JP2971358B2 - Radiation measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in nuclear facilities and the like, and can be measured with a small number of measuring devices while eliminating the need for a power source and an electronic circuit at a measuring place. The present invention relates to a radiation measurement device capable of performing high light multipoint measurement.

[0002]

2. Description of the Related Art In nuclear facilities such as a nuclear power plant, stationary radiation detectors are installed in places where measurement is required at a minimum in order to measure radiation dose.
In other places, a temporary radiation detector or a portable survey meter is used as needed.

A stationary or temporary radiation detector needs to supply power for a detector bias, a preamplifier, a signal transmission circuit, and the like, and further requires a signal transmission cable, a power cable, and the like.

A portable survey meter can be operated in a rechargeable manner. However, since a radiation manager or the like must carry the measurement with himself / herself to perform the measurement, operations such as reading and recording of numerical values are required. If the atmosphere is high, there is a problem of exposure, which is not preferable. In the case of this portable type, the work efficiency is low because it is necessary to perform round-trip measurements, and the dose is measured in advance in areas with extremely high doses or areas where humans cannot enter due to the problem of previous exposure. It is almost impossible to keep.

It is one solution to install a radiation measuring device at all measurement points required for radiation measurement. However, when the number of measurement points is increased, the measuring device, power supply device, signal Transmission cables, power cables, and the like must be laid, the number of auxiliary devices increases, the cost of laying and installation rises, and the cost of operation and maintenance also rises, making it practically difficult to implement this method.

For long-distance data transmission,
It is necessary to temporarily convert an electric signal into a digital signal or an optical signal and transmit the signal. An electronic circuit is required at a key point, and the problem of electromagnetic induction noise and the problem of a ground loop due to a difference in ground potential may occur.

Further, since an electronic circuit is attached near the detector, the reliability of the device is reduced due to the radiation effect of the semiconductor element in an area where the radiation dose is particularly high, so that the device cannot be used. There are many.

In view of the above, a power source and an electronic circuit are not required at the measurement site, and a scintillator is used for a detection unit, and light generated by the incidence of radiation is transmitted directly or indirectly to an optical fiber. Attempts have been made.
FIG. 39 shows a conventional light transmission type scintillation detector 23 used for such detection. Scintillator 10
Is covered with a reflector 9 and enclosed by a housing 8. The fluorescent fiber 24 is embedded therein and is fixed to the optical connector 13 attached to one end of the scintillator 10. An optical fiber 2 (or an aggregate of optical fibers) having a rod lens 12 (collimator lens) at its tip is attached to the optical connector 13. Fluorescence generated by absorption of the scintillation light is transmitted through the optical fiber 2 to the photoelectric conversion element 5. At this stage, the signal is converted into an electric signal and processed by the signal processing device 6 for the first time.

[0009]

With the optical transmission type scintillation detector 23 shown in FIG. 39, an electronic circuit and an electric cable are unnecessary at the measurement site, and a measurement system which is not affected by electromagnetic noise is constructed. . However, when measuring a plurality of points, using the measurement system of FIG. 39 causes a problem that a plurality of photoelectric conversion elements 5 and a plurality of signal processing devices 6 are required. That is, as shown in FIG. 40, a plurality of optical transmission type scintillation detectors 23 are arranged at each measurement location, and the transmission optical fiber 2
Is transmitted to the place where the measuring device is arranged. In this place, the number of photoelectric conversion elements 5 and signal processing devices 6 corresponding to the number of systems are required, and there is a problem that a large number of measurement devices are required in the measurement place.

In the light transmission type scintillation detector 23 shown in FIG. 39, a reflector is provided on one side of the fluorescent fiber 24. However, since it is practically difficult to perform perfect mirror reflection, one of the generated fluorescent light is used. The part may be wasted.
As a result, the signal-to-noise ratio of the signal is reduced, and as a result, the lower limit of the energy to be measured is increased.

Further, as another optical transmission type measuring system, a radiation dose distribution measuring method using a scintillating fiber has been developed as shown in FIG.
The scintillating fiber 25 is laid in the section to be measured, and the photoelectric conversion elements 5 are provided at both ends of the scintillating fiber 25, converted into electric signals, and processed by the signal processing device 6. With respect to this measurement method, some modifications have been proposed, such as using a quartz fiber with low light attenuation added.

However, when measuring the dose distribution of γ-rays in a nuclear facility or the like, this measuring method has various problems such as low detection efficiency and is difficult to be put into practical use.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned circumstances, and it is possible to perform measurement with a small number of measuring devices while eliminating the need for a power supply, an electronic circuit, and the like at a measuring place, and at a low cost. It is an object of the present invention to provide a radiation measuring apparatus capable of performing optical multipoint measurement with high radiation detection efficiency.

[0014]

To achieve this object, a radiation measuring apparatus according to claim 1 of the present invention is a radiation measuring apparatus for measuring radiation, wherein the radiation measuring apparatus simultaneously emits light according to received radiation. A plurality of scintillation detectors having two light outlets for emitting light, a plurality of scintillation detectors are connected in series at each of the two outlets, and the plurality of scintillation detectors are connected via the respective two light outlets. An optical fiber for transmitting the emitted light, photoelectric conversion means for converting the light transmitted via the optical fiber into an electric signal, and signal processing means for processing the electric signal to measure radiation. The photoelectric conversion means includes one photoelectric conversion element disposed at one end of an optical fiber connected in series, and another photoelectric conversion element disposed at the other end of the optical fiber connected in series. A reflector for reflecting the transmission light,
have. I have it.

Further, a radiation measuring apparatus according to claim 5 is
What is claimed is: 1. A radiation measuring apparatus for measuring radiation, comprising: a plurality of scintillation detectors having two light outlets that emit light simultaneously according to received radiation; and a plurality of scintillation detectors each having two outlets. And a plurality of optical fibers for transmitting light emitted from the plurality of scintillation detectors through each of the two outlets, and transmitting the light transmitted through the plurality of optical fibers respectively to an electric signal. And photoelectric conversion means for converting the electrical signal, and a signal processing means for measuring the radiation by signal processing the electrical signal,
The photoelectric conversion means includes one photoelectric conversion element disposed at one end of each of a plurality of optical fibers connected in parallel, and an optical conversion element disposed at each other end of the plurality of optical fibers connected in parallel. A reflector that reflects light transmitted through the fiber.

Further, a radiation measuring apparatus according to claim 12 is a plurality of scintillation detectors each having two light outlets for simultaneously emitting light according to received radiation,
An optical fiber connected to the plurality of scintillation detectors and transmitting light emitted through each of the two light outlets; photoelectric conversion means for converting light transmitted through the optical fiber into an electric signal; Signal processing means for signal processing of signals to measure radiation, wherein each of the scintillation detectors comprises a scintillator for emitting scintillation light in response to received radiation, and an optical Are arranged in close contact with each other, absorb the scintillation light, emit the corresponding fluorescent light, guide the light to both ends thereof, and transmit the light to the photoelectric conversion means via the optical fibers connected to the two light outlets. Along with
A wavelength shifter for passing fluorescence transmitted from another scintillation detector via an optical fiber.

Further, the radiation measuring apparatus according to claim 25 is provided with a scintillation detector comprising a scintillator which emits light upon incidence of radiation, and a wavelength shifter which absorbs the light and emits light of a longer wavelength. A radiation measurement device for measuring radiation based on emitted light, wherein the wavelength shifter is optically contacted by another wavelength shifter, and the other wavelength shifter is optically contacted by a scintillator.

Further, the radiation measuring apparatus according to claim 26 is provided with a scintillation detector comprising a scintillator which emits light upon incidence of radiation, and a wavelength shifter which absorbs this light and emits light of a longer wavelength. A radiation measurement device that measures radiation based on emitted light, wherein a transparent medium is mounted on an end surface of the scintillator, the wavelength shifter is optically contacted with another wavelength shifter, and the other wavelength shifter is Optically in contact with a transparent medium.

