JP2020201163A - Radiation detection powder and method of manufacturing the same, and radiographic inspection paper with radiation detection powder and method of manufacturing the same - Google Patents

Abstract

To make it easy to detect a radiation with higher detection sensitivity, and to enable low-cost mass-production.SOLUTION: Radiation detection powder contains a scintillator which is excited with a radiation to emit light, wherein the scintillator is a composite of organic scintillator molecules and silica nano-particles, and the composite has an aromatic ring, by organic scintillator molecules included in an inclusion compound, or the organic scintillator molecules and a coupling agent, fixed inside or on surfaces of the silica nano-particles by a sol-gel method. Radiographic inspection paper comprising radiation detection powder containing a scintillator which is excited with a radiation to emit light, comprises a paper-made sheet-like base material 1 made in a sheet shape, and a coating layer 6 covering a surface of the sheet-like base material 1 by coating and containing the radiation detection powder 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a radiation detection powder containing a scintillator that is excited by radiation and emits light and a method for producing the same, and a radiation test paper provided with the radiation detection powder and a method for producing the same.

In recent years, as a radiation detection material, an imaging plate (IP) that enables two-dimensional imaging of radiation dose has attracted attention. However, at present, IP is very expensive and has a quantitative problem due to fading, attenuation of fluorescence amount, and the like. In addition, since IP requires a laser beam for detection, there is also a problem that it cannot be measured at a radioactive contamination site. Furthermore, once IP is contaminated with radioactive material, it becomes radioactive waste. This can be avoided by covering the IP with a pollution prevention film, but when detecting a sample such as tritium whose emitted radiation (β rays) is low energy, it is difficult to detect it by covering it with the film. Become. Therefore, when detecting a sample such as tritium, the expensive IP had to be thrown away.

On the other hand, as a radiation detection material other than IP, a method of using a liquid scintillator in which an organic scintillator is dissolved in an organic solvent has been proposed. This liquid scintillator has the characteristic that it can measure even low levels of radiation. However, since this liquid scintillator is water-insoluble, it has a drawback that it cannot be used for measuring water, and there is a problem in the storage and treatment of radioactive organic waste liquid after use.

JP 2011-214882

The present invention has been made in view of such a background. One of the objects of the present invention is a radiation detection powder that can be easily detected in large quantities at low cost while increasing the detection sensitivity of radiation, a method for producing the same, and a radiation test paper provided with the radiation detection powder. The purpose is to provide a manufacturing method.

Means for Solving Problems and Effects of Invention

The radiation detection powder according to the first embodiment of the present invention is a radiation detection powder containing a scintillator that is excited by radiation and emits light. The scintillator is a composite of an organic scintillator molecule and silica nanoparticles, and this composite is , The organic scintillator molecule or the organic scintillator molecule encapsulated with the inclusion compound, and the aromatic ring by the coupling agent are fixed to the inside or the surface of the silica nanoparticles by the sol-gel method.

In the radiation detection powder according to the second aspect of the present invention, the complex contains two or more kinds of organic scintillator molecules.

Further, in the radiation detection powder according to the third embodiment of the present invention, the clathrate compound is a cyclic oligosaccharide and the coupling agent is a silane coupling agent.

The method for producing a radiation detection powder according to a fourth aspect of the present invention is a method for producing a radiation detection powder containing a scintillator that is excited by radiation and emits light, and contains an organic scintillator molecule and an inclusion compound in an organic solvent. In addition, a silicic acid source and a cup are added to the first mixing step of heating and dissolving the organic scintillator molecule or the organic scintillator molecule encapsulated with the inclusion compound in the organic solvent, and the first mixing solution obtained in the first mixing step. The ring agent is added and heated and stirred, and the organic scintillator molecule is fixed to the inside or the surface by the sol-gel method, and silica nanoparticles having the aromatic ring fixed to the inside or the surface are formed by the coupling agent to form the organic scintillator molecule. It includes a second mixing step of forming a composite of the scintillator and the silica nanoparticles, and a heating and drying step of heating and drying the second mixed solution obtained in the second mixing step to obtain a radiation detection powder.

In the method for producing a radiation detection powder according to a fifth embodiment of the present invention, the clathrate compound is a cyclic oligosaccharide, the coupling agent is a silane coupling agent, and the silicic acid source is tetraethyl orthosilicate or tetramethyl orthosilicate. , Tetrapropyl orthosilicate.

The radiation test paper according to the sixth embodiment of the present invention is a radiation test paper including a radiation detection powder containing a scintillator that is excited by radiation and emits light, and is a sheet-like base material made of paper that is made into a sheet. And a coating layer containing a radiation detection powder coated on the surface of the sheet-like substrate. The radiation detection powder is composed of scintillator molecules or organic scintillator molecules encapsulated with an inclusion compound, and aromatic rings formed by a coupling agent, which are fixed inside or on the surface of silica nanoparticles by the sol-gel method. Or silica nanoparticles containing organic scintillator molecules are immobilized on the surface of the particles or fibers.

The radiation test paper according to the seventh aspect of the present invention is a radiation test paper including a radiation detection powder containing a scintillator that is excited by radiation and emits light, and the radiation detection powder is encapsulated with an inclusion compound. A composite of organic scintillator molecules and silica nanoparticles in which an organic scintillator molecule or an aromatic ring formed by a coupling agent is fixed inside or on the surface of silica nanoparticles by the sol-gel method. Radiation detection powder and cellulose nanofibers. Aggregates are collected and made into a sheet.

The radiation test paper according to the eighth embodiment of the present invention is a radiation test paper including a radiation detection powder containing a scintillator that is excited by radiation and emits light, and the radiation detection powder is silica nanoparticles containing an organic scintillator molecule. Is immobilized on the surface of particles or fibers, and the radiation detection powder and the fibers containing the binder fibers are wet-paper-made to form a sheet.

The method for producing a radiation test paper according to a ninth aspect of the present invention is a method for manufacturing a radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light, and is a paper made into a sheet. A preparatory step for preparing a sheet-like base material made of wood, a coating step of applying a dispersion liquid in which radiation detection powder is dispersed in a solvent as a coating liquid to the surface of the sheet-like base material, and a coating step of applying the radiation detection powder to the sheet-like base material It includes a drying step of removing all or part of the solvent from the coating solution to form a coating layer.

The method for producing a radiation test paper according to a tenth aspect of the present invention is a sol-gel method in which a radiation detection powder is subjected to an organic scintillator molecule or an organic scintillator molecule encapsulated with an inclusion compound and an aromatic ring using a coupling agent. A composite of organic scintillator molecules and silica nanoparticles, which is fixed to the inside or the surface of the silica nanoparticles, is formed, and the radiation detection powder is dispersed in an organic solvent to prepare a coating liquid.

In the method for producing a radiation test paper according to the eleventh embodiment of the present invention, the radiation detection powder is obtained by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of particles or fibers, and the radiation detection powder is used as cellulose. It is used as a coating liquid by dispersing it in a dispersion liquid containing nanofibers.

