JPH07126617A - Cerium-activated barium fluorohalide-based fluorescent material and radiological image conversion panel - Google Patents

Abstract

PURPOSE:To obtain a new cerium-activated barium fluorohalide-based fluorescent material improved in one or more properties of after image erasing properties, afterglow properties and accelerated phosphorescence intensity and a radiological image conversion panel in which the fluorescent material is utilized. CONSTITUTION:A cerium-activated barium fluorohalide-based fluorescent material and a radiological image conversion panel having a fluorescent material layer containing this accelerated phosphorescent material are provided. This cerium-activated barium fluorohalide-based fluorescent material is produced by adding 0.001 to 1.0mol% one or more kinds of metals selected from a group of Cu, Sn, Sb, Tl, Pb, Bi, Pr, Sm, Gd and Lu to a cerium-activated barium fluorohalide represented by the formula BAFX:bCe<3+> [provided that X is one or more kinds of halogens selected from Cl, Br and I. (b) is a number within a range of 10<-5=b<=10<-2>].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel cerium-activated barium fluorohalide-based stimulable phosphor and a radiation image conversion panel having a stimulable phosphor layer containing the stimulable phosphor. It is about.

[0002]

2. Description of the Related Art As a method replacing the conventional radiographic method, for example, a radiation image conversion method using a stimulable phosphor as described in JP-A-55-12145 is known. This method uses a radiation image conversion panel (stimulable phosphor sheet) containing a stimulable phosphor, and the radiation transmitted through the subject or emitted from the subject is stimulated by the stimulable fluorescence of the panel. The radiation energy accumulated in the stimulable phosphor is absorbed by the body and then the stimulable phosphor is excited in a time series with electromagnetic waves (excitation light) such as visible light and infrared rays. It emits fluorescent light (stimulated luminescence), photoelectrically reads this fluorescent light to obtain an electric signal, and then reproduces a radiation image of a subject or a subject as a visible image based on the obtained electric signal. . The panel that has finished reading is prepared for the next shooting after the remaining image is erased. That is, the radiation image conversion panel can be repeatedly used.

According to the above-mentioned radiographic image conversion method, compared with the conventional radiographic method using a combination of a radiographic film and an intensifying screen, the radiographic image having much information amount with much smaller exposure dose. There is an advantage that can be obtained. Further, in the conventional radiographic method, the radiographic film is consumed for each photographing, whereas in the radiographic image conversion method, the radiographic image conversion panel is repeatedly used. It is advantageous.

The stimulable phosphor is a phosphor which exhibits stimulated emission when irradiated with excitation light after being irradiated with radiation. However, in practice, the excitation light having a wavelength in the range of 400 to 900 nm causes emission of 300 to 300 nm. Phosphors that exhibit stimulated emission in the wavelength range of 500 nm are commonly used. An example of the stimulable phosphor that has been conventionally used in a radiation image conversion panel is a divalent europium-activated alkaline earth metal halide phosphor. The radiation image conversion panel used in the radiation image conversion method has, as a basic structure, a support and a stimulable phosphor layer provided on the surface of the support. However, when the phosphor layer is self-supporting, a support is not always necessary. The stimulable phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. However, it is known that the stimulable phosphor layer is composed of only aggregates of the stimulable phosphor without containing a binder formed by a vapor deposition method or a sintering method. Further, a radiation image conversion panel having a stimulable phosphor layer in which a polymer substance is impregnated in a gap between aggregates of the stimulable phosphor is also known. In any of these phosphor layers,
Since the stimulable phosphor has a property of exhibiting stimulated emission when it is irradiated with excitation light after absorbing radiation such as X-ray, the radiation transmitted through the subject or emitted from the subject is The radiation image is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and the 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 this stimulated emission light and converting it into an electric signal. It becomes 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 a vapor deposition film of an inorganic substance, and the phosphor layer Protects against chemical alteration or physical shock.