[0019]

As described above, in the first aspect, each scintillation detector is provided with two light outlets, and a plurality of scintillation detectors are connected in series at each of the two outlets. Therefore, the measurement can be performed with a small number of measurement devices without being affected by noise, while eliminating the need for a power source, an electronic circuit, and the like at the measurement location. In addition, it is possible to perform multi-point optical measurement at low cost and high radiation detection efficiency.

According to the present invention, each scintillation detector is provided with two light outlets, and a plurality of scintillation detectors are connected in parallel at each of the two outlets. Therefore, the measurement can be performed with a small number of measurement devices without being affected by noise, while eliminating the need for a power source, an electronic circuit, and the like at the measurement location. In addition, it is possible to perform multi-point optical measurement at low cost and high radiation detection efficiency.

Further, in the twelfth aspect, the light generated by the wavelength shifter is distributed and transmitted to both ends of the wavelength shifter at substantially the same time and at substantially the same light amount by the wavelength shifter itself serving as an optical waveguide. The action of being sent out to the optical fiber side and the light generated by the other scintillation detector enter one end of the wavelength shifter from one optical fiber side, propagate to the other end using the wavelength shifter as an optical waveguide, and again emit the other light. It also has the function of going out to the fiber side.

In the twenty-fifth and twenty-sixth aspects, another wavelength shifter is provided in addition to the wavelength shifter, while giving the wavelength shifter a function of transmitting light incident from one end face to the other end face. ing. Therefore, light having a wavelength that can propagate in the wavelength shifter can be injected from the outside as oblique light. Therefore, the light collection rate can be increased,
The S / N ratio of the detector can be improved.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical multi-point radiation measuring apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of a serial single type multi-point measuring system (corresponding to claim 1) . One group of optical waveguide type scintillation detectors is connected in series by a group of two divided first optical fibers, and is configured to form one ring as a whole. First
The photoelectric conversion elements 5 are respectively provided at both ends of the optical fiber 2 group, are converted into electric signals by these photoelectric conversion elements 5, and are processed by the signal processing device 6.

In this embodiment, two light outlets are provided at both ends of each of the plurality of scintillation detectors 1, and each of the plurality of scintillation detectors 1 is connected in a chain by the first optical fiber 2 group. Have been. The optical waveguide type scintillation detector 1 sends out its own light to two light outlets at both ends of the light guide, and light incident from the outside is propagated to the other light outlet.

Thus, it is possible to perform measurement with a small number of measuring devices while eliminating the need for a power supply, an electronic circuit, and the like at the measurement location, and perform low-cost multi-point measurement with high radiation detection efficiency.

In the series single type described above, the entrance and exit of the optical waveguide type scintillation detector 1 are provided at two locations (one set) at both ends. In this serial multiplexing type, a plurality of sets of light entrances are provided at both ends of the optical waveguide type scintillation detector 1. As shown in FIG. 2, a plurality of optical waveguide type scintillation detectors 1 are connected in series in a chain by a first optical fiber group 2, a second optical fiber group 3, and a third optical fiber group 4. . In the example shown in FIG. 2, three rings are formed as a whole. The photoelectric conversion elements 5 are provided at both ends of each of the first optical fiber group 2, the second optical fiber group 3, and the third optical fiber group 4.

Since the first optical fiber group 2, the second optical fiber group 3, and the third optical fiber group 4 each independently form a ring, signals of the optical fibers may be mixed. Absent. That is, the signal propagating through the first optical fiber 2 group is transmitted to the second optical fiber 3
It does not propagate through the group and the third optical fiber 4 group.

With this configuration, in this embodiment, it is possible to increase the magnitude of the light pulse obtained for one incident radiation, that is, the amount of light.

Regarding the series system, the arrival time difference at both ends, and the light amount difference method (corresponding to claim 3) In the case of a series single type multi-point measurement system and a series multiplex type multi-point measurement system, one optical waveguide type scintillation Detector 1
Light pulses emitted from both ends are sent out,
Each of them has an optical path leading to the photoelectric conversion element 5 and a propagation time delay and light attenuation due to passage through the plurality of optical waveguide type scintillation detectors 1. In addition, since the position itself of the scintillation detector in the part sensitive to radiation is discretized, "position blur" seen in distribution measurement using a scintillating fiber is extremely small.

In this embodiment, in the example shown in FIG. 1 or FIG. 2, an optical pulse generated for one event caused by the incidence of radiation on the scintillation detector 1 and sent out from both ends of the scintillation detector 1 Is received by the photoelectric conversion element 5 and the arrival time difference between these two light pulses is measured, or the light amount difference between these two light pulses is measured, and based on the arrival time difference or the light amount difference, the light pulse An identification means for identifying the scintillation detector 1 that is the source is provided. In the case where the difference is based on the light quantity, the light pulse is shaped into a waveform and converted into a light quantity, that is, a pulse height, so that the position of the optical waveguide type scintillation detector 1, which is the source of the pulse, is identified. I have.

Regarding the series system, the one-sided arrival time difference, and the light amount difference method (corresponding to claim 5) In this embodiment, as shown in FIG. 3 or 4, one of the photoelectric conversion elements 5 is removed, and this is removed. Where
A reflector 31 is provided. As a result, the signal arriving at the reflector 31 follows the optical fiber 2 group in the single type again as shown in FIG. 3, and again in the multiplex type as shown in FIG. The first optical fiber 2 group, the second optical fiber 3 group, and the third optical fiber 4 group are reversely traced,
The light reaches the photoelectric conversion element 5 provided at the other end.

In this case as well, the light pulse sent from a specific optical waveguide type scintillation detector 1 has an optical path reaching the photoelectric conversion element 5 and a plurality of optical waveguide type scintillation detectors, as in the previous embodiment. Propagation time delay and light attenuation due to passage through the scintillation detector 1 are generated.

When the scintillation detector 1 is identified, an optical pulse which is generated for one event caused by the incidence of radiation on the scintillation detector 1 and is sent out from one end of the scintillation detector 1, and the scintillation detector 1 is received by the photoelectric conversion element 5 from the other end and is reflected by the reflector 31 and reflected back through the scintillation detector 1 and the optical fiber 2. The arrival time difference between these two optical pulses is determined. There is provided an identification means for measuring or measuring the difference in light amount between these two light pulses and identifying the scintillation detector 1 which is the source of the light pulse based on the difference in arrival time or difference in light amount. In the case where the difference is based on the light quantity, the light pulse is shaped into a waveform and converted into a light quantity, that is, a pulse height, so that the position of the optical waveguide type scintillation detector 1, which is the source of the pulse, is identified. I have.

Parallel single type multi-point measurement system (corresponding to claim 5) When performing multi-point measurement, if the measurement points are located at completely different positions and the distance, direction, and path are different, In such a serial type, inconvenience and waste in laying the optical fiber may occur. In such a case, a parallel type multi-point measurement system as shown in FIG. 5 is used.

In this parallel single type multi-point measuring system, as shown in FIG. 5, a plurality of optical waveguide type scintillation detectors 1 are used.
Are installed at various places, and the light extracted from both ends of the scintillation detector 1 is two first optical fibers 2.
Thereby, each is guided to a pair of photoelectric conversion elements 5. The output of the photoelectric conversion element 5 is processed by the signal processing device 6.

With respect to the transmission distance of the first optical fiber 2, there is a difference between the lengths of the two first optical fibers 2 connected to each optical waveguide type scintillation detector 1. The difference between the lengths of the two first optical fibers 2 is equivalent to the difference between the optical path lengths, and is shown as an optical delay unit 7 in FIG. It should be noted that the delay can be adjusted not only by the difference in the length of the first optical fiber 2 group but also by other optical delay elements.

By setting the value of the delay time of the optical delay unit 7 arbitrarily within a range that can be processed by the signal processing device 6, the position of the scintillation detector 1, which is the source of the light pulse, is identified. Thus, regardless of the distance of the optical waveguide type scintillation detector 1 from the photoelectric conversion element 5, the position can be detected only by the delay time generated by the optical delay unit 7 for the optical waveguide type scintillation detector 1. If the optical delay unit 7 has the effect of attenuating light, the position can be identified based on the light amount difference described above.

