JP2017015627A - Scintillator array and method for manufacturing the same, and radiation detector and radiation inspection device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scintillator array which corresponds to miniaturization and high definition of a detector, reduces a crosstalk between scintillator elements, reduces dispersion in light output of the detector, and enhances positioning accuracy with a photodiode for detecting light, and to provide a method for manufacturing the same.SOLUTION: There is provided a scintillator array, which has a plurality of ceramic scintillator elements that are sintered bodies of a fluorescent body of any one of a rare-earth acid sulfide, garnet and a composite sulfide, and a reflection layer that is provided so as to integrate these elements and has a resin of which a glass transition point is set at a temperature higher than a use temperature range, where a surface of the scintillator element in contact with the reflection layer is mirror-finished, a crosstalk of light emitted by incident X-rays is 20% or less with an output ratio of adjacent elements, and accuracy of an external dimension is enhanced.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ceramic scintillator array for converting radiation such as X-rays into visible light, a method for manufacturing the same, and a radiation detector and a radiation inspection apparatus using the same.

In fields such as medical diagnosis and industrial nondestructive inspection, X-ray tomography equipment (hereinafter referred to as X-ray CT)
An inspection using a radiation inspection apparatus such as an apparatus) is performed. The X-ray CT system uses an X-ray tube (X-ray source) that irradiates a fan-shaped fan beam X-ray and an X-ray detector with a large number of X-ray detection elements, with the tomographic plane of the object to be inspected at the center. It is configured to face each other. In the X-ray CT apparatus, fan beam X-rays are irradiated from an X-ray tube while rotating the object to be inspected, and X-ray absorption data transmitted through the object to be inspected are collected by an X-ray detector. Thereafter, the tomogram is reproduced by analyzing the X-ray absorption data with a computer.
A detection element using a solid scintillator is widely used in the radiation detector of this X-ray CT apparatus. In a radiation detector using a solid scintillator, it is possible to reduce the size of the detection element and increase the number of channels, so that the resolution of the X-ray CT apparatus can be further increased.

Japanese Patent No. 4558457

Among the above-mentioned various solid scintillators, phosphor ceramics of any one of rare earth oxysulfides, garnets, and composite sulfides have high luminous efficiency and have characteristics suitable for scintillators. For this reason, radiation detectors combining a ceramic scintillator of a phosphor of any one of rare earth oxysulfides, garnets, and composite sulfides and a photodiode are becoming widespread.

Such ceramic scintillator materials (phosphor ceramics) are rare earth oxysulfides,
It is produced by molding a phosphor powder of any one of garnet and composite sulfide into a predetermined shape and sintering it. A rectangular bar-shaped or flat scintillator plate is cut out from the obtained sintered body, and this scintillator plate is further sliced into a plurality of scintillator elements. The detection element of the radiation detector is constituted by, for example, a scintillator array in which a plurality of scintillator elements are integrated.
In recent X-ray CT apparatuses, the detector output has been increased due to the downsizing of the detection element accompanying higher resolution (multi-channel) and the lowering of X-ray exposure to the object to be inspected. It has been demanded.
Conventionally, the detection element is manufactured by forming a groove in a block of a laminated structure of a scintillator plate and a reflective layer by machining such as a slicer, and filling the groove with a resin containing a reflective agent,
A rod-shaped scintillator plate is arranged with a predetermined gap, and a white PET plate serving as a reflective layer is inserted into the gap, or a resin containing a reflective agent is filled.
Along with the downsizing of the detection element as described above, as a method for manufacturing the element, grooves are formed by machining such as a slicer in two orthogonal directions of a flat scintillator, and the groove part is filled with a resin containing a reflective agent. It is also manufactured. (For example, see Patent Document 1)
According to such machining, it is possible to process a groove having a narrow width of 0.1 mm or less, and the groove is formed with high accuracy, and therefore, the minute scintillator element in which the width of the reflective layer formed in the groove is small. It became possible to form. However, since the width of the reflective layer is narrow,
Crosstalk, which is light leakage caused by the light emitted by the radiation incident on the scintillator elements, leaks to the adjacent scintillator elements, and the output difference between the scintillator elements of the scintillator array is reduced. Becomes worse and the image becomes blurred.