A large number of phosphors have been found so far in various applications. However, only a few kinds of phosphors having the above-described stimulability have been confirmed. Therefore, it is still important to search for a phosphor showing a stimulable level that can be practically used.

Conventionally, when irradiated with radiation such as X-rays, electron beams, or ultraviolet rays and then excited by electromagnetic waves (excitation light) in the visible or infrared region, light emission (stimulated emission) is shown in the near ultraviolet or blue region. As a stimulable phosphor, a cerium-activated barium fluorofluoride phosphor (BaFX: Ce ³⁺ ; where X is a halogen other than fluorine) is known (JP-A-55-12145, JP-A-55-12145). 55-84389
No. Therefore, this phosphor can be used as a stimulable phosphor for a radiation image conversion panel used in a radiation image conversion method. The cerium-activated barium fluorohalide phosphor has a faster response speed than the europium-activated barium fluorohalide phosphor, and therefore the cerium-activated barium fluorohalide phosphor is used in the radiation image conversion method. Then, there is an advantage that the reading of the image information is fast.

[0008] West German Patent No. 3834414 discloses
Cerium activated barium fluorobromide phosphor (BaFBr: C
It is described that sodium fluoride (NaF) or sodium hexafluorosilicate (Na ₂ SiF ₆ ) may be added in the production of e ³⁺ ), but the compound is a phosphor stimulated emission. There is no description of how it affects the brightness.

[0009]

As described above, the cerium-activated barium fluorohalide phosphor (BaFX: C) is used.
e ³⁺ ) is already known as a stimulable phosphor for a radiation image conversion panel in which the reading speed of image information is improved.
However, even in the above radiation image conversion method, X
It is desirable that the sensitivity is as high as possible in order to reduce the exposure dose due to radiation such as rays, and the stimulable phosphor to be used is required to have a high stimulated emission luminance as much as possible. In addition, in the conventional cerium-activated barium fluorohalide phosphor, when the radiation energy accumulated in the stimulable phosphor is emitted as fluorescence (stimulated luminescence) by excitation light, afterglow occurs. Conspicuous (that is, poor afterglow characteristics) and rising of afterimage (a phenomenon in which a latent image appears on the panel subjected to the erasing operation after the radiation image is reproduced from the radiation image conversion panel after a lapse of time; evaluated as afterimage erasing characteristics) Easy to do. Such undesired afterglow characteristics reduce the sharpness of the obtained radiation image, and the rise of the afterimage deteriorates the image characteristics when the radiation image conversion panel is reused. Therefore, improvement in these points is also desired. Be done. Therefore, the present invention provides a novel stimulable phosphor satisfying such requirements. More specifically, it is an object of the present invention to provide a novel cerium-activated barium fluorohalide phosphor having improved afterimage erasing properties, afterglow properties, and stimulated emission intensity. It is a thing.

[0010]

Means for Solving the Problems BaFX: bCe ³⁺ (I) (wherein X is at least one halogen selected from the group consisting of Cl, Br and I, and b is 10
^-5 ≤ b ≤ 10 ^-2 ) 0.001 to cerium activated barium fluoride halide represented by
In an amount of 1.0 mol%, Cu, Sn, Sb, Tl, Pb,
Cerium-activated barium fluorohalide-based phosphor to which at least one metal selected from the group consisting of Bi, Pr, Sm, Gd and Lu is added, and radiation having a phosphor layer containing this stimulable phosphor Image conversion panel. Examples of the metal include Sn, Sb, Pb, Tl, Bi, P
r, Sm, Gd and Lu are preferred, and Bi,
Pr, Sm, Gd and Lu are preferred. Further, the amount of the metal added is preferably 0.001 to 0.5 mol% and more preferably 0.01 to 0.5 mol% with respect to the cerium-activated barium fluorohalide of the general formula (I). b
The value of is preferably 10 ⁻⁵ or more (1 × 10 ⁻⁵ ≦ b), and is preferably 10 ⁻² or less (b ≦ 1 × 10 ⁻² ).

