JP2004233240A - Radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detector capable of preventing output decline wherever gamma rays enter, performing accurate position discrimination, and maintaining high resolution and high image quality. <P>SOLUTION: In this radiation detector wherein a scintillator group 10, a light guide 20 and photomultipliers 30, 40 are optically coupled, the light guide 20 is subdivided by adjusting the depth of the void 22 formed therein and a reflecting member 21 so that a detection distribution in an adjacent photomultiplier is properly distributed so as to be changed at a fixed rate corresponding to the change of the incident position of light. As for the light transmitted from the scintillator group 10 to the photomultipliers 30, 40, a loss caused by reflection/transmission phenomenon when passing through the light guide 20 is suppressed to the minimum, to thereby prevent the output decline. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention detects radiation (gamma rays) emitted from a radioisotope (RI) administered to a subject and accumulated at a site of interest, and obtains a tomographic image of an RI distribution of the site of interest, for example, The present invention relates to a radiation detector used for a positron CT device, a single photon ECT device, and the like.
[0002]
[Prior art]
This type of radiation detector is composed of a scintillator that emits gamma rays emitted from a subject and emits light, and a photomultiplier tube that converts the light emitted from the scintillator into a pulsed electric signal. Conventionally, in such a radiation detector, a scintillator and a photomultiplier tube correspond to each other on a one-to-one basis. In recent years, however, a smaller number of photoelectrons have been added to a bundle of a plurality of scintillator crystals in an array. By employing a method in which the multipliers are connected and the incident position of the gamma ray is determined from the output ratio of each of the photomultiplier tubes, a high positional resolution is realized while reducing the number of components.
[0003]
In such a recent technique, among the plurality of scintillator crystals forming the array, only the scintillator crystal on which gamma rays are incident emits light, and the scintillator light emitted at this specific position is converted into a plurality of photomultiplier tubes. The incident position is determined from the output ratio of. Accurate discrimination of the position leads to improvement of an image of a medical diagnostic apparatus or the like in which the detector is adopted. In the method of determining the gamma ray incident position from the output ratio of the photomultiplier tube, the amount of light incident on one photomultiplier tube changes according to the scintillator position on which the gamma ray has entered. How to properly distribute the scintillator light to each photomultiplier tube is important for discrimination accuracy of the incident position. Various methods have been proposed for that purpose. When roughly classified, the distribution is adjusted by changing the area of the reflective film at the joint surface between a plurality of scintillators (for example, Patent Document 1).
FIG. 6, Patent Document 2
FIG. 5), a light guide made of a transparent resin or the like is interposed between the scintillator and the photomultiplier tube, and a reflection film is embedded in the light guide to be divided into small sections, and distribution is adjusted by the area of the reflection film. What you do (for example,
Patent Document 3
[Fig. 5B]).
[0004]
[Patent Document 1]
JP-A-5-281362
[Patent Document 2]
JP-A-3-185385
[Patent Document 3]
Japanese Patent Publication No. Sho 62-500957
[0005]
Either method is effective, but the former has a manufacturing defect that it is necessary to configure a plurality of scintillator crystals while maintaining a highly controlled interval, and the position and position of a hard crystal alone It is technically very difficult to form a groove having a highly controlled depth with a desired width and depth. In addition, the latter uses a light guide, so that the light incident on each photomultiplier can be dispersed and local sensitivity unevenness can be suppressed. Is advantageous.
[0006]
Here, a configuration of a conventional radiation detector using a light guide will be described with reference to FIG. The radiation detector shown in the figure has a scintillator group 310 divided by a number of grooves 311 in which a light reflecting material or a light shielding material is embedded, and a light reflecting material or a light shielding material optically coupled to the scintillator group 310. It is composed of a light guide 320 forming small sections having different depths by a large number of embedded light shielding walls 321, and two photomultiplier tubes 330 and 340 optically coupled to the light guide 320. . This example shows a scintillator group divided into 5 channels in the X direction and 5 channels in the Y direction, that is, 25 channels in total. One photomultiplier tube can separately detect signals from two poles by the partition plates 334, 344, and the like. As a result, the scintillator light of each of 25 channels is received by the four-electrode photoelectric surface as a result. In this radiation detector, by adjusting the length of each light shielding wall 321 in the light guide 320 so as to increase from the inside to the outside, the incidence on the photomultiplier tube is adjusted, and the incidence position of the gamma ray is adjusted. That can be distinguished.
