate is made constant. 熱放射により生成された光子の影響を除いた線量率を算出する方法の説明図である。It is explanatory drawing of the method of calculating the dose rate which removed the influence of the photon produced by thermal radiation. 本発明の実施例２に係る放射線モニタの構成図である。It is a block diagram of the radiation monitor which concerns on Example 2 of this invention. 温度の測定値に対する光子１個１個の計数率の一例。An example of the counting rate of each photon with respect to the measured value of temperature. 本発明の実施例３に係る放射線モニタの構成図である。It is a block diagram of the radiation monitor which concerns on Example 3 of this invention. 加熱部に与える電力に対する光子１個１個の計数率の経時変化の説明図である。It is explanatory drawing of the time-dependent change of the count rate of each photon with respect to the electric power given to a heating part. 放射線発光素子部が水中または気中にある場合の光子１個１個の計数率の時間変化と加熱部への電力印加の関係の説明図である。It is explanatory drawing of the time change of the count rate of each photon and the power application to a heating part when a radiation light emitting element part is in water or air. 本発明の実施例６に係る放射線モニタの構成図である。It is a block diagram of the radiation monitor which concerns on Example 6 of this invention. 本発明の実施例７に係る放射線モニタの構成図である。It is a block diagram of the radiation monitor which concerns on Example 7 of this invention. 本発明の実施例７に係る放射線検出部の構成図である。It is a block diagram of the radiation detection part which concerns on Example 7 of this invention.
　以下、本発明の実施に好適な実施例について説明する。尚、下記はあくまでも実施の例に過ぎず、下記具体的内容に発明自体が限定されることを意図する趣旨ではない。 Hereinafter, preferred embodiments for carrying out the present invention will be described. It should be noted that the following is merely an example of the embodiment, and the invention itself is not intended to be limited to the following specific contents.
　以下、本発明の実施例を、図面を参照して説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　本発明の実施例１を図１乃至図３に基づいて説明する。 Example 1 of the present invention will be described with reference to FIGS. 1 to 3.
　まず、本実施例に係る放射線モニタの構成について説明する。図１は、本発明の実施例１に係る放射線モニタの構成図である。 First, the configuration of the radiation monitor according to the present embodiment will be described. 1 is a configuration diagram of a radiation monitor according to a first embodiment of the present invention.
　本実施例に係る放射線モニタ１は、放射線が入射すると発光する放射線検出部１０と、放射線検出部１０を加熱する加熱装置２０と、光ファイバ４０と、光検出部７０と、測定装置８０と、解析・表示装置９０を備える。 The radiation monitor 1 according to the present embodiment includes a radiation detection unit 10 that emits light when radiation enters, a heating device 20 that heats the radiation detection unit 10, an optical fiber 40, a light detection unit 70, and a measurement device 80. An analysis / display device 90 is provided.
　放射線検出部１０は、セラミック母材に希土類元素を添加した部材からなる放射線発光素子１１と、放射線発光素子１１を収容する検出器ハウジング１２を備える。放射線検出部１０は、放射線を測定する測定エリアに設置される。 The radiation detecting unit 10 includes a radiation emitting element 11 made of a member obtained by adding a rare earth element to a ceramic base material, and a detector housing 12 that houses the radiation emitting element 11. The radiation detection unit 10 is installed in a measurement area that measures radiation.
　放射線発光素子１１は、セラミック母材としての透明イットリウム・アルミ・ガーネットなどの光透過性材料と、この光透過性材料中に含有されたイッテルビウム、ネオジム、セリウム、プラセオジウムなどの希土類元素とにより形成されている。放射線発光素子１１（例えばイットリウム・アルミ・ガーネットは、ネオジムを含有させた材料であるYAG:Nd）の光減衰時間は、従来の放射線検出器に用いられるNaI、BGO、プラスチックシンチレータと比較して長いものを選択している。 The radiation emitting element 11 is formed of a transparent material such as transparent yttrium / aluminum / garnet as a ceramic base material and a rare earth element such as ytterbium, neodymium, cerium or praseodymium contained in the transparent material. ing. The light emission time of the radiation emitting element 11 (for example, yttrium-aluminum-garnet is YAG: Nd which is a material containing neodymium) has a longer optical decay time than that of NaI, BGO, or plastic scintillator used in conventional radiation detectors. You have selected one.
　加熱装置２０は、加熱部２１と、電線２２と、電圧制御装置２３とを備える。 The heating device 20 includes a heating unit 21, an electric wire 22, and a voltage control device 23.
　加熱部２１は、例えばヒータ等であり、放射線検出部１０または加熱部２１の近傍に設置される。 The heating unit 21 is, for example, a heater or the like, and is installed near the radiation detection unit 10 or the heating unit 21.
　電圧制御装置２３は、加熱部２１に印加する電圧を制御する。 The voltage control device 23 controls the voltage applied to the heating unit 21.
　光ファイバ４０は、放射線検出部１０と光検出部７０を接続する。より具体的には、光ファイバ４０の一端が放射線発光素子１１に接続され、光ファイバ４０の他端が光検出部７０に接続される。なお、光ファイバ４０が放射線発光素子１１に「接続」されるという事項には、光ファイバ４０の一端が放射線発光素子１１に密接される構成の他、光ファイバ４０の一端が放射線発光素子１１に近接している構成も含まれる。 The optical fiber 40 connects the radiation detection unit 10 and the light detection unit 70. More specifically, one end of the optical fiber 40 is connected to the radiation emitting element 11, and the other end of the optical fiber 40 is connected to the photodetector 70. In addition, in the matter that the optical fiber 40 is “connected” to the radiation emitting element 11, in addition to the configuration in which one end of the optical fiber 40 is in close contact with the radiation emitting element 11, one end of the optical fiber 40 is connected to the radiation emitting element 11. Includes configurations that are in close proximity.
　光検出部７０は、光ファイバ４０を介して、自身に導かれる光（パルス光）を電気信号に変換する（光検出処理）。より具体的には、光検出部７０に１つの光子が入射すると、光電変換によって１つの電気信号（パルス信号）が生成されるようになっている。このような光検出部７０として、例えば、光電子増倍管やフォトダイオードを用いることができる。 The light detection unit 70 converts light (pulse light) guided to itself via the optical fiber 40 into an electric signal (light detection processing). More specifically, when one photon enters the photodetector 70, one electrical signal (pulse signal) is generated by photoelectric conversion. As such a photodetector 70, for example, a photomultiplier tube or a photodiode can be used.
