JP7195876B2 - Radiation monitor and radiation measurement method - Google Patents

Description

The present invention relates to a radiation monitor and a radiation measuring method for measuring a radiation dose rate.

Gas detectors, scintillation detectors, semiconductor detectors, and the like are known as conventional charged particle detectors.

A gas detector has a structure in which a metal wire is installed in a container filled with gas. Charged particles ionize the gas in the detector to produce electrons, which are amplified in a high electric field region near a metal wire and measured as an electrical signal.

A scintillation detector emits light when a charged particle is incident on the scintillation element, converts the emitted light into an electric signal using a photomultiplier tube or the like, and measures the charged particles based on the electric signal. When a charged particle is incident, a large number of photons are generated, and the number of generated photons is proportional to the energy of the incident charged particle. is measured to measure the energy of the incident charged particles.

In semiconductor detectors, electron-hole pairs generated by ionization by charged particles are generated in a region (depletion layer) where there are almost no electrons or holes, which is formed around the junction surface where p-type and n-type semiconductors are joined. , p-type and n-type detectors that detect charged particles based on the electrical signals generated by their migration. 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 particle. The energy of the incident charged particles is measured by measuring the crest value of the pulsed electrical signal.

JP 2017-15662 A JP 2016-114392 A

However, when these charged particle beam detectors are used in a high dose environment, there are the following problems.

In the case of a gas detector, a large number of gamma rays entering the gas detector and electrons due to Compton scattering with the gas and detector container material are measured, so it is difficult to distinguish them from charged particles.

In the case of a scintillation detector, a large number of gamma rays are incident on the scintillation element at the same time, and pulsed electrical signals are superimposed, making it difficult to accurately measure charged particles. If the surroundings of the scintillation element are covered with a radiation shielding material such as lead in order to prevent this, the charged particles cannot enter the detector, which makes the use difficult.

In the case of a semiconductor detector, a large number of gamma rays are incident on the semiconductor element at the same time, and the pulsed electrical signals are superimposed, making it difficult to accurately measure charged particles. In order to prevent this, if the periphery of the semiconductor element is covered with a radiation shielding material such as lead, the charged particles cannot enter the detector, making it difficult to use.

Similar to charged particle detectors, gas detectors, scintillation detectors, semiconductor detectors, and the like are known as detectors for detecting neutron beams. However, as with the above charged particle detector, it was difficult to measure in a high dose rate environment.

On the other hand, as a radiation monitor capable of measuring in a high dose rate environment, there are techniques described in Patent Document 1 and Patent Document 2, for example. These documents describe techniques for transmitting light emitted from a radiation detection element through an optical fiber and measuring the dose rate based on the count rate of each photon.

However, when a radiation monitor is used in a high-temperature environment, there is a background due to radiation, so a correction method is required. Although Patent Literature 1 describes a correction method using a plurality of wavelengths, a system for measuring each photon of a plurality of wavelengths is required, which complicates the system. Also, there is no description of a technique for confirming and evaluating changes in the background due to radiation due to deterioration of the radiation monitor during plant operation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation monitor capable of measuring the dose rate with high accuracy even in a high temperature and high dose rate environment.

In order to solve the above-mentioned problems, one representative aspect of the present invention is to provide "a radiation detection unit having a radiation detection element that generates photons and emits light when radiation is incident thereon, and a housing that accommodates the radiation detection element; A photodetector that converts each photon generated by the radiation detector into an electrical signal, a measuring device that calculates the dose rate of radiation based on the count rate of the electrical signal, and a radiation detector or its vicinity. a heating unit that heats, the measuring device calculates a first count rate when a voltage is applied to the heating unit, and calculates a second count rate when radiation is incident on the radiation detector. A radiation monitor characterized by calculating a count rate and converting a third count rate obtained by subtracting the first count rate from the second count rate into a dose rate of radiation."

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the radiation monitor which shows a correct dose rate also in a high temperature and high dose rate environment.

