JP2942727B2 - Optical fiber radiation monitor system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to radiation for measuring or monitoring radiation dose (radiation dose rate) and radioactivity concentration in a nuclear power plant, a spent fuel reprocessing facility or a facility handling radioactive materials. More particularly, the present invention relates to an optical fiber radiation monitoring system capable of effectively performing data processing, calibration, inspection, correction, and the like.

[0002]

2. Description of the Related Art FIG. 14 shows a conventional example of a radiation monitor system.
It will be explained by. In this system, a plurality of detection units 1 including a radiation sensor and an electronic circuit are connected to a metal cable 2.
Are connected to the multiplexer 3. The multiplexing device 3 multiplexes information from the detection unit 1 and transmits a signal to the data processing device 5 through the optical fiber 4. In some cases, a metal cable is used instead of the optical fiber 4. In the conventional system, the data processing device 5 separates the multiplexed signal into signals corresponding to the individual detection units 1, and performs processing such as conversion to an engineering unit system, determination of a value, and sounding of an accompanying alarm. It is supposed to do.

In such a type of radiation monitor system, as a general method and procedure for calibrating the sensitivity of the radiation sensor, the detection unit 1 is removed, and
As shown in the figure, it is arranged around a calibration source 6 forming a standard irradiation field, and irradiates under a known radiation level.
The information from the detection unit 1 is transmitted as a signal to the data processing device 5 and the like via the metal cable 2, whereby the sensitivity and the like are calibrated.

[0004]

In the above-described conventional radiation monitoring system, relatively strong light is transmitted. The detection unit 1 in which the sensor and the electronic circuit are integrated is removed, and calibration is performed by itself. It was possible to do.

On the other hand, the present inventors have proposed a new concept of an optical fiber radiation monitor system in which passive optical radiation sensors are connected by optical fibers.
This system includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is extracted and transmitted to a data processing device. The radiation measurement system obtains information on the position of the radiation sensor and the intensity of radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent from the radiation sensor. Then, the measurement data can be observed as a superposition of data of a plurality of radiation sensors. In this system, weak light is transmitted, and transmission loss in the optical fiber and connection loss of each part also contribute to the performance.Therefore, it is meaningful to remove and calibrate the conventional detector. Will not have.

That is, there is no known existing measuring method, calibration method, procedure, function for the measuring device, and a system including these. Therefore, in such an optical fiber radiation monitoring system,
There is a demand for a new method according to the principle and characteristics.
In addition, since the quantification method and the data processing method during normal operation vary depending on the calibration method, it is necessary to similarly develop an inspection and correction method during operation after calibration of this monitor system.

The present invention has been made based on such circumstances, and not only the relative measurement of the radiation level, but also the operation of calibration, inspection, correction, etc. as a system for deriving the radiation dose (rate) and the radioactivity concentration. It is an object of the present invention to provide an optical fiber radiation monitoring system capable of securing stability against temperature change, deriving an ambient temperature, and realizing use in a high temperature environment.

[0008]

In order to achieve the above object, an optical fiber radiation monitoring system according to the present invention comprises a radiation sensor having a light entrance and exit through two or more optical fiber connectors. By connecting an optical fiber to this radiation sensor, taking out the light generated by the incidence of the radiation and transmitting it to the data processing device, and measuring the arrival time difference distribution of the light pulses sent simultaneously from the radiation sensor, In the optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of the radiation, when the measurement data is observed as a superposition of data of a plurality of radiation sensors, an area including a peak corresponding to each radiation sensor The net count value or peak count value is calculated at the start and end points of the effective section of the peak of the waveform to be measured. The large waveform values either in the form values integrated by subtracting the waveform in the effective period of said peak,
It is characterized by deriving radiation dose or radioactivity concentration.

According to the present invention, as the data processing section, a peak effective section is set for each peak corresponding to each radiation sensor in the arrival time difference distribution, and a coefficient of the section is set.
Include the function of calculating the peak net count or peak height by addition, subtraction, multiplication, and division by the measured count value, and converting it to the measurement time, radiation intensity or radioactivity concentration, or engineering unit conversion using an equation, etc. Thus, information corresponding to each radiation sensor can be extracted based on one arrival time difference distribution.

An optical fiber radiation monitoring system according to a second aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, when the measurement data is observed as a superposition of data of a plurality of radiation sensors, the coefficient of each function is determined by regression calculation as a function type superposition adapted to the distribution of arrival time difference of each radiation sensor. , Adding the measurement time to the information obtained from this function, There, is characterized in that for deriving the radiation dose or radioactive concentration.

According to the present invention, as the data processing section, the entire arrival time difference distribution is considered to be represented by a function type superimposition expressing each peak corresponding to each radiation sensor,
Determine the unknown coefficients of these functions by the least squares method, etc.
Include the function of deriving the peak net count or peak height based on the determined function and converting them into engineering units using measurement time, radiation intensity or conversion factor to radiation concentration or formula etc. Thus, information corresponding to each sensor can be extracted from one arrival time difference distribution.

According to a third aspect of the present invention, there is provided an optical fiber radiation monitoring system including a radiation sensor having a light entrance and exit through two or more optical fiber connectors. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, when the measurement data is observed as a superposition of the data of a plurality of sensors, the individual arrival time difference distribution of each of the radiation sensors acquired under constant irradiation conditions is prepared in advance, and these are multiplied by a coefficient. Determine the coefficient to be multiplied with each distribution by regression calculation Consideration between, based on radiation or information of radioactivity at the time of irradiation with the factor, and is characterized in that to derive a final radiation doses or radioactive concentration.

According to the present invention, the data processing unit considers that the entire arrival time difference distribution is represented by a superposition of the individual arrival time difference distributions corresponding to each radiation sensor multiplied by a factor, and By including the function of determining unknown coefficients by the least square method or the like, and converting the determined coefficients to engineering units using conversion coefficients or formulas for measuring time, radiation intensity or radioactivity concentration, 1 Information corresponding to each sensor can be extracted from the two arrival time difference distributions.

An optical fiber radiation monitoring system according to a fourth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In a monitor system, in order to check the operation of the radiation sensor, with the radiation sensor group connected by an optical fiber, light having a known intensity or spectrum is transmitted from one end of the optical fiber, and the transmission intensity is transmitted at the other end. Or measure the spectrum to determine the optical loss value for the transmitted light wavelength, By comparing the measured values, and is characterized in carrying out the optical state or operation check of the measuring system.