A parallel multiplex type multi-point measuring system (corresponding to claim 6) Even in such a parallel type, not only one set of optical fibers is connected to each optical waveguide type scintillation detector 1, but also Two sets or two or more sets of optical fibers may be connected. FIG. 6 shows an optical waveguide type scintillation detector 1
Are shown by broken lines. With this configuration, in this embodiment, it is possible to increase the magnitude of the light pulse obtained for one incident radiation, that is, the amount of light.

In this embodiment, two optical fibers connected to each scintillation detector 1 in the example shown in FIG. 5 or FIG. The propagation time from each of the plurality of scintillation detectors 1 is set to be different according to the propagation time difference generated due to the difference in the length, and the arrival time difference or light amount difference detected by the pair of photoelectric conversion elements 5 is set. An identification means is provided for identifying the scintillation detector 1, which is the source of the light pulse, based on this. In the case where the difference is based on the light quantity, the light pulse is shaped into a waveform and converted into a light quantity, that is, a pulse height, so that the position of the optical waveguide type scintillation detector 1, which is the source of the pulse, is identified. I have.

Regarding the parallel system, the one-sided arrival time difference, and the light amount difference method (corresponding to claims 9 and 10) In this embodiment, one of the photoelectric conversion elements 5 in FIG. , A reflector 31 is provided. Thereby, this reflector 31
Again reaches the first group of optical fibers 2 in the case of FIG. 7 or the first signal in the case of FIG.
The optical fiber 2 group, the second optical fiber group 3, and the third optical fiber group (not shown) are reversely traced to reach the photoelectric conversion element 5 provided at the other end.

When the scintillation detector 1 is identified, an optical pulse which is generated in response to one event caused by the incidence of radiation on the scintillation detector 1 and is sent out from one end of the scintillation detector 1, and the scintillation detector A light pulse sent out from the other end of the light source 1 and reflected by the reflector 31 and traveling backward through the scintillation detector 1 and the optical fiber is received by the photoelectric conversion element 5, and the arrival time difference between these two light pulses is measured. Alternatively, there is provided an identification means for measuring a light amount difference between these two light pulses and identifying the scintillation detector 1 which is the source of the light pulse based on the arrival time difference or the light amount difference. In the case where the difference is based on the light quantity, the light pulse is shaped into a waveform and converted into a light quantity, that is, a pulse height, so that the position of the optical waveguide type scintillation detector 1, which is the source of the pulse, is identified. I have.

Wavelength selection method (corresponding to claim 9) When multi-pointing, a plurality of photoelectric conversion elements 5 are prepared,
A plurality of optical filters for selecting a wavelength band are provided in front of these photoelectric conversion elements 5.

A scintillation detector 1 that generates light pulses using these optical filters and photoelectric conversion elements 5
Is provided. That is, the wavelength of light transmitted by the optical fiber, that is, the emission center wavelength of the scintillation detector 1 in the case of scintillation light transmission, and the emission center wavelength of the phosphor used for condensing in the case of fluorescence transmission are different in advance. Regardless, the scintillation detector 1, which is the source of the pulse, can be identified based on the difference in the emission wavelength, regardless of the pulse arrival time or the difference in the amount of light. As a result, although the number of photoelectric conversion elements 5 increases, the position of the scintillation detector 1 at the source can be identified without increasing the cable itself.

Correction method 1 (corresponding to claim 10) As described above, the position of the scintillation detector 1 at the source can be identified from the arrival time difference or light amount difference of the light pulse. When the radiation dose in the atmosphere at the measurement point to be measured becomes high, the light pulses sent from the plurality of scintillation detectors 1 are brought close to each other, are superimposed, and an accidental erroneous counting operation is likely to occur. In this case, in order to complement both of the two information of the arrival time difference and the light amount difference, in this embodiment, a correction method 1 is proposed.

That is, when the source of the light pulse is to be identified, the position information identified from the information of the arrival time difference of the light pulse is predicted from the light path from the source to the photoelectric conversion element 5. If there is a certain difference or more between the light amount difference and the actually measured light amount difference, the signal erroneous detection means which does not count these two light pulse sets as not originating from the same scintillation detector 1 will be used. Is provided. For example, if the pulse height of a light pulse detected after the first light pulse is larger than that of the first light pulse with respect to two temporally consecutive light pulses, the light pulse is not counted as abnormal because of the optical path length. . Therefore, in this example,
In such a case, the accidental counting can be avoided.

Correction method 2 (corresponding to claim 11) In the wavelength selection method, the number of cables does not increase, but the number of photoelectric conversion elements 5 increases. However, the probability of contingency counting of the system decreases and the reliability increases. In practice, when multiple scintillation detector groups are included in the same center wavelength, or when the wavelength cannot be selected, the wavelengths are close to each other, or there is no suitable optical filter, wavelength separation / identification cannot be performed. When it is difficult, an arbitrary number of wavelengths cannot be finely divided and selected, so that the wavelengths are divided into several wavelength groups. In this case, within the specific wavelength group, correction can be performed using the above-described identification means based on the above-described arrival time difference and light amount difference, or correction can be performed using both the arrival time difference and the light amount difference described in the correction method 1. can do.

Basic Structure 1 of Optical Waveguide Scintillation Detector (Corresponding to Claim 12) FIG. 9 shows the basic structure of the optical waveguide scintillation detector 1 for multipoint measurement. The first optical fiber 2 is connected to both ends of the housing 8 by an optical connector 13. Inside the housing 8, the scintillator section 1
A reflector 9 is provided between the two. A wavelength shifter (fluorescent material) 11 penetrates through the center of the system of the scintillator unit 10 and is optically in contact with the end face of the second optical fiber 2.

The wavelength shifter 11 penetrates the system and light is extracted at both ends. In order to perform multi-point measurement using the difference in the propagation time of light and the difference in the amount of light, light pulses sent from both ends of the optical waveguide type scintillation detector 1 in response to one incident of radiation maintain synchronism. It is necessary. In order to distribute the generated fluorescence equally and use it efficiently, it is preferable to extract light at both ends of the wavelength shifter 11. In addition, since a plurality of optical fibers can be combined into a single cable, the amount of cables laid and the number of cables do not double because light is taken from both ends.

In the case of parallel connection, only the light from the optical waveguide type scintillation detector 1 is taken out, and it is not necessary to allow the light from the optical waveguide type scintillation detector 1 to pass. Therefore, the rod lenses 12 are used. It is also effective. However, when performing series-type multipoint measurement, it is necessary to pass and propagate an optical pulse sent from another optical waveguide type scintillation detector 1, so that the rod lenses 12 are unnecessary. . At this time, considering the light collection, it is appropriate that the diameters of the optical fibers connected to the core portion of the wavelength shifter are equal.

In order to satisfy these conditions, the wavelength shifter (phosphor) 11 needs to penetrate. Thus, light enters and exits from both ends, and apparently acts as one continuous optical waveguide when the first optical fiber 2 is connected.

That is, the fluorescent pulse emitted when the phosphor absorbs the scintillation light is distributed to both ends of the phosphor at substantially the same time and at substantially the same light amount by the phosphor itself serving as an optical waveguide. The action of being transmitted and sent out to the optical fiber side, and the light pulse generated by the other scintillation detector enters one end of the phosphor from the optical fiber side, propagates to the other end using the phosphor as an optical waveguide, and then returns to the optical fiber. It also has the function of going out to the fiber side.

The basic structure 2 of the optical waveguide type scintillation detector (corresponding to claim 13) Like the serial multiplex type multipoint measuring system (corresponding to claim 2),
When connecting a plurality of sets of optical fibers, the diameter of the wavelength shifter (phosphor) 11 is not increased, but the through hole of the scintillation detector 1 and the wavelength shifter (phosphor) 1
By increasing the number itself, a plurality of sets of optical fibers can be connected. In the case of a parallel multiplex type multi-point measurement system (corresponding to claim 5), the connection of a plurality of sets of optical fibers can be established by increasing the number of wavelength shifters or increasing the diameter of the wavelength shifter. Has been realized.

