JP2017049226A - Radioactive ray detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactive ray detection device that can attain downsizing of a device as a whole, and lightweight thereof.SOLUTION: A radioactive ray detection device (10) is configured by comprising: a solid scintillator (11) that is excited by an entering radioactive ray to emit scintillation light; a wavelength conversion fiber (12) that is arranged along the solid scintillator, and causes the entered scintillation light to be propagated in either end direction; and a detector (13) that is connected to each of either end of the wavelength conversion fiber to detect the scintillation light. The detector is composed of a plurality of avalanche photodiodes (13a).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radiation detection apparatus that detects radiation using a scintillator.

  Conventionally, a radiation detection apparatus equipped with a scintillator having a large area (for example, A3 size) is known, and such a radiation detection apparatus is used in a dust monitor or a gate monitor. In such a radiation detection apparatus, for example, a structure disclosed in Patent Document 1 is employed. The radiation detection apparatus of Patent Document 1 is configured with a plate-shaped radiation detection unit including a scintillator and a radiation measurement unit including a photomultiplier tube as separate bodies.

  In Patent Document 1, the radiation detection unit includes a plurality of optical fibers provided on one surface of the scintillator. When radiation from the radioactive material reaches the scintillator in the radiation detection unit, scintillation light is generated. Then, the scintillation light reaches the optical fiber, wavelength conversion or the like is performed, and it reaches the photomultiplier tube of the radiation measuring unit to detect the radiation. In such a radiation detection unit, since the outer diameter of the optical fiber is about 1 mm, it is possible to reduce the thickness while forming a wide light receiving surface.

Japanese Patent No. 4069881

  However, in the radiation detection apparatus as in Patent Document 1, the diameter of the photomultiplier tube is as large as about 1 inch, and even if the radiation detection unit is thinned, the separate radiation measurement unit is large and heavy. Become. Therefore, even if it sees as a whole radiation detection apparatus, there exists a problem of enlargement and weight increase.

  The present invention has been made in view of this point, and an object of the present invention is to provide a radiation detection apparatus capable of reducing the size and weight of the entire apparatus.

  The radiation detection apparatus of the present invention includes a solid scintillator that emits scintillation light when excited by incident radiation, and at least one fiber that is disposed along the solid scintillator and propagates the incident scintillation light in both end directions. And at least one set of detectors connected to both ends of the fiber to detect the scintillation light, wherein the detector is composed of a plurality of avalanche photodiodes.

  According to the present invention, since the detector is constituted by a plurality of avalanche photodiodes, the entire apparatus can be reduced in size and weight.

It is the schematic which shows the structure of the radiation detection apparatus which concerns on embodiment, FIG. 1A is a top view, FIG. 1B is a cross-sectional view. It is a schematic explanatory drawing of the several avalanche photodiode in a detector. It is a schematic block diagram of a detector. It is a block diagram of a signal processing part. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is a top view similar to FIG. 1A which shows the modification of a wavelength conversion fiber. It is sectional drawing similar to FIG. 1B which shows the modification of a light reflection layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The radiation detection apparatus of the present invention is a radiation management system for monitoring radioactive contamination with a radiation monitor in a nuclear facility such as a nuclear power plant or a medical facility, a reactor operation monitoring monitor such as a process radiation monitor, and a work management. It can be applied in a wide variety of areas such as area monitor, dust monitor, landry monitor, gate monitor for entering / exiting the management area, article carry-out monitor, body surface gate radiation monitor, process radiation monitor. It can also be applied to survey meters, detectors for non-destructive inspection, hall body counters, etc. outside nuclear facilities.

  1A and 1B are schematic diagrams illustrating a configuration of a radiation detection apparatus according to an embodiment, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view. As illustrated in FIG. 1A, the radiation detection apparatus 10 includes a solid scintillator 11, a wavelength conversion fiber (fiber) 12, a detector 13, and a signal processing unit 15.