　測定装置８０は、光検出部７０から入力される電気信号の計数率を測定する装置であり、配線ｋ１を介して光検出部７０に接続されている。測定装置８０は、図示はしないが、ＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）、各種インタフェース等の電子回路を含んで構成されている。そして、ＲＯＭに記憶されたプログラムを読み出してＲＡＭに展開し、ＣＰＵが各種処理を実行する。 The measuring device 80 is a device that measures the count rate of the electric signal input from the photodetection unit 70, and is connected to the photodetection unit 70 via the wiring k1. Although not shown, the measuring device 80 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read and expanded in the RAM, and the CPU executes various processes.
　解析・表示装置９０は、配線ｋ２を介して測定装置８０に接続されている。図示はしないが、ＣＰＵ、ＲＯＭ、ＲＡＭ、各種インタフェース等の電子回路を含んで構成される。解析・表示装置９０は、測定装置８０ら入力される電気信号の計数率に基づいて、放射線の線量率を算出し（解析処理）、その算出結果を表示する。なお、電気信号の計数率と、放射線の線量率と、は比例関係にあり、その比例係数が解析・表示装置９０に予め記憶されている。 The analysis / display device 90 is connected to the measurement device 80 via the wiring k2. Although not shown, it is configured to include electronic circuits such as a CPU, a ROM, a RAM, and various interfaces. The analysis / display device 90 calculates the radiation dose rate based on the count rate of the electric signals input from the measurement device 80 (analysis process), and displays the calculation result. The count rate of the electric signal and the radiation dose rate are in a proportional relationship, and the proportional coefficient is stored in advance in the analysis / display device 90.
　次に、本実施例に係る放射線モニタの測定原理と動作について説明する。 Next, the measurement principle and operation of the radiation monitor according to the present embodiment will be described.
　放射線検出素子１１に入射する放射線の線量率と、放射線検出素子１１で生成される単位時間当たりの光子の個数と、は比例関係にあることが分かっている。すなわち、放射線検出素子１１に入射する放射線の線量率と、光検出部７０で変換された電気信号（パルス信号）の計数率と、は比例関係にある。そこで、本実施例では、このような比例関係に基づき、光検出部７０から測定装置８０に出力される電気信号の単位時間当たりの個数（計数率）を、放射線の線量率に換算し、線量率を算出する。以下、詳細に説明する。 It is known that the dose rate of radiation incident on the radiation detection element 11 and the number of photons generated by the radiation detection element 11 per unit time are in a proportional relationship. That is, the dose rate of the radiation incident on the radiation detection element 11 and the count rate of the electric signal (pulse signal) converted by the photodetection unit 70 are in a proportional relationship. Therefore, in the present embodiment, based on such a proportional relationship, the number (counting rate) of the electric signals output from the photodetecting section 70 to the measuring device 80 per unit time is converted into the radiation dose rate, and the dose is calculated. Calculate the rate. The details will be described below.
　放射性発光素子１１に放射線又は光が入射すると、放射線発光素子１１内の電子または希土類原子がエネルギ準位の高い励起状態に遷移する。その高い励起状態から、エネルギ準位の低い励起状態または基底状態に遷移するときに光子が生成される。 When radiation or light is incident on the radiative light emitting element 11, the electrons or rare earth atoms in the radiation light emitting element 11 transit to an excited state with a high energy level. Photons are generated when transitioning from the high excited state to the low energy level excited state or the ground state.
　放射線発光素子１１で生成された光子は、光ファイバ４０を通って光検出部７０で検出される。光検出部７０では、光子１個１個を検出し、電気信号（パルス信号）に変換する。 The photon generated by the radiation emitting element 11 passes through the optical fiber 40 and is detected by the photodetector 70. The photodetector 70 detects each photon and converts it into an electric signal (pulse signal).
　なお、放射線検出素子１１で単位時間あたりに生成される光子の個数が（合計の個数）が、光検出部７０で光電変換が可能な上限値を超える場合、すなわち光検出部７０に光子が多数入射し、複数の光子を１つの電気信号に変換してしまう場合には、光減衰フィルタ（図示せず）を追加で設けてもよい。例えば、光検出部７０の前段に光減衰フィルタを設けてもよい。また、光減衰フィルタが不要となるように、放射線検出素子１１の種類やハウジング１２の材料・厚さを適宜に選択してもよい。これにより、光検出部７０が入射した１個１個の光子を、１個１個の電気信号に変換することができる。 When the number of photons generated by the radiation detection element 11 per unit time (the total number) exceeds the upper limit value at which the photodetection unit 70 can perform photoelectric conversion, that is, the photodetection unit 70 has many photons. An optical attenuation filter (not shown) may be additionally provided when incident and converting a plurality of photons into one electric signal. For example, a light attenuation filter may be provided in the front stage of the light detection unit 70. Further, the type of the radiation detection element 11 and the material / thickness of the housing 12 may be appropriately selected so that the optical attenuation filter becomes unnecessary. As a result, each photon incident on the photodetector 70 can be converted into an electric signal.
　また、光検出部７０の前段に波長選択部を設置することで、特定の波長のみの光子を透過させることが可能となる。波長選択部には、一枚または複数枚の波長選択フィルタを用いても良いし、分光器を用いても良い。 Also, by installing a wavelength selection unit in front of the photodetection unit 70, it becomes possible to transmit photons of only a specific wavelength. As the wavelength selection unit, one or a plurality of wavelength selection filters may be used, or a spectroscope may be used.
　光検出部７０で電気信号に変換した後、この電気信号の計数率を測定装置８０で測定する。放射線検出部１０における線量率とこの電気信号の計数率には、比例関係がある。解析表示装置９０は、事前に測定した線量率と計数率の比例係数を用いて、計数率から線量率を導出する。 After being converted into an electric signal by the light detection unit 70, the counting rate of this electric signal is measured by the measuring device 80. There is a proportional relationship between the dose rate in the radiation detection unit 10 and the count rate of this electric signal. The analysis display device 90 derives the dose rate from the count rate using the proportional coefficient of the dose rate and the count rate measured in advance.