In the case of performing multi-point measurement, it is necessary that the optical fiber and the wavelength shifter continuously function as an optical waveguide, but the bundle type optical fiber and the large-diameter wavelength shifter satisfy this condition. Because there is nothing.

Generally, a thick wavelength shifter can be manufactured, but the optical fiber side can be formed only to a finite thickness or less in consideration of the bending radius and uniformity.

The core filling factor of the cross section of the bundle type optical fiber is at most several tens of percent, and a gap is generated between the cores. Therefore, even if the first optical fiber 2 is connected to both ends, it does not become a complete optical waveguide. Light that enters the wavelength shifter 11 from the first optical fiber 2 and enters the first optical fiber 2 again is partially lost due to the gap.

Basic structure 3 of optical waveguide type scintillation detector (corresponding to claim 14) When a plastic scintillator, a non-deliquescent inorganic scintillator, a ceramic scintillator, or the like is used as the scintillator, the scintillator is completely sealed and air is shut off. There is no necessity.

However, when a liquid scintillator and a deliquescent scintillator are used as the scintillator, it is necessary to maintain a sealed state for a long time in order to maintain the reliability of the scintillator.

In such a case, if a through hole is made for inserting the wavelength shifter (phosphor) 11 and further the wavelength shifter (phosphor) 11 is attached to the optical connector 13, the air in the scintillator section 10 is shut off. Difficult to completely enclose. This is because the resin-based wavelength shifter (phosphor) 11 and the housing 8 cannot be fused. In such a case, as shown in FIG. 10 or FIG. 11, the tubular optical window 14 made of a glass tube made of an optical glass material such as quartz glass is closely inserted into the through hole to be fused with the housing 8. Can be. The wavelength shifter (phosphor) 11 is inserted into the tubular optical window 14. With this configuration, the long-term stability and reliability of the scintillator can be improved.

The direction of the above-mentioned through-hole can be the direction of the cylinder axis as shown in FIG. 10 in the case of a normal column scintillator. However, if necessary, it can be oriented sideways as shown in FIG. It is preferable that the refractive index of the scintillator material and that of the tubular optical window 14 be as equal as possible.

Basic structure 4 of optical waveguide type scintillation detector (corresponding to claim 15) FIG. 12 shows an optical waveguide type scintillation detector of a type that can use a standard cylindrical scintillator 15 defined in the JIS standard. The basic structure is shown. The basic principle is the same as that of the optical waveguide type scintillation detector shown in FIG. However, as shown in FIG. 13, there is a slight difference in that an optical buffer 19 is provided so that the cylindrical scintillator 15 is mounted so as to be superimposed. That is, in the light buffer 19, a transparent medium (light pipe portion) 18 acting as a light pipe extends from the plate-shaped optical window 17 of the cylindrical scintillator 15, and the periphery of the transparent medium 18 is a reflector. The periphery of the reflector 9 is covered with a housing 8. The wavelength shifter 11 is inserted into a through hole formed in the transparent medium, and is connected to the first optical fiber 2 via the optical connector 13.

In this embodiment, preferably, the scintillator crystal 16, the plate-shaped optical window 17, and the transparent medium (light pipe) 18 of the light buffer 19 have the same refractive index, and the joint surface is It is preferable that they are completely adhered. In this embodiment, the light generated by the scintillator crystal 16 uniformly penetrates the transparent medium 18 and has a predetermined probability.
And the fluorescence emitted at this time is transmitted to the first optical fiber 2.

As described above, the use of the cylindrical scintillator 15 conforming to the JIS standard means that the scintillator itself has a high track record and high reliability in terms of manufacturing, low cost, detection efficiency as a radiation detector, direction and energy dependency. There are effects such as being guaranteed.

Basic structure 5 of optical waveguide type scintillation detector (corresponding to claim 16) As shown in FIG. 14, in this embodiment, two cylindrical scintillators are provided on both upper and lower surfaces of one optical buffer 19, respectively. 1
5 are mounted so as to be superposed. Thereby, the radiation detection efficiency is improved.

Method 1 for Extracting Light from Scintillator (Corresponding to Claim 17) There are many optical waveguide type scintillation detectors 1 shown in FIGS. 9 and 12 in which the wavelength shifter 11 can penetrate the system and extract light from both ends. When used for single measurement instead of point measurement, a reflector is provided at the light outlet at one end.
Thus, it can be used in the same manner as the conventional optical transmission type scintillation detector 23.

Method 2 for taking out light from scintillator (corresponding to claim 18) When the optical waveguide type scintillation detector 1 is used for a single measurement instead of a multipoint measurement, as shown in FIG. Light from the light outlets at both ends of the device 1 is guided to one common photoelectric conversion device 5 by the first optical fiber 2 and processed by the signal processing device 6. As a result, the fluorescence generated by the wavelength shifter 11 in the optical waveguide type scintillation detector 1 and sent to both ends of the detector 1 is efficiently guided to the photoelectric conversion element 5.

As described above, when the reflector is provided at the light exit at one end, it is difficult to achieve perfect specular reflection, so that some light loss cannot be avoided, but in this embodiment, Since the light at both ends of the detector 1 is received, the light amount of the signal is increased.

Method 3 for Extracting Light from Scintillator (Corresponding to Claim 19) When the optical waveguide type scintillation detector 1 is used for a single measurement instead of a multipoint measurement, as shown in FIG. Light at both ends of the device 1 is guided to a pair of photoelectric conversion elements 5 via two first optical fibers 2 and counted simultaneously. Thereby, a random noise component generated by the photoelectric conversion element 5 can be reduced. If there is a difference in length between the two first optical fibers 2, a similar coincidence method can be applied by performing delay time correction taking this into account.

FIG. 17 shows a case where light is guided from both ends of the detector 1 to a single photoelectric conversion element 5. An optical delay unit 7 is provided, and two signals are delayed and counted. That is, an optical pulse having the same amount of light as the loss received when passing through the optical delay unit 7 is counted as a true signal only when it reaches within the predicted delay time.

That is, when the light pulses at both ends of the scintillation detector are detected by the separate photoelectric conversion elements 5, coincidence counting is performed in which only the signals detected at the same time are significant light pulses. If there is a difference in the electric wavelength of the light from both ends, the coincidence is performed after correcting the time difference due to the length. For the signal that cannot be synchronized, the count as the noise component generated from the photoelectric conversion element 5 is calculated. Untargeted actions are taken. Thereby, the effective S / N ratio is improved.

Phosphor 1 (corresponding to claim 20) As shown in FIG. 16, the wavelength shifter 11 used in the optical waveguide type scintillation detector 1 is made of a fluorescent substance having an absorption spectrum that is well compatible with the spectrum of scintillation light. The glass, resin, and the like contained therein are processed into a cylindrical shape so as to be compatible with the optical fiber, and the entire surface is optically polished. In this embodiment, this wavelength shifter (phosphor)
Since the light pipe 11 needs to have a function of light propagation by total reflection as a light pipe, as shown in an enlarged manner in FIG. 19, the outer peripheral surface in the axial direction and the inner peripheral surface of the through hole of the scintillator section 10 are formed. It is preferable that a gap (for example, air, nitrogen atmosphere, or the like) lower than the refractive index of the wavelength shifter 11 is provided in the gap therebetween. Also, the gap is provided,
Not only between the inner peripheral surface of the through hole of the scintillator unit 10 but also between the inner peripheral surface of the transparent medium (light pipe unit) 18 of the optical buffer 19 and the wavelength shifter 11, or the inner peripheral surface of the optical glass tube And the wavelength shifter 11.

Phosphor 2 (corresponding to claim 21) A wavelength shift fiber in the form of an optical fiber using a core material as a wavelength shifter is commercially available, but this may be used as the wavelength shifter 11. In this case, since the wavelength shifting fiber is already provided with the cladding so as to totally internally reflect, it is not necessary to perform the role of the grading between the outer peripheral surface of the wavelength shifter 11 and the inner peripheral surface of the through hole. Therefore, as shown in FIG. 20, the space between the outer peripheral surface of the wavelength shifter 11 and the inner peripheral surface of the through hole is an optical gap as shown in FIG. 20 rather than a gap for reflecting light at the boundary surface and confining light to the scintillator side. It is preferable that the grease 20 is filled.

