JP2973308B2 - Radiation-sensitive substance and radiation detection method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation-sensitive substance which can be used even for low-level radiation, for example, for the purpose of visually ascertaining various levels of radiation dose accurately, and radiation detection using the same. It is about the method.

[0002]

2. Description of the Related Art Nuclear power plants and radiation (radioactive elements)
In medical and research facilities that handle radiation, etc., it is necessary to reduce radiation exposure to the human body by controlling radiation exposure.In facilities that use radiation irradiation for sterilization and processing, the amount of irradiated radiation can be reduced in a short time. It is necessary to know exactly.

[0003] For example, in a nuclear power plant, an area dose rate map based on a regular survey of fixed points is displayed at the entrance of a management area for the purpose of reducing exposure, and information on dose rates is provided to workers. However, if there is a highly sensitive radiation-sensitive substance that changes color even for low-level radiation actually detected in a nuclear power plant, workers can confirm the dose rate in real time by installing it on the wall etc. It is possible to manage radiation exposure efficiently.

On the other hand, in a sterilization / processing facility utilizing radiation irradiation, a radiation-sensitive substance from low sensitivity to high sensitivity is required in order to change the radiation dose depending on the object.

[0005]

There are already known substances which change color or the like (discoloration / coloration) in response to radiation, but existing radiation-sensitive substances are discolored or discolored by radiation.
The radiation dose required for color development is extremely high (thousands
(rad or more), it is insensitive to radiation that reaches harmful levels to the human body. Therefore, it is difficult to use it for controlling the exposure of workers in nuclear power plants and facilities that handle radiation (radiation elements) and the like.

On the other hand, in a sterilization / processing facility using irradiation of radiation, a radiation-sensitive substance has already been used as a means for visually confirming that predetermined radiation has been irradiated in a short time. However, the fact that the radiation dose at which discoloration / coloration of the substance starts is high, and the magnitude of the radiation dose based on the degree of discoloration / coloration cannot be accurately determined by visual confirmation, resulting in irradiation of radiation more than necessary. However, there is a problem that high cost processing is required.

An object of the present invention is to provide a high-sensitivity radiation-sensitive substance that exhibits a color change even with low-level radiation, unlike a conventional low-sensitivity radiation-sensitive substance, and a radiation detection method using the same. Aim.

The radiation-sensitive substance according to the first aspect of the present invention comprises, as a main component, an acid-generating substance which decomposes upon irradiation with radiation to generate an acid, and a pigment which generates color or changes color by the generated acid. in the radiation sensitive material which, under
An acid generator having a skeleton represented by the chemical formula 5
It is mainly composed of a color pigment or a pH indicator.
The rings A and B in the formula are each a 5- or 6-membered group which may have a substituent.
Aromatic ring members, indicates a heterocyclic ring, X ^- is shown an anion
You.

[0009]

[0010]

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[0011]

The radiation-sensitive substance according to the second aspect of the present invention is the radiation-sensitive substance according to the second aspect, wherein the leuco dye according to the second aspect comprises the following:
It is selected from those having a skeleton represented by the chemical formula of Chemical Formula 6 or Chemical Formula 7 . The substituents R ₁ , R ₂ , R _{3 in} the formula
Represents an independent substituent.

[0013]

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[0014]

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According to a third aspect of the present invention, there is provided a radiation detecting method using the radiation sensitive substance according to the first or second aspect , wherein the acid generating substance and the dye are dissolved in a solvent. Alternatively, a method is provided in which a sensitive test tool dispersed in a carrier is obtained, and radiation is detected by visually observing the color development or change in color of the sensitive test tool that has been irradiated.

According to a fourth aspect of the present invention, there is provided the radiation detecting method according to the third aspect , wherein the acid generating substance having a skeleton represented by the chemical formula (5) , a leuco dye or This is a method of obtaining a sensitivity test tool in which a pH indicator and a solvent are dispersed in a solvent or a carrier, and visually detecting the color development or change in color of the radiation-sensitive test tool to detect radiation.

