JP2000192033A - Preparation of rare earth-activated, alkaline earth metal fluoride halide-based stimulable phosphor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phosphor with high sensitivity and erasability by adding an inorganic fluoride salt, a rare earth element, an alkali metal halide, etc., at a specified temperature to a mother liquor prepared from a water solution of Ba halide and a water solution of a halide or the like of another alkaline earth metal or an alkali metal to precipitate a precursor and separating and baking the precursor. SOLUTION: A water solution of an inorganic fluoride salt, a water-soluble Ln compound, and a halide or the like of M' or M" is added, at 20-100 deg.C under stirring, to a mother liquor which is prepared from a water solution of BaX2 and a water solution of a halide, a nitrate, or the like of M" or M', each solution being prepared in a specified concentration, to form a precipitate of phosphor precursor crystals, and the precipitate is separated and baked to give a stimulable phosphor represented by the formula, which has a particle size Dm of 1.0-2.0 μm, a standard deviation of particle size distribution ρ/Dm of 50% or lower, and an aspect ratio of 1.0-2.0. In the formula, M" is Sr or Ca; M' is K, Na, or the like; X is Cl, Br, or I; Ln is Ce, Eu, or the like, 0<=x<=0.5; 0<=y<=0.5; and 0<z<=0.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor.

[0002]

2. Description of the Related Art As an alternative to the conventional radiographic method, there is known a radiation image recording / reproducing method using a stimulable phosphor as described in, for example, JP-A-55-12145. This method uses a radiation image conversion panel (a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor of the panel. By absorbing the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time series manner, the radiation energy stored in the stimulable phosphor is absorbed by the body. The fluorescent light is emitted (stimulated emission light), the fluorescent light is read photoelectrically to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal. . After the reading of the panel is completed, after the remaining image is deleted, the panel is prepared for the next photographing. That is, the radiation image conversion panel can be used repeatedly.

According to the above-described radiographic image recording / reproducing method, a radiographic image having a much smaller amount of exposure and a richer amount of information than a radiographic method using a combination of a conventional radiographic film and an intensifying screen. There is an advantage that can be obtained. Further, in the conventional radiographic method, a radiographic film is consumed for each photographing, whereas in the radiographic image conversion method, the radiographic image conversion panel can be used repeatedly, thereby conserving resources and saving economy. It is also advantageous in terms of efficiency.

[0004] A stimulable phosphor is a phosphor that emits stimulable light when irradiated with excitation light after being irradiated with radiation. However, in practice, the stimulable phosphor has a wavelength within a range of 400 to 900 nm due to excitation light having a wavelength of 400 to 900 nm. Is generally used. Examples of stimulable phosphors conventionally used in radiation image conversion panels include rare earth-activated alkaline earth metal fluorinated halide-based phosphors. The radiation image conversion panel used in the radiation image recording / reproducing method has, as a basic structure, a support and a stimulable phosphor layer provided on the surface of the support. However, when the stimulable phosphor layer is self-supporting, a support is not necessarily required. The stimulable phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. However, there is also known a stimulable phosphor layer which does not include a binder formed by a vapor deposition method or a sintering method and is composed of only an aggregate of the stimulable phosphor. Further, there is known a radiation image conversion panel having a stimulable phosphor layer in which a polymer substance is impregnated in a gap between stimulable phosphor aggregates. In any of these stimulable phosphor layers, the stimulable phosphor has a property of exhibiting stimulable emission when irradiated with excitation light after absorbing radiation such as X-rays. Radiation transmitted through the subject or emitted from the subject is absorbed in the stimulable phosphor layer of the radiation image conversion panel by an amount of energy proportional to the radiation dose, and the panel displays the radiation image of the subject or the subject. It is formed as an image of accumulated radiation energy. This accumulated image can be emitted as stimulated emission light by irradiating the excitation light, and the accumulated image of radiation energy is imaged by photoelectrically reading the stimulated emission light and converting it into an electric signal. It is possible to do.

The surface of the stimulable phosphor layer (the surface not facing the support) is usually provided with a protective film such as a polymer film or an inorganic vapor-deposited film. The phosphor layer is protected from chemical alteration or physical impact.

The rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor has excellent sensitivity and, when used as a radiation image conversion panel, produces a radiation-reproduced image with high sharpness. It can be called an excellent stimulable phosphor. However, as the radiation image recording / reproducing method has been put to practical use, there has been an increasing demand for further improving the performance of the stimulable phosphor. Then, when the particle shapes of the rare earth activated alkaline earth metal fluorohalide-based stimulable phosphors used so far were examined, they were found to be composed of plate-like particles. Conventionally known methods for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor include a starting compound alkaline earth metal fluoride, an alkaline earth metal halide other than fluoride, and a rare earth element. A halide, ammonium fluoride, etc. are mixed together in a dry system or suspended in an aqueous medium and mixed, and then, if necessary, a sintering inhibitor is added, followed by calcination and pulverization. Process. Therefore, in the conventional production method, the pulverization step after firing is substantially essential, and the particles of the rare earth activated alkaline earth metal fluoride halide stimulable phosphor thus obtained are mostly contained. Were plate-like particles (hereinafter sometimes simply referred to as “plate-like phosphor”).

However, in the stimulable phosphor layer obtained by mixing such a plate-shaped phosphor with a binder resin solution, coating the mixture on a support, and drying, the plate-shaped phosphor is seen in FIG. As a result, the plate-like phosphor surface and the support plane tend to be arranged in parallel. When a radiation image is stored in a radiation image conversion panel having a stimulable phosphor layer on which a plate-like phosphor is arranged as described above, and the excitation light is irradiated, the excitation light and the generated stimulable luminescence are generated in a lateral direction ( This tends to spread in a direction parallel to the plane of the support (see the horizontal arrow in FIG. 1), which causes a problem that the sharpness of the obtained reconstructed radiation image is easily reduced.

In order to suppress the decrease in the sharpness of a radiation reproduced image in the radiation image recording / reproducing method as described above, a substantially cubic stimulable phosphor disclosed in JP-A-62-86086 is used. It is conceivable to use particles.
However, the method for producing the substantially cubic stimulable phosphor particles disclosed in the above publication does not have sufficient reproducibility for industrial use.

Further, Japanese Patent Application Laid-Open No. 7-233369,
Japanese Patent Application No. 6-315573 and Japanese Patent Application Laid-Open No. 10-19.
No. 5431 discloses a method for producing a tetrahedral rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor (hereinafter sometimes simply referred to as “phosphor”) in which the particle shape and the particle aspect ratio are controlled. It is shown. Radiation image conversion having a stimulable phosphor layer on which a tetradecahedral rare earth activated alkaline earth metal fluoride halide stimulable phosphor (hereinafter may be simply referred to as “tetrahedral phosphor”) is disposed. In the panel, as shown in FIG. 2, in the stimulable phosphor layer,
Since the tetradecahedral phosphor exhibits an array with less directivity, undesired spread of the excitation light and the stimulated emission light in the lateral direction is reduced, and the sharpness of the obtained radiation reproduction image is improved. Although the emission characteristics, particularly sharpness, of the phosphor obtained by the manufacturing method disclosed in the above publication are extremely high, further improvement in sensitivity and erasing characteristics when used in a radiation image recording / reproducing method has been desired. .

[0010]

According to the present invention, when used in a radiation image recording / reproducing method, extremely high sharpness is obtained and high image quality is obtained, and other light emitting characteristics, particularly sensitivity and erasing characteristics, are not improved. An object of the present invention is to provide a method for producing a high rare earth activated alkaline earth metal fluoride halide stimulable phosphor.