According to the present invention, a light source for inspection is connected to one end of an optical fiber to which a radiation sensor has been connected in advance. In this case, a light source of a monochromatic light source, a white light source or a light source of a specific wavelength band can be used as a light source, and a pulse light or a continuous (CW) light can be used as a lighting method. The other end of the optical fiber is connected to a photodetector suitable for the input light and its signal processing device. This allows
By observing the spectrum or intensity of the transmitted light and comparing it to previously measured data as needed, inspection and confirmation of the optical operation and soundness of the sensor and optical fiber can be performed.

An optical fiber radiation monitoring system according to a fifth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In a monitor system, in order to check the operation of the radiation sensor, pulsed light is incident from one end of the optical fiber while the group of radiation sensors is connected by an optical fiber, and the Rayleigh scattering and Fresnel reflection at the same end. The temporal change in light intensity is measured by the post-scattered light method, and the incident light wavelength In addition to measuring the transmission loss value of the optical fiber and the insertion loss or connection loss of the optical sensor, the optical state or operation of the system is checked by checking the fiber for cuts, bends, stresses, abnormalities of the sensor connector, etc. Is performed.

In the present invention, a Rayleigh scattering OTD for inspection is provided at one end of an optical fiber to which a radiation sensor is connected in advance.
R type (Optical Time Domain Re
An optical fiber reflectometer is connected. In this case, the light source is preferably as close as possible to the fluorescence wavelength emitted from the radiation sensor. The other end of the optical fiber can be left open. By observing the backscattered light with an optical fiber reflectometer and comparing it with previously measured data as needed, it is possible to check and confirm the optical operation and soundness of the radiation sensor and the optical fiber.

An optical fiber radiation monitoring system according to a sixth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In a monitor system, with the optical fiber actually used and the radiation sensor connected, consider the entire system as one measurement system, and then calibrate the individual radiation sensors individually or simultaneously to multiple radiation sensors. The calibration is performed by a procedure of irradiating radiation from a radiation source.

The present invention is particularly effective as a system in the case where the entire apparatus is a short, compact, small-scale temporary monitor apparatus, etc., and all the radiation sensors connected to the system as one system in advance are all optical. A mechanism and a jig that can be wound with a diameter greater than the allowable bending radius of the optical fiber if necessary, and a standard irradiation field or a radiation source with a known radioactivity concentration The calibration can be performed under the same conditions as the actual operating conditions by performing the irradiation calibration by using.

An optical fiber radiation monitoring system according to a seventh aspect of the present invention is provided with a radiation sensor having a light entrance and exit through two or more optical fiber connectors. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitoring system, a radiation sensor to be inspected is connected to a test optical fiber of a system that includes a variable optical attenuator that simulates the optical transmission loss value, and the radiation sensor alone is irradiated with radiation from a calibration source. It is characterized in that calibration is performed by performing the following.

According to the present invention, it is assumed that calibration is performed by removing individual sensors. In the original measurement system, an optical fiber or another sensor group interposed between the radiation sensor and the photodetector is used. A variable optical attenuator capable of simulating transmission / connection loss is interposed between the radiation sensor and the photodetector. In that state, by performing irradiation calibration using a standard irradiation field etc. or a radiation source whose radioactivity concentration is known,
Calibration can be performed under the same conditions as actual operating conditions.

An optical fiber radiation monitoring system according to an eighth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In a monitor system, a peak corresponding to each radiation sensor with respect to data measured for calibration under a condition of a known radiation dose or a radioactivity concentration of an individual radiation sensor in the calibration system according to claim 7 or 8. Net count value or peak count value in the area containing I asked directly I, taking into account the measurement time,
It is characterized in that a conversion method to this value and a radiation dose or a radioactivity concentration is derived and stored.

According to the present invention, as a data processing section for calibration, a peak effective section is set for each peak corresponding to each sensor in the arrival time difference distribution, and gross counting, peak net time, or The peak height is calculated by addition, subtraction, multiplication, and division of the measured count value, and using this, the measurement time, and the known radiation dose (rate) or radioactivity concentration, derives a conversion factor or formula for the radiation dose (rate) or radioactivity concentration. Then, by storing the information, a quantitative measurement can be performed.

An optical fiber radiation monitoring system according to a ninth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. 9. A monitor system according to claim 7, wherein said radiation sensors correspond to known radiation doses of individual radiation sensors in the calibration system according to claim 7 or data measured for calibration under radioactivity concentration conditions. Find the fit function of the time difference distribution, take the measurement time into account, There are those characterized by deriving and storing the conversion process to the radioactive concentration.

According to the present invention, it is assumed that the measurement data is observed as a superposition of data of a plurality of radiation sensors as the calibration data processing unit, and a function type adapted to the distribution of arrival time differences of the radiation sensors is calculated by regression. By determining each coefficient, using the information and measurement time obtained from this function, the known radiation dose or radioactivity concentration, deriving and storing the conversion factor and formula to the radiation dose or radioactivity concentration, , Quantitative measurement becomes possible.

An optical fiber radiation monitoring system according to a tenth aspect of the present invention is provided with a radiation sensor having a light entrance and exit through two or more optical fiber connectors. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In a monitoring system, with a single radiation sensor in the system according to claim 8, a distribution of arrival time differences measured for calibration under a condition of a known radiation dose or a radioactivity concentration for each radiation sensor, It is important to memorize the measurement time, radiation dose or radioactivity concentration corresponding to this distribution. It is an butterfly.

According to the present invention, as the calibration data processing unit, it is assumed that the measurement data is observed as a superposition of data of a plurality of radiation sensors, and the arrival time difference distribution of each radiation sensor is measured. Using a time, a known radiation dose or a radioactivity concentration, and deriving and storing a radiation dose or a radioactivity concentration conversion coefficient or expression, a quantitative measurement becomes possible.

An optical fiber radiation monitoring system according to an eleventh aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, the optical change of each radiation sensor and the optical fiber is identified from the change of the signal count value or the signal light intensity by the pulse light source according to claim 4, and the light pulser count value or the light intensity obtained in advance is determined. The feature is to correct the sensitivity of the radiation sensor based on the correlation with the sensitivity. It is an.

According to the present invention, light from the pulse light source mounted on the radiation sensor unit is temporarily radiated during operation,
By comparing the count value, light intensity, etc. when this was detected by the light detection unit with the previous measurement value, the light loss change of the system was identified, and the correlation between the pulse light source data and the sensitivity obtained in advance was determined. By correcting the sensitivity from the data that is represented, it is possible to correct a change in sensitivity over time.