1 is a configuration diagram of a radiation monitor according to Example 1 of the present invention; FIG. FIG. 2 is an explanatory diagram of the relationship between the counting rate of each photon due to thermal radiation (radiation) and the wavelength of the photon; FIG. 5 is an explanatory diagram of the relationship between the counting rate of each photon and the power applied to the heating unit when the dose rate is constant. FIG. 4 is an explanatory diagram of a method of calculating a dose rate excluding the effects of photons generated by thermal radiation; FIG. 7 is a configuration diagram of a radiation monitor according to Example 2 of the present invention; An example of the photon-by-photon count rate for temperature measurements. FIG. 7 is a configuration diagram of a radiation monitor according to Example 3 of the present invention; FIG. 4 is an explanatory diagram of temporal changes in the counting rate of individual photons with respect to the power applied to the heating unit; FIG. 4 is an explanatory diagram of the relationship between the time change in the counting rate of each photon and the application of power to the heating section when the radiation light emitting element section is in water or in the air; FIG. 11 is a configuration diagram of a radiation monitor according to Example 6 of the present invention; FIG. 11 is a configuration diagram of a radiation monitor according to Example 7 of the present invention; FIG. 11 is a configuration diagram of a radiation detection unit according to Example 7 of the present invention;

Preferred examples for carrying out the present invention will be described below. It should be noted that the following is merely an example of implementation, and is not intended to limit the invention itself to the following specific contents.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3. FIG.

First, the configuration of the radiation monitor according to this embodiment will be described. FIG. 1 is a configuration diagram of a radiation monitor according to Embodiment 1 of the present invention.

The radiation monitor 1 according to the present embodiment includes a radiation detection unit 10 that emits light when radiation is incident, a heating device 20 that heats the radiation detection unit 10, an optical fiber 40, a light detection unit 70, a measurement device 80, An analysis/display device 90 is provided.

The radiation detection unit 10 includes a radiation light emitting element 11 made of a ceramic base material to which a rare earth element is added, and a detector housing 12 that accommodates the radiation light emitting element 11 . A radiation detection unit 10 is installed in a measurement area for measuring radiation.

The radiation light-emitting element 11 is formed of a light-transmitting material such as transparent yttrium, aluminum, and garnet as a ceramic base material, and rare earth elements such as ytterbium, neodymium, cerium, and praseodymium contained in the light-transmitting material. ing. The light decay time of the radiation light emitting element 11 (for example, yttrium aluminum garnet is YAG:Nd, which is a material containing neodymium) is long compared to NaI, BGO, and plastic scintillators used in conventional radiation detectors. choosing something.

The heating device 20 includes a heating section 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 section 21 .

The optical fiber 40 connects the radiation detector 10 and the photodetector 70 . More specifically, one end of the optical fiber 40 is connected to the radiation light emitting element 11 and the other end of the optical fiber 40 is connected to the photodetector 70 . Regarding the matter that the optical fiber 40 is “connected” to the radiation light emitting element 11 , in addition to the configuration in which one end of the optical fiber 40 is closely attached to the radiation light emitting element 11 , one end of the optical fiber 40 is connected to the radiation light emitting element 11 . Contiguous configurations are also included.

The photodetector 70 converts the light (pulse light) guided to itself via the optical fiber 40 into an electrical signal (photodetection process). More specifically, when one photon is incident on the photodetector 70, one electrical signal (pulse signal) is generated by photoelectric conversion. For example, a photomultiplier tube or a photodiode can be used as such a photodetector 70 .

The measuring device 80 is a device for measuring the count rate of the electrical signal input from the photodetector 70, and is connected to the photodetector 70 via the wiring k1. Although not shown, the measuring device 80 includes electronic circuits such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read out and developed in the RAM, and the CPU executes various processes.

The analysis/display device 90 is connected to the measurement device 80 via the wiring k2. Although not shown, it includes electronic circuits such as a CPU, ROM, RAM, and various interfaces. The analysis/display device 90 calculates the radiation dose rate (analysis processing) based on the count rate of the electrical signal input from the measurement device 80, and displays the calculation result. The electrical signal count rate and the radiation dose rate are in a proportional relationship, and the proportionality coefficient is stored in advance in the analysis/display device 90 .

Next, the measurement principle and operation of the radiation monitor according to this embodiment will be described.

It is known that the dose rate of radiation incident on the radiation detection element 11 and the number of photons generated per unit time by the radiation detection element 11 are in a proportional relationship. That is, the dose rate of radiation incident on the radiation detection element 11 and the count rate of the electrical signal (pulse signal) converted by the photodetector 70 are in a proportional relationship. Therefore, in the present embodiment, based on such a proportional relationship, the number of electrical signals per unit time (counting rate) output from the photodetector 70 to the measuring device 80 is converted into a dose rate of radiation, and the dose Calculate the rate. A detailed description will be given below.