Block Dividing Structure (Corresponding to Claim 22) In the optical waveguide type scintillation detector 1, the scintillator section is divided into a shape that propagates light toward the wavelength shifter 11, and this divided unit, that is, The split scintillator 21 is formed in a light pipe shape around the wavelength shifter 11. The outer surfaces of these split scintillators 21 are polished, and a slight gap is provided between them so that they can be totally reflected inside, so that the entire shape is formed. As a result, the scintillation light is efficiently transmitted to the vicinity of the wavelength shifter 11, and finally, the amount of light is increased. As the shape of such a divided structure,
Various types may be used.

Examples of this divided structure are shown in FIGS. 21, 22 and 23. In the example of FIG. 21, the scintillator 21 is divided in the radial direction of the wavelength shifter 11 and arranged so as to surround the wavelength shifter 11. In the example of FIG.
A divided scintillator 21 formed in a cross shape is disposed around the wavelength shifter 11, and another divided scintillator 21 is filled so as to fill a gap between these cross-shaped scintillators 21.
Is arranged. In the example of FIG. 23, fan-shaped divided scintillators 21 are arranged in the radial direction of the wavelength shifter 11, and a large number of thin columnar (or thin prismatic) divided scintillators 21 are arranged between these fan-shaped divided scintillators 21. ing.

Block type (corresponding to claim 23) The transparent medium (light pipe section) 18 of the light buffer 19 shown in FIGS. 12 and 13 is also divided, and this divided unit, that is,
The divided transparent medium 22 is arranged around the wavelength shifter 11. These divided transparent media 22 are divided so as to propagate light toward the wavelength shifter, and the outer surfaces of the divided transparent media 22 are polished and slightly separated from each other so that they can be totally internally reflected. The gap is provided to form the entire shape. As a result, the scintillation light is efficiently transmitted to the vicinity of the wavelength shifter 11, and finally, the amount of light is increased. The shape of such a divided structure may be various.

FIG. 24 shows an example of such a divided structure.
In this example, a divided transparent medium 22 having a shape in which a cylinder is cut off by two slopes, and a fan-shaped divided transparent medium 22 disposed therebetween are provided.

In FIG. 25, the whole shape is formed by closely combining optical fibers so that the transparent medium 18 of the optical buffer 19 propagates light toward the wavelength shifter 11. A split transparent medium 22 in the form of an optical fiber having only a core wire or a light pipe surrounding the periphery thereof with an air gap is disposed at right angles to the wavelength shifter, and the upper and lower portions thereof are sandwiched between a pair of disc-shaped split transparent media 22. Thereby, the scintillation light is efficiently transmitted and collected in the vicinity of the wavelength shifter 11, and
Ultimately, the amount of light is increased.

Method of Adjusting Detection Efficiency (Corresponding to Claim 24) In this embodiment, a method of constructing a multipoint measuring system for adjusting the detection efficiency of radiation using the optical waveguide type scintillation detector 1 of the same size is described. Provided.

In the example shown in FIG. 26, when the optical waveguide type scintillation detectors 1 are connected in series, two adjacent detectors 1 are directly connected to each other, and the two detectors 1 are used without using the first optical fiber 2. The distance between the detectors 1 is zero.
Thereby, the scintillator is expanded substantially in the length direction, and the detection efficiency is increased.

In the example shown in FIG. 27, two optical waveguide type scintillation detectors 1 are stacked or adjacent to each other and connected by a short first optical fiber 2. This substantially increases the thickness or diameter of the scintillator and increases the detection efficiency.

In the example shown in FIG. 28, when a plurality of cores of a plurality of first optical fibers 2, a second optical fiber 3, and a third optical fiber 4 are laid, portions where the detection efficiency is unnecessary are , The optical waveguide type scintillation detector 1 is not connected. Thereby, the magnitude of the detection efficiency is adjusted.

Each of the three examples shown in FIGS. 26 to 28 may be used in combination. Also, in the case where the optical waveguide type scintillation detectors 1 are connected in parallel and multipoint measurement is performed, the examples shown in FIGS. 26 to 28 can be adopted. In particular, when the example corresponding to FIG. 28 is used, the optical fiber to which the optical waveguide type scintillation detector 1 is not connected does not need to be laid.

The basic structure 6 of the optical waveguide type scintillation detector (corresponding to claim 25) In the scintillation detector according to the above-described embodiment, S
In order to increase the / N ratio, it is necessary to increase the light collection efficiency of scintillation light. For that purpose, it is necessary to increase the diameter of the fluorescent substance or the fluorescent fiber to be used, or to increase the number of the fluorescent substance or the fluorescent fiber. As a result, it is necessary to increase the diameter of the optical fiber for signal transmission. However, in reality, the diameter of the fiber is also limited, so as shown in FIGS. 37 and 38,
A means for bundling a plurality of small diameter fibers is employed.

In the example shown in FIG. 37, a plurality of small-diameter phosphors or fluorescent fibers 11 penetrate through the scintillator 10, and a bundle of the small-diameter optical fibers 2
Are connected. In the example shown in FIG. 38, the large-diameter phosphor 11 penetrates the central axis of the cylindrical scintillator 10,
The bundled thin optical fiber 2 is connected to the end face of the phosphor 11.

However, an increase in the diameter of the optical fiber for signal transmission causes an increase in cost and an increase in the bending radius, which increases restrictions in laying cables, which is not practical.

It is theoretically possible to use a lens, a conical light guide, and the like in order to make light from a large-diameter phosphor or a fluorescent fiber enter a small-diameter optical fiber.
However, in this case, it is not possible to narrow down at an incident angle that can be transmitted to the optical fiber. Therefore, as a result, the loss is large and cannot be said to be a useful means.

Further, in the scintillation detector according to the above-described embodiment, when light is extracted from both ends of the detector and a plurality of detectors are connected in series to perform multipoint measurement, a plurality of detectors are required. It is necessary to completely connect the fluorescent material or the fluorescent fiber divided one by one to the optical fiber, and there are many problems in connection reproducibility and connection loss between the fluorescent fiber and the optical fiber.

From this point of view, the present embodiment uses a small-diameter transmission optical fiber while securing the continuity of the optical path by one-to-one connection between the phosphor or the fluorescent fiber and the optical fiber. It is an object of the present invention to provide a scintillation detector capable of increasing the amount of received light.

FIG. 29 shows an embodiment of a central waveguide type scintillator in which a wavelength shifter is arranged on the central axis of the system of the cylindrical scintillator. The first wavelength shifter 11a penetrating the central axis of the system of the scintillator 10 has a fibrous shape, that is, a cladding, and the outside thereof is of the same type as the first wavelength shifter 11a so as to be in optical contact with the first wavelength shifter 11a. Is surrounded by a second wavelength shifter 11b made of a fluorescent material. FIG. 30 shows a cross-sectional view of the central waveguide type scintillator. The first wavelength shifter 11a, the second wavelength shifter 11b, and the scintillator 10 are arranged concentrically and optically in close contact.

In the embodiment shown in FIG. 9, etc., only when the scintillation light passes through the central axis of the system of the cylindrical scintillator,
Fluorescence emission was taking place. However, as shown in FIG. 23, since the structure is provided with two wavelength shifters, a part of the light emitted by the second wavelength shifter 11b is used as the oblique light component of the first wavelength shifter 11a. 1
And transmitted by the optical fiber 2 connected to the end face. Even when the second wavelength shifter 11b is not provided, the scintillation light enters and propagates as an oblique light beam on the first wavelength shifter 11a. But,
Many of these have already undergone fluorescence conversion. Even a very small amount of scintillation light that has not undergone fluorescence conversion and has escaped absorption has a large transmission loss in the transmission optical fiber at that wavelength and cannot contribute to the finally obtained light amount. But,
In the present embodiment, the light converted into fluorescence by the second wavelength shifter 11b has a small transmission loss in the optical fiber 2, so that the final light amount can be increased.