An optical fiber radiation monitoring system according to a twelfth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, the change in the optical loss of the entire system due to the transmitted light according to claim 5 is measured, and based on the correlation between the optical loss value of the entire system and the counting sensitivity of each radiation sensor determined in advance, The sensitivity of each radiation sensor is corrected.

According to the present invention, during operation, the light detector provided at one end of the optical fiber is switched to the light source, and the other end is switched to the transmitted light measuring device corresponding to the light source that projects the other end, and the light transmission characteristic is changed. Is measured, the change in light loss of the system is identified, and the sensitivity is corrected from the data indicating the correlation between the light loss and the sensitivity, which is obtained in advance, so that the change with time in the sensitivity can be corrected.

An optical fiber radiation monitoring system according to a thirteenth aspect of the present invention includes a radiation sensor having a light entrance and exit through two or more optical fiber connectors, and an optical fiber is connected to the radiation sensor to receive radiation. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, the change of the transmission line, the sensor insertion loss or the connection loss by the backscattering light method is measured by using the system according to claim 6, and these light loss values and the counts of the individual radiation sensors determined in advance are measured. It is characterized in that the sensitivity of each radiation sensor is corrected based on the sensitivity correlation.

According to the present invention, during operation, the photodetector provided at one end of the optical fiber is switched to the optical fiber reflectometer of the Rayleigh scattering OTDR, and the reflection characteristic of the light is measured, whereby the transmission loss of the system is reduced. By identifying changes in optical loss such as connection loss, determining the soundness of the connection state of the system, and correcting the sensitivity based on data that shows the correlation between optical loss and sensitivity determined in advance, the sensitivity Can be corrected for the change with time.

An optical fiber radiation monitoring system according to a fourteenth aspect of the present invention is provided with a radiation sensor having a light entrance and exit through two or more optical fiber connectors. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, the temperature dependency of the half width of the peak corresponding to each radiation sensor in the arrival time difference distribution is calibrated and stored in advance, and the temperature of the sensor installation location is obtained based on the half width obtained at the time of measurement. It is assumed that.

According to the present invention, the distribution of arrival time differences from each radiation sensor during operation is measured by the multi-peak height analyzer, and the peak of each sensor on the distribution of arrival time changes depending on the ambient temperature where the radiation sensor is placed. The half-width can be measured, and it can be used for deriving the temperature by referring to the temperature and the calibration curve of the half-width determined in advance. In particular, since the radiation source is embedded in the sensor so that a constant light pulse is always transmitted from the radiation sensor, the radiation source is useful when radiation measurement is not the original purpose.

According to a fifteenth aspect of the present invention, there is provided an optical fiber radiation monitoring system including a radiation sensor having a light entrance and exit through two or more optical fiber connectors. Optical fiber radiation to obtain information on the position of the sensor and the intensity of the radiation by measuring the distribution of arrival time differences of the light pulses simultaneously sent out from the radiation sensor. In the monitor system, the characteristics of the count rate and dead time of the arrival time difference distribution measurement circuit system are stored in advance, and the dead time of the circuit system is calculated from the input count rate in the entire arrival time difference distribution obtained at the time of measurement using these. , And a correction coefficient associated with the radiation sensor. By equally applicable to the, it is characterized in that to obtain a true count rate.

According to the present invention, when the distribution of arrival time differences is measured by the multi-peak height analyzer, the relationship between the input count rate to the measurement circuit system including the time analysis system and the dead time is examined in advance, and the arrival time difference distribution is measured. By estimating the dead time of the measurement system based on the input count rate obtained from the total count of the above, and obtaining the true count rate corresponding to each radiation sensor, it becomes possible to correct the count rate measurement accuracy.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. The members common to the members described in the conventional example will be described using the same reference numerals as those in FIGS.

First Embodiment (FIGS. 1 to 3) FIG. 1 shows a system configuration of an optical fiber radiation monitoring system. This fiber optic radiation monitoring system
A radiation sensor having a light extraction port by two optical fiber connectors, for example, an optical waveguide type scintillator 7 is provided. The optical waveguide type scintillator 7 is connected in series to the data processing device 8 by the optical fiber 4.

FIG. 2 shows an optical fiber radiation monitoring system similar to that of FIG. 1. This system has a system in which an optical waveguide type scintillator 7 is connected to a data processing device 8 in parallel by an optical fiber 4. ing. The optical fibers 4 connected to both ends of each optical waveguide type scintillator 7
Are designed to be different if identification is required.

In the data processing device 8 of the optical fiber radiation monitoring system shown in FIGS. 1 and 2, a set of light pulses simultaneously sent from both ends of the optical waveguide type scintillator 7 are included in the data processing device 8. The time difference distribution until the light reaches the photodetector is measured.

FIG. 3 shows an embodiment according to the first aspect of the present invention, in which the arrival waveform of each optical pulse measured by the photodetector of the data processing device 8 is exemplified. That is, in FIG. 3, the vertical axis represents the count value of the light pulse with a peak, and the horizontal axis represents the time difference. Here, the effective sections of the peak are (a, b) and (c, d). Section (a,
The case of b) shows a case where the influence of the adjacent peak is not clearly affected. In this case, the area (count value) of the section (a, b) is obtained by simply integrating the count value to obtain the peak. (A net count value) can be obtained. On the other hand, the section (c, d) is clearly affected by adjacent peaks, and therefore, the area (count value) as shown by the cross-hatched lines in the figure in the region sandwiched by the sections (c, d). , The net count value of the peak (peak count value) can be obtained.

The radiation dose (rate) and the radioactivity concentration of the object to be measured are derived by performing arithmetic processing in consideration of these count values, conversion coefficients and equations (addition, subtraction, multiplication, and division) previously determined at the time of calibration, and measurement time. Is what you do.

The distribution data can be obtained by combining a histogram memory such as a multiplex analyzer capable of dividing and measuring all data sections into a finite number of sections, or a combination of a plurality of counting circuits having a wave height discrimination function. It can be performed by using a general measuring device.

Second Embodiment (FIG. 4) This embodiment corresponds to the second aspect of the present invention. In the same system as the system shown in FIG. 1 and FIG.
As shown in FIG. 4, this is a case where a plurality of time difference distributions of the data of the optical waveguide type scintillator 7 appear in the data processing device 8 in a superimposed manner.

