JPH06340873A - Alkali halide fluorescencer, radiation image conversion panel using the same, and radiation image conversion method using radiation image conversion panel - Google Patents

Abstract

PURPOSE:To provide an alkali halide fluorescencer which exhibits accelerated phosphorescence with high luminance and low afterglow. CONSTITUTION:An alkali halide fluorescencer is represented by the general compsn. formula: M<1>X.aM<2>X'2.bM<3>X''; cTl<+>, dPb<2+> (wherein M<1> means at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs; M<2> means at least one divalent metal selected from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu, and Ni; M<3> means at last one trivalent metal selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, En, etc.; each of X, X', and X'' means at least one halogen selected from the group consisting of F, Cl, Br, and I; 0<=a<=0.3; 0<=b<=0.3; 10<-6=c<=10<-2>; and 10<-6=d<=10-<2>).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thallium- and lead-activated alkali halide phosphor, a radiation image conversion panel using the phosphor and a radiation image reading method using the radiation image conversion panel.

[0002]

2. Description of the Related Art Conventionally, a so-called radiographic method using a silver salt has been used to obtain a radiographic image, but a method for imaging a radiographic image without using the silver salt has been developed. That is, the radiation that has passed through the subject is absorbed by the fluorescent substance, and then this fluorescent substance is excited with a certain energy to cause the radiation energy accumulated by this fluorescent substance to be emitted as fluorescent light, and this fluorescent light is detected. A method of imaging is disclosed. As a specific method, a radiation image conversion method using a panel having a stimulable phosphor layer formed on a support and using one or both of visible rays and infrared rays as excitation energy is known (US Pat. No. 3,859, 52
No. 7).

A radiation image conversion method using a stimulable phosphor is described in, for example, JP-A-59-75200.
Radiation image conversion method using FX: Eu ²⁺ system (X: Cl, Br, I) phosphor, radiation image conversion method using alkali halide phosphor described in JP-A-61-72087, etc. It has been known. Further, in JP-A-61-73786, 61-73787, Tl ⁺ and Ce ³⁺ , Sm ³⁺ , Eu ³⁺ as co-activators,
^{Y 3+, Ag +, Mg 2+} , Pb 2+, alkali halide phosphor containing a metal of In ³⁺ is known.

[0004]

When a radiation image conversion panel made of a stimulable phosphor is used for radiography such as X-ray photography for medical diagnosis, the exposure dose to the human body is reduced. Therefore, it is desired that the sensitivity of the radiation image conversion panel, that is, the stimulated emission brightness of the stimulable phosphor is high. In addition, this accumulated image is usually accumulated by using laser light as excitation light and scanning the radiation image conversion panel with this laser light to excite the stimulable phosphor in the radiation image conversion panel in time series. The emitted radiation energy is emitted as fluorescence, and this fluorescence is detected by a photodetector. Therefore, the fluorescence that is continuously emitted after the stimulable phosphor used in the radiation image conversion panel stops excitation by the excitation light, that is, the afterglow (stimulation afterglow) is the S / N ratio of the obtained image. This causes deterioration and deteriorates the image quality. Therefore, it is desirable that the photostimulable phosphor used for the radiation image conversion panel has less photostimulable afterglow, that is, does not emit light in a shorter time after the excitation by the excitation light is stopped.

However, the above-mentioned stimulable phosphor is not sufficiently satisfactory in terms of stimulated emission brightness and stimulated afterglow, and improvements thereof are desired. In addition, JP-A-61-737
In the alkali halide phosphors described in Nos. 86 and 61-73787, the content of the coactivator has a wide range of 0 or more and less than 0.2, and may not be contained.

In view of the above points, an object of the present invention is to provide an alkali halide phosphor having higher stimulated emission luminance and less stimulated afterglow. Another object of the present invention is to provide a radiation image conversion panel that provides a radiation image with higher stimulated emission luminance and less stimulated afterglow. Another object of the present invention is to provide a radiation image conversion method that provides a radiation image with higher stimulated emission luminance and less stimulated afterglow.

[0007]

According to the above-mentioned object of the present invention, various examinations have been made on phosphors which exhibit high-intensity stimulated emission and have little stimulated afterglow. As a result, they are represented by the following general formula (1). The object of the present invention can be achieved by an alkali halide phosphor, a radiation image conversion panel using the phosphor, and a radiation image conversion method using the radiation image conversion panel.