When radiation or light is incident on the radiation light emitting element 11, electrons or rare earth atoms in the radiation light emitting element 11 transition to an excited state with a high energy level. A photon is generated when it transitions from its higher excited state to a lower energy level excited state or ground state.

Photons generated by the radiation emitting element 11 pass through the optical fiber 40 and are detected by the photodetector 70 . The photodetector 70 detects each photon and converts it into an electrical signal (pulse signal).

Note that when the number of photons (total number) generated per unit time by the radiation detecting element 11 exceeds the upper limit of photoelectric conversion in the photodetector 70, that is, when the photodetector 70 has a large number of photons. An additional optical attenuation filter (not shown) may be provided if incident and converts multiple photons into a single electrical signal. For example, a light attenuation filter may be provided in front of the photodetector 70 . Also, the type of the radiation detection element 11 and the material and thickness of the housing 12 may be appropriately selected so that the light attenuation filter is not required. Thus, each photon incident on the photodetector 70 can be converted into each electrical signal.

Further, by installing a wavelength selection section in front of the photodetection section 70, it becomes possible to transmit photons of only a specific wavelength. One or a plurality of wavelength selection filters may be used in the wavelength selection section, or a spectroscope may be used.

After being converted into an electric signal by the photodetector 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 electrical signal. The analysis and display device 90 derives the dose rate from the count rate using the pre-measured dose rate and count rate proportional coefficients.

Here, when the temperature of the environment in which the radiation detection unit 10 is installed rises, photons are generated by thermal radiation (radiation) from constituent members of the radiation detection unit 10 . FIG. 2 is an explanatory diagram of the relationship between the counting rate of each photon due to thermal radiation (radiation) and the wavelength of the photon. The figure also shows light emitted by radiation. The generation rate of photons due to thermal radiation (radiation) increases as the temperature of the installation environment increases, and increases as the wavelength of the photons increases. As the temperature of the installation environment increases, the background of photons due to thermal radiation (radiation) increases, making it impossible to accurately measure photons of wavelengths 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 (radiation).

Therefore, the radiation monitor according to this embodiment derives the count rate excluding the effect of photons generated by thermal radiation by the method described below.

First, the heating unit 21 heats the radiation detection unit 10 . At this time, photons are generated from the radiation detection section 10 according to the voltage applied to the heating section 21 by the voltage control device 23 . The photodetector 70 detects the generated photons and converts them into electrical signals. A measuring device 80 measures the count rate of the converted electrical signal.

FIG. 3 is an explanatory diagram of the relationship between the counting rate of each photon and the power applied to the heating unit 21 when the dose rate of radiation is constant. The generation rate of photons by 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 power applied to the heating unit 21 . When heated, the photon counting rate that changes according to changes in the applied power from the voltage control device 23 is, for example, as shown in FIG. The relationship between the photon counting 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, for example, in the analysis display device 90, and is used to obtain the measured value. is corrected as follows.

FIG. 4 is an explanatory diagram of a method of calculating a dose rate excluding the effect of photons generated by thermal radiation when actually measured in a radiation environment and a high temperature environment. Measurements of the count rate in a radiation and high temperature environment include the count rate due to radiation and the count rate due to thermal radiation. Therefore, the analysis display device 90 derives the count rate due to radiation by subtracting the count rate due to thermal radiation from the measured value of the count rate. Here, a value stored in advance or input using an external input device (not shown) or the like is used as the counting rate due to thermal radiation. Then, by using the dose rate measured in advance and the proportionality coefficient of the count rate, the dose rate can be converted to the dose rate, and the dose rate can be calculated without the influence of photons generated by thermal radiation.

Figure 4 shows the case where the count rate due to radiation is constant, but similarly, when the count rate due to radiation changes, the count rate due to thermal radiation (radiation) is subtracted from the count rate under radiation and high temperature environments. By doing so, it is possible to measure the count rate due to radiation and calculate the dose rate excluding the effect of photons generated by thermal radiation.

Example 2 differs from Example 1 in that the radiation monitor includes a thermometer side portion, a signal line, a temperature measurement control device, and a database. The present embodiment differs from the first embodiment in that, before the radiation monitor is used to measure radiation, the count rate of each photon with respect to the measured temperature is measured and recorded in the database. Others are the same as those of the first embodiment. Therefore, the parts different from the first embodiment will be explained, and the explanation of the overlapping parts will be omitted.

FIG. 5 is a configuration diagram of a radiation monitor according to Embodiment 2 of the present invention.