In addition to the above cerium-activated barium fluorohalide phosphor, NaX ', CsX ", CaX'" ₂ , SrX "" ₂ ,
CaO and SrO, where X ′ is Br and / or I; and X ″, X ′ ″ and X ″ ″ are at least one halogen selected from the group consisting of F, Cl, Br and I. It is preferable that at least one kind is added. Particularly, it is preferable to add at least one of NaX ', CsX ", CaX'" ₂ and SrX "" ₂ . NaX ', Cs above
X ", CaX '" ₂ , SrX "" ₂ , CaO and SrO are 0.01 to 10
It is preferably added in an amount of mol%, preferably 0.1 to 10 mol%.

The cerium-activated barium fluorohalide-based phosphor obtained by adding a metal such as Cu to the cerium-activated barium fluorohalide represented by the composition formula (I) of the present invention is 1) barium halide, Cerium compounds, and the above metals (Cu, Sn, Sb, Tl, Pb, Bi,
Pr, Sm, Gd and Lu) halide, and optionally a mixture of phosphor raw materials comprising sodium halide, cesium halide, calcium halide, strontium halide, calcium oxide and / or strontium oxide And 2) a step of firing the phosphor raw material mixture in a weakly reducing or neutral atmosphere or in a trace oxygen introducing atmosphere at a temperature in the range of 400 to 1300 ° C. for 0.5 to 10 hours. It can be manufactured.

An example of the method for producing the cerium-activated barium fluorohalide-based phosphor of the present invention will be described in detail below.

First, as phosphor raw materials, 1) barium fluoride (BaF ₂ ), 2) barium chloride (BaCl ₂ ), barium bromide (Ba)
Br ₂ ) and at least one barium halide selected from the group consisting of barium iodide (BaI ₂ ) provided that BaFCl, instead of the raw materials of 1) and 2) above,
Barium halide such as BaFBr or BaFI may be used. 3) at least one compound selected from the group consisting of cerium compounds such as halides, oxides and nitrates, and further 4) copper chloride (CuCl), copper bromide (CuBr), copper iodide (CuI), tin chloride (SnCl ₂ ), tin bromide (SnBr
_2), iodide of tin (SnI _2), lead chloride (PbCl _2), lead bromide (PbBr _2), iodide of lead (PbI _2), thallium chloride (TlCl), thallium bromide (TlBr), iodide thallium (TlI), antimony chloride (SbCl ₃ ), antimony bromide (SbBr ₃ ), antimony iodide (SbI)
₃ ), bismuth chloride (BiCl ₃ ), bismuth bromide (B
iBr ₃ ), bismuth iodide (BiI ₃ ), praseodymium chloride (PrCl ₃ ), praseodymium bromide (PrBr)
₃ ), praseodymium iodide (PrI ₃ ), samarium chloride (SmCl ₃ ), samarium bromide (SmBr ₃ ), samarium iodide (SmI ₃ ), gadolinium chloride (GdCl)
₃ ), gadolinium bromide (GdBr ₃ ), gadolinium iodide (GdI ₃ ), lutetium chloride (LuCl ₃ ), lutetium bromide (LuBr ₃ ) and / or lutetium iodide (LuI ₃ ), and optionally, 5) Sodium bromide (NaBr), sodium iodide (N
aI), cesium fluoride (CsF), cesium chloride (Cs
Cl), cesium bromide (CsBr), cesium iodide (C
sI), calcium fluoride (CaF ₂ ), calcium chloride (CaCl ₂ ), calcium bromide (CaBr ₂ ), calcium iodide (CaI ₂ ), strontium fluoride (SrF)
₂ ), strontium chloride (SrCl ₂ ), strontium bromide (SrBr ₂ ), strontium iodide (SrI)
₂ ), calcium oxide (CaO), and / or strontium oxide (SrO) are prepared. In some cases, an ammonium halide (NH ₄ X ″; where X ″ is Cl, Br or I) or the like may be used as a flux.