FIG. 31 shows a specific example of the scintillation detector according to the present embodiment. A first wavelength shifter 11a penetrates the center of the scintillator 10 of the cylindrical optical waveguide type scintillation detector, and the outside is covered with a housing 8. The optical fiber for transmission 2 is connected to the input and output of light via the optical connector 13. The first wavelength shifter 11a used here is in the form of a plastic fiber. The outside of the first wavelength shifter 11a is surrounded by a second wavelength shifter 11b having no cladding material formed of a material containing the same kind of phosphor as the core material. The second wavelength shifter 11b has a cylindrical shape, and its inner wall is in contact with the first wavelength shifter 11a and its outer wall is in contact with the scintillator 10, but any gap is optically closely contacted with optical grease or the like. Need to be.

The scintillation light is subjected to fluorescence conversion by both the first wavelength shifter 11a and the second wavelength shifter 11b. Of the fluorescence generated in the first wavelength shifter 11a, the first half of the fluorescence is generated by the first wavelength shifter 11a. The light is transmitted to the end face of the wavelength shifter 11a. On the other hand, the fluorescent light generated in the second wavelength shifter 11b and corresponding to the oblique light ray component that can reach the first wavelength shifter 11b among the light that traverses the first wavelength shifter 11a is used as it is. The light is transmitted to the end face of the first wavelength shifter 11a without being absorbed, is incident on the optical fiber 2 connected via the optical connector 13, and is transmitted. Further, a part of the light that has reached the first wavelength shifter 11a without being absorbed by the second wavelength shifter 11b is absorbed and fluorescence-converted.

Conversely, the light incident from the optical fiber 2 side propagates inside the first wavelength shifter 11a and again from the other end via the optical connector 13 as in the embodiment of FIG. The optical fiber 2 is sent to the optical fiber 2 connected thereto. Therefore,
The function of transparent transmission to the outside operates in the same manner as in the embodiment shown in FIG. The second wavelength shifter 11b does not participate in the transmission function at all, but only contributes to the light collection rate of the scintillation light generated inside.

Basic Structure 7 of Optical Waveguide Scintillation Detector (Corresponding to Claim 26) FIG. 32 shows an embodiment of a light collecting adapter for end face waveguide type to be mounted on a general cylindrical scintillator. A first wavelength shifter 11a and a second wavelength shifter 11b are provided in a transparent medium 18 made of acrylic or glass or the like.
Is penetrating. The circular cross section of the transparent medium 18 is a scintillation light incident surface 41. This uses the scintillation light incident surface 41 in close contact with the light extraction surface of a normal cylindrical scintillator. Since the light collecting principle itself is the same, the same effect as that obtained in the case of FIG. 29 is obtained. The effect is obtained.

FIG. 33 shows a specific example of an end-face waveguide type light collecting adapter according to this embodiment. First wavelength shifter 11a
The second wavelength shifter 11b and the second wavelength shifter 11b are the same as those in FIG. 31, but the periphery of the second wavelength shifter 11b is a transparent medium 18 made of acrylic or glass in the present embodiment. Transparent medium 18 and second wavelength shifter 11b
Is in close optical contact with optical grease or the like.

The end surface of the cylindrical scintillator 10 is optically densely contacted with the scintillation light incidence surface 41 by optical grease or the like, and the scintillation light enters the transparent medium 18. From here on, the process is
This is the same as in the case of FIG. Therefore, also in this embodiment, the same effects as those in the embodiments of FIGS. 29 to 31 can be obtained.

Basic Structure 8 of Optical Scintillation Detector (Corresponding to Claims 27 and 28) FIG. 34 shows a multiple embodiment in which a wavelength shifter having no cladding portion is provided on the central axis of the system of a cylindrical scintillator. In this case, the first penetrating the system central axis of the scintillator 10
In order to establish transmission by total reflection in the wavelength shifter 11a, the inert gas 42 such as air or nitrogen needs to be clad. The outside thereof is surrounded by a second wavelength shifter 11b made of the same material as the first wavelength shifter 11a with a gap therebetween. Thereby, the same effect as in the case of FIGS. 29 to 31 can be obtained. This embodiment can also be applied to the end-face waveguide type light collecting adapter shown in FIGS.

Basic Structure 9 of Optical Scintillation Detector (Corresponding to Claims 29 and 30) FIGS. 35 and 36 show an embodiment in which a plate-like wavelength shifter is provided. FIG. 35 shows a case of the central waveguide type in which the first wavelength shifter 11a penetrates the center of the system of the cylinder, and FIG.
This figure shows a case of an end-face waveguide type light collecting adapter mounted on a normal cylindrical scintillator.

In FIG. 35, the cylindrical scintillator 10 is divided in half in the vertical direction, and the second wavelength shifter 11 has a plate shape.
b is in optical close contact with the divided cylindrical scintillator 10 with an inert gas interposed therebetween. The cylindrical scintillator 10 may be divided into four parts as shown by the broken lines in FIG. 35, or may be further divided into more parts.

When the first wavelength shifter 11a has cladding, the end face of the second wavelength shifter 11b is in optical close contact with the first wavelength shifter 11a.
The fluorescence generated by the plate-shaped second wavelength shifter 11a is transmitted toward the plate-shaped end face of the second wavelength shifter 11b,
The light enters the first wavelength shifter 11a from the end face, and a part of the light propagates through the first wavelength shifter 11a as an oblique ray component. As a result, the same effect as in the embodiment of FIGS. 29 to 31 can be obtained.

Although FIG. 36 is also an end-face waveguide type light-collecting adapter, a plate-shaped second wavelength shifter is formed as in the case of FIG.

Basic Structure 10 of Optical Waveguide Scintillation Detector (Corresponding to Claims 31 and 32) When the flat second wavelength shifter shown in FIGS. 35 and 36 is provided, the first wavelength Shifter 11a
Does not have a cladding portion, the end face of the first wavelength shifter 11a and the end face of the second wavelength shifter 11b are not optically adhered to each other.
An inert gas such as air or nitrogen is interposed in the gap between a and 11b. Thereby, the same effect as that shown in FIGS. 29 to 31 can be obtained.

The present invention is not limited to the above-described embodiment, but can be variously modified.

[0104]

As described above, in claim 1, each scintillation detector is provided with two light outlets,
A plurality of scintillation detectors are connected in series at each of its two outlets. Therefore, the measurement can be performed with a small number of measurement devices without being affected by noise, while eliminating the need for a power source, an electronic circuit, and the like at the measurement location. In addition, it is possible to perform multi-point optical measurement at low cost and high radiation detection efficiency.

Further, also in claim 5, each scintillation detector is provided with two light outlets, and a plurality of scintillation detectors are connected in parallel at each of the two outlets. Therefore, while eliminating the need for a power supply, electronic circuit, etc. at the measurement location, it is not affected by noise,
Can be measured with a small number of measuring devices. In addition, it is possible to perform multi-point optical measurement at low cost and high radiation detection efficiency.

Further, in the twelfth aspect, the light generated by the wavelength shifter is sent out to the optical fiber side almost simultaneously to both ends of the wavelength shifter by the wavelength shifter itself serving as an optical waveguide. The light generated by the scintillation detector is incident on one end of the wavelength shifter from one optical fiber side, propagates to the other end using the wavelength shifter as an optical waveguide, and returns to the other optical fiber side. I have.

Further, according to the twenty-fifth and twenty-fifth aspects, another wavelength shifter is provided in addition to the wavelength shifter while giving the wavelength shifter a function of transmitting light incident from one end face to the other end face. ing. Therefore, light having a wavelength that can propagate in the wavelength shifter can be injected from the outside as oblique light. Therefore, the light collection rate can be increased,
The S / N ratio of the detector can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a single series type multipoint measurement type.

FIG. 2 is a schematic diagram showing a configuration of a serial multiplex type multipoint measurement system.

FIG. 3 is a schematic diagram showing a configuration of a one-sided arrival time difference and a light amount difference method in a serial single type.