  The solid scintillator 11 is provided in a flat plate shape formed in a rectangular shape in plan view, and the plane size is set to, for example, A4 size. The solid scintillator 11 is made of a plastic scintillator that emits scintillation light when excited by incident radiation. As shown in FIG. 1B, the solid scintillator 11 is sandwiched by layer structures from the upper and lower sides of the figure, and includes a light shielding layer 17 located on the upper side in the figure and a light reflecting layer 18 located on the lower side in the figure. Located between and. An air layer 19 is provided between the solid scintillator 11 and the light reflecting layer 18.

  The light shielding layer 17 is made of, for example, an aluminum vapor deposition film or a titanium oxide film, and is integrally fixed on a plane serving as a surface of the solid scintillator 11 (upper surface in FIG. 1B). The light shielding layer 17 has a function of not transmitting light from the outside and transmitting only radiation from the outside to the inside (solid scintillator 11 side). The light shielding layer 17 also has a function of reflecting the scintillation light incident from the solid scintillator 11.

  The surface side of the light shielding layer 17 is a side on which radiation is incident from an external radioactive substance. Therefore, a contamination prevention film (not shown) may be formed on the surface side of the light shielding layer 17 to protect it from contamination. Such a contamination prevention film can be, for example, a 6 μm thick PED (polyethylene terephthalate) film.

  The light reflection layer 18 is made of, for example, an aluminum vapor deposition film or a titanium oxide film deposited on the surface. The light reflecting layer 18 has a function of not transmitting light from the outside and a function of reflecting scintillation light emitted from the solid scintillator 11.

  Although not shown, a shield is provided on the outer peripheral side of the solid scintillator 11 to prevent the scintillation light from being emitted to the outside, and the light and radiation from the outside are solid solid scintillators from portions other than the light shielding layer 17. 11 is also prevented from entering. Moreover, the radiation detection apparatus 10 is formed in a panel shape by each structure shown to FIG. 1B.

  The wavelength conversion fiber 12 has a function of receiving scintillation light emitted from the solid scintillator 11 and propagating the scintillation light in both end directions. A plurality of wavelength conversion fibers 12 (four in the present embodiment) are provided, and each extend in a linear direction parallel to the short side of the solid scintillator 11. Accordingly, the plurality of wavelength conversion fibers 12 are arranged in a “sparse” manner in the same direction and spaced from each other. The upper end in FIG. 1A serving as one end of the wavelength conversion fiber 12 is disposed in the vicinity of one end edge serving as one long side of the solid scintillator 11. On the other hand, the lower end in FIG. 1A serving as the other end of the wavelength conversion fiber 12 is disposed in the vicinity of the end edge serving as the other long side facing the one long side of the solid scintillator 11. The wavelength conversion fiber 12 may be a bundle fiber in which a plurality of the wavelength conversion fibers 12 are bundled.

  In the above configuration, the wavelength conversion fiber 12 is disposed in the air layer 19 along the inner surface (the lower surface in FIG. 1B) of the solid scintillator 11. The wavelength conversion fiber 12 is formed by processing a resin containing a phosphor also called a wavelength shifter. The phosphor is selected so that the emission wavelength band of the scintillation light of the solid scintillator 11 and the absorption wavelength band of the phosphor itself overlap. The fluorescence (scintillation light) that has reached the wavelength conversion fiber 12 and has undergone fluorescence conversion is transmitted through the wavelength conversion fiber 12 in both directions.

  When radiation is incident from the outside through the light shielding layer 17, the solid scintillator 11 generates scintillation light. The light reflection layer 18 reflects the generated scintillation light and propagates it to the wavelength conversion fiber 12 through the air layer 19. The light shielding layer 17 reflects the scintillation light incident from the solid scintillator 11 and propagates it again to the wavelength conversion fiber 12 through the solid scintillator 11. Therefore, no matter where the scintillation light is generated in the solid scintillator 11, it is reflected by the light shielding layer 17, or reaches the wavelength conversion fiber 12 through the light reflection layer 18 and the air layer 19. Thereby, the amount of condensing can be increased.