The radiation monitor 1 according to this embodiment further includes a thermometer side portion 24 , a signal line 25 , a temperature measurement control device 26 and a database 27 .

The temperature measurement unit 24 is a sensor or the like that measures temperature, and is installed near the radiation detection unit 10 . The installation position may be inside the housing 12 or outside the housing 12 . The temperature measured by the temperature measurement section 24 is transmitted to the temperature measurement control device 26 through the signal line 25 connecting the thermometer side portion 24 and the temperature measurement control device 26 .

The database 27 records the relationship between the measured temperature measured by the thermometer side 24 and the count rate of the electrical signal obtained by converting each photon due to thermal radiation (radiation) measured by the measuring device 80 .

FIG. 6 shows an example of the photon count rate for each measured temperature value.

Before the radiation monitor 1 is used for radiation measurement, the heating unit 21 is used to heat the radiation detection unit 10 . The voltage control device 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 near the radiation detection unit 10 or the heating unit 21 .

As the measured value of the temperature in the vicinity of the radiation detection part 10 or the heating part 21 measured by the thermometer side part 24 increases, the electricity generated by converting each photon due to thermal radiation (radiation) measured by the measuring device 80 Signal count rate increases.

The database 27 records the photon-by-photon count rate for the temperature measurements taken at the thermometer side 24 .

The radiation monitor according to this embodiment measures and records the counting rate of each photon with respect to the temperature measurement value in the vicinity of the radiation detection unit 10 in advance. The count rate due to thermal radiation (radiation) can be derived using the data recorded in the database from the temperature measurements.

As a result, by subtracting the count rate due to thermal radiation from the measured count rate, the count rate due to radiation is derived, and the dose rate measured in advance and the proportional coefficient of the count rate are used to convert to the dose rate. , the dose rate can be calculated excluding the effect of photons generated by thermal radiation.

The third embodiment differs from the first embodiment in that the radiation monitor includes a light irradiation device, a light irradiation control device, a light branching section, and a light branching optical filter. Others are the same as those of the first embodiment. Therefore, the parts different from the first embodiment will be explained, and the explanation of the overlapping parts will be omitted.

FIG. 7 is a configuration diagram of a radiation monitor according to Example 3 of the present invention.

The radiation monitor 1 according to this embodiment further includes a light irradiation device 50 , a light irradiation control device 51 , a light branching section 60 , and a light branching optical filter 61 .

The light irradiation device 50 is a semiconductor laser used when determining whether the radiation monitor 1 is functioning normally. Note that 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 .

The light splitter 60 splits the light from the radiation detector 10 toward the light irradiation device 50 and the light detector 70 .

The light irradiation control device 51 is a device for controlling the light emission intensity of the light irradiation device 50, and the pulse length and light emission frequency at the time of 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 includes electronic circuits such as a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and various interfaces. Then, the program stored in the ROM is read out and developed in the RAM, and the CPU executes various processes. Processing executed by the light irradiation control device 51 will be described later.

The radiation detection unit 10 is connected to the light irradiation device 50 and the light detection unit 70 through an optical fiber and a light branching unit 60 installed downstream of the optical fiber.

Next, the operation of the radiation monitor according to this embodiment will be described.

The wavelength of light to be irradiated using the light irradiation device 50 is set to a wavelength different from the wavelength of light generated by irradiating the radiation light emitting element 11 with light. When the radiation light emitting element 11 is irradiated with the light emitted by the light irradiation device 50 through the optical fiber and the light branching unit 60, the radiation light emitting element 11 generates photons in a number proportional to the intensity of the irradiated light. be. The generated photons and the photons reflected and scattered in the radiation detection section 10 from the irradiated light are combined and enter the wavelength selection section via the optical fiber and the light branching section 60 .

In the wavelength selection section, only photons of the wavelength emitted by the radiation light emitting element 11 are incident on the photodetection section 70 .

The photodetector 70 converts the detected photons into electrical signals.

The measuring device 80 measures the count rate of the electrical signal output from the photodetector 70 . Operation check and calibration of the radiation monitor are performed using the relationship between the light intensity from the light emitting unit and the counting rate measured in advance.

During inspection of the radiation monitor 100G, the analyzing/displaying device 90 executes predetermined processing based on the light intensity of the light irradiation device 50 and the counting rate of the electric pulse. That is, the analysis/display device 90 determines whether the light irradiation device 50 has deteriorated or other components (radiation detection element 11, optical fiber 40, etc.) and displays the determination result. Thereby, the reliability of the radiation monitor 1 can be improved more than before.