FIG. 4 is a schematic diagram showing a configuration of a one-sided arrival time difference and light amount difference method in a serial multiplexing type.

FIG. 5 is a schematic diagram showing a configuration of a parallel single type multi-point measurement system.

FIG. 6 is a schematic diagram showing a configuration of a parallel multiplex type multipoint measurement system.

FIG. 7 is a schematic diagram showing a configuration of a one-sided arrival time difference and a light amount difference method in a parallel single type.

FIG. 8 is a schematic diagram showing a configuration of a one-sided arrival time difference and light amount difference method in a parallel multiplexing type.

FIG. 9 is a schematic view showing a structure of an optical waveguide type scintillation detector.

FIG. 10 is a perspective view of a housing of the optical waveguide type scintillation detector and a tubular optical window.

FIG. 11 is a perspective view of a housing of the optical waveguide type scintillation detector and a tubular optical window.

FIG. 12 is a schematic diagram showing a structure of an optical waveguide type scintillation detector provided with an optical buffer.

FIG. 13 is a perspective view of a first example of a cylindrical scintillator and a light buffer.

FIG. 14 is a perspective view of a second example of the cylindrical scintillator and the optical buffer.

FIG. 15 is a schematic diagram of a measurement device in which two optical fibers are connected to a common photoelectric conversion device when the optical waveguide type scintillation detector is used for a single measurement instead of a multipoint measurement.

FIG. 16 is a schematic diagram of a measurement device in which two optical fibers are connected to two photoelectric conversion devices, for example, when the optical waveguide type scintillation detector is used for single measurement instead of multipoint measurement.

FIG. 17 shows a measurement in which two optical fibers are connected to a common photoelectric conversion device and an optical delay unit is provided, for example, when the optical waveguide type scintillation detector is used for single measurement instead of multipoint measurement. FIG.

FIG. 18 is a schematic view showing a portion of a wavelength shifter of the scintillation detector.

FIG. 19 is an enlarged schematic diagram illustrating the wavelength shifter of FIG. 18;

FIG. 20 is an enlarged schematic view of the wavelength shifter of FIG. 18, showing an example in which an optical oil or the like is filled.

FIG. 21 is a perspective view of a first example showing a divided scintillator.

FIG. 22 is a perspective view of a second example showing a divided scintillator.

FIG. 23 is a perspective view of a third example showing a divided scintillator.

FIG. 24 is a perspective view and an exploded perspective view of a first example showing a divided optical buffer.

FIG. 25 is a perspective view and an exploded perspective view of a second example showing a divided optical buffer.

FIG. 26 is a schematic view of a first example of a method for adjusting the detection efficiency.

FIG. 27 is a schematic view of a second example of a method for adjusting the detection efficiency.

FIG. 28 is a schematic view of a third example of the method for adjusting the detection efficiency.

29A and 29B show a scintillator and a wavelength shifter of a basic structure 6 of the optical waveguide type scintillation detector, wherein FIG. 29A is a perspective view and FIG. 29B is a plan view.

30 is a sectional view of the scintillator and the wavelength shifter shown in FIG.

FIG. 31 is a schematic view of a basic structure 6 of an optical waveguide type scintillation detector.

32 shows a scintillator and a wavelength shifter of a basic structure 7 of the optical waveguide type scintillation detector, (a) is a perspective view, and (b) is a plan view.

FIG. 33 is a schematic view of a basic structure 7 of an optical waveguide type scintillation detector.

FIG. 34 is a plan view of a scintillator and a wavelength shifter of the basic structure 8 of the optical waveguide type scintillation detector.

FIG. 35 is a perspective view of a central waveguide type scintillator and a wavelength shifter of the basic structure 9 of the optical waveguide type scintillation detector.

FIG. 36 is a perspective view of an end surface guided scintillator, a wavelength shifter, and a transparent medium of a basic structure 9 of the optical waveguide type scintillation detector.

FIG. 37 is a perspective view of an example of a scintillator and a wavelength shifter.

FIG. 38 is a perspective view of another example of the scintillator and the wavelength shifter.

FIG. 39 is a schematic view of a conventional radiation measurement device.

FIG. 40 is a schematic view of a conventional multipoint measuring device.

FIG. 41 is a schematic view of a conventional distribution measuring device.

[Explanation of symbols]

 Reference Signs List 1 optical scintillation detector 2 first optical fiber 3 second optical fiber 4 third optical fiber 5 photoelectric conversion element (photoelectric conversion means) 6 signal processing device (signal processing means) 7 optical delay unit 9 reflector Reference Signs List 10 scintillator part (scintillator) 11 wavelength shifter (phosphor) 11a first wavelength shifter (wavelength shifter) 11b second wavelength shifter (different wavelength shifter) 14 tubular optical window 15 cylindrical scintillator 16 scintillator crystal 17 plate optical Window 18 Transparent medium (light pipe) 19 Optical buffer 20 Optical grease (optical oil) 21 Split scintillator 22 Split buffer

Claims (32)