In recent years, it has become necessary to further reduce the size and definition of the detection element. Accordingly, for example, a phosphor ceramic scintillator obtained by a sintering process has a width of 20 mm or more, a length of 100 mm or more, and a thickness of 0.5 mm. It is necessary to cut a scintillator plate having such a size as described above to produce a fine scintillator element having a length of 1 mm or less, a width of 1 mm or less, and a gap width (width of the reflection layer) of 0.08 mm or less.
In the scintillator array composed of these fine scintillator elements, crosstalk, which is the light leakage to the adjacent scintillator elements as described above, becomes large, and the dimensional variation of the scintillator array has been large conventionally. There is a problem that the alignment accuracy with the photodiode that detects the emitted light is low.

As the resolution of X-ray CT apparatuses increases, artifacts (pseudo images) that appear when X-ray absorption data that has passed through an object to be analyzed are analyzed by a computer and a tomographic image is reproduced have become a problem. Artifacts are caused by local sensitivity non-uniformity of ceramic scintillator elements. When an artifact appears, it becomes an obstacle to medical diagnosis and non-destructive inspection. Therefore, as the scintillator element is reduced in size as described above, further reduction in characteristic variation is desired.

The present invention has been made in order to address the above-described problems, and is a cross that is light leakage to adjacent elements between scintillator elements that can cope with further downsizing, higher definition, etc. of recent detectors. Reduces in-plane variation in detector light output by reducing talk and reducing non-uniformity,
An object of the present invention is to provide a ceramic scintillator array with improved alignment accuracy with a photodiode for detecting light emitted from the element, and a method for manufacturing the same. Furthermore, by using the ceramic scintillator array as described above, there are provided a radiation detector and a radiation inspection apparatus that improve resolution and image accuracy, thereby improving medical diagnostic ability and nondestructive inspection accuracy with low exposure. The purpose is that.

A plurality of ceramic scintillator elements that are sintered bodies of phosphors of any one of rare earth oxysulfides, garnets, and composite sulfides, and the plurality of scintillator elements are integrated between the plurality of scintillator elements. A value obtained by dividing the area of the scintillator element by the width of the reflective layer portion surrounding the scintillator element, and the light emitted by the incident X-rays is adjacent to the scintillator array. When light leaks to the scintillator element (crosstalk), a slit with a width of 0.1 mm is installed on the scintillator element, and the element emits light with 120 kV X-rays that have passed through the slit. Is a ceramic scintillator array characterized by being 20% or less.
The scintillator array is a ceramic scintillator array characterized in that the surface of the scintillator element in contact with the reflective layer has a mirror finish.
The scintillator array is a ceramic scintillator array in which the surface of the scintillator element in contact with the reflective layer is polished by any one of # 800 finer polishing paper, buffing, or polishing with a diamond grindstone. .
In the scintillator array, the root mean square surface roughness Rq of the surface of the scintillator element in contact with the reflective layer is 5 μm or less.
The scintillator array has an outer dimension variation of ± 0.03% or less of the outer dimension.
The scintillator array has a dimensional change rate with temperature of 2.5 μm / ° C. or less. Preferably, it is 2.0 μm / hour or less.
The scintillator array has a dimensional change rate of 0.2 μm / hour or less even when transported or stored in an environment of high temperature (25 ° C. or more) and humidity (humidity of 80% RH or more). Preferably, it is 0.1 μm / hour or less.
The scintillator array is characterized in that the glass transition point of the resin constituting the reflective layer portion is set to a temperature higher than the operating temperature range.
A ceramic scintillator that is a sintered body of a phosphor of any kind of rare earth oxysulfide, garnet, or composite sulfide is processed into a plurality of pieces, and a block formed of a reflective layer is grooved. A method of manufacturing a ceramic scintillator array, wherein a plurality of pieces are inserted into the grooves of the reflective layer and bonded together.
In the method of manufacturing the scintillator array, the surface of the scintillator element formed from the scintillator piece is mirror-finished to provide a mirror finish.
In the method of manufacturing the scintillator array, the surface in contact with the reflective layer of the scintillator element formed from the scintillator piece is polished by any one of # 800 finer polishing paper, buffing, or polishing with a diamond grindstone. This is a method for manufacturing a ceramic scintillator array.