  The scintillation light incident on the wavelength conversion fiber 12 propagates toward both ends, is emitted from the end faces, and is photoelectrically converted by the detector 13 and detected.

  The detector 13 includes a plurality of avalanche photodiodes (hereinafter, may be referred to as “APD”), and detects scintillation light as a pair connected to both ends of the same wavelength conversion fiber 12. To do. FIG. 2 is a schematic explanatory diagram of a plurality of avalanche photodiodes in the detector. As shown in FIG. 2, the detector 13 can use a photon counting device in which a plurality of APDs 13a are arranged in two orthogonal directions to form a multi-pixel. When the APD 13a is operated with the reverse voltage set to be equal to or higher than the breakdown voltage, a saturation output unique to the element is generated by light incidence regardless of the amount of light. The state in which the APD 13a is operated with this voltage is the Geiger mode, and the APD 13a in the present embodiment is an APD called Si-PM (Silicon Photomultiplier) that operates in the Geiger mode. In the Geiger mode, even when one photon is detected, a large output can be obtained due to a discharge phenomenon, and thus, weak light at a photon counting level can be detected. The electric pulse signal (electric signal) output from the APD 13a is input to the signal processing unit 15 (see FIG. 1).

  The plurality of pixelated APDs 13a each output the same pulse when detecting photons, and the pulses generated by the plurality of APDs 13a are output as superimposed signals. Therefore, in FIG. 2, for example, when photons are simultaneously incident and detected on each of the three APDs 13a that are blackened, a signal having a height in which three pulses are superimposed is output. The number of output pulses from each APD 13a is one, and it does not change depending on the number of incident photons. Only one output pulse is generated when one photon enters one APD 13a or when two photons enter at the same time. It becomes.

  As described above, since the detector 13 can detect the scintillation light by the plurality of APDs 13a, the detector 13 can be reduced in size and weight as compared with the case where a conventional photomultiplier tube is used. Therefore, the detector 13 can be arranged in the vicinity of the edge of the solid scintillator 11 and integrated with the structure including the panel-shaped solid scintillator 11 and the like. Thereby, the whole apparatus of the radiation detection apparatus 10 which united the solid scintillator 11 and the detector 13 can be reduced in size and weight. As a result, the radiation detection apparatus 10 can be installed in a narrow place, and a support post for installation in a high place can be made in a simple structure, and the degree of freedom in the installation place and usage mode can be improved.

  FIG. 3 is a schematic configuration diagram of the detector. The detector 13 includes a control unit 13b and a temperature sensor 13c in addition to the plurality of APDs 13a. The control unit 13b includes a processor and a storage medium that execute various processes necessary for detecting scintillation light. The temperature sensor 13c is provided in the vicinity of the APD 13a, for example, on the same circuit board on which the APD 13a is mounted.

  The control means 13b includes a reverse voltage application unit 13ba and a temperature adjustment unit 13bb. The control means 13b receives the signals output from the plurality of APDs 13a and outputs them to the signal processing unit 15 (see FIG. 1). The control unit 13b includes a reverse voltage application unit 13ba that applies a reverse voltage to the APD 13a, and adjusts the reverse voltage applied to the APD 13a according to the temperature data output from the temperature sensor 13c. This makes it possible to stabilize the output voltage level of the APD 13a whose amplification degree varies according to the ambient temperature. Moreover, the control means 13b is provided with the temperature adjustment part 13bb which controls to cool APD13a. The temperature adjustment unit 13bb includes a thermistor and a Peltier element. The thermistor measures the ambient temperature of the APD 13a and compares it with a preset temperature. Adjust to temperature. This makes it possible to reduce the noise of the APD 13a whose noise level varies according to the ambient temperature.

