JPS61157573A - Fluorescent substance and radiation image conversion panel using same - Google Patents

Abstract

PURPOSE:A divalent europium-activating alkaline earth metal fluoride halide fluorescent substance that is given with a specific constitution formula, thus giving radiation image conversion panel with improved after-image properties, because it has excellent emission stimulation. CONSTITUTION:The objective fluorescent substance is represented by the constitution formula: MIIFX.aNaX'.bA:xEu<2+> (MII is Ba, Ca, Sr; X, X' are Cl, Br, I; A is InF3, In2O3; a, b, x are 0<a<=2.0, 3X10<-4=b<=2X10<-2>, 0<x<=0.2). The objective fluorescent substance is prepared by mixing an alkaline earth metal fluoride, an alkaline earth metal halide, indium fluoride and/or indium oxide, sodium halide and an europium compound, e.g., in the form of a suspension, removing water from the mixture, then, roasting the fine particles of the mixture at 500-1,300 deg.C in an electric furnace for 0.5-6hr.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a phosphor and a radiation image conversion panel using the same. More specifically, the present invention relates to a divalent europium-activated alkaline earth metal fluorohalide phosphor and a radiation image conversion panel using this phosphor.

[Technical Background of the Invention and Prior Art 1] In recent years, alkaline earth metal fluoride halide phosphors activated with divalent europium (MTOFX: E
u'''; However, MW is at least one kind of alkaline earth metal selected from the group consisting of Ba, Ca, and Sr, and X is at least one kind of halogen selected from the group consisting of C1, Br, and When it is irradiated with radiation such as X-rays, it absorbs and accumulates a part of its energy, and then when it is irradiated with electromagnetic waves in the wavelength range of 450 to 900 nm, it emits light in the near ultraviolet to blue region. It has been found that the phosphor exhibits stimulated luminescence (the peak wavelength of this stimulated luminescence is approximately 385 to 405 nm depending on the type of halogen X that is a component of the phosphor).
In particular, this divalent europium-activated alkaline earth metal has attracted much attention as a phosphor for radiation image conversion panels (stimulable phosphor sheets) used in radiation image recording and reproducing methods, and has been used in many Research is being conducted.

The basic structure of the radiation image storage panel is a support,
The phosphor layer is formed of a binder containing and supporting at least one stimulable phosphor in a dispersed state, provided on one side of the phosphor layer. Note that a transparent protective film is generally provided on the surface of the phosphor layer opposite to the support (the surface not facing the support) to protect the phosphor layer from chemical deterioration or Protects from physical impact.

The radiation image recording and reproducing method using the radiation image conversion panel made of the above-mentioned stimulable phosphor is an effective alternative to the conventional radiography method.
As described in the above publication, the radiation energy transmitted through the subject or emitted from the subject is absorbed by the stimulable phosphor constituting the radiation image conversion panel,
Thereafter, by exciting the stimulable phosphor in a time-series manner with electromagnetic waves (excitation light) selected from visible light and infrared rays, the radiation energy accumulated in the stimulable phosphor is released as fluorescence, After photoelectrically reading this fluorescence to obtain an electrical signal, this electrical signal is reproduced as a visible image on a recording material such as a photosensitive film or a display device such as a CRT.

This method has the advantage that it is possible to obtain a radiographic image rich in information with a much lower exposure dose than when using conventional radiography. Therefore, the radiographic image recording and reproducing method is extremely useful, especially in direct medical radiography such as X-ray photography for the purpose of medical diagnosis.

In carrying out the above-mentioned radiation image recording and reproducing method, the radiation image conversion panel itself hardly changes in quality even when irradiated with radiation and excitation light, so that it can be used repeatedly over a long period of time. Normally, to read out the radiation energy accumulated in a panel, a laser beam is used as excitation light, and the panel is first scanned with this laser beam to excite the stimulable phosphor in the panel in a time-series manner. This is done by emitting the accumulated radiation energy as fluorescence, and then detecting this fluorescence with a photodetector.

In actual use, the radiation energy accumulated in the panel is not fully released by scanning with laser light alone, so in order to release the radiation energy remaining in the panel, for example, Japanese Patent Application Laid-Open No. 56-11392 As disclosed in , a method has been proposed in which after the panel is read out, the panel is irradiated with light in the excitation wavelength region of stimulated luminescence of the phosphor to erase the remaining radiation energy.

