JPH10195431A - Rare earth-activated rare earth metallic fluorohalide-based stimulable fluorescent substance, its production and radiation image-converting panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a rare earth-activated rare earth metallic fluorohalide- based stimulable fluorescent substance, having high sensitivity, excellent in image characteristics and suitable for a radiation image-converting panel, etc., by providing the fluorescent substance with a specific chemical composition. SOLUTION: This fluorescent substance is represented by the formula [M<2> is Mg, Ca, Sr, Zn or Cd; M<1> is Li, Na, K, Rb or Cs; X is Cl, Br, F or I; Ln is Ce, Pr, Sm, Eu, Gd, Tb, Tm, Dy, Ho, Nd, Er or Yb; (x), (y) and (z) are each 0<=(x)<=0.5; 0<=(y)<=0.05; 0<(z)<=0.2; (a) is -0.5<=(a)<=0.5] and is obtained by a liquid-phase method for using a solution containing BaX2 in an amount of >=30% of the solubility of a solvent for the BaX2 dissolved therein. The solvent is preferably other than water and is preferably an alcohol-based solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor, a method for producing the stimulable phosphor, and a radiation image using the stimulable phosphor. It relates to a conversion panel.

[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 radiation having a much smaller amount of exposure and a richer amount of information than a conventional radiographic method using a combination of a radiographic film and an intensifying screen. There is an advantage that an image can be obtained. Furthermore, the conventional radiographic method consumes radiographic film for each photographing operation, whereas the radiographic image conversion method uses a radiographic image conversion panel repeatedly, so that resource conservation and economic efficiency are also reduced. It is advantageous.

A stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then with excitation light. However, in practice, the stimulable phosphor has a wavelength of 400 to 900 nm due to the excitation light. Phosphors that exhibit stimulated emission in the 500 nm wavelength range are commonly used.

The radiation image conversion panel used in the radiation image recording / reproducing method has, as a basic structure, a support and a phosphor layer (stimulable phosphor layer) provided on the surface of the support. However, when the 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, as the stimulable phosphor layer, a layer composed of only an aggregate of the stimulable phosphor without a binder formed by a vapor deposition method or a sintering method is known.

There is also known a radiation image conversion panel having a stimulable phosphor layer impregnated with a polymer substance in a gap between stimulable phosphor aggregates. In any of these 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 emitted from the specimen is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and a radiation image of the subject or the subject is formed on the panel as an accumulated image of 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. Is protected from chemical alteration or physical impact.

Examples of stimulable phosphors conventionally used in radiation image conversion panels are: (1) Japanese Patent Application Laid-Open No. 55-12145 (Ba _1-X , M ²⁺ _X ) FX: yA (however, M ²⁺
Is at least one of Mg, Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
At least one of Nd, Yb, and Er, and x is 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.2). Metal fluorinated metal halide phosphors; the phosphors may also contain the following additives:
X ', Be described in Japanese Patent No. 74175
X ″, M ³ X ″ ″ ₃ (where X ′, X ″, and X ′ ″ are each at least one of Cl, Br and I, and M ³ is a trivalent metal);

[0009] BeO, BgO, CaO, SrO, BaO, Z described in JP-A-55-160078.
nO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In
₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , GeO ₂ , S
Metal oxides such as nO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ and ThO ₂ ; Zr and Sc described in JP-A-56-116777; described in JP-A-57-23673. B; As, Si described in JP-A-57-23675;

ML described in JP-A-58-206678 (where M is Li, Na, K, Rb,
And L is Sc, Y, La, Ce, Pr, or at least one alkali metal selected from the group consisting of
Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, T
m, Yb, Lu, Al, Ga, In, and at least one trivalent metal selected from the group consisting of Tl);
A calcined product of a tetrafluoroborate compound described in JP-A-59-27980;
No. 9; a calcined product of a salt of a monovalent or divalent metal of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid;
NaX 'described in JP-A-6479 (provided that
X ′ is at least one of Cl, Br and I); transition metals such as V, Cr, Mn, Fe, Co and Ni described in JP-A-59-56480;

M ¹ X ′, M ′ ² X ″, M ³ X ″ ″, A described in JP-A-59-75200 (where M ¹ is Li, Na, K, Rb, and at least one alkali metal selected from the group consisting of Cs, M ^'2 is at least one trivalent metal selected from the group consisting of be and Mg; M ³ is Al, Ga, I
X is at least one trivalent metal selected from the group consisting of n and Tl; A is a metal oxide;
X '' and X '''each F, Cl, at least one halogen selected from the group consisting of Br and I); ^M 1 X that are described in JP 60-101173 Laid' (although , M ¹ is at least one alkali metal selected from the group consisting of Rb and Cs;
X 'is at least one halogen selected from the group consisting of F, Cl, Br and I);

[0012] ^M 2 are described in ^{_{JP-A-61-23679 'X' 2 · M 2}} 'X''2 ( ^{however, M} 2'
Is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X 'and X' are each at least one halogen selected from the group consisting of Cl, Br and I; '≠ X''); and LnX'' ₃ described in Japanese Patent Application No. 60-106752 (where Ln is Sc, Y,
La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, D
X is at least one rare earth element selected from the group consisting of y, Ho, Er, Tm, Yb and Lu; X "is at least one halogen selected from the group consisting of F, Cl, Br and I); (2) JP-60-84381 Patent ^M 2 _X as described in JP _{^{2 · aM 2 '2: xEu}} 2+ ( However, ^{M 2} is B
X and X 'are Cl, at least one alkaline earth metal selected from the group consisting of a, Sr and Ca;
At least one halogen selected from the group consisting of Br and I and X ≠ X ′; and a is 0.1 ≦ a ≦ 0.0 and x is 0 <x ≦ 0.2) A divalent europium-activated alkaline earth metal halide phosphor represented by the following composition formula:

The phosphor may contain the following additives; M ¹ X ″ described in JP-A-60-166379 (where M ¹ is Rb
And Xs is at least one halogen selected from the group consisting of F, Cl, Br and I); Japanese Patent Application Laid-Open No. Sho 60-221483. the listed ^{_{KX '', MgX '''}} 2, M 3 X''''3 ( however, ^{M 3} is Sc, Y, La, at least one trivalent metal selected from the group consisting of Gd and Lu Yes;
X ", X""andX""" are all F, C
l, is at least one halogen selected from the group consisting of Br and I); JP 60-228592 Patent are described in JP-B; JP _SiO 2 as described in 60-228593, JP- P ₂ O ₅ oxide such; are described in JP 61-120882 Laid Li
X ", NaX" (where X "is F, Cl, Br
And at least one halogen selected from the group consisting of I); SiO disclosed in JP 61-120883 JP; SnX are described in JP 61-120885 Laid _{'' 2} (where , X ″ are F, C
at least one halogen selected from the group consisting of l, Br and I);