The figure which shows an example of the side surface of the scintillator array concerning embodiment. The figure which shows an example of the upper surface of the scintillator array concerning embodiment. The figure which shows an example of the X-ray detector concerning embodiment. The figure which shows another example of the X-ray detector concerning embodiment. 1 is a diagram showing an example of an X-ray inspection apparatus according to an embodiment. The figure which shows an example of the manufacturing process of the scintillator array concerning embodiment.

The scintillator array according to the embodiment of the present invention is composed of a sintered body (phosphor ceramic) of a rare earth oxysulfide phosphor containing praseodymium (Pr) as an activator. Examples of rare earth oxysulfide phosphor materials include yttrium (Y), gadolinium (Gd),
Examples thereof include oxysulfides of rare earth elements such as lanthanum (La) and lutetium (Lu). One kind of phosphor of garnet or composite sulfide is also used.

A scintillator array according to an embodiment of the present invention includes a plurality of scintillator elements and a reflective layer portion provided between the plurality of scintillator elements so as to integrate the plurality of scintillator elements. A scintillator array according to an embodiment of the present invention includes a plurality of pieces of ceramic scintillators that are sintered bodies of phosphors of rare earth oxysulfide, garnet, or composite sulfide containing praseodymium as the activator. The ceramic scintillator array is characterized in that a plurality of pieces of the scintillator are inserted into and bonded to the grooves of the reflective layer block after the block made of the reflective layer is processed into a groove and processed into a groove. Before inserting and bonding multiple pieces of the scintillator in the groove of the layer, the surface of the piece that contacts the reflective layer is mirror-finished, thereby suppressing light scattering at the reflective layer interface and crosstalk between elements. The ceramic scintillator array is characterized in that it is reduced and variation between elements of characteristics such as light output is reduced.

The resin constituting the reflective layer contains a first metal oxide made of titanium oxide and a second metal oxide made of a metal oxide other than titanium oxide. Furthermore, the resin constituting the reflective layer is characterized in that the glass transition point is set to a temperature higher than the operating temperature range of the scintillator array.

FIG. 1 shows an example of a side surface of the scintillator array according to the embodiment. FIG. 2 shows an example of the upper surface of the scintillator array according to the embodiment. The scintillator array 1 has a plurality of scintillator elements 2. A reflective layer portion 3 is provided between the plurality of scintillator elements 2. The reflective layer portion 3 is directly bonded to the scintillator element 2. The plurality of scintillator elements 2 are integrated by the reflective layer portion 3. That is, the scintillator array 1 includes a plurality of scintillator elements 2 and a reflective layer portion 3 provided between the plurality of scintillator elements 2 so as to integrate the plurality of scintillator elements 2.

The scintillator array 1 includes a structure having a plurality of scintillator elements 2 arranged in a line, or a plurality of scintillator elements 2 arranged two-dimensionally in a predetermined number in the vertical and horizontal directions as shown in FIG. You may have the structure to comprise. Multiple scintillator elements 2
Are two-dimensionally arranged, the reflective layer portions 3 are provided between the vertical and horizontal scintillator elements 2, respectively. The number of scintillator elements 2 is appropriately set according to the structure and resolution of the X-ray detector. The scintillator array 1 has a multi-channel structure.
Furthermore, the surface in contact with the reflective layer portion 3 of the scintillator element 2 is mirror finished,
Light scattering at the reflective layer interface is suppressed to reduce crosstalk between elements and to reduce variations in characteristics such as light output.

The surface of the scintillator array 1 in contact with the reflective layer portion 3 of the scintillator element 2 has a root mean square roughness Rq (according to JIS B0601: 2013) of 5 μm or less.

The reflective layer part 3 is comprised by the resin part containing a metal oxide. The resin portion includes a first metal oxide made of titanium oxide (titanium oxide particles) and a metal oxide other than titanium oxide (aluminum oxide A).
and a second metal oxide made of i2O3 or the like.