Example 4 differs from Example 2 in that the counting rate of the radiation monitor is calibrated over time. Others are the same as those of the second embodiment. Therefore, the parts different from the second embodiment will be explained, and the explanation of the overlapping parts will be omitted.

FIG. 8 shows an example of temporal changes in the counting rate of individual photons with respect to the power supplied to the heating unit.

Even if a photon-by-photon count rate database for the voltage applied to the heating unit 21 from the voltage controller 23 is created before the radiation monitor 1 is used for radiation measurement, the power supplied to the heating unit 21 during use The photon-by-photon count rate for a can vary.

Therefore, in this embodiment, for example, when performing maintenance of the radiation monitor 1, the measured value of the counting rate of each photon when the voltage applied to the heating unit 21 is changed shows that there is no thermal radiation (radiation). Alternatively, by subtracting the count rate of each photon in the range of very small amount of electricity, the count rate due to thermal radiation (radiation) when changing the voltage applied to the heating unit 21 is derived, and stored in the database 27 save.

As a result, based on the latest database, the count rate due to radiation is derived, and by using this count rate and the dose rate measured in advance and the proportional coefficient between the count rate and converting it into a dose rate, deterioration over time can be achieved. Even in this case, the count rate due to thermal radiation (radiation) can be accurately corrected.

The fifth embodiment differs from the second embodiment in that whether the radiation monitor is in water or in the air is determined from the count rate of the radiation detection unit. Others are the same as those of the second embodiment. Therefore, the parts different from the second embodiment will be explained, and the explanation of the overlapping parts will be omitted.

FIG. 9 shows an example of the relationship between the time change in 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 air.

In this embodiment, when the radiation detection unit 10 is installed in advance in water and in the air, one photon before the start of voltage application to the heating unit 21, the start of voltage application, the voltage application during the voltage application, and the voltage after the voltage application is stopped. A single counting rate change is measured and stored in the database 27 .

When the change in the counting rate of each photon before application of power to the heating unit 21, start of application, during application, stop of application, and after stop of application of power is measured, if the radiation detection unit 10 is in water, Since the heat transfer coefficient around the radiation detection unit 10 is higher than in the case, the rate of increase in the counting rate of each photon is slow, and the maximum counting rate is also low. Also, the rate of decrease in the counting rate after stopping the application is slowed down.

Based on the measurement data of the increase rate of the count rate of each photon, the maximum count rate, and the decrease rate of the count rate, and the database measured in advance, the radiation detection unit 10 can detect whether the radiation detection unit 10 is in water or in the air. It can be determined whether the state is

The sixth embodiment differs from the second embodiment in that the heating unit 21 is a laser heating device.

FIG. 10 is a configuration diagram of a radiation monitor according to Example 6 of the present invention.

In this embodiment, a laser heating device is used as the heating unit 21 . The laser heating device is connected to the radiation detector 10 by an optical fiber 40 .

A laser beam generated by a laser heating device is applied to the radiation detector 10 through the optical fiber 40 . Here, a structure is adopted in which the irradiated laser light does not enter the optical fiber that optically connects the radiation detection section 10 and the optical branching section 70 . The temperature of the radiation detecting section 10 is changed by changing the intensity of the laser light with which the radiation detecting section 10 is irradiated 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 24 and the count rate of the electrical signal obtained by converting each photon due to thermal radiation (radiation) measured by the measuring device 80. Then, record the radiation count rate due to thermal radiation in advance.

As a result, the count rate due to thermal radiation is subtracted from the measured count rate to derive the count rate due to radiation. A dose rate can be calculated that excludes the effects of photons produced by the radiation.

Example 7 differs from Example 6 in the structure of the radiation detection unit. Others are the same as those of the second embodiment. Therefore, the parts different from the second embodiment will be explained, and the explanation of the overlapping parts will be omitted.

FIG. 11 is a configuration diagram of a radiation monitor according to Embodiment 7 of the present invention, and FIG. 12 is a configuration diagram of a radiation detector according to Embodiment 7 of the present invention.

In this embodiment, the side surface of the radiation emitting element 11 that is not connected to the optical fiber 40 is covered with metal or the like having a low thermal radiation (emissivity) rate. Let this be the inner surface. Moreover, the side surface of the radiation light emitting element 11 is covered with a material having a high thermal radiation (radiation) rate, such as a metal having a low thermal radiation (radiation) rate. Let this be 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 side surfaces.