According to a fifth aspect of the present invention, there is provided a radiation detecting method according to the third or fourth aspect , wherein a dispersion concentration of the acid generating substance is changed.
This is a method of changing the radiation dose threshold.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In order to realize a radiation-sensitive substance exhibiting high sensitivity to low-level radiation, the present inventors have developed a substance comprising a photoacid generator which generates an acid upon irradiation with ultraviolet rays and a functional dye. As a result of intensive research based on the technical idea that is effective, for example, diphenyliodonium
The present inventors have found that they can be formed by using a salt acid generator and a leuco dye or a pH indicator, and have reached the present invention. Ma
Further, the comparison of diphenyliodonium salt used in the present invention and
To obtain a triphenyl having a skeleton represented by the following chemical formula:
Disclosed are nilsulfonium salts. The rings A, B,
C is a 5- or 6-membered aromatic group which may have a substituent
Ring represents a heterocyclic ring, X ^- represents an anion. Release of the present invention
Radiation-sensitive substances cause some of the acid generator to be separated by radiation.
To generate acid, and the generated acid is leuco dye or pH indicating
Visualize the drug by changing its color or changing its color
Radiation.

[0019]

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In the present invention, specifically ,
The main component is an acid generator having a skeleton represented by the chemical formula of 5, and a leuco dye or a pH indicator. In the formula, rings A and B represent a 5- or 6-membered aromatic or heterocyclic ring which may have a substituent, and X ⁻ represents an anion. Further, even a 5- or 6-membered ring containing a nitrogen atom may have a sulfur atom or the like as a hetero atom in addition to the nitrogen atom.

The 5- or 6-membered aromatic ring includes a benzene ring of the following formula (9), a naphthalene ring of the following formula (10),
A thiophene ring of formula 11, a thiazole ring of formula 12,
And a pyridine ring.

[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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R _{4 in} Chemical formulas 9 to 13 represents a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an alkylamino group, an acylamino group, a halogen atom, Atom, other, ester group, cyano group, nitro group, thioether group, carbonyl group, sulfonyl group, amino group, substituted amino group, amide group, thioamide group, hydroxyl group, thiol group, carboxylic acid ester group or sulfone Examples include an acid group, a furyl group, and a tetrahydrofuryl group.

The alkyl which may have a substituent includes
Methyl group, ethyl group, n-propyl group, n-butyl group, n
-An unsubstituted alkyl group having 1 to 8 carbon atoms such as a hexyl group and an n-octyl group; having 1 to 4 ether groups such as a methoxyethyl group, an ethoxyethyl group, a methoxypropyl group and a methoxyethoxyethoxyethyl group; And an alkyl group.

The alkoxy group which may have a substituent has a carbon number such as methoxy group, ethoxy group, n-propyloxy group, n-butyloxy group, n-hexyloxy group and n-octyloxy group. 1 to 8 unsubstituted alkoxy groups; and alkoxy groups having 1 to 4 ether groups such as methoxyethoxy group, ethoxyethoxy group, methoxypropyloxy group, and methoxyethoxyethoxyethoxy group.

Examples of the alkylamino group include a tertiary amino group such as a dimethylamino group, a diethylamino group and a dipropylamino group, and a secondary amino group such as a methylamino group, an ethylamino group and a propylamino group.

Examples of the acylamino group include an alkylcarbonylamino group such as an acetylamino group and a propionylamino group, and examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Two or more of these substituents may be bonded.

[0032] Incidentally, X ^- as an anion represented by the, C
l ^-, Br ^- or I ^- halogen ions _{such, CH 3 - (C 6 H} 6) -SO 3
_{^{-, ClO 4 -, CH 3}} SO 3 -, BF 4 -, _{or, (C 6 H 6) 4} -B -, SbF 6 -,
_{^{CF 3 SO 3 -, PF 6}} - or the like can be mentioned.

Specific examples of the coloring matter which changes color or changes its color by the acid generated from the acid generator of the radiation-sensitive substance of the present invention include a leuco dye and a pH indicator. pH indicators include phenolphthalein, neutral red, thymol blue, alizarin.

The leuco dye may be any as long as it causes coloration or color change by an acid. Preferably, the leuco dye is selected from those having a skeleton represented by the above-mentioned chemical formula ( 6) or (7 ). is there.