That is, in the present embodiment, the distribution function indicating the entire data distribution of the plurality of optical waveguide scintillators 7 is

(Equation 1) It is assumed that

Here, fi (Δt) is a distribution function for each radiation sensor.
The entire distribution F (Δt) is expressed. A coefficient of each function is determined by performing a least squares regression calculation based on a function type assumed in advance, and a peak height or a peak net count (rate) value obtained from the function is calibrated in advance. By performing a calculation process in consideration of the conversion coefficient, formula, and measurement time obtained at the time, the radiation dose (rate) and the radioactivity concentration of the measurement target are derived. This distribution data can be obtained using the same measuring device as that described in the first embodiment.

Third Embodiment (FIG. 5) This embodiment corresponds to the third aspect of the present invention. As shown in FIG. 5, in this embodiment, the arrival time difference distribution of a plurality of optical waveguide scintillators 7 is different. The data is superimposed, and each data (count value) of the distribution is

(Equation 2) It is assumed that

Here, yi (Δt) is a known spectrum (rate) prepared in advance or a reference spectrum of each radiation sensor irradiated under a radioactivity concentration, and is reached by superimposing a coefficient times this spectrum. Time difference distribution Yi (Δt)
Is obtained by the least square regression calculation.

By performing the arithmetic processing in consideration of the coefficient value, the conversion coefficient, the expression, and the measurement time previously obtained at the time of calibration, the dose (rate) and the radioactivity concentration of the object to be measured can be derived.

For obtaining the distribution data, the same measuring device as described in the first embodiment can be used.

Fourth Embodiment (FIG. 6) This embodiment relates to the disclosure of the related art.
(A) is an optical waveguide type scintillator 7 as a radiation sensor.
FIG. 1B is a front view showing one configuration example, and FIG. 1B is a plan view thereof. FIG. 1C is a front view showing another configuration example, and FIG. 1D is a side view thereof. Each of these optical waveguide type scintillators 7 has a configuration in which a scintillator 10 is provided in a housing 9, and optical connectors (receptacles) 13 are attached to both ends of a wavelength shift fiber 12 in the housing 9. The optical connectors 13 attached to both ends of the wavelength shift fiber 12 are connected to transparent optical transmission optical fibers 4 respectively.

As shown in FIG. 6 (A), the optical waveguide type scintillator 10 of one configuration example includes a light guide 11, a pulse light source 14 for emitting pulsed light is mounted below the light guide 11, and a pulse guide. A shutter 15 is provided as a mechanism for turning on and off the irradiation of light from the light source 14 to the light guide 11. In another configuration example, FIG.
As shown in (C), the same pulse light source 14 and shutter 15 are provided at the lower part of the housing 9.

For example, in the case of the configuration shown in FIG. 6A, a shutter 15 is provided at the bottom of the light guide 11.
And the light source 14, the shutter 1 in the normal state
5 is closed to block external light, and shutter 1
When 5 is opened, the light pulse from the pulse light source 14 enters the light guide 11, is absorbed by the wavelength shift fiber 12, and the re-emitted fluorescent pulse is sent out to the optical fiber 4 connected to both ends. Has become. The mechanism for turning on / off the illumination of the pulse light is not limited to a light switch / breaker such as a shutter, but can be performed by attaching / detaching the light source itself.

As the pulse light source 14 used here,
It is necessary to match the absorption wavelength band of the wavelength shift fiber 12. For example, a material in which an α-ray source is brought into close contact with a scintillation substance of the same type as the scintillator 10 to be used is suitable.

According to the present embodiment, the optical operation of the system can be confirmed by detecting the light pulse from the pulse light source 14. That is, by using the shutter 15 and the pulse light source 14 attached to the optical waveguide type scintillator 7 and turning on the light irradiation at the time of system inspection, instead of irradiating the optical waveguide type scintillator 7 with radiation and causing the scintillator 10 to emit light. Then, an optical pulse having a known intensity and frequency is transmitted from the wavelength shift fiber 12, the optical pulse is detected, and if necessary, compared with the previous data, the optical waveguide type scintillator 7 and the optical transmission line are transmitted. Inspection and confirmation of the optical operation and soundness with the fiber 4 can be performed.

Fifth Embodiment (FIG. 7) This embodiment corresponds to the invention of claim 4. As shown in FIG. 7, an optical waveguide type scintillator 7 as a radiation sensor is connected in series with an optical fiber 4. In this case, a light source 16 is attached to one end 4a of the optical fiber 4, and light is supplied from the light source 16 to transmit the light through the system.

As the light source 16, any one of a monochromatic light source, a white light source and a light source of a specific wavelength band can be used. The lighting method is pulse light or continuous (CW).
Any of light can be used.

On the other hand, a transmission light measuring device 17 for measuring the power and spectrum of the transmitted light is mounted on the other end 4 b of the optical fiber 4. The connection status can be confirmed.

That is, in this embodiment, in order to check the operation of the optical wave type scintillator 7 as a radiation sensor, a light whose intensity or spectrum is known from one end 4a of the fiber 4 is connected to the sensor group with an optical fiber. Is transmitted, and the transmission intensity or spectrum thereof is measured at the other end 4b to obtain an optical loss value with respect to the transmitted light wavelength, and is compared with the previous measurement value.

In this way, it is possible to check and confirm the optical state or operation and soundness of the measurement system.

Sixth Embodiment (FIG. 8) This embodiment corresponds to the invention of claim 5, and as shown in FIG. 8, an optical waveguide type scintillator 7 as a radiation sensor is connected in series with an optical fiber 4. In this case, the one end 4a of the optical fiber 4 is provided with a Rayleigh scattering OTDR type (Optical Time Domain) for inspection.
n Reflectometer) is connected to the optical fiber reflectometer 18.

This optical fiber reflectometer 18
Based on the pulsed light incident from one end 4a of the optical fiber 4, the temporal change in the intensity of Rayleigh scattering and Fresnel reflected light is measured by a post-scattering light method, and the transmission loss value of the optical fiber 4 with respect to the incident light wavelength is measured. , For measuring the insertion loss or connection loss of the optical waveguide type scintillator 7. In this case, it is preferable that the light source be as close as possible to the fluorescence wavelength emitted from the optical waveguide type scintillator 7. Note that the other end 4b of the optical fiber 4 may be left open, and this embodiment has the configuration.

In this embodiment, in order to check the operation of the optical waveguide type scintillator 7, the optical waveguide type scintillator 7 group is connected with the optical fiber 4.
Pulsed light is incident from one end 4a of the optical fiber 4, and the temporal change in the intensity of the Rayleigh scattering and Fresnel reflected light at the same end is observed by the optical fiber reflectometer 18 by the post-scattering light method. By comparing the data with the previously measured data in accordance with the above, it is possible to check and confirm the optical state or the operation and soundness of the optical waveguide type scintillator 7 and the optical fiber 4.
That is, the optical state or operation of the system can be confirmed by checking the optical fiber 4 for breakage, bending, stress, abnormality of the sensor connector, and the like.