[0011]

The above object is achieved by the present invention described below. That is, the present invention provides: <1> Basic composition formula (I): Ba _1-x M ^II _x FX: y M ^I , zLn (I) [where M ^II is selected from the group consisting of Sr and Ca at least one rare earth metal, M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and σ / Dm when the standard deviation of the particle size distribution is σ is in the range of 50% or less. A method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor having a ratio in the range of 1.0 to 2.0, wherein BaX ₂ ; x of the above-mentioned basic composition formula (I) When is not 0, further halides, nitrates, nitrites or acetates of M ^II ; when y in the above basic composition formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^I (However, excluding those components which are added simultaneously with the aqueous solution of the inorganic fluoride salt without any shortage), and the BaX ₂ concentration after dissolving them, wherein X is Cl or 2.5 mol / l for Br Torr, X is a mother liquid preparation step of preparing a reaction mother liquor is less than 5.0 mol / l in the case of I, the reaction mother liquid 2
While maintaining the temperature of 0 to 100 ° C., and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, a halide of M ^I, nitrate, an aqueous solution of nitrite or acetate and / or halides M ^II, aqueous nitrate, an aqueous solution of a nitrite or acetate, and the precipitate generating process of generating simultaneously added precipitate of phosphor precursor crystals, a precipitate of the phosphor precursor crystals And a baking step of baking the separated precipitate of the phosphor precursor crystal while avoiding sintering. This is a method for producing a depleted phosphor.

<2> Basic composition formula (I): Ba _1-x M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one selected from the group consisting of Sr and Ca Where M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and σ / Dm when the standard deviation of the particle size distribution is σ is in the range of 50% or less. A method for producing a rare earth activated alkaline earth metal fluoride halide stimulable phosphor having a ratio in the range of 1.0 to 2.0, comprising: BaX ₂ ; a water-soluble compound of Ln; Formula (I)
If x in formula (I) is not 0, then halide, nitrate, nitrite or acetate of M ^II ;
Halide of further M ^I in the case of y is not 0, nitrate, nitrite or acetate; (however, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salts are excluded.) The A reaction in which the BaX ₂ concentration is 2.5 mol / L or less when X is Cl or Br and 5.0 mol / L or less when X is I and mother liquor preparation step of preparing a mother liquor, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C., and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, halide M ^I ,nitrate,
Simultaneously with an aqueous solution of nitrite or acetate and / or an aqueous solution of halide, nitrate, nitrite or acetate of M ^II (except when both x and y in the above basic composition formula (I) are both 0) Adding a precipitate of the phosphor precursor crystal to form a precipitate, a separation step of separating the precipitate of the phosphor precursor crystal from an aqueous solution, and separating the precipitate of the separated phosphor precursor crystal. And a sintering step of sintering while avoiding sintering. A method for producing a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor.

<3> Basic composition formula (I): Ba _{1 -x} M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one selected from the group consisting of Sr and Ca Where M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and σ / Dm when the standard deviation of the particle size distribution is σ is in the range of 50% or less. A method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor, wherein the ratio is in the range of 1.0 to 2.0, wherein NH ₄ X; When is not 0, further halides, nitrates, nitrites or acetates of M ^II ; when y in the above basic composition formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^I (However, excluding those components which are added at the same time as the inorganic fluoride salt aqueous solution without any shortage), and having an NH ₄ X concentration of 4.5 mol after dissolving them. Prepare a reaction mother liquor that is less than And mother liquor preparation step, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C., and an aqueous solution of BaX ₂ thereto, and an aqueous solution of an inorganic fluoride salt, an aqueous solution containing a water-soluble compound of Ln,
Halides M ^I, nitrates, halides of nitrite or an aqueous solution of acetate and / or M ^II, nitrates,
A precipitate forming step of simultaneously adding an aqueous solution of nitrite or acetate and adding such that the ratio of fluorine of inorganic fluoride to BaX ₂ is kept constant to form a precipitate of phosphor precursor crystals; A separation step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, and a firing step of firing the separated precipitate of the phosphor precursor crystal while avoiding sintering, This is a method for producing an activated alkaline earth metal fluorohalide-based stimulable phosphor.

<4> Basic composition formula (I): Ba _1-x M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one selected from the group consisting of Sr and Ca Where M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and σ / Dm when the standard deviation of the particle size distribution is σ is in the range of 50% or less. A method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor having a ratio in the range of 1.0 to 2.0, comprising: a water-soluble compound of NH ₄ X; Ln; Composition formula (I)
When x in formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^II ;
An aqueous solution containing (however, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salts are excluded.); Halide of further M ^I when but not 0, nitrate, nitrite or acetate And a mother liquor preparation step of preparing a reaction mother liquor having an NH ₄ X concentration of 4.5 mol / l or less after dissolving them, and maintaining the reaction mother liquor at a temperature of 20 to 100 ° C. This is BaX ₂
An aqueous solution of the aqueous solution of an inorganic fluoride salt, an aqueous solution containing a water-soluble compound of Ln, M halide ^I, nitrate, an aqueous solution of nitrite or acetate and / or M
Simultaneously with an aqueous solution of a halide of ^II , a nitrate, a nitrite or an acetate (except when both x and y in the above basic composition formula (I) are both 0), and the fluorine of inorganic fluoride and BaX ₂ A precipitation generating step of adding a phosphor precursor crystal precipitate by adding so as to maintain a constant ratio, a separating step of separating the phosphor precursor crystal precipitate from an aqueous solution, A firing step of firing a precipitate of the body precursor crystal while avoiding sintering. A method for producing a rare earth-activated alkaline earth metal fluoride halide stimulable phosphor, comprising:

<5> When the amount of the precipitate of the phosphor precursor crystal finally obtained is N when the aqueous solution of the inorganic fluoride salt is added in the precipitate formation step, the phosphor formed during the addition is added. The addition rate was adjusted so that the amount of the precipitate of the precursor crystal was in the range of 0.001 N / min to 10 N / min,
<1. An aqueous solution of an inorganic fluoride salt is added.
> Or <2>, a method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor.

<6> At the time of adding the aqueous solution of the inorganic fluoride salt and the aqueous solution of BaX ₂ in the precipitate forming step, the amount of the precipitate of the phosphor precursor crystals finally obtained is defined as N. The addition rate is adjusted so that the amount of the precipitate of the phosphor precursor crystals generated in the above ranges from 0.001 N / min to 10 N / min.
<3> The method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor according to <3> or <4>, wherein an aqueous solution of aX ₂ is added.

<7> The rare earth activated alkaline earth metal fluoride according to any one of <1> to <6>, wherein the inorganic fluoride salt is ammonium fluoride or an alkali metal fluoride. This is a method for producing a halide stimulable phosphor.

<8> In the precipitate formation step, the addition of an aqueous solution other than the aqueous solution of the inorganic fluoride salt and the aqueous solution of BaX ₂ to be added simultaneously with the aqueous solution of the inorganic fluoride salt is performed continuously during the addition time. <1> The method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor according to any one of <1> to <7>, wherein the phosphor is changed so as to be changed intermittently or intermittently. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Rare earth activated alkaline earth metal fluorinated halide stimulable phosphor First, the rare earth activated alkaline earth metal fluorinated halide stimulable phosphor which is a production object of the production method of the present invention will be described. Rare earth activated alkaline earth metal fluorohalide stimulable phosphor of the present invention, the basic formula _{(I): Ba 1-x} M II x FX: y M I, zLn ··· (I) [ where , M ^II represents at least one alkaline earth metal selected from the group consisting of Sr and Ca, M ^I represents Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. ].