The acid generator represented by Chemical Formula 5 of the present invention (diff
Principal specific examples of suitable compounds of the leuco dye represented by Chemical Formula 6 and Chemical Formula 7 are shown in the following Chemical Formulas 14 to 27. In addition, as a comparison of the present invention, it is shown in Chemical formula 8.
A triphenylsulfonium salt represented by the following chemical formulas
Specific examples of suitable compounds of the leuco dye
Shown in

[0036]

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[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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[0050]

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[0051]

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[0052]

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[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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According to the present invention, a radiation-sensitive irradiation device is obtained by obtaining a sensitive test device in which an acid generator having a skeleton represented by the above formula and a leuco dye or a pH indicator are dispersed in a solvent or a carrier. The radiation is detected by visually recognizing the color development or color change of the sensitized test tool.

Specifically, the solvent or carrier in which the acid generator and the leuco dye or pH indicator are dispersed include, for example, water, ethanol, acetone, chloroform and polymers. In these solvents or carriers, the acid generator is decomposed by irradiation with gamma rays or the like, and further reacts with the solvent or the polymer matrix to dissociate hydrogen ions (acids).

FIG. 1 shows an acid generation mechanism of a diphenyliodonium salt and a triphenylsulfonium salt by a radiation chemical reaction. The generated acid can react with a leuco dye having a lactone ring to form a color. Also, as a dye pH
When an indicator is used, the pH changes due to the acid generated by gamma irradiation, and the color changes. In the present invention, radiation is detected using such a radiation-sensitive acid generator and a functional dye.

[0065]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples unless it exceeds the gist.

Example 1 As the acid generator, the above-mentioned leuco dye (Chem. 28; crystal violet lactone 1m) was used.
M) and diphenyliodonium salt (Formula 15; 1 mM, 1 mM
(0 mM or 20 mM) was dissolved in ethanol, taken in 20 ml aliquots into test tubes, irradiated with 60-Co gamma rays, and the presence or absence of color development of the solution was evaluated from the change in absorbance.

FIG. 2 shows a change in color development of a diphenyliodonium salt-ethanol-crystal violet lactone solution by gamma ray irradiation as a change in absorbance. As shown in FIG. 2, the solution before gamma ray irradiation is colorless and transparent, and has an absorbance of zero, but the absorbance linearly increases with irradiation. The rate of change of the absorbance with respect to the irradiated radiation dose increases as the concentration of the diphenyliodonium salt increases, and color development becomes visible from a lower radiation dose.

Generally, the amount of change in absorbance at which color development can be visually identified is about 0.05, but in this embodiment, it is 10 rad.
A change in absorbance of about 0.05 was obtained even at such a low radiation dose, and no substance having such a property as to show visual color change at such a low radiation dose has been known so far.

Also, as can be seen from FIG. 2, the threshold value of the radiation dose at which the color change can be visually recognized (the radiation dose when the absorbance change is 0.05) depends on the concentration of the diphenyliodonium salt. By performing the density adjustment, it is possible to make the color change visible when a specific radiation dose is reached. Therefore, by arranging the solutions in which the concentration of the diphenyliodonium salt is continuously changed, a radiation detection device capable of discriminating a wide range of radiation dose from a low radiation dose to a high radiation dose can be obtained.

In the case of this radiation detection device, the radiation dose is determined not by the degree of discoloration or coloration of the substance but by the presence or absence of color development from colorless and transparent. Therefore, it is necessary to grasp the radiation dose sufficiently visually. Is possible.

The diphenyliodonium salt can be used in any form of a liquid or a solid such as a film, and can be used for detection of X-rays, ultraviolet rays, etc. in addition to the gamma rays described in Examples. It was confirmed that.

Example 2 Thymol Blue (2.0 × 1
0 ^-5 M) and the diphenyliodonium salt (Formula 15;
An aqueous solution consisting of 2.3 × 10 ⁻⁴ M) is prepared, and the solution is adjusted to pH
= 9.7. Each 20 ml of the blue aqueous solution thus prepared was placed in a test tube, irradiated with 60-Co gamma rays, and the color change of the solution was evaluated from the change in absorbance.

FIG. 3 shows the results. Although the solution before gamma ray irradiation was blue (the main absorption wavelength was 594 nm), the absorbance at 594 nm decreased with gamma ray irradiation, and the
The absorbance in the nm absorption band increased and the color of the solution changed from blue to yellow, indicating that a color change was recognizable from such a low radiation dose.