The resin part preferably contains, for example, a thermosetting resin. As the thermosetting resin, for example, one selected from the group consisting of epoxy resins, silicone resins, phenol resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, polyurethane resins, and polyimide resins is preferable. Among these resins, it is more preferable to use an epoxy resin or a silicone resin. Epoxy resins or silicone resins are preferred because of their high photocatalytic resistance. Furthermore, the glass transition point of the resin constituting the reflective layer is higher than the operating temperature range of the scintillator array. The glass transition point is preferably 70 ° C. or higher.

The thickness T of the scintillator element 2 is preferably in the range of 0.5 to 3 mm, and more preferably in the range of 1 to 2 mm. The thickness T of the scintillator element 2 is 0.5 mm
If it is less than the range, the X-ray component transmitted through the scintillator element 2 increases and the light output may be lowered. Even if the thickness T of the scintillator element 2 exceeds 3 mm, it is difficult to obtain further improvement in light output, which causes an increase in manufacturing cost. As shown in FIG. 2, when the scintillator elements 2 are arranged two-dimensionally, it is preferable that both the lengths in the vertical direction and the horizontal direction are in the range of 0.5 to 2 mm.

The width W of the reflective layer portion 3 (distance between adjacent scintillator elements 2 / width W in FIG. 1) is 10 to 1.
A range of 00 μm is preferable. The width W of the reflective layer part 3 is not particularly limited as long as the scintillator element 2 is arranged on a pixel of a photoelectric conversion element described later. However, when the width W of the reflective layer portion 3 is less than 10 μm, the function of the reflective layer portion 3 as an adhesive layer is lowered, and the adhesive strength of the reflective layer portion 3 to the scintillator element 2 is likely to be lowered. As a result, the strength of the scintillator array 1 may be reduced. The width of the reflective layer part 3 is 100 μm
If it exceeds, the scintillator array 1 becomes larger than necessary. The width W of the reflective layer portion 3 is more preferably in the range of 20 to 80 μm. In the scintillator array 1 shown in FIG. 2, the width W of the reflective layer portion 3 may not be the same in the vertical direction and the horizontal direction. A value obtained by dividing the area of the scintillator element by the width of the reflective layer portion surrounding it is 4500 or more. If it is less than 4500, the crosstalk becomes larger than 20%.

Next, an X-ray detector and an X-ray inspection apparatus according to an embodiment will be described with reference to the drawings.
3 and 4 are diagrams showing the configuration of the X-ray detector according to the embodiment. The scintillator array 1 has a surface 1a serving as an X-ray irradiation surface, and a photoelectric conversion element 4 is integrally installed on a surface 1b opposite to the surface 1a. As the photoelectric conversion element 4, for example, a photodiode is used. The photoelectric conversion element 4 is disposed at a position corresponding to the scintillator element 2 constituting the scintillator array 1. As shown in FIG. 4, a surface reflection layer 6 may be provided on the surface 1 a of the scintillator array 1. These components constitute the X-ray detector 5.

The surface reflection layer 6 is not limited to the surface 1 a of the scintillator array 1, and may be provided on the surface 1 b that is an installation surface of the photoelectric conversion element 4. Further, the surface reflection layer 6 is formed on the surface 1 of the scintillator array 1.
It may be provided on both a and the surface 1b. By providing the surface reflection layer 6 on the scintillator array 1, the reflection efficiency of visible light emitted from the scintillator element 2 is further improved,
As a result, the light output of the scintillator array 1 can be increased. For the surface reflective layer 6, a mixture of reflective particles and a transparent resin, a lacquer-based paint, or the like is used. The mixture of the reflective particles and the transparent resin preferably has the same dispersed state of the reflective particles as the reflective layer portion 3. The thickness of the surface reflective layer 6 is preferably in the range of 50 to 250 μm. If the thickness of the surface reflective layer 6 is less than 50 μm, the effect of improving the reflection efficiency cannot be sufficiently obtained. The thickness of the surface reflection layer 6 is 250.
When it exceeds μm, the transmitted X-ray dose decreases and the detection sensitivity decreases.