The rare earth activated alkaline earth metal fluoride halide stimulable phosphor represented by the above basic composition formula (I) usually has an aspect ratio in the range of 1.0 to 5.0. The rare earth activated alkaline earth metal fluoride halide stimulable phosphor of the present invention has a particle aspect ratio of 1.0.
~ 2.0 (more preferably 1.0 ~ 1.5), the median diameter (Dm) of the particle size is 1 ~ 10 m
(More preferably 2 to 7 μm), and σ / Dm is 50 when the standard deviation of the particle size distribution is σ.
% (More preferably 40 or less). Further, as the shape of the particles, there are a rectangular parallelepiped type, a regular hexahedron type, a regular octahedral type, an intermediate polyhedral type thereof, a tetrahedral type, and the like, and a tetrahedral type is preferable, but the particle aspect ratio, particle size and particle size distribution are preferable. If the condition is satisfied, the effects of the present invention can be achieved without being necessarily limited to the tetrahedral type.

The rare earth activated alkaline earth metal fluoride halide stimulable phosphor of the present invention can be advantageously used as a stimulable phosphor material for forming a phosphor layer of a radiation image conversion panel. it can.

Manufacturing Method The rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor of the present invention is manufactured by the following four manufacturing methods (A) to (D).

(A) BaX ₂ ; when x in the above-mentioned basic composition formula (I) is not 0, a halide, nitrate, nitrite or acetate of M ^II ; halide of further M ^I when not, nitrate, nitrite or acetate; (. However, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salt, excluding) be an aqueous solution containing And a reaction mother liquor having a BaX ₂ concentration of 2.5 mol / liter or less when X is Cl or Br and 5.0 mol / liter or less when X is I. and mother liquor preparation step, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C., and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, M ^I halides, nitrates,
A precipitate forming step of simultaneously adding an aqueous solution of nitrite or acetate and / or an aqueous solution of a halide, nitrate, nitrite or acetate of M ^II to obtain a precipitate of a phosphor precursor crystal; A rare earth activated alkali, comprising: a separation step of separating a precipitate of the body precursor crystal from the aqueous solution; and a firing step of firing the separated precipitate of the phosphor precursor crystal while avoiding sintering. A method for producing an earth metal fluorohalide-based stimulable phosphor.

(B) BaX ₂ ; a water-soluble compound of Ln; when x in the above basic composition formula (I) is not 0, M ^II
Halides, nitrates, nitrites or acetates of the formula: When y in the above basic composition formula (I) is not 0, M ^I
Halides, nitrates, nitrites or acetates of:
(However, among these components, the components which are added simultaneously with the aqueous solution of the inorganic fluoride salt are excluded), and the BaX ₂ concentration after dissolving them is such that X is Cl or Br. 2.5 mol / liter or less, X
In the case where is I, a mother liquor preparation step of preparing a reaction mother liquor of 5.0 mol / l or less;
While maintaining the temperature of ° C., and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, a halide of M ^I, nitrate, nitrite or acetate solution and / or M ^II An aqueous solution of a halide, nitrate, nitrite or acetate (except when both x and y in the above basic composition formula (I) are both 0) is simultaneously added to obtain a precipitate of phosphor precursor crystals. A precipitate generation step;
A separation step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, the separated precipitate of the phosphor precursor crystal,
A method for producing a rare earth-activated alkaline earth metal fluoride halide stimulable phosphor, comprising: a firing step of firing while avoiding sintering.

(C) NH ₄ X: When x in the above formula (I) is not 0, further halides of M ^II , nitrates,
Nitrite or acetate; y halides more M ^I when not 0 the above composition formula (I), the nitrate, nitrite or acetate; (however, among these components, an aqueous solution of an inorganic fluoride salt A mother liquor preparation step of preparing a reaction mother liquor which is an aqueous solution containing an aqueous solution containing at the same time, and having a NH ₄ X concentration of 4.5 mol / liter or less after dissolution. 20-1 reaction mother liquor
While maintaining the temperature at 00 ° C., and an aqueous solution of BaX ₂ thereto, and an aqueous solution of an inorganic fluoride salt, an aqueous solution containing a water-soluble compound of Ln, a halide of M ^I, nitrate, nitrite or acetate An aqueous solution and / or an aqueous solution of a halide, nitrate, nitrite or acetate of M ^II are added simultaneously and so as to keep the ratio of inorganic fluoride fluoride to BaX ₂ constant, and the phosphor precursor crystal is added. A precipitate forming step of obtaining a precipitate of the above, a separating step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, and a firing step of firing the separated precipitate of the phosphor precursor crystal while avoiding sintering. And a process for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor.

(D) NH ₄ X; a water-soluble compound of Ln; when x in the above formula (I) is not 0, further a halide, nitrate, nitrite or acetate of M ^II ; y is a halide further M ^I when non-zero), nitrate, nitrite or acetate; (however, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salts are excluded). And an aqueous solution containing
A mother liquor preparation step of preparing a reaction mother liquor having an NH ₄ X concentration of 4.5 mol / l or less after dissolving them, and adding BaX _{2 to} the reaction mother liquor while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C. Aqueous solution, an aqueous solution of an inorganic fluoride salt, Ln
An aqueous solution containing a water-soluble compounds, halides of M ^I, nitrate, an aqueous solution of nitrite or acetate and /
Or an aqueous solution of a halide, nitrate, nitrite or acetate of M ^II (except when both x and y in the above-mentioned basic composition formula (I) are both 0), and at the same time, fluorine of inorganic fluoride and BaX _A precipitate generating step of obtaining a precipitate of the phosphor precursor crystal by adding so as to maintain the ratio of ₂ constant, a separation step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, A method for producing a rare earth-activated alkaline earth metal fluoride halide stimulable phosphor, comprising: a firing step of firing a precipitate of a phosphor precursor crystal while avoiding sintering.

In the present invention, "aqueous solution" means
"Solute" refers to a substance dissolved by "aqueous medium". The term “aqueous medium” is a concept that includes not only water, but also a liquid having a high affinity for water (for example, alcohol or the like) alone or a mixture of a plurality of them, or a mixture of these and water. Of these, water is most preferred. Therefore, the term “aqueous solution” in the present invention is a concept including all the solutions prepared by the “aqueous medium” of the present invention, and it is most preferable to use water as the “aqueous medium”. On the other hand, the “solute” is appropriately selected depending on the type of the aqueous solution (raw material solution, reaction mother liquor, aqueous solution for addition, etc.).

In the production methods (A) to (D), the production method (B) is compared with the production method (A), and the production method (D) is compared with the production method (C). The difference is that the reaction mother liquor contains "Ln water-soluble compound" as a component, and that addition of an alkali metal salt and an alkaline earth metal salt is not essential in the step of forming a precipitate. The manufacturing methods (A) to (D) will be described separately for each process.

[Manufacturing methods (A) and (B)] i) Mother liquor preparation step First, a raw material compound other than a fluorine compound is dissolved using an aqueous medium to prepare a reaction mother liquor. That is, BaX ₂
(And a water-soluble compound of Ln in the production method (B)), and, if necessary, a halide, nitrate, nitrite or acetate of M ^II , and optionally M ^I.
Halide, nitrate, nitrite or acetate of
An aqueous medium (reaction mother liquor) in which these components are dissolved is prepared by thoroughly mixing and dissolving in an aqueous medium (provided that the components which are added simultaneously with the aqueous solution of the inorganic fluoride salt without any shortage). except.). At this time, when X is Cl or Br, BaX ₂ concentration is not more than 2.5 mol / l, and when X is I, BaX ₂ concentration is not more than 5.0 mol / l. Adjust the quantitative ratio between ₂ and the aqueous solvent. If desired, a small amount of acid, ammonia, water-soluble polymer, water-insoluble metal oxide fine particles, or the like may be added to the reaction mother liquor, if desired.