General formula (1) M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : cTl ⁺ , dPb ²⁺ (wherein M ¹ is at least one selected from Li, Na, K, Rb and Cs) Is an alkali metal and M ² is Be, M
At least one divalent metal selected from g, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
at least one trivalent metal selected from o, Er, Tm, Yb, Lu, Al, Ga and In, X, X'and X "are at least one halogen selected from F, Cl, Br and I. there. Furthermore, a, b, c and d are each 0 ≦ a ≦ 0.3,0 ≦ b ≦ 0.3,10 -6 ≦ c ≦ 10 -2, 10 -6
It is a numerical value in the range of ≤d≤10 ^-2 . That is, after irradiating the alkali halide phosphor of the present invention with radiation such as X-rays, ultraviolet rays and electron beams, the phosphor is irradiated with one or both of visible light and infrared rays to stimulate excitation, which is conventionally known. As compared with the case where the same operation is performed using the known alkali halide phosphor, the photoluminescence is clearly stronger and the photoluminescence afterglow is reduced.

Further, the alkali halide phosphor of the present invention can be used as a sensitizer, a phosphor for an X-ray image intensifier, etc. in addition to the radiation image conversion panel.

In the radiation image conversion panel of the present invention, basically, a support and at least one of at least one phosphor provided on one side or both sides of the support are at least one of the alkali halide phosphors of the general formula (1). It consists of layers.

Further, the radiation image conversion method of the present invention is carried out in the form of using a radiation image conversion panel containing the alkali halide phosphor of the general formula (1).

The structure of the present invention will be described in detail below along with its operation.

FIG. 1 shows one of the phosphors according to the present invention.
RbI: 10 ^-4 Tl ⁺ , dPb ²⁺ phosphor, tube voltage 80KV _P , tube current 10mA
After irradiating X-rays for 0.1 seconds, this is irradiated with a semiconductor laser beam (780
FIG. 3 is a diagram showing the relationship between the Pb ²⁺ content and the emission intensity due to photostimulation radiated from the phosphor layer after being excited at 10 nmW). In FIG. 1, the vertical axis represents d = 0, that is, the relative intensity with the emission intensity of RbI: 10 ⁻⁴ Tl ⁺ phosphor containing no Pb ²⁺ as 1 as the emission intensity. As is clear from FIG.
The emission intensity due to photostimulation is remarkably enhanced by the inclusion of Pb ²⁺ , and a sufficient effect can be obtained when the content d is in the range of 10 ⁻⁶ ≦ d ≦ 10 ⁻² , and particularly 10 ⁻⁵ ≦ d ≦ 10 ⁻ The effect is remarkable in the range of ³ .

The alkali halide phosphor represented by the above general formula (1) of the present invention is produced, for example, by the production method described below.

First, in the case of the firing method, as the phosphor raw material: 1) LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, K
F, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl,
CsBr, 1 kind or 2 or more of _{CsI, 2) BeF 2, BeCl} 2, BeBr 2, BeI 2, MgF 2, MgCl 2, MgBr 2,
_{MgI 2, CaF 2, CaCl 2} , CaBr 2, CaI 2, SrF 2, SrCl 2, SrB
r ₂ , SrI ₂ , BaF ₂ , BaCl ₂ , BaBr ₂ , BI ₂ , ZnF ₂ , ZnCl ₂ , Zn
_{Br 2, ZnI 2, CdF 2} , CdCl 2, CdBr 2, CdI 2, CuF 2, CuCl 2,
_{CuBr 2, CuI 2, NiF 2} , NiCl 2, NiBr 2, NiI 2 2 divalent metal one or two or more of _{such, 3) ScF 3, ScCl 3} , ScBr 3, ScI 3, YF 3, YCl 3 , YBr ₃ , Y
_{I 3, LaF 3, LaCl 3} , LaBr 3, LaI 3, CeF 3, CeCl 3, CeBr 3,
CeI ₃ , PrF ₃ , PrCl ₃ , PrBr ₃ , PrI ₃ , NdF ₃ , NdCl ₃ , NdB
r ₃ , NdI ₃ , PmF ₃ , PmCl ₃ , PmBr ₃ , PmI ₃ , SmF ₃ , SmCl ₃ , S
_{mBr 3, SmI 3, EuF 3} , EuCl 3, EuBr 3, EuI 3, GdF 3, GdC
l ₃ , GdBr ₃ , GdI ₃ , TbF ₃ , TbCl ₃ , TbBr ₃ , TbI ₃ , DyF ₃ , D
_{yCl 3, DyBr 3, DyI 3} , HoF 3, HoCl 3, HoBr 3, HoI 3, Er
_{F 3, ErCl 3, ErBr 3} , ErI 3, TmF 3, TmCl 3, TmBr 3, TmI 3,
_{YbF 3, YbCl 3, YbBr 3} , YbI 3, LuF 3, LuCl 3, LuBr 3, Lu
I ₃ , AlF ₃ , AlCl ₃ , AlBr ₃ , AlI ₃ , GaF ₃ , GaCl ₃ , GaBr ₃ ,
One of trivalent metals such as GaI ₃ , InF ₃ , InCl ₃ , InBr ₃ , InI ₃
Or 2 or more, 4) TlF, TlCl, TlBr, TlI, Tl ₂ O, Tl ₂ O ₃ , TlOH, Tl ₂ CO
₃ , one or more of thallium compounds such as TlNO ₃ , 5) PbF ₂ , PbCl ₂ , PbBr ₂ , PbI ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb
₃ O ₄ , PbSO ₄ , Pb (NO ₃ ) ₂ , PbCO ₃ , Pb (C ₁₇ H ₃₃ COO) ₂ , (CH ₃ C
One or more lead compounds such as (OO) ₂ Pb and (CH ₃ COO) ₂ Pb / 3H ₂ O are used.