The method for producing a radiation test paper according to a twelfth aspect of the present invention is a method for producing a radiation test paper including a radiation detection powder containing a scintillator that is excited by radiation and emits light, and is encapsulated with an inclusion compound. Prepare a radiation detection powder which is a composite of organic scintillator molecules and silica nanoparticles in which the organic scintillator molecules or the aromatic ring of the coupling agent are fixed inside or on the surface of the silica nanoparticles by the sol-gel method. A preparatory step, a first dispersion step of dispersing the radiation detection powder in an organic solvent to obtain a first dispersion, a second dispersion step of dispersing cellulose nanofibers in water to obtain a second dispersion, and a first dispersion. A coagulation step of mixing the liquid and the second dispersion to agglomerate the radiation detection powder and the cellulose nanofibers, and filtering the mixed liquid containing the agglomerates of the radiation detection powder and the cellulose nanofibers into a sheet. It includes a paper-making process for making paper.

The method for producing a radiation test paper according to the thirteenth aspect of the present invention is a method for producing a radiation test paper including a radiation detection powder containing a scintillator that is excited by radiation and emits light, and is a silica nano that contains an organic scintillator molecule. A preparatory step of preparing a radiation detection powder obtained by immobilizing particles on the surface of particles or fibers, and suspending the radiation detection powder and fibers containing binder fibers in a dispersion liquid to prepare a papermaking slurry, and using this papermaking slurry as a wet type. It includes a paper making process of making a sheet of radiation inspection paper.

According to the radiation detection powder of the present invention and the method for producing the same, it is possible to realize a feature that the ratio of organic scintillator molecules to the entire radiation detection powder can be increased to increase the detection sensitivity of radiation per unit amount. In addition, the time required for forming silica nanoparticles containing organic scintillator molecules can be significantly shortened, which enables mass production at low cost.

According to the radiation inspection paper of the present invention and the manufacturing method thereof, by making the radiation detection material made of paper, there is a feature that the inspection work can be simplified while mass-producing at low cost. In addition, unlike a liquid scintillator, it is possible to solve complicated problems associated with the treatment and storage of radioactive liquid waste, and it is possible to realize an excellent feature that water can be measured.

It is a schematic cross-sectional view which shows the radiation inspection paper which concerns on one Embodiment of this invention. It is a schematic sectional view and the enlarged sectional view of the main part which show the radiation inspection paper which concerns on other embodiment of this invention. It is a schematic cross-sectional view of the radiation inspection paper which concerns on other embodiment of this invention. It is a perspective view which shows the manufacturing process of the radiation inspection paper which concerns on one Embodiment of this invention. It is a schematic process diagram which shows the manufacturing process of the radiation inspection paper which concerns on other embodiment of this invention. It is an enlarged sectional view of the radiation inspection paper which concerns on other embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments shown below exemplify a radiation detection powder and a method for producing the same, and a radiation test paper provided with the radiation detection powder and a method for producing the same, for embodying the technical idea of the present invention. The present invention does not specify the radiation detection powder and its production method, and the radiation test paper provided with the radiation detection powder and its production method to the following and the method. In addition, the present specification does not specify the members shown in the claims as the members of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention to the specific description, and are merely explanatory examples. It's just that. The size and positional relationship of the members shown in each drawing may be exaggerated to clarify the explanation. Further, in the following description, members of the same or the same quality are shown with the same name and reference numeral, and detailed description thereof will be omitted as appropriate. Further, each element constituting the present invention may be configured such that a plurality of elements are composed of the same member and the plurality of elements are combined with one member, or conversely, the function of one member is performed by the plurality of members. It can also be shared and realized.

[Embodiment 1]
(Radiation detection powder)
The radiation detection powder according to an embodiment of the present invention is a radiation detection powder containing a scintillator that is excited by radiation and emits light. The scintillator is a composite of an organic scintillator molecule and silica nanoparticles, and this composite is The organic scintillator molecule or the organic scintillator molecule encapsulated with the inclusion compound and the aromatic ring of the coupling agent are fixed to the inside or the surface of the silica nanoparticles by the sol-gel method.

This radiation detection powder is prepared by a first mixing step in which an organic scintillator molecule and an inclusion compound are added to an organic solvent and heated to dissolve the organic scintillator molecule or the organic scintillator molecule encapsulated by the inclusion compound in the organic solvent. A silicic acid source and a coupling agent are added to the first mixed solution obtained in the first mixing step, and the mixture is heated and stirred. The organic scintillator molecules are fixed to the inside or the surface by the sol-gel method, and the inside or the inside or the surface is fixed by the coupling agent. The second mixing step of forming silica nanoparticles having an aromatic ring fixed on the surface to form a complex of organic scintillator molecules and silica nanoparticles, and the second mixing solution obtained in the second mixing step are heated and dried. It is manufactured by a heating-drying process to obtain radiation detection powder.

The organic scintillator molecules constituting the radiation detection powder are scintillator particles having a fluorescent property of being excited by radiation and emitting light, and examples thereof include the following.

Benzoxazole derivatives: 1,1'-biphenyl, 4-yl-6-phenyl-benzoxazole TLA, 2-phenylbenzoxazole, 2- (4'-methylphenyl) -benzoxazole, 2- (4'-methylphenyl) )-5-Methylbenzoxazole, 2- (4'-methylphenyl) -5-t-butylbenzoxazole, 2- (4'-t-butylphenyl) -benzoxazole, 2-phenyl-5-t-butyl -Benzoxazole, 2- (4'-t-butylphenyl) -5-t-butyl benzoxazole, 2- (4'-biphenylyl) -benzoxazole, 2- (4'-biphenylyl) -5-t-butyl Benzoxazole, 2- (4'-biphenylyl) -6-phenyl-benzoxazole (PBBO), etc. Oxazole derivatives: 2-p-biphenylyl-5-phenyloxazole (BPO), 2,2'-p-phenylenebis (5) -Phenyloxazole) (POPOB), 2,5-diphenyloxazole (DPO), 1,4-bis [2- (5-phenyloxazolyl)] benzene (POPOP), 1,4-bis-2- (4) -Methyl-5-phenyloxazolyl) benzene (DMPOPOP), etc. Oxadiazole derivatives: 2,5-diphenyloxaziazole (PPD), 2,5-diphenyl-1,3,4-oxadiazole, 2- (4'-t-Butylphenyl) -5-phenyl-1,3,4-oxadiazole, 2,5-di- (4'-t-butylphenyl) -1,3,4-oxadiazole, 2-Phenyl-5- (4 ″ -biphenylyl) -1,3,4-oxadiazole (PBD), 2- (4'-t-butylphenyl) -5- (4 ″ -biphenylyl) -1 , 3,4-Oxaziazole (butyl-PBD), etc. Terphenyl derivatives: 4,4''-di-tert-amyl-p-terphenyl (DAT), etc. Multinuclear aromatic compounds: 4,4'-bis ( 2,5-Dimethylstyryl) diphenyl (BDB), p-terphenyl scintillator, etc. Pyrazoline derivatives: 1-phenyl-3-mesityl-2-pyrazolin (PMP), 1,5-diphenyl-3- (4-phenyl-1) , 3-Butadienyl) -2-pyrazoline (DBP), 1,5-diphenyl-β-styrylpyrazoline (DSP), etc. Phosphoramide derivatives: anilinovis (1-aziridinyl) phosphine oxide (PDP), etc. Derivatives: 2,5-bis-benzoxazolyl (2') -thiophene, 2,5-bis- [5'-methylbenzoxazolyl (2')]-thiophene, 2,5-bis- [ 4', 5'-dimethylbenzoxazolyl (2')]-thiophene, 2,5-bis- [4', 5'-dimethylbenzoxazolyl (2')]-3,4-dimethylthiophene, 2,5-bis- [5'-isopropylbenzoxazolyl (2')]-3,4-dimethylthiophene, 2-benzoxazolyl (2') -5- [7'-sec-butyl-benzo Oxazolyl (2')]-thiophene, 2-benzoxazolyl (2')-5-[5'-t-butyl-benzoxazolyl (2')]-thiophene, 2,5-bis- [5'-t-Butylbenzoxazolyl (2')]-thiophene (BBOT) and the like.