FIG. 5 shows an X-ray CT apparatus 10 which is an example of the X-ray inspection apparatus of the embodiment. X-ray CT
The apparatus 10 includes the X-ray detector 5 according to the embodiment. The X-ray detector 5 is affixed to the inner wall surface of a cylinder that rests the imaging region of the subject 11. An X-ray tube 12 that emits X-rays is installed at substantially the center of the circular arc of the cylinder to which the X-ray detector 5 is attached. A subject 11 is disposed between the X-ray detector 5 and the X-ray tube 12. On the X-ray irradiation surface side of the X-ray detector 5, a collimator (not shown) is provided.

The X-ray detector 5 and the X-ray tube 12 are configured to rotate while imaging with X-rays around the subject 11. Image information of the subject 11 is collected three-dimensionally from different angles. A signal obtained by X-ray imaging (electric signal converted by the photoelectric conversion element) is processed by the computer 13 and displayed as a subject image 15 on the display 14. The subject image 15 is a tomographic image of the subject 11, for example. As shown in FIG. 2, a multi-tomographic X-ray CT apparatus 10 can be configured by using a scintillator array 1 in which scintillator elements 2 are two-dimensionally arranged. In this case, a plurality of tomographic images of the subject 11 are simultaneously photographed, and for example, the photographing result can be depicted in three dimensions.

An X-ray CT apparatus 10 shown in FIG. 5 includes an X-ray detector 5 having the scintillator array 1 of the embodiment. As described above, the scintillator array 1 of the embodiment has an excellent light output because the reflection efficiency of visible light emitted from the scintillator element 2 is high based on the configuration of the reflective layer portion 3 and the like. By using the X-ray detector 5 having such a scintillator array 1, the imaging time by the X-ray CT apparatus 10 can be shortened. As a result, the exposure time of the subject 11 can be shortened, and low exposure can be realized.
The X-ray inspection apparatus (X-ray CT apparatus 10) of the embodiment is applicable not only to an X-ray inspection for medical diagnosis of a human body but also to an X-ray inspection of an animal, an X-ray inspection for industrial use, and the like. .

The scintillator array 1 of the embodiment is manufactured as follows, for example. A method for efficiently manufacturing the scintillator array 1 of the embodiment will be described below. The manufacturing method of the scintillator array 1 of embodiment is not limited to this. The scintillator array 1 only needs to have the above-described configuration, and is not limited to the manufacturing method.

First, titanium oxide particles having an average particle size of 2 μm or less are prepared. Titanium oxide particles are 0.2 ~
It is preferable to have a particle size distribution with a peak in the range of 0.3 μm. The titanium oxide particles preferably have a rutile structure.

Next, a metal oxide to be a second metal oxide is prepared. When adding a 2nd metal oxide as a metal oxide particle, it is preferable to use a metal oxide with an average particle diameter of 2 micrometers or less. Moreover, when providing a surface film in a titanium oxide particle, a surface treatment process is performed. Surface treatment process is chlorine method, chemical vapor deposition (CVD)
Method, physical vapor deposition (PVD) method, colloid method and the like. Moreover, the amount of the 2nd metal oxide used as the surface film can be calculated | required by comparing the mass of the titanium oxide particle before a surface treatment process, and the mass of the titanium oxide particle with a surface film after a surface treatment. Also, X-ray diffraction (X-Ray Diffracti
on: XRD) analysis can also determine the mass ratio of titanium oxide to the second metal oxide from the peak ratio of the titanium oxide peak to the second metal oxide peak. In addition, X-ray fluorescence analysis (
Analysis by X-ray Fluorescence (XRF) is also possible.

Next, when the total of the titanium oxide particles and the second metal oxide is 100 parts by mass, the titanium oxide particles are 70 to 84 parts by mass and the second metal oxide is 30 to 16 parts by mass. When adding a 2nd metal oxide only by a metal oxide particle, it mix | blends so that the mass of a titanium oxide particle and the mass of a 2nd metal oxide particle may become the target ratio. In addition, when both the surface-coated titanium oxide particles and the second metal oxide particles are present, the amount of the second metal oxide film in the surface-coated titanium oxide particles is obtained in advance, and the deficiency is second metal oxidized. Formulated as product particles.
Moreover, when it respond | corresponds only by the titanium oxide particle with a surface coating, only the titanium oxide particle with a surface coating is prepared.

