JP2000192030A - Preparation of rare earth-activated, alkaline earth metal fluoride halide-based stimulable phosphor and reactor used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a phosphor with good sensitivity and particulate properties by adding an inorganic fluoride salt and a halide or the like of Ba at a specified temperature to a mother liquor prepared from a water solution of a halide or the like of NH4, an alkali metal, or an alkaline earth metal and a water solution of a rare earth element to precipitate a precursor and separating and baking the precursor. SOLUTION: A water solution of an inorganic fluoride salt and a BaX2 is added, at 20-100 deg.C under stirring, to a mother liquor which is prepared from a water solution of NH4X or a halide, a nitrate, or the like of M" or M' and a water solution of a water-soluble Ln compound, 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 1.0-10 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 Li, Na, K, or the like; X is Cl, Br, or I; Ln is Ce, Sm, Pr, Eu, or the like; 0<=x<=0.5; 0<=y<=0.5; and 0<z<=0.2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor, and more particularly to a tetradecahedral rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor. It relates to a method for producing a body.

[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, applying 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. 6), and therefore, there is a problem that the sharpness of a radiation-reproduced image obtained tends to decrease.

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.

Japanese Patent Application Laid-Open No. Hei 7-233369 discloses a tetrahedral rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor having a controlled particle shape and particle aspect ratio (hereinafter simply referred to as "phosphor"). ) Is shown. Radiation image conversion panel having a stimulable phosphor layer on which a tetradecahedral rare earth activated alkaline earth metal fluorinated halide stimulable phosphor (hereinafter sometimes simply referred to as “tetrahedral phosphor”) is disposed. In FIG. 7, as shown in FIG. 7, in the stimulable phosphor layer, the tetradecahedral phosphor exhibits an arrangement with less directivity, so that the undesired spread of the excitation light and the stimulable emission light in the lateral direction is reduced. Thus, the sharpness of the obtained radiation reproduction image is improved.

In the production method disclosed in the above publication, an ammonium halide is used as a reaction mother liquor, and an aqueous solution of barium halide and an aqueous solution of an inorganic fluoride salt are simultaneously added to the mother liquor to cause the reaction to proceed. Although a fluorescent phosphor is synthesized, it tends to take a particle shape having a high particle aspect ratio. On the other hand, by adding barium halide to the reaction mother liquor in advance, the aspect ratio can be made close to 1 to some extent, but at present it is not sufficient in terms of controllability of particle shape, particle size, and particle size distribution. .

[0011]

SUMMARY OF THE INVENTION The present invention relates to a rare-earth activated alkaline earth metal fluoride halide-based phosphor having high controllability of the particle shape, particle size and particle size distribution of the resulting stimulable phosphor particles. It is an object of the present invention to provide a novel method for producing a depleted phosphor. In particular, when used in a radiation image conversion panel, a high-quality image showing extremely high sharpness is obtained, and at the same time, a rare-earth activated alkaline earth metal fluorinated halide-based stimulable phosphor having excellent sensitivity and granularity is obtained. And a reaction apparatus used for the same.

[0012]

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 fluoride halide stimulable phosphor having a ratio in the range of 1.0 to 2.0, wherein NH ₄ X; Ln
A water-soluble compound of the formula (I): when x in the formula (I) is not 0, a halide, nitrate, nitrite or acetate of M ^II ; and when y in the formula (I) is not 0: halides Furthermore M ^I, nitrate, nitrite or acetate; an aqueous solution containing, and, NH ₄ X concentration 2. or less 0 mole / liter to 4.5 moles / liter after they have dissolved A mother liquor preparation step in which a reaction mother liquor is prepared, and the reaction mother liquor is maintained at a temperature of 20 to 100 ° C. and stirred; and an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are stirred at a high speed while adding the phosphor precursor. A crystal nucleus forming step of forming a crystal nucleus of a body crystal and introducing the reacted suspension into the stirred reaction mother liquor while maintaining the temperature at 20 to 100 ° C .; 20-10
While maintaining the temperature at 0 ° C., an aqueous solution of BaX _{2 and} an aqueous solution of an inorganic fluoride salt were simultaneously added thereto, and the molar ratio of fluorine of the inorganic fluoride salt to BaX ₂ was kept constant. A precipitate forming step of forming a precipitate of the phosphor precursor crystal by heating, a separating step of separating the precipitate of the phosphor precursor crystal from the aqueous solution, and firing the separated precipitate of the phosphor precursor crystal. And a baking step of baking while avoiding sintering. A method for producing a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor, comprising:

<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 fluorohalide-based stimulable phosphor having a ratio in the range of 1.0 to 2.0, wherein BaX ₂ ; Ln
A water-soluble compound of the formula (I): when x in the formula (I) is not 0, a halide, nitrate, nitrite or acetate of M ^II ; and when y in the formula (I) is not 0: halides Furthermore M ^I, nitrate, nitrite or acetate; an aqueous solution containing, and they are BaX ₂ concentration after dissolution, if X is Cl or Br 2.5 mole / liter or less, 5.0 when X is I
A mother liquor preparation step of preparing a reaction mother liquor of not more than mol / liter, maintaining the reaction mother liquor at a temperature of 20 to 100 ° C. and stirring, and an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ ,
A crystal nucleus forming step of forming a crystal nucleus of the phosphor precursor crystal by high-speed stirring while adding, and introducing the reacted suspension into the stirred reaction mother liquor while maintaining the temperature at 20 to 100 ° C. Depositing a phosphor precursor crystal by adding an aqueous solution of an inorganic fluoride salt thereto while maintaining the reaction mother liquor containing the suspension at a temperature of 20 to 100 ° C., 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.