  FIG. 4 is a block diagram of the signal processing unit. As shown in FIG. 4, the signal processing unit 15 includes an I / V conversion circuit 15a, a signal amplification circuit 15b, a discrete circuit 15c, a simultaneity detection circuit 15d, a counting circuit 15e, an A / D conversion circuit 15f, and a CPU 15g. ing. In FIG. 4, reference numeral 13A is attached to the detector 13 connected to one end of the same wavelength conversion fiber 12 (see FIG. 1), and reference numeral 13B is attached to the detector connected to the other end. The signal processing unit 15 is electrically connected to the pair of detectors 13A and 13B and processes the electrical signals of the detectors 13A and 13B. One I / V conversion circuit 15a, signal amplification circuit 15b, discrete circuit 15c, and A / D conversion circuit 15f are provided for each of the detectors 13A and 13B. One simultaneity detection circuit 15d and one counting circuit 15e are provided for each of the wavelength conversion fibers 12. The signal processing unit 15 has the above configuration added according to the number of wavelength conversion fibers 12 installed, and a part of the configuration is not shown in FIG.

  The electric pulse signals output from the detectors 13A and 13B are first input to the I / V conversion circuit 15a in the signal processing unit 15. Since the electric pulse signal output from the APD 13a (see FIG. 2) of the detectors 13A and 13B is a current signal, it is converted into a voltage signal by the I / V conversion circuit 15a. After that, the converted voltage signal is amplified by the signal amplifier circuit 15b, and then pulse detection is performed when the discriminator circuit 15c exceeds a predetermined discriminant level. The outputs of the two discrete circuits 15c are input to one simultaneity detection circuit 15d. The simultaneity detection circuit 15d is a signal in which the electrical pulse signals detected by the two discrete circuits 15c are simultaneously generated by a pair of detectors 13A and 13B connected to the same wavelength conversion fiber 12 (see FIG. 1). Whether or not is detected.

  When the simultaneity can be detected in the simultaneity detection circuit 15d, it is determined that the electric pulse signal is generated when the scintillation light reaches the detectors 13A and 13B. On the other hand, when simultaneity cannot be detected, it is determined as an electric pulse signal due to the inherent noise of the APD 13a. The output of the simultaneity detection circuit 15d is input to the counting circuit 15e and the CPU 15g. The counting circuit 15e performs the counting process only when the simultaneity is detected by the simultaneity detecting circuit 15d. As a result, the inherent noise of the APD 13a is excluded, and counting with less background noise becomes possible.

  Further, the CPU 15g starts A / D conversion by the A / D conversion circuit 15f only when the simultaneity is detected by the simultaneity detection circuit 15d, and calculates the peak value of the electric pulse signal output from the discrete circuit 15c. Capture and perform wave height analysis. Thereby, it becomes possible to perform energy characteristic evaluation with little background noise. Since the crest value increases as the number of photons of the scintillation light incident on the APD 13a increases as described above, the radiation dose is calculated from the result of the crest analysis processing by the CPU 15g and the result of the counting processing. Can do.

  In the present embodiment, there are four wavelength conversion fibers 12 (see FIG. 1), and a pair of detectors 13A and 13B are connected to both ends. Therefore, in the signal processing unit 15, the CPU 15g can determine which of the four wavelength conversion fibers 12 has performed the detection. Therefore, the position where the radiation is incident on the solid scintillator 11 can be specified as the resolution obtained by roughly dividing the solid scintillator 11 into four, and the position of the radiation source can be specified.

  As described above, according to the present embodiment, the detector 13 is configured by the plurality of APDs 13a. Therefore, not only the detector 13 but also the structure around the solid scintillator 11 incorporating the detector 13 in the vicinity of the edge is large. Increase in weight and weight can be suppressed. Further, since the signal processing unit 15 performs signal processing using the synchronism of the generation timing of the electrical pulse signals output from the pair of detectors 13A and 13B, the influence of noise is reduced and the detection capability is increased. be able to.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications. Moreover, there is no restriction | limiting in particular about the numerical value, dimension, material, and direction which were demonstrated by the said embodiment. Other modifications may be made as appropriate without departing from the scope of the object of the present invention.