The organic scintillator molecule used in the radiation detection powder may be one kind alone, but preferably a combination of two or more kinds. The organic scintillator molecules can be used in appropriate combinations as long as radiation can be detected. As such a combination, for example, a combination of a first solute and a second solute used in a liquid scintillator can be adopted. Examples of the first solute include p-terphenyl, 2,5-diphenyloxazole (DPO), 2- (4'-t-butylphenyl) -5- (4 ″ -biphenylyl) -1,3,4-. Oxadiazole (butyl-PBD) and the like can be mentioned. Examples of the second solute include 1,4-bis [2- (5-phenyloxazolyl)] benzene (POPOP) and 1,4-bis-2- (4-methyl-5-phenyloxazolyl) benzene. (DMPOPOP) and the like. As a preferable combination, a combination of DPO and POPOP can be adopted.

The complex of the organic scintillator molecules is not particularly limited as long as it is a complex of an organic scintillator molecule and silica nanoparticles, and is preferably a complex of a plurality of types of organic scintillator molecules and silica nanoparticles. The silica nanoparticles are bonded together with the organic scintillator molecules attached on the surface of the particles or with the organic scintillator molecules contained inside the particles to form a complex. The organic scintillator molecule is preferably encapsulated inside the silica nanoparticles.

The silica nanoparticles can have a particle size obtained by a conventional method for producing silica nanoparticles. The average particle size of the silica nanoparticles can be, for example, 10 to 500 nm, preferably 30 to 400 nm, more preferably 70 to 300 nm, and even more preferably about 100 to 200 nm.

Complexes of organic scintillator molecules and silica nanoparticles can be obtained according to known methods. For example, silica nanoparticles containing organic scintillator molecules can be obtained by forming silica nanoparticles in the presence of organic scintillator molecules. For example, silica nanoparticles containing organic scintillator molecules can be obtained by a sol-gel method in which water, a silicic acid source, and a catalyst are added after dissolving the organic scintillator molecules in an organic solvent (lower alcohol).

Examples of the organic solvent for dissolving the organic scintillator molecule include ethanol and the like. The compounding ratio of the organic scintillator molecule and the organic solvent (organic scintillator molecule weight: organic solvent weight) is not particularly limited as long as the organic scintillator molecule can be dissolved in the organic solvent. These compounding ratios can be, for example, 1: 10 to 90, preferably about 1:30 to 70. The organic scintillator molecule can be easily dissolved in ethanol by inclusion in cyclodextrin.

The other organic solvent that can be used is not particularly limited as long as it is a lower alcohol that can be used for forming silica nanoparticles. Examples of the lower alcohol include methanol, ethanol, n-propanol, 2-propanol and the like, and ethanol is preferable. In this embodiment, ethanol is used as the organic solvent for dissolving the above-mentioned organic scintillator molecules.

In the present embodiment, the clathrate compound is added to the organic solvent (lower alcohol) in the first mixing step of dissolving the organic scintillator molecule in the organic solvent. As the clathrate compound, for example, cyclodextrin, which is a kind of cyclic oligosaccharide, specifically, β-cyclodextrine, sulfated, sodium salt can be used. The pores inside the β-cyclodextrin sulfate Na salt have a pore size of 0.6 to 0.8 nm, and the inside of the pores easily enclose hydrophobic molecules, so water-insoluble substances are encapsulated inside. It has the characteristic of being easy to touch. By clathrate the organic scintillator molecule with the clathrate compound in this way, the organic scintillator molecule can be rapidly dissolved in the organic solvent. Further, since sulfated β-cyclodextrin has the same structure as Si (O−) _{4 of} TEOS, which is a silicic acid source described later, like −SO ₃ O−, silica nanoparticles are formed during silica formation. It becomes easy to be fixed to the inside or the surface of the. In the first mixing step, the clathrate compound is added so as to be 1 wt% or more, preferably 1.6 wt% or more by weight.

Further, in order to form silica nanoparticles in which organic scintillator molecules are fixed on the surface or inside, a silicic acid source which is a silica source is used in the second mixing step with respect to the first mixed solution obtained in the first mixing step. In addition to, add a coupling agent. That is, in the second mixing step, water, a silicic acid source, a coupling agent, and a catalyst are added to the first mixed solution and heated and stirred, and the organic scintillator molecules are fixed to the inside or the surface by the sol-gel method, and the cup is used. The ring agent forms silica nanoparticles having an aromatic ring fixed inside or on the surface, and forms a complex of organic scintillator molecules and silica nanoparticles.

The silicic acid source is not particularly limited as long as it is a silicic acid source that can be used for forming silica nanoparticles. Examples of the silicic acid source include tetraethyl orthosilicate (TEOS), tetramethyl orthosilicate (TMS), tetrapropyl orthosilicate (TPOS) and the like, and tetraethyl orthosilicate is preferably used. The blending amount of the silicic acid source can be, for example, about 1/500 to 1/5 of the lower alcohol.

As the coupling agent, for example, a silane coupling agent can be used, and specifically, p-styryltrimethoxysilane is used. The p-styryltrimethoxysilane, which is a silane coupling agent, has a functional group that binds to an organic material and an inorganic material in the molecule, and has a property of binding the organic material and the inorganic material. However, any coupling agent having an aromatic ring such as a benzene ring structure such as a styryl group or a phenyl group can be used. In the second mixing step, the coupling agent is added so that the molar ratio with respect to the organic scintillator molecule is 0.2 times or more, preferably 2 times or more.

The catalyst is not particularly limited as long as it can be used for forming silica nanoparticles. Examples of the catalyst include a base catalyst, an acid catalyst and the like, and a base catalyst is preferable. Examples of the base catalyst include ammonia and the like, and examples of the acid catalyst include hydrochloric acid, sulfuric acid, nitric acid, acetic acid and the like.

The ratio of the organic scintillator molecule to the total weight of the composite of the organic scintillator molecule is, for example, 5 to 80% by weight, preferably 15 to 70% by weight, more preferably 25 to 60% by weight, still more preferably 30 to 55% by weight. Can be.