(57) [Claims] 1. A radiation measuring apparatus for measuring radiation, comprising: a plurality of scintillation detectors having two light outlets for simultaneously emitting light according to received radiation; and a plurality of scintillation detectors. Each of the two outlets is connected in series, and two or more scintillation detectors are connected in series.
An optical fiber for transmitting the light emitted through the two light outlets, a photoelectric conversion means for converting the light transmitted via the optical fiber into an electric signal, and measuring the radiation by processing the electric signal Signal processing means, wherein the photoelectric conversion means is arranged at one end of an optical fiber connected in series, and at the other end of the optical fiber connected in series, A radiation measuring device, comprising: a reflector that reflects light transmitted through an optical fiber. 2. A scintillation detector comprising a plurality of sets of light outlets, each set comprising two outlets, wherein a plurality of scintillation detectors are connected in series with each of the plurality of sets of light outlets. The radiation measuring apparatus according to claim 1, further comprising a plurality of sets of optical fibers each transmitting light emitted from the plurality of scintillation detectors through each of the plurality of sets of light outlets. 3. The photoelectric conversion means has two photoelectric conversion elements provided at both ends of an optical fiber connected in series, and two light emitted from two light outlets of each scintillation detector. Is received by the two photoelectric conversion elements,
Identification means for measuring the difference between the arrival times of these two lights or measuring the difference in the amount of light between these two lights and identifying the scintillation detector which is the source of the light based on the difference in the arrival time or the difference in the amount of light 3. The method according to claim 1, further comprising:
A radiation measuring device according to item 1. 4. A light emitted from one light outlet of each scintillation detector and transmitted by an optical fiber, and the light emitted from the other light outlet and reflected by the reflector is reflected by the scintillation detector and the optical fiber. And the light transmitted in reverse is received by the one photoelectric conversion element,
Identification means for measuring the difference between the arrival times of these two lights or measuring the difference in the amount of light between these two lights and identifying the scintillation detector which is the source of the light based on the difference in the arrival time or the difference in the amount of light The radiation measuring apparatus according to claim 3, further comprising: 5. A radiation measuring apparatus for measuring radiation, comprising: a plurality of scintillation detectors having two light outlets for simultaneously emitting light according to received radiation; and a plurality of scintillation detectors. Each of the two outlets is connected in parallel, and each of two scintillation detectors
A plurality of optical fibers for transmitting the light emitted through one of the outlets; photoelectric conversion means for converting the light transmitted respectively via the plurality of optical fibers into an electric signal; And a signal processing means for measuring radiation. The photoelectric conversion means comprises: one photoelectric conversion element disposed at one end of each of a plurality of optical fibers connected in parallel; And a reflector disposed at each other end of the plurality of optical fibers and reflecting light transmitted through the optical fibers. 6. Each scintillation detector has a plurality of sets of light outlets, one set comprising two outlets, and the plurality of scintillation detectors are connected in parallel at each of the plurality of sets of light outlets. The radiation measuring apparatus according to claim 5, further comprising a plurality of sets of optical fibers each transmitting light emitted from the plurality of scintillation detectors through each of the plurality of sets of light outlets. 7. The photoelectric conversion means has two photoelectric conversion elements provided at both ends of a plurality of optical fibers connected in parallel, and is connected to two light outlets of each scintillation detector. The difference in the length of the optical fiber is given to give a propagation time difference,
Thereby, the propagation times from the two light outlets of each scintillation detector are made different, and the two lights emitted from the two light outlets of each scintillation detector are received by the two photoelectric conversion elements,
Identification means for measuring the difference between the arrival times of these two lights or measuring the difference in the amount of light between these two lights and identifying the scintillation detector which is the source of the light based on the difference in the arrival time or the difference in the amount of light 7. The method according to claim 5, further comprising:
A radiation measuring device according to item 1. 8. The optical fiber connected to the two light outlets of each scintillation detector has a different length to provide a propagation time difference, whereby the propagation from the two light outlets of each scintillation detector is provided. At different times, the light emitted from one light outlet of each scintillation detector and transmitted by the optical fiber and the light emitted from the other light outlet and reflected by the reflector are reflected by the scintillation detector and the optical fiber. And the light transmitted in the opposite direction is received by the one photoelectric conversion element, and the arrival time difference between these two lights is measured, or the light amount difference between these two lights is measured, and the arrival time difference or The radiation measuring apparatus according to claim 7, further comprising an identification unit configured to identify a scintillation detector that is a light source based on the light amount difference. 9. The apparatus according to claim 1, further comprising identification means for setting a wavelength of the light transmitted by the optical fiber to be different in advance, and for identifying a scintillation detector which is a source of the emitted light according to a difference in emission wavelength. The radiation measuring apparatus according to any one of claims 2, 5, and 6. 10. When the source of emitted light is to be identified, position information identified from information on the difference in arrival time of light is predicted from the path of light from the source to the photoelectric conversion element. If there is a certain difference or more between the light amount difference and the actually measured light amount difference, it is further provided with a signal erroneous detection means which does not count these two lights as not originating from the same scintillation detector. Claims 3, 4,
The radiation measurement device according to any one of claims 7 and 8. 11. A means for identifying a scintillation detector, which is a source of emitted light, based on a difference in emission wavelength, based on a difference in arrival time and a difference in light amount between two lights received by wavelength. 10. The radiation measuring apparatus according to claim 9, further comprising the signal erroneous detection unit based on a difference in arrival time and a difference in light amount. 12. A plurality of scintillation detectors each having two light outlets for simultaneously emitting light in response to received radiation, and a plurality of scintillation detectors connected to the plurality of scintillation detectors and emitted through each of the two light outlets. An optical fiber that transmits the transmitted light, a photoelectric conversion unit that converts the light transmitted through the optical fiber into an electric signal, and a signal processing unit that processes the electric signal to measure radiation. A scintillator that emits scintillation light in response to received radiation; and a scintillator that is disposed in optical contact with the scintillator, absorbs the scintillation light and emits fluorescent light in accordance with the scintillation light. And the light is guided to both ends of itself and transmitted to the photoelectric conversion means via the optical fibers connected to the two light outlets, and is also transmitted to another system. And that the radiation measurement device comprising a wavelength shifter for passing the fluorescence transmitted through the optical fiber from the switch configuration detector. 13. The radiation measuring apparatus according to claim 12, wherein a plurality of wavelength shifters are arranged in one scintillator and connected to a plurality of optical fibers. 14. A through hole is formed in said scintillator,
13. The optical glass tube is inserted into the through hole, and the wavelength shifter is inserted into the optical glass tube.
Or the radiation measuring device according to 13. 15. The scintillation detector according to claim 12, wherein the scintillation detector has a transparent medium that is optically contacted with the scintillator and guides scintillation light from the scintillator to a wavelength shifter. Radiation measurement device. 16. The radiation measuring apparatus according to claim 15, wherein said scintillation detector has another scintillator disposed on the other side of said transparent medium and in optical contact therewith. 17. The scintillation detector according to claim 12, wherein the scintillation detector has a reflector disposed at one of the light outlets, whereby light is emitted only from the other light outlet.
The radiation measurement device according to any one of the above. 18. A light source according to claim 12, wherein light from two light outlets of said scintillation detector is guided to one common photoelectric conversion element by two optical fibers and processed by a signal processing device. The radiation measurement device according to claim 1. 19. When the light emitted from the two light outlets of the scintillation detector is detected by the two photoelectric conversion elements, a coincidence count is performed in which only signals detected at the same time are significant light pulses, or If there is a difference in the propagation length of light from both ends of the scintillator, the time difference due to the length is corrected and the coincidence is performed. For signals that cannot be synchronized, the noise component generated from the photoelectric conversion element The radiation measurement apparatus according to any one of claims 12 to 16, wherein the radiation measurement apparatus is not a counting target. 20. An air gap is provided between the outer peripheral surface of the wavelength shifter and the inner peripheral surface of the through hole of the scintillator, the inner peripheral surface of the transparent medium, or the inner peripheral surface of the optical glass tube. 1
20. The radiation measuring device according to any one of 2 to 19. 21. When the wavelength shifter is an optical fiber-shaped wavelength shifter fiber, an outer peripheral surface of the wavelength shifter fiber, an inner peripheral surface of a through hole of a scintillator, an inner peripheral surface of a transparent medium, or an optical glass tube. 2. An optical oil is filled between the inner peripheral surface and the inner peripheral surface.
20. The radiation measuring device according to any one of 2 to 19. 22. A scintillator or a transparent medium is divided into shapes so as to propagate light toward a wavelength shifter, and a gap is provided between the divided ones so that light can be totally internally reflected, The whole shape is constituted by combining these divided parts.
The radiation measurement device according to any one of claims 1 to 7. 23. A radiation as claimed in any one of claims 12 to 19, wherein the overall shape is constructed by tightly combining optical fibers such that the transparent medium propagates light towards the wavelength shifter. measuring device. 24. An arrangement for connecting said scintillation detectors at the time of multipoint measurement, an arrangement for superimposing or adjoining scintillation detectors connected in series or in parallel by optical fibers, and an arrangement for measuring locations. 24. An arrangement in which an optical fiber in which a scintillation detector is inserted and an optical fiber in which a scintillation detector is not inserted are provided, or the arrangement is a combination of these arrangements. The radiation measuring device according to the paragraph. 25. A scintillation detector comprising a scintillator which emits light upon incidence of radiation and a wavelength shifter which absorbs the light and emits light of a longer wavelength, and measures the radiation based on the emitted light. A radiation measuring device, wherein the wavelength shifter is optically contacted by another wavelength shifter,
A radiation measurement device in which this other wavelength shifter is in optical contact with the scintillator. 26. A scintillation detector comprising a scintillator which emits light upon incidence of radiation and a wavelength shifter which absorbs the light and emits light of a longer wavelength, and measures the radiation based on the emitted light. A radiation medium, wherein a transparent medium is mounted on an end face of the scintillator, the wavelength shifter is optically in contact with another wavelength shifter, and the another wavelength shifter is optically in contact with the transparent medium. Radiation measurement device. 27. The radiation measuring apparatus according to claim 25, wherein a gas is interposed in a gap between said wavelength shifter and said another wavelength shifter. 28. The radiation measuring apparatus according to claim 26, wherein a gas is interposed in a gap between said wavelength shifter and said another wavelength shifter. 29. The scintillator according to claim 25, wherein said wavelength shifter is optically contacted with another plate-shaped wavelength shifter, and said two wavelength shifters are embedded in said scintillator in optical contact. Radiation measurement device. 30. A transparent medium is mounted on an end face of said scintillator, said wavelength shifter is brought into optical contact with another plate-shaped wavelength shifter, and these two wavelength shifters are brought into optical contact with said transparent medium. 27. It is buried in a state
A radiation measuring device according to item 1. 31. The radiation measuring apparatus according to claim 29, wherein a gas is interposed in a gap between the wavelength shifter and the another wavelength shifter. 32. The radiation measuring apparatus according to claim 30, wherein a gas is interposed in a gap between the wavelength shifter and the another wavelength shifter.