[0007]
The light guide 320 is made of an optically transparent material. The light guide 320 is cut with a saw having a multi-blade such as a dicing saw or a wire saw to form a notch of a predetermined depth, and an appropriate light reflection A light shielding wall 321 is manufactured by inserting a material or a light shielding material.
[0008]
[Problems to be solved by the invention]
However, the conventional configuration described above has the following problem.
In recent years, with the improvement in image quality of medical diagnostic equipment, high-resolution radiation detectors using high-sensitivity scintillators have been required. The number is very large. In such a situation, in order to form the light shielding wall 321 in the light guide by the above-described conventional method, for example, when a light reflecting sheet is used as the light shielding material, the sheet is not cut in the X and Y directions. The operation of individually inserting a large number of parts requires a large number of parts and is very complicated, resulting in a high cost. Further, since the area of one channel of the scintillator element is small, a reduction in output becomes a problem, and attenuation due to multiple reflections on the light reflecting sheet cannot be ignored, and the reflection efficiency is limited no matter what light reflecting sheet material is selected. As a result, the output is reduced. Even when a reflective paint such as barium sulfide is used as the reflective material, the work of filling the intricate cuts vertically and horizontally is still difficult and complicated. If the filling is inadequate, the position cannot be accurately distinguished, and the image quality at the time of imaging deteriorates.
[0009]
[Means for Solving the Problems]
The present invention has the following configuration to solve the above problems.
[0010]
That is, a radiation detector according to the present invention includes a plurality of scintillators closely arranged two-dimensionally, a light guide optically coupled to the scintillator, and an optically coupled light guide to the light guide. And a radiation detector including a plurality of photomultiplier tubes having a smaller number of photocathode poles than the number of the scintillators, wherein the light guide is formed from a plurality of input surfaces (coupling surfaces with the scintillator). (Corresponding to claim 1).
[0011]
When a gamma ray is incident on one of a plurality of scintillators closely arranged two-dimensionally, the scintillator absorbs the gamma ray and emits light. The emitted light passes through the scintillator and enters the light guide. Light incident on the light guide is dispersed in the light guide and is incident on each photomultiplier tube. The light guide is sectioned so that the ratio of the amount of light incident on each photomultiplier tube changes in accordance with the position of the scintillator on which the gamma ray has entered.However, this section does not use a conventional reflective film, but instead uses a gap. By using the reflection / transmission phenomenon, even if multiple reflections occur in the light guide, the light can be guided to the photomultiplier without lowering the output, and accurate position discrimination can be performed.
[0012]
Alternatively, the gap for partitioning the light guide is formed from the output surface (the coupling surface with the photomultiplier) side (corresponding to claim 2).
[0013]
Since the air gap is opened only on the photomultiplier tube side, even when an adhesive or the like is used when connecting the light guide to the scintillator group and the photomultiplier tube, the bonding surface is not smooth and more bonding is performed. Since the gap is not opened on the side of the scintillator requiring the agent but is opened only on the side of the photomultiplier tube having a smooth bonding surface such as glass, it is possible to adopt a configuration in which the adhesive hardly enters the gap.
[0014]
Alternatively, the space for partitioning the light guide is formed from both sides of the input surface and the output surface (corresponding to claim 3).
[0015]
When forming the gap, the depth can be designed to be shallower than in the case where the gap is formed from one side, and the manufacturing process can be performed easily and surely without any problem.
[0016]
Further, the section of the light guide is constituted by a combination of a gap and a light shielding member formed from the input surface side or the output surface side or both sides (corresponding to claim 4).
[0017]
Alternatively, a light-shielding member is adopted only in the peripheral portion of the light guide, and the other central portion is partitioned by a gap (corresponding to claim 5).
[0018]
In places where the emission direction is prioritized over light attenuation, it may be desirable to use a light blocking member together. For example, in the peripheral portion of the light guide, since it is necessary to make the scintillator light particularly enter the photomultiplier tube immediately below, the peripheral portion is partitioned by a reflective film having a high reflectance (a transmission action is smaller than that of air). It is useful to do.
[0019]
Conversely, the attenuation of light can be further suppressed by inserting an optically-coupling material into a space at a location where light is desired to be transmitted (corresponding to claim 6).
[0020]
Alternatively, the light guide includes a sealing member for preventing foreign matter from entering a gap provided in the light guide (corresponding to claim 7).
[0021]
Further, the sealing member is composed of a sealing film made of a light transmitting material (corresponding to claim 8).