In order to prevent aggregation of titanium oxide particles and the like in the reflective layer portion 3, it is preferable to previously pulverize the aggregates of titanium oxide particles with an ultrasonic vibrator or the like. Moreover, it is preferable that the impurity component amount in a titanium oxide particle is 1 mass% or less. Next, a resin is prepared. The resin is preferably a resin such as the epoxy resin and silicone resin described above. The epoxy resin is more preferably a two-pack type epoxy resin.

Reflective particles such as titanium oxide particles and a resin such as an epoxy resin are mixed. In the case of a two-component epoxy resin, the epoxy resin main agent and reflective particles such as titanium oxide particles are mixed. The reflective particles (titanium oxide particles, second metal oxide particles, or titanium oxide particles with a surface coating) are preferably dispersed uniformly in the resin. For uniform dispersion, it is preferable to mix using three rolls. The three-roll is a mixer that uses three rolls for mixing. Since the three rolls are moved and mixed at the same time, the mixing direction becomes a plurality of directions, and it becomes difficult to form aggregates during the mixing process. The mixing step using three rolls is preferably performed for 10 hours or more.
Moreover, it is also effective to mix the organic resin by reducing the viscosity of the transparent resin as necessary. When mixing the reflective particles with the transparent resin, it is preferable not to mix all the reflective particles at once, but to mix them little by little (for example, one third).

Below, the manufacturing method of the scintillator array of embodiment is demonstrated with reference to FIG.
A resin layer (resin mixture) in which the reflective particles are mixed is cured to a predetermined size to form a reflective layer block 1
6 is created. The reflective layer block 16 is grooved to a certain depth to form a grooved reflective layer block (1) 17. Create a plurality of scintillator pieces 19 cut out from the sintered body,
After the surface of each scintillator piece in contact with the reflective layer portion is mirror-finished, it is fitted into the groove portion (1) 18 of the grooved reflective layer block 17 and bonded and integrated 20. After being integrated 20, the upper and lower surfaces having a large area are polished (1) 21 and processed so that the reflective layer has a shape penetrating the front and back of the scintillator array 1. Further, cutting is performed in a direction perpendicular to the reflective layer portion to create a plurality of pieces in which scintillator elements and reflective layers are alternately arranged. Then, a grooved reflective layer block (2) is formed, and the surface in contact with the reflective layer portions of the plurality of pieces in which the scintillator elements and the reflective layers are alternately arranged is mirror finished, and then the grooved reflective layer block ( 2) Fit into the groove part (2) 24 of 23 and bond and integrate (2) 25. Furthermore, it grind | polishes (2) 26 and processes it so that a reflection layer part may have the shape which penetrates the front and back of the scintillator array 1. FIG.

The polishing may be performed on one side or both sides of the scintillator. The scintillator is polished by any of polishing paper, buffing, and polishing with a diamond grindstone that is finer than # 800. When abrasive paper is used, abrasive paper of # 1000 or less is preferable. A polishing paper of # 2000 or less is more preferable. Moreover, it is preferable to carry out so that the root mean square roughness Rq of the scintillator is Rq 5 μm or less.

After the polishing, an etching process is performed to remove a damaged layer due to polishing. This etching treatment is preferably performed with a mixed solution of water, sulfuric acid, and hydrogen peroxide. This mixed solution is more preferably mixed at a volume ratio of water: sulfuric acid: hydrogen peroxide = 10: 2: 1.

(Examples 1-3, Comparative Examples 1-4)
As a scintillator, a gadolinium oxysulfide sintered body (Gd ₂ O ₂ S: Pra, a = 0.0
A plate material (width 30 mm × length 80 mm × thickness 0.5 mm) comprising 1) was prepared. Next, it processed with the dicer so that the size of each scintillator piece from the said sintered compact might become width 30.0mm x length 1.3mm x thickness 0.5mm. After the dicer processing, a strain relief heat treatment was performed.

Next, titanium oxide particles were prepared as reflective particles. Titanium oxide particles having an average particle size of 0.2 μm and a particle size distribution peak of 0.22 μm were prepared. In addition, the rutile type titanium oxide particles were prepared.

