JPH09218270A - Neutron measurement system and radiation measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accommodate demand for an increase in size and resistance against radioactive rays with a simple structure by providing a wire applied with a nuclear transformation substance in a container with gas which emits light under existence of charged particles sealed and transmitting an optic signal generated by the gas via an optic fiber. SOLUTION: When neutrons (n) from a neutron generation source are received by a sensor 1 and absorbed at an arbitrary position of a wire 4 in a container 3, charged particles (e) are emitted from a neutron absorbed position P to be measured, and gas 6 issues an optic signal OS along an orbit of the charged particles (e). The optic signal OS is received by an optic fiber 5 in the vicinity of the neutron absorbed position P as an expected quantity of light and transmitted to two photoelectric converters 8 from a light introduced position via the optic fiber 5. Detection signals S1, S2 of the photoelectric converters 8 are output to a signal processor 9, difference in quantities of light across the optic fiber 5 is calculated, the light introduced position of the optic fiber 5 is specified from the difference, the neutron absorbed position P of the wire 4 is estimated, and the estimated results are monitored as data regarding an spatial output distribution of neutrons.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a neutron measuring system and a radiation measuring system such as a neutron spatial power distribution monitor and a medical positron CT apparatus mounted around a nuclear reactor, and more particularly to a sensor using an optical cable and its sensor. Signal processing system.

[0002]

2. Description of the Related Art Conventionally, a neutron measuring system for measuring neutrons and a radiation measuring system for measuring ionizing radiation are
As described below, various sensors are used according to the application, measurement target, measurement method, and the like.

(1): A fission chamber is used in a neutron measurement system for measuring neutrons in a nuclear reactor core because radiation resistance is required.

(2): As a neutron measuring system for two-dimensionally measuring neutrons, a system utilizing a multi-wire chamber, a semiconductor detector, etc. is known. Also known is a light emitting sensor using a wire for applying a high voltage as a proportional scintillation counter.

(3): In a radiation measuring system for measuring a three-dimensional distribution of ionizing radiation, not limited to neutrons, a scintillator made of plastic or inorganic crystal is used for carrying out a CT method typified by, for example, a medical CT apparatus. A solid-state radiation detector such as a semiconductor detector or a semiconductor detector is often used.

On the other hand, in recent years, in operation of radiation control and the like, a measuring device (neutron spatial output distribution monitoring device) for monitoring the spatial output distribution of neutrons emitted from the reactor to the outside has been installed around the reactor. Is required, and application of the above-described measuring system to this measuring device is under study.

[0007]

However, when the conventional measuring system of the above (1) to (3) is applied to the above measuring apparatus, there are the following problems.

First, as a neutron measurement system to be installed around the reactor, A): the radiation resistance of the sensor which can be used even if the neutron measurement system is arranged in a place near the reactor where the radiation level is relatively high, B): It is necessary to simultaneously satisfy the structural constraints for constructing a sensor suitable for upsizing that can cover the circumference of the reactor as a measurement range.

In order to satisfy the above restrictions A) and B) at the same time, existing inorganic or organic scintillators having a problem of radiation resistance cannot be used, and for example, an existing ionization chamber or the like is combined to increase the size. However, in this case, not only the number of detectors simply increases, but also the signal processing system such as the measurement circuit becomes enormous, the signal processing amount also increases, and the entire apparatus is complicated and expensive. It becomes something like. This tendency becomes remarkable, including the problem of radiation resistance, when the existing sensor used for the two-dimensional neutron measurement system is applied.

Therefore, in spite of the above-mentioned demand for a larger size, the existing sensor used in the conventional neutron measurement system is suitable for a larger size including the problems of radiation resistance and cost. However, it was difficult to actually install it around the reactor as a measuring device.

On the other hand, considering that the existing sensor used in the radiation measuring system of (3) is applied to the measuring device, not only the radiation resistance of the detector remains unsolved, but also Since it is necessary to install detectors at each measurement position, the number of detectors, measurement circuits, signal processing amount, etc. will be large in order to increase the size, and the entire device will be complicated and expensive as above. I will end up.

With respect to this radiation measuring system, in addition to the above-mentioned request for a larger size, the apparatus configuration including the sensor and its signal processing system is simple and inexpensive, while making maximum use of the advantages of the CT method. Therefore, it is desired to be widely used in, for example, a medical CT device which is not limited to a nuclear reactor and is not limited to a specific field.

The present invention has been made in consideration of the above-mentioned problems of the prior art, and it is possible to construct a sensor and a signal processing system simply and relatively inexpensively. A first object is to provide a neutron measurement system and a radiation measurement system that can be applied to a spatial output distribution monitoring device and the like.

A second object is to provide a neutron measuring system and a radiation measuring system, which are suitable for a measuring device having enhanced versatility, while making use of the advantages of the CT method, at a relatively low cost.

[0015]

In order to achieve the above first and second objects, the present inventor has combined an optical fiber excellent in radiation resistance and an inert gas excellent in radiation resistance, Focusing on the idea of using a sensor that optically transmits the emission of gas through an optical fiber for neutron measurement, develop that idea to the range that also covers two-dimensional neutron measurement and three-dimensional radiation measurement based on CT method, result,
The following inventions have been completed.

That is, the neutron measurement system according to the first aspect of the present invention comprises a sensor for detecting neutrons from a neutron source, and a signal processing system for acquiring information on the neutrons from a detection signal of the sensor. It is configured.