Ii) Precipitate formation step The above-obtained reaction mother liquor is maintained at 20 to 100 ° C, preferably 40 to 80 ° C, and stirred. And an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, a halide of M ^I, nitrates, halides of nitrite or an aqueous solution of acetate and / or M ^II, nitrates, nitrites or An aqueous solution of acetate (in the production method (B), x and y of the above-mentioned basic composition formula (I))
) Are preferably added simultaneously using a precision pump to obtain a precipitate of phosphor precursor crystals. As inorganic fluoride salts,
Ammonium fluoride, fluorides of alkali metals, fluorides of alkaline earth metals, fluorides of transition metals, hydrofluoric acid, and the like. Among them, in terms of solubility, emission characteristics, and pH change during the reaction, Ammonium and alkali metal fluorides are preferred.

When the amount of the precipitate of the phosphor precursor crystals finally obtained is N when the aqueous solution of the inorganic fluoride salt is added, the amount of the precipitate of the phosphor precursor crystals formed during the addition is defined as N. Is adjusted within a range of 0.001 N / min to 10 N / min (more preferably, a range of 0.01 N / min to 1.0 N / min), and an aqueous solution of an inorganic fluoride salt is added. Is preferred. If the addition speed is higher than the above, the phosphor precursor Dm may be 1 μm or less, or the particle aspect ratio may be 2 or more. If the addition speed is lower than the above, the phosphor precursor Dm may be 10 m. The above cases are not preferable. In order to precisely adjust the addition rate, it is preferable to add by a precision pump (for example, a precision cylinder pump, a precision gear pump, a tube pump, a diaphragm pump). Furthermore, this addition is usually performed at a constant addition rate,
The addition rate is an n-order function (n = 1, 2,
3) It may change continuously or intermittently as an exponential function or a differential function. This addition is preferably carried out in the region where the stirring is particularly vigorous.

The rate of addition of the other aqueous solution to be added simultaneously with the aqueous solution of the inorganic fluoride salt is not limited, and the addition may be started and stopped during the addition of the aqueous solution of the inorganic fluoride salt. In particular, the addition of these other aqueous solutions, during the addition time,
It is preferable that the addition rate be changed continuously or intermittently in order to change the distribution of the additive in the matrix and improve the light emission characteristics. By adding each of these aqueous solutions to the reaction mother liquor, a phosphor precursor crystal of the rare earth activated alkaline earth metal fluorohalide stimulable phosphor represented by the above basic composition formula (I) precipitates.

Iii) Separation Step The precipitate of the phosphor precursor crystal obtained as described above is separated from the aqueous solution by separation means such as suction filtration, pressure filtration, and centrifugation. The separated precipitate of the phosphor precursor crystal is sufficiently washed with a lower alcohol such as methanol and dried.

Iv) Firing Step The separated precipitate of the phosphor precursor crystal is fired while avoiding sintering. As a method of avoiding sintering, for example, a sintering inhibitor consisting of a metal oxide fine powder such as alumina, silica, zirconia, titania, and magnesia is added to the phosphor precursor crystal and mixed, and the sintering is performed on the crystal surface. A method of baking the fine powder of the anti-sizing agent to uniformly adhere it is exemplified. The addition of the sintering inhibitor can be omitted by appropriately adjusting the firing conditions.

As a specific firing method, a phosphor precursor crystal having a fine powder of a sintering inhibitor attached to the surface thereof, if necessary, is placed in a heat-resistant container such as a quartz boat, an alumina boat, a quartz crucible, or an alumina crucible. Filling and placing in a furnace core such as an electric furnace. Firing temperature 400 ~ 13
The range of 00 ° C is preferable, and the range of 500 to 1000 ° C is more preferable. Firing time varies depending on the filling amount of the phosphor precursor crystal, the firing temperature and the unloading temperature,
Generally, 0.5 to 12 hours is appropriate. The firing atmosphere may be a neutral atmosphere such as a nitrogen gas atmosphere, an argon gas atmosphere, a weak reducing atmosphere such as a nitrogen gas atmosphere containing a small amount of hydrogen gas, a carbon dioxide atmosphere containing carbon monoxide, or a trace oxygen introducing atmosphere. Used.
By the above calcination, the desired rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor is obtained.

[Manufacturing methods (C) and (D)] i) Step of preparing mother liquor First, a raw material compound other than a fluorine compound is dissolved using an aqueous medium to prepare a reaction mother liquor. That is, NH ₄ X
(And a water-soluble compound of Ln in the production method (D)), and, if necessary, a halide, nitrate, nitrite or acetate of M ^II , and optionally M ^I.
Halide, nitrate, nitrite or acetate of
An aqueous medium (reaction mother liquor) in which these components are dissolved is prepared by thoroughly mixing and dissolving in an aqueous medium (provided that the components which are added simultaneously with the aqueous solution of the inorganic fluoride salt without any shortage). except.). At this time, the NH ₄ X concentration is 4.5 mol / liter or less, preferably 2.0 to 4.5.
Mol / l, more preferably 3.0 to 4.5 mol / l
The amount ratio of NH ₄ X and the aqueous solvent is adjusted so as to be 1 liter. If desired, a small amount of acid, ammonia, water-soluble polymer, water-insoluble metal oxide fine particles, or the like may be added to the reaction mother liquor, if desired.

Ii) Precipitate formation step The above-obtained reaction mother liquor is maintained at 20 to 100 ° C, preferably 40 to 80 ° C, and stirred. This is B
an aqueous solution of aX _2, and an aqueous solution of an inorganic fluoride salt, an aqueous solution containing a water-soluble compound of Ln, a halide of M ^II,
Nitrates, halides nitrite or an aqueous solution of acetate and / or M ^I, nitrate, in an aqueous solution of nitrite or acetate (production method (D) x and y are both 0 in the above basic composition formula (I) And the aqueous solution containing each component is preferably added simultaneously using a precision pump so as to maintain a constant ratio of fluorine of inorganic fluoride to BaX _2. To obtain a precipitate. Examples of the inorganic fluoride salt include ammonium fluoride, alkali metal fluoride, alkaline earth metal fluoride, transition metal fluoride, hydrofluoric acid, and the like.
Ammonium fluoride and fluorides of alkali metals are preferred from the viewpoints of luminescence characteristics and changes in pH during the reaction.

When adding an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ , where the amount of the precipitate of the phosphor precursor crystal finally obtained is N, the phosphor precursor crystal formed during the addition is formed. Amount of the precipitate is 0.001 N / min to 10 N
/ Min (more preferably 0.01 N / min to 1.0 N)
/ Min) and the aqueous solution of inorganic fluoride salt and the aqueous solution of BaX ₂ are preferably added. If the addition speed is higher than the above, the phosphor precursor Dm may be 1 μm or less, or the particle aspect ratio may be 2 or more. If the addition speed is lower than the above, the phosphor precursor Dm may be 10 m. The above cases are not preferable. In order to precisely adjust the addition rate, it is preferable to add by a precision pump (for example, a precision cylinder pump, a precision gear pump, a tube pump, a diaphragm pump). Further, this addition is usually performed at a constant addition rate, but the addition rate is continuously or intermittently n-order function (n = 1, 2, 3), exponential function, differential function with respect to the addition time. May be changed. This addition is preferably carried out in the region where the stirring is particularly vigorous.