  For example, the wavelength conversion fiber 12 in FIG. 1A can be replaced with the configuration shown in FIGS. 5 to 11 are plan views similar to FIG. 1A showing modifications of the wavelength conversion fiber. In the modification of FIG. 5, the wavelength conversion fiber 31 is bent in a U shape, and both ends thereof are disposed in the vicinity of one end edge (the lower end edge in FIG. 5) that is one long side of the solid scintillator 11. Therefore, the detector 13 can also be arranged in the vicinity of one end edge of the solid scintillator 11, and the number of detectors 13 can be reduced as compared with the above embodiment.

  The wavelength conversion fiber 31 includes a semicircular arc portion 31a and a plurality of (two in this modification) including a pair of linear portions 31b extending in parallel to both ends of the semicircular arc portion 31a. . The semicircular arc portion 31 a is formed outside the end portion of the solid scintillator 11. The pair of linear portions 31b are linearly formed in the region facing the solid scintillator 11 (the region indicated by the broken line in the figure), as in the above embodiment. A total of four linear portions 31b in the two wavelength conversion fibers 31 are arranged in parallel at approximately equal intervals, as in the above embodiment. In this modification, one of the two wavelength conversion fibers 31 is disposed on the right side in FIG. 5 and the other is disposed on the left side in FIG. 5. It is possible to specify the position where the light is incident. With such a configuration, the number of the wavelength conversion fibers 31 can be reduced and the product cost can be reduced while keeping the same region where the scintillation light is incident on the wavelength conversion fiber 31 compared to the above embodiment. .

  As in the modification of FIG. 5, two wavelength conversion fibers 32 of the modification of FIG. 6 are provided with a semicircular arc portion 32a and a pair of linear portions 32b. However, the semicircular arc portion 32a in FIG. 6 is larger in diameter than the semicircular arc portion 31a in FIG. 5, and the two wavelength conversion fibers 32 are arranged so as to intersect at the semicircular arc portion 32a. Thus, one of the linear portions 32b of the other wavelength conversion fiber 32 is disposed between the pair of linear portions 32b of the one wavelength conversion fiber 32, and vice versa. By increasing the diameter of the semicircular arc portion in this way, it is possible to reduce the loss of scintillation light propagating through the wavelength conversion fiber 32.

  The wavelength conversion fiber 33 of the modified example of FIG. 7 includes a semicircular arc-shaped portion 33a and a linear portion 33b, as in the modified examples of FIGS. However, the plurality of semicircular arc-shaped portions 33a and the plurality of linear portions 33b are alternately arranged in the extending direction on the same wavelength conversion fiber 33, so that the whole is formed in a zigzag shape. In this manner, the number of wavelength conversion fibers 33 and detectors 13 installed can be reduced by forming a zigzag shape.

  In the modification of FIG. 8, two wavelength conversion fibers 33 and 34 are provided, and one of them has the same shape as the wavelength conversion fiber 33 (hereinafter referred to as the first wavelength conversion fiber 33) of the modification of FIG. It is bent and formed. The other wavelength conversion fiber 34 (hereinafter referred to as the second wavelength conversion fiber 34) is also bent and formed in a zigzag shape as a whole, but the direction is different from that of the first wavelength conversion fiber 33. Specifically, in the second wavelength conversion fiber 34, a plurality (two in this modification) of semicircular arcs 34a and a plurality (three in this modification) of linear parts 34b alternate in the extending direction. The linear portion 34 b extends in a direction intersecting (orthogonal) with the linear portion 33 b of the first wavelength conversion fiber 33. Therefore, in this modification, the linear portions 33b and 34b of the wavelength conversion fibers 33 and 34 are formed in a lattice shape.