<3> 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.
a method for producing a rare earth activated alkaline earth metal fluorohalide stimulable phosphor according to <1>, wherein the adding an aqueous solution of aX _2. <4> 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 precursor crystal generated during the addition is added. The rare earth activation according to <1>, wherein the addition rate is adjusted so that the amount of the precipitates in the range of 0.001 N / min to 10 N / min is added, and the aqueous solution of the inorganic fluoride salt is added. This is a method for producing an alkaline earth metal fluorohalide-based stimulable phosphor. <5> When the aqueous solution of the inorganic fluoride salt and the aqueous solution of BaX ₂ are added in the crystal nucleus formation step, the amount of the precipitate of the phosphor precursor crystal finally obtained in the precipitate formation step is changed to N.
In this case, the aqueous solution of the inorganic fluoride salt and the BaX ₂ are formed such that the amount of crystal nuclei of the phosphor precursor crystals in the crystal nucleus forming step is in the range of more than 0N and 0.8N or less.
<1> to <4, characterized by adding an aqueous solution of
> The method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor according to any one of <1> to <3>. <6> The rare earth activated alkaline earth metal fluoride halide system according to any one of <1> to <5>, wherein the inorganic fluoride salt is ammonium fluoride or an alkali metal fluoride. This is a method for producing a stimulable phosphor. <7> The method according to any one of <1> to <6>, wherein, in the crystal nucleus forming step, the aqueous solution of the inorganic fluoride salt and the aqueous solution of BaX ₂ are stirred at a high speed using an instantaneous reaction device. The method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor of the present invention. <8> Two or more liquid applicators for accommodating and sending the liquid to the outside, and the liquid sent from the two or more liquid applicators are accommodated therein, stirred at a high speed, and then sent to the outside. Having an instant reaction device, and a stirring tank for containing the liquid sent from the two or more liquid adders and the solution sent from the instant reaction device, and stirring it together with the reaction mother liquor previously contained therein A reactor characterized by the following.

[0015]

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 fluorohalide-based 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.
２．０2.0 (more preferably 1.0 to 1.5), and the median diameter (Dm) of the particle size is 1 to 10 μm.
(More preferably, 3 to 7 μm), and σ / Dm is 50 when the standard deviation of the particle size distribution is σ.
% Or less (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. If it satisfies, it is not necessarily limited to the tetrahedral type,
The effects of the present invention can be achieved.

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.

Production Method The rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor of the present invention is produced by the following two production methods (A) and (B).

(A) NH_FourX; a water-soluble compound of Ln;
When x in the above basic composition formula (I) is not 0, M
^IIHalides, nitrates, nitrites or acetates of:
When y in the above basic composition formula (I) is not 0, M
^IHalides, nitrates, nitrites or acetates of:
And an aqueous solution containing
_FourX concentration is 2.0 mol / L or more and 4.5 mol / L
Prepare a reaction mother liquor that is less than
A mother liquor preparation step of maintaining and stirring at a temperature of 100 ° C .;
Aqueous solution of fluoride salt and BaX_TwoWith the aqueous solution of
Stirring at high speed to form crystal nuclei of phosphor precursor crystals.
The corresponding suspension is maintained at the aforementioned temperature of 20 to 100 ° C. and stirred.
A crystal nucleus forming step to be introduced into the reaction mother liquor,
Maintain the reaction mother liquor containing the suspension at a temperature of 20-100 ° C.
Meanwhile, this is BaX_TwoAqueous solution and inorganic fluoride salt water
Simultaneously with the solution, fluorine of inorganic fluoride salt and BaX_Two
To keep the molar ratio constant with the phosphor
A precipitate forming step of forming a precipitate of precursor crystals;
Separation step for separating precipitates of photoprecursor crystals from aqueous solution
And sintering the separated precipitate of the phosphor precursor crystal.
And baking while avoiding.
Rare earth activated alkaline earth metal fluoride halide luminosity
Method for producing depleted 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;
When y in the above basic composition formula (I) is not 0, M
^I halide, nitrate, nitrite or acetate;
And an aqueous solution containing Ba
When X ₂ concentration is 2.5 mol /% when X is Cl or Br,
Liter or less, and when X is I, a reaction mother liquor of 5.0 mol / l or less is prepared.
A mother liquor preparation step of stirring and maintaining at a temperature of ℃, and an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are stirred at a high speed while being added to form crystal nuclei of phosphor precursor crystals and react with the suspension. A crystal nucleus forming step of introducing the liquid into the stirred reaction mother liquor at a temperature of 20 to 100 ° C., and maintaining the reaction mother liquor containing the suspension at a temperature of 20 to 100 ° C. A precipitate forming step of adding an aqueous solution of an inorganic fluoride salt to generate a precipitate of a phosphor precursor crystal; a separating step of separating the precipitate of the phosphor precursor crystal from an 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 precursor crystal while avoiding sintering.

In the present invention, the "aqueous solution"
"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.). The manufacturing methods (A) and (B) will be described separately for each step.