[0039] The addition of inorganic fluoride other aqueous solution to be added simultaneously with the aqueous solution and the aqueous solution of BaX ₂ salts are not constrained addition rate, the addition during the addition of the aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ It only has to start and end.
In particular, the addition of these other aqueous solutions may be performed so that the addition rate changes continuously or intermittently during the addition time.
This is preferable in that the distribution of the additive in the base is changed to improve the light emission characteristics. By adding each of these aqueous solutions to the reaction mother liquor, a phosphor precursor crystal of the rare earth activated alkaline earth metal fluorohalide stimulable phosphor represented by the above basic composition formula (I) precipitates.

Iii) Separation Step and Firing Step The precipitate of the phosphor precursor crystal obtained as described above is separated from the aqueous solution by a separation step of separating the precipitate of the phosphor precursor crystal from the aqueous solution. The desired rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor is obtained through a firing step of firing while avoiding sintering. Details of the separation step and the firing step are the same as those in the manufacturing method (A).

Next, a method of manufacturing a radiation image conversion panel using the rare earth activated alkaline earth metal fluorinated halide stimulable phosphor obtained by the method of the present invention will be described.

The rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor obtained by the production method of the present invention (hereinafter sometimes simply referred to as “stimulable phosphor”) is:
It is included in the stimulable phosphor layer of the radiation image conversion panel. Usually, it comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. The stimulable phosphor layer may further contain another stimulable phosphor and / or an additive such as a colorant.

A method for manufacturing a radiation image conversion panel will be described by taking, as an example, a case where the stimulable phosphor layer is composed of a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state.

The stimulable phosphor layer can be formed on a support by the following known method. First, a stimulable phosphor and a binder are added to a solvent and mixed well to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in a binder solution. The mixing ratio between the binder and the stimulable phosphor in the coating solution varies depending on the intended characteristics of the radiation image conversion panel, the type of the stimulable phosphor, and the like. Is selected from the range of 1: 1 to 1: 100, especially 1: 8 to 1:40.
It is preferable to select from the range. Next, the coating solution containing the stimulable phosphor and the binder prepared as described above is uniformly applied to the surface of the support to form a coating film. This coating operation is performed by a normal coating means, for example,
It can be performed by using a doctor blade, a roll coater, a knife coater or the like.

The support can be arbitrarily selected from those conventionally known as materials for supports of radiation image conversion panels. In known radiation image conversion panels, photostimulation is used to enhance the bond between the support and the photostimulable phosphor layer or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymer material such as gelatin is applied to the surface of the support on which the conductive phosphor layer is provided to provide an adhesion-imparting layer, or a light-reflective layer made of a light-reflective material such as titanium dioxide, or carbon black. It is known to provide a light absorbing layer made of a light absorbing substance. The support used in the present invention can also be provided with these various layers, and the configuration thereof can be arbitrarily selected depending on the desired purpose and application of the radiation image storage panel. Further, as described in JP-A-58-200200, the surface of the support on the side of the stimulable phosphor layer (the stimulable phosphor When an adhesiveness-imparting layer, a light-reflecting layer, a light-absorbing layer, or the like is provided on the surface on the layer side, it means the surface), and fine irregularities may be formed.

After forming a coating film on the support as described above, the coating film is dried to form a stimulable phosphor layer on the support. The thickness of the stimulable phosphor layer varies depending on the intended properties of the radiation image storage panel, the type of the stimulable phosphor, the mixing ratio of the binder to the stimulable phosphor, and the like.
0 μm to 1 mm. The layer thickness is 50 to 500 μm
It is preferred that The stimulable phosphor layer does not necessarily need to be formed by directly applying the coating solution on the support as described above. For example, the stimulable phosphor layer may be separately applied on a sheet such as a glass plate, a metal plate, or a plastic sheet. After forming the phosphor layer by applying and drying the liquid, this is pressed onto the support, or even if the support and the stimulable phosphor layer are joined by using an adhesive or the like. Good.

As described above, a protective film is usually provided on the stimulable phosphor layer. The protective film is formed by applying a solution prepared by dissolving a transparent organic polymer substance such as a cellulose derivative or polymethyl methacrylate in an appropriate solvent onto the stimulable phosphor layer. An organic polymer film such as polyethylene terephthalate or a protective film forming sheet such as a transparent glass plate is separately formed and provided on the surface of the stimulable phosphor layer with an appropriate adhesive, or an inorganic compound. Those formed on the stimulable phosphor layer by vapor deposition or the like are used. Also, formed by a coating film of a fluorine-based resin soluble in an organic solvent,
It may be a protective film in which perfluoroolefin resin powder or silicone resin powder is dispersed and contained.

For the purpose of improving the sharpness of the obtained image, at least one of the layers constituting the radiation image conversion panel absorbs excitation light and does not absorb stimulated emission light. Coloring agent, or an independent colored intermediate layer may be provided.
-23400).

According to the above method, a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor obtained by the production method of the present invention and a binder containing and supporting the same in a dispersed state are obtained on the support. And a radiation image conversion panel provided with a stimulable phosphor layer comprising

[0050]

The present invention will be specifically described below with reference to examples. In Examples and Comparative Examples, “aqueous solution”
Means a general aqueous solution using only water as a medium, regardless of the concept in the present invention.

Example 1 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
Reaction mother liquor (BaBr ₂ concentration: 1200 ml of an aqueous solution of r ₂ (2.5 mol / l) and 1800 ml of water
1.0 mol / l) was placed in a 4 liter reactor. The reaction mother liquor in the reactor was kept at 60 ° C., and was provided with a mixing chamber having a volume of about 100 ml.
mm screw-type stirring blades,
m, and the reaction mother liquor was stirred to generate an upward flow from the mixing chamber.

An aqueous solution of ammonium fluoride (NH ₄ F) (1
0 mol / L) NH ₄ F diluted aqueous solution obtained by mixing 150 ml and water 150 ml, EuBr ₃ diluted aqueous solution obtained by mixing 7.5 mL of EuBr ₃ aqueous solution (0.2 mol / L) and 92.5 ml of water, CaBr ₂ aqueous solution (0.15
Mol / l) and 100 ml of an aqueous KBr solution (0.25 mol / l) were separately prepared. Using a separate precision cylinder pump, NH ₄ was added to the mixing chamber in the reaction mother liquor, which was kept warm under the above stirring.
In F dilute aqueous solution 6 ml / min addition rate EuBr ₃ dilute aqueous solution was added simultaneously with CaBr ₂ solution, and KBr solution respectively 1 ml / min addition rate, to produce a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. 1% by weight of ultrafine alumina powder was added to the obtained europium-activated barium fluorobromide crystal in order to prevent a change in particle shape due to sintering during firing and a change in particle size due to fusion between particles. The resulting mixture was mixed well with a mixer to uniformly adhere ultrafine alumina powder to the crystal surface. 100 g of this was filled in a quartz boat, and calcined at 850 ° C. for 2 hours in a nitrogen gas atmosphere using a tube furnace to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 C
a _0.01 FBr: 0.0003K.0.001Eu ²⁺ ) was obtained.

Example 2 NH ₄ was synthesized in order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide.
A reaction mother liquor consisting of 1780 ml of an aqueous Br solution (4.5 mol / l) and 220 ml of water (NH ₄ Br concentration of 4.
0 mol / l) was placed in a 4 liter volume reactor. The reaction mother liquor in this reactor was kept at 60 ° C., and was provided with a mixing chamber having a volume of about 100 ml and a diameter of 45 mm.
Was rotated at 500 rpm to stir the reaction mother liquor so as to generate an upward flow from the mixing chamber.