Here, the sensor is a container in which a gas that emits light in the presence of charged particles is enclosed, and the sensor is arranged in the container and absorbs the neutron when the neutron is received in the container. A wire coated with a transmutation substance that emits charged particles on the surface, and in the presence of the charged particles emitted from the transmutation substance when the neutron is absorbed by the wire and is arranged in the vicinity of the wire. An optical cable that receives an optical signal emitted by the gas at a position near the wire and optically transmits the optical signal.

Further, the signal processing system includes a data acquisition means for acquiring at least data regarding the neutron absorption position of the wire based on the optical signal optically transmitted by the optical cable.

According to a second aspect of the present invention, in the neutron measurement system according to the first aspect, the data acquisition means is
A photoelectric conversion unit that individually converts each optical signal of both ends of the optical cable into an electric signal and detects the electric signal, and a position for measuring data regarding a neutron absorption position of the wire based on the electric signal detected by the photoelectric conversion unit. And measuring means.

According to a third aspect of the present invention, in the neutron measurement system according to the second aspect, the position measuring means detects the optical signals of both ends of the optical cable based on the electric signal detected by the photoelectric conversion means. It is a means for obtaining data regarding the difference in the amount of light from each other and measuring the data regarding the neutron absorption position of the wire from the data.

According to a fourth aspect of the present invention, in the neutron measurement system according to the second aspect, the position measuring means detects the optical signal of each end of the optical cable based on the electric signal detected by the photoelectric conversion means. It is a means for obtaining data regarding the light transmission time difference and measuring data regarding the neutron absorption position of the wire based on the data.

According to the invention of claim 5, claims 1 to 4
In the neutron measurement system according to any one of 1 to 3, further comprising a high-voltage power supply that generates a high voltage that induces proportional fluorescence due to self-propagation with respect to the optical signal emitted by the gas,
The high voltage power supply is connected to the wire.

According to the invention of claim 6, claims 1 to 5 are provided.
In the neutron measurement system according to any one of 1 above, the wires are a plurality of wires, the plurality of wires are arranged in the container, and the optical cable is a single optical cable. An optical cable is arranged in a stretched manner inside the container so as to pass near the respective wires.

According to a seventh aspect of the invention, in the neutron measurement system according to the sixth aspect, the position measuring means is based on an electric signal detected by the photoelectric conversion means, and is a data regarding a two-dimensional neutron absorption position in the container. Is a means for measuring.

According to the invention described in claim 8, claims 1 to 5 are provided.
In the neutron measurement system according to any one of 1, the neutron source is a cylindrical reactor, and the container is a cylindrical container having an inner diameter larger than the outer diameter of the reactor. It is arranged at a position that covers the periphery of the reactor and receives neutrons emitted from the reactor to the outside.

According to a ninth aspect of the present invention, in the neutron measurement system according to the eighth aspect, the position measuring means obtains data on the neutron flux space distribution of the nuclear reactor based on the electric signal detected by the photoelectric conversion means. It is a means of measuring.

According to a tenth aspect of the present invention, in the neutron measurement system according to any one of the second to ninth aspects,
The data acquisition means counts the number of pulses of the optical signal for each neutron absorption event of the wire based on the electrical signal detected by the photoelectric conversion means, and based on the counting rate of the unit time of the number of pulses. It is equipped with a means for measuring data on the neutron flux absorbed by the wire.

According to an eleventh aspect of the present invention, in the neutron measurement system according to any one of the fifth to ninth aspects,
The data acquisition unit detects an electric signal induced in each of the plurality of wires when a charged particle is emitted from the transmutation substance, and selects the plurality of wires based on each electric signal. It is equipped with a means to do.

According to a twelfth aspect of the invention, in the neutron measurement system according to any one of the fifth to ninth aspects,
The data acquisition means detects an electric signal induced in each of the plurality of wires when the transmutation substance emits a charged particle, and integrates the respective electric signals to each of the plurality of wires. It is equipped with a means for measuring the data on the amount of neutrons absorbed in.

According to a thirteenth aspect of the invention, in the neutron measurement system according to any one of the first to twelfth aspects, the optical cable is arranged in the container in a state orthogonal to the axial direction of the wire.

According to a fourteenth aspect of the present invention, in the neutron measurement system according to any one of the fifth to twelfth aspects, the plurality of wires are arranged in a mesh in the container.

According to a fifteenth aspect of the invention, in the neutron measurement system according to any one of the first to fourteenth aspects, a separate optical cable passing through a position separated from the vicinity of the wire is arranged in the container. .

A radiation measuring system according to a sixteenth aspect of the present invention comprises a sensor for detecting ionizing radiation from a radiation source and a signal processing system for obtaining information on the ionizing radiation from a detection signal of the sensor. With the configuration, the sensor has a wire and a container enclosing a gas that emits light when the ionizing radiation passes, and an optical signal emitted by the gas that is arranged in the vicinity of the wire An optical cable for receiving and optically transmitting at a near position, and the signal processing system includes a data acquiring unit for acquiring at least data regarding a passing position of the ionizing radiation based on the optical signal optically transmitted by the optical cable. ing.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIG.
It will be described based on. The first embodiment is implemented by applying the neutron measurement system according to the present invention to a neutron spatial output distribution monitoring device (hereinafter, simply “monitoring device”) such as a nuclear reactor.

The monitoring device shown in FIG. 1 monitors neutrons n from a neutron source such as a nuclear reactor (not shown), and a sensor 1 for detecting the neutrons n, and neutron data from the detection signal of the sensor 1. And a signal processing system 2 equipped with the data acquisition means of the present invention.