[Production Method (A)] i) Mother Liquid Preparation Step First, a raw material compound other than a fluorine compound is dissolved using an aqueous medium to prepare a reaction mother liquid. That is, NH ₄ X
A water-soluble compound of Ln, and optionally halides of M ^II, nitrate, nitrite or acetate salt, if necessary, a halide of M ^I, nitrate, nitrite or acetate, the aqueous medium The components are thoroughly mixed and dissolved to prepare an aqueous solution (reaction mother liquor) in which these components are dissolved. At this time, the NH ₄ X concentration is from 2.0 mol / L to 4.5 mol / L, preferably 3.0 mol / L or less.
The molar ratio between NH ₄ X and the aqueous solvent is adjusted so as to be not less than mol / L and not more than 4.5 mol / L. Ln
Examples of the water-soluble compounds include halides (chlorides, bromides, etc.) of the above-mentioned rare earth elements, nitrates, acetates, and the like. 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. The reaction mother liquor obtained above is
Maintained at 20-100 ° C, preferably 40-80 ° C,
And it is stirred.

Ii) Crystal nucleus forming step An aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ (hereinafter sometimes referred to as “reaction solution”) and, if necessary, an aqueous solution of ammonium halide as a carrier solution. At the same time using a known metering pump, for example, a precision cylinder pump, a precision gear pump, a tube pump, a diaphragm pump or the like. Among these, a precision cylinder pump is preferable. In order to stir the added reaction solution at a high speed, an instant reaction device is preferably used. Crystal nuclei of phosphor precursor crystals are generated by high-speed stirring while adding the reaction solution. Examples of inorganic fluoride salts include ammonium fluoride, alkali metal fluoride, alkaline earth metal fluoride, transition metal fluoride, hydrofluoric acid and the like. From the viewpoint of pH change, ammonium fluoride and fluorides of alkali metals are preferred.

When an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are added and the amount of the precipitate of the phosphor precursor crystal finally obtained in the precipitate formation step is defined as N, this crystal nucleation step And an aqueous solution of an inorganic fluoride salt and BaX ₂ so that the amount of crystal nuclei of the phosphor precursor crystal in step (b) is more than 0N and not more than 0.8N (more preferably in the range of 0.05 to 0.3N). Is preferably added. If the amount of the crystal nuclei is larger than 0.8 N, crystal growth may not be sufficiently performed, and irregular fine particles may be formed.

The instant reaction apparatus preferably used in the present invention refers to an apparatus for rapidly and uniformly mixing the reaction solution.
Preferably, the instant reaction device is a device capable of mixing uniformly faster than the reaction speed of the substance. For example, it is preferable that a uniform nucleus of ultrafine particles be generated by causing instantaneous mixing and reaction by a pair of stirring means rotating at high speed above and below a cell having a limited volume. The suspension containing the generated crystal nuclei is sequentially extruded from the reaction cell by the addition of the reaction liquid or the carrier liquid, and is added to the reaction mother liquor maintained at 20 to 100 ° C. and stirred. In the present invention, in addition to particle shape, particle aspect ratio, particle size,
The purpose is to simultaneously control the particle size distribution, and in these crystal nucleus forming steps of the phosphor precursor crystals, to stir at high speed while adding the reaction solution to determine the number of generated crystal nuclei. Can be achieved.

Iii) Precipitate formation step While maintaining the reaction mother liquor containing the suspension at a temperature of 20 to 100 ° C., the aqueous solution of the inorganic fluoride salt and Ba are added thereto.
And an aqueous solution of X ₂ simultaneously, fluorine inorganic fluoride salts and BaX
_In order to maintain a constant molar ratio with ₂ , a known metering pump, for example, a precision cylinder pump, a precision gear pump, a tube pump, a diaphragm pump or the like is used. Of these, the addition is preferably performed using a precision cylinder pump to grow the crystal nuclei of the phosphor precursor crystals and obtain a precipitate of the phosphor precursor crystals.

When the amount of the precipitate of the phosphor precursor crystal finally obtained is N when the aqueous solution of the inorganic fluoride salt and the aqueous solution of BaX ₂ are added, 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, it may not be possible to take sufficient time for uniform mixing.On the other hand, if the addition speed is lower than the above, the residence time in the reaction cell may be too long to cause crystal growth in the cell. There is. In order to precisely adjust the rate of addition, it is preferable to add with a precision cylinder pump. Further, the addition is usually performed at a constant addition rate, but the addition rate is n with respect to the addition time.
It may change continuously or intermittently in the following function (n = 1, 2, 3), exponential function, or differential function. This addition is preferably carried out in the region where the stirring is particularly vigorous.

Iv) Separation Step The precipitate of the phosphor precursor crystal obtained as described above is separated from the aqueous solution by a 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.

V) 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 fine particles 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 method (B)] i) Step of preparing mother liquor First, a starting compound other than a fluorine compound is dissolved using an aqueous medium to prepare a reaction mother liquor. That is, BaX ₂
A water-soluble compound of Ln, and optionally halides of M ^II, nitrate, nitrite or acetate salt, if necessary, a halide of M ^I, nitrate, nitrite or acetate, the aqueous medium The components are thoroughly mixed and dissolved to prepare an aqueous solution (reaction mother liquor) in which these components are dissolved. At this time, when X is Cl or Br, Ba
The amount ratio between BaX ₂ and the aqueous solvent is adjusted so that the X ₂ concentration is 2.5 mol / l or less, and when X is I, the BaX ₂ concentration is 5.0 mol / l or less. Ln
Examples of the water-soluble compounds include halides (chlorides, bromides, etc.), nitrates, acetates, and the like of the rare earth elements. The reaction mother liquor contains a small amount of acid, ammonia,
A water-soluble polymer, a water-insoluble metal oxide fine particle powder, or the like may be added. The reaction mother liquor obtained above was 20
-100 ° C, preferably 40-80 ° C, and stirred.