　ここで、放射線検出部１０の設置環境温度が高くなると、放射線検出部１０の構成部材から熱放射（輻射）による光子の生成が起こる。図２は、熱放射（輻射）による光子１個１個の計数率と光子の波長の関係の説明図である。図中には、放射線による発光も合わせて示している。熱放射（輻射）による光子の生成率は、設置環境温度が高いほど大きく、光子の波長が長いほど大きい。設置環境温度が高くなるに従って、熱放射（輻射）による光子であるバックグラウンドが高くなり、放射線の照射により発光する波長の光子を正確に測定できなくなる。このとき、放射線による線量率を導出するためには、熱放射（輻射）による光子の影響を補正する必要がある。 Here, when the installation environment temperature of the radiation detection unit 10 rises, photons are generated by thermal radiation from the constituent members of the radiation detection unit 10. FIG. 2 is an explanatory diagram of the relationship between the count rate of each photon due to thermal radiation (radiation) and the wavelength of the photon. In the figure, light emission by radiation is also shown. The rate of generation of photons due to thermal radiation (radiation) increases as the installation environment temperature increases and the wavelength of photons increases. As the installation environment temperature rises, the background, which is a photon due to thermal radiation (radiation), rises, and it becomes impossible to accurately measure a photon having a wavelength emitted by irradiation of radiation. At this time, in order to derive the dose rate due to radiation, it is necessary to correct the influence of photons due to thermal radiation.
　そこで本実施例に係る放射線モニタは、次に説明する方法により、熱放射により生成された光子の影響を除いた計数率を導出する。 Therefore, the radiation monitor according to the present embodiment derives the count rate excluding the influence of photons generated by thermal radiation by the method described below.
　まず、加熱部２１が放射線検出部１０を加熱する。このとき、電圧制御装置２３が加熱部２１に印加した電圧に従って、放射線検出部１０から光子が生成される。光検出部７０は、生成された光子を検出して電気信号に変換する。測定装置８０は、変換された電気信号の計数率を測定する。 First, the heating unit 21 heats the radiation detection unit 10. At this time, photons are generated from the radiation detection unit 10 according to the voltage applied to the heating unit 21 by the voltage control device 23. The photodetector 70 detects the generated photons and converts them into electric signals. The measuring device 80 measures the count rate of the converted electric signal.
　図３は、放射線による線量率を一定とした場合における、光子１個１個の計数率と加熱部２１に印加する電力との関係の説明図である。熱放射（輻射）による光子の生成率が放射線検出部１０の温度に依存し、放射線検出部１０の温度が加熱部２１に印加する電力に依存することから、放射線検出部１０を加熱部２１で加熱したとき、電圧制御装置２３からの印加電力の変化に従って変化する光子の計数率は、例えば図３のようになる。このときの光子の計数率と印加電圧の関係、すなわち熱放射（輻射）による光子の生成率と印加電圧の関係を、事前に例えば解析表示装置９０に記憶しておき、これを用いて測定値を次のように補正する。 FIG. 3 is an explanatory diagram of the relationship between the count rate of each photon and the power applied to the heating unit 21 when the dose rate of radiation is constant. Since the generation rate of photons due to thermal radiation (radiation) depends on the temperature of the radiation detection unit 10 and the temperature of the radiation detection unit 10 depends on the electric power applied to the heating unit 21, the radiation detection unit 10 is set by the heating unit 21. When heated, the photon count rate, which changes according to the change in the applied power from the voltage controller 23, is as shown in FIG. 3, for example. The relationship between the photon count rate and the applied voltage at this time, that is, the relationship between the photon generation rate due to thermal radiation (radiation) and the applied voltage is stored in advance in, for example, the analysis display device 90, and the measured value is used. Is corrected as follows.
　図４は、実際に放射線環境下かつ高温環境下で測定した場合における、熱放射により生成された光子の影響を除いた線量率を算出する方法の説明図である。放射線環境下かつ高温環境下の計数率の測定値には、放射線による計数率と熱放射による計数率が含まれる。そこで、解析表示装置９０は、計数率の測定値から、熱放射による計数率を差分することで、放射線による計数率を導出する。ここで、熱放射による計数率は、事前に記憶した、または外部の入力装置（図示しない）等を用いて入力した値を用いる。そして、事前に測定した線量率と計数率の比例係数を用いることで線量率に変換し、熱放射により生成された光子の影響を除いた線量率を算出することができる。 FIG. 4 is an explanatory diagram of a method of calculating the dose rate excluding the effect of photons generated by thermal radiation when actually measured in a radiation environment and a high temperature environment. The measurement values of the count rate under the radiation environment and the high temperature environment include the count rate by radiation and the count rate by thermal radiation. Therefore, the analysis display device 90 derives the count rate of radiation by subtracting the count rate of thermal radiation from the measured value of the count rate. Here, as the counting rate due to heat radiation, a value stored in advance or input using an external input device (not shown) or the like is used. Then, it is possible to convert the dose rate into a dose rate by using the proportional coefficient of the dose rate and the count rate measured in advance, and to calculate the dose rate without the influence of photons generated by thermal radiation.
　図４は、放射線による計数率が一定の場合を示したが、放射線による計数率が変化する場合も同様に、放射線及び高温環境下での計数率から、熱放射（輻射）による計数率を差分することで放射線による計数率を測定し、熱放射により生成された光子の影響を除いた線量率を算出することができる。 FIG. 4 shows the case where the counting rate due to radiation is constant, but similarly when the counting rate due to radiation changes, the counting rate due to thermal radiation (radiation) is also subtracted from the counting rate under radiation and high temperature environment. By doing so, the counting rate due to radiation can be measured, and the dose rate excluding the effect of photons generated by thermal radiation can be calculated.
　実施例２は、放射線モニタが、温度計側部と、信号線と、温度測定制御装置と、データベースとを備える点が、実施例１とは異なる。また本実施例では、放射線モニタを放射線の測定に使用する前に、温度測定値に対する光子１個１個の計数率の値を測定してデータベースに記録する点が、実施例１とは異なる。なお、その他については実施例１と同様である。したがって、実施例１とは異なる部分について説明し、重複する部分については説明を省略する。 The second embodiment differs from the first embodiment in that the radiation monitor includes a thermometer side part, a signal line, a temperature measurement control device, and a database. In addition, this embodiment is different from the first embodiment in that the value of the count rate of each photon with respect to the temperature measurement value is measured and recorded in the database before the radiation monitor is used for measuring radiation. The other points are the same as in the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.