The sensor 1 uses neutrons n from a neutron source.
A rectangular parallelepiped measurement container 3 arranged at a position for receiving (for example, the periphery of the reactor when the neutron source is a reactor), and an arbitrarily determined measurement direction in the container 3,
For example, a wire 4 loaded along the vertical direction (see FIG. 1) in the container and an optical fiber (optical cable) 5 arranged in the vicinity of the wire 4 and having excellent radiation resistance are provided.

The container 3 is mainly composed of an inert gas such as argon or xenon which emits light upon receiving ionizing radiation (charged particle beam) or a mixed gas composed of two or more kinds of inert gas, and has excellent radiation resistance. The measuring gas 6 is enclosed.

The wire 4 absorbs neutrons such as ²³⁵ U and ¹⁰ B coming from a neutron source outside the container 3 and absorbs neutrons such as fission fragments (“FF”) or charged particle beams e such as α rays. The surface is coated with a nuclear transmutation substance 7 that emits. Therefore, the charged particle beam e emitted by the neutron absorption by the transmutation substance 7 of the wire 4 loses energy at a range (distance) of several mm to several cm and stops. At the position in the container 3 along the track of the charged particle beam e, N pieces (Ν =) determined by the quantity W _ph peculiar to the gas state such as the gas 6 and the pressure and the energy E in the initial state of the charged particle beam e. E / W _ph ) is generated.

The optical fiber 5 is made of gas 1 with respect to its material, shape, and geometrical arrangement conditions with respect to the wire 4.
It is set so as to have sufficient sensitivity to light in the emission wavelength region and to sufficiently guide the optical signal OS in the wavelength region. That is, the optical fiber 5 has an emission wavelength of the gas 6,
That is, the wire 4 is mainly composed of a scintillation fiber that absorbs an optical signal OS having a wavelength in the vacuum ultraviolet region and re-emits light, an optical fiber mixed with or coated with a wavelength conversion material, and the like.
Is arranged along the wire 4 within the range of the charged particle beam e from the above, for example, within the vicinity of several mm.

Therefore, the optical fiber 5 receives the optical signal OS emitted by the gas 6 at its light emitting position, that is, at a position near the neutron absorbing position P of the wire 4, which is considered to be almost the same, and at the same time receives the optical signal. The OS is optically transmitted to the signal processing system 2.

The signal processing system 2 is connected to both ends of the optical fiber 5 outside the container 3, and is connected to the photoelectric conversion devices (optical sensors) 8 forming the photoelectric conversion means of the present invention and its output side. Signal processing device 9 equipped with the position measuring means of the present invention.

The photoelectric conversion devices 8 and 8 are those to which a photomultiplier tube (“PMΤ”: Photomultiplier) or a photodiode (PD) is applied, and an optical signal OS from the optical fiber 5 is converted into an electrical signal corresponding to the light amount. The signal is converted into a signal, detected, subjected to processing such as amplification, and output to the signal processing device 9.

The signal processing device 9 is equipped with, for example, a microcomputer having a CPU as a main part, and executes a preset light quantity measurement algorithm or the like to output signals from the photoelectric conversion devices 8 and 8. S1, S2
Based on the above, the light amounts of the optical signals OS optically transmitted to the both ends of the optical fiber 5 are compared, and the optical transmission distance, that is, the optical fiber, is determined from the light amount comparison result and the preset light attenuation characteristic of the optical fiber 5. The light guide position of 5 is specified, and the neutron absorption position P of the wire 4 corresponding to the light guide position is estimated. The estimated neutron absorption position P can be constantly monitored by the operator via an output device such as a monitor (not shown).

Here, the measurement principle of the signal processing device 9 will be described.

First, as an initial condition to be set in advance, position data relating to the geometrical relationship between the optical fiber 5 and the wire 4 is set in advance, and the amount of light emitted from the wire 4 is set to be constant for each neutron absorption event. Then, the amount of light received by the optical fiber 5 can be predicted in advance using the position data and the amount of light emission as initial values. Actually, the amount of the charged particles e generated from the nuclear transmutation material 7 has a certain distribution in the case of fast neutrons, but can be regarded as practically almost constant, and almost constant in the case of thermal neutrons. Can be considered. Therefore, if the positional relationship between the wire 4 and the optical fiber 5 is preset as described above, the amount of light received by the optical fiber 5 guided from the neutron absorption position P of the wire 4 can be predicted.

Since the amount of light received by the optical fiber 5 can be predicted in this way, if the attenuation ratio in optical transmission, that is, the attenuation characteristic with respect to the distance of the optical fiber 5, is known, the optical fibers detected by the photoelectric conversion devices 8 and 8 are detected. The difference between the light amounts (light collection amounts) of the optical signals OS at both ends of the optical fiber 5 depends only on the attenuation characteristics of the optical signal, and two output signals S at both ends of the optical fiber 5 are provided.
The light transmission distance, that is, the light guide position can be specified from 1 and S2, and the neutron absorption position P of the wire 4 can be estimated from the light guide position.

Next, the overall operation of this embodiment will be described.