Seventh Embodiment (FIG. 9) This embodiment corresponds to the invention of claim 6, and a plurality of optical waveguide type scintillators 7 are connected in series by an optical fiber 4, as shown in FIG. In a system in which the data processing device 8 is connected to both ends of the optical fiber 4, calibration is performed by simultaneously irradiating radiation from a standard irradiation field or a calibration radiation source 6 having a known radioactivity concentration. Has become. The optical fiber 4 is wound by a mechanism or a jig (not shown) so as to have a diameter larger than the allowable bending radius.

According to such an optical fiber radiation monitoring system of the present embodiment, the whole system to which the optical waveguide type scintillator 7 is connected is used for the calibration for obtaining the radiation dose (rate) and the conversion coefficient or the expression to the radioactivity concentration. Is installed with respect to the calibration source 6, so that the entire optical fiber 4 and the optical waveguide type scintillator 7 are connected, and the entire optical system 4 is regarded as one measurement system. Since the radiation is simultaneously applied to the corrugated scintillator 7, it is particularly effective when the entire apparatus is a short, compact, small-scale temporary monitor or the like. Then, by performing irradiation calibration using a standard irradiation field or the like or a calibration radiation source 6 whose radioactivity concentration is known, calibration with light loss can be performed under the same conditions as actual operating conditions.

Eighth Embodiment (FIG. 10) This embodiment corresponds to the seventh aspect of the present invention.
Shows the system. In the optical fiber radiation monitoring system of the present embodiment, the optical waveguide type scintillator 7 to be inspected is connected to the test optical fiber 4 of the system including the variable optical attenuator 19 simulating the transmission loss value of light, The calibration is performed by irradiating the single wave scintillator 7 with radiation from the calibration source 6.

That is, one optical waveguide type scintillator 7
And the data processor 8 are connected by two optical fibers 4, and a variable optical attenuator 19 is interposed in each of the optical fibers 4. This variable optical attenuator 19
The transmission and connection loss due to the optical fiber 4 and other sensors interposed between the optical waveguide type scintillator 7 and the data processing device 8 can be simulated. The attenuation rate is adjusted to match the optical loss when connected to the system. When the photodetectors included in the data processing device 8 are separated, the separated photodetectors and the variable optical attenuator 19 are further connected by an optical fiber.

According to such a system of the present embodiment, with the individual optical waveguide scintillators 7 removed, the light interposed between the optical waveguide scintillator 7 and the data processing device 8 in the original measurement system. With a variable optical attenuator 19 capable of simulating the transmission and connection loss caused by the fiber 4 and other sensor groups interposed between the optical waveguide type scintillator 7 and the data processing device 8, a standard irradiation field, etc. By performing irradiation calibration using the calibration radiation source 6 whose radioactivity concentration is known, calibration can be performed under the same conditions as actual operating conditions. Therefore, in the calibration for obtaining the radiation dose (rate), the conversion coefficient and the expression to the radioactivity concentration, the optical waveguide type scintillator 7 is installed alone with respect to the calibration source 6,
Despite irradiation, calibration with light loss can be performed under the same conditions as actual use.

Ninth Embodiment The ninth embodiment corresponds to the eighth aspect of the present invention, and the individual optical waveguides described in the system shown in the seventh embodiment (FIG. 9) or the eighth embodiment (FIG. 10). With respect to the same data as shown in the first embodiment (FIG. 3) measured for calibration under the condition of a known radiation dose or radioactivity concentration, the peak corresponding to each optical waveguide type scintillator 7 was obtained. Is calculated directly by adding, subtracting, multiplying, and dividing the measured count value of the area containing, and taking into account the measurement time, deriving this value and a method of converting it to radiation dose or radioactivity concentration and storing it. .

That is, the effective sections of the peaks of the arrival time difference distribution as shown in FIG. 3 obtained at the time of calibration under the condition of the known radiation dose or radioactivity concentration by the calibration source 6 are (a, b), (c) , D). In the case of the section (a, b), the case where the influence of the adjacent peak is not clearly shown is shown. In this case, the area (count value) of the section (a, b) is obtained by simple integration of the count value. Can be used to determine the peak count value (net count value). On the other hand, the section (c, d) is clearly affected by adjacent peaks, and therefore, the area (count value) as shown by the cross-hatched lines in the figure in the region sandwiched by the sections (c, d). Is obtained to obtain the net count value of the peak (peak count value).

According to this embodiment, as a data processing unit for calibration, a peak effective section is set for each peak corresponding to each optical waveguide type scintillator 7 in the arrival time difference distribution, and the section of the section is set. The gross count, peak net time, or peak height is calculated by adding, subtracting, multiplying, or dividing the measured count value, using the measured time, the known radiation dose (rate) or radioactivity concentration, and the radiation dose (rate) or radioactivity concentration. By deriving and storing the conversion coefficient and expression to, quantitative measurement becomes possible.

Tenth Embodiment This embodiment corresponds to the ninth embodiment of the present invention, and each optical waveguide described in the system shown in the seventh embodiment (FIG. 9) or the eighth embodiment (FIG. 10). With respect to the same data as shown in the second embodiment (FIG. 4) measured for calibration under the condition of a known radiation dose or radioactivity concentration, the type of scintillator 7 corresponds to each optical waveguide type scintillator 7. The function of calculating the time difference distribution is calculated, taking into account the measurement time, and deriving and storing a conversion method to the radiation dose or the radioactivity concentration.

That is, the arrival time difference distribution obtained at the time of calibration as shown in FIG. 4 is obtained by superimposing data of a plurality of optical waveguide scintillators 7, and the distribution function showing the entire distribution is

(Equation 3) It is assumed that

Fi (.DELTA.t) is a distribution function for each optical waveguide type scintillator 7, and the overall distribution F (.DELTA.t) is expressed by superposition of the function type. The coefficient of the function is determined by performing least-squares regression based on the function type assumed in advance, and the peak height or peak net count (rate) value obtained from this function is compared with a known dose (rate) or By performing arithmetic processing using radioactivity concentration and measurement time,
It is possible to derive a conversion method such as a radiation dose (rate), a conversion coefficient or a formula for the radioactivity concentration.