  The wavelength conversion fiber 50 of the modification of FIG. 9 includes semicircular arc portions 33a and 34a and linear portions 33b and 34b similar to those of the modification of FIG. 8, and further has two wavelengths in the modification of FIG. A connecting portion 50a is provided to connect the conversion fibers 33 and 34 into one. The connecting portion 50a is formed in a bent shape so as to connect the lower end of the rightmost linear portion 33b in FIG. 9 and the right end of the lowermost linear portion 34b. Therefore, in the present modification, the single wavelength conversion fiber 50 has the two zigzag folded portions 50A that are zigzag folded as described above, and the linear portions 33b and 34b are formed in a lattice shape.

  The wavelength conversion fiber 51 of the modified example of FIG. 10 has four linear portions 51b that are the same as the modified example of FIG. 6 and the semicircular arc-shaped portion 32a of FIG. 6 above the solid scintillator 11 in FIG. Two connecting portions 51a connected to the linear portion 51b are provided. The wavelength conversion fiber 51 further includes a semicircular arc-shaped portion 51c that is continuous with the lower ends of the two linear portions 51b inside the four linear portions 51b. Therefore, in the present modification, the four linear portions 51b are arranged in parallel at approximately equal intervals by bending the single wavelength conversion fiber 51 so as to spiral once.

  The wavelength conversion fiber 52 of the modified example of FIG. 11 includes six linear portions 52b, three first coupling portions 52a provided above the solid scintillator 11 in FIG. 11, and two pieces provided below. And a second connecting portion 52c. The 1st connection part 52a is continued to the linear part 52b which adjoins 3 in the left-right direction of FIG. The second connecting portion 52c is connected to two adjacent linear portions 52b except for the leftmost and rightward linear portions 52b in the left-right direction. Therefore, in the present modification, the six linear portions 52b are arranged in parallel at approximately equal intervals by bending the single wavelength conversion fiber 52 so as to spiral twice. In the bending of the wavelength conversion fiber 52, the number of spirals as described above may be three or more.

  Moreover, the light reflection layer 18 can be replaced with the configuration shown in FIGS. 12A to 12C. 12A to 12C are cross-sectional views similar to FIG. 1B showing a modification of the light reflecting layer. The light reflecting layer 35 of the modified example of FIG. 12A includes a plurality of inclined surfaces that alternately form peaks and valleys on the inner surface side, and is formed so that one wavelength conversion fiber 12 is received in each valley. Yes. The light reflecting layer 36 of the modification of FIG. 12B is formed so that a plurality of concave portions formed in an arc shape in a cross-sectional view are arranged, and the wavelength conversion fibers 12 are received one by one in the concave portions. By forming the light reflecting layers 35 and 36 in such a shape, the scintillation light reaching the wavelength conversion fiber 12 can be increased.

  In the modification of FIG. 12C, the light guide 40 that holds the wavelength conversion fiber 12 is disposed in the air layer 19. The light guide 40 is made of a resin material having a high light transmittance, such as PMMA (polymethyl methacrylate resin), and has a concave receiving portion 40 a for receiving the wavelength conversion fiber 12. By receiving the wavelength conversion fiber 12 in the receiving portion 40a, the wavelength conversion fiber 12 can be positioned in contact with or approaching the solid scintillator 11, and the wavelength conversion fiber 12 is positioned in the left-right direction in the drawing. Can do. Thereby, the optical characteristic of the wavelength conversion fiber 12 can be exhibited satisfactorily, and the assemblability of the radiation detection apparatus 10 can be improved.

  Further, in the detector 13, a plurality of APDs 13a may be arranged in one direction as long as scintillation light can be detected as in the above embodiment.

  In addition, as the planar shape of the solid scintillator 11 or a panel-like structure including the solid scintillator 11, an arbitrary shape surrounded by straight lines and curves such as a circle, an ellipse, and a polygon may be adopted. In this case, the edge facing the one edge of the solid scintillator 11 can be set as an edge located on the opposite side with respect to the center position or the center of gravity of the planar shape of the solid scintillator 11.

  Moreover, the installation position of the detector 13 may be a place away from the solid scintillator 11 by extending the wavelength conversion fiber 12, a case separate from the solid scintillator 11, or the like.