CsX ″ and SnX ″ ″ ₂ (provided that X ″ is described in JP-A-61-235486)
And X '''' are each at least one halogen selected from the group consisting of F, Cl, Br and I); and CsX '', Ln ³⁺ described in JP-A-61-235487. , X ″ is F,
Ln is at least one halogen selected from the group consisting of Cl, Br and I; Ln is Sc, Y, Ce, Pr,
Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Y
at least one rare earth element selected from the group consisting of b and Lu);

(3) LnOX: xA described in JP-A-55-12144 (where Ln is La,
At least one of Y, Gd, and Lu; X is C
at least one of l, Br, and I; A is at least one of Ce and Tb; and x is 0 <x
<0.1), a rare earth element activated rare earth oxyhalide phosphor represented by a composition formula:

(4) M ³ OX: xCe described in JP-A-58-69281 (where M ³ is Pr,
Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, T
at least one metal oxide selected from the group consisting of m, Yb, and Bi; X is at least one of Cl, Br, and I; and x is 0 <x <0.1). A cerium-activated trivalent metal oxyhalide phosphor represented by the formula:

(5) M ¹ X: xBi described in Japanese Patent Application No. 60-70484 (where M ¹ is at least one alkali metal selected from the group consisting of Rb and Cs); At least one halogen selected from the group consisting of Cl, Br and I; and x
Is a numerical value in the range of 0 <x ≦ 0.2) bismuth-activated alkali metal halide phosphor represented by a composition formula;

[0018] ^{_{(6) M 2 5 (PO}} 4) as described in JP 60-141783 discloses 3 x: at least one ^{xEu 2+} (However, ^{M 2} is selected from the group consisting of Ca, Sr and Ba X is at least one halogen selected from the group consisting of F, Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2). A divalent europium activated alkaline earth metal halophosphate phosphor represented by:

[0019] (7) ^M _{2 2 BO} 3 that is described in JP 60-157099 discloses X: ^{xEu 2+} (where
M ² is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is Cl, B
at least one halogen selected from the group consisting of r and I; x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal haloborate represented by the composition formula: Phosphor;

[0020] (8) ^M _{2 2 PO} 4 as described in JP 60-157100 discloses X: ^{xEu 2+} (where
M ² is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is Cl, B
at least one halogen selected from the group consisting of r and I; x is a numerical value in the range of 0 <x ≦ 0.2) divalent europium-activated alkaline earth metal halophosphate represented by a composition formula: Phosphor;

(9) M ² HX: xEu ²⁺ described in JP-A-60-217354 (where M ² is at least one kind of alkaline earth metal selected from the group consisting of Ca, Sr and Ba) X is at least one halogen selected from the group consisting of Cl, Br and I; x is a numerical value in the range of 0 <x ≦ 0.2) Earth metal hydride halide phosphors;

[0022] (10) _LnX as described in JP 61-21173 discloses 3 _· aLn'X '3: ^{xCe 3+}
(However, Ln and Ln ′ are Y, La, and Gd, respectively.
X and X ′ are F, Cl, B, respectively, at least one rare earth element selected from the group consisting of
at least one halogen selected from the group consisting of r and I, and X ≠ X ′;
It is a numerical value in the range of 1 <a ≦ 10.0, and x is 0 <x ≦
A cerium-activated rare earth composite halide phosphor represented by a composition formula:

[0023] (11) JP-61-21182 JP _LnX 3 ^· aM 1 that is described in X ': ^{xCe 3+} (However, Ln and Ln', respectively Y, La, selected from the group consisting of Gd and Lu Is at least one rare earth element; M ¹ is at least one alkali metal selected from the group consisting of Li, Na, K, Cs and Rb; X and X ′ are each a group consisting of Cl, Br and I At least one halogen selected;
And a is a numerical value in the range of 0 <a ≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2), a cerium-activated rare earth composite halide phosphor represented by a composition formula;

(12) LnPO ₄ .aLnX ₃ : xCe described in JP-A-61-40390
³⁺ (where Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu;
X is at least one halogen selected from the group consisting of F, Cl, Br and I; and a is 0.1 ≦ a
≦ 10.0, x is a numerical value in the range of 0 <x ≦ 0.2) cerium-activated rare earth halophosphate phosphor represented by the composition formula;

(13) CsX: aRbX ': xEu ²⁺ described in Japanese Patent Application No. 60-78151 (where X and X' are at least one member selected from the group consisting of Cl, Br and I, respectively) Halogen;
And a is a numerical value in the range of 0 <a ≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2). Divalent europium-activated cesium rubidium halide fluorescence represented by the composition formula: Body; and

(14) M ² X ₂ .aM ¹ X ': xEu described in Japanese Patent Application No. 60-78153
²⁺ (where M ² is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; M ¹ is at least one alkali metal selected from the group consisting of Li, Rb and Cs; X and X '
Is at least one halogen each selected from the group consisting of Cl, Br and I; and a is 0.1 ≦
a is a numerical value in the range of a ≦ 20.0, and x is 0 <x ≦ 0.2
And a divalent europium-activated composite halide phosphor represented by the following composition formula:

Among the above-described stimulable phosphors, iodine-containing divalent europium-activated alkaline earth metal fluorohalide-based phosphors and iodine-containing divalent europium-activated alkaline earth metal halides The iodine-containing rare earth element-activated rare earth oxyhalide-based phosphor and the iodine-containing bismuth-activated alkali metal halide-based phosphor exhibit high luminance stimulable luminescence.

The method for producing these stimulable phosphors conventionally known is a solid phase method or a sintering method. However, pulverization after firing is indispensable, and affects image performance such as sensitivity. There is a problem that it is difficult to control the particle shape.

[0029]

The present invention relates to a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor, a method for producing the same, and a radiation image conversion panel, and in particular, image characteristics represented by sensitivity. It is an object of the present invention to provide a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor excellent in the above, a production method thereof, and a radiation image conversion panel.