In the production of the phosphor, first, the relative ratio of the barium fluoride of 1), the barium halide of 2) and the cerium compound of 3) is stoichiometrically in accordance with the composition formula (I). And measure the amount of the metal component such as copper chloride in 4) with respect to BaFX: bCe ³⁺ to 0.005.
It is weighed so as to be 1 to 1.0 mol%, and they are mixed to prepare a mixture of phosphor raw materials. Furthermore, above 5)
In the case of adding sodium bromide, etc., in the same manner, the components are added and mixed in an amount of 0.01 to 10 mol% with respect to BaFX: bCe ³⁺ .

The preparation of the phosphor raw material mixture is carried out by i) simply mixing the phosphor raw materials of 1) to 4) (or 1) to 5)), ii) the above 1), 2) and 4) (or 1). ), 2),
The phosphor raw materials of 4) and 5)) are first mixed, the mixture is heated at a temperature of 100 ° C. or higher for several hours, and then the heat-treated product is mixed with the phosphor raw material of 4) above, iii) the above 1), 2) and 4) (or 1), 2),
The phosphor raw materials of 4) and 5)) are first mixed in a suspension state, and the suspension is dried under reduced pressure (preferably at a temperature of 50 to 200 ° C.) under reduced pressure, vacuum drying, spray drying or the like. It may be carried out by any method such as drying, and then mixing the dried material with the phosphor raw material of the above 4).

As a modification of the method ii), a method may be used in which the phosphor raw materials 1) to 4) (or 1) to 5)) are mixed and the mixture is subjected to the heat treatment. . In addition, as a modification of the above method iii), the above 1) to
A method of mixing the phosphor raw materials of 4) (or 1) to 5)) in a suspension state and drying the suspension may be used. Alternatively, the phosphor material of 3) above may be added to and mixed with the mixture after the heat treatment or after drying. If the firing is performed twice or more, the phosphor raw material of 3) above may be added after the primary firing. Good.

In any of the above methods i), ii), and iii), various mixers, V-type blenders, ball mills, rod mills, and other ordinary mixers are used for mixing.

Next, the phosphor raw material mixture prepared as described above is filled in a heat-resistant container such as a quartz boat, an alumina crucible, and a quartz crucible, and placed in the core of an electric furnace for firing. The firing temperature is suitably in the range of 400 to 1300 ° C, preferably 500 to 1100 ° C.
The firing time varies depending on the filling amount of the phosphor raw material mixture, the firing temperature, the temperature at which the material is taken out of the furnace, and the like, but 0.5 to 10 hours is generally suitable. As the firing atmosphere,
A neutral atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere, a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide atmosphere containing carbon monoxide, or a trace oxygen introduction atmosphere is used. .

After the phosphor raw material mixture is once fired as described above, the fired product is taken out of the electric furnace and allowed to cool, and if necessary, a mortar, ball mill, tube mill,
It is also possible to pulverize into a fine powder using an ordinary pulverizer such as a centrifugal mill, and then put the pulverized product in an electric furnace for re-baking (secondary calcination). The firing temperature for re-firing is 400
〜1300 ℃ is suitable, and the firing time is 0.5〜.
10 hours is appropriate, and the firing atmosphere may be the above-mentioned weak reducing atmosphere or neutral atmosphere, or the atmosphere into which a trace amount of oxygen has been introduced.

A powdery phosphor is obtained by the above firing. The obtained phosphor may be subjected to various general operations in the production of the phosphor such as washing, drying, and sieving, if necessary. Since the phosphor is easily decomposed by warm water, washing is performed with an organic solvent such as acetone, ethyl acetate, ethanol and the like.