However, in panels containing stimulable phosphors, after the radiation energy is erased by light as described above, some of the radiation energy that once appeared to be erased recovers over time (readout A phenomenon has been discovered that makes it possible. This phenomenon (afterimage characteristic) is caused by radiation energy (
This is thought to be due to the fact that energy is actually stored in the form of electrons in the playing cards), but over time it is converted into radiation energy that can be easily released (electrons move from the playing cards, where they are difficult to release, to traps where they are easy to release). It will be done. If the panel is used repeatedly, this afterimage characteristic will adversely affect the quality of the resulting image.

Therefore, it is of great significance to improve the afterimage characteristics, which have a negative impact on image quality, by reducing the amount of residual radiation energy that cannot be removed by optical erasing and is likely to be released over time after optical erasing. be.

The present applicant has proposed a phosphor comprising a divalent europium activated barium fluoride halide phosphor containing a specific amount of sodium halide, which is a type of phosphor, for the purpose of improving the stimulated luminance of the phosphor. We have already applied for (
(Japanese Unexamined Patent Publication No. 59-56479). This sodium halide-containing divalent europium activated fluoride halogenated paris/1υ \11 lI 1 , 1
-1 nail 1 1 11 mountain, book, pu J-
It exhibits stimulated luminescence with higher brightness than the Q4 phosphor, but on the other hand, the stimulated luminescence characteristics described above tend to deteriorate. Therefore, it is desired to improve the stimulated luminescence properties of a sodium halide-containing divalent europium-activated barium fluoride halide phosphor.

[Summary of the Invention] An object of the present invention is to provide a divalent europium-activated alkaline earth metal fluorohalide-based phosphor with improved stimulated luminescence properties. In addition, in the present invention, improvement in stimulated luminescence properties is particularly defined when a phosphor is irradiated with radiation, once excited with excitation light, further erased with light, and then excited again with excitation light after a certain period of time has elapsed. This means that the amount of residual light emission is reduced.

Another object of the present invention is to provide a radiation image conversion panel using a divalent europium-activated alkaline earth metal fluorohalide phosphor with improved afterimage characteristics.

In order to achieve the above object, the present inventors conducted various studies on divalent europium-activated alkaline earth metal fluorohalide-based phosphors containing sodium halide. As a result, the inventors discovered that by containing indium fluoride and/or indium oxide in a certain range in the phosphor, the stimulated luminescence properties of the phosphor can be significantly improved, and the present invention has been achieved. .

That is, the phosphor of the present invention has a composition formula (I): M"FX
*aNaX' e bA:xEu2+...(I) (However, Ml is at least one alkaline earth metal selected from the group consisting of Ba, Ca, and Sr;
and X゛ are both C! ; L, Br and I are also at least one kind of halogen selected from the group consisting of; A is at least one kind selected from the group consisting of InF3 and In2O3; and a, b and X are each 0<a≦2 .0.3 X 10-'≦b≦2X 10
divalent europium-activated alkaline earth containing a specific amount of indium fluoride and/or indium oxide in addition to a specific amount of sodium halide, represented by It is a metal fluoride halide phosphor.

Further, the radiation image conversion panel of the present invention is a radiation image conversion panel substantially composed of a support and a photostimulable phosphor layer provided thereon, in which the photostimulable phosphor layer comprises: It is characterized by containing a divalent europium-activated alkaline earth metal fluorohalide-based phosphor represented by the above compositional formula (I).

The present invention provides the stimulated luminescence amount (initial A new finding that the stimulated luminescence amount (residual luminescence amount) is significantly reduced when this excitation is followed by erasure and the phosphor is again excited with excitation light after a certain period of time. It was completed based on.

Therefore, the radiation image storage panel of the present invention using the divalent europium-activated alkaline earth metal fluorohalide phosphor represented by the above compositional formula (I) has improved image retention characteristics, and therefore has excellent image quality. Images can be obtained constantly.

[Structure of the Invention] The divalent europium-activated alkaline earth metal fluoride halide phosphor of the present invention represented by the above compositional formula (I) comprises:
For example, it can be manufactured by the manufacturing method described below.

First, as a phosphor raw material, from the group consisting of (1) alkaline earth metal fluoride, 2) alkaline earth metal halide (excluding alkaline earth metal fluoride), and 3) indium fluoride and indium oxide. At least one selected compound, 4) Sodium halide (excluding sodium fluoride), and 5) Halides, oxides, nitrates, sulfates, etc.^1-
--^1. / Pi ru Δ bill yu, r bl 'It★μL
1) Prepare at least one type of compound. In some cases, ammonium halide or the like may also be used as a flux.