[0030]

The object, according to an aspect of the (1) formula ^{_{(1) Ba 1-x M}} 2 xF 1-a X 1 + a: yM 1, zLn M 2: Mg, Ca, Sr, Zn and Cd At least one kind of alkaline earth metal selected from the group consisting of: M ¹ : at least one kind of alkali metal selected from the group consisting of Li, Na, K, Rb and Cs X: selected from the group consisting of Cl, Br, F and I At least one halogen Ln: Ce, Pr, Sm, Eu, Gd, Tb, Tm, D
at least one rare earth element x, y and z selected from the group consisting of y, Ho, Nd, Er and Yb is 0 ≦ x ≦ 0.5, 0 ≦ y ≦
0.05,0 <z ≦ 0.2, -0.5 is ≦ a ≦ 0.5 phosphor represented by a liquid to use a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ is dissolved A rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor obtained by a phase method.

(2) The rare earth-activated alkaline earth metal fluoride halide stimulable phosphor according to claim 1, wherein the solvent is a solvent other than water.

(3) The rare earth-activated alkaline earth metal fluoride halide stimulable phosphor according to claim 2, wherein the solvent is an alcohol.

(4) A rare earth activated alkaline earth metal having the following steps for producing the rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor according to claim 1, 2 or 3. A method for producing a fluorinated halide stimulable phosphor.

Containing BaX ₂ and a halide of Ln,
When x in the general formula (1) is not 0, M ²
And, if y is not 0, further M
Includes ^one halide, after which they are dissolved in a solvent, more than 30% Ba solubility of solvent to BaX ₂
Preparing a solution in which X ₂ is dissolved; above solution 50
A solution of an inorganic fluoride (ammonium fluoride or a fluoride of an alkali metal) is added to the solution while maintaining the temperature at a temperature of not less than ° C. to prepare a rare earth activated alkaline earth metal fluoride halide stimulable phosphor precursor. Obtaining a crystalline precipitate; separating the precursor crystal precipitate from the solution; and firing the separated precursor crystal precipitate while avoiding sintering.

(5) A rare earth activated alkaline earth metal having the following steps for producing the rare earth activated alkaline earth metal fluorohalide stimulable phosphor according to claim 1, 2 or 3. A method for producing a fluorinated halide stimulable phosphor.

The mother liquor comprises and a halide of ammonium halide and Ln, and further in the case x in the general formula (1) is not zero, a halide of M ^2, and y is 0
If not, further comprising a halide of M ¹ , after they are dissolved in a solvent, preparing an ammonium halide solution; maintaining said solution at a temperature of 50 ° C. or higher while adding inorganic fluoride ( A rare earth-activated alkaline earth metal fluoride by continuously or intermittently adding a solution of ammonium fluoride or an alkali metal fluoride) and a solution of BaX _{2 having} a solubility of 30% or more of the solvent in BaX _2. Obtaining a precipitate of a halide-based stimulable phosphor precursor crystal; separating the precursor crystal precipitate from a solution; and firing the separated precursor crystal precipitate while avoiding sintering. .

(6) A rare earth activated alkaline earth metal having the following steps for producing the rare earth activated alkaline earth metal fluorohalide stimulable phosphor according to claim 1, 2 or 3. A method for producing a fluorinated halide stimulable phosphor.

The mother liquor contains BaX ₂ and x of the general formula (1)
Further contains a halide of M ² if y is not 0, and further contains a halide of M ¹ if y is not 0, after they are dissolved in the solvent, at least 30% of the solubility of the solvent in BaX ₂ Preparing a solution in which BaX ₂ is dissolved; while maintaining the above solution at a temperature of 50 ° C. or higher, a solution of an inorganic fluoride (a fluoride of ammonium or an alkali metal) and a halide of Ln are added. Adding a solution to obtain a precipitate of rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystals; separating the precursor crystal precipitate from the solution; and separating Baking the precursor crystal precipitate while avoiding sintering.

(7) A rare earth activated alkaline earth metal having the following steps for producing the rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor according to claim 1, 2 or 3. A method for producing a fluorinated halide stimulable phosphor.

The mother liquor contains BaX ₂ and x of the general formula (1)
Further in the case but not 0, the halide of M ^2, and further comprises a halide of M ¹ when y is not 0, then they were dissolved in a solvent, preparing a ammonium halide solution; the while maintaining the solution temperature above 50 ° C. and to this solution of an inorganic fluoride (ammonium fluoride or alkali metal fluoride), a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ was dissolved, And a solution of the halide of Ln with fluorine, Ba and L
a step of continuously or intermittently adding while maintaining the ratio of n to obtain a precipitate of a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystal; Separating the precipitate from the solution; and firing the separated precursor crystal precipitate while avoiding sintering.

(8) The method for producing a rare earth-activated alkaline earth metal fluorinated halide stimulable phosphor according to claim 5 or 7, wherein the alkaline earth metal fluorinated halide stimulable phosphor is used. Prior to the formation of the phosphor precursor crystal precipitate, L
A method for producing a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor, comprising adding a halide of Ln after forming a precursor crystal precipitate without adding a halide of n.

(9) In a radiation image conversion panel having a phosphor layer containing a stimulable phosphor, the rare earth activated alkaline earth metal fluorinated halide according to claim 1, 2 or 3 is used. A radiation image conversion panel comprising a depleted phosphor.

Each of the above is solved.

Here, the solubility of the solvent in BaX ₂ is 3
The liquid phase method using a solution in which 0% or more of BaX ₂ is dissolved means that, for example, when water is a solvent, 14.9 g or more, which is 30% of 49.5 (20 ° C.) the solubility of water in BaBr ₂ is water. This means that a dissolved aqueous solution is used.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION The production of a rare earth-activated alkaline earth metal fluoride halide stimulable phosphor represented by the above general formula (1) is not a solid phase method in which control of particle shape is difficult, but a particle size. Was carried out by a liquid phase method, which is easy to control. In particular, it is preferable to obtain a stimulable phosphor by the following two liquid phase synthesis methods.

Production method 1: When the compound contains BaX ₂ and a halide of Ln and x in the general formula (1) is not 0, M
² halide, and y include 0 non Furthermore halide of M ¹ in the case, after which they are dissolved in a solvent, more than 30% Ba solubility of solvent to BaX ₂
Preparing a solution in which X ₂ is dissolved; above solution 50
While maintaining the temperature at a temperature of not less than 60 ° C, preferably at a concentration of 0.5N or more, preferably 1.0
A step of adding a solution of N or more inorganic fluoride (ammonium fluoride or alkali metal fluoride) to obtain a precipitate of a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor precursor crystal; By preparing a precipitate of a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystal under the above conditions, high purity of the crystal is achieved, and the radiation image conversion produced by the crystal is achieved. The panel sensitivity was improved.