The radiation light emitting element 11 includes an optical fiber for transmitting photons generated by the radiation light emitting element 11 to the light detection unit 70, and a laser heating device (heating unit 21) for heating the radiation light emitting element 11. An optical fiber is connected to the optical fiber for temperature measurement by the temperature measurement unit 24 .

The outer surface of the radiation light emitting element 11 is irradiated with laser light from a laser heating device, which is the heating unit 21 . At this time, by irradiating a substance with a high thermal radiation (radiation) rate, the heating efficiency is improved, and the light is shielded by the inner surface of a metal with a low thermal radiation (radiation) rate, so that the thermal radiation (radiation) from the outer surface ) does not enter the radiation emitting element 11 . In addition, since the thermal radiation (radiation) from the inner surface of a metal or the like having a low thermal radiation (radiation) rate is small, the background of thermal radiation (radiation) in radiation measurement can be kept small. Also, the temperature measurement unit 24 measures the thermal radiation (emissivity) rate from the outer surface of the radiation measurement element 11 through the temperature measurement optical fiber. By measuring the thermal radiation (radiation) intensity from a known substance having a high thermal radiation (radiation) rate, it is possible to measure the temperature with high accuracy.

DESCRIPTION OF SYMBOLS 10... Radiation detection part 11... Radiation light-emitting element 12... Detector housing 20... Heating device 21... Heating part 22... Electric wire 23... Voltage control device 24... Temperature measurement 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 ... Light branching unit 61 ... Optical filter for light branching 70 ... Light detection unit 80 ... measuring device, 90... analysis/display device

Claims (10)

a radiation detection unit having a radiation detection element that generates photons and emits light when radiation is incident thereon; and a housing that houses the radiation detection element;
a photodetector that converts each photon generated by the radiation detector into an electrical signal;
a measuring device that calculates a dose rate of radiation based on the count rate of the electrical signal;
a heating unit that heats the radiation detection unit ;
A radiation monitor comprising:
The measurement device calculates a first count rate when a voltage is applied to the heating unit, calculates a second count rate when radiation is incident on the radiation detection unit, and calculates the second count rate. A radiation monitor, wherein a third counting rate obtained by subtracting the first counting rate from is converted into a dose rate of radiation. 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 counting rate. A temperature measurement unit that measures the temperature of the radiation detection unit ,
3. The radiation monitor according to claim 1, further comprising a database that records a relationship between the measured temperature measured by the temperature measuring unit and the first counting rate. The measuring device calculates a fourth count rate when the voltage applied to the heating unit is 0,
According to the difference between the first counting rate and the fourth counting rate recorded in the database, the voltage applied to the heating unit recorded in the database or the measured value of the temperature measured by the temperature measuring unit and the 4. The radiation monitor according to claim 3, wherein the relationship with the first count rate is calibrated. an irradiation device for irradiating the radiation light emitting element with light having a wavelength different from that of the light emitted by the radiation light emitting element;
5. 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 light emitting element by the light irradiated to the irradiation device. The measuring device detects the radiation from a change in the counting rate of at least one photon before heating, when heating is started, during heating, when heating is stopped, and after heating is stopped. 6. The radiation monitor according to any one of claims 1 to 5, wherein it is determined whether the part is in air or in water. 7. The radiation monitor according to claim 1, wherein the heating section heats the radiation detection section by irradiating the radiation detection section with the generated laser light through an optical fiber. 8. The radiation monitor according to claim 7, wherein the heating section changes the temperature of the radiation detection section by changing the intensity of the laser light irradiated to the radiation detection section or the irradiation time of the laser light. The radiation light-emitting element is covered with a metal having a first thermal emissivity on its side surface and covered with a metal having a second thermal emissivity higher than the first thermal emissivity from the outside of the metal with the first thermal emissivity. 9. The radiation monitor according to claim 7 or 8, characterized by: generating and emitting photons when radiation is incident on the radiation-emitting device;
converting each photon generated by the radiation emitting element into an electrical signal;
calculating a dose rate of radiation based on the count rate of the electrical signal;
A radiation measurement method comprising
A first count rate is calculated when the radiation light emitting element is heated, a second count rate is calculated when the radiation is incident on the radiation light emitting element, and the first count rate is calculated from the second count rate. A method of measuring radiation, characterized by converting a third counting rate obtained by subtracting the counting rate into a dose rate of radiation.

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