　図５は、本発明の実施例２に係る放射線モニタの構成図である。 FIG. 5 is a configuration diagram of a radiation monitor according to the second embodiment of the present invention.
　本実施例に係る放射線モニタ１は、温度計側部２４と、信号線２５と、温度測定制御装置２６と、データベース２７をさらに備える。 The radiation monitor 1 according to the present embodiment further includes a thermometer side portion 24, a signal line 25, a temperature measurement control device 26, and a database 27.
　温度測定部２４は、温度を測定するセンサなどであり、放射線検出部１０の近傍に設置される。設置される位置はハウジング１２の内部であっても良いし、ハウジング１２の外部であっても良い。温度測定部２４で測定された温度は、温度計側部２４と温度測定制御装置２６とを接続する信号線２５を通して、温度測定制御装置２６に送信される。 The temperature measuring unit 24 is a sensor that measures temperature, and is installed near the radiation detecting unit 10. The installation position may be inside the housing 12 or outside the housing 12. The temperature measured by the temperature measurement unit 24 is transmitted to the temperature measurement control device 26 via a signal line 25 connecting the thermometer side unit 24 and the temperature measurement control device 26.
　データベース２７は、温度計側部２４で測定した温度の測定値と、測定装置８０で測定される熱放射（輻射）による光子１個１個を変換した電気信号の計数率の関係を記録する。 The database 27 records the relationship between the measured value of the temperature measured by the thermometer side portion 24 and the count rate of the electric signal obtained by converting each photon by thermal radiation (radiation) measured by the measuring device 80.
　図６に温度の測定値に対する光子１個１個の計数率の一例を示す。 Fig. 6 shows an example of the counting rate of each photon with respect to the measured value of temperature.
　放射線モニタ１を放射線測定に使用する前の段階で、加熱部２１を用いて放射線検出部１０を加熱する。電圧制御装置２３は、加熱部２１に印加する電圧を変化して加熱部２１の温度を変化させ、温度計側部２４は放射線検出部１０または加熱部２１の近傍の温度を測定する。 The heating unit 21 is used to heat the radiation detection unit 10 before the radiation monitor 1 is used for radiation measurement. The voltage controller 23 changes the voltage applied to the heating unit 21 to change the temperature of the heating unit 21, and the thermometer side unit 24 measures the temperature in the vicinity of the radiation detection unit 10 or the heating unit 21.
　温度計側部２４が測定する放射線検出部１０または加熱部２１の近傍の温度の測定値が上昇するに従って、測定装置８０で測定される熱放射（輻射）による光子１個１個を変換した電気信号の計数率が増加する。 As the measured value of the temperature in the vicinity of the radiation detection unit 10 or the heating unit 21 measured by the thermometer side unit 24 rises, electricity converted from each photon by thermal radiation (radiation) measured by the measuring device 80 The signal count rate increases.
　データベース２７は、温度計側部２４で測定された温度の測定値に対する光子１個１個の計数率を記録する。 The database 27 records the counting rate of each photon with respect to the measured value of the temperature measured by the thermometer side section 24.
　本実施例に係る放射線モニタは、事前に放射線検出部１０近傍の温度測定値に対する光子１個１個の計数率を測定して記録しておくことで、放射線モニタで放射線を測定中に温度を測定し、温度の測定値からデータベースに記録されたデータを用いて熱放射（輻射）による計数率を導出できる。 The radiation monitor according to the present embodiment measures and records the counting rate of each photon for each temperature measurement value in the vicinity of the radiation detection unit 10 in advance, so that the temperature can be measured during radiation measurement by the radiation monitor. It is possible to derive the count rate due to thermal radiation (radiation) using the data recorded in the database from the measured value of the temperature measured.
　これにより、計数率の測定値から、熱放射による計数率を差分することで、放射線による計数率を導出し、事前に測定した線量率と計数率の比例係数を用いることで線量率に変換し、熱放射により生成された光子の影響を除いた線量率を算出することができる。 As a result, the count rate due to radiation is derived by subtracting the count rate due to thermal radiation from the count rate measurement value, and converted to a dose rate by using the proportional coefficient between the dose rate and the count rate measured in advance. , It is possible to calculate the dose rate excluding the effect of photons generated by thermal radiation.
　実施例３は、放射線モニタが、光照射装置、光照射制御装置、光分岐部、光分岐用光学フィルタを備える点が、実施例１とは異なる。なお、その他については実施例１と同様である。したがって、実施例１とは異なる部分について説明し、重複する部分については説明を省略する。 The third embodiment is different from the first embodiment in that the radiation monitor includes a light irradiation device, a light irradiation control device, a light branching unit, and a light branching optical filter. The other points are the same as in the first embodiment. Therefore, only the parts different from the first embodiment will be described, and the description of the overlapping parts will be omitted.
　図７は、本発明の実施例３に係る放射線モニタの構成図である。 FIG. 7 is a configuration diagram of a radiation monitor according to the third embodiment of the present invention.
　本実施例に係る放射線モニタ１は、光照射装置５０、光照射制御装置５１、光分岐部６０、光分岐用光学フィルタ６１、をさらに備える。 The radiation monitor 1 according to the present embodiment further includes a light irradiation device 50, a light irradiation control device 51, a light branching unit 60, and a light branching optical filter 61.
　光照射装置５０は、放射線モニタ１が正常に機能しているか否かの判定を行う際に用いられる半導体レーザである。なお、光照射装置５０としてＬＥＤ（Light Emitting Diode）を用いてもよい。光照射装置５０は、放射線検出素子１１の発光波長とは異なる波長の光を発するようになっている。 The light irradiation device 50 is a semiconductor laser used when determining whether or not the radiation monitor 1 is functioning normally. An LED (Light Emitting Diode) may be used as the light irradiation device 50. The light irradiation device 50 emits light having a wavelength different from the emission wavelength of the radiation detection element 11.