[0022]
The gap is open at the joint surface with the scintillator and the photomultiplier tube. If a foreign substance such as an adhesive used in this area flows in, it has a bad effect such as attenuating light. It is. It is particularly desirable to use a film-like material because many voids can be reliably and uniformly sealed at once.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a radiation detector according to the present invention will be described with reference to the drawings.
[0024]
(1st Embodiment)
An example according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an external perspective view of an embodiment of the radiation detector according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG.
[0025]
The radiation detector detects a gamma ray incident from above in the figure, and is roughly divided into a scintillator group 10, a light guide 20 optically coupled to the scintillator group 10, and an optically coupled to the light guide 20. And two photomultiplier tubes 30 and 40. (A single photomultiplier tube that can detect signals separately from the two poles by using the partition plates 34, 44, etc. is used.)
[0026]
The scintillator group 10 is Bi ₄ Ge ₃ 0 ₁₂ (BGO), Gd ₂ SiO ₅ (GSO), Lu _{2 (1-X)} Ce _2x (SiO ₄ ) O (LSO), NaI, BaF ₂ , CsF, and other known inorganic crystals cut out in a long columnar shape, for example, 10 in the X direction and 10 in the Y direction. Here, a light reflecting material or a light shielding member is sandwiched between the contact surfaces 11 of the respective crystals, but it is also possible to simply attach the crystals without interposing anything.
[0027]
The light guide 20 is optically coupled to the emission side of the scintillator group 10 with an adhesive or optical grease. The material of the light guide 20 is preferably an optically transparent resin material such as acrylic or epoxy, or a transparent glass.
[0028]
In this embodiment, a space 22 for defining a section of the scintillator group 10 is provided in the light guide 20 from the input surface 24 (coupling surface with the scintillator group 10). The air gap 22 is formed by cutting a predetermined depth into the light guide 20 (transparent resin) with a saw having a parallel multi-blade such as a dicing saw or a wire saw. Alternatively, it is desirable to form the lattice-like body having the shape of the void 22 by a resin molding method in which the lattice-like body is immersed.
[0029]
The length (depth) of the air gap 22 is adjusted and optimized so that the amount of light incident on one photomultiplier tube changes according to the position of the scintillator on which the gamma ray has entered. That is, the detection distribution in the adjacent photomultiplier tube is appropriately distributed so that the detection distribution changes at a fixed rate according to the change in the incident position of light.
[0030]
In the peripheral portion of the light guide, it is necessary to make the scintillator light incident on the photomultiplier tube immediately below, so that the emission direction is prioritized over the light attenuation and the reflectance is high (the transmission action is smaller than air). It is useful to partition the peripheral portion with a reflective film, and it is desirable to use the reflective member 21 as an isolating plate.
[0031]
The material of the reflection member 21 is a well-polished aluminum plate, a thin substrate coated with titanium oxide or barium sulfate, a thin substrate with a white fluororesin tape adhered thereto, a thin smooth substrate surface It is preferable that aluminum is deposited on the surface of the substrate. Particularly, SiO 2 is formed on a transparent polyester film or the like having a property of small loss at the time of reflection. ₂ And TiO ₂ (Multilayer film) in which the above multilayer film structures are laminated is optimal.
[0032]
The light guide 20 is coated with an adhesive, optical grease, or the like on a surface on the side of the input surface 24 (coupling surface with the scintillator group 10), and is optically coupled to the scintillator group 10. Since an opening is formed at the joint surface with the scintillator group 10, if a foreign substance such as an adhesive flows into this gap, it has an adverse effect such as attenuating light. Therefore, it is useful to adopt a configuration including the sealing member 23. The sealing member 23 is formed of a thin sealing film made of a light-transmitting material, and can reliably and uniformly seal many voids at once.
[0033]
Now, as shown in FIG. 2, for example, scintillators 10 arranged in the X direction _i1 -10 _i10 Gamma rays incident on (i = 1 to an integer from 1 to 10) are converted into visible light. Next, the light is guided to the photomultiplier tube 30 through the light guide 20 which is optically coupled. At this time, the photocathode 31 arranged in the X direction is used. ₁ (41 ₁ ) And photocathode 31 ₂ (41 ₂ The length (depth) of each of the gaps 22 and the reflection member 21 as the separating plate of the light guide 20 is adjusted so that the output ratio of the light guide 20 changes at a constant rate. More specifically, the photocathode 31 ₁ Output from P ₁ , Photocathode 31 ₂ Output from P ₂ Then, the calculated value (P ₁ −P ₂ ) / (P ₁ + P ₂ ) Is the scintillator 10 _i1 -10 _i10 Is adjusted so as to change at a constant rate according to the position of the.