NH ₄ F aqueous solution (10 mol / l) 1
00ml, BaBr ₂ aqueous solution (2.5mol / L)
400 mL, 5 mL of EuBr ₃ aqueous solution (0.2 mol / L) and 95 mL of water mixed EuBr ₃ diluted aqueous solution, CaBr ₂ aqueous solution (0.1 mol / L) 10
0 ml and 100 ml of an aqueous KBr solution (0.25 mol / l) were separately prepared. Using a separate precision cylinder pump, an aqueous solution of BaBr ₂ was added at a rate of 8 ml / min to the mixing chamber in the reaction mother liquor, which was kept warm under the above stirring, at a rate of addition of NH ₄ F aqueous solution, EuBr ₃ diluted aqueous solution, CaBr ₂ aqueous solution and KBr aqueous solution were simultaneously added at an addition rate of 2 ml / min, respectively, to form a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
After vacuum drying at 0 ° C. for 4 hours, about 220 g of europium-activated barium fluorobromide crystals were obtained. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Example 3 Europium-activated fluorobromide
In order to synthesize a stimulable phosphor precursor of lithium, BaB
r_Two1200 ml of an aqueous solution (2.5 mol / l)
CaBr_Two・ 2H _Two3.54 g of O2 and 2.98 g of KBr
And a reaction mother liquor (BaBr) composed of 1800 ml of water_TwoDark
(The degree is 1.0 mol / liter)
I put it in a bowl. Keep the reaction mother liquor in this reactor at 60 ° C
And a mixing chamber with a volume of about 100 ml
A screw-type stirring blade having a diameter of 45 mm was used.
Rotate at 0 rpm to generate upward flow from the mixing chamber
The reaction mother liquor was stirred.

NH ₄ F aqueous solution (10 mol / l) 1
NH ₄ F diluted aqueous solution in which 50 ml and water 150 ml are mixed, KBr aqueous solution (0.25 mol / l) 100 m
EuBr ₃ mixed with 7.5 ml of an aqueous EuBr ₃ solution (0.2 mol / l) and 92.5 ml of water
_Three diluted aqueous solutions were separately prepared. Using a separate precision cylinder pump, the NH ₄ F diluted aqueous solution was added at a rate of 6 ml / min, and the EuBr ₃ diluted aqueous solution was added at a rate of 4 ml / min. Each was added simultaneously at the rate of addition to produce a precipitate.
However, the addition of the EuBr ₃ diluted aqueous solution was started 25 minutes after the start of the NH ₄ F diluted aqueous solution. This addition produced a precipitate. Keep warming and stirring after addition is complete.
The sediment was aged for a continuous time.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Example 4 Europium-activated fluorobromide
In order to synthesize a stimulable phosphor precursor of lithium, BaB
r_Two1200 ml of an aqueous solution (2.5 mol / l)
CaBr_Two・ 2H _Two3.54 g of O2 and 2.98 g of KBr
And a reaction mother liquor (BaBr) composed of 1800 ml of water_TwoDark
(The degree is 1.0 mol / liter)
I put it in a bowl. Keep the reaction mother liquor in this reactor at 60 ° C
And a mixing chamber with a volume of about 100 ml
A screw-type stirring blade having a diameter of 45 mm was used.
Rotate at 0 rpm to generate upward flow from the mixing chamber
The reaction mother liquor was stirred.

NH ₄ F aqueous solution (10 mol / l) 1
NH ₄ F diluted aqueous solution in which 50 ml and water 150 ml are mixed, KBr aqueous solution (0.25 mol / l) 100 m
EuBr ₃ mixed with 7.5 ml of an aqueous EuBr ₃ solution (0.2 mol / l) and 92.5 ml of water
_Three diluted aqueous solutions were separately prepared. Using a separate precision cylinder pump, the NH ₄ F diluted aqueous solution was added at a rate of 6 ml / min, and the EuBr ₃ diluted aqueous solution was added to the mixing chamber in the reaction mother liquor kept warm under the above stirring. It increases linearly with addition time t (minutes) υ = 0.
Each was added at the same time at an addition rate of 08 t, and a precipitate was formed. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Example 5 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
r ₂ aqueous solution (2.5 mol / l) and 1200 ml,
2.5 ml of EuBr ₃ (0.2 mol / l) and C
and aBr ₂ · 2H ₂ O3.54g, KBr2.98g
And 1800 ml of water (BaBr ₂ concentration: 1.0 mol / l) were charged into a 4 liter reactor. The reaction mother liquor in this reactor was kept at 60 ° C., and a screw-type stirring blade having a diameter of 45 mm provided with a mixing chamber having a volume of about 100 ml was used.
The reaction mother liquor was stirred at 0 rpm to generate an upward flow from the mixing chamber.

NH ₄ F aqueous solution (10 mol / l) 1
An NH ₄ F diluted aqueous solution obtained by mixing 50 ml of water and 150 ml of water, and a EuBr ₃ diluted aqueous solution obtained by mixing 5 ml of an EuBr ₃ aqueous solution (0.2 mol / liter) and 95 ml of water were separately prepared. Using a separate precision cylinder pump, the NH ₄ F diluted aqueous solution was added at a rate of 6 ml / min, and the EuBr ₃ diluted aqueous solution was added at a rate of 2 ml / min. Each was added simultaneously at the rate of addition to produce a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Example 6 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, NH _{4 was used.}
1780 ml of Br aqueous solution (4.5 mol / l)
A reaction mother liquor (NH ₄ Br concentration of 4.0 mol / l) composed of 2.5 ml of an aqueous solution of EuBr ₃ and 217.5 ml of water was placed in a 4 liter reactor. The reaction mother liquor in this reactor was kept warm at 60 ° C.
Using a screw-type stirring blade with a diameter of 45 mm provided with a mixing chamber of 50 ml, this was rotated at 500 rpm to stir the reaction mother liquor so as to generate an upward flow from the mixing chamber.

NH_FourF aqueous solution (10 mol / l) 1
00ml, BaBr_TwoAqueous solution (2.5 mol / L)
400ml, EuBr_ThreeAqueous solution (0.2 mol / l
E) EuBr mixed with 2.5 ml of water and 97.5 ml of water
_ThreeDilute aqueous solution, CaBr_TwoAqueous solution (0.1 mol / l
100 mL) and KBr aqueous solution (0.25 mol
Per liter) was separately prepared. These over
Separate purification solutions are added to the mixing chamber in the reaction mother liquor kept warm under stirring.
BaBr using a dense cylinder pump_Two8m aqueous solution
at an addition rate of 1 / min, NH_FourF aqueous solution, EuBr_ThreeDilution
Aqueous solution, CaBr _TwoAqueous solution and KBr aqueous solution
Each was added simultaneously at an addition rate of 2 ml / min.
Generated. Keep warming and stirring for 2 hours after the addition is complete
The precipitate was aged.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
After vacuum drying at 0 ° C. for 4 hours, about 220 g of europium-activated barium fluorobromide crystals were obtained. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Comparative Example 1 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
r ₂ aqueous solution (2.5 mol / l) and 1200 ml,
7.5 ml of EuBr ₃ aqueous solution (0.2 mol / l)
, 2.98 g of KBr, and 1800 ml of water, the reaction mother liquor (BaBr ₂ concentration: 1.0 mol / l) was added to 4
Placed in a liter volume reactor. The reaction mother liquor in this reactor was kept at 60 ° C., and a screw-type stirring blade having a diameter of 45 mm provided with a mixing chamber having a volume of about 100 ml was used to rotate it at 500 rpm. The reaction mother liquor was stirred to generate.