A manufacturing method comprising the steps of separating the above-mentioned precursor crystal precipitate from a solution; and firing the separated precursor crystal precipitate while avoiding sintering.

[0048] Process 2: When the mother liquor contains a halide of ammonium halide and Ln, further when x in the general formula (1) is not 0, a halide of M ^2, and y is not 0 A step of preparing a solution containing a halide of M ^{1 and having} a concentration of ammonium halide of 3N or more, preferably 4N or more after dissolving in a solvent;
A solution of an inorganic fluoride (ammonium fluoride or alkali metal fluoride) having a concentration of 0.5 N or more, preferably 1.0 N or more, while maintaining the temperature at 0 ° C. or more,
Precipitation of rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystal by continuously or intermittently adding a solution in which BaX ₂ having a solubility of 30% or more of the solvent to X ₂ is dissolved. A step of obtaining a product; by preparing a precipitate of a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystal under the above conditions, high purity of the crystal is achieved, and The sensitivity of the manufactured radiation image conversion panel was improved.

A process comprising the steps of separating the above-mentioned precursor crystal precipitate from a solution; and firing the separated precursor crystal precipitate while avoiding sintering.

Regardless of the timing of addition of the halide of Ln, it may be present in the reaction mother liquor or the like at the start of addition, or may be a solution of an inorganic fluoride (ammonium fluoride or an alkali metal fluoride) and BaX. The solution may be added at the same time or after the addition of the _second solution.

The rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor of the present invention has an average particle size of 0.5-2.
It is preferably 0.0 μm, more preferably 1 to 10 μm. Here, the average particle diameter is obtained by randomly selecting 200 particles from an electron micrograph of the particles (crystals) and calculating the average by a sphere-equivalent volume particle diameter.

[0052] By using the solution of BaX ₂ of more than 30% of the solubility of the solvent to BaX _2, not only the solvent species used, has become possible to produce the stimulable phosphor. Although the details of the mechanism are not clear, increasing the concentration increases the number of solvent molecules bound to the ion, driving the binding, the physical and chemical properties of the generated species (steric structure, mobility , Reaction rate, etc.), it can be considered that the following reaction has progressed, but it is not always clear. BaX ₂ + NH ₄ F → BaFX + NH ₄ X The particles (crystals) according to the present invention are preferably monodisperse, and the average particle size distribution (%) is preferably 20% or less, particularly preferably 15% or less. Things are good.

Hereinafter, the method for producing the stimulable phosphor will be described in detail. An example in which an alcohol solvent is mainly used will be described.

(Preparation of Precipitate Crystal Precipitate, Preparation of Stimulable Phosphor) First, a raw material compound other than a fluorine compound is dissolved using an alcohol-based medium (solvent). That is, B
aX ₂ and a halide of Ln, and optionally further M
² halide, and further mixed sufficiently put halide of M ¹ in alcoholic medium, is dissolved, to prepare them dissolved solution. However, so that a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ is dissolved in advance by adjusting the quantitative ratio between the BaX ₂ concentration and an alcoholic solvent. At this time, a small amount of an acid, ammonia, a polymer, or the like may be added, if desired. This solution (reaction mother liquor) is maintained at a constant temperature of 50 ° C. or higher.

Next, a solution of inorganic fluoride (ammonium fluoride, alkali metal fluoride, etc.) is added to the stirred solution maintained at a constant temperature of 50 ° C. or higher by using a pipe with a pump or the like. inject. This injection is preferably carried out in the region where the stirring is particularly violent. By injecting this inorganic fluoride solution into the reaction mother liquor,
A rare earth activated alkaline earth metal fluorohalide-based phosphor precursor crystal corresponding to the general formula (1) precipitates.

Next, the above phosphor precursor crystals are filtered,
The solution is separated from the solution by centrifugation, washed thoroughly with methanol or the like, and dried. A sintering inhibitor such as alumina fine powder or silica fine powder is added to and mixed with the dried phosphor precursor crystal to uniformly adhere the sintering inhibitor fine powder to the crystal surface. The addition of the sintering inhibitor can be omitted by selecting the firing conditions.

Next, the crystal of the phosphor precursor is filled in a heat-resistant container such as a quartz port, an alumina crucible, or a quartz crucible, and is placed in a furnace of an electric furnace and sintered while avoiding sintering. The firing temperature is suitably in the range of 400 to 1300C, and preferably in the range of 500 to 1000C. The firing time varies depending on the filling amount of the phosphor raw material mixture, the firing temperature, the temperature of taking out from the furnace, and the like.
12 hours is appropriate.

The firing atmosphere may be a neutral atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere, or 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 the like. A trace oxygen introduction atmosphere is used.

By the above calcination, the desired rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor is obtained.

The rare earth activated alkaline earth metal fluoride halide stimulable phosphor represented by the general formula (1) of the present invention is, as described above, an ammonium halide (NH ₄ B).
r or NH ₄ Cl or NH ₄ I) and a halide of Ln, and further, when x in formula (1) is not 0, further a halide of M ² , and when y is not 0, It further contains the halides of M ¹ , after they are dissolved in the solvent, the solubility of the solvent in BaX _{2 is} reduced to 30%.
% Of BaX ₂ dissolved in the solution, while maintaining the solution at a constant temperature of 50 ° C. or more, the solution of inorganic fluoride and the solution of BaX ₂ are mixed with the former fluorine and the latter Ba. Obtaining a precipitate of rare earth-activated alkaline earth metal fluorohalide-based phosphor precursor crystals by adding continuously or intermittently while maintaining the ratio of It can also be produced using a production method (production method 2) comprising a step of separating; and a step of firing the separated precursor crystal precipitate while avoiding sintering.

Next, this manufacturing method will be described in detail. First, a raw material compound excluding BaX ₂ and a fluorine compound using an alcohol-based medium, and an ammonium halide (N
Dissolve H ₄ Br or NH ₄ Cl or NH ₄ I). Namely, a halide of ammonium halide and Ln, and further halide of M ² if necessary, and further a halide of M ¹ and mixed thoroughly placed in alcoholic medium, is dissolved, they in an alcohol solvent Prepare a dissolved solution. However, such a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ is dissolved in advance by adjusting the quantitative ratio of the ammonium halide and an alcohol solvent. At this time, if desired,
A small amount of acid, ammonium, high-molecular polymer, etc. may be added. This solution (reaction mother liquor) is maintained at 50 ° C.