First, the monitoring device is activated, the neutron n from the neutron source (not shown) is received by the sensor 1, and the container 3
It is assumed that the wire 4 has been absorbed at an arbitrary position. Then, the charged particle e is emitted from this arbitrary position, that is, the neutron absorption position P to be measured, and the gas 6 emits the optical signal OS along the track. The optical signal OS is received by the optical fiber 5 near the neutron absorption position P as a light amount predicted in advance, and is optically transmitted from the light guide position to the photoelectric conversion devices 8 and 8 via the optical fiber 5. It

Next, the optical signal OS optically transmitted in this way
Are individually converted into electric signals by the photoelectric conversion devices 8 and 8 and detected, and both detection signals S1 and S2 are detected by the signal processing device 9.
Is output to Therefore, the light amount difference between both ends of the optical fiber 5 is calculated, the light guide position of the optical fiber 5 is specified from the light amount difference, and the neutron absorption position P of the wire 4 is estimated. This estimation result is monitored in real time as data on the spatial output distribution of neutrons, and is displayed on a monitor or the like so that the operator can constantly monitor it, for example.

Therefore, according to this embodiment, the neutron data is measured by the sensor that optically transmits the light emitted from the gas having excellent radiation resistance through the optical fiber having excellent radiation resistance. It is possible to construct a simple sensor structure having a wide range of application for various applications using a container filled with the and the optical fiber at a relatively low cost. This effect is maximized when it is applied to, for example, a measuring device around a nuclear reactor, which requires radiation resistance and size increase.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In the first embodiment, the light quantity measurement is used to identify the light guide position, but in this embodiment, the time difference measurement focusing on the light transmission time in the optical fiber is applied. Here, the description of the components substantially equivalent to those of the first embodiment will be simplified or omitted.

The monitoring device shown in FIG. 2 is obtained by partially modifying the signal processing system 2, and the signal processing system 2 has a predetermined time difference analyzer (“ΤDC”: Time-to-Digital Converter) 1.
0 is added, and this DC 10 is inserted between the photoelectric conversion devices 8 and 8 and the signal processing device 9. Other configurations are substantially the same as those in the first embodiment.

The TDC 11 receives the detection signals S1 and S2 of the photoelectric conversion devices 8 and 8 and analyzes the time difference of the optical transmission to the both ends of the optical fiber 5 with a predetermined accuracy, and signals the analyzed time difference data. It is supplied to the processing device 9.

The signal processing device 9 executes the preset algorithm for measuring the time difference to obtain T
The optical transmission distance in the optical fiber 5 is obtained based on the data regarding the time difference from the DC 11, and the neutron absorption position P of the wire 4 is estimated.

Here, the light is about 3 × 10 ⁸ m in vacuum.
/ Sec and propagates in the medium at a velocity slower than the vacuum velocity, so TDC 10 lnsec
If the time analysis is performed with a degree of accuracy (accuracy that can be sufficiently achieved by the processing capacity of ordinary TDC), the light guide position to be measured is 30
It can be estimated with a resolution of about cm or less.

Therefore, according to this embodiment, the first
In addition to the same effect as the embodiment, there is an advantage that the measurement accuracy is further enhanced.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. This embodiment focuses on the proportional fluorescence (proportional scintillation) phenomenon to improve the light receiving efficiency. Here, the description of the components substantially equivalent to those of the second embodiment will be simplified or omitted.

The monitoring device shown in FIG. 3 further comprises a high voltage power source (“HV”) 11 in addition to the configuration of the sensor 1 and the signal processing system 2, and this HV 11 is connected to the wire 4 coated with the transmutation substance 7. It was done. Other configurations are substantially the same as those of the second embodiment.

This monitoring device applies a high voltage generated by the HV 11 to the wire 4, and at a position within the container 3 along a track of the charged particle beam e emitted by the neutron absorption of the wire 4 above a predetermined value. By applying a high electric field, the proportional fluorescence phenomenon of light is promoted, the light emission of the gas 6 is self-propagated, and the light amount of the optical signal OS is increased.

Therefore, according to this embodiment, since the high voltage for inducing the proportional fluorescence phenomenon is applied to the wire 3, the light receiving efficiency of the optical fiber 5 is further improved in addition to the effect similar to the second embodiment. The S / N ratio of the optical signal is further improved, and the measurement accuracy of the neutron absorption position can be improved. This further improves the reliability of the device.

Although this embodiment is applied to the second embodiment, the present invention is not limited to this, and may be applied to the first embodiment, for example.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is based on any one of the above first to third embodiments, and is intended for two-dimensional measurement by expanding the measurement range of the sensor in a plane. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring device shown in FIG. 4 is applied to a device for carrying out two-dimensional measurement of neutrons, and the configuration of the sensor 1 is partially changed as compared with the above embodiments.

The sensor 1 is composed of a rectangular parallelepiped container 3 having a size capable of two-dimensional measurement, and a vertical direction at predetermined intervals in the horizontal direction (see the same figure) of a virtual surface for measurement arbitrarily set in the container 3. A plurality of wires 4 ... 4 stretched on the
4 is provided with a single optical fiber 5 which extends in the longitudinal direction in the vicinity of each of them and which is loaded in a U-shaped bent state at an intermediate position between two adjacent wires 4 and 4. An HV 11 is connected to each wire 4.

The signal processing system 2 includes photoelectric conversion devices 8 and 8 connected to both ends of the optical fiber 5. Other configurations are substantially the same as any one of the above-described respective embodiments, and therefore, illustration and description thereof will be omitted (however, in a signal processing device (not shown), an algorithm or the like regarding two-dimensional measurement is preset. ing).