When producing a phosphor, first, the above alkaline earth metal fluoride (1), the alkaline earth metal halide (2), and 3.
) of indium fluoride and/or indium oxide, 4
) and the europium compound of 5), the composition formula (■): M"FX* aNaX' * bA: xEu (I
) (However, the definitions of Ml, X, X', A, a, b and

The above mixture operation is carried out, for example, in the form of a suspension. Then, by removing water from the suspension of this phosphor raw material mixture, a solid dry mixture can be obtained.

This moisture removal operation is carried out by drying under reduced pressure MA,
It is preferable to carry out air drying or both, but the mixing operation is not limited to the above method.

Note that the indium fluoride and/or indium oxide in 3) above and the sodium halide in 4) may be added to this dry mixture without being added at the time of weighing and mixing the phosphor raw materials. Furthermore, when the dry mixture is fired more than once as described below, the compounds 3) and 4) may be added after the first firing.

Next, the obtained dry mixture is finely pulverized, and the pulverized product is filled into a heat-resistant container such as a quartz port or an alumina crucible, and fired in an electric furnace. Firing temperature is 50
A temperature in the range of 0 to 1,300° C. is appropriate, and the firing time varies depending on the amount of the phosphor raw material mixture filled and the firing temperature, but in general, 0.5 to 6 hours is appropriate. As the firing atmosphere, a weakly reducing atmosphere such as a nitrogen gas atmosphere containing a small amount of hydrogen gas or a carbon dioxide atmosphere containing -carbon oxide is used. When the europium compound used contains trivalent europium, the weakly reducing atmosphere reduces the trivalent europium to divalent europium during the firing process.

It should be noted that a method may be used in which the phosphor raw material mixture is once fired under the above firing conditions, and then the fired product is left to cool, then pulverized, and then re-fired (secondary firing). The firing process is carried out in a weakly reducing atmosphere such as , or a neutral atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere at a firing temperature of 500 to 800° C. for 0.5 to 12 hours.

The phosphor of the present invention in powder form is obtained by the above baking.

Note that the obtained powdered phosphor may be further subjected to various general operations in the production of phosphors, such as washing, drying, and sieving, as necessary.

By the manufacturing method described above, the divalent europium-activated alkaline earth metal fluorohalide phosphor of the present invention represented by the following compositional formula CI) can be obtained.

Compositional formula (I): MIIIFX・aNaX' * bA: xEu2+
...(I) (However, Ml[ is at least one alkaline earth metal selected from the group consisting of Ba, Ca, and Sr;
Both X and X' are at least one kind of halogen selected from the group consisting of Cl, Br and I; A is I
is at least one selected from the group consisting of nF3 and In2O3; and a, b and 450 to 900 nm after irradiation with radiation such as X-rays in the phosphor of the present invention represented by the above compositional formula (I)
From the viewpoint of stimulated luminescence characteristics (ratio of residual luminescence amount/initial luminescence amount, that is, relative luminescence amount) when excited by electromagnetic waves in the wavelength range of NaX, which represents sodium halide, is in the range of 6X10'≦b≦10'4, mainly from the viewpoint of absolute luminescence amount (absolute value of initial luminescence amount).
' is preferably NaBr, and the a value representing its amount is preferably in the range of 10-≦a≦5XlO-', more preferably in the range of 5XlO''≦a≦10''.

From the above relative luminescence amount and absolute luminescence amount, the composition formula (I
), Ml representing the alkaline earth metal is preferably Ba, more preferably 1M as described in Japanese Patent Application No. 11763/1983 filed by the present applicant.
This is the case where the metal is composed of Ha, Ca and Sr, and the total amount of Ca and Sr is in the range of 5 x 104 (Durham equivalent) or less. The X value representing the activation amount of europium is lO4≦X
It is preferably in the range of ≦1O-1.

In the compositional formula CI), X representing halogen is preferably at least one of Br and Br from the viewpoint of absolute luminescence amount.As mentioned above, the stimulated excitation spectrum of the phosphor of the present invention has a length of 450. depends on halogen X
M, Br, and I gradually shift toward longer wavelengths in this order. Therefore, H
Also from the point of view of matching with e-Ne laser (633 nm), semiconductor laser (infrared radiation), etc., X representing halogen is preferably at least one of Br and I.