The above raw materials are weighed so as to have the mixed composition represented by the general formula (1), and sufficiently mixed using a ball mill, a mixer mill, a mortar or the like.

In the phosphor of the present invention, M ¹ in the above general formula (1) is taken into consideration in terms of stimulated emission luminance and stimulated afterimage.
Is preferably at least one alkali metal selected from K, Rb and Cs. As X, at least one halogen selected from Br and I is preferable. M ²
It is preferable to use at least one divalent metal selected from Be, Mg, Ca, Sr and Ba. M ³ is Y,
At least one trivalent metal selected from Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In is preferable. M ³
B value representing the content of X ″ ₃ and d representing the content of Pb ²⁺
The values are preferably selected from the range of ^{0≤b≤10 -2} and 10 ^-5 ≤d≤10 ^-3 , respectively. Further, a low melting point as a Pb compound _{PbF 2, PbCl 2, PbBr 2} , PbI 2, Pb (NO 3) 2, Pb (C 17
H ₃₃ COO) ₂ , (CH ₃ COO) ₂ Pb, (CH ₃ COO) ₂ Pb · 3H ₂ O are preferable, and Pb (NO ₃ ) ₂ is particularly preferable.

Next, the obtained phosphor raw material mixture is filled in a heat-resistant container such as a quartz crucible or an alumina crucible and fired in an electric furnace. The firing temperature is suitably 400 to 1000 ° C, preferably 500 to 700 ° C. The firing time varies depending on the filling amount of the raw material mixture, the firing temperature, etc., but is generally 0.
It is suitable for 2 to 10 hours, preferably 1 to 4 hours.
The firing atmosphere is preferably a neutral atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere, or an oxidizing atmosphere containing oxygen gas. After firing once under the above firing conditions,
The fired product is taken out of the electric furnace and crushed, and then the fired product powder is charged again into the heat-resistant container and placed in the electric furnace, and refired under the same firing conditions as described above. The brightness can be further increased. Further, when the fired product is cooled to room temperature from the firing temperature, it is moved from the heating unit to the cooling unit in the electric furnace, and rapidly cooled in a neutral atmosphere or an oxidizing atmosphere using a fan or the like to obtain a phosphor. The stimulated emission luminance can be further increased.

By utilizing the property that the alkali halide constituting the matrix of the phosphor has a high solubility in water, the phosphor of the present invention can be obtained without a firing step as described in JP-A-63-179992. Can be obtained. That is,
The phosphor raw material is weighed so as to have a mixed composition represented by the general formula, dissolved or suspended in water and sufficiently mixed, and then water is evaporated by heating, reduced pressure drying, vacuum drying, spray drying, or the like. Also by this, the phosphor of the present invention can be obtained.

Further, vapor deposition methods such as the vapor deposition method, the sputtering method, the CVD method and the ion plating method as described in JP-A-61-73100, and the stimulable phosphor and the like are previously prepared in a binder solution. The phosphor of the present invention can be obtained by a coating method in which a phosphor coating prepared by dissolving and suspending in a single layer or divided into performances is applied to a multi-layer without the firing step.