Next, maintained at this 50 ° C., to the stirred solution, an inorganic fluoride with a solution of the solution and BaX ₂ of (ammonium fluoride, alkali metal fluoride, etc.) at the same time, the inorganic fluoride The injection is carried out continuously or intermittently using a pipe with a pump or the like while adjusting the ratio of fluorine and the latter BaX ₂ to be constant. This injection is preferably carried out in the region where the stirring is particularly violent. Thus, during the phosphor crystal formation, Ba
By proceeding the reaction while taking care not to make the ions excessive, a rare earth activated alkaline earth metal fluorohalide-based phosphor precursor crystal corresponding to the basic composition formula (1) is precipitated.

Next, the phosphor precursor crystal is separated from the solvent, dried and calcined in the same manner as in the production method 1 to obtain the desired rare earth-activated alkaline earth metal fluoride halide. A stimulable phosphor is obtained. The solvent used in the present invention may be any of water and a solvent other than water, but an alcohol solvent is most preferred.

The solvent used in the present invention includes alcohols such as methanol, ethanol, 1-propanol and n-butanol; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate; And the like, and a mixture thereof may be used.

(Preparation of Panel, Phosphor Layer, Coating Step, Support, Protective Layer) As the support used in the radiation image conversion panel of the present invention, various polymer materials, glass, metal and the like are used. In particular, a material that can be processed into a flexible sheet or web on handling as an information recording material is preferable, and in this regard, a cellulose acetate film, a polyester film, a polyethylene terephthalate film, a polyamide film, a polyimide film, a triacetate film, Plastic film such as polycarbonate film, aluminum, iron,
A metal sheet such as copper or chromium or a metal sheet having a coating layer of the metal oxide is preferable.

The layer thickness of the support varies depending on the material of the support to be used and the like.
The thickness is more preferably 80 μm to 500 μm from the viewpoint of handling.

The surface of the support may be a smooth surface or a mat surface for the purpose of improving the adhesion to the stimulable phosphor layer.

Further, in these supports, an undercoat layer may be provided on the surface on which the stimulable phosphor layer is provided for the purpose of improving the adhesion to the stimulable phosphor layer.

Examples of the binder used in the stimulable phosphor layer in the present invention include proteins such as gelatin, polysaccharides such as dextran, and natural polymer substances such as gum arabic; and polyvinyl butyral, Vinyl acetate, nitrocellulose, ethylcellulose,
A binder represented by a synthetic polymer such as vinylidene chloride-vinyl chloride copolymer, polyalkyl (meth) acrylate, vinyl chloride-vinyl acetate copolymer, polyurethane, cellulose acetate butyrate, polyvinyl alcohol, linear polyester, etc. Can be mentioned.

Particularly preferred among such binders are nitrocellulose, linear polyester, polyalkyl (meth) acrylate, a mixture of nitrocellulose and linear polyester, nitrocellulose and polyalkyl (meth) acrylate. And a mixture of polyurethane and polyvinyl butyral. In addition, these binders may be cross-linked by a cross-linking agent. The stimulable phosphor layer can be formed on the undercoat layer by the following method, for example.

First, a stimulable phosphor, a compound such as a phosphite for preventing yellowing, and a binder are added to an appropriate solvent, and these are mixed well to obtain phosphor particles in a binder solution. And a coating liquid in which particles of the compound are uniformly dispersed is prepared.

Examples of the binder used in the present invention include proteins such as gelatin, polysaccharides such as dextran or gum arabic, polyvinyl butyral,
Polyvinyl acetate, nitrocellulose, ethyl cellulose, vinyl chloride / vinyl chloride copolymer, polymethyl methacrylate, vinyl chloride / vinyl acetate copolymer, polyurethane, cellulose acetate butyrate,
A film-forming binder usually used for a layer structure such as polyvinyl alcohol is used. Generally, the binder is used in an amount of 0.01 to 1 part by weight based on 1 part by weight of the stimulable phosphor. However, from the viewpoint of the sensitivity and sharpness of the obtained radiation image conversion panel, it is preferable that the amount of the binder is small, and the range of 0.03 to 0.2 part by weight is more preferable in consideration of the ease of application.

The mixing ratio between the binder and the stimulable phosphor in the coating solution (however, when the entire binder is an epoxy group-containing compound, the mixing ratio is equal to the ratio between the compound and the phosphor)
The characteristics of the target radiation image conversion panel, the type of phosphor,
Depends on the amount of epoxy group-containing compound added, etc.
In general, examples of the solvent for preparing the binding coating solution include: lower alcohols such as methanol, enotal, 1-propanol, 2-propanol and n-butanol; hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride; acetone, methyl ethyl ketone Ketones such as methyl isobutyl ketone; esters of lower fatty acids such as methyl acetate, ethyl acetate and butyl acetate with lower alcohols; dioxane, ethylene glycol ethyl ether,
Ethers such as ethylene glycol monomethyl ether; toluene; and mixtures thereof.

Examples of the solvent used for preparing the coating solution for the stimulable phosphor layer include lower alcohols such as methanol, ethanol, isopropanol and n-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and the like.
Ketones such as cyclohexanone, esters of lower fatty acids such as methyl acetate, ethyl acetate and n-butyl acetate with lower alcohols, dioxane, ethers such as ethylene glycol monoethyl ether and ethylene glycol monomethyl ether, aromatic compounds such as triols and xylol And halogenated hydrocarbons such as methylene chloride and ethylene chloride, and mixtures thereof.

The coating solution contains a dispersant for improving the dispersibility of the phosphor in the coating solution, and a dispersant between the binder and the phosphor in the stimulable phosphor layer after formation. Various additives such as a plasticizer for improving the bonding strength may be mixed. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, and lipophilic surfactants. Examples of the plasticizer include phosphoric esters such as triphenyl phosphate, tricresyl phosphate and diphenyl phosphate; phthalic esters such as diethyl phthalate and dimethoxyethyl phthalate; ethylphthalylethyl glycolate and butylphthalylbutyl glycolate; Glycolic acid esters of
And polyester of polyethylene glycol and aliphatic dibasic acid, such as polyester of triethylene glycol and adipic acid, polyester of diethylene glycol and succinic acid, etc. can be mentioned.