NH ₄ F aqueous solution (10 mol / l) 1
An NH ₄ F diluted aqueous solution in which 50 ml and 150 ml of water were mixed, and 100 ml of a CaBr ₂ aqueous solution (0.15 mol / l) were separately prepared. Using a separate precision cylinder pump, 6 ml / NH ₄ F diluted aqueous solution was added to the mixing chamber in the reaction mother liquor kept warm under the above stirring.
Min, and a CaBr ₂ aqueous solution was simultaneously added at a rate of 2 ml / min to form a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Comparative Example 2 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
r ₂ aqueous solution (2.5 mol / l) and 1200 ml,
7.5 ml of EuBr ₃ aqueous solution (0.2 mol / l)
And 3.54 g of CaBr ₂ .2H ₂ O and 1800 m of water
l of the reaction mother liquor (BaBr ₂ concentration of 1.0 mol /
Liters) into a 4 liter volume reactor. The reaction mother liquor in this reactor was kept at 60 ° C., and a screw-type stirring blade having a diameter of 45 mm provided with a mixing chamber having a volume of about 100 ml was used to rotate it at 500 rpm. The reaction mother liquor was stirred to generate.

NH ₄ F aqueous solution (10 mol / l) 1
NH ₄ F diluted aqueous solution obtained by mixing 50 ml and water 150 ml, and KBr aqueous solution (0.25 mol / l)
100 ml were prepared separately. Using a separate precision cylinder pump, the NH ₄ F diluted aqueous solution was added at a rate of 6 ml / min and the KBr aqueous solution was added at a rate of 1 ml / min to the mixing chamber in the reaction mother liquor, which was kept warm under the above stirring. At the same time to form a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

Comparative Example 3 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
r ₂ aqueous solution (2.5 mol / l) and 1200 ml,
7.5 ml of EuBr ₃ aqueous solution (0.2 mol / l)
3.54 g of CaBr ₂ .2H ₂ O and 2.9 KBr
8 g and 1792.5 ml of water (Ba)
(Br ₂ concentration 1.0 mol / l) was placed in a 4 liter reactor. The reaction mother liquor in this reactor is kept at 60 ° C.
Using a 45-mm-diameter screw-type stirring blade provided with a mixing chamber having a volume of about 100 ml around the periphery thereof and rotating it at 500 rpm, the reaction mother liquor was stirred so as to generate an upward flow from the mixing chamber. .

NH ₄ F aqueous solution (10 mol / l) 1
An NH ₄ F diluted aqueous solution prepared by mixing 50 ml of water and 150 ml of water was prepared, and 6 ml of the diluted aqueous solution was added to the mixing chamber in the reaction mother liquor kept warm under the above stirring, using a precision cylinder pump.
/ Min at a rate of addition to produce a precipitate. After completion of the addition, the mixture was kept warm and stirred for 2 hours to ripen the precipitate.

Next, the precipitate was separated by filtration and washed with 2 liters of methanol. Then, the washed precipitate is taken out, and 12
Vacuum drying was performed at 0 ° C. for 4 hours to obtain about 330 g of europium-activated barium fluorobromide crystals. The obtained europium-activated barium fluorobromide crystal was fired in the same manner as in Example 1 to obtain europium-activated barium fluorobromide stimulable phosphor particles (Ba _0.99 Ca _0.01 FBr: 0.0003 K ·).
0.001 Eu ²⁺ ).

[Measurement of Shape of Phosphor Particles] With respect to the shape of each phosphor particle obtained in Examples 1 to 6 and Comparative Examples 1 to 3, a light diffraction type particle size distribution measuring apparatus (Horiba Seisakusho Co., Ltd.) The following measurements were carried out using a scanning electron microscope (JSM-5400LV, manufactured by JEOL Ltd.) and LA-500 (manufactured by a company). The results are summarized in Table 1 below.

Median diameter of particle size: The value measured by a light diffraction type particle size distribution measuring device was used as it is. Particle size distribution: Calculated from a distribution table measured by a light diffraction type particle size distribution measuring device. Particle shape: It was determined by observing a photograph obtained with a scanning electron microscope. Particle aspect ratio: Calculated by measuring and averaging the aspect ratio of 200 particles in a photograph obtained by a scanning electron microscope.

[Evaluation of Light Emission Characteristics of Phosphor] Example 1 above
-6 and each of the phosphors obtained in Comparative Examples 1 to 3,
The following light emission characteristics were evaluated. The results are summarized in Table 1 below.

Sensitivity: After irradiating the phosphor with X-rays of 80 kV and 100 mR, 12.4 He-Ne laser light is applied.
Irradiation was performed at J / m ² , the amount of stimulated emission from the phosphor was determined, and a sensitivity level value was calculated. Erased value: After irradiating the phosphor with X-rays of 80 kV and 100 mR, irradiating He-Ne laser beam at 12.4 J / m ² , the amount of stimulated emission from the phosphor was determined, and the initial amount of light emission (Initial value), and then irradiating this phosphor with a white phosphor under the conditions of 400,000 lx · s,
Laser light was applied at 12.4 J / m ² , and the amount of stimulated emission from the phosphor was determined to obtain an erasing level value. The value obtained by normalizing the erase level value with the initial value was used as the erase value.

[0082]

[Table 1]

As shown in Table 1 above, each additive was NH ₄
Examples 1 to 4 in which a phosphor was manufactured by adding simultaneously with an F aqueous solution
In the case of No. 6, it can be seen that, in comparison with Comparative Examples 1 to 3 in which each additive was previously added to the reaction mother liquor, the sensitivity and the erasing characteristics were very excellent.

[0084]

According to the present invention, the particle shape, particle aspect ratio, particle size (median diameter) of the rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor contained in the radiation image conversion panel, By controlling the particle size distribution, the image quality (especially sharpness and structural noise) of the radiation image conversion panel can be improved. Further, according to the present invention, in the synthesis of the rare earth activated alkaline earth metal fluoride halide stimulable phosphor precursor in the mother liquor, by adding each additive simultaneously with the aqueous solution of inorganic fluoride, The sensitivity and erasing characteristics of the obtained phosphor are greatly improved.

[Brief description of the drawings]

FIG. 1 shows the arrangement of a conventional plate-like rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor in a stimulable phosphor layer of a radiation image conversion panel, and the arrangement in the stimulable phosphor layer. It is a figure which shows the direction of light conduction typically.