　光分岐部６０は、放射線検出部１０からの光を光照射装置５０及び光検出部７０に向けて分岐させる。 The light branching unit 60 branches the light from the radiation detection unit 10 toward the light irradiation device 50 and the light detection unit 70.
　光照射制御装置５１は、光照射装置５０の発光強度、及び、連続発光またはパルス発光の時のパルス長と発光周波数等を制御する装置であり、配線を介して光照射装置５０に接続されている。光照射制御装置５１は、図示はしないが、ＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）、各種インタフェース等の電子回路を含んで構成されている。そして、ＲＯＭに記憶されたプログラムを読み出してＲＡＭに展開し、ＣＰＵが各種処理を実行するようになっている。光照射制御装置５１が実行する処理については後記する。 The light irradiation control device 51 is a device that controls the light emission intensity of the light irradiation device 50, the pulse length and the light emission frequency during continuous light emission or pulse light emission, and is connected to the light irradiation device 50 via wiring. There is. Although not shown, the light irradiation control device 51 is configured to include electronic circuits such as a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read and expanded in the RAM, and the CPU executes various processes. The processing executed by the light irradiation control device 51 will be described later.
　放射線検出部１０は、光ファイバ及び光ファイバの後段に設置した光分岐部６０を通して、光照射装置５０及びに光検出部７０それぞれ接続される。 The radiation detection unit 10 is connected to the light irradiation device 50 and the light detection unit 70, respectively, through an optical fiber and an optical branching unit 60 installed in the subsequent stage of the optical fiber.
　次に、本実施例に係る放射線モニタの動作を説明する。 Next, the operation of the radiation monitor according to this embodiment will be described.
　光照射装置５０を用いて照射する光の波長を、放射線発光素子１１に光を照射することによって生成する光の波長と異なる波長に設定する。光照射装置５０で発光した光を、光ファイバ及び光分岐部６０を介して、放射線発光素子１１に照射すると、放射線発光素子１１は、照射された光の強度に比例した個数の光子が生成される。この生成された光子と、照射した光が放射線検出部１０内で反射及び散乱された光子が合わさって、光ファイバ及び光分岐部６０を介して、波長選択部に入射する。 The wavelength of the light irradiated using the light irradiation device 50 is set to a wavelength different from the wavelength of the light generated by irradiating the radiation light emitting element 11 with light. When the light emitted from the light irradiation device 50 is applied to the radiation emitting element 11 via the optical fiber and the light branching unit 60, the radiation emitting element 11 generates a number of photons proportional to the intensity of the applied light. It The generated photons and the photons reflected and scattered by the irradiated light in the radiation detection unit 10 are combined and enter the wavelength selection unit via the optical fiber and the optical branching unit 60.
　波長選択部では、放射線発光素子１１で発光した波長の光子のみが、光検出部７０に入射される。 In the wavelength selection unit, only photons of the wavelength emitted by the radiation emitting element 11 are incident on the photodetection unit 70.
　光検出部７０は、検出した光子を電気信号に変換する。 The light detection unit 70 converts the detected photons into an electric signal.
　測定装置８０は、光検出部７０から出力された電気信号の計数率を測定する。事前に測定した発光部からの光の強度と計数率の関係を用いて、放射線モニタの動作確認及び校正を行う。 The measuring device 80 measures the counting rate of the electric signal output from the photodetection unit 70. The operation of the radiation monitor is checked and calibrated by using the relationship between the intensity of light from the light emitting unit and the count rate measured in advance.
　放射線モニタ１００Ｇの点検時には、光照射装置５０の光強度や、電気パルスの計数率に基づいて、解析・表示装置９０が所定の処理を実行するようになっている。すなわち、解析・表示装置９０は、光照射装置５０が劣化したのか、それとも、他の部品（放射線検出素子１１や光ファイバ４０等）が劣化したのかを判定し、その判定結果を表示する。これにより、放射線モニタ１の信頼性を従来よりも高めることができる。 At the time of inspecting the radiation monitor 100G, the analysis / display device 90 executes a predetermined process based on the light intensity of the light irradiation device 50 and the count rate of electric pulses. That is, the analysis / display device 90 determines whether the light irradiation device 50 has deteriorated or other components (the radiation detection element 11, the optical fiber 40, etc.) have deteriorated, and displays the determination result. As a result, the reliability of the radiation monitor 1 can be increased more than ever before.
　実施例４は、放射線モニタの計数率の経時変化を校正する点が実施例２と異なる。なお、その他については実施例２と同様である。したがって、実施例２とは異なる部分について説明し、重複する部分については説明を省略する。 Example 4 is different from Example 2 in that the change over time of the count rate of the radiation monitor is calibrated. The other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
　図８に加熱部に与える電力に対する光子１個１個の計数率の経時変化の一例を示す。 Fig. 8 shows an example of changes over time in the counting rate of each photon with respect to the electric power applied to the heating unit.
　放射線モニタ１を放射線測定に使用する前に、電圧制御装置２３から加熱部２１に印加する電圧に対する光子１個１個の計数率のデータベースを作っていても、使用中に加熱部２１に与える電力に対する光子１個１個の計数率が変化する可能性がある。 Before the radiation monitor 1 is used for radiation measurement, even if the database of the counting rate of each photon with respect to the voltage applied to the heating unit 21 is made from the voltage control device 23, the power supplied to the heating unit 21 during use The count rate of each photon with respect to can vary.
　そこで本実施例では、例えば放射線モニタ１のメンテナンスをするときに、加熱部２１に印加する電圧を変化させたときの光子１個１個の計数率の測定値から、熱放射（輻射）が無いまたは非常に少ない電量の範囲における光子１個１個の計数率を差分することで、加熱部２１に印加する電圧を変化させたときの熱放射（輻射）による計数率を導出し、データベース２７に保存する。 Therefore, in the present embodiment, for example, when performing maintenance on the radiation monitor 1, there is no heat radiation (radiation) from the measured value of the count rate of each photon when the voltage applied to the heating unit 21 is changed. Alternatively, the count rate of heat radiation (radiation) when the voltage applied to the heating unit 21 is changed is derived by subtracting the count rate of each photon in the range of very small amount of electricity, and stored in the database 27. save.