According to the manufacturing method described above, the above 1)
To 4), BaFX: bCe ³⁺ (I) (wherein X is at least one halogen selected from the group consisting of Cl, Br and I, and b is 10).
^{-5≤b≤10 -2} ) 0.001 to 1.0 for cerium-activated barium fluorohalide represented by the formula
Cu, Sn, Sb, Tl, Pb, Bi,
A cerium-activated barium fluorohalide-based phosphor to which at least one metal selected from the group consisting of Pr, Sm, Gd and Lu is added is obtained; and 1) to 5) above.
In the case of using the above component, the above cerium-activated barium fluorofluoride phosphor, further NaX ', CsX ", CaX'" ₂ , SrX "" ₂ ,
CaO and SrO (wherein X is at least one halogen selected from the group consisting of Cl, Br and I; X ′
Is Br and / or I; X ″, X ′ ″ and X ″ ″ are at least one halogen selected from the group consisting of F, Cl, Br and I) and at least one of 0.0
A cerium-activated barium fluorohalide-based phosphor added in an amount of 1 to 10 mol% is obtained.

Next, a method for manufacturing the radiation image storage panel of the present invention will be described.

In the stimulable phosphor layer of the radiation image storage panel of the present invention, the above-mentioned metal such as Cu is added to the cerium-activated barium fluorohalide represented by the general formula (I) (if desired, further). A layer containing a cerium-activated barium fluorohalide-based phosphor (to which sodium halide or the like is added), which is usually composed of a stimulable phosphor and a binder containing and supporting it in a dispersed state. However, if necessary, a fluorescent substance in which a polymer substance is impregnated in the gap between the stimulable phosphor aggregates without a binder, or composed only of the stimulable phosphor aggregates. It may be a body layer or the like.

Next, the method for producing the radiation image storage panel of the present invention will be described by taking as an example the case where the phosphor layer is composed of a stimulable phosphor and a binder which contains and supports the stimulable phosphor in a dispersed state.

The phosphor layer can be formed on the support by the following known method. First, a stimulable phosphor and a binder are added to a solvent and mixed sufficiently to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in a binder solution. The mixing ratio of the binder and the stimulable phosphor in the coating solution varies depending on the characteristics of the intended radiation image conversion panel, the kind of the phosphor, etc., but generally the mixing ratio of the binder and the phosphor is 1 It is preferably selected in the range of 1 to 1: 100 (weight ratio), and particularly preferably in the range of 1: 8 to 1:40 (weight ratio). The coating solution containing the phosphor and the binder prepared as described above is then uniformly applied to the surface of the support to form a coating film. This coating operation can be performed by using an ordinary coating means such as a doctor blade, a roll coater or a knife coater.

The support can be arbitrarily selected from materials known as a support for conventional radiation image conversion panels. In a known radiation image conversion panel, a phosphor layer is provided in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality (sharpness, graininess) of the radiation image conversion panel. The surface of the side support is coated with a polymer substance such as gelatin to form an adhesion-imparting layer, or a light-reflecting layer made of a light-reflecting substance such as titanium dioxide, or a light-absorbing substance made of a light absorbing substance such as carbon black. It is known to provide an absorbing layer and the like. The support used in the present invention can also be provided with these various layers, and their configuration can be arbitrarily selected according to the desired purpose and application of the radiation image conversion panel. Further, JP-A-58-20020
As described in Japanese Unexamined Patent Publication (Kokai) No. 0, the surface of the support on the side of the phosphor layer (adhesion-imparting layer, light reflection When a layer, a light absorption layer, or the like is provided, it means the surface thereof), and fine irregularities may be formed.

After forming the coating film on the support as described above, the coating film is dried to complete the formation of the stimulable phosphor layer on the support. The layer thickness of the phosphor layer varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, the mixing ratio of the binder and the phosphor, etc., but is usually 20 μm to 1 μm.
mm. However, this layer thickness is preferably 50 to 500 μm. The stimulable phosphor layer does not necessarily have to be formed by directly applying the coating liquid on the support as described above. For example, a sheet such as a glass plate, a metal plate or a plastic sheet may be separately formed. After forming the phosphor layer by applying the coating solution onto the substrate and drying it, the phosphor layer is pressed onto the support or an adhesive is used to bond the support and the phosphor layer. Good.