According to the present embodiment, as the calibration data processing unit, a plurality of optical waveguide scintillators
Is obtained by regression calculation, and a coefficient type is determined by regression calculation, and each coefficient is determined. The information obtained from this function, the measurement time, and the By using the radiation dose or the radioactivity concentration to derive and store a conversion coefficient or formula for the radiation dose or the radioactivity concentration, quantitative measurement becomes possible.

Eleventh Embodiment The present embodiment corresponds to the tenth aspect of the present invention.
Second embodiment (FIG. 4) in which measurement was performed for each single optical waveguide type scintillator 7 described in the system shown in the embodiment (FIG. 10) for calibration under a condition of a known radiation dose or radioactivity concentration. With respect to the same data as shown in the above, the arrival time difference distribution corresponding to each optical waveguide type scintillator 7, the measurement time, and the radiation dose or radioactivity concentration corresponding to this distribution are stored.

That is, at the time of calibration, irradiation is performed for each optical waveguide type scintillator 7, and the radiation dose (rate) or the optical waveguide type scintillator 7 for a radiation source whose radioactivity concentration is known.
Measure the reference spectrum for each. At the time of measurement, as shown in FIG. 5, a distribution in which these data are superimposed is obtained, and each data (count value) of the distribution is

(Equation 4) It is assumed that

As a conversion method, calibration can be performed by recording the reference spectrum, the measurement time, the corresponding radiation dose (rate), or the radioactivity concentration.

According to the present embodiment, as the calibration data processing unit, a plurality of optical waveguide scintillators
Is measured as a superposition of the data of the optical waveguide type scintillator 7, and the individual arrival time difference distribution of the optical waveguide type scintillator 7 is measured, and the distribution and the measurement time are used to calculate the radiation dose or the radioactivity concentration. By deriving and storing coefficients and equations, quantitative measurements can be made.

Twelfth Embodiment This embodiment corresponds to the eleventh aspect of the present invention.
The optical change of each radiation sensor and optical fiber is identified from the change of the signal count value or the signal light intensity by the pulse light source 14 in the system shown in FIG. 6, and the light pulsar count value or light intensity and sensitivity determined in advance are determined. From the radiation based on the correlation with
Is used to correct the sensitivity.

That is, when the measurement is performed using the optical waveguide type scintillator 7 equipped with the pulse light source 14 shown in FIG. 6, not only the optical soundness check of the system described in the fourth embodiment but also the pulse With reference to the relational expression between the pulse intensity or the count value (rate) of the light source 14 and the previously obtained data of the pulse light source 14 and the sensitivity of the optical waveguide type scintillator 7, a calibration coefficient and a correction term of the expression are obtained. is there.

According to this embodiment, temporarily during operation,
By irradiating light from the pulse light source 14 mounted on the optical waveguide type scintillator 7 and comparing the count value, light intensity, and the like when the light detection unit detects the light with the previous measurement value, the light loss of the system is reduced. By identifying the change and correcting the sensitivity from the pulse light source data and the data indicating the correlation between the sensitivities obtained in advance, it is possible to correct the change with time of the sensitivity and improve the quantitative accuracy.

Thirteenth Embodiment This embodiment corresponds to the twelfth aspect of the present invention.
By measuring the change in light loss of the whole system in the system of FIG. 7,
On the basis of the correlation between the optical loss value of the entire system determined in advance and the counting sensitivity of each optical waveguide type scintillator 7,
The sensitivity of each optical waveguide type scintillator 7 is corrected.

That is, when the same measurement as in the system described in the fifth embodiment is performed using a system in which the light source 16 and the transmitted light detecting device 17 shown in FIG.
In addition to checking the optical soundness of the system, the transmitted light intensity or spectrum, the transmitted light data obtained in advance,
Referring to the relational expression with the sensitivity of the optical waveguide type scintillator 7,
This is for obtaining a correction coefficient or a correction term of an equation.

According to the present embodiment, the light detector provided at one end 4a of the optical fiber 4 is switched to the light source 16 during operation, and the transmitted light measuring device 17 corresponding to the light source that projects the other end 4b is used. By switching and measuring the light transmission characteristics,
By identifying the light loss change of the system and correcting the sensitivity from the data showing the correlation between the light loss and the sensitivity obtained in advance, it is possible to correct the change over time of the sensitivity and improve the quantitative accuracy. .

Fourteenth Embodiment This embodiment corresponds to the thirteenth aspect of the present invention.
A transmission path by the backscattered light method using the system shown in FIG. 8,
The change in the sensor insertion loss or the connection loss is measured, and based on the correlation between the optical loss value obtained in advance and the counting sensitivity of the optical waveguide scintillator 7 as an individual sensor, each of the optical waveguide type scintillators 7 is measured. This is for correcting the sensitivity of the scintillator 7.

That is, the optical fiber OTD shown in FIG.
When performing the same measurement as described in the sixth embodiment using a system in which the R-type reflectometer 18 is attached to one end of the optical fiber 4, not only the optical soundness of the system but also the transmission loss and connection The calibration coefficient and the correction term of the equation are obtained by referring to the data such as the loss and the relational expression between the previously obtained light loss data and the sensitivity of the optical waveguide type scintillator 7.

According to the present invention, during operation, the photodetector provided at one end 4a of the optical fiber 4 is provided with the Rayleigh scattering OTDR.
By switching to the reflectometer 18 and measuring the reflection characteristics of light, changes in optical loss such as transmission loss and connection loss of the system are identified, and a function to determine the soundness of the connection state of the system and a function previously determined. The sensitivity can be corrected based on data representing the correlation between the light loss and the sensitivity. Therefore, it is possible to correct a change in sensitivity over time, thereby improving the quantification accuracy.

Fifteenth Embodiment (FIG. 11) This embodiment corresponds to the fourteenth aspect of the present invention .
This will be described with reference to FIG.

The optical fiber radiation monitor system of this embodiment calibrates and stores in advance the temperature dependence of the half value width of the peak corresponding to each optical waveguide type scintillator 7 in the distribution of arrival time differences, and obtains the half value width obtained at the time of measurement. Is used to determine the temperature of the scintillator installation location.

That is, the peak half width of the arrival time difference distribution changes with the temperature change of the light emission decay time of the scintillator. By utilizing this characteristic, the function of deriving the ambient temperature from the half width is realized. Can be. In this case, when there is no radiation source above the natural radiation level in the surroundings and the count rate for temperature measurement is insufficient, a method such as placing a γ or β ray source directly or near the optical waveguide type scintillator 7 is used. Can respond.