B a F B r -0,001N a B r which is an example of the phosphor of the present invention represented by the composition formula (I)
* bI n F 3 : 0.0005E u2+
For a radiation image storage panel having a phosphor layer containing a phosphor dispersed in a binder, InF in the phosphor
The b value representing the content of 3 and the relative luminescence amount have a relationship as shown in FIG. In Figure 1, for the relative luminescence on the vertical axis, after measuring the initial luminescence amount, the light was extinguished for about 3 minutes using a white fluorescent lamp, and then measured again under the same conditions at a temperature of 35°C for 3 hours. It is expressed as a relative value of the remaining luminescence amount (residual luminescence amount/initial luminescence amount).

As is clear from the curve l in FIG.
r medium 0.001 NaB r 11 b
I nF 3: o, ooo! The radiation image conversion panel containing 1iEu2+ phosphor has an indium fluoride content (Cb value) in the phosphor of 3×10″≦b≦2Xl
The residual luminescence amount decreases when it is in the range of O"" (
In other words, the afterimage characteristics are improved). And especially the b value is 6
When the range of X 10-''≦b≦10-2 is satisfied, the afterimage characteristics of the panel using this phosphor are significantly improved.

Curve 1 in FIG. 2 is [email protected], which is an example of the phosphor of the present invention represented by the above composition formula CI).
N aB r 11b I n203:0.0005E
Regarding a radiation image storage panel having a phosphor layer containing u'' phosphor dispersed in a binder, I
From Figure 2, which shows the relationship between the b value representing the content of n203 and the relative luminescence amount, it can be seen that when indium oxide is added instead of indium fluoride in a divalent europium-activated barium fluoride bromide phosphor, It is clear that the residual luminescence amount also decreases in the same way as above.

It has been confirmed that this tendency is the same in a radiation image storage panel using a divalent europium-activated alkaline earth metal fluorohalide phosphor represented by the composition formula (I).

The divalent europium-activated alkaline earth metal fluorohalide phosphor of the present invention has the above compositional formula CI) as its basic composition, and during its production, In
Various additive components may be added as long as the effect of adding F3 and/or In2O3 (reduction in residual luminescence amount) is not lost, and those containing such additive components are also included in the fluorescence of the present invention. included in the body. Specific examples of additive components include the following substances.

Metal oxides as described in JP-A-55-160078; Tetrafluoroboric acid compounds as described in JP-A-59-27980: JP-A-Sho 5
Hexafluoro compounds as described in JP-A-59-75200; Al as described in JP-A-59-75200 is Li, at least one alkali metal selected from the group consisting of Rb and C5; Yes, X
II is at least one halogen selected from the group consisting of F, Cl, Br and I), a halide of a divalent metal (M value
at least one divalent metal selected from the group consisting of F, C1, Br and I) and a trivalent metal halogen compound (M"X""3; however, yl
1 is at least one trivalent metal selected from the group consisting of An, Ga, and 1, and x'' is F, CM, B.
at least one halogen selected from the group consisting of r and I); Zr and Sc described in JP-A-56-116777; JP-A-57-23673
B described in JP-A-57-23675; As described in JP-A-57-23675; and JP-A-59-56
Transition metals such as those described in Publication No. 480.

F+ IRnA'; Mll tool 4＼
Addition of a metal oxide as described above is particularly effective in preventing sintering of the phosphor during the firing process and improving the stimulated luminescence brightness and powder fluidity of the obtained phosphor. When a metal oxide is added, the amount thereof is 5XlO'' to 0.5 mol, preferably t
o-'~0.3 mol, more preferably 10''~0.2
It is in the molar range. A particularly preferable metal oxide is S
iO□ and Ami203 are mentioned.

Next, a radiation image conversion panel according to the present invention will be explained.

The radiation image conversion panel of the present invention basically comprises a support,
A phosphor layer is provided thereon, and the phosphor layer is made of a binder containing and supporting a stimulable phosphor in a fractional state. For example, the phosphor layer is 1
It can be formed on the support by the following method.

First, particles of the stimulable phosphor represented by the above composition formula (I) and a binder are added to a suitable solvent, and the mixture is sufficiently mixed to coat the stimulable phosphor particles uniformly dispersed in the binder solution. Prepare the liquid.

Examples of binders for the phosphor layer include proteins such as gelatin,
Polysaccharides such as dextran, or natural polymeric substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethylcellulose, vinylidene chloride φ vinyl chloride copolymer, polyalkyl (meth)acrylate, vinyl chloride vinyl acetate Binders typified by synthetic polymeric materials such as copolymers, polyurethanes, cellulose acetate butyrate, polyvinyl alcohol, linear polyesters, etc. may be mentioned. Particularly preferred among such binders are nitrocellulose, linear polyesters, polyalkyl (meth)acrylates, mixtures of nitrocellulose and linear polyesters, and mixtures of nitrocellulose and polyalkyl (meth)acrylates. be. Note that these binders may be crosslinked with a crosslinking agent.6 Examples of solvents for preparing the coating solution include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; methylene chloride; , chlorine atom-containing hydrocarbons such as ethylene chloride; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters of lower acid and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; dioxane, ethylene glycol monoethyl ether , ethers such as ethylene glycol monomethyl ether; and mixtures thereof.