  In the above embodiment, the wavelength conversion fiber 12 is used. However, an optical fiber that does not perform wavelength conversion may be used.

DESCRIPTION OF SYMBOLS 10 Radiation detector 11 Solid scintillator 12 Wavelength conversion fiber (fiber)
13 Detector 13a APD (avalanche photodiode)
13ba Reverse voltage application unit 13bb Temperature adjustment unit 15 Signal processing unit 31 Wavelength conversion fiber (fiber)
31a Semicircular arc portion 31b Linear portion 32 Wavelength conversion fiber (fiber)
32a Semicircular arc part 32b Linear part 33 Wavelength conversion fiber (fiber)
33a Semicircular arc part 33b Linear part 40 Light guide

Claims (16)

A solid scintillator that emits scintillation light when excited by incident radiation;
At least one fiber disposed along the solid scintillator and propagating the incident scintillation light in both end directions;
And at least one set of detectors connected to both ends of the fiber to detect the scintillation light,
The detector includes a plurality of avalanche photodiodes.   The radiation detector according to claim 1, wherein the detector has the plurality of avalanche photodiodes operating in Geiger mode arranged in one direction or two directions orthogonal to each other.   The radiation detector according to claim 1, wherein the detector is arranged in the vicinity of an edge of the solid scintillator.   The radiation detection apparatus according to claim 1, wherein the fiber is bent and both ends thereof are arranged in the vicinity of one end edge of the solid scintillator.   The fiber is provided with a plurality of semicircular arc-shaped portions and a pair of linear portions extending in parallel to both ends of the semicircular arc-shaped portion, and the other fibers between the pair of linear portions. The radiation detection apparatus according to claim 4, wherein any one of the linear portions is disposed.   The radiation detection apparatus according to claim 4, wherein the fiber is formed in a zigzag shape in which semicircular arc portions and linear portions are alternately arranged in the extending direction.   A plurality of the fibers extend in a linear direction, and one end of each fiber is disposed in the vicinity of one end edge of the solid scintillator, and the other end of each fiber is in the vicinity of an end facing the one end edge of the solid scintillator. The radiation detection apparatus according to claim 1, wherein the radiation detection apparatus is arranged. Two fibers are provided, and each of the semicircular arc portions and the linear portions are alternately arranged in the extending direction and bent into a zigzag shape,
The radiation detection apparatus according to claim 1, wherein the linear portion of one of the fibers and the linear portion of the other of the fibers are formed in a lattice shape. The fiber is a single fiber, and has two zigzag folds formed by bending a semicircular arc shape portion and a linear shape portion alternately in the extending direction to bend in a zigzag shape,
The radiation detection according to any one of claims 1 to 3, wherein the linear part of one of the zigzag folding parts and the linear part of the other zigzag folding part are formed in a lattice shape. apparatus.   The radiation detection apparatus according to claim 1, wherein the fiber is bent and formed in a spiral shape having a plurality of linear portions extending in parallel at predetermined intervals.   The radiation detection apparatus according to claim 1, wherein the fiber is positioned by a light guide having a light guide property. A signal processing unit that is electrically connected to the detectors provided at both ends of the fiber and processes electrical signals of the detectors;
The radiation according to any one of claims 1 to 11, wherein the signal processing unit performs signal processing using the synchronism of generation timings of electrical signals output from the plurality of detectors. Detection device.   The radiation detection according to claim 12, wherein the signal processing unit performs a counting process only when electrical signals output from the detectors provided at both ends of the same fiber are generated simultaneously. apparatus.   13. The signal processing unit performs a pulse height analysis process on the electrical signal only when electrical signals output from the detectors provided at both ends of the same fiber are simultaneously generated. Or the radiation detection apparatus of Claim 13.   The radiation detector according to claim 1, wherein the detector includes a reverse voltage application unit for applying a reverse voltage according to an ambient temperature.   The radiation detector according to any one of claims 1 to 15, wherein the detector includes a temperature adjusting unit for adjusting an ambient temperature.

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