[0034]
On the other hand, scintillators 10 arranged in the Y direction _1j -10 _10j Similarly, in the case of (j = 1 to an integer from 1 to 10), light is guided to the photomultiplier tube 30 through the optically coupled light guide 20, but the photocathode arranged in the Y direction 31 ₁ (31 ₂ ) And the photocathode 41 ₁ (41 ₂ The length (depth) of each of the gaps 22 and the reflection member 21 as the separating plate of the light guide 20 is adjusted so that the output ratio of the light guide 20 changes at a constant rate. More specifically, the photocathode 31 ₁ Output from P ₁ , Photocathode 41 ₁ Output from P ₃ Then, the calculated value (P ₁ −P ₃ ) / (P ₁ + P ₃ ) Is the scintillator 10 _1j -10 _10j Is adjusted so as to change at a constant rate according to the position of the.
[0035]
The outer surfaces of the scintillators not facing each other are covered with a reflective material (not shown) except for an optical coupling surface with the light guide 20.
[0036]
FIG. 3 shows the photocathode 31 of the photomultiplier tubes 30 and 40. ₁ , 31 ₂ And 41 ₁ , 41 ₂ FIG. 4 is a block diagram showing a schematic configuration of a position detection unit that detects a gamma ray incident position based on an output from the device. As shown in the figure, in order to detect the incident position of the gamma ray in the X direction, the photocathode 31 ₁ Output P from ₁ And the photocathode 41 ₁ Output P from ₃ Are input to the adder 1 and the photoelectric surface 31 ₂ Output P from ₂ And the photocathode 41 ₂ Output P from ₄ Are input to the adder 2. Each addition output P of both adders 1 and 2 ₁ + P ₃ And P ₂ + P ₄ Is input to the position discriminating circuit 5, and the incidence position of the gamma ray in the X direction is obtained based on both the added outputs. Similarly, in order to detect the incident position of the gamma ray in the Y direction, the photoelectric surface 31 ₁ Output P from ₁ And photoelectric surface 31 ₂ Output P from ₂ Is input to the adder 3 and the photoelectric surface 41 ₁ Output P from ₃ And the photocathode 41 ₂ Output P from ₄ Are input to the adder 4. Each addition output P of both adders 3 and 4 ₁ + P ₂ And P ₃ + P ₄ Is input to the position discriminating circuit 6, and the incident position of the gamma ray in the Y direction is obtained based on both the added outputs.
[0037]
The operation of the radiation detector configured as described above will be described. When a gamma ray enters one of a plurality of scintillator groups 10 closely arranged two-dimensionally, the scintillator absorbs the gamma ray and emits light. The emitted light passes through the scintillator and enters a light guide 20 which is divided into small sections having different depths by a gap 22 or the like. Light incident on the light guide 20 is dispersed in the light guide 20 and is incident on each of the photomultiplier tubes 30 and 40. Since the detector according to the present invention has the above-described configuration, the light emitted by the gamma ray incident on the scintillator emits light at the interface between the medium portion of the light guide 20 and the gap 22 (the air separating plate) and the light guide 20. Light is transmitted to the photomultiplier tubes 30 and 40 by a reflection / transmission phenomenon caused by a difference in refractive index at the interface between the medium portion and the reflection member 21. At this time, since the loss due to the reflection and transmission phenomena is minimized, the light can be guided to the photomultiplier tubes 30 and 40 without lowering the output even if multiple reflections occur in the light guide 20, so that the light can be accurately reflected. Since the position can be discriminated, the overall image quality can be improved.
[0038]
(2nd Embodiment)
Next, an example according to the second embodiment of the present invention will be described with reference to FIG. FIG. 4 is an external perspective view of one embodiment of the radiation detector according to the present invention.
[0039]
The radiation detector according to the second embodiment is divided by a contact surface 11 between crystals in which a light reflecting material or a light shielding member is interposed, and has 10 scintillators in the X direction and 10 scintillators in the Y direction, for a total of 100 scintillators. , A light guide 120 optically coupled to the scintillator group 10, and two photomultiplier tubes 30 and 40 optically coupled to the light guide 120. It is composed of In this embodiment, one photomultiplier tube is used which can detect signals separately from the two poles by the partition plates 34, 44 and the like.