Ii) Crystal nucleus forming step An aqueous solution of an inorganic fluoride salt, an aqueous solution of BaX ₂ and, if necessary, an aqueous solution of ammonium halide as a carrier liquid are simultaneously supplied with a known quantitative pump, for example, a precision cylinder pump, a precision cylinder pump, Add using a gear pump, tube pump, diaphragm pump, etc. Among these,
Precision cylinder pumps are preferred. In order to stir the added reaction solution at a high speed, an instant reaction device is preferably used. Crystal nuclei of phosphor precursor crystals are generated by high-speed stirring while adding the reaction solution. Examples of inorganic fluoride salts include ammonium fluoride, alkali metal fluoride, alkaline earth metal fluoride, transition metal fluoride, hydrofluoric acid and the like. From the viewpoint of pH change, ammonium fluoride and fluorides of alkali metals are preferred.

When an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are added, and the amount of the precipitate of the phosphor precursor crystal finally obtained in the precipitate formation step is set to N, this crystal nucleus forming step And an aqueous solution of an inorganic fluoride salt and BaX ₂ so that the amount of crystal nuclei of the phosphor precursor crystal in step (b) is more than 0N and not more than 0.8N (more preferably in the range of 0.05 to 0.3N). Is preferably added. If the amount of the crystal nuclei is larger than 0.8 N, the crystal growth may not be sufficiently performed and the particles may be irregularly shaped.

The instant reaction apparatus preferably used here is the same as that used in the production method (A). The suspension containing the generated crystal nuclei is sequentially extruded from the reaction cell by the addition of the reaction solution or the carrier solution, and
It is added to the stirred reaction mother liquor maintained at 0-100 ° C. In the present invention, it is an object to simultaneously control the particle aspect ratio, the particle size, and the particle size distribution in addition to the particle shape, and in the crystal nucleus forming step of the phosphor precursor crystal, the reaction liquid is added. This can be achieved by high-speed stirring while determining the number of crystal nuclei to be formed.

Iii) Precipitate formation step While maintaining the reaction mother liquor containing the suspension at a temperature of 20 to 100 ° C., the aqueous solution of the inorganic fluoride salt is added thereto with a known quantitative pump, for example, a precision cylinder pump. , A precision gear pump, a tube pump, a diaphragm pump or the like. Of these, the addition is preferably performed using a precision cylinder pump to grow the crystal nuclei of the phosphor precursor crystals and obtain a precipitate of the phosphor precursor crystals.

When the amount of the precipitate of the phosphor precursor crystals finally obtained upon adding the aqueous solution of the inorganic fluoride salt is set to N, the amount of the precipitate of the phosphor precursor crystals formed during the addition 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, it may not be possible to take sufficient time for uniform mixing.On the other hand, if the addition speed is lower than the above, the residence time in the reaction cell may be too long to cause crystal growth in the cell. There is. In order to precisely adjust the rate of addition, it is preferable to add with a precision cylinder 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.

Iv) Separation Step and Firing Step The precipitate of the phosphor precursor crystal obtained as described above is separated from an aqueous solution by a separation step, and the separated precipitate of the phosphor precursor crystal is sintered. 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 sintering separation step are the same as in the production method (A).

Reactor The reactor of the present invention is preferably used in the above-mentioned method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor. The reactor of the present invention contains two or more liquid adders for containing and sending the liquid to the outside, and contains therein the liquid sent from the two or more liquid adders, and after stirring at high speed, An instantaneous reaction device for sending to the outside, a stirring tank for containing the solution sent from the two or more liquid adders and the solution sent from the instantaneous reaction device, and stirring it together with the reaction mother liquor contained in advance therein; And a reaction device comprising:

The reaction apparatus of the present invention further comprises a switching valve for sending the liquid contained in one of the two or more liquid adders to the instantaneous reaction apparatus or the stirring tank, and another one. A switching valve for sending the liquid stored in the liquid addition device to the instant reaction device or the stirring tank. In the present invention, the number of the liquid adders and the type of liquid contained in the liquid adder are not particularly limited, and can be appropriately selected according to the purpose. Further, in the present invention, an embodiment provided with the switching valve is preferable, but an embodiment not provided with the switching valve, that is, a liquid adding device for sending the liquid only to the instantaneous reaction device and sending the liquid only to the stirring tank are provided. The liquid addition device may be separately provided.

Hereinafter, the reaction apparatus of the present invention will be described with reference to the drawings, but the present invention is not limited thereto. FIG. 1 is a schematic diagram showing one example of the reaction apparatus of the present invention. Three precision cylinder pumps 101, 102, 10
The first reaction liquid 104, the second reaction liquid 105, and the carrier liquid 106 are stored in each of the precision cylinder pumps. The precision cylinder pump is designed so that the amount and rate of addition of these reaction solutions can be precisely adjusted. Below the precision cylinder pump, a precision cylinder pump 1
There is provided an instant reaction device 107 which accommodates a part of the liquid sent out from 02, 103, 104 inside, stirs it at high speed, and sends it out. In the instant reaction device 107,
Stirring means 108 and 109 are provided. The instant reaction device will be described later in detail.