The mixing ratio of the binder and the phosphor in the coating solution varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, etc., but in general, the mixing ratio of the binder and the phosphor is
:1 to 1:1oO (weight ratio), and particularly preferably from 1:8 to 1:40 (weight ratio).

The coating solution also contains a dispersant to improve the dispersibility of the phosphor particles in the coating solution, and a dispersing agent of 1 μm is necessary for improving the dispersibility of the phosphor particles. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, etc., which may be mixed with various additives such as plasticizers to improve the bonding strength between , lipophilic surfactants, and the like. Examples of plasticizers include triphenyl phosphate, tricresyl phosphate,
Phosphate esters such as diphenyl phosphate; phthalate esters such as diethyl phthalate and dimethoxyethyl phthalate;
Glycolic acid esters such as ethyl phthalyl ethyl glycolate and butylphthalyl butyl glycolate; and polyesters of polyethylene glycol and aliphatic dibasic acids such as polyesters of triethylene glycol and adipic acid and polyesters of diethylene glycol and succinic acid. Examples include polyester.

The coating solution containing the phosphor particles and binder prepared as described above is then uniformly applied to the surface of the support to form a coating film of the coating solution. This coating operation is
This can be carried out by using conventional coating means such as a doctor blade, roll coater, knife coater, etc.

After the coating film is formed, the coating film is dried to complete the formation of the phosphor layer on the support. The thickness of the phosphor layer varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, the mixing ratio of the binder and the phosphor, etc., but is usually between 20 gm and 1 m.
Let it be m. However, the thickness of this layer is preferably 50 to 500 Bm.

In addition, the phosphor layer does not necessarily need to be formed by directly applying a coating liquid onto the support as described in 1.
Separately, a phosphor layer is formed by applying a coating liquid onto a sheet such as a glass plate, metal plate, or plastic sheet and drying, and then this is pressed onto a support, or by using an adhesive. The support and the phosphor layer may be bonded together.

Note that the phosphor layer may be one layer, or two or more layers may be laminated. In the case of lamination, at least one layer contains the above-mentioned divalent europium-activated alkaline earth metal fluoride halide phosphor. Any layer may be used as long as it contains it. Further, in both the case of a single layer and a laminated layer, a different type of stimulable phosphor can be used together with the above phosphor.

The support can be arbitrarily selected from various materials used as supports for intensifying screens in conventional radiography or materials known as supports for radiation image storage panels. Examples of such materials include films of plastic substances such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate, metal sheets such as aluminum foil, aluminum alloy foil, regular paper, baryta paper, resin. Examples include coated paper, pigment paper containing pigments such as titanium dioxide, and paper sized with polyvinyl alcohol.

However, in consideration of the characteristics and handling of the radiation image storage panel as an information recording material, a particularly preferred material for the support in the present invention is a plastic film.

A light-absorbing substance such as carbon blur 2 may be incorporated into this plastic film.

Alternatively, a light-reflecting substance such as titanium dioxide may be kneaded into the support. It is a support.

In known radiation image conversion panels, a phosphor layer is provided in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymeric substance such as gelatin is coated on the surface of the support on the side to be coated to form an adhesion imparting layer, or a light reflective layer made of a light reflective substance such as titanium dioxide, or a light absorbing substance such as carbon black. The support used in the present invention, which is also provided with a light absorption layer, can also be provided with these various layers.

Furthermore, as described in Japanese Patent Application Laid-Open No. 58-200200, in order to improve the sharpness of the obtained image, a phosphor layer of the camellia-faced C-sided body on the phosphor layer side of the camellia body is added. When the side surface is provided with an adhesion-imparting layer, a light-reflecting layer, a light-absorbing layer, etc., fine irregularities may be uniformly formed on the surface (meaning the surface).

In a typical radiation image conversion panel, a transparent protective film for physically and chemically protecting the phosphor layer is provided on the surface of the phosphor layer on the side opposite to the side in contact with the support. Such a transparent protective film is preferably provided also in the radiation image conversion panel of the present invention.