[Example 1]
The radiation detection powder having the above structure is produced by the following steps.
(1) First mixing step In 40 mL of ethanol, about 4.6 g of DPO (2,5 Diphenyloxazole) and about 0.53 g of POPOP (1,4-Bis (5-phenyl-2-oxazolyl) benzene) as organic scintillator molecules. About 0.4 g of β-cyclodextrin sulfated Na salt as a clathrate compound is added, and the mixture is heated on a hot stirrer at about 80 ° C. for 30 minutes to dissolve the organic scintillator molecules in ethanol (first mixing). liquid).
(2) Second mixing step In an ethanol solution in which organic scintillator molecules are dissolved, 9 mL of TEOS (Tetraethylorthosilicate) is used as a silicic acid source, 10 mL of p-styryltrimethoxysilane as the first coupling agent, 100 mL of distilled water, and concentrated ammonia as a catalyst. Add 10 mL of water. At this time, p-styryltrimethoxysilane is prepared so as to be about twice the molar ratio to DPO, and β-cyclodextrin sulfated Na salt is prepared so as to be about 1.6 wt% by weight. Further, the amount of water added in the second mixing step is 100 mL with respect to 400 mL of ethanol in the first mixing step, that is, the volume ratio of ethanol: water is 4: 1.
The mixed solution prepared as described above is heated and stirred on a hot stirrer at about 80 ° C. for 2 hours to form silica nanoparticles containing organic scintillator molecules to form a complex of organic scintillator molecules and silica nanoparticles. (Second mixed solution).
(3) Heat-drying step About 14.5 g of white powder (radiation detection powder) is obtained by heating-drying a second mixed solution in which a complex of organic scintillator molecules and silica nanoparticles is formed in a solution on a hot stirrer. Obtained.

The radiation detection powder produced as described above had an organic scintillator molecule ratio of about 35 wt% with respect to the entire radiation detection powder. Further, the radiation detection powder was not dispersed in ethanol at room temperature, but was uniformly dispersed when heated to about 80 ° C., and was not uniformly dispersed in water. In addition, this radiation detection powder showed physical properties of swelling containing ethanol and solidifying at a low temperature (refrigerator). In particular, in the above production method, by using cyclodextrin in the first mixing step, silica nanoparticles can be easily dispersed in ethanol.

As described above, in the radiation detection powder according to the embodiment of the present invention, the ratio of the organic scintillator molecules to the entire radiation detection powder was set to about 35 wt%, which was significantly higher than the conventional one. Therefore, it is possible to realize a feature that the detection of radiation can be simplified while increasing the detection sensitivity of radiation per unit amount. Further, in the second mixing step, the time required to form the complex of the organic scintillator molecule and the silica nanoparticles was set to several hours, which could be significantly shortened as compared with the conventional production method. As a result, the time required for producing the radiation detection powder can be shortened, and mass production at low cost has become possible.

The radiation detection powder produced as described above can be used for various purposes as a radiation detection powder that emits light when excited by radiation. Further, in the present invention, as one of the above-mentioned use examples of the radiation detection powder, the radiation detection powder can be contained in a paper sheet to be used as a radiation inspection paper. Hereinafter, the radiation test paper provided with the radiation detection powder and the manufacturing method thereof will be described in detail.

[Embodiment 2]
A radiation inspection paper according to an embodiment of the present invention is shown in a schematic cross-sectional view of FIG. The radiation test paper 10 shown in FIG. 1 includes a sheet-shaped base material 1 made of paper made into a sheet, and a coating layer 2 containing a radiation detection powder coated on the surface of the sheet-shaped base material 1. ing. The radiation test paper 10 is a sheet-shaped base material 1 in which a preparatory step for preparing a paper-made sheet-shaped base material 1 made into a sheet-like paper and a dispersion liquid in which radiation detection powder is dispersed in a solvent are used as a coating liquid. It is produced by a coating step of applying to the surface and a drying step of removing all or a part of the solvent from the coating liquid applied to the sheet-like base material 1 to form the coating layer 2.

(Sheet-like base material 1)
The sheet-like base material 1 is made of paper, and is produced by wet-making paper from natural fibers or synthetic fibers. As the natural fiber, cellulosic fibers such as wood fiber, seed hair fiber, bast fiber, leaf vein fiber and the like can be used. On the other hand, as the synthetic fiber, for example, synthetic fibers such as polyamide-based, polyolefin-based, polyester-based, polyacrylonitrile-based, and polyvinyl alcohol-based can be preferably used. The fiber diameter of the fibers constituting the paper sheet base material 1 is, for example, 0.05 μm to 100 μm, preferably 0.1 μm to 80 μm, in consideration of the average diameter of the radiation detection powder contained therein. In particular, it is preferably 1 μm to 60 μm. As a result, the radiation detection powder can be effectively retained.

In the example of FIG. 1, for the sake of explanation, a radiation inspection paper having a two-layer structure in which the coating layer 2 is coated on one surface of the sheet-like base material 1 is shown, but the sheet-like base material 1 and the coating layer 2 Is not necessarily divided into clear layers, and it is sufficient if the coating layer 2 is formed on the surface of the sheet-like base material 1. That is, as will be described later, when the coating liquid is applied to the paper fibers constituting the sheet-like base material 1 to form the coating layer 2, as shown in the enlarged cross-sectional view of the main part of FIG. 2, the sheet-like group is formed. The mode is such that the coating layer 2 is formed on the surface of the fiber 6 of the material 1. In such an embodiment in which the coating layer 2 is microscopically formed on the surface of the fibers 6 constituting the sheet-like base material 1, the coating layer 2 formed on the surface of the sheet-like base material 1 in the present invention is also used. It shall be included in.

(Coating layer 2)
The coating layer 2 is formed by a coating liquid applied to the surface of the sheet-like base material 1. As the coating liquid, a dispersion liquid in which radiation detection powder is dispersed in a solvent is used. In the radiation test paper according to this embodiment, as the radiation detection powder, the organic scintillator molecule or the organic scintillator molecule, which is a composite of the above-mentioned organic scintillator molecule and silica nanoparticles and is encapsulated with an inclusion compound, is a sol-gel. A radiation detection powder composed of a complex in which an aromatic ring is fixed inside or on the surface of silica nanoparticles by a method and an aromatic ring is fixed inside or on the surface of silica nanoparticles by a coupling agent is used. Since this radiation detection powder does not disperse in water but disperses in an organic solvent, a coating liquid in which the radiation detection powder is dispersed in an organic solvent is used. As the organic solvent, a solvent such as ethanol can be used as a liquid in which the radiation detection powder can be easily dispersed. As described above, this radiation detection powder is uniformly dispersed in ethanol heated to about 80 ° C. Therefore, this radiation detection powder is used as a coating liquid in a state of being dispersed in heated ethanol. However, as the organic solvent, a polar solvent such as methanol can be used instead of ethanol.

The coating liquid in which the radiation detection powder is dispersed in a state of being heated to a high temperature is applied to the sheet-like base material 1 and then cooled to promote solidification, and all or part of the solvent is vaporized. By being converted and removed, the radiation detection powder, which is a solute, is solidified and fixed to the fibers of the sheet-like base material 1.

A bar coater 9 can be used for applying the coating liquid, for example, as shown in FIG. The bar coater 9 has a wire wound around the surface of the rod-shaped body, and the coating amount can be controlled by holding the coating liquid between the wires. Other coating methods include roll coaters, gravure coaters, knife coaters, blade coaters, rod coaters, air doctor coaters, curtain coaters, fountain coaters, kiss coaters, screen coaters, extrusion coaters, and the like. Furthermore, the coating liquid can also be applied by spraying or brushing.