In order to improve the dispersibility of the stimulable phosphor layer phosphor particles in the stimulable phosphor layer coating solution, stearic acid, phthalic acid, caproic acid, lipophilic surfactants, etc. May be mixed. If necessary, a plasticizer for the binder may be added. Examples of the plasticizer include phthalic acid esters such as diethyl phthalate and dibutyl phthalate; diisodecyl succinate and aliphatic dibasic acid esters such as dioctyl adipate; ethyl phthalyl ethyl glycolate; butyl phthalyl butyl glycolate And the like.

Next, the coating solution prepared as described above is uniformly applied to the surface of the undercoat layer to form a coating film of the coating solution. This coating operation can be performed by using ordinary coating means, for example, a doctor blade, a roll coater, a knife coater, or the like.

Next, the formed coating film is dried by gradually heating to complete the formation of the stimulable phosphor layer on the undercoat layer. The thickness of the stimulable phosphor layer depends on the characteristics of the target radiation image conversion panel, the type of the stimulable phosphor, the mixing ratio of the binder and the phosphor, and the like.
μm to 1 mm. However, this layer thickness is 50 to 5
It is preferably set to 00 μm.

The preparation of the coating solution for the stimulable phosphor layer is carried out using a dispersing device such as a ball mill, a sand mill, an attritor, a three-roll mill, a high-speed impeller disperser, a Kady mill, and an ultrasonic disperser. The prepared coating solution is coated on a support using a coating solution such as a doctor blade, a roll coater, or a knife coater, and dried to form a stimulable phosphor layer. The stimulable phosphor layer and the support may be bonded to each other after the coating solution is applied on the protective layer and dried.

The thickness of the stimulable phosphor layer of the radiation image conversion panel of the present invention depends on the characteristics of the intended radiation image conversion panel, the type of stimulable phosphor, and the difference between the binder and the stimulable phosphor. Although it depends on the mixing ratio and the like, it is preferably selected from the range of 10 μm to 1000 μm, more preferably from the range of 10 μm to 500 μm.

[0081]

The present invention will now be illustrated by way of examples.

Example 1 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, 2500 ml of an ethanol solution (0.5 N) in which BaBr ₂ was dissolved and an ethanol solution of EuBr ₃ (0.03 N) ) 125 ml were placed in the reactor. The reaction mother liquor in the reactor was kept at 60 ° C. while stirring.
Ammonium fluoride ethanol solution (1.1N) 250m
1 was injected into the reaction mother liquor while controlling the flow rate using a high-precision cylinder pump to produce a precipitate. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluorobromide crystals. In order to prevent changes in particle shape due to sintering during firing, and changes in particle size distribution due to fusion between particles,
1% by weight of ultrafine alumina powder was added to the above crystals, and the mixture was sufficiently stirred with a mixer to uniformly adhere the ultrafine alumina powder to the crystal surface. This was filled in a quartz boat and calcined at 850 ° C. for 2 hours in a mixed gas atmosphere of hydrogen and nitrogen using a tube furnace to obtain europium-activated barium fluorobromide phosphor particles. Next, particles having an average particle diameter of 7 μm were obtained by classifying the phosphor particles.

Next, an example of manufacturing a radiation image conversion panel will be described.

As the phosphor layer forming material, 427 g of the europium-activated barium fluorobromide phosphor obtained above, 15.8 g of polyurethane resin (Desmolac 4125, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and bisphenol A type epoxy resin 0 g of methyl ethyl ketone-toluene (1: 1)
Add to the mixed solvent, disperse by propeller mixer,
A coating solution having a viscosity of 25 to 30 PS was prepared. This coating solution was applied onto a polyethylene terephthalate film with an undercoat using a doctor blade, and then dried at 100 ° C. for 15 minutes to form phosphor layers having various thicknesses.

Next, as a protective film forming material, 70 g of a fluororesin: fluoroolefin-vinyl ether copolymer (Lumiflon LF100 manufactured by Asahi Glass Co., Ltd.), 25 g of a crosslinker: isocyanate (Desmodur Z4370 manufactured by Sumitomo Bayer Urethane Co., Ltd.), bisphenol A Type epoxy resin 5g, and silicone resin fine powder (KMP-590,
10 g of a particle size of 1-2 μm (Shin-Etsu Chemical Co., Ltd.) was added to a mixed solvent of toluene-isopropyl alcohol (1: 1) to prepare a coating solution. This coating solution is applied to the phosphor layer formed in advance as described above using a doctor blade, and then heat-treated at 120 ° C. for 30 minutes to be heat-cured and dried. A membrane was provided.
By the above method, radiation image conversion panels having stimulable phosphor layers of various thicknesses were obtained.

Example 2 2500 ml of an NH ₄ Br ethanol solution (4.5 N) and 125 ml of an EuBr ₃ ethanol solution (0.03 N) were placed in a reactor. The reaction mother liquor in the reactor was kept at 60 ° C. while stirring. 250 ml of an ammonium fluoride ammonium solution (1.1 N) and 2500 ml of an ethanol solution (0.5 N) in which BaBr ₂ is dissolved are injected into the reaction mother liquor while controlling the flow rate using a high-precision cylinder pump. Generated. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluorobromide crystals. A panel was prepared by the method described in Example 1 using the above crystal.

Example 3 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluoroiodide, 2500 ml of an ethanol solution (0.5N) in which BaI ₂ was dissolved was placed in a reactor. The reaction mother liquor in this reactor was kept at 65 ° C. while stirring.
Ammonium fluoride ethanol solution (1.1N) 250m
l and 125 ml of EuI ₃ ethanol solution (0.03N)
Was injected into the reaction mother liquor while controlling the flow rate using a high feed precision cylinder pump to produce a precipitate. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. A panel was prepared by the method described in Example 1 using the above crystal.

Example 4 2500 ml of NH ₄ I ethanol solution (4.5N), E
125 ml of a uI ₃ ethanol solution (0.2N) were placed in the reactor. While stirring the reaction mother liquor in this reactor, 65
Incubated at ° C. Ammonium fluoride ethanol solution (1.
250 ml of 1N) and 2500 ml of an ethanol solution (0.5N) in which BaBr ₂ was dissolved were injected into the reaction mother liquor while controlling the flow rate using a high feed precision cylinder pump to produce a precipitate. Keep warm and stir after injection
The sediment was aged continuously over time. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. A panel was prepared by the method described in Example 1 using the above crystal.