　これにより、最新のデータベースをもとに、放射線による計数率を導出し、この計数率と、事前に測定した線量率と計数率の比例係数を用いることで線量率に変換することで、経時劣化した場合においても熱放射（輻射）による計数率を精度良く補正できる。 With this, the radiation count rate is derived based on the latest database, and this count rate and the dose rate measured in advance and the proportional coefficient of the count rate are used to convert the dose rate into a dose rate. Even in such a case, the counting rate due to thermal radiation can be accurately corrected.
　実施例５は、放射線検出部の計数率から放射線モニタが水中又は気中のいずれにあるかを判定する点が実施例２と異なる。なお、その他については実施例２と同様である。したがって、実施例２とは異なる部分について説明し、重複する部分については説明を省略する。 The fifth embodiment is different from the second embodiment in that it is determined from the count rate of the radiation detection unit whether the radiation monitor is in water or in the air. The other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
　図９に、放射線検出部１０が水中または気中にある場合の光子１個１個の計数率の時間変化と加熱部２１への電力印加の関係の一例を示す。 FIG. 9 shows an example of the relationship between the time change of the counting rate of each photon and the power application to the heating unit 21 when the radiation detection unit 10 is in water or in the air.
　本実施例では、事前に、放射線検出部１０を水中及び気中のそれぞれに設置した場合において、加熱部２１に電圧印加開始前、印加開始、印加中、印加停止及び印加停止後の光子１個１個の計数率の変化を測定し、データベース２７に保存しておく。 In the present embodiment, when the radiation detection unit 10 is installed in water and in the air in advance, one photon before the application of voltage to the heating unit 21, before application of voltage, during application, application stop, and application stop The change of one count rate is measured and stored in the database 27.
　加熱部２１に電力印加前、印加開始、印加中、印加停止及び印加停止後の光子１個１個の計数率の変化を測定した場合、放射線検出部１０が水中にある場合は、気中の場合と比較して、放射線検出部１０の周囲の熱伝達率が高いため、光子１個１個の計数率の上昇率が遅く、最大計数率も低くなる。また、印加停止後の計数率の下降率も遅くなる。 When the change in the counting rate of each photon before the application of power to the heating unit 21, before the application of the power, during the application of the power, after the application of the power is stopped, and when the application of the power is stopped, when the radiation detection unit 10 is in water, Compared to the case, the heat transfer rate around the radiation detection unit 10 is high, so the rate of increase of the count rate of each photon is slow and the maximum count rate is also low. Moreover, the rate of decrease of the count rate after the application is stopped also becomes slow.
　この光子１個１個の計数率の上昇率、最大計数率、及び、計数率の下降率の測定データと、事前に測定したデータベースをもとに、放射線検出部１０が水中または気中のいずれかの状態にあるかを判定できる。 Based on the measured data of the count rate increase rate, the maximum count rate, and the count rate decrease rate of each photon, and the database measured in advance, whether the radiation detection unit 10 is in water or in air. It can be determined whether or not.
　実施例６は、加熱部２１をレーザー加熱装置とする点が実施例２と異なる。 Example 6 differs from Example 2 in that the heating unit 21 is a laser heating device.
　図１０は、本発明の実施例６に係る放射線モニタの構成図である。 FIG. 10 is a configuration diagram of a radiation monitor according to the sixth embodiment of the present invention.
　本実施例では、加熱部２１としてレーザ加熱装置を用いる。レーザ加熱装置は、放射線検出部１０と光ファイバ４０で接続される。 In this embodiment, a laser heating device is used as the heating unit 21. The laser heating device is connected to the radiation detection unit 10 via an optical fiber 40.
　レーザ加熱装置で生成したレーザ光を、光ファイバ４０を通して放射線検出部１０に照射する。ここで、照射されるレーザ光が、放射線検出部１０と光分岐部７０を光学的に接続する光ファイバに入射しない構造とする。放射線検出部１０に照射するレーザ光の強度及びレーザ光の照射時間を変化させることで、放射線検出部１０の温度を変化させる。温度計側部２４は放射線検出部１０の近傍の温度を測定する。データベース２７は、温度計側部２４で測定した温度の測定値と、測定装置８０で測定される熱放射（輻射）による光子１個１個を変換した電気信号の計数率の関係を記録することで、事前に熱放射による放射線の計数率を記録しておく。 The laser light generated by the laser heating device is applied to the radiation detection unit 10 through the optical fiber 40. Here, the structure is such that the irradiated laser light does not enter the optical fiber that optically connects the radiation detection unit 10 and the light branching unit 70. The temperature of the radiation detection unit 10 is changed by changing the intensity of the laser light applied to the radiation detection unit 10 and the irradiation time of the laser light. The thermometer side part 24 measures the temperature in the vicinity of the radiation detection part 10. The database 27 records the relationship between the measured value of the temperature measured by the thermometer side part 24 and the count rate of the electric signal obtained by converting each photon by thermal radiation (radiation) measured by the measuring device 80. Then, record the count rate of radiation due to thermal radiation in advance.
　これにより、計数率の測定値から、熱放射による計数率を差分し、放射線による計数率を導出し、事前に測定した線量率と計数率の比例係数を用いることで線量率に変換し、熱放射により生成された光子の影響を除いた線量率を算出することができる。 As a result, the count rate due to thermal radiation is subtracted from the measured count rate, the count rate due to radiation is derived, and it is converted into a dose rate by using the proportional coefficient between the dose rate and the count rate measured in advance. The dose rate can be calculated without the effects of photons produced by the radiation.
　実施例７は、放射線検出部の構造が実施例６と異なる。なお、その他については実施例２と同様である。したがって、実施例２とは異なる部分について説明し、重複する部分については説明を省略する。 Example 7 differs from Example 6 in the structure of the radiation detection unit. The other points are the same as in the second embodiment. Therefore, only the parts different from the second embodiment will be described, and the description of the overlapping parts will be omitted.
　図１１は本発明の実施例７に係る放射線モニタの構成図、図１２は本発明の実施例７に係る放射線検出部の構成図である。 11 is a configuration diagram of a radiation monitor according to a seventh embodiment of the present invention, and FIG. 12 is a configuration diagram of a radiation detection unit according to the seventh embodiment of the present invention.