[0040]
In this embodiment, in the light guide 120, a plurality of gaps 122 as a separating plate and a reflecting member are provided so as to define the section of the scintillator group 10 from the output surface 125 (the coupling surface with the photomultiplier tubes 30 and 40). The depth of each of the air gaps 122 and the reflecting members 121 is adjusted so that the amount of light incident on one photomultiplier tube changes according to the position of the scintillator on which the gamma ray has entered.
[0041]
Before the light guide 120 is optically coupled to the photomultiplier tubes 30 and 40 on the output surface 125 (coupling surface with the photomultiplier tubes 30 and 40) side of the light guide 120, A light-transmitting thin sealing film 126 is interposed so that an adhesive or optical grease or the like does not enter the gap 122.
[0042]
When a gamma ray enters one of a plurality of scintillator groups 10 closely arranged two-dimensionally, the scintillator absorbs the gamma ray and emits light. The emitted light passes through the scintillator and enters the light guide 120. Light incident on the light guide 120 is dispersed in the light guide 120 and is incident on each of the photomultiplier tubes 30 and 40. Small sections having different depths are formed in the light guide 120, and light emitted when gamma rays enter the scintillator emits light at the interface between the medium portion of the light guide 120 and the gap 122 (air) serving as a separator. Light is transmitted to the photomultiplier tubes 30 and 40 by a reflection / transmission phenomenon caused by a difference in refractive index at the interface between the medium portion of the light guide 120 and the reflection member 121 made of a multilayer film or the like. At this time, since the loss due to the reflection and transmission phenomena is minimized, even if multiple reflections occur in the light guide 120, the light can be guided to the photomultiplier tubes 30 and 40 without lowering the output. Since the position can be discriminated, the overall image quality can be improved.
[0043]
As described above, also in the second embodiment, the same material as in the first embodiment can be used, and the same effect can be obtained. However, the first embodiment in which the air gap opens on the input surface side of the light guide is used. The second embodiment, which opens on the output surface side, is more advantageous than the embodiment in the following point. That is, the input surface side of the light guide is in contact with the end of the scintillator group, and thus is not a completely smooth surface.On the other hand, the output surface side is in contact with the glass surface serving as the input surface of the photomultiplier tube. The output surface side of the light guide can be simply crimped without adhesive, or can be optically bonded with a very small amount of adhesive, and a sealing film to prevent the adhesive from entering the gap is provided. Can be omitted.
[0044]
(Third embodiment)
Next, an example according to a third embodiment of the present invention will be described with reference to FIG. FIG. 5 is an external perspective view of one embodiment of the radiation detector according to the present invention.
[0045]
The radiation detector according to the third embodiment is divided by a contact surface 11 between crystals in which a light reflecting material or a light shielding member is interposed, and 10 scintillators in the X direction and 10 scintillators in the Y direction, totaling 100 scintillators. , A light guide 220 optically coupled to the scintillator group 10, and two photomultiplier tubes 30, 40 optically coupled to the light guide 220. It is composed of In this embodiment, one photomultiplier tube is used which can detect signals separately from the two poles by the partition plates 34, 44 and the like.
[0046]
In this embodiment, the light guide 220 has a section of the scintillator group 10 from both the input surface 224 (the surface where the scintillator group 10 is coupled) and the output surface 225 (the surface where the photomultiplier tubes 30 and 40 are coupled). Are provided with a plurality of gaps 222 as a separating plate and a reflecting member 221. The depth of the reflection member 222 and the reflection member 221 is adjusted.
[0047]
In this embodiment, the scintillator group 10 is provided on the input surface 224 (coupling surface with the scintillator group 10) side and the output surface 225 (coupling surface with the photomultiplier tubes 30 and 40) side of the light guide 220. Before being optically coupled to the photomultiplier tubes 30 and 40, light-transmitting thin films 223 and 226 for sealing the gap 222 of the light guide 220 so as not to be filled with an adhesive or optical grease are sandwiched therebetween. Structure.