According to the present embodiment, the distribution of arrival time differences from each optical waveguide type scintillator 7 during operation is measured by the multi-wave height analyzer, and the arrival time difference distribution which varies depending on the ambient temperature where the optical waveguide type scintillator 7 is placed. The half width of the peak of each optical waveguide type scintillator 7 is measured, and the temperature and the calibration curve of the half width are obtained in advance, and the temperature can be derived. In particular, if the radiation source is integrally mounted by being embedded in the sensor or the like, a function of constantly sending a constant light pulse from the optical waveguide type scintillator 7 is provided. Useful for

Sixteenth Embodiment (FIGS. 12 and 13) This embodiment corresponds to the invention of claim 15.
This will be described with reference to FIGS.

The optical fiber radiation monitoring system according to the present embodiment stores in advance the characteristics of the counting rate and dead time of the arrival time difference distribution measuring circuit system, and utilizes these in the entire area of the arrival time difference distribution obtained during measurement. Deriving the dead time of the circuit system and the correction coefficient related thereto from the input count rate,
By applying this correction coefficient equally to the count rate obtained for each optical waveguide type scintillator 7, a true count rate is obtained.

That is, the arrival time difference distribution is one TDC
(Time-Digital Converter),
Alternatively, one TAC (Time-to-Amplit)
ude Converter) is used as a first stage processing circuit to analyze the time difference and record it with a general measurement circuit system, such as recording with a histogram memory of a multiplex wave height analyzer or a device combining a plurality of counting circuits. . In any case, there is a dead time of the measurement circuit system.

Therefore, it is necessary to calibrate the relationship between the count rate input to this measuring circuit system and the dead time in advance as shown in FIG. At the time of the measurement, as shown in FIG. 18, the input count rate to the circuit system is calculated from the entire area of the arrival time difference distribution, the dead time obtained from this count rate is obtained from the calibration information, and each optical waveguide type scintillator 7 is By correcting all the measurement count rates obtained in this way and obtaining the true count rate corrected for the dead time, the quantitative accuracy can be maintained irrespective of the input count rate.

According to the present invention, when the distribution of arrival time differences is measured by a multi-peak height analyzer, the relationship between the input count rate to the measurement circuit system including the time analysis system and the dead time is examined in advance, and the distribution of arrival time differences is determined. By estimating the dead time of the measurement system based on the input count rate obtained from the total count of the above, and obtaining the true count rate corresponding to each optical waveguide type scintillator 7, it is possible to correct the count rate measurement accuracy.

[0099]

As described in detail above, according to the optical fiber radiation monitoring system of the present invention, not only the relative measurement of the radiation level but also the calibration as a system for deriving the dose (rate) and the radioactivity concentration. , Inspection and correction, and furthermore, excellent effects such as securing stability against temperature change, deriving the ambient temperature, and realizing use in a high temperature environment can be achieved.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention and is a system diagram of an optical fiber radiation monitor in which optical waveguide scintillators are connected in series.

FIG. 2 shows the first embodiment of the present invention and is a system diagram of an optical fiber radiation monitor in which optical waveguide scintillators are connected in parallel.

FIG. 3 shows the first embodiment of the present invention, and is an explanatory diagram of a calculation method by counting and integrating from the arrival time difference distribution.

FIG. 4 is a view showing a second embodiment of the present invention, and is an explanatory diagram of a calculation method by function fitting from a distribution of arrival time differences.

FIG. 5 is a view illustrating a third embodiment of the present invention, and is a diagram illustrating a calculation method based on distribution superposition regression from an arrival time difference distribution.

FIG. 6 discloses a related art of the present invention as a fourth embodiment, showing a structure of an optical waveguide type scintillator and a mounting example of a pulse light source, wherein (A) is a front view showing one configuration example, and (B).
Is a plan view, (C) is a front view showing another configuration example, and (D) is a front view.
Is its side view.

FIG. 7 shows a fifth embodiment of the present invention, and is an explanatory diagram of a system for inspection and correction of calibration information using transmitted light.

FIG. 8 shows a sixth embodiment of the present invention, and is an explanatory diagram of a system for inspection and correction of calibration information by an optical fiber OTDR reflectometer.

FIG. 9 shows the seventh embodiment of the present invention, and is an explanatory diagram of a calibration system in a multipoint connection state.

FIG. 10 shows an eighth embodiment of the present invention, and is an explanatory diagram of a calibration system using a single sensor and a variable optical attenuator.

FIG. 11 shows the fifteenth embodiment of the present invention, and is an explanatory diagram of temperature measurement based on the half value width of distribution of arrival time difference.

FIG. 12 shows the sixteenth embodiment of the present invention, and is an explanatory diagram of an increase characteristic of a dead time with respect to an input count rate.

FIG. 13 is a view showing a seventeenth embodiment of the present invention, and is an explanatory diagram of correction of a count rate by an arrival time difference distribution total count rate.

FIG. 14 shows a conventional example and is an explanatory view of a radiation monitoring apparatus.

FIG. 15 shows a conventional example, and is an explanatory view of a calibration system of a sensor for a radiation monitoring apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection part 2 Metal cable 3 Multiplexer 4 Optical fiber 4a One end of optical fiber 4b The other end of optical fiber 5 Data processing device 6 Calibration radiation source 7 Optical waveguide type scintillator 8 Data processing device 9 Housing 10 Scintillator 11 Light guide 12 Wavelength shift fiber 13 Optical connector (receptacle) 14 Light source 15 Shutter 16 Light source 17 Transmitted light measuring device 18 Optical fiber OTDR reflectometer 19 Variable optical attenuator 20 Wavelength shift fiber

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Yoda 1 Kosaka Toshiba-cho, Koyuki-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center (56) References JP-A-6-258446 (JP, A) JP-A-56-100379 (JP, A) JP-A-7-311269 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01T 1/00-7/12 G21C 17/00

Claims (15)