　本実施例では、光ファイバ４０に接続していない放射線発光素子１１の側面を、熱放射（輻射）率の小さい金属等で覆う。これを内面とする。また、放射線発光素子１１の側面を熱放射（輻射）率の小さい金属等の外側から熱放射（輻射）率の大きい物質で覆う。これを外面とする。なお、本実施例では、光ファイバ４０と接している放射線発光素子１１の面を底面、その他の面を側面と称する。 In this embodiment, the side surface of the radiation emitting element 11 that is not connected to the optical fiber 40 is covered with a metal or the like having a low heat radiation rate. This is the inside. In addition, the side surface of the radiation emitting element 11 is covered with a substance having a high heat emission (emissivity) from the outside such as a metal having a low heat emission (emissivity). This is the outer surface. In this embodiment, the surface of the radiation emitting element 11 that is in contact with the optical fiber 40 is called the bottom surface, and the other surfaces are called the side surfaces.
　放射線発光素子１１には、放射線発光素子１１が発光して生成する光子を光検出部７０に伝送するための光ファイバと、レーザ加熱装置（加熱部２１）で放射線発光素子１１を加熱するための光ファイバと、温度測定部２４で温度を測定するための光ファイバが接続される。 The radiation emitting element 11 has an optical fiber for transmitting photons generated by the radiation emitting element 11 to generate light, and a laser heating device (heating unit 21) for heating the radiation emitting element 11. The optical fiber and the optical fiber for measuring the temperature in the temperature measuring unit 24 are connected.
　加熱部２１であるレーザ加熱装置からのレーザ光を、放射線発光素子１１の外面に照射する。このとき、熱放射（輻射）率の大きい物質に照射することで、加熱効率が向上するとともに、熱放射（輻射）率の小さい金属等の内面による光の遮蔽により、外面からの熱放射（輻射）が放射線発光素子１１内に入り混まない。また、熱放射（輻射）率の小さい金属等の内面からの熱放射（輻射）は小さいことから、放射線測定における熱放射（輻射）のバックグラウンドを小さく抑えることができる。また、温度測定部２４は、放射線測定素子１１の外面からの熱放射（輻射）率を温度測定用光ファイバを通して測定する。熱放射（輻射）率の大きい既知の物質からの熱放射（輻射）強度を測定することで、精度良く温度を測定することが可能となる。 The laser light from the laser heating device which is the heating unit 21 is applied to the outer surface of the radiation emitting element 11. At this time, heating efficiency is improved by irradiating a substance having a high heat radiation rate, and the heat radiation from the outer surface (radiation rate) is improved by shielding the light from the inner surface of a metal having a low heat radiation rate. ) Does not mix in the radiation emitting element 11. Further, since the heat radiation (radiation) from the inner surface of a metal or the like having a low heat radiation (radiation) rate is small, the background of the heat radiation (radiation) in the radiation measurement can be suppressed to be small. Further, the temperature measuring unit 24 measures the heat radiation rate from the outer surface of the radiation measuring element 11 through the temperature measuring optical fiber. By measuring the heat radiation (radiation) intensity from a known substance having a high heat radiation (radiation) rate, it becomes possible to measure the temperature with high accuracy.
１０…放射線検出部、１１…放射線発光素子、１２…検出器ハウジング、２０…加熱装置、２１…加熱部、２２…電線、２３…電圧制御装置、２４…温度測定部、２５…信号線、２６…温度測定制御装置、２７…データベース、４０…光ファイバ、５０…光照射装置、５１…発光部制御装置、６０…光分岐部、６１…光分岐用光学フィルタ、７０…光検出部、８０…測定装置、９０…解析・表示装置
  DESCRIPTION OF SYMBOLS 10 ... Radiation detection part, 11 ... Radiation emitting element, 12 ... Detector housing, 20 ... Heating device, 21 ... Heating part, 22 ... Electric wire, 23 ... Voltage control device, 24 ... Temperature measuring part, 25 ... Signal line, 26 ... temperature measurement control device, 27 ... database, 40 ... optical fiber, 50 ... light irradiation device, 51 ... light emitting unit control device, 60 ... optical branching unit, 61 ... optical branching optical filter, 70 ... photodetecting unit, 80 ... Measuring device, 90 ... Analysis / display device

Claims (10)

  1. 　放射線が入射すると光子を生成して発光する放射線検出素子と、前記放射線検出素子を収容するハウジングとを有する放射線検出部と、
    　前記放射線検出部で生成された光子１個１個を電気信号に変換する光検出部と、
    　前記電気信号の計数率に基づいて、放射線の線量率を算出する測定装置と、
    　前記放射線検出部またはその近傍を加熱する加熱部と、
    　を備えた放射線モニタであって、
    　前記測定装置は、前記加熱部に電圧を印加したときに第１の計数率を算出し、前記放射線検出部に放射線が入射したときに第２の計数率を算出し、前記第２の計数率から前記第１の計数率を引いた第３の計数率を放射線の線量率に換算する
    　ことを特徴とする放射線モニタ。     A radiation detection unit having a radiation detection element that generates photons and emits light when radiation enters, and a radiation detection unit having a housing that houses the radiation detection element
    A photodetector for converting each photon generated by the radiation detector into an electric signal;
    Based on the count rate of the electrical signal, a measuring device for calculating the radiation dose rate,
    A heating unit for heating the radiation detection unit or its vicinity;
    A radiation monitor comprising:
    The measurement device calculates a first count rate when a voltage is applied to the heating section, calculates a second count rate when radiation enters the radiation detection section, and calculates the second count rate. A radiation monitor, wherein a third count rate obtained by subtracting the first count rate from the above is converted into a radiation dose rate.
  2. 　電圧を印加して前記加熱部の温度を変化させる電圧制御装置と、
    　前記加熱部に印加する電圧と前記第１の計数率の関係を記録するデータベースとを備える
    　ことを特徴とする請求項１に記載の放射線モニタ。     A voltage control device that applies a voltage to change the temperature of the heating unit,
    The radiation monitor according to claim 1, further comprising a database that records a relationship between the voltage applied to the heating unit and the first count rate.
  3. 　前記放射線検出部の近傍の温度を測定する温度測定部を備え、
    　前記温度測定部が測定した温度の測定値と前記第１の計数率の関係を記録するデータベースとを備える
    　ことを特徴とする請求項１または請求項２に記載の放射線モニタ。     A temperature measuring unit for measuring the temperature in the vicinity of the radiation detecting unit,
    The radiation monitor according to claim 1 or 2, further comprising: a database that records a relationship between the measured value of the temperature measured by the temperature measuring unit and the first count rate.