The transparent protective film may be made of a transparent material such as a cellulose derivative such as cellulose acetate or nitrocellulose; or a synthetic polymeric material such as polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, or vinyl chloride Φ vinyl acetate copolymer. It can be formed by coating the surface of the phosphor layer with a solution prepared by dissolving a polymeric substance in an appropriate solvent. Alternatively, it can also be formed by a method such as adhering a transparent thin film separately formed from polyethylene terephthalate, polyethylene, polyvinylidene chloride, polyamide, etc. to the surface of the phosphor layer using a suitable adhesive. The thickness of the transparent protective film formed in this way is
Preferably it is about 3 to 20 pm.

In addition, JP-A-55-163500, JP-A-57-
As described in Japanese Patent No. 96300 and the like, the radiation image conversion panel of the present invention may be colored with a colorant, and the sharpness of the image obtained can be improved by coloring. Further, as described in Japanese Patent Application Laid-Open No. 55-146447, the radiation image conversion panel of the present invention may have white powder dispersed in its phosphor layer for the same purpose.

Examples and comparative examples of the present invention are described below. However, each of these does not limit the present invention.

[Example 1] 175.34 g of barium fluoride (BaF2), 333.18 g of barium bromide (BaBr2.2H20), and 0.392 g of europium bromide (EuBr:i) were added to 500 cc of distilled water (H2O), The mixture was mixed to form a suspension. This suspension was dried under reduced pressure at 60° C. for 3 hours, and then further vacuum dried at 150° C. for 3 hours. After finely pulverizing the dried product using a mortar, 100g of the pulverized product
0.218 g of indium fluoride (InF3) and 0.044 g of sodium bromide (NaBr) were added and mixed.
A homogeneous mixture was obtained.

Next, the obtained phosphor raw material mixture was filled into an alumina crucible, which was then placed in a high-temperature electric furnace and fired. Calcination was carried out at 900 °C in a carbon dioxide atmosphere containing -carbon oxide.
It was carried out for 1.5 hours at a temperature of .degree. After the firing was completed, the fired product was taken out of the furnace and cooled. The obtained fired product is pulverized to obtain a powdered divalent europium-activated barium fluoride bromide phosphor (BaF) containing indium fluoride.
B r 110.001 NaB r・0. o03 I
nF3: o, o.

05E u needle) was obtained.

In addition, in the production of the above phosphor, the amount of indium fluoride added is 10" to 4 x 10-1 mole of BaFBr.
Various divalent europium-activated barium fluoride bromide phosphors with different indium fluoride contents were obtained by changing the content within a molar range.

Next, a radiation image conversion panel was manufactured using each of the obtained phosphors in the following manner.

Methyl ethyl ketone was added to a mixture of phosphor particles and linear polyester resin, and nitrocellulose with a degree of nitrification of 11.5% was further added to prepare a dispersion containing phosphor particles in a dispersed state. In this dispersion, tricresyl phosphate,
After adding n-butanol and methyl ethyl ketone, stir and mix thoroughly using a propeller mixer.
The phosphor particles are uniformly dispersed, the mixing ratio of the binder and the phosphor particles is 1 = 20, and the viscosity is 25 to 35 PS (25°C
) was prepared.

This coating solution was applied to a titanium dioxide-mixed polyethylene terephthalate sheet (support material,
Thickness: 250 g, m), then put the support with the coated film into a dryer, and gradually raise the temperature inside the dryer from 25°C to 100°C to dry the coated film. Drying was performed.

In this way, a phosphor layer with a layer thickness of 2001 Lm was formed on the support.

Then, by placing and adhering a polyethylene terephthalate transparent film (thickness: 12ILm, coated with a polyester adhesive) with the adhesive layer side facing down, a transparent protective film is formed on top of this phosphor layer. A radiation image storage panel consisting of a support, a phosphor layer and a transparent protective film was manufactured.

[Comparative Example 1] In Example 1, a powdered bivalent product was obtained by performing the same operation as in Example 1 except that only sodium bromide was added without adding indium fluoride to 100 g of the pulverized material. Europium-activated barium fluoride bromide phosphor (
B a FB r 110.001 N a B r :
0.0005E u ”) was obtained.

v1p+,%s-噌1ita↓1J-a44--J-
A radiation image storage panel composed of a support, a phosphor layer and a transparent protective film was produced by a method similar to the method described in 1.

[Example 2] In Example 1, in addition to indium fluoride and sodium bromide, silicon dioxide (Si02) was added to 100 g of the pulverized material.
A powdered divalent europium-activated barium fluoride bromide phosphor containing indium fluoride and silicon dioxide (B aFB r-0,001N
aBr 110.003I aFB・0.004 S
i02:0.0005Eu'') was obtained.