Below the instant reaction device 107, another part of the liquid sent from the precision cylinder pumps 101 and 102 and the liquid sent from the instant reaction device 107 are stored, and a reaction mother liquor previously stored inside is stored. A reactor 113 is provided as a stirring tank for stirring together. Reactor 1
The volume of 13 represents the total amount of product obtained by the reaction as N (mo
Assuming that 1), 0.01N to 100N (liter) is preferable, and 0.1N to 10N (liter) is more preferable. The shape of the reactor 113 is not particularly limited as long as the effect of the present invention is not impaired. Reactor 1
The liquid in 13 is stirred by the rotation of the stirring blade 116 accompanying the driving of the stirring motor 115. This rotation speed is
About 100-10000 rpm, 500-500
0 rpm is preferred. During the stirring, the liquid is heated by a temperature controller 112, preferably at 20 to 100 ° C, more preferably at 40 ° C.
Maintained at ８０80 ° C. In the reaction apparatus shown in FIG. 1, a switching valve 110 for sending the first reaction liquid 104 stored in the precision cylinder pump 101 to the instantaneous reaction apparatus 107 or the reactor 113, and a second reaction liquid stored in the precision cylinder pump 102 A switching valve 111 for delivering the liquid 105 to the instantaneous reaction device 107 or the reactor 113 is provided.

Next, an example of the instant reaction apparatus is shown in FIG.
This will be described in detail with reference to FIG. Instant reaction device 200
Is provided with a pair of stirring means 201 and 202 that rotate at high speed above and below the reaction cell 203. Stirring means 201, 2
The rotation speed of No. 02 is about 100 to 10000 rpm, preferably 1000 to 5000 rpm. Reaction cell 2
03, the total amount obtained by the reaction is N (m
ol), 0.01N to 100N (ml) is preferable, and 0.1N to 10N (ml) is more preferable. The shape of the reaction cell is not particularly limited, but a cylindrical shape is preferable. Inside the reaction cell 203, stirring means 201,
With the driving of 202, the stirrers 204 and 205 that can be rotated by magnetic force or directly connected to the motor rotation shaft rotate. Although the shape of the stirrers 204 and 205 is not particularly limited, for example, a shape as shown in FIG. FIG.
The upper stage is a stirrer in the shape of a flat plate with a cross-shaped bottom. The middle part of FIG. 3 is a stirrer having a thin cylindrical base and a cross-shaped convex provided on the surface thereof.
The lower part of FIG. 3 is a substantially cylindrical stirrer. Stirrer 20
It is preferable that the rotations 4 and 205 rotate in opposite directions.

In the instant reaction apparatus 200 shown in FIG. 2, the first reaction solution 104
The carrier liquid 106 from the direction and the second reaction liquid 105 from the direction of the arrow C respectively feed the precision cylinder pump 10.
1, 103 and 102 are added into the reaction cell 203, but other ports may be used and are not limited thereto. The added liquid is rapidly and uniformly mixed in the reaction cell 203 by the stirring means 201 and 202.
The mixed suspension is the first reaction liquid 1 to be added later.
04, the second reaction liquid 105 and the carrier liquid 106 sequentially extrude the reaction cell 203 in the direction of arrow D and introduce it into the mixing chamber 114 in the reactor 113.

Method for Manufacturing Radiation Image Conversion Panel Next, a method for manufacturing a radiation image conversion panel using the rare earth activated alkaline earth metal fluoride 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 (hereinafter sometimes simply referred to as “stimulable phosphor”) obtained by the production method of the present invention 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 comprises 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 on the support as described above, the coating 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

[0053]

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, NH _{4 was used.}
1560 ml of Br aqueous solution (4.5 mol / l) and E
5 ml of a uBr ₃ aqueous solution (0.2 mol / l) and water 4
35 ml of the reaction mother liquor (NH ₄ Br concentration: 3.5)
Mol / l) into a 4 liter 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 (2.5 mol / l)
80 ml and BaBr ₂ aqueous solution (2.5 mol / l)
80 ml of NH ₄ Br aqueous solution (4.5 mol / l) and 340 ml of NH ₄ Br aqueous solution at the same time using separate precision cylinder pumps.
those having a cylindrical cell having an inner volume of 2ml which stirrer the mm is reversely rotated to each other in 3000 rpm), NH ₄
The aqueous F solution and the aqueous BaBr ₂ solution were added at a rate of 20 ml / min, and the aqueous NH ₄ Br solution was added at a rate of 85 ml / min to react. The suspension after the reaction was extruded from the cell with the addition, and introduced into the mixing chamber in the reaction mother liquor kept warm under the stirring.

Subsequently, 320 ml of an NH ₄ F aqueous solution (2.5 mol / l) and a BaBr ₂ aqueous solution (2.5 mol / l) were used.
Liter) were separately prepared. Using a separate precision cylinder pump, NH ₄ F was added to the mixing chamber in the reaction mother liquor containing the suspension, which was kept warm under the above stirring.
And such that the molar ratio of BaBr ₂ is constant 8 ml /
At the same time 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
After vacuum drying at 0 ° C. for 4 hours, about 220 g of europium-activated barium fluorobromide crystals were obtained. 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 (BaFB).
r: 0.001 Eu ²⁺ ).

Example 2 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) and E
5 ml of an aqueous uBr ₃ solution (0.2 mol / l) and water 2
15 ml of the reaction mother liquor (NH ₄ Br concentration: 4.0)
Mol / l) into a 4 liter 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 (2.5 mol / l)
80 ml and BaBr ₂ aqueous solution (2.5 mol / l)
80 ml of NH ₄ Br aqueous solution (4.5 mol / l) and 340 ml of NH ₄ Br aqueous solution at the same time using separate precision cylinder pumps.
those having a cylindrical cell having an inner volume of 2ml which stirrer the mm is reversely rotated to each other in 3000 rpm), NH ₄
The F aqueous solution and the BaBr ₂ aqueous solution were added at a rate of 80 ml / min, and the NH ₄ Br aqueous solution was added at a rate of 340 ml / min to react. The suspension after the reaction was extruded from the cell with the addition, and introduced into the mixing chamber in the reaction mother liquor kept warm under the stirring.