Further, the amount of the coating liquid applied is 10 g or more, preferably 100 g to 400 g, per 1 m ² of the sheet-like substrate 1. The coating layer 2 may be provided over the entire surface of the sheet-like base material 1 as shown in FIG. 1, or may be partially provided in a specific region of the sheet-like base material 1 as shown in FIG. ..

The radiation inspection paper 10 shown in FIG. 1 can be used for radiation detection inspection by using the surface (upper surface in the drawing) on which the coating layer 2 is formed as the inspection surface 5. As shown in the figure, in the structure in which the coating layer 2 containing the radiation detection powder is provided on the surface of the sheet-like base material 1, the radiation detection powder can be concentratedly arranged on one side surface of the sheet-like base material 1, and thus this surface. Can be effectively detected by using the above as the inspection surface 5.

Further, as shown by the chain line in FIG. 1, the radiation inspection paper 10 may be provided with the surface layer 3 on the surface of the coating layer 2. The surface layer 3 can be, for example, a thin film made of thin paper. The radiation inspection paper 10 has a feature that the radiation detection powder adhered to the coating layer 2 can be effectively prevented from falling off from the surface of the coating layer 2.

Furthermore, as shown in FIG. 3, the radiation inspection paper can also have the release sheet 4 laminated on the surface of the coating layer 2. When the radiation inspection paper 30 is used, the surface of the coating layer 2 is coated with the release sheet 4 to protect the coating layer 2 with the release sheet 4 when not in use. By peeling the release sheet 4, the inspection surface 5 can be exposed and used. As such a release sheet 4, for example, a hydrophobic material, for example, a resin sheet such as PET, PP, PE, PMP, PTFE, PVDF, or a sheet obtained by coating a paper or film with silicone or fluorine can be preferably used. .. However, the radiation detection powder may be in a state where the coating layer is exposed without necessarily providing a surface layer or a release sheet on the surface of the coating layer.

[Example 2]
The radiation test paper having the above structure is manufactured by the following process.
(1) Preparation Step A paper sheet-like base material 1 made into a sheet is prepared. As the sheet-shaped base material 1 made of paper, for example, a paper sheet obtained by wet-papering cellulose fibers can be used. The sheet-like base material 1 can have a thickness of 50 μm and a basis weight of 30 g / m ² .
(2) Coating step A coating solution is prepared by dispersing the radiation detection powder in a solvent. Here, as the radiation detection powder, the radiation detection powder produced in Example 1 composed of a composite of an organic scintillator molecule and silica nanoparticles is used. Ethanol is used as the organic solvent for dispersing this radiation detection powder. Prepare 50 g of ethanol and stir at 200 rpm while heating at 75 ° C. To the heated ethanol, 0.5 g of radiation detection powder is added, and the mixture is further stirred at 200 rpm for 60 minutes while maintaining at 75 ° C. As a result, a coating liquid in which the radiation detection powder is uniformly dispersed with respect to ethanol can be obtained.
The above coating liquid is applied to the surface of the sheet-like base material 1. A predetermined amount of the coating liquid is applied to the surface of the sheet-like base material 1 by using, for example, the bar coater 9 shown in FIG. The coating amount of the coating liquid is, for example, 100 g / m ² .
(3) Drying Step The coating liquid applied to the sheet-shaped base material 1 is dried at 100 ° C. for 30 minutes to vaporize and remove all or part of the solvent of the coating liquid, and radiation detection which is a solute of the coating liquid is detected. The powder is solidified and fixed to the fibers of the sheet-like base material 1. As a result, the coating layer 2 is formed on the surface of the sheet-like base material 1.

[Embodiment 3]
Further, the radiological examination paper according to another embodiment of the present invention will be described in detail. In this radiation test paper, the radiation detection powder is a composite of the above-mentioned organic scintillator molecules and silica nanoparticles, and the radiation detection powder and the aggregates of cellulose nanofibers are aggregated and made into a sheet. In this radiological examination paper, organic scintillator molecules or organic scintillator molecules encapsulated with an inclusion compound are fixed to the inside or the surface of silica nanoparticles by the sol-gel method, and an aromatic ring is attached to the inside or the surface of the silica nanoparticles by a coupling agent. A preparatory step for preparing a radiation detection powder which is a composite of organic scintillator molecules and silica nanoparticles, a first dispersion step for dispersing the radiation detection powder in an organic solvent to obtain a first dispersion, and cellulose. A second dispersion step in which nanofibers are dispersed in water to obtain a second dispersion, a coagulation step in which the first dispersion and the second dispersion are mixed to aggregate the radiation detection powder and the cellulose nanofibers, and radiation. It is produced by a papermaking process in which a mixed solution containing agglomerates of detected powder and cellulose nanofibers is filtered and made into a sheet.

This radiation test paper is produced by a papermaking method using the radiation detection powder shown in the first embodiment described above. As described above, the radiation detection powder used here has an average particle size of a composite of organic scintillator molecules and silica nanoparticles having a nano size. Therefore, in a normal papermaking method, the composite passes through a mesh and is used as paper. I can't make it. In addition, since this ray detection powder does not disperse in water, this also makes it difficult to make paper by a usual method.

In order to solve this problem, in the method for producing a radiation test paper according to this embodiment, as shown in FIG. 5, the radiation detection powder is dispersed in an organic solvent to obtain a first dispersion liquid 11, and cellulose nano is formed. The fibers are dispersed in water to obtain a second dispersion liquid 12, and the respective dispersion liquids are mixed to aggregate the radiation detection powder and the cellulose nanofibers to form an aggregate 15, and the aggregate 15 is filtered. The paper is made into a sheet.

[Example 3]
The radiation test paper having the above structure is manufactured by the following process.
(1) Preparation Step As the radiation detection powder, the radiation detection powder prepared in the above-mentioned Example 1 and composed of a composite of an organic scintillator molecule and silica nanoparticles is prepared.
(2) First Dispersion Step In this step, the radiation detection powder is dispersed in an organic solvent to obtain the first dispersion liquid 11. Ethanol is used as the organic solvent for dispersing this radiation detection powder. Prepare 100 g of ethanol and stir at 200 rpm while heating at 75 ° C. To the heated ethanol, 0.50 g (50 parts by weight) of radiation detection powder is added, and the mixture is further stirred at 200 rpm for 60 minutes while maintaining at 75 ° C. As a result, the first dispersion liquid 11 in which the radiation detection powder is uniformly dispersed with respect to ethanol is prepared.
(3) Second Dispersion Step In this step, cellulose nanofibers are dispersed in water to obtain a second dispersion liquid 12. As the cellulose nanofibers, those having a fiber diameter of 3 nm to 200 nm are preferably used, and those having a fiber diameter of 50 nm to 100 nm are more preferably used. Here, fine fibrous cellulose (manufactured by Daicel Corporation) is used as the cellulose nanofibers. A predetermined amount of fine fibrous cellulose is suspended and dispersed in water as a dispersion liquid to prepare 50 parts by weight of a 0.5 wt% aqueous solution of fine fibrous cellulose.
(4) Aggregation Step The first dispersion liquid 11 and the second dispersion liquid 12 are mixed to aggregate the radiation detection powder and cellulose nanofibers (fine fibrous cellulose) (for 2 minutes). In this way, after each good solvent (radiation detection powder: ethanol, cellulose nanofiber: water) is dispersed, each poor solvent (radiation detection powder: water, cellulose nanofiber: ethanol) is mixed to generate radiation. An aggregate 15 of the detection powder and cellulose nanofibers can be obtained. Since the radiation detection powder dispersed in the organic solvent and the cellulose nanofibers dispersed in water are both nano-sized, they do not yield as they are, but they can be aggregated and filtered to make paper. become.
(5) Papermaking process The mixed solution 13 in which the radiation detection powder and the cellulose nanofibers are agglomerated is filtered to make a sheet. In this step, a mixed solution containing the radiation detection powder and the aggregate 15 of cellulose nanofibers is filtered using qualitative filter paper No. 1 (manufactured by Advantech Toyo Co., Ltd.). However, for the filtration of the mixed solution 13, suction filtration can also be performed using a Nutche filter. The filtered aggregate 15 is peeled from the filter paper and dried at 100 ° C. for 10 minutes to obtain a radiation test paper. Here, the obtained radiological examination paper had a thickness of 0.23 mm and a basis weight of 106 g / m ² .