As mentioned above, a protective film is usually provided on the 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 polymethylmethacrylate in a suitable solvent onto the phosphor layer, or polyethylene. An organic polymer film such as terephthalate or a protective film forming sheet such as a transparent glass plate is separately formed and provided on the surface of the phosphor layer with an appropriate adhesive, or an inorganic compound is deposited by vapor deposition or the like. What was formed into a film on the layer is used. Further, it may be a protective film formed of a coating film of an organic solvent-soluble fluororesin and containing perfluoroolefin resin powder or silicone resin powder dispersed and contained therein.

For the purpose of improving the sharpness of the obtained image, at least one of the above layers constituting the radiation image storage panel of the present invention absorbs excitation light,
It may be colored with a coloring agent that does not absorb stimulated emission light, or an independent coloring intermediate layer may be provided (see Japanese Patent Publication No. 54-23400).

By the above method, the metal such as Cu is added to the cerium-activated barium fluorohalide represented by the general formula (I) on the support (additional sodium halide is added if desired). It is possible to produce a radiation image conversion panel of the present invention, which is provided with a phosphor layer comprising a cerium-activated barium fluorohalide-based stimulable phosphor and a binder containing and supporting the cerium-activated barium fluoride halide in a dispersed state. it can.

[0032]

EXAMPLES Example 1 Barium Fluorobromide (BaFBr) 0.85
Molar (200.80 g), barium fluoroiodide (BaF)
I) 0.15 mol (42.48 g), cerium bromide (C
After thoroughly mixing 3 × 10 ⁻³ mol (1.139 g) of eBr ₃ ) with a ball mill, add copper chloride (CuCl) to the mixture.
0.297 g was added and mixed evenly. This mixture was filled in a quartz boat, placed in a tube type electric furnace, and fired at a temperature of 930 ° C. for 2 hours in a nitrogen atmosphere. After firing, the quartz boat was taken out of the electric furnace and cooled to room temperature in a nitrogen atmosphere. The fired product obtained was crushed and then sieved. Thus BaFBr _0.85 Cu is added 0.3 mole percent I _0.15: was obtained 0.003 Ce ³⁺ in the composition formula cerium activated fluoride bromide barium iodide phosphor.

[Examples 2 to 12] The method of Example 1 except that 0.297 g of copper chloride (CuCl) was used in the same manner as in Example 1 except that the halides shown in Table 1 were used in the addition amounts shown in Table 1. By performing the same operation as
n (Example 2), Pb (Example 3), Pb (Example 4), Tl (Example 5), Tl (Example 6), Sb (Example 7), Bi (Example 8), Pr (Example 9), Sm
Example 10 BaFBr with 0.3 mol% Gd (Example 11) and Lu (Example 12) added
A cerium-activated barium fluorobromide iodide-based phosphor having a composition formula of _0.85 I _0.15 : 0.003 Ce ³⁺ was obtained.

Comparative Example 1 BaFBr was prepared in the same manner as in Example 1 except that copper chloride (CuCl) was not used.
A cerium-activated barium fluorobromide iodide-based phosphor represented by the composition formula of _0.85 I _0.15 : 0.003 Ce ³⁺ was obtained.

[Example 13] In Example 2, 0.1 mol% (0.103) of sodium bromide (NaBr) was further added.
The same operation as in the method of Example 2 was carried out except that g) was used.
FBr _0.85 I _0.15 · 0.001 NaBr: to obtain a cerium-activated fluoride bromide barium iodide phosphor represented by a composition formula of 0.003Ce ^3+.

