JP3131878B2 - 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.

[0008]

The radiation-sensitive substance according to the first aspect of the present invention contains, as a main component, a coloring matter which is decomposed by irradiation with radiation to form a color. That is,
The radiation-sensitive substance according to the invention is emitted by irradiation of radiation.
It is a coloring dye, which is mainly composed of a leuco dye represented by the following chemical formula (1) or (2). The rings A, B, and C in the formula represent a 5- or 6-membered aromatic or heterocyclic ring which may have a substituent.

[0009]

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[0010]

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According to a second aspect of the present invention, there is provided a radiation detecting method using the radiation sensitive substance according to the first aspect, wherein the acid generating substance and the dye are contained in a solvent or a carrier. This is a method of obtaining a radiation-sensitive inspection tool dispersed therein, and visually detecting the color development or color change of the radiation-induced radiation-sensitive inspection tool to detect radiation. That is, radiation
A sensitivity test device in which a leuco dye having a skeleton represented by the chemical formula (1) or (2) is dispersed in a solvent or a carrier as a dye that develops color upon irradiation with a ray, and the radiation test is performed. This is a method of detecting radiation by visually checking the color development or color change of the tool.

The radiation-sensitive substance according to the third aspect of the present invention is mainly composed of a pigment which decomposes upon irradiation with radiation to form a color. That is, the radiation-sensitive substance according to the present invention is a dye that develops color when irradiated with radiation.
And a diacetylene derivative having a linear alkyl group structure as a main component.

According to a fourth aspect of the present invention, there is provided a radiation detecting method using the radiation sensitive substance according to the third aspect, wherein the acid generating substance and the dye are contained in a solvent or a carrier. This is a method of obtaining a radiation-sensitive inspection tool dispersed therein, and visually detecting the color development or color change of the radiation-induced radiation-sensitive inspection tool to detect radiation. That is, radiation
As a dye that develops color upon irradiation with a ray, a diacetylene derivative having a straight-chain alkyl group structure is obtained in a solvent or a carrier to obtain a sensitivity test device, and the color or color of the sensitivity test device irradiated with radiation is obtained. This is a method of detecting radiation by visually observing a change in.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have concluded that, in order to realize a radiation-sensitive substance having a high sensitivity to low-level radiation, a technique comprising a substance comprising a functional dye which develops a color by irradiation with ultraviolet light is effective. As a result of intensive research based on the idea, they have found that they can be formed by using, for example, a triarylmethane-based leuco dye, a diarylmethane-based leuco-dye, a solvent, and a polymer, and have reached the present invention.

In the radiation-sensitive substance of the present invention, a part of the leuco dye or the medium is decomposed by irradiation with radiation to generate radicals, which react with the leuco dye to generate triarylmethane or diarylmethane radicals. Oxidized to form a triaryl metanium or diaryl metanium cation to develop color and visually detect radiation.

In the present invention, specifically, a leuco dye having a skeleton represented by the above-mentioned chemical formula 3 or 4 is mainly used. The rings A, B, and C in the formula are
A 5- or 6-membered aromatic ring which may have a substituent,
Shows a heterocyclic ring. 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.

As the 5-membered or 6-membered aromatic ring,
Examples thereof include a benzene ring of Chemical Formula 5, a naphthalene ring of Chemical Formula 6, a pyridine ring of Chemical Formula 7, a thiophene ring of Chemical Formula 8, an indole ring of Chemical Formula 9, and the like.

[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023] Incidentally, ¹ R of Compound 5 of ^{9, 2 R, 3 R,} 4 R
Is a hydrogen atom, an alkyl group which may have a substituent,
Optionally substituted alkoxy group, alkylamino group, acylamino group, halogen atom, and other substituents such as ester group, cyano group, nitro group, thioether group, carbonyl group, sulfonyl group, amino group, substituted amino Groups, amide groups, thioamide groups, hydroxyl groups, thiol groups, carboxylic acid ester groups or sulfonic acid groups, furyl groups, tetrahydrofuryl groups, and the like.

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

The alkoxy group which may have a substituent has a carbon number such as a methoxy group, an ethoxy group, an n-propyloxy group, an n-butyloxy group, an n-hexyloxy group and an 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.

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

Preferred specific examples of the preferred leuco dye compounds represented by Chemical Formulas 3 and 4 of the present invention are shown in the following Chemical Formulas 10 to 15.

[0029]

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[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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In the present invention, a sensitive test device in which a leuco dye having a skeleton represented by the chemical formula (1) or (2) is dispersed in a solvent or a carrier is obtained. Radiation is detected by visually confirming color development or color change.

Specifically, the solvent or carrier includes, for example, ethanol, acetone, chloroform and a polymer, and a halogen solvent such as chloroform is particularly preferable. In these solvents or carriers, the leuco dye or the solvent (or polymer) is radically decomposed by irradiation with gamma rays or the like, and the oxidation reaction further proceeds, thereby generating the cation of triphenylmethane (triphenylmethane dye). I do.

FIG. 1 shows the mechanism of dye generation by the radiation chemical reaction of triphenylmethane. The generated radicals produce triphenylmethane radicals, which can then become cations in an oxidation reaction to develop color. In the present invention, radiation is detected using a functional leuco dye having sensitivity to such a radiation and a solvent or a polymer that holds the dye in a dispersed state.

Another radiation-sensitive substance of the present invention discloses, as a dye which decomposes and develops a color when irradiated with radiation, a substance mainly composed of a diacetylene derivative having a linear alkyl group structure. Specific diacetylene derivatives having a straight-chain alkyl group structure include 3 at the 10- and 12-positions.
Nonacosa-10,12-diynoic acid having a heavy bond and tricosa-1
0,12-dinoic acid (tricosa-10,12-diynoic a
cid).

[0039]

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 A leuco dye (formula 11; bis (p-dimethylaminophenyl)-(p-methoxyphenyl) methane 1.0 mM) was added to chloroform (1000 m
The solution was dissolved in 1), 20 ml of each solution was placed in a test tube, and irradiated with ⁶⁰ CO gamma rays, and the presence or absence of color development of the solution was evaluated from the change in absorbance. The results are shown in FIG. It was found that blue was produced at such a low radiation dose.

FIG. 2 shows the change in color development of a leuco dye (formula 11) -chloroform 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 the absorbance is zero.
Absorbance increases linearly with irradiation. The rate of change of the absorbance with respect to the irradiated radiation dose increases as the concentration of the leuco dye increases, and the color development becomes visible from a lower radiation dose.

[0042] [Example 2] leuco dye (Formula 11, bis (p- dimethylaminophenyl) - (p- methoxyphenyl) methane 1.0 mM) taken in a test tube with 20ml each was dissolved in ^{ethanol, 60}
The solution was irradiated with CO gamma rays, and the presence or absence of color development of the solution was evaluated from the change in absorbance. The results are shown in FIG. 3 in comparison with Example 1. In the figure, ○ indicates the present embodiment, and ● indicates the first embodiment. Although the sensitivity was lower than that of chloroform, color formation was observed at 30 Gy.

In general, the amount of change in absorbance at which color development can be visually identified is O.D. However, in the case of this embodiment, it is 1
A radiation dose of about 0 rad (0.1 Gy) is about O.D. 05
, And a substance having a property of visually exhibiting a color change at such a low radiation dose has not been known so far.

In the case of this radiation detection device, the radiation dose is determined not by the degree of coloration of the substance but by the presence or absence of color development from colorless and transparent, so that the radiation dose can be grasped sufficiently visually. It is.

The triphenylmethane leuco dye can be used in any form of a liquid or a solid such as a film. In addition to the gamma rays described in Examples,
It was confirmed that it can be used for detection of X-rays, ultraviolet rays and the like.

Example 3 For each of the diacetylene derivatives shown in Table 1, about 2 mg of solid powder (pellets having a diameter of 5 mm) was prepared, irradiated with 0.2 to 3 Gy of 60Co-γ-rays, and examined for color development. , And γ from the measurement of the reflection spectrum
The sensitivity to the line was evaluated.

[0047]

[Table 1]

As shown in Table 1, diacetylene derivatives having a long-chain alkyl group as a substituent (nonacosa-10,12-diynoic acid of diacetylene derivative 1, and tricosa-10,12 of diacetylene derivative 2) 12-diynoic acid)
Upon gamma irradiation, polymerization occurred in the solid state, and the color changed from colorless to blue. FIG. 4 is a diagram showing a reflection spectrum of the diacetylene derivative 1. FIG. 5 is a diagram showing a reflection spectrum of the diacetylene derivative 2. In the figure, the vertical axis indicates the reflectance (%), and the horizontal axis indicates the wavelength (nm).

As described above, the radiation detector using leuco dye of the present invention enables visual confirmation of low-level radiation detected in a nuclear power plant or a facility handling radiation (radioactive substances). Therefore, it is possible to reduce the exposure by efficient exposure 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 closely monitor 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.

[0051]

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 is an explanatory view showing a color forming mechanism of a typical leuco dye of the radiation-sensitive substance of the present invention.

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.

FIG. 4 is a diagram illustrating a reflection spectrum according to another embodiment of the radiation-sensitive material of the present invention.

FIG. 5 is a diagram showing a reflection spectrum according to another embodiment of another radiation sensitive material of the present invention.

Continued on the front page (72) Inventor Hiroyuki Nakasumi 6-15, Midorigaoka Minamicho, Kawachinagano City, Osaka Prefecture (72) Inventor Toshiro Hayashi 4-87, 23, Ono Shiba-cho, Sakai City, Osaka Prefecture 4-87 (72) Inventor Furuta Masakazu 5-5-605 Toyosaki, Kita-ku, Osaka-shi, Osaka (56) References JP-A-10-16410 (JP, A) JP-A-7-12940 (JP, A) JP-A-63-221278 ( JP, A) JP-A-3-65947 (JP, A) JP-A-10-287055 (JP, A) JP-A-10-239794 (JP, A) JP-A-11-258347 (JP, A) Hei 6-506784 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01T 1/04

Claims (4)

(57) [Claims] 1. A dye which develops color upon irradiation with radiation.
Thus, a radiation-sensitive substance comprising a leuco dye represented by the following chemical formula 1 or 2 as a main component. Embedded image Embedded image (In the formula, rings A, B and C represent a 5- or 6-membered aromatic ring or heterocyclic ring which may have a substituent.) 2. The method for detecting radiation using a radiation-sensitive substance according to claim 1 , wherein a leuco dye having a skeleton represented by the chemical formula (1) or (2) is used as a dye to be colored by irradiation with radiation. What is claimed is: 1. A radiation detection method comprising: obtaining a sensitive test tool dispersed in a medium or a carrier; and visually detecting a color or a change in color of the sensitive test tool irradiated with the radiation to detect radiation. 3. A dye which is colored by irradiation with radiation.
A radiation-sensitive substance comprising, as a main component, a diacetylene derivative having a linear alkyl group structure. 4. The method for detecting radiation using a radiation-sensitive substance according to claim 3 , wherein the diacetylene derivative having a straight-chain alkyl group structure is contained in a solvent or a carrier as a dye that develops color upon irradiation with radiation. What is claimed is: 1. A radiation detection method, comprising: obtaining a dispersed sensitivity inspection tool; and visually detecting a color or a change in color of the radiation-exposed sensitivity inspection tool to detect radiation.