(57) [Claims] 1. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of the radiation by measuring the arrival time difference distribution of the light pulses simultaneously sent from the radiation sensor, the measurement data is a plurality of radiation sensors When observed as a superposition of the data, the net count value or the peak count value of the region including the peak corresponding to each radiation sensor, the waveform value at the start point and end point of the effective section of the peak of the measurement target waveform The large waveform value is subtracted from the waveform in the effective section of the peak and integrated, and the radiation dose or Is an optical fiber radiation monitor system for deriving a radioactivity concentration. 2. A radiation sensor having a light entrance / exit by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of the radiation by measuring the arrival time difference distribution of the light pulses simultaneously sent from the radiation sensor, the measurement data is a plurality of radiation sensors When observed as a superposition of the data of each of the radiation sensors, the coefficient of each function is determined by regression calculation as a function type superposition adapted to the arrival time difference distribution of each radiation sensor. In addition to the above, the engineering unit conversion is further performed to derive the radiation dose or radioactivity concentration. Fiber optic radiation monitoring system. 3. A radiation sensor having a light entrance / exit by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In a fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of the radiation by measuring the arrival time difference distribution of the light pulses simultaneously sent from the radiation sensor, the measurement data is obtained from a plurality of sensors. When observed as superimposition of data, the individual arrival time difference distributions of the respective radiation sensors acquired under constant irradiation conditions are prepared in advance, and these distributions are regression-calculated assuming that these are multiplied by the respective coefficients and superimposed. Is determined, taking into account the measurement time, this coefficient and the radiation or radioactivity at the time of irradiation. An optical fiber radiation monitoring system, which derives a final radiation dose or radioactivity concentration based on information. 4. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In a fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the operation of the radiation sensor is checked. In a state where the radiation sensor group is connected by an optical fiber, light having a known intensity or spectrum is transmitted from one end of the optical fiber, and the transmitted intensity or spectrum is measured at the other end, and the light corresponding to the transmitted light wavelength is measured. By determining the loss value and comparing it with the previous measurement, the optical state of the measurement system Or an optical fiber radiation monitor system for confirming operation. 5. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In a fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the operation of the radiation sensor is checked. In a state where the radiation sensors are connected by an optical fiber, pulsed light is incident from one end of the optical fiber, and the temporal change in the intensity of the Rayleigh scattering and Fresnel reflected light at the same end is detected by post-scattered light. Transmission loss value of the optical fiber with respect to the wavelength of the incident light, insertion loss of the optical sensor An optical fiber radiation monitor system for measuring the loss or connection loss, and checking the optical state or operation of the system by checking the fiber for cuts, bends, stresses, abnormalities in sensor connectors, and the like. 6. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the optical fiber and radiation actually used After considering the whole system as one measurement system with the sensor connected, perform calibration by irradiating radiation to individual radiation sensors individually or simultaneously from a radiation source for calibration to multiple radiation sensors. A fiber optic radiation monitoring system characterized by performing: 7. A radiation sensor having a light entrance / exit by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the transmission loss value of light is simulated. An optical fiber characterized by connecting a radiation sensor to be tested to a test optical fiber of a system including a variable optical attenuator, and irradiating a single radiation sensor with radiation from a calibration source to perform calibration. Radiation monitoring system. 8. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is extracted and transmitted to a data processing device. 9. The optical fiber radiation monitoring system according to claim 7, wherein information on the position of the sensor and the intensity of the radiation is obtained by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor. For each radiation sensor in the system, the net count value or peak count value of the area containing the peak corresponding to each radiation sensor is calculated for the data measured for calibration under the condition of the known radiation dose or radioactivity concentration. It is directly obtained by addition, subtraction, multiplication and division of the measurement count value, taking into account the measurement time,
An optical fiber radiation monitor system, which derives and stores this value and a method of converting it into a radiation dose or a radioactivity concentration. 9. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. 9. The optical fiber radiation monitoring system according to claim 7, wherein information on the position of the sensor and the intensity of the radiation is obtained by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor. To the data measured for calibration under the condition of the known radiation dose or radioactivity concentration for each radiation sensor in the system, find the fitting function of the arrival time difference distribution corresponding to each radiation sensor, taking into account the measurement time It is important to derive and store this and the method of conversion to radiation dose or radioactivity concentration. Fiber optic radiation monitoring system. 10. A radiation sensor having a light entrance / exit by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. 9. An optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses transmitted simultaneously from the radiation sensor. With one radiation sensor connected, the known radiation dose of each radiation sensor, or the arrival time difference distribution measured for calibration under the condition of radioactivity concentration, measurement time, radiation dose or radiation corresponding to this distribution An optical fiber radiation monitoring system characterized by storing active density. 11. A radiation sensor having a light entrance / exit by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In a fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the pulse light source according to claim 4 is used. From changes in signal counts or signal light intensity, optical changes in individual radiation sensors and optical fibers are identified,
An optical fiber radiation monitor system, wherein the sensitivity of a radiation sensor is corrected based on a correlation between a light pulsar count value or light intensity and sensitivity obtained in advance. 12. A radiation sensor having a light entrance and exit through two or more optical fiber connectors. An optical fiber is connected to the radiation sensor to take out light generated by the incidence of radiation and to transmit the light to a data processing device. A fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor. It is characterized by measuring the change in light loss of the whole system, and correcting the sensitivity of each radiation sensor based on the correlation between the light loss value of the whole system and the counting sensitivity of each radiation sensor that was obtained in advance. Fiber optic radiation monitoring system. 13. A radiation sensor having an entrance and exit of light by two or more optical fiber connectors. An optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In a fiber optic radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, the system according to claim 6 is used. The change in the transmission path, sensor insertion loss or connection loss by the backscattered light method is measured, and based on the correlation between these light loss values and the counting sensitivity of each radiation sensor determined in advance, the radiation sensitivity of each radiation sensor is measured. An optical fiber radiation monitor system, wherein the sensitivity is corrected. 14. A radiation sensor having a light entrance and exit through two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system for obtaining information on the position of the sensor and the intensity of the radiation by measuring the distribution of the arrival times of the light pulses simultaneously sent from the radiation sensor, An optical fiber radiation monitor system comprising: calibrating and storing the temperature dependency of the half width of a peak corresponding to the above, and obtaining the temperature of the sensor installation location based on the half width obtained at the time of measurement. 15. A radiation sensor having a light entrance and exit through two or more optical fiber connectors, an optical fiber is connected to the radiation sensor, and light generated by the incidence of radiation is taken out and transmitted to a data processing device. In the optical fiber radiation monitoring system that obtains information on the position of the sensor and the intensity of radiation by measuring the arrival time difference distribution of light pulses simultaneously sent from the radiation sensor, The characteristics of the count rate and the dead time are stored, and the dead time of the circuit system and the correction coefficient relating to the dead time are derived from the input count rate in the entire arrival time difference distribution obtained at the time of measurement by using them. A true counting rate is obtained by applying the correction coefficient equally to the counting rate obtained for each radiation sensor. Fiber optic radiation monitoring system.