[Example 14] In Example 2, 0.1 mol% (0.213 g) of cesium bromide (CsBr) was further added.
By performing the same operation as in the method of Example 2 except that was used, BaFB containing 0.3 mol% of Sn was added.
A cerium-activated barium fluorobromide iodide-based phosphor represented by the composition formula of r _0.85 I _0.15 · 0.001 CsBr: 0.003 Ce ³⁺ was obtained.

[Example 15] In Example 2, 0.1 mol% (0.078) of calcium fluoride (CaF ₂ ) was further added.
The same operation as in the method of Example 2 was carried out except that g) was used.
_{FBr 0.85 I 0.15 · 0.001 CaF 2} : obtain a 0.003Ce ³⁺ cerium represented by the composition formula activated fluoride bromide barium iodide phosphor.

[Example 16] In Example 2, 0.1 mol% (0.1%) of strontium fluoride (SrF ₂ ) was further added.
Except for using 26 g) by carrying out the same operation as the method of Example 2, Sn 0.3 mol% the added _{BaFBr 0.85 I 0.15 · 0.001 SrF 2} : 0.003 Ce 3+
A cerium-activated barium fluorobromide iodide-based phosphor represented by the following composition formula was obtained.

[Evaluation of Phosphor] (1) PSL Sensitivity (Stimulated Luminescence Luminance) After each phosphor was irradiated with 100 mR of 80 KVp X-ray, 12 J of He-Ne laser light (633 nm) was irradiated.
/ M ² irradiated by exciting, by the stimulated light emitted from the phosphor is received by a photomultiplier tube through a filter (B-410), were measured photostimulated luminescence luminance of the phosphor. (2) Afterimage erasing property After measuring the above-mentioned stimulated emission luminance, each phosphor was erased with a Na lamp for 2000000 lux.sec. The stimulated emission luminance of the phosphor was measured in the same manner as. The afterimage erasing characteristic is
It is shown as a relative value to the initial sensitivity. (3) PSL afterglow (stimulated afterglow) After irradiating 100 mR of 80 KVp X-rays to each of the above phosphors, a semiconductor laser beam (680 nm) of 12 J / m
² Excitation upon irradiation, stimulated emission luminance immediately before the laser irradiation was stopped and 50 msec. After the laser irradiation was stopped. The subsequent stimulated emission luminance was measured by receiving the stimulated emission light emitted from the phosphor through a filter (B-410) with a photomultiplier tube. Then, the PSL afterglow was obtained from the following formula, and the value was expressed in logarithm.

In the evaluation of the phosphors by the above-mentioned measurement, A is superior when compared with the known cerium-activated barium halide phosphor (Comparative Example 1), B is comparable, and inferior. Is designated as C. The obtained results are shown in Tables 1 and 2.

[0041]

[Table 1]

[0042]

[Table 2]

[Experimental Results] As is clear from the results shown in Table 1, Cu, Sn, Sb, Tl, Pb, Bi, P
The cerium-activated barium fluorobromide iodide-based phosphor of the present invention containing a small amount of r, Sm, Gd or Lu (Examples 1 to 1)
2) showed excellent characteristics in at least one of afterimage erasing characteristics and afterglow characteristics as compared with the known cerium-activated barium halide-based phosphor (Comparative Example 1) to which these were not added. Furthermore, the cerium-activated barium fluorobromide iodide-based phosphors of the present invention (Examples 8 to 12) in which Bi, Pr, Sm, Gd or Lu are added in a small amount are known cerium-activated substances in which these are not added. As compared with the barium halide-based phosphor (Comparative Example 1), it showed stimulated luminescence with higher brightness, and showed the same or equal or higher afterimage erasing characteristics and afterglow characteristics. Further, the phosphors into which NaBr or the like was further introduced (Examples 13 to 16) also showed high intensity stimulated emission and showed good afterimage erasing characteristics and afterglow characteristics.