In addition, various divalent europium-activated barium fluoride bromide phosphors having different contents of indium fluoride were obtained by performing the same operations as in Example 1 in producing the above phosphors.

Next, using each of the obtained phosphor particles, a radiation image conversion panel consisting of a support, a phosphor layer, and a transparent protective film was manufactured in the same manner as in Example 1.

[Comparative Example 2] By performing the same operation as in Example 1 except that only sodium bromide and silicon dioxide were added to 100 g of the pulverized material without adding indium fluoride, a powdery product was obtained. Divalent europium-activated barium fluoride bromide phosphor (BaFB r-0,001NaB
r・0.004 S i02: 0.00
05E u'') was obtained.

Next, using the obtained phosphor particles, a radiation image storage panel consisting of a support, a phosphor layer, and a transparent protective film was manufactured in the same manner as in Example 1.

Next, each of the radiation image conversion panels obtained in Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2 was evaluated by the afterimage characteristic test described below.

After irradiating the radiation image conversion panel with X-rays with a tube voltage of 80 KVp, He-Ne laser light (wavelength: 632.8 nm)
The stimulated luminescence amount (initial luminescence amount) when excited by scanning at a scanning density of 101 Lne/mmc7) was measured. Further, this panel was light-extinguished for about 3 minutes using a white fluorescent lamp, and then left at a temperature of 35° C. for 3 hours, and then excited again with He-Ne laser light to measure the amount of stimulated luminescence (residual luminescence amount).

The afterimage characteristics were evaluated using the ratio of [residual luminescence amount/initial luminescence amount] as the relative luminescence amount.

The results obtained are summarized and shown in graph form in FIG.

Figure 1 shows: - BaFBr fist 0. OOI NaBr@bI
nF3: 0.0005E u2+ phosphor-containing T6 radiation 1 image conversion panel and BaFBreo
, 001 N aBr* b I aFB
Life 0.004 S i02: 0.000
Regarding the radiation image conversion panel containing 5Eu 2+ phosphor, the content of InF3 (b value) is taken on the horizontal axis,
This is a graph (curves 1 and 2, respectively) in which the vertical axis represents the relative luminescence amount.

As is clear from FIG. 1, the BaFB r · of the present invention
0.001 NaB r @bI aFB :0.00
05E ubI aFB・0.004 S i02:
In any radiation image storage panel containing 0.0005Eu" phosphor, the b value is 3 x 10-'≦b≦
When the Si
The O2-doped phosphor showed a significant reduction in residual luminescence.

[Example 3] In Example 1, oxidation was carried out in the same manner as in Example 1 except that 0.353 g of indium oxide (Inzo3) was added to 100 g of the pulverized material instead of indium fluoride. Powdered divalent europium-activated barium fluoride bromide phosphor containing indium (B a
FB r @0.001N aB r 11G, 003
In 203 : 0.0005E u2+) was obtained.

In addition, various divalent europium-activated barium fluoride bromide phosphors having different contents of indium oxide were obtained by performing the same operations as in Example 1 in producing the above phosphors.

The support, the phosphor layer and the transparent film were removed using a method similar to that of Ukei.
A radiation image conversion panel constructed from a membrane was manufactured.

[Example 4] Indium oxide was produced by performing the same operation as in Example 3 except that 0.1 g of silicon dioxide was added to 100 g of the pulverized material in addition to indium oxide and sodium bromide. and powdered divalent europium-activated barium fluoride bromide phosphor containing silicon dioxide (BaFB r ・0.001 NaBr
*0.003 I n203110.004 S i
02: 0.0005E u'') was obtained.

In addition, various divalent europium-activated barium fluoride bromide phosphors having different contents of indium oxide were obtained by performing the same operations as in Example 3 in producing the above phosphors.

Next, using each of the obtained phosphor particles, a radiation image conversion panel consisting of a support, a phosphor layer, and a transparent protective film was manufactured in the same manner as in Example 1.

Next, each of the radiation image storage panels obtained in Example 3 and Example 4 was evaluated by the above-mentioned afterimage characteristic test. The results obtained are summarized and shown in the form of a graph in FIG.

Figure 2 shows B a F B r * 0.001 N
a B r * b I n 203: 0.0005
E u2′) A radiation image conversion panel containing a phosphor and B a F B r ・0.001 N a B r
* b I n 203 @ 0.004 S i
O2: A graph showing the content of In 203 (b value) on the horizontal axis and the relative luminescence amount on the vertical axis for a radiation image conversion panel containing 0.0005Eu2+ phosphor (curves 1 and 2, respectively) It is.