When the phosphor layer is formed by the vapor deposition method, the support is placed in the vapor deposition apparatus, and then the interior of the vapor deposition apparatus is evacuated to a vacuum degree of about 10 ^{−6 to} 10 ⁻² Torr. Then
A phosphor raw material mixture similar to that shown in the firing method is heated and evaporated by a resistance heating method, an electron beam method or the like to deposit the phosphor to a predetermined thickness on the surface of the support. Also,
It is also possible to co-evaporate the phosphor raw material using a plurality of resistance heaters or electron beams to synthesize the target phosphor on the surface of the support and simultaneously form the phosphor layer. It is also possible to form the phosphor layer by forming the phosphor base layer containing no activator on the support and then doping the activator into the phosphor base layer by a method such as a thermal diffusion method. Furthermore, during vapor deposition, a gas such as O ₂ or H ₂ may be introduced to carry out reactive vapor deposition, if necessary. In addition, the phosphor layer may be subjected to heat treatment (annealing) after the completion of vapor deposition.

When the phosphor of the present invention is used as a radiation image conversion panel, it is preferably produced by a vapor deposition method or a coating method, but an alkali halide phosphor is suitable for a vapor deposition method, It is preferable to use the vapor deposition method because the filling rate of (1) is high and the emission brightness can be improved without causing a decrease in sharpness. In the case of vapor deposition method,
The deposition rate of the phosphor layer is preferably 0.1 to 50 μm / min. If the deposition rate is too low, the productivity will be low, and if the deposition rate is too high, it will be difficult to control the deposition rate. The temperature of the support during the vapor deposition process is preferably 500 ° C or lower, and 300 ° C to 40 ° C.
0 ° C is preferred. When this temperature is too high, the sharpness of the image is likely to decrease due to the progress of crystallization.

Next, a radiation image conversion panel using the alkali halide phosphor of the present invention will be described.

FIG. 2 is a sectional view showing an example of a radiation image conversion panel, wherein 1 is a support, 2 is a phosphor layer, 3 is a low refractive index layer, 4 is a protective layer, and 5 is a spacer.

The material of the support 1 is preferably one having sufficient heat resistance during vapor deposition and subsequent heat treatment, and examples thereof include glass ceramics, alumina, quartz glass, soda glass, and aluminum.
Although the thickness of the support 1 varies depending on its material, etc., it is generally preferably 0.1 to 5 mm, which is convenient for handling.
Particularly, 0.2 to 2 mm is preferable.

The surface of the support 1 may be a smooth surface or may be a rough surface for the purpose of improving the adhesiveness with the phosphor layer 2, but the scattering of excitation light on the substrate surface is suppressed as much as possible. In order to enhance the sharpness of the obtained image, the surface roughness is preferably 0.1 μm or less, more preferably 0.01 μm or less in terms of center line average roughness: Ra (JIS B-0601). Further, the smoother the surface of the support 1, the easier it is for the phosphor layer 2 to be peeled off. Therefore, the phosphor layer 2 should be provided wider than the actual radiation image reading area, and the surface roughness of the portion other than this reading area should be increased. Is desirable. By doing so, peeling becomes difficult. As a method for adjusting the surface roughness of the support 1, there are sandblast polishing treatment, powder spraying treatment, lapping polishing treatment, etching treatment with hydrofluoric acid and the like. The surface roughness Ra of the support 1 other than the reading area is preferably 0.1 μm or more, more preferably 0.5 μm or more.

Further, an undercoat layer may be provided on the surface of the support 1 on which the phosphor layer 2 is provided for the purpose of improving the adhesiveness with the phosphor layer 2, and it is necessary to adjust the light reflectance. Depending on the case, a metal such as Al and an oxide layer such as SiO ₂ or Al ₂ O ₃ may be provided by a vacuum deposition method, a sputtering method, a thermal spraying method, or the like. Further, an undercoat layer may be provided on the surface of the support 1 on which the phosphor layer 2 is provided for the purpose of improving the adhesiveness with the phosphor layer 2, and if necessary, a light reflecting layer, a light absorbing layer. You may provide a layer etc.

The layer thickness of the phosphor layer 2 is preferably 30 to 1000 μm, and more preferably 100 to 500 μm. When the phosphor layer 2 formed by the vapor layer deposition method is subjected to heat treatment, the sensitivity to X-rays is improved. In addition, after forming a phosphor base layer containing no activator on the support 1 or the protective layer 4, the phosphor base layer is doped with an activator by a method such as a thermal diffusion method to obtain a predetermined phosphor. It can also be a layer.