[0048]
When a gamma ray enters one of a plurality of scintillator groups 10 closely arranged two-dimensionally, the scintillator absorbs the gamma ray and emits light. The emitted light passes through the scintillator and is incident on a light guide 220 having small sections having different depths formed by a plurality of gaps or the like as a separating plate. Light incident on the light guide 220 is dispersed in the light guide 220 and is incident on each of the photomultiplier tubes 30 and 40. Here, since the present detector has the above-described configuration, the light emitted when the gamma ray enters the scintillator emits light at the interface between the medium portion of the light guide 220 and the gap 222 serving as a separating plate and the light guide 220. Light is transmitted to the photomultiplier tubes 30 and 40 by a reflection / transmission phenomenon caused by a difference in refractive index at an interface between the medium portion and the reflection member 221 formed of a multilayer film. At this time, since the loss due to the reflection and transmission phenomena is minimized, even if multiple reflections occur in the light guide 220, the light can be guided to the photomultiplier tubes 30 and 40 without lowering the output. Since the position can be discriminated, the overall image quality can be improved.
[0049]
This embodiment is also made of the same materials as those of the first and second embodiments, and can achieve the same effects, but is advantageous in the following points. That is, it is difficult to precisely process a thin and deep groove like the gap, and in the present embodiment in which the groove can be processed separately from the input surface side and the output surface side, the groove depth can be reduced to half. It can be easily processed.
[0050]
In each of the above-described embodiments, a radiation detector configured by optically coupling 100 scintillators, light guides, and 4 photomultiplier tubes has been described as an example. However, the present invention is not limited to this. It is needless to say that the number of scintillators and photomultiplier tubes can be arbitrarily set without limitation.
[0051]
【The invention's effect】
As is apparent from the above description, according to the present invention, since the small section of the light guide is constituted by the gap, the attenuation of light traveling in the light guide is minimized and guided to the photomultiplier tube. Accordingly, it is possible to provide a radiation detector capable of accurately discriminating the position without lowering the output and maintaining high image quality with high resolution.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a radiation detector according to a first embodiment of the present invention.
FIG. 2 is a diagram showing an example of a radiation detector according to the first embodiment of the present invention.
FIG. 3 is a block diagram of a position detector of the radiation detector of the present invention.
FIG. 4 is a diagram illustrating an example of a radiation detector according to a second embodiment of the present invention.
FIG. 5 is a diagram showing an example of a radiation detector according to a third embodiment of the present invention.
FIG. 6 is a diagram showing a conventional example of a radiation detector.
[Explanation of symbols]
1, 2, 3, 4, ... adders
5, 6… Position discrimination circuit
10 ... Scintillator group
10 _i1 -10 _i10 (I = an integer from 1 to 10) ... scintillators arranged in the X direction
10 _1j -10 _10j (J = an integer from 1 to 10) ... scintillators arranged in the Y direction
11 ... close contact surface
20 ... Light guide
21 ... Reflection member
22 ... void
23. Sealing film
24 ... Input surface
30 Photomultiplier tube
31 ₁ , 31 ₂ ... Photocathode
32 ... face plate
34 ... Partition plate
40 ... Photomultiplier tube
41 ₁ , 41 ₂ ... Photocathode
42 ... face plate
44 ... Partition plate
120… Light guide
121 ... Reflection member
122 ... void
125 ... Output surface
126 ... Sealing film
220 ... Light guide
221 ... reflective member
222 ... void
223: Sealing film
224 ... Input surface
225 ... Output surface
226: Sealing film

Claims (8)

A plurality of scintillators closely arranged two-dimensionally; a light guide optically coupled to the scintillator; and a photocoupler optically coupled to the light guide and having less than the number of the scintillators In a radiation detector provided with a plurality of photomultiplier tubes having the number of surface poles, the light guide is partitioned by a plurality of voids formed from a coupling surface side with a scintillator. Detector. 2. The radiation detector according to claim 1, wherein the light guide is partitioned by a plurality of gaps formed from a coupling surface side with the photomultiplier tube. 2. The radiation detector according to claim 1, wherein the light guide is partitioned by a plurality of gaps formed from both sides of a coupling surface with the scintillator and a coupling surface with the photomultiplier tube. Radiation detector. The radiation detector according to any one of claims 1 to 3, wherein the light guide is formed from a coupling surface side with the scintillator or a coupling surface side with the photomultiplier tube or both sides thereof, and a gap and a light shielding member. A radiation detector characterized by being partitioned by a combination of: 5. The radiation detector according to claim 4, wherein the light blocking member is provided at a periphery of the section. The radiation detector according to claim 5, wherein an optically-coupling material is inserted into at least a part of the space except for a peripheral portion of the section. The radiation detector according to any one of claims 1 to 5, further comprising a sealing member for preventing foreign matter from entering a gap provided in the light guide. Radiation detector. The radiation detector according to claim 7, wherein the sealing member is a sealing film made of a light transmitting material.

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