Example 5 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluoroiodide, 2500 ml of an ethanol solution (0.5N) in which BaI ₂ was dissolved was placed in a reactor. The reaction mother liquor in this reactor was kept at 65 ° C. while stirring.
Ammonium fluoride ethanol solution (1.1N) 250m
1 was injected into the reaction mother liquor while controlling the flow rate using a high feed precision cylinder pump to produce a precipitate. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. After mixing the above crystal and EuI ₃ , the mixture is filled in a quartz boat, and calcined at 850 ° C. for 2 hours in a mixed gas atmosphere of hydrogen and nitrogen using a tube furnace to produce europium-activated barium fluoroiodide phosphor particles. I got A panel was prepared by the method described in Example 1 using the above crystal.

Example 6 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluoroiodide, an aqueous solution of BaI ₂ (3.5N) 2 was used.
500 ml and EuBr ₃ aqueous solution (0.2 N) 125 ml
Was placed in the reactor. The reaction mother liquor in this reactor was kept at 83 ° C. while stirring. Ammonium fluoride aqueous solution (8
N) 250 ml was injected into the reaction mother liquor using a high feed precision cylinder pump to produce a precipitate. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. In order to prevent a change in particle shape due to sintering during firing and a change in particle size distribution due to inter-particle fusion, 1% by weight of ultrafine alumina powder is added to the above crystal, By sufficiently stirring with a mixer, ultrafine alumina powder was uniformly attached to the crystal surface. This was filled in a quartz boat and calcined at 850 ° C. for 2 hours in a hydrogen gas atmosphere using a tube furnace to obtain europium-activated barium fluoroiodide phosphor particles. Using the above crystal,
A panel was prepared by the method described in Example 1.

Comparative Example 1 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, 2500 ml of an ethanol solution (0.1 N) in which BaBr ₂ was dissolved and an ethanol solution of EuBr ₃ (0.006 N) ) 125 ml were placed in the reactor. The reaction mother liquor in the reactor was kept at 60 ° C. while stirring. Ammonium fluoride ethanol solution (0.2N) 25
0 ml was injected into the reaction mother liquor while controlling the flow rate using a high-precision cylinder pump to produce a precipitate.
After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluorobromide crystals. In order to prevent a change in particle shape due to sintering during firing and a change in particle size distribution due to fusion between particles, 1% by weight of ultrafine alumina powder is added to the above crystal.
The resulting mixture was sufficiently stirred with a mixer to uniformly adhere the ultrafine alumina powder to the crystal surface. This was filled in a quartz boat and calcined at 850 ° C. for 2 hours in a mixed gas atmosphere of hydrogen and nitrogen using a tube furnace to obtain europium-activated barium fluorobromide phosphor particles. A panel was prepared by the method described in Example 1 using the above crystal.

Comparative Example 2 2500 ml of NH ₄ Br ethanol solution (4.5N)
EuBr ₃ ethanol solution (0.006N) 125ml
Was placed in the reactor. The reaction mother liquor in the reactor was kept at 60 ° C. while stirring. 250 ml of ammonium fluoride ethanol solution (0.2 N) and 2500 ml of ethanol solution containing BaBr ₂ (0.1 N) were injected into the reaction mother liquor while controlling the flow rate using a high-precision cylinder pump, and the precipitate was removed. Generated. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluorobromide crystals. A panel was prepared by the method described in Example 1 using the above crystal.

Comparative Example 3 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluoroiodide, an NH ₄ I-tanol solution (4.5) was used.
N) 2500 ml, EuI ₃ ethanol solution (0.00
6N) was placed in the reactor. The reaction mother liquor in this reactor was kept at 65 ° C. while stirring. 250 ml of ammonium fluoride ethanol solution (0.2N) and 2500 ml of an ethanol solution (0.1N) in which BaI ₂ was dissolved were injected into the reaction mother liquor while controlling the flow rate using a high feed precision cylinder pump, and the precipitate was removed. Generated. After completion of the injection, the precipitate was matured by keeping the temperature and stirring for 2 hours. Next, the precipitate was separated by filtration, washed with methanol, and dried under vacuum to obtain europium-activated barium fluoroiodide crystals. A panel was prepared by the method described in Example 1 using the above crystal.

Comparative Example 4 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaBr ₂ , 2H ₂ O powder (33
3.2 g) and BaF ₂ powder (175.4 g) and EuI
6.7 g of the _three powders were sufficiently mixed in a mortar, and heated and melted at 1100 ° C. for 4 hours in a hydrogen gas atmosphere using a tube-type electric furnace to obtain europium-activated barium fluorobromide phosphor particles. The obtained phosphor is pulverized and classified to have an average particle size of 7 μm.
m of the phosphor were obtained. Using the above phosphor, a panel was prepared by the method described in Example 1.

Comparative Example 5 In order to synthesize a stimulable phosphor precursor of europium-activated barium fluorobromide, BaI ₂ , 2H ₂ O powder (42
7.2 g) and BaF ₂ powder (175.4 g) and EuI
6.7 g of the _three powders were sufficiently mixed in a mortar, and heated and melted at 1000 ° C. for 4 hours in a hydrogen gas atmosphere using a tube type electric furnace to obtain europium-activated barium fluorobromide phosphor particles. The obtained phosphor is pulverized and classified to have an average particle size of 7 μm.
m of the phosphor were obtained. Using the above phosphor, a panel was prepared by the method described in Example 1.

(Evaluation of radiation image conversion panel) Regarding the sensitivity, after irradiating the radiation image conversion panel with X-rays having a tube voltage of 80 KVp, the panel was irradiated with He-Ne laser light (633n).
m), excitation was performed, and stimulated emission emitted from the phosphor layer was received by a photodetector (a photomultiplier with a spectral sensitivity of S-5), and the intensity was measured. In the table below, the sensitivities are shown as relative values.

Regarding the sharpness, the radiation image conversion panel was irradiated with X-rays having a tube voltage of 80 KVp through a lead MTF chart, and then operated by a panel He-Ne laser beam to be excited to emit light emitted from the phosphor layer. The emitted light is received by the same light receiver as above and converted into an electric signal, which is converted from analog to digital and recorded on a magnetic tape. The magnetic tape is analyzed by a computer and the X-ray image recorded on the magnetic tape Was examined for its modulation transfer function (MTF). The table below shows the MTF value (%) at a spatial frequency of 2 cycles / cm 2.