As described above, the radiation detector using an acid generator according to the present invention enables visual confirmation of low-level radiation detected in a nuclear power plant or a facility that handles radiation (radioactive substances). Therefore, the radiation exposure can be reduced by the efficient radiation management of the worker.

Further, even in a sterilization / processing facility utilizing irradiation of radiation, unlike an existing low-sensitivity radiation-sensitive substance, it is possible to monitor in detail a range from a low radiation dose to a high radiation dose. Therefore, it is possible to reduce the irradiation cost by not irradiating excessive radiation more than necessary.

[0076]

As described above, the present invention has an effect that it is possible to obtain a highly sensitive radiation-sensitive substance showing a color change even with low-level radiation and a radiation detection method using the same.

[Brief description of the drawings]

FIG. 1 shows diphenylyo as a radiation-sensitive substance of the present invention.
Triphenylsulfonium as a comparison with rhodium salts
It is an explanatory view showing an acid generation mechanism with a salt. FIG. A shows the acid generation mechanism of a diphenyliodonium salt, and FIG.

FIG. 2 is a diagram showing a change in color development by gamma ray irradiation according to an embodiment of the radiation-sensitive material of the present invention.

FIG. 3 is a graph showing a change in absorbance according to an embodiment of the radiation-sensitive substance of the present invention.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mikio Sakaya 1-6-1, Otemachi, Chiyoda-ku, Tokyo Japan Atomic Energy Company, R & D Division (72) Inventor Tetsuhiro Nakagoshi 1 Otemachi 1, Chiyoda-ku, Tokyo −6-1 Japan Nuclear Power Co., Ltd. Research and Development Division Research and Development Department (72) Inventor Takeshi Sakai 950 Noda, Kazatori-cho, Sennan-gun, Osaka Atomic Fuel Industry Co., Ltd. Engineering Service Department (72) Inventor Noboru Nakagome Sennan, Osaka 950, Noda, Kumatori-cho, Gunma Nuclear Fuel Industry Co., Ltd. Engineering Service Department (72) Inventor Hiroyuki Nakasumi 6-15 Midorigaoka Minamicho, Kawachinagano-shi, Osaka 4-87 Oyasha (72) Inventor Masakazu Yoshida 5-5-Toyosaki, Kita-ku, Osaka-shi, Osaka 24-605 (56) References JP-A-63-229386 (JP, A) Japanese Translation of PCT International Publication No. 1-502699 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01T 1/04

Claims (5)

(57) [Claims] 1. A radiation-sensitive substance containing, as a main component, an acid-generating substance which decomposes upon irradiation with radiation to generate an acid, and a dye which produces a color or a color change by the generated acid, represented by the following chemical formula 1. An acid generator having a skeleton,
A radiation-sensitive substance comprising a leuco dye or a pH indicator as a main component . Embedded image (Wherein, rings A and B represent a 5- or 6-membered aromatic or heterocyclic ring which may have a substituent, and X ⁻ represents an anion.) 2. The radiation-sensitive substance according to claim 2, wherein the leuco dye is selected from those having a skeleton represented by the following chemical formula (3) or (4). Embedded image Embedded image (In the formula, the substituents R ₁ , R ₂ , and R ₃ each represent an independent substituent.) 3. A radiation detection method using the radiation-sensitive substance according to claim 1 or 2 , wherein the acid-generating substance and a dye are dispersed in a solvent or a carrier to obtain a sensitivity inspection tool. A radiation detection method, characterized in that radiation is detected by visually recognizing the color development or color change of a sensitive test tool to which radiation has been applied. 4. The radiation detection method according to claim 3 , wherein the acid generator having a skeleton represented by the chemical formula :
Obtaining a sensitivity test device in which a leuco dye or a pH indicator is dispersed in a solvent or a carrier, and detecting radiation by visually observing the color development or change in color of the sensitivity test device subjected to irradiation. Radiation detection method. 5. varying the dispersion concentration of the acid-generating substance, characterized in that changing the threshold value of the radiation amount according
Item 6. The radiation detection method according to item 3 or 4 .