  4. 　前記測定装置は、前記加熱部に印加する電圧を０としたときの第４の計数率を算出し、
    前記データベースに記録された前記第１の計数率と前記第４の計数率の差分により、前記データベースに記録された前記加熱部に印加する電圧または前記温度測定部が測定した温度の測定値と前記第１の計数率との関係を校正する
    　ことを特徴とする請求項２または請求項３に記載の放射線モニタ。     The measurement device calculates a fourth count rate when the voltage applied to the heating unit is 0,
    According to the difference between the first count rate and the fourth count rate recorded in the database, the voltage applied to the heating section recorded in the database or the measured value of the temperature measured by the temperature measuring section and the The radiation monitor according to claim 2 or 3, wherein a relationship with the first count rate is calibrated.
  5. 　前記放射線発光素子が発光する光の波長と異なる波長の光を、前記放射線発光素子に照射する照射装置と、
    　前記照射装置に照射された光によって前記放射線発光素子が生成する波長の光を透過する波長選択フィルタを備える
    　ことを特徴とする請求項１乃至請求項４のいずれか一項に記載の放射線モニタ。     An irradiation device for irradiating the radiation emitting element with light having a wavelength different from the wavelength of light emitted by the radiation emitting element,
    The radiation monitor according to any one of claims 1 to 4, further comprising a wavelength selection filter that transmits light having a wavelength generated by the radiation emitting element by the light with which the irradiation device is irradiated.
  6. 　前記測定装置は、前記加熱部で加熱する前、加熱開始するとき、加熱中、加熱を停止するとき、加熱停止後の少なくともいずれかの光子１個１個の計数率の変化から、前記放射線検出部が気中にあるか、水中にあるかを判定する
    　ことを特徴とする請求項１乃至請求項５のいずれか一項に記載の放射線モニタ。     The measurement device is configured to detect the radiation from the change in the counting rate of at least one photon before heating in the heating unit, when starting heating, during heating, when stopping heating, and after stopping heating. The radiation monitor according to any one of claims 1 to 5, wherein it is determined whether the part is in the air or in the water.
  7. 　前記加熱部は、生成したレーザ光を光ファイバを通して前記放射線検出部に照射することで前記放射線検出部を加熱することを特徴とする請求項１乃至請求項６のいずれか一項に放射線モニタ。 The radiation monitor according to any one of claims 1 to 6, wherein the heating unit heats the radiation detection unit by irradiating the radiation detection unit with the generated laser light through an optical fiber.
  8. 　前記加熱部は、放射線検出部に照射するレーザ光の強度またはレーザ光の照射時間を変化させることで、前記放射線検出部の温度を変化させることを特徴とする請求項７に放射線モニタ。 The radiation monitor according to claim 7, wherein the heating unit changes the temperature of the radiation detection unit by changing the intensity of the laser light or the irradiation time of the laser light with which the radiation detection unit is irradiated.
  9. 　前記放射線発光素子は、側面を第１の熱放射率の金属で覆い、第１の熱放射率の金属の外側から第１の熱放射率よりも大きい第２の熱放射率の金属で覆うことを特徴とする請求項７または請求項８に記載の放射線モニタ。 The radiation emitting element has a side surface covered with a metal having a first thermal emissivity, and a metal having a second thermal emissivity larger than the first thermal emissivity from the outside of the metal having the first thermal emissivity. The radiation monitor according to claim 7 or 8, characterized in that.
  10. 　放射線発光素子に放射線が入射すると光子を生成して発光するステップと、
    　前記放射線検出部で生成された光子１個１個を電気信号に変換するステップと、
    　前記電気信号の計数率に基づいて、放射線の線量率を算出するステップと、
    　を備えた放射線の測定方法であって、
    　前記放射線発光素子が加熱されたときに第１の計数率を算出し、前記放射線発光素子に放射線が入射したときに第２の計数率を算出し、前記第２の計数率から前記第１の計数率を引いた第３の計数率を放射線の線量率に換算する
    　ことを特徴とする放射線の測定方法。
          Generating a photon and emitting light when radiation enters the radiation emitting element;
    Converting each photon generated by the radiation detection unit into an electric signal;
    Calculating a radiation dose rate based on the count rate of the electrical signal;
    A method of measuring radiation, comprising:
    A first count rate is calculated when the radiation emitting element is heated, a second count rate is calculated when radiation enters the radiation emitting element, and the first count rate is calculated from the second count rate. A method for measuring radiation, comprising converting a third count rate, which is a count rate, into a radiation dose rate.
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6093509A (en) * 1983-10-26 1985-05-25 Yaskawa Electric Mfg Co Ltd Input and output module of programmable controller
JPS61164177A (en) * 1985-01-16 1986-07-24 Rikagaku Kenkyusho Slow electron measuring instrument
JPS623684A (en) * 1985-06-29 1987-01-09 Hitachi Medical Corp Detector for x-ray ct equipment
JP2014211380A (en) * 2013-04-19 2014-11-13 三菱電機株式会社 Dose rate measurement device
JP2016114392A (en) * 2014-12-11 2016-06-23 株式会社日立製作所 Radiation monitor
JP2017110952A (en) * 2015-12-15 2017-06-22 株式会社日立製作所 Radiation detector and radiation detection method using the same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS623083U (en) * 1985-06-20 1987-01-09

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6093509A (en) * 1983-10-26 1985-05-25 Yaskawa Electric Mfg Co Ltd Input and output module of programmable controller
JPS61164177A (en) * 1985-01-16 1986-07-24 Rikagaku Kenkyusho Slow electron measuring instrument
JPS623684A (en) * 1985-06-29 1987-01-09 Hitachi Medical Corp Detector for x-ray ct equipment
JP2014211380A (en) * 2013-04-19 2014-11-13 三菱電機株式会社 Dose rate measurement device
JP2016114392A (en) * 2014-12-11 2016-06-23 株式会社日立製作所 Radiation monitor
JP2017110952A (en) * 2015-12-15 2017-06-22 株式会社日立製作所 Radiation detector and radiation detection method using the same

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