The protective layer 4 is provided to protect the phosphor layer 2 physically or chemically, and it is preferable that it has good transparency and can be molded on a sheet. The protective layer 4 preferably exhibits high transmittance in a wide wavelength range in order to efficiently transmit stimulated excitation light and stimulated emission light. That is, the light transmittance is 70% in the wavelength range of 300 to 900 nm.
The above is preferable, and 90% or more is particularly preferable for the stimulated emission light of 350 to 500 nm and the stimulated excitation light of wavelength 600 to 900 nm. Examples of such materials include plate glass such as quartz, borosilicate glass, and chemically strengthened glass, and organic polymer compounds such as polyethylene terephthalate (PET), oriented polypropylene, polyvinyl chloride, and acrylic resin. Borosilicate glass shows a light transmittance of 80% or more in the wavelength range of 330 to 2600 nm, and quartz glass shows a high light transmittance even at a shorter wavelength, which is particularly preferable. Furthermore, it is preferable to provide an antireflection layer such as MgF _{2 on} the surface of the protective layer 4 because it has an effect of efficiently transmitting stimulated excitation light and stimulated emission light and enhancing sharpness. The layer thickness of the protective layer 4 is, for example, 25 μm to 5 mm, and in order to obtain good moisture resistance and impact resistance and to secure a sufficient light transmittance, it is 0.
1 to 3 mm is preferable.

The phosphor layer 2 may be in contact with both the support 1 and the protective layer 4, but the low refractive index layer 3 is provided between the phosphor layer 2 and the protective layer 4 as shown in FIG. Is preferred. The low-refractive index layer 3 exists in a state of being shielded from the external atmosphere, and the presence of the low-refractive index layer 3 substantially reduces the layer thickness of the protective layer 4 without lowering the sharpness. It is possible to increase the thickness, and the moisture resistance and durability can be further improved. Examples of such a low refractive index layer 3 include a layer made of an inert gas such as air, nitrogen, and argon, and a layer having a refractive index of substantially 1, such as a vacuum layer,
Layer made of liquid such as methyl alcohol (refractive index 1.33), ethyl alcohol (refractive index 1.36), CaF ₂ (refractive index 1.23
~ 1.26), Na ₃ AlF ₆ (refractive index 1.35), MgF ₂ (refractive index 1.3
8), SiO ₂ (refractive index 1.46) and the like. Among these, the low refractive index layer 3 composed of a gas layer or a vacuum layer is particularly preferable because it has a high effect of preventing a decrease in image sharpness. The thickness of the low refractive index layer 3 is usually 0.05 μm
~ 3mm is practical.

The spacer 5 is not particularly limited as long as it can hold the phosphor layer 2 in a state of being shielded from the external atmosphere, and examples thereof include glass, ceramics, metal and plastic.

FIG. 3 schematically shows an embodiment in which the alkali halide phosphor represented by the general formula (1) is used in the form of a radiation image conversion panel (hereinafter referred to as a conversion panel) in the radiation image conversion method of the present invention. .

The subject 102 is a conversion panel 103 and a radiation source 101.
Then, when the radiation source 101 is turned on, the transmitted radiation image of the subject 102 is recorded and accumulated in the stimulable phosphor 104 of the conversion panel 103. Thereafter, the conversion panel 103 is scanned by a stimulating excitation light source 105 such as a laser through a mirror 106, and the stimulating luminescence emitted by the stimulable phosphor 104 is transmitted to the light transmitting means 108.
The light is detected by the photodetector 107 via. At this time, the transport stage 109 sub-scans from the upper side to the lower side, for example, by the panel 103.
The total stimulated emission is detected. This time-series stimulated emission electric signal is amplified by an amplifier 111 and then amplified by an A / D converter.
It is sent to the storage means 113 through 112. Also, conversion panel 10
An erasing light source 110 is provided at a position facing the surface of the phosphor 3 on the phosphor side, and after detecting stimulated emission, the latent image accumulated in the phosphor is erased.

As the stimulated excitation light source 105, a He-Ne laser, a He-Cd laser, an Ar ion laser, a Kr ion laser, an N ₂ laser, a YAG laser and its second harmonic, a bee laser, a semiconductor laser, and various types are used. Examples include lasers such as dye lasers and metal vapor lasers such as copper vapor lasers. It is preferable that the light source for stimulated excitation light be small, have high output, and have good matching with the stimulated excitation spectrum. When the light source light includes a portion overlapping the stimulated emission spectrum, it is preferable to use a filter that cuts the spectrum portion. Furthermore, it is