[Embodiment 17] Next, an example of manufacturing the radiation image storage panel of the present invention will be described. BaF containing 0.3 mol% of Cu obtained in Example 1 as a phosphor layer forming material
Br _0.85 I _0.15 : 0.003 Ce ³⁺ cerium-activated barium fluorobromide-based phosphor 356 g, polyurethane resin (Sumitomo Bayer Urethane Co., Ltd. Desmolac 4125) 1
5.8 g and bisphenol A type epoxy resin 2.0 g were added to a methyl ethyl ketone-toluene (1: 1) mixed solvent, dispersed by a propeller mixer, and the viscosity was 25 to 3
A coating solution of 0PS was prepared. This coating solution was applied onto an undercoated polyethylene terephthalate film using a doctor blade and then dried at 100 ° C. for 15 minutes,
A phosphor layer was formed.

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

[Examples 18 to 32] The same operation as in Example 17 was carried out except that the cerium-activated barium fluorobromide iodide type phosphors obtained in Examples 2 to 16 were used as the phosphor. A radiation image conversion panel comprising a support, a stimulable phosphor layer and a protective layer, respectively, was thus obtained.

Claims (6)

[Claims] 1. Compositional formula (I): BaFX: bCe ³⁺ (I) (wherein X is at least one halogen selected from the group consisting of Cl, Br and I, and b is 10).
^-5 ≤ b ≤ 10 ^-2 ) 0.001 to cerium activated barium fluoride halide represented by
In an amount of 1.0 mol%, Cu, Sn, Sb, Tl, Pb,
A cerium-activated barium fluorohalide-based phosphor to which at least one metal selected from the group consisting of Bi, Pr, Sm, Gd and Lu is added. 2. Further, NaX ', CsX ", CaX'" ₂ , SrX "" ₂ ,
From CaO and SrO, where X'is Br and / or I, and X ", X '" and X "" are at least one halogen selected from the group consisting of F, Cl, Br and I. The cerium-activated barium fluorohalide-based phosphor according to claim 1, wherein at least one selected from the group consisting of 0.01 to 10 mol% is added. 3. NaX ', CsX ", CaX'" ₂ and SrX "" ₂
(However, X ′ is Br and / or I, and X ″, X ′ ″ and X ″ ″ are at least one halogen selected from the group consisting of F, Cl, Br and I.)
At least one selected from the group consisting of 0.01 to 1
The cerium-activated barium fluorohalide-based phosphor according to claim 1, which is added in an amount of 0 mol%. 4. A radiation image conversion panel having a phosphor layer containing a stimulable phosphor, wherein the stimulable phosphor has a composition formula (I): BaFX: bCe ³⁺ (I) (where X is At least one halogen selected from the group consisting of Cl, Br and I, and b is 10
^-5 ≤ b ≤ 10 ^-2 ) 0.001 to cerium activated barium fluoride halide represented by
In an amount of 1.0 mol%, Cu, Sn, Sb, Tl, Pb,
A radiation image conversion panel, which is a cerium-activated barium fluorohalide-based phosphor to which at least one metal selected from the group consisting of Bi, Pr, Sm, Gd, and Lu is added. 5. The cerium-activated barium fluorohalide-based phosphor further comprises NaX ', CsX ", CaX'" ₂ , SrX "" ₂ , and CaO.
And SrO (where X ′ is Br and / or I, and X ″, X ′ ″ and X ″ ″ are F, Cl, Br and I).
Is at least one halogen selected from the group consisting of), and at least one selected from the group consisting of 0.01
The radiation image storage panel according to claim 4, wherein the radiation image storage panel is added in an amount of -10 mol%. 6. The cerium-activated barium fluorohalide-based phosphor further comprises NaX ', CsX ", CaX'" ₂ and SrX "" ₂ (where X'is Br and / or I, and X ", X
"" And X "" are at least one halogen selected from the group consisting of F, Cl, Br and I) and 0.01 to 10 mol% of at least one selected from the group consisting of
The radiation image conversion panel according to claim 4, wherein the radiation image conversion panel is added in an amount of.