FIG. 2 is a diagram schematically showing an arrangement of rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphors in a phosphor layer of a radiation image conversion panel and a direction of photoconductivity in the phosphor layer. It is.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G083 AA03 AA09 BB01 CC02 DD11 DD12 DD14 EE01 EE02 EE03 4G076 AA05 AA06 AA07 AA08 AA09 AA11 AA12 AA18 BA13 BA38 BC02 BD02 CA02 DA11 4H001 CF02 XA09 XA17 XAYA XA17 XA18 XA17 XA18 XA17 YA55 YA58 YA59 YA60 YA62 YA63 YA64 YA65 YA69 YA70

Claims (8)

[Claims] 1. A basic composition formula (I): Ba _{1 -x} M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one kind selected from the group consisting of Sr and Ca. represents an alkaline earth metal, M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and the standard deviation of the particle size distribution is σ / Dm
Is in the range of 50% or less, and the particle aspect ratio is in the range of 1.0 to 2.0, the method for producing a rare earth activated alkaline earth metal fluoride halide stimulable phosphor, BaX ₂ ; when x in the above-mentioned basic composition formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^II ; and when y in the above-mentioned basic composition formula (I) is not 0, further M ^I halide, nitrate, nitrite or acetate; (. However, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salt, excluding) an aqueous solution containing and dissolving them A mother liquor preparation step of preparing a reaction mother liquor having a BaX ₂ concentration of 2.5 mol / l or less when X is Cl or Br, and 5.0 mol / l or less when X is I; The reaction mother liquor is While maintaining the temperature, and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, a halide of M ^I, nitrate, an aqueous solution of nitrite or acetate and / or M ^II halides , Nitrate, nitrite or acetate aqueous solution,
Simultaneously forming a precipitate of the phosphor precursor crystal, a separating step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, and a precipitation of the separated phosphor precursor crystal. A sintering step of sintering the material while avoiding sintering. A method for producing a rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor. 2. Basic composition formula (I): Ba _{1 -x} M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one kind selected from the group consisting of Sr and Ca. represents an alkaline earth metal, M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and the standard deviation of the particle size distribution is σ / Dm
Is in the range of 50% or less, and the particle aspect ratio is in the range of 1.0 to 2.0, the method for producing a rare earth activated alkaline earth metal fluoride halide stimulable phosphor, BaX ₂ ; water-soluble compound of Ln; the above-mentioned basic composition formula (I)
If x in formula (I) is not 0, then halide, nitrate, nitrite or acetate of M ^II ;
Halide of further M ^I in the case of y is not 0, nitrate, nitrite or acetate; (however, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salts are excluded.) The A reaction in which the BaX ₂ concentration is 2.5 mol / L or less when X is Cl or Br and 5.0 mol / L or less when X is I and mother liquor preparation step of preparing a mother liquor, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C., and an aqueous solution of an inorganic fluoride salt thereto, and an aqueous solution containing a water-soluble compound of Ln, halide M ^I And an aqueous solution of nitrate, nitrite or acetate and / or an aqueous solution of halide, nitrate, nitrite or acetate of M ^II (except when both x and y in the above basic composition formula (I) are both 0) , A precipitate forming step of adding a precipitate of the phosphor precursor crystal at the same time, a separating step of separating the precipitate of the phosphor precursor crystal from an aqueous solution, and a precipitate of the separated phosphor precursor crystal And a sintering step of sintering while avoiding sintering. A method for producing a rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor. 3. Basic composition formula (I): Ba _{1 -x} M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one kind selected from the group consisting of Sr and Ca. represents an alkaline earth metal, M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and the standard deviation of the particle size distribution is σ / Dm
Is in the range of 50% or less, and the particle aspect ratio is in the range of 1.0 to 2.0, the method for producing a rare earth activated alkaline earth metal fluoride halide stimulable phosphor, NH ₄ X; when x in the above formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^II ; and when y in the above basic formula (I) is not 0, further M ^I halide, nitrate, nitrite or acetate; (. However, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salt, excluding) an aqueous solution containing and dissolving them and mother liquor preparation process of NH ₄ X concentration after to prepare a reaction mother liquor is less than 4.5 mol / liter, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C., and an aqueous solution of BaX ₂ thereto, An aqueous solution of an inorganic fluoride salt;
an aqueous solution containing n-soluble compounds of a halide of M ^I, nitrates, halides of nitrite or an aqueous solution of acetate and / or M ^II, nitrate, and an aqueous solution of a nitrite or acetate simultaneously and, A precipitate forming step of forming a precipitate of the phosphor precursor crystal by adding the ratio of the inorganic fluoride to BaX ₂ so as to keep the ratio constant, and separating the precipitate of the phosphor precursor crystal from the aqueous solution And a firing step of firing the separated precipitates of the phosphor precursor crystals while avoiding sintering. A method for producing a phosphor. 4. A basic composition formula (I): Ba _{1 -x} M ^II _x FX: y M ^I , zLn (I) [where M ^II is at least one kind selected from the group consisting of Sr and Ca. represents an alkaline earth metal, M ^I is Li,
X represents at least one alkali metal selected from the group consisting of Na, K, Rb and Cs, and X represents Cl, Br and I
Ln represents Ce, Pr, Sm, Eu, Gd, Tb, Tm
And at least one rare earth element selected from the group consisting of Yb and Xb, x, y and z are 0 ≦ x ≦ 0.5, 0 ≦
Numerical values in each range of y ≦ 0.05 and 0 <z ≦ 0.2 are shown. And the median diameter (Dm) of the particle size is 1 to 10 μm, and the standard deviation of the particle size distribution is σ / Dm
Is in the range of 50% or less, and the particle aspect ratio is in the range of 1.0 to 2.0, the method for producing a rare earth activated alkaline earth metal fluoride halide stimulable phosphor, NH ₄ X; a water-soluble compound of Ln; the above basic composition formula (I)
When x in formula (I) is not 0, further halides, nitrates, nitrites or acetates of M ^II ;
An aqueous solution containing (however, among these components, ingredients added without lack at the same time as the aqueous solution of an inorganic fluoride salts are excluded.); Halide of further M ^I when but not 0, nitrate, nitrite or acetate And a mother liquor preparation step of preparing a reaction mother liquor having an NH ₄ X concentration of 4.5 mol / liter or less after dissolving them, while maintaining the reaction mother liquor at a temperature of 20 to 100 ° C. An aqueous solution of BaX _2, an aqueous solution of an inorganic fluoride salt,
an aqueous solution containing n-soluble compounds of a halide of M ^I, nitrates, halides of nitrite or an aqueous solution of acetate and / or M ^II, nitrate, an aqueous solution of nitrite or acetate (the basic compositional formula ( I) x and y
At the same time, and the addition of inorganic fluoride to maintain the ratio of fluorine to BaX ₂ constant to form a precipitate of phosphor precursor crystals. A separating step of separating a precipitate of the phosphor precursor crystal from an aqueous solution, and a firing step of firing the separated precipitate of the phosphor precursor crystal while avoiding sintering. For producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor. 5. A phosphor precursor formed during the addition of an aqueous solution of an inorganic fluoride salt in a precipitate forming step, wherein the amount of the precipitate of the phosphor precursor crystal finally obtained is N. The amount of the precipitate of the body crystal is 0.001 N / min to 10
3. The rare earth activated alkaline earth metal fluorohalide-based luminous composition according to claim 1, wherein the addition rate is adjusted so as to be in the range of N / min, and the aqueous solution of the inorganic fluoride salt is added. Method for producing depleted phosphor. 6. An inorganic fluoride salt in a precipitation forming step.
Aqueous solution and BaX _TwoWhen adding an aqueous solution of
When the amount of the obtained phosphor precursor crystal precipitate is N
In addition, the amount of phosphor precursor crystal precipitates
Add so as to be in the range of 0.001 N / min to 10 N / min
By adjusting the rate, an aqueous solution of inorganic fluoride salt and BaX_Two
5. An aqueous solution of the above (3) or (4).
Rare earth activated alkaline earth metal fluorinated halides as described in
Method for producing stimulable phosphor. 7. The rare earth-activated alkaline earth metal fluoride halide system according to claim 1, wherein the inorganic fluoride salt is ammonium fluoride or an alkali metal fluoride. A method for producing a stimulable phosphor. 8. A precipitate generating step, to be added an aqueous solution of an inorganic fluoride salt at the same time, the addition of an aqueous solution other than the aqueous solution and the aqueous solution of BaX ₂ of inorganic fluoride salts, in addition time, addition rate are continuously 8. The method for producing a rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor according to claim 1, wherein the phosphor is changed intermittently.