Regarding the graininess, the radiation image conversion panel was irradiated with X-rays having a tube voltage of 80 KVp, and then the panel was irradiated with He.
Excited by operating with -Ne laser light, the stimulated emission emitted from the phosphor layer is received by the same receiver as above and converted into an electrical signal, which is recorded on a normal photographic film by a film scanner, The granularity of the obtained image was visually evaluated. In the following table, the graininess is the same as the graininess of an image obtained by conventional practical X-ray photography using an intensifying screen (Konica SRO-250) and an X-ray photographic film (Konica SR-G). Shown in comparison. ○ means graininess equivalent to an image obtained by X-ray photography using the intensifying screen and film, and ◎ means better graininess. In addition, the symbol △ means a slightly coarser graininess than an image obtained by radiography, and the symbol × means a significantly coarser graininess than that. The average particle size of the stimulable phosphor was measured from a scanning electron micrograph.

[0099]

[Table 1]

[0100]

According to the present invention, the image characteristics represented by the sensitivity are extremely excellent.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiro Maezawa 1 Sakuracho, Hino-shi, Tokyo Konica Corporation

Claims (9)

[Claims] 1. A general formula ^{_{(1) Ba 1-x M}} 2 xF 1-a X 1 + a: yM 1, zLn M 2: Mg, Ca, Sr, at least one alkaline earth selected from the group consisting of Zn and Cd Like metals M ¹ : At least one kind of alkali metal selected from the group consisting of Li, Na, K, Rb and Cs X: At least one kind of halogen selected from the group consisting of Cl, Br, F and I Ln: Ce, Pr, Sm , Eu, Gd, Tb, Tm, D
at least one rare earth element x, y and z selected from the group consisting of y, Ho, Nd, Er and Yb is 0 ≦ x ≦ 0.5, 0 ≦ y ≦
0.05,0 <z ≦ 0.2, -0.5 is ≦ a ≦ 0.5 phosphor represented by a liquid to use a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ is dissolved A rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor obtained by a phase method. 2. The stimulable phosphor of the rare earth-activated alkaline earth metal fluoride halide according to claim 1, wherein the solvent is a solvent other than water. 3. The stimulable phosphor of the rare earth-activated alkaline earth metal fluoride halide type according to claim 2, wherein the solvent is an alcohol type. 4. A rare earth activated alkaline earth metal fluoride comprising the following steps for producing the rare earth activated alkaline earth metal fluorinated halide stimulable phosphor according to claim 1, 2 or 3. A method for producing a halide halide stimulable phosphor. Ba
X ₂ and a halide of Ln, and further, when x in formula (1) is not 0, further contains a halide of M ² , and when y is not 0, further contains a halide of M ^1. , after which they are dissolved in a solvent, preparing a solution BaX ₂ of more than 30% of the solubility of the solvent to BaX ₂ is dissolved; while maintaining the above solution at a temperature of above 50 ° C., this inorganic fluoride Adding a solution of (ammonium fluoride or an alkali metal fluoride) to obtain a precipitate of a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor precursor crystal; Separating the product from the solution; and firing the separated precursor crystal precipitate while avoiding sintering. 5. A rare earth activated alkaline earth metal fluoride comprising the following steps for producing the rare earth activated alkaline earth metal fluorinated halide stimulable phosphor according to claim 1, 2 or 3. A method for producing a halide halide stimulable phosphor. When the mother liquor contains an ammonium halide and a halide of Ln, and x in the general formula (1) is not 0,
Preparing an ammonium halide solution comprising a halide of M ² and, if y is not 0, further a halide of M ¹ , after they are dissolved in a solvent; And 30% of the solubility of the solvent in BaX ₂ with a solution of inorganic fluoride (ammonium fluoride or alkali metal fluoride).
A step of continuously or intermittently adding the solution in which BaX ₂ is dissolved to obtain a precipitate of a rare earth activated alkaline earth metal fluorinated halide-based stimulable phosphor precursor crystal; Separating the crystalline precipitate from the solution; and calcining the separated precursor crystalline precipitate while avoiding sintering. 6. A rare earth activated alkaline earth metal fluoride comprising the following steps for producing the rare earth activated alkaline earth metal fluorinated halide stimulable phosphor according to claim 1, 2 or 3. A method for producing a halide halide stimulable phosphor. When the mother liquor contains BaX ₂ and x in the general formula (1) is not 0, it further contains a halide of M ² , and when y is not 0, it further contains a halide of M ^1. After dissolution, 30% of the solubility of the solvent in BaX ₂
A step of preparing a solution in which BaX ₂ is dissolved; a solution of an inorganic fluoride (a fluoride of ammonium or an alkali metal) and a halide of Ln while maintaining the solution at a temperature of 50 ° C. or higher. Obtaining a precipitate of a rare earth-activated alkaline earth metal fluorohalide-based stimulable phosphor precursor crystal by adding a solution of the above; a step of separating the precursor crystal precipitate from the solution; and Baking the obtained precursor crystal precipitate while avoiding sintering. 7. A rare earth activated alkaline earth metal fluoride comprising the following steps for producing the rare earth activated alkaline earth metal fluoride halide stimulable phosphor according to claim 1, 2 or 3. A method for producing a halide halide stimulable phosphor. When the mother liquor contains BaX ₂ and x in the general formula (1) is not 0, it further contains a halide of M ² , and when y is not 0, it further contains a halide of M ^1. After dissolution, preparing an ammonium halide solution; while maintaining the above solution at a temperature of 50 ° C. or higher,
A solution of inorganic fluoride (ammonium fluoride or alkali metal fluoride), a solution of BaX _{2 having} a solubility of 30% or more of BaX ₂ in the solvent, and a solution of a halide of Ln were mixed with fluorine, Ba and Ln. Obtaining a precipitate of rare earth-activated alkaline earth metal fluorinated halide-based stimulable phosphor precursor crystals by adding continuously or intermittently while maintaining the ratio of Separating the product from the solution; and firing the separated precursor crystal precipitate while avoiding sintering. 8. The method for producing a rare earth-activated alkaline earth metal fluorinated halide stimulable phosphor according to claim 5 or 7, wherein the alkaline earth metal fluorinated halide stimulable fluorescent light is used. No Ln halide was added before the precursor crystal precipitate was formed, and Ln was not added after the precursor crystal precipitate was formed.
A method for producing a rare earth activated alkaline earth metal fluorohalide-based stimulable phosphor, characterized by adding a halide of 9. A radiation image conversion panel having a phosphor layer containing a stimulable phosphor, wherein the rare earth activated alkaline earth metal fluorinated halide stimulant according to claim 1, 2 or 3. A radiation image conversion panel comprising a luminescent phosphor.