As is clear from FIG. 2, the BaFB r · of the present invention
0.001 NaB r * b I n203:0.
0005Eu meter phosphor or B a F Br −
0,001N aBr * b I n203 *0
．． 004 S i 02 : In any radiation image storage panel containing 0.000 SEu or phosphor, b
When the value was in the range of 3XlO'≦b≦2×1O4, the amount of residual light emission of the phosphor was reduced and the afterimage characteristics were improved. In particular, the latter 5i02-doped phosphor showed a significant decrease in residual luminescence.

[Brief explanation of the drawing]

Figure 1 shows B a F B r IIO,001N a
B r 11bI n F 3 : 0.0005E
Radiation image conversion panel containing u2+ phosphor and B
aFB r eO,001N aB r・b I n
F3 *o, oo4S 1c)2: 0.0005Eu
"Regarding a radiation image conversion panel containing a phosphor. This is a graph (curves 1 and 2, respectively) showing the relationship between the content (b value) of InF3 and the relative luminescence amount. FIG. B r * 0.001N
aBr*bIn203: 0.0005
A radiation image conversion panel containing E u” phosphor and B a F B r 110. (I01N aB r
@b I n203110.004 S i 02:
2 is a graph (curves 1 and 2, respectively) showing the relationship between In2O3 content (b value) and relative luminescence amount for a radiation image conversion panel containing 0.0005Eu8 phosphor.

Claims (14)

[Claims] 1. Composition formula (I): M^IIIFX・a_NaX'・b_A:x_Eu^2
^+...(I) (However, M^III is at least one kind of alkaline earth metal selected from the group consisting of Ba, Ca, and Sr; X and X' are both composed of Cl, Br, and I. At least one halogen selected from the group; A
is at least one selected from the group consisting of InF_3 and In_2O_3: and a, b and x are respectively 0<a≦2.0, 3×10^-^4≦b≦2×
10^-^2 and 0<x≦0.2) A divalent europium-activated alkaline earth metal fluoride halide phosphor. 2. b in compositional formula (I) is 6×10^-^3≦
The phosphor according to claim 1, wherein the numerical value is in the range of b≦10^-^2. 3. a in compositional formula (I) is 10^-^5≦a≦
The phosphor according to claim 1, wherein the phosphor has a numerical value in the range of 5×10^-^5. 4. The phosphor according to claim 1, wherein M^III in the compositional formula (I) is Ba. 5. The phosphor according to claim 1, wherein X in compositional formula (I) is at least one of Br and I. 6. The phosphor according to claim 1, wherein X' in compositional formula (I) is Br. 7. x in compositional formula (I) is 10^-^5≦x≦
The phosphor according to claim 1, wherein the phosphor has a numerical value in the range of 10^-^1. 8. In a radiation image storage panel substantially composed of a support and a stimulable phosphor layer provided thereon, the stimulable phosphor layer is a divalent phosphor represented by the following compositional formula (I). A radiation image conversion panel comprising a europium-activated alkaline earth metal fluorohalide phosphor. Composition formula (I): M^IIFX・aNaX'・bA:xEu^2^+...
・(I) (However, M^II is at least one kind of alkaline earth metal selected from the group consisting of Ba, Ca and Sr; X and x' are both selected from the group consisting of Cl, Br and I. At least one kind of halogen; A is at least one kind selected from the group consisting of InF_3 and In_2O_3; and a, b and x are respectively 0<a≦2.0, 3×10^-^4≦b≦ 2×1
0^-^2 and 0<x≦0.2) 9. b in compositional formula (I) is 6×10^-^2≦b
The radiation image conversion panel according to claim 8, characterized in that the value is in the range of ≦10^-^2. 10. a in compositional formula (I) is 10^-^5≦a≦
9. The radiation image conversion panel according to claim 8, wherein the value is in the range of 5×10^-^1. 11. 9. The radiation image storage panel according to claim 8, wherein M^III in compositional formula (I) is Ba. 12. 9. The radiation image storage panel according to claim 8, wherein x in compositional formula (I) is at least one of Br and I. 13. 9. The radiation image storage panel according to claim 8, wherein x' in compositional formula (I) is Br. 14. x in compositional formula (I) is 10^-^5≦x≦
9. The radiation image conversion panel according to claim 8, wherein the value is in the range of 10^-^1.