Subsequently, 320 ml of an NH ₄ F aqueous solution (2.5 mol / l) and a BaBr ₂ aqueous solution (2.5 mol / l)
Liter) were separately prepared. Using a separate precision cylinder pump, NH ₄ F was added to the mixing chamber in the reaction mother liquor containing the suspension, which was kept warm under the above stirring.
And such that the molar ratio of BaBr ₂ is constant 8 ml /
At the same time 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
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 (BaFBr: 0.001Eu ²⁺ ).

Example 3 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
r2 aqueous solution ( _2.5 mol / l) 800 ml and Eu
5 ml of an aqueous Br ₃ solution (0.2 mol / l) and water 11
95 ml of the reaction mother liquor (BaBr ₂ concentration: 1.0)
Mol / l) into a 4 liter 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 (2.5 mol / L)
80 ml and BaBr ₂ aqueous solution (2.5 mol / l)
80 ml of NH ₄ Br aqueous solution (4.5 mol / l) and 340 ml of NH ₄ Br aqueous solution at the same time using separate precision cylinder pumps.
those having a cylindrical cell having an inner volume of 2ml which stirrer the mm is reversely rotated to each other in 3000 rpm), NH ₄
The F aqueous solution and the BaBr ₂ aqueous solution were added at a rate of 80 ml / min, and the NH ₄ Br aqueous solution was added at a rate of 340 ml / min to react. The suspension after the reaction was extruded from the cell with the addition, and introduced into the mixing chamber in the reaction mother liquor kept warm under the stirring.

Subsequently, 320 ml of an NH ₄ F aqueous solution (2.5 mol / l) was prepared, and a precision cylinder pump was placed in a mixing chamber in the reaction mother liquor containing the suspension, which was kept warm under the above stirring. Was used at an addition rate of 8 ml / min 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
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 (BaFBr: 0.001Eu ²⁺ ).

Example 4 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaB was used.
960 ml of r ₂ aqueous solution (2.5 mol / l) and Eu
5 ml of a Br ₃ aqueous solution (0.2 mol / l) and water 10
35 ml of reaction mother liquor (BaBr ₂ concentration: 1.2)
Mol / l) into a 4 liter 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 (2.5 mol / l)
80 ml and BaBr ₂ aqueous solution (2.5 mol / l)
80 ml of NH ₄ Br aqueous solution (4.5 mol / l) and 340 ml of NH ₄ Br aqueous solution at the same time using separate precision cylinder pumps.
those having a cylindrical cell having an inner volume of 2ml which stirrer the mm is reversely rotated to each other in 3000 rpm), NH ₄
The F aqueous solution and the BaBr ₂ aqueous solution were added at a rate of 80 ml / min, and the NH ₄ Br aqueous solution was added at a rate of 340 ml / min to react. The suspension after the reaction was extruded from the cell with the addition, and introduced into the mixing chamber in the reaction mother liquor kept warm under the stirring.

Subsequently, 320 ml of an NH ₄ F aqueous solution (2.5 mol / l) was prepared, and a precision cylinder pump was placed in a mixing chamber in the reaction mother liquor containing the suspension, which was kept warm under the above stirring. Was used at an addition rate of 8 ml / min 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
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 (BaFBr: 0.001Eu ²⁺ ).

Comparative Example 1 NH ₄ was synthesized to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide.
1780 ml of Br aqueous solution (4.5 mol / l) and E
5 ml of an aqueous uBr ₃ solution (0.2 mol / l) and water 2
15 ml of the reaction mother liquor (NH ₄ Br concentration: 4.0)
Mol / l) into a 4 liter 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
00 ml and BaBr ₂ aqueous solution (2.5 mol / l)
And 400 ml separately. Using a separate precision cylinder pump, 10 ml of an aqueous NH ₄ F solution was added to the mixing chamber in the reaction mother liquor, which was kept warm under the above stirring, so that the molar ratio between NH ₄ F and BaBr ₂ became constant. /
And an aqueous solution of BaBr ₂ were added at an addition rate of 40 ml / min 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
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 (BaFBr: 0.001Eu ²⁺ ).

Comparative Example 2 NH ₄ was synthesized to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide.
220 ml of Br aqueous solution (4.5 mol / l) and Eu
5 ml of an aqueous solution of Br ₃ (0.2 mol / l) and BaB
r ₂ aqueous solution (2.5 mol / liter) 480 ml of water 1
295 ml of the reaction mother liquor (NH ₄ Br concentration: 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
00 ml and BaBr ₂ aqueous solution (2.5 mol / l)
And 400 ml separately. Using a separate precision cylinder pump, 2 ml of an aqueous NH ₄ F solution was added to a mixing chamber in the reaction mother liquor kept warm under the above stirring so that the molar ratio between NH ₄ F and BaBr ₂ was constant. / Min,
An aqueous solution of BaBr ₂ was added at an addition rate of 8 ml / min 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
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 (BaFBr: 0.001Eu ²⁺ ).