Further, in the present invention, as the radiation detection powder used for the radiation test paper, the organic scintillator molecule or the organic scintillator molecule encapsulated with the above-mentioned inclusion compound is fixed to the inside or the surface of the silica nanoparticles by the sol-gel method. Instead of radiation detection powder composed of a complex in which an aromatic ring is immobilized inside or on the surface of silica nanoparticles by a coupling agent, silica nanoparticles containing organic scintillator molecules are immobilized on the surface of particles or fibers. Radiation detection powder can be used. In this radiation detection powder, inorganic particles such as silicate particles can be used as particles for immobilizing silica nanoparticles containing organic scintillator molecules on the surface, and silica nanoparticles containing organic scintillator molecules can be used on the surface. As the fibers to be immobilized on the surface, supporting fibers having a predetermined fiber diameter can be used.

A radiation detection powder (hereinafter, also referred to as scintillator silica siliceous stone powder) that uses siliceous particles as particles for immobilizing silica nanoparticles includes siliceous particles and a scintillator immobilized on the surface of the siliceous particles, and the scintillator is provided. Is a silica nanoparticle containing an organic scintillator molecule. The radiation detection powder (cintilator silica silica stone powder) can have an average particle size of silica stone particles of 0.5 to 50 μm, preferably 1 to 30 μm, and more preferably 1.5 to 20 μm, and the average of silica nanoparticles. The particle size can be 30 to 400 nm. The radiation detection powder can also immobilize the scintillator on the silica stone particles via an adhesive.

This radiation detection powder (scintillator silica silica stone powder) is produced as follows.
(1) First Mixing Step In 240 mL of a dimethyl sulfoxide (DMSO) solution which is an organic solvent, about 0.53 g of benzoic acid, about 4.6 g of DPO (2,5 Diphenyloxazole) and POPOP (as organic scintillator molecules) are added. After adding about 5.1 g of 1,4-Bis (5-phenyl-2-oxazolyl) benzene), add 160 mL of ethanol. Heat on a hot stirrer to about 80 ° C. and stir until the organic scintillator molecules dissolve and become a clear solution.
(2) Second Mixing Step Next, about 1.2 g of silica stone powder (6.78 μm) is added to 25 mL of a 0.5 wt% water glass solution in advance with respect to the mixed solution in which the organic scintillator molecule is dissolved, and the temperature is about 80 ° C. Add 75 mL of distilled water, 10 mL of TEOS (Tetraethylorthosilicate) as a silicic acid source, and 10 mL of 28 wt% concentrated ammonia water as a catalyst to the solution heated and stirred in. At this time, 100 mL of water is added to 400 mL of the ethanol solution containing DMSO, in other words, the ratio of the ethanol solution to the added aqueous solution is 4: 1.
The mixed solution prepared as described above is heated to about 80 ° C. on a hot stirrer and stirred for about 2 days to form silica nanoparticles containing organic scintillator molecules, and the organic scintillator is formed on the surface of the silica stone powder. Molecule-containing silica nanoparticles were bound.
(3) Heat-drying step The above mixed solution was heated and dried on a hot stirrer to obtain a powder.
(4) Filtration and washing step The powder obtained in the heating and drying step was washed and filtered with a filter having a pore size of 0.1 μm using 400 to 600 mL of distilled water, and the operation of removing the water-soluble sulfur compound was repeated. ..
After drying with a desiccator, it was heated and dried with a hot stirrer to obtain about 31.4 g of white powder (scintillator silica silica stone powder).

Further, the radiation detection powder for immobilizing silica nanoparticles on fibers (hereinafter, also referred to as scintillator silica fiber powder) includes a supported fiber having a predetermined fiber diameter and a scintillator immobilized on the surface of the supported fiber. , This scintillator is a silica nanoparticle containing an organic scintillator molecule. As the supporting fiber, the radiation detection powder (cintilator silica fiber powder) can use, for example, inorganic fibers such as glass fiber and carbon fiber, and organic fiber such as synthetic fiber and natural fiber. The fiber diameter of the supported fiber can be 3 nm to 200 nm, preferably 3 nm to 40 nm. In addition, this radiation detection powder can also immobilize silica nanoparticles containing an organic scintillator on the surface of the fiber via a binder fiber. As such a binder fiber, for example, micro-order cellulose nanofibers and the like can be used. This radiation detection powder (scintillator silica fiber powder) is produced in the same manner as in the above-mentioned production step except that the supporting fiber is added in place of the silica stone powder in the above-mentioned second mixing step.
Further, supported fibers having a fiber diameter of 0.1 μm to 100 μm, preferably 10 μm to 50 μm can be used for production in the same manner as in the above-mentioned production step.

[Embodiment 4]
The radiation test paper produced by using the radiation detection powder (scintillator silica silica stone powder) produced as described above will be described in detail below as another embodiment of the present invention. Similar to the radiation test paper of the second embodiment described above, this radiation test paper contains a sheet-like base material made of paper made into a sheet and a radiation detection powder applied to the surface of the sheet-like base material. It has a coating layer to be used. This radiation test paper is in the form of a sheet, with a preparatory step of preparing a sheet-like base material made of paper made into a sheet, and a dispersion liquid in which radiation detection powder (scintillator silica silica stone powder) is dispersed in a solvent as a coating liquid. It is produced by a coating step of applying to the surface of a base material and a drying step of removing all or a part of a solvent from a coating liquid applied to a sheet-like base material to form a coating layer.