Next, aluminum oxide (Al ₂ O ₃ ) particles, zirconium oxide (ZrO ₂ ) particles, tantalum oxide (Ta ₂ O ₅ ) particles, and silicon oxide (SiO 2) particles were prepared as the second metal oxide. The second metal oxide particles were prepared with an average particle size of 0.3 μm. Titanium oxide particles and second metal oxide particles were mixed. The mixed powder was subjected to an ultrasonic vibrator to sufficiently pulverize the aggregate.

Next, a two-pack type epoxy resin is prepared, mixed powder is added, and it is 20-5 with a three roll mixer.
A 0 hour mixing step was performed. The viscosity of the obtained resin mixture was adjusted to be in the range of 0.5 to 2.5 Pa · s. In the resin mixture, when the epoxy resin was 100 parts by mass, the mass of the reflective particles (the total of the titanium oxide particles and the second metal oxide particles) was 1.5 parts by mass.

Resin mixed with the reflective particles (resin mixture) is a predetermined dimension (width 30 mm × length 80 mm ×
A reflective layer block is prepared by curing to a thickness of 0.8 mm. The reflective layer block was grooved to a certain depth to form a grooved reflective layer block.

The surface in contact with the reflective layer of the plurality of scintillator pieces prepared as described above is polished with # 2000 polishing paper to give a mirror finish, and then is subjected to predetermined etching conditions (etching solution; water: sulfuric acid: hydrogen peroxide solution = 10). : 2: 1, etching temperature = 35 ° C., etching time = 5 minutes), and scintillator arrays according to Examples and Comparative Examples were manufactured.
Table 1 shows the production conditions of Examples 1 to 7 and Comparative Examples 1 to 3. Note that the value obtained by dividing the area of the scintillator element by the width of the reflective layer portion surrounding it was 4500 or more.

For scintillator arrays according to Examples 1 to 3 and Comparative Examples 1 to 4, the external dimensions, 30 ° C.
Change in external dimensions after holding at 80% RH for 120 hours, external dimensions when held at a temperature of 50 ° C., and a slit with a width of 0.1 mm placed on the scintillator element and passed through the slit of 120 kV
The output ratio of adjacent elements was measured when the elements were made to emit light by X-rays. The measurement results are shown in Table 2.

As can be seen from Table 2, the scintillator array according to the example has little crosstalk of the light output, and the variation in the external dimensions is also small.

As described above, the scintillator array according to the embodiment has less crosstalk of light output and less variation in external dimensions, and is superior to the comparative example which is a conventional product. Therefore, an excellent scintillator array can be obtained. Therefore, it can be seen that the X-ray detector and the X-ray inspection apparatus using the scintillator array of the embodiment have high reliability.

As mentioned above, although several embodiment of this invention was illustrated, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and without departing from the spirit of the invention,
Various omissions, replacements, changes, etc. can be made. These embodiments and their variations are
The invention is included in the scope and gist of the invention, and is included in the invention described in the claims and the equivalent scope thereof. Further, the above-described embodiments can be implemented in combination with each other.

DESCRIPTION OF SYMBOLS 1 ... Scintillator array 1a ... X-ray irradiation surface of scintillator array 1b ... Surface on the opposite side of X-ray irradiation surface of scintillator array 2 ... Scintillator element, T: Thickness of element 3 ... Reflection layer part, W : Reflection layer width 4 ... photoelectric conversion element 5 ... X-ray detector 6 ... surface reflection layer 10 ... X-ray CT apparatus 11 ... subject 12 ... X-ray tube 13 ... computer 14 ... Display 15 …… Subject image 16 …… Reflection layer block 17 …… Grooving reflection layer block (1)
18 …… Groove (1)
19 …… Scintillator piece 20 …… Integration (1)
21 …… Polishing (1)
22 …… Cut 23 …… Grooving reflective layer block (2)
24 …… Groove (2)
25 …… Integration (2)
26 ... Polishing (2)

Claims (19)

A plurality of ceramic scintillator elements that are sintered bodies of phosphors of any one of rare earth oxysulfides, garnets, and composite sulfides, and the plurality of scintillator elements are integrated between the plurality of scintillator elements. A value obtained by dividing the area of the scintillator element by the width of the reflective layer portion surrounding the scintillator element, and the light emitted from the incident X-rays is adjacent to the scintillator array. When light leaks to the scintillator element (crosstalk), an output of an adjacent element when a slit having a width of 0.1 mm is installed on the scintillator element and the element is caused to emit light by 120 kV X-rays passing through the slit. A ceramic scintillator array having a ratio of 20% or less. 2. The ceramic scintillator array according to claim 1, wherein the scintillator array has a mirror-finished surface in contact with the reflective layer of the scintillator element. 2. The scintillator array, wherein the surface of the scintillator element that contacts the reflective layer is polished by at least one of polishing paper with a finer count than # 800, buffing, or polishing with a diamond grindstone. The ceramic scintillator array according to any one of claims 2 to 3. 4. The ceramic scintillator array according to claim 1, wherein the scintillator array has a root mean square surface roughness Rq of 5 μm or less of a surface in contact with the reflective layer of the scintillator element. 5. . The ceramic scintillator array according to claim 1, wherein the scintillator array has an outer dimension variation of ± 0.03% or less of the outer dimension. The ceramic scintillator array according to any one of claims 1 to 5, wherein the scintillator array has a dimensional change rate with temperature of 2.5 µm / ° C or less. The dimensional change rate with time is 0.2 μm / hour or less even if the scintillator array is transported or stored in a high temperature (25 ° C. or higher) and high humidity (humidity 80% RH or higher) environment. The ceramic scintillator array according to any one of claims 1 to 6. The ceramic scintillator array according to any one of claims 1 to 7, wherein the scintillator array has a glass transition point of a resin constituting the reflection layer portion higher than a use temperature range. The ceramic scintillator array according to any one of claims 1 to 8, wherein the scintillator array has a glass transition point of a resin constituting the reflective layer portion of 70 ° C or higher. 10. The method of manufacturing a scintillator array according to claim 1, wherein a ceramic scintillator that is a sintered body of a phosphor of any one of a rare earth oxysulfide, a garnet, and a composite sulfide is formed into a plurality of pieces. A method of manufacturing a ceramic scintillator array, comprising: processing and grooving a block composed of a reflective layer; and inserting and bonding a plurality of pieces of the scintillator into the groove of the reflective layer. 11. The method of manufacturing a ceramic scintillator array according to claim 10, wherein in the method of manufacturing a scintillator array, a surface of the scintillator element formed from the scintillator piece is mirror-finished. In the method of manufacturing the scintillator array, the surface in contact with the reflective layer of the scintillator element formed from the scintillator piece is polished by any one of # 800 finer polishing paper, buffing, or polishing with a diamond grindstone. 12. The method of claim 11, wherein
The manufacturing method of the ceramic scintillator array of description. The ceramic scintillator according to any one of claims 10 to 12, wherein the scintillator array is processed so that a root mean square surface roughness Rq of a surface in contact with the reflective layer of the scintillator element is 5 µm or less. Array manufacturing method. 14. The method of manufacturing a scintillator array, wherein at least one of plasma treatment and corona discharge treatment is performed on a surface of the scintillator element formed from the scintillator piece in contact with a reflective layer. A method for producing a ceramic scintillator array according to claim 1. A ceramic scintillator array according to any one of claims 1 to 9,
Fluorescence generating means for emitting light from the ceramic scintillator array in response to incident radiation, and photoelectric conversion means for receiving light from the fluorescence generating means and converting the output of the light into an electrical output Radiation detector. The fluorescence generating means has a scintillator array configured by stacking a plurality of elements in vertical and horizontal directions, which are produced by processing a scintillator plate made of the ceramic scintillator material by at least one of slicing and grooving. The radiation detector according to claim 15. The fluorescence generating means includes a plurality of channels, and each of the plurality of channels has a configuration in which a plurality of segments prepared by slicing the scintillator material are integrated in a direction substantially perpendicular to the arrangement direction of the plurality of channels. The radiation detector according to claim 15, wherein the radiation detector is a radiation detector. A radiation source for irradiating radiation toward the object to be inspected and a radiation detector according to any one of claims 15 to 17 for detecting the radiation transmitted through the object to be inspected. Characteristic radiological examination apparatus. The radiation inspection apparatus according to claim 18, wherein the radiation inspection apparatus is an X-ray tomography apparatus.

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