The stimulable phosphors obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were evaluated as follows. [Measurement of Phosphor Particle Shape and the Like] The particle size (median diameter) and the particle size distribution were measured using a light diffraction type particle size distribution measuring device (LA-50 manufactured by Horiba, Ltd.).
0). As the median diameter, a value measured by the above apparatus was used, and the particle size distribution was calculated from a distribution table measured by the above apparatus (FIGS. 4 and 5). The particle shape and the particle aspect ratio were evaluated using a scanning electron microscope (JSM-5400LV, manufactured by JEOL Ltd.). The average value was obtained by actually measuring the aspect ratio of 200 points of the particles of the photograph obtained by the above apparatus, and the average value was calculated. Table 1 shows the evaluation results.

Next, in Examples 1 to 4 and Comparative Examples 1 and 2,
Using the resulting stimulable phosphor, a radiation image conversion panel
It was prepared according to the following procedure and evaluated as follows. Example 1
To 4 and Comparative Examples 1 and 2 (BaFBr:
0.001Eu ²⁺), 356 g, polyurethane resin (Sumitomo)
Bayer Urethane Co., Ltd., “Desmolak 4125”
15.8 g, bisphenol A type epoxy resin 2.0 g
To a mixed solvent of methyl ethyl ketone-toluene (1: 1)
And dispersed using a propeller mixer, having a viscosity of 25-
A 30 PS phosphor layer coating solution was prepared. This phosphor layer
Using a doctor blade to apply
After coating on ethylene terephthalate film, 1
After drying at 00 ° C for 15 minutes, phosphor layers of various thicknesses
Formed.

Next, a fluorine-based resin (fluoroolefin-
Vinyl ether copolymer: 70 g of "Lumiflon LF-100" manufactured by Asahi Glass Co., Ltd.), a crosslinking agent (isocyanate:
Sumitomo Bayer Urethane Co., Ltd., “Death Module Z4
370 ") 25 g, bisphenol A type epoxy resin 5
g, and 10 g of silicone resin powder (particle size: 1-2 μm: “KMP-590” manufactured by Shin-Etsu Chemical Co., Ltd.) are added to a mixed solvent of toluene-isopropyl alcohol (1: 1), and the coating solution for the protective layer is added. Prepared. This protective layer coating solution is applied on a phosphor layer which has been formed in advance using a doctor blade, and then heat-treated at 120 ° C. for 30 minutes to be thermally cured and dried, and the protective layer having a thickness of 10 μm is formed. Was provided. By the method described above, radiation image conversion panels having stimulable phosphor layers of various thicknesses were obtained.

[Evaluation Method of Radiation Image Conversion Panel] <Evaluation of Sensitivity> The irradiated radiation image conversion panel was irradiated with X-rays having a tube voltage of 80 kV, and then scanned with a He-Ne laser beam (wavelength: 632.8 nm). Then, the photostimulated luminescence intensity emitted from the phosphor layer was measured, and the sensitivity was evaluated using the photostimulated luminescence intensity. evaluated.). <Evaluation of Sharpness> X-rays having a tube voltage of 80 kV were applied to the produced radiation image conversion panel through a CTF chart and then scanned with a He-Ne laser beam to obtain an image of a CTF chart. A contrast transfer function (CTF) was measured from the obtained image, and evaluated by a CTF value at a spatial frequency of 2 cycles / mm. <Granularity> A tube voltage of 80 was applied to the produced radiation image conversion panel.
After uniform irradiation with kV X-rays, scanning was performed with a He-Ne laser beam to obtain a uniform exposure image. The graininess of the obtained image signal was evaluated using the RMS value (the RMS value indicated by the panel of Example 1 was set to 100 and the graininess was relatively evaluated). Table 1 shows the evaluation results.

[0080]

[Table 1]

From the results shown in Table 1, in Examples 1 to 4 in which the crystal nuclei of the phosphor precursor crystals were first formed using the instantaneous reaction apparatus and then the crystals were further grown in the reactor, the particle aspect ratio was reduced. While the controllability of the particle size distribution was good in the tetrahedral particles near 1, the particle shape in Comparative Example 1 was columnar. In Comparative Example 2, although the particle shape was a tetrahedral shape, the particle size distribution was broad at 50% or more. The image quality of the radiation image conversion panel made of the phosphors of Examples 1 to 4 is good in the balance between sensitivity, sharpness and granularity, while Comparative Examples 1 and 2
The panel image quality tended to be poor in sharpness and graininess.

[0082]

According to the method for producing a stimulable phosphor of the present invention, since the number of particles is determined by forming crystal nuclei of the phosphor precursor crystals, the particle shape and particle aspect of the phosphor particles obtained are determined. The ratio, particle size (median diameter), and particle size distribution can be easily controlled. For example, when used in a radiation image conversion panel or the like, image quality (particularly sharpness or structural noise)
Can be provided. Further, according to the reaction device of the present invention, the stimulable phosphor as described above can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of the reaction apparatus of the present invention.

FIG. 2 is a schematic diagram showing an example of an instantaneous reaction device included in the reaction device of the present invention.

FIG. 3 is a diagram showing an example of a shape of a stirrer used in the instant reaction device.

FIG. 4 is a particle size distribution table of phosphor particles obtained in Examples and Comparative Examples.

FIG. 5 is a graph showing a particle size distribution of phosphor particles obtained in Examples and Comparative Examples.

FIG. 6 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 of the stimulable phosphor layer in the stimulable phosphor layer. It is a figure which shows the direction of light conduction typically.