Furthermore, the radiation test paper, which is a scintillator silica silica stone powder in which silica nanoparticles containing organic scintillator molecules are immobilized on the surface of the scintillator particles, is used as a coating liquid for radiation detection in a dispersion containing cellulose nanofibers. A dispersion of powder (scintillator silica silica stone powder) is used. As this coating liquid, a dispersion liquid containing cellulose nanofibers at a predetermined concentration is used in which a predetermined amount of radiation detection powder (scintillator silica silica stone powder) is dispersed. The concentration of the dispersion liquid containing the cellulose nanofibers can be 0.01 wt% to 5 wt%, and the mass ratio of the dispersion liquid containing the cellulose nanofibers to the radiation detection powder (scintillator silica silica stone powder) is 10: It can be 90 to 3:97. The cellulose nanofibers are physically opened before being mixed with the radiation detection powder (scintillator silica silica stone powder). For example, wood pulp or the like can be mixed with a solvent such as water and pulverized by a grinder or the like.

[Example 4]
The radiation test paper having the above structure is manufactured by the following process.
(1) Preparation step A paper sheet-like base material that has been made into a sheet is prepared. As the sheet-like base material made of paper, for example, a paper sheet obtained by wet-papering polyester fibers can be used. The sheet-like base material can have a thickness of 130 μm and a basis weight of 100 g / m ² .
(2) Coating step A coating solution is prepared by dispersing the radiation detection powder in a solvent. Here, as the radiation detection powder, scintillator silica silica stone powder in which silica nanoparticles containing organic scintillator molecules are immobilized on the surface of silica stone particles is used. A 2 wt% aqueous solution of cellulose nanofibers is used as a dispersion liquid for dispersing the radiation detection powder. 95 parts by weight of radiation detection powder (scintillator silica silica stone powder) is added to 5 parts by weight of the aqueous solution of the cellulose nanofibers to prepare a coating liquid. As a result, a coating liquid in which the radiation detection powder is uniformly dispersed with respect to the cellulose nanofibers can be obtained.
The above coating liquid is applied to the surface of the sheet-like base material. A predetermined amount of the coating liquid is applied to the surface of the sheet-like base material 1 by using, for example, the bar coater 9 shown in FIG. The coating amount of the coating liquid is, for example, 309 g / m ² .
(3) Drying step The coating liquid applied to the sheet-shaped substrate is dried at 100 ° C. for 30 minutes to vaporize and remove all or part of the solvent of the coating liquid, and the radiation detection powder which is the solute of the coating liquid. (Scintillator silica silica stone powder) is solidified and fixed to the fibers of the sheet-like base material. As a result, a coating layer is formed on the surface of the sheet-like base material.

[Embodiment 5]
Further, another embodiment of the radiation test paper produced by using the radiation detection powder (scintillator silica silica stone powder) is shown in FIG. The radiation test paper 40 is formed by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of the silica stone particles as the radiation detection powder, and wet-making the radiation detection powder and the fibers containing the binder fibers into a sheet. It is formed in. This radiation test paper includes a preparatory step for preparing a radiation detection powder (scintillator silica silica stone powder 7) obtained by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of the silica stone particles, and a radiation detection powder and a binder fiber. A radiation inspection paper is produced by a papermaking process in which the fibers 6 are suspended in a dispersion liquid to obtain a papermaking slurry, and the papermaking slurry is wet-made into a sheet-shaped radiation inspection paper.

(Slurry for papermaking)
The radiation test paper is made by wet-making a papermaking slurry prepared by suspending a radiation detection powder (cintilator silica silica stone powder) and fibers containing binder fibers in a dispersion liquid. For example, water can be used as the dispersion liquid for suspending the radiation detection powder and the fibers containing the binder fibers.

As the binder fiber mixed in the papermaking slurry, natural cellulose fiber, polyolefin fiber, polyacrylonitrile fiber, and aramid fiber can be used. In particular, pulp-shaped fibers are most suitable. Further, resin fibers such as PET can be added to the binder fibers in addition to these fibers.

Furthermore, the papermaking slurry can also contain fibers other than binder fibers. As the fibers contained in the papermaking slurry, for example, the same fibers as those used for papermaking of the sheet-like base material described above, natural fibers, recycled fibers, synthetic fibers, inorganic fibers and the like can be appropriately used.

Further, a coagulant or a coagulant can be added to the papermaking slurry as a fixing agent. Specifically, fixing agents such as aluminum sulfate, alum, polydialyldimethylammonium, polyethyleneimine, cationized starch, colloidal silica, colloidal aluminum, bentonite, and polyphenol can be used. Alternatively, starch, polyacrylamide, polyvinyl alcohol and the like can be used as the dry paper strength agent, and polyethyleneimine, melamine formaldehyde, urea formaldehyde, polyamide epichlorohydrin, polyvinylamine and the like can be used as the wet paper strength agent.

[Example 5]
The radiation test paper having the above structure is manufactured by the following process.
(1) Preparation Step As a radiation detection powder, a scintillator silica silica stone powder in which silica nanoparticles containing organic scintillator molecules are immobilized on the surface of the silica stone particles is prepared.
(2) Papermaking process Radiation detection powder (scintillator silica silica stone powder) and fibers containing binder fibers are suspended in a dispersion to prepare a papermaking slurry. The papermaking slurry is prepared as follows.
Add 10 parts by weight of polyolefin synthetic pulp (manufactured by Mitsui Chemicals, Inc.) to 1 L of water and stir 300 times. Further, 20 parts by mass of microglass fiber (manufactured by H & V) and 70 parts by mass of radiation test paper (scintillator silica silica stone powder) are added and stirred 100 times to uniformly disperse the fiber and the radiation detection powder.
The above slurry is diluted to 1.5 L and then stirred at 300 rpm. As a binder fiber, 1% of polyamide epichlorohydrin resin (manufactured by Seiko PMC) is added, and the mixture is stirred for 1 minute. Further, 1% of polyacrylamide resin (manufactured by Arakawa Chemical Industry Co., Ltd.) is added as a binder fiber, and the mixture is stirred for 1 minute. Further, 0.2% of aluminum sulfate is added, and the mixture is stirred for 1 minute.
The papermaking slurry prepared as described above is made into a sheet by making paper with a 250 mm square square sheet machine.
The paper-made sheet is dried at 100 ° C. for 20 minutes to obtain a radiation test paper. Here, the obtained radiological examination paper had a thickness of 0.35 mm and a basis weight of 160.3 g / m ² .

The radiation inspection paper of the present invention produced as described above is cut into a predetermined shape and used for a radiation wiping inspection or the like. In the radiation inspection paper to be wiped and inspected, the surface of the portion to be inspected is wiped with the inspection surface of the radiation inspection paper, and the light emission from the scintillator of the radiation inspection paper is detected by the scintillation counter to measure the radiation count rate. The radiation test paper emits light when the scintillator contained in the radiation detection powder is excited by radiation. The scintillation counter amplifies the light emission of the set radiation test paper with a photomultiplier tube and converts it into a current value, and the radiation count rate is measured from the detected value.

The performance inspection of the radiation test papers of Examples 2 to 5 produced as described above was performed as follows.
The radiation test paper manufactured in Examples 2 to 5 is cut into a circular shape having a diameter of 1.4 cm (area: about 1.5 cm ² ) to make a test piece, and a wiping inspection by the Sumiya method is performed to count the radiation. The rate was measured. For the test pieces of Examples 2 to 5, the portion to be inspected was wiped off with the inspection surface of each test piece, and then set on a scintillation counter to measure the radiation count rate.
Further, as a comparative example, the same wiping inspection was performed using a Sumiya filter paper having a diameter of 2.5 cm (area: about 4.9 cm ² ), and the radiation count rate was measured. For the Sumiya filter paper of the comparative example, after wiping the portion to be inspected, 5 mL of a liquid scintillator was added and set on a scintillation counter to measure the radiation count rate.
The wiping inspection was carried out three times for each of Examples 2 to 5 and Comparative Example, and the average value was calculated. Further, each measured value was corrected according to the area of the Sumiya filter paper after obtaining a substantial counting rate after subtracting the background, and the corrected counting rate was compared. The results of the above wiping inspection are as follows. Example 2 was corrected by the wiping efficiency with respect to Examples 3 to 5.

In the above wiping inspection, it was confirmed that the area-corrected count rate of the radiation test papers of Examples 3 to 5 was superior to the count rate of the Sumiya filter paper as a comparative example.
On the other hand, in Example 2, since the counting rate per coating amount exceeds 1, it is shown that increasing the coating amount of the inspection paper may exceed the comparative example.
Further, in the radiation inspection papers of Examples 2 to 5, after the portion to be inspected is wiped off, the radiation count rate can be measured by setting it on the scintillation counter as it is. Since secondary work such as adding a liquid scintillator can be omitted, the labor and time required for inspection can be shortened, and the cost can be reduced.

The radiation detection powder and the radiation test paper of the present invention can be conveniently used in the field of radiation inspection because they can be easily used while increasing the radiation detection sensitivity.

10, 20, 30, 40 ... Radiation test paper 1 ... Sheet-like base material 2 ... Coating layer 3 ... Surface layer 4 ... Release sheet 5 ... Inspection surface 6 ... Fiber 7 ... Scintillator silica silica stone powder 9 ... Bar coater 11 ... First dispersion Liquid 12 ... Second dispersion 13 ... Mixed liquid 15 ... Aggregates

Claims (13)

A radiation detection powder containing a scintillator that is excited by radiation and emits light.
The scintillator is a complex of organic scintillator molecules and silica nanoparticles.
The complex is characterized in that the organic scintillator molecule or the organic scintillator molecule encapsulated with the clathrate compound and the aromatic ring of the coupling agent are fixed to the inside or the surface of the silica nanoparticles by the sol-gel method. Radiation detection powder. The radiation detection powder according to claim 1, wherein the complex contains two or more types of organic scintillator molecules. The radiation detection powder according to claim 1 or 2, wherein the clathrate compound is a cyclic oligosaccharide.
A radiation detection powder in which the coupling agent is a silane coupling agent. A method for producing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
A first mixing step of adding an organic scintillator molecule and a clathrate compound to an organic solvent and heating to dissolve the organic scintillator molecule or the organic scintillator molecule encapsulated in the clathrate compound in the organic solvent.
A silicic acid source and a coupling agent are added to the first mixed solution obtained in the first mixing step, and the mixture is heated and stirred. The organic scintillator molecules are fixed to the inside or the surface by a sol-gel method, and the coupling agent. A second mixing step of forming silica nanoparticles in which the aromatic ring is fixed inside or on the surface to form a complex of the organic scintillator molecule and the silica nanoparticles.
A heating and drying step of heating and drying the second mixed solution obtained in the second mixing step to obtain a radiation detection powder, and a heating and drying step.
A method for producing a radiation detection powder containing. The method for producing a ray detection powder according to claim 4.
The clathrate compound is a cyclic oligosaccharide.
The coupling agent is a silane coupling agent.
A method for producing a radiation detection powder in which the silicic acid source is any one of tetraethyl orthosilicate, tetramethyl orthosilicate, and tetrapropyl orthosilicate. A radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
A sheet-like base material made of paper that has been made into a sheet,
A coating layer containing the radiation detection powder coated on the surface of the sheet-like substrate, and
With
The radiation detection powder
A composite of the organic scintillator molecule and the silica nanoparticles, wherein the organic scintillator molecule or the organic scintillator molecule encapsulated with the clathrate compound and the aromatic ring of the coupling agent are fixed to the inside or the surface of the silica nanoparticles by the sol-gel method. Body or
A radiological examination paper in which silica nanoparticles containing an organic scintillator molecule are immobilized on the surface of particles or fibers. A radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
The organic scintillator molecule in which the radiation detection powder is encapsulated with an inclusion compound or an organic scintillator molecule and an aromatic ring formed by a coupling agent are fixed to the inside or the surface of silica nanoparticles by a sol-gel method. And the composite of the silica nanoparticles
A radiation test paper made by assembling the radiation detection powder and the aggregates of cellulose nanofibers into a sheet. A radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
The radiation detection powder is obtained by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of particles or fibers.
Radiation test paper formed into a sheet by wet papermaking of the radiation detection powder and fibers containing binder fibers. A method for producing a radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
The preparatory process for preparing a sheet-like base material made of paper that has been made into a sheet,
A coating step of applying the dispersion liquid obtained by dispersing the radiation detection powder in a solvent to the surface of the sheet-like base material as a coating liquid, and
A drying step of removing all or a part of the solvent from the coating liquid applied to the sheet-like substrate to form a coating layer, and
Method of manufacturing radiological examination paper including. The method for producing a radiological examination paper according to claim 9.
The organic scintillator molecule in which the radiation detection powder is encapsulated with an inclusion compound or an organic scintillator molecule and an aromatic ring formed by a coupling agent are fixed to the inside or the surface of silica nanoparticles by a sol-gel method. And the composite of the silica nanoparticles
A method for producing a radiation test paper, wherein the coating liquid is a radiation detection powder dispersed in an organic solvent. The method for producing a radiological examination paper according to claim 9.
The radiation detection powder is obtained by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of particles or fibers.
A method for producing a radiation test paper, wherein the coating liquid is a dispersion liquid containing cellulose nanofibers in which the radiation detection powder is dispersed. A method for producing a radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
A composite of the organic scintillator molecule and the silica nanoparticles, wherein the organic scintillator molecule or the organic scintillator molecule encapsulated with the inclusion compound and the aromatic ring of the coupling agent are fixed to the inside or the surface of the silica nanoparticles by the sol-gel method. The preparatory step for preparing the radiation detection powder, which is the body, and
A first dispersion step of dispersing the radiation detection powder in an organic solvent to obtain a first dispersion.
A second dispersion step in which cellulose nanofibers are dispersed in water to form a second dispersion.
A coagulation step of mixing the first dispersion liquid and the second dispersion liquid to coagulate the radiation detection powder and the cellulose nanofibers.
A papermaking process in which a mixed solution containing the radiation detection powder and the aggregate in which the cellulose nanofibers are aggregated is filtered and made into a sheet.
Method of manufacturing radiological examination paper including. A method for producing a radiation test paper containing a radiation detection powder containing a scintillator that is excited by radiation and emits light.
A preparatory step for preparing the radiation detection powder obtained by immobilizing silica nanoparticles containing organic scintillator molecules on the surface of particles or fibers, and
A papermaking process in which fibers containing the radiation detection powder and binder fibers are suspended in a dispersion liquid to form a papermaking slurry, and the papermaking slurry is wet-made into a sheet-shaped radiation inspection paper.
Method of manufacturing radiological examination paper including.