In this monitoring device, when the signal processing system 2 performs the same processing as described above to obtain the light guide position of the optical fiber 5, the plurality of wires 4 ... 4 involved in the neutron absorption from the light guide position. The position of the neutron is identified and the data on the two-dimensional distribution of neutrons is acquired.

Therefore, according to this embodiment, the range of neutron measurement can be expanded two-dimensionally by providing one optical fiber for a plurality of wires, in addition to the same effects as the above-mentioned embodiments. Therefore, the sensor and the signal processing system can be simply constructed, and the two-dimensional neutron measuring device can be provided at a lower cost than before.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, a neutron source is assumed to be a nuclear reactor. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring device shown in FIG. 5 is a cylindrical reactor 1
The neutron n emitted from 2 to the surroundings is measured, and the sensor 1 and the signal processing system are partially changed as compared with the above embodiments.

The sensor 1 comprises an annular container 3 that covers the outside of the nuclear reactor 12 in the radial direction, a plurality of wires 4 ... 4, which are axially stretched in the container 3 at predetermined intervals in the circumferential direction. It is provided with one optical fiber 5 equivalent to that of the fourth embodiment, which passes through the respective positions near the wires 4. An HV 11 is connected to each wire 4.

In the signal processing system 2, photoelectric conversion devices 8 are connected to both ends of the optical fiber 5. Other configurations are substantially the same as any one of the above-described first to third embodiments, and therefore illustration and description thereof will be omitted (however, in the signal processing device not shown, neutron spatial output distribution measurement). The algorithm etc. are set in advance).

This monitoring device is generated in the nuclear reactor 12 by absorbing the neutrons n emitted from the inside of the nuclear reactor 12 to the outside in various directions by the wires 4 ... Measure the data on the spatial power distribution of neutrons.

Therefore, according to this embodiment, in addition to the same effects as the above-mentioned embodiments, the spatial output distribution of neutrons actually emitted around the reactor can be easily measured with a simple sensor and signal processing system. There are advantages.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described with reference to FIG. This embodiment is a modification of the fifth embodiment described above. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring apparatus shown in FIG. 6 has a part of the signal processing system 2 changed as compared with the fifth embodiment.
The sensor 1 has the same configuration as that of the fifth embodiment.

The signal processing system 2 is provided with a pulse counter (pulse counter) 13 in addition to the configuration of the second embodiment, and the counter 13 is interposed between the TDC 10 and the signal processor 9. The input end of the counter 13 is connected to the photoelectric conversion devices 8 and 8
Connected to each of.

The pulse counter 13 includes photoelectric conversion devices 8 and 8
And output signals of the TDC 10 are pulse-counted, and data regarding the count rate of the unit time is supplied to the signal processing device 9.

The signal processor 9 executes a preset neutron flux measurement algorithm or the like,
The data regarding the neutron flux emitted from the nuclear reactor 12 is measured based on the data regarding the count rate from the pulse counter 13.

Therefore, according to this embodiment, the fifth
In addition to the effect equivalent to that of the embodiment, the pulse count values of the output signals generated in the photoelectric conversion devices 8 and 8 and the TDC 10 are compared with each other to contribute to the neutron absorption caused by the background or malfunction. There is an advantage that the reliability of the neutron measurement is further enhanced because the non-pulse measurement can be excluded.

(Seventh Embodiment) Next, a seventh embodiment of the present invention will be described with reference to FIG. This embodiment is a modification of the fifth embodiment described above. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring apparatus shown in FIG. 7 has a part of the configuration of the signal processing system 2 compared to the fifth embodiment.

The signal processing system 2 includes, in addition to the configuration of the second embodiment, charge-sensitive amplifiers 14 ... 14 and a signal selection device 15, and wires 4 ... 4 are connected to the charge-sensitive amplifiers 14 respectively. 14 is connected to the signal selection device 15, and the output side of the signal selection device 15 is connected to the signal processing device 9.

The amplifiers 14 ... 14 amplify and detect the charges induced in the wires 4 ... 4 by the ionization phenomenon of the gas 6 caused by the neutron absorption. Here, the neutron is the wire 4 ...
Gas 6 along the track of the charged particle beam when absorbed by 4
And the gas 6 along the track is ionized into electrons and cations, and the electron group after the ionization is urged by the electric field due to the high voltage from the HV 11 to move inside the wires 4 ... As a result, electric charges are induced only in the specific wire 4 involved in neutron absorption. Therefore, if the induced charges are detected by the amplifiers 14 ... 14, the wire 4 involved in the neutron absorption can be identified by the presence or absence of the charges.

The signal selection device 15 selects the wire 4 involved in the neutron absorption among the plurality of wires 4 ... 4 in the container 2 based on the presence / absence information of the detection signals of the amplifiers 14 ... The selection information is supplied to the signal processing device 9.

When the signal processing device 9 performs the time difference measurement equivalent to the above to obtain the data regarding the neutron absorption position of the wire 4, the signal processing device 9 determines the wire 4 specified by the selection information from the signal selecting device 15 as a target. Signal processing of.

Therefore, according to this embodiment, the fifth
In addition to the same effect as the embodiment, there is an advantage that the measurement of the light guide position by the optical fiber is complemented, the load on the signal processing of the signal processing device is further reduced, and the position measurement accuracy is further enhanced.

(Eighth Embodiment) Next, an eighth embodiment of the invention will be described with reference to FIG. In the seventh embodiment described above, the presence or absence of an electric signal is determined by the signal selection device 15, but this embodiment measures the amount of the electric signal at the same time. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

In the monitoring device shown in FIG. 8, the configuration of the signal processing system 2 of the seventh embodiment is partially changed, and a signal selecting device 15 is provided.
14 and a signal measuring device 16 are inserted between the amplifiers 14 and 14 and the signal processing device 9.

The signal measuring device 16 is composed of, for example, a digital circuit equipped with a counter or the like, and is mainly counted in a charge amount or a unit time collected in a unit time based on an electric signal from each of the amplifiers 14 ... Data such as the pulse count value is measured and the data is supplied to the signal processing device 9.

The signal processing device 9 performs the time difference measurement in the same manner as described above to measure the data regarding the neutron absorption position of the wires 4 ... 4 and by executing the preset neutron flux measurement algorithm and the like. The electric signals from the signal measuring device 16 are integrated to simultaneously measure the data regarding the neutron flux.

Therefore, according to this embodiment, the fifth
In addition to the same effect as the embodiment, there is an advantage that not only the gas emission and the position measurement using the optical fiber but also the neutron flux measurement using the electric signal based on the ionization of the gas can be simultaneously performed.

(Ninth Embodiment) Next, a ninth embodiment of the present invention will be described with reference to FIG. In this embodiment, the shape and arrangement of a plurality of wires are devised. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

In the monitoring device shown in FIG. 9, the structure of the sensor 1 is partially changed as compared with the fifth embodiment.

The sensor 1 comprises a plurality of annular wires 4a ... 4a arranged in parallel at different axial positions in the container 2.
And this wire 4a ...
And a book optical fiber 5. H for wires 4 and 4a
V11 is connected.

The optical fiber 5 does not cover all the positions in the vicinity of the wires 4a ...
a ... 4a has a cross structure that crosses discretely at a predetermined interval, for example, is orthogonal to each other. The optical fiber 5 has two types of optical signals having different intensities, that is, a first optical signal OSa having a high optical intensity received near the intersection with the wires 4a ... 4a.
And the wires 4a ... 4 after being diffused or attenuated in the gas 6
The second optical signal O having a weak light intensity received at a position away from a
Optically transmits Sb. However, regarding the second optical signal OSb, since the self-propagation phenomenon of light due to the high electric field due to the HV11 is used, the light amount has almost no hindrance to the measurement.

The signal processing system 2 includes photoelectric conversion devices 8 and 8 connected to both ends of the optical fiber 5, respectively. Other configurations are substantially the same as any one of the sixth to eighth embodiments, and therefore the illustration and description thereof are omitted.

This signal processing system 2 includes photoelectric conversion devices 8 and 8
Converts each of the first and second optical signals OSa and OSb into an electric signal (electric pulse) and detects the electric signal, and an electric signal corresponding to both optical signals OSa and OSb is individually detected by a signal processing device (not shown). And the same time difference analysis as described above is performed to measure the neutron absorption position P of the wire. Thus, as the neutron absorption position P, the vicinity of the intersection of the wires 4a ... 4a and the optical fiber 5 and the intermediate position thereof can be accurately measured.

Therefore, according to this embodiment, since the optical fiber is provided so as to traverse the wire discretely, it is possible to further improve the estimation accuracy of the light guide position. In particular, by combining this embodiment with the seventh or eighth embodiment, there is an advantage that the accuracy of determination of the measurement position is further enhanced when the position calibration of the light emission signal by the ionization signal is performed.

(Tenth Embodiment) Next, the first embodiment of the present invention will be described.
The 0th embodiment will be described with reference to FIG. In this embodiment, the arrangement of wires is particularly devised by combining the above embodiments. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring device shown in FIG. 10 has a part of the configuration of the sensor 1 compared to the ninth embodiment.

The sensor 1 has, in the container 3, the wires 4 ... 4 similar to those in the fifth to eighth embodiments and the annular wires 4a ... 4a similar to those in the ninth embodiment, which are in a mesh shape. The optical fibers 5 are arranged in a stretched manner, and one optical fiber 5 similar to that in each of the above embodiments is arranged. Here, HV11 is connected to each wire 4, 4a. The optical fiber 5 is composed of wires 4, 4a stretched around the reactor 12 in a mesh pattern.
However, it is installed so as to pass in a specific direction, for example, a position near the wires 4 ...

The signal processing system 2 comprises photoelectric conversion devices 8 and 8 connected to both ends of the optical fiber 5. Other configurations are substantially the same as any one of the sixth to eighth embodiments, and therefore the illustration and description thereof are omitted.

The signal processing system 2 receives an optical signal from any one of the neutron absorbing positions of the wires 4 and 4a by using the optical fiber 5.
The data regarding the neutron absorption position P of the wires 4 and 4a is measured by being received by the photoelectric conversion devices 8 and 8 through and subjected to the same signal analysis processing (pulse waveform processing and the like) as described above.

Therefore, according to this embodiment, the ninth
In addition to the effects similar to those of the embodiment, there is an advantage that the analysis accuracy of data regarding the neutron absorption position can be further improved and the spatial output distribution of neutrons can be measured with more detailed accuracy.

(Eleventh Embodiment) Next, the first embodiment of the present invention will be described.
One embodiment will be described with reference to FIG. In each of the above-described embodiments, in addition to the emission signal based on the neutron absorption of the wire 3, the optical signal detected by the signal processing system may include other factors such as secondary particles such as γ-rays or electrons emitted from the nuclear reactor. It is assumed that the emission signal generated by the emission phenomenon of gas due to the charged particle beam containing the emission signal is included as a background component. In this embodiment, measures against noise related to such background components are devised. Here, the description of the components substantially equivalent to those of the above-described embodiment will be simplified or omitted.

The monitoring device shown in FIG. 11 is obtained by partially changing the configuration of the sensor 1 as compared with each of the above embodiments.

In the sensor 1, two optical fibers, that is, a first optical fiber 5a equivalent to the above is arranged in the vicinity of a plurality of wires 4 ... 4 and separated from the vicinity of the wires 4 ... The second optical fiber 5b is newly arranged at the above position. An HV 11 is connected to each wire 4. The sensor 1 optically transmits an optical signal OS1 mainly relating to neutron absorption via the first optical fiber 5a, and an optical signal OS2 including a background component not depending on neutron absorption via the second optical fiber 5b. Only optical transmission.

The signal processing system 2 includes first photoelectric conversion devices 8a and 8a connected to both ends of the first optical fiber 5a.
a and second photoelectric conversion devices 8b and 8b connected to both ends of the second optical fiber 5b. Since other configurations are substantially the same as those of the above-described embodiment, their illustration and description are omitted.

The signal processing system 2 includes two optical fibers 5
By obtaining the difference between the optical signals OS1 and OS2 of a and 5b, an optical signal in which the influence of the background not depending on the neutron absorption is almost removed is extracted, and based on the optical signal, the neutron absorption of the wire 4 is performed in the same manner as above. The position P is measured.

Therefore, according to this embodiment, in addition to the same effect as the above embodiment, the influence of noise due to the background can be almost eliminated, and the measurement accuracy of the neutron absorption position and the neutron flux can be further improved.

(Twelfth Embodiment) Next, the first embodiment of the present invention will be described.
2nd Embodiment is described based on FIG. In this embodiment, the radiation measuring system of the present invention is applied to an apparatus related to ionizing radiation measurement, for example, a radiation space output monitoring apparatus, instead of the apparatus related to neutron measurement described in the above embodiments. Here, the description of the constituent elements substantially equivalent to those of the above-described embodiments will be simplified or omitted.

The radiation space output monitoring apparatus shown in FIG.
It is arranged around a radiation generation source 17 that emits ionizing radiation including γ rays, electron rays, positron rays, proton rays, and other heavy charged particle rays. Some configurations have been changed.

That is, the sensor 1 is loaded with the wires 4b ... 4b to which the transmutation substance 7 is not applied. This is because when the ionizing radiation from the radiation generation source 17 passes near the wires 4b ... 4b, the proportional fluorescence phenomenon of the gas 6 occurs and strong emission occurs. Therefore, the sensor 1 receives the optical signal OS generated by the gas 6 in the vicinity of the wire 4 when receiving the ionizing radiation by the optical fiber 5 and optically transmits the signal.

The signal processing system 2 includes photoelectric conversion devices 8 and 8 connected to both ends of the optical fiber 5. Other configurations are substantially the same as any one of the above-described respective embodiments, and therefore, illustration and description thereof will be omitted. The signal processing system 2 measures the data relating to the ionizing radiation passage positions of the wires 4b ... 4b by performing the same signal processing as in the above-described respective embodiments.

Therefore, according to this embodiment, it is possible to exert the same effects as those of the above-mentioned respective embodiments with respect to ionizing radiation measurement, and it is possible to apply to a measuring device having a wide range of application. For example, it can be applied to a medical positron CT apparatus based on the CT method, a measuring apparatus that uses radiation to three-dimensionally analyze a sample to be measured, and the like.

Although the HV is provided in this embodiment, the present invention is not limited to this, and the HV may be omitted. This is because even if a high voltage is not applied to the wire, it is possible to obtain a light amount that hardly interferes with the measurement due to the gas emission phenomenon.

[0117]

As described above, according to the neutron measurement system according to the invention described in claims 1 to 15, in particular, the sensor is composed of a container in which a gas is enclosed, a wire coated with a transmutation substance, and an optical fiber. Therefore, the sensor and the signal processing system can be simply constructed, the load on the signal processing system can be significantly suppressed, and the entire apparatus can be provided at a relatively low cost.
This effect can be maximized especially when applied to a neutron space power distribution device or the like which is required to have a large size and radiation resistance around a nuclear reactor or the like.

According to the radiation measuring system of the sixteenth aspect of the present invention, since the sensor is composed of the container in which the gas is enclosed, the wire, and the optical fiber, the same effect as the above is exerted in the ionizing radiation measurement. For example, while utilizing the advantages of the CT method, it is possible to simply construct a sensor and a signal processing system suitable for a measuring device having improved versatility, and it is possible to provide the entire device at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring apparatus (with a neutron measurement system of the present invention) according to a first embodiment.

FIG. 2 is a schematic diagram showing an overall configuration of a neutron spatial power distribution monitoring device of a second embodiment.

FIG. 3 is a schematic diagram showing an overall configuration of a neutron spatial output distribution monitoring device of a third embodiment.

FIG. 4 is a schematic diagram showing an overall configuration of a neutron spatial output distribution monitoring device of a fourth embodiment.

FIG. 5 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device according to a fifth embodiment.

FIG. 6 is a schematic diagram showing the overall configuration of a neutron spatial power distribution monitoring device of a sixth embodiment.

FIG. 7 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device of a seventh embodiment.

FIG. 8 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device of an eighth embodiment.

FIG. 9 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device according to a ninth embodiment.

FIG. 10 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device of a tenth embodiment.

FIG. 11 is a schematic diagram showing the overall configuration of a neutron spatial output distribution monitoring device of an eleventh embodiment.

FIG. 12 is a schematic diagram showing an overall configuration of a radiation space output distribution monitoring apparatus (mounted with a radiation measurement system of the present invention) of a twelfth embodiment.

[Explanation of symbols]

 1 Sensor 2 Signal Processing System 3 Container 4 Wire 5 Optical Fiber (Optical Cable) 6 Gas 7 Nuclear Conversion Material 8 Photoelectric Converter 9 Signal Processor 10 TDC (Time Difference Analyzer) 11 HV (High Voltage Power Supply) 12 Nuclear Reactor (Neutron Generation) Source) 13 pulse counter 14 amplifier 15 signal selection device 16 signal measuring device 17 radiation source n neutron e charged particle OS optical signal

Claims (16)

[Claims] 1. A neutron measurement system comprising a sensor for detecting neutrons from a neutron source and a signal processing system for acquiring information on the neutrons from a detection signal of the sensor, wherein the sensor has the presence of charged particles. A container enclosing a gas that emits light below, and a wire that is disposed in this container and that has a nuclear transmutation substance that absorbs the neutrons and releases the charged particles when the neutrons are received in the container And the optical signal emitted by the gas in the vicinity of the wire in the presence of the charged particles emitted from the transmutation material when the neutron is absorbed by the wire. And an optical cable for optically transmitting the optical signal. Neutron monitoring system characterized by comprising a data acquisition means for acquiring data about neutron absorbing position of over. 2. The photoelectric conversion means for individually converting the optical signals of both ends of the optical cable into electric signals and detecting the electric signals, and the data acquisition means based on the electric signals detected by the photoelectric conversion means. The neutron measurement system according to claim 1, further comprising a position measurement unit that measures data regarding a neutron absorption position of the wire. 3. The position measuring means obtains data relating to a light amount difference between the respective optical signals at both ends of the optical cable, based on the electric signal detected by the photoelectric conversion means,
The neutron measurement system according to claim 2, which is a means for measuring data regarding a neutron absorption position of the wire from the data. 4. The position measuring means obtains data relating to an optical transmission time difference between the optical signals at both ends of the optical cable based on the electric signal detected by the photoelectric conversion means,
The neutron measurement system according to claim 2, which is means for measuring data regarding a neutron absorption position of the wire based on the data. 5. The high voltage power source for generating a high voltage for inducing proportional fluorescence due to self-propagation to an optical signal emitted from the gas, further comprising: the high voltage power source connected to the wire. The neutron measurement system according to claim 1. 6. The wire is a plurality of wires, the plurality of wires are arranged in the container, and the optical cable is a single optical cable.
2. A plurality of optical cables are arranged inside the container so as to pass in the vicinity of each of the plurality of wires.
The neutron measurement system according to any one of 1 to 5. 7. The neutron measurement system according to claim 6, wherein the position measuring means is means for measuring data relating to a two-dimensional neutron absorption position in the container based on an electric signal detected by the photoelectric conversion means. 8. The neutron source is a cylindrical reactor, the container is a cylindrical container having an inner diameter larger than the outer diameter of the reactor, and the container covers the periphery of the reactor. The neutron measurement system according to any one of claims 1 to 5, which is arranged at a position for receiving neutrons emitted from the nuclear reactor to the outside. 9. The neutron measurement system according to claim 8, wherein the position measuring means is means for measuring data regarding a neutron flux spatial distribution of the nuclear reactor based on an electric signal detected by the photoelectric conversion means. 10. The data acquisition means counts the pulse number of the optical signal for each neutron absorption event of the wire based on the electric signal detected by the photoelectric conversion means, and counts the pulse number per unit time. The neutron measurement system according to any one of claims 2 to 9, further comprising means for measuring data regarding a neutron flux absorbed in the wire based on a rate. 11. The data acquisition means detects an electric signal induced in each of the plurality of wires when a charged particle is emitted from the nuclear transmutation material, and the plurality of electric signals are detected based on each electric signal. The neutron measurement system according to any one of claims 5 to 9, further comprising a means for selecting a number of wires. 12. The data acquisition means detects an electric signal induced in each of the plurality of wires when the transmutation substance emits a charged particle, and integrates the electric signals to integrate the plurality of electric signals. The neutron measurement system according to any one of claims 5 to 9, further comprising means for measuring data relating to the amount of neutrons absorbed in each of the wires of the book. 13. The neutron measurement system according to claim 1, wherein the optical cable is arranged in the container in a state of being orthogonal to an axial direction of the wire. 14. The neutron measurement system according to claim 5, wherein the plurality of wires are arranged in a mesh in the container. 15. A separate optical cable passing through a position apart from the vicinity of the wire is arranged in the container.
15. The neutron measurement system according to any one of 1 to 14. 16. A radiation measuring system comprising a sensor for detecting ionizing radiation from a radiation source and a signal processing system for acquiring information on the ionizing radiation from a detection signal of the sensor, wherein the sensor is a wire. A container having a gas that emits light when the ionizing radiation passes and an optical cable that is arranged in the vicinity of the wire and receives an optical signal emitted by the gas in the vicinity of the wire and optically transmits the signal. The radiation measuring system, wherein the signal processing system comprises: a data acquiring unit that acquires at least data regarding a passing position of the ionizing radiation based on the optical signal optically transmitted by the optical cable.