FIG. 7 is a diagram schematically showing the arrangement of rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphors in the phosphor layer of the radiation image conversion panel and the direction of photoconductivity in the phosphor layer. It is.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Reaction device 101 Precision cylinder pump 102 Precision cylinder pump 103 Precision cylinder pump 104 First reaction liquid 105 Second reaction liquid 106 Carrier liquid 107 Instantaneous reaction device 108 Stirring means 109 Stirring means 110 Switching valve 111 Switching valve 112 Temperature controller 113 reactor 114 mixing chamber 115 stirring motor 116 stirring blade 200 instantaneous reaction device 201 stirring means 202 stirring means 203 reaction cell 204 stirrer 205 stirrer A first reaction liquid inlet B carrier liquid inlet C second reaction liquid inlet D Suspension outlet

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G21K 4/00 G21K 4/00 MF term (reference) 2G083 AA03 BB01 CC10 DD02 DD11 DD12 DD14 DD15 DD17 EE02 EE03 4G076 AA04 AC02 BA15 BA38 BA43 BB04 BC02 BD02 CA26 CA29 DA30 4H001 CA04 CF02 XA09 XA17 XA20 XA35 XA38 XA53 XA56 YA03 YA11 YA19 YA37 YA55 YA58 YA59 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, NH ₄ X; a water-soluble compound of Ln; the above basic composition formula (I)
If x in formula (I) is not 0, then halide, nitrate, nitrite or acetate of M ^II ;
Halides y is more M ^I when non-zero, nitrate, nitrite or acetate; an aqueous solution containing,
In addition, a reaction mother liquor having an NH ₄ X concentration of 2.0 mol / L or more and 4.5 mol / L or less after dissolving them is prepared, and the reaction mother liquor is maintained at a temperature of 20 to 100 ° C. and stirred. A mother liquor preparation step, and an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are stirred at a high speed while being added to form crystal nuclei of phosphor precursor crystals. a crystal nucleus forming step of introducing into the reaction mother liquor being stirred and maintained at a temperature, while maintaining the reaction mother liquor containing the suspension to a temperature of 20 to 100 ° C., this BaX ₂ aqueous solution and inorganic fluoride Simultaneously with an aqueous solution of a salt, and fluorine of inorganic fluoride salt and BaX
A precipitate forming step of adding a phosphor precursor crystal precipitate to be added so as to maintain a constant molar ratio of _2, and a separation step of separating the precipitate of the phosphor precursor crystal from an aqueous solution; A sintering step of firing the separated precipitate of the phosphor precursor crystal while avoiding sintering, a method for producing a rare earth-activated alkaline earth metal fluoride halide 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 ;
Halides y is more M ^I when non-zero, nitrate, nitrite or acetate; an aqueous solution containing,
And, when the BaX ₂ concentration after dissolving them, X is Cl
Or 2.5 mol / liter or less for Br, and X is I
In the case of the above, a mother liquor of 5.0 mol / liter or less is prepared, the mother liquor is prepared at a temperature of 20 to 100 ° C. and stirred, and an aqueous solution of inorganic fluoride salt and an aqueous solution of BaX ₂ are prepared. Is added at a high speed to form crystal nuclei of phosphor precursor crystals, and the reacted suspension is maintained at the temperature of 20 to 100 ° C. and introduced into the stirred mother liquor. And a step of forming a precipitate of phosphor precursor crystals by adding an aqueous solution of an inorganic fluoride salt thereto while maintaining the reaction mother liquor containing the suspension at a temperature of 20 to 100 ° C. 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. Rare earth activated alkaline earth metal fluoride Method of manufacturing the Gen monster stimulable phosphor. 3. The method of claim 1, wherein the inorganic fluoride salt is used 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
2. The method according to claim 1, wherein an aqueous solution of
Rare earth activated alkaline earth metal fluorinated halide photostimulability
A method for producing a phosphor. 4. A phosphor precursor formed during the addition of an aqueous solution of an inorganic fluoride salt in a precipitate formation step, where 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
The rare earth activated alkaline earth metal fluoride halide stimulant according to claim 2, wherein the inorganic fluoride salt aqueous solution is added by adjusting the addition rate so as to be in the range of N / min. A method for producing a phosphor. 5. An inorganic fluoride salt in a crystal nucleation step.
Aqueous solution and BaX _TwoWhen an aqueous solution of
Of the precipitate of phosphor precursor crystals finally obtained in the synthesis process
When the amount is N, before the phosphor in the crystal nucleation step
The amount of crystal nuclei of precursor crystals is greater than 0N and 0.8N or less
An aqueous solution of an inorganic fluoride salt and B
aX_Two2. The method according to claim 1, wherein an aqueous solution of
The rare earth activated alkaline earth gold according to any one of the chairs 4
A method for producing a fluorinated fluorinated phosphor of the genus group. 6. 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. 7. The method according to claim 1, wherein in the crystal nucleus forming step, an aqueous solution of an inorganic fluoride salt and an aqueous solution of BaX ₂ are stirred at a high speed using an instantaneous reaction apparatus. For producing a rare earth activated alkaline earth metal fluorinated halide based stimulable phosphor. 8. Two or more liquid applicators for accommodating and sending the liquid to the outside, and the liquids sent from the two or more liquid applicators are accommodated inside, stirred at a high speed, and then sent to the outside. An instant reaction device to be sent out; and a stirring tank containing the solution sent out from the two or more liquid adders and the solution sent out from the instantaneous reaction device and stirring it together with a reaction mother liquor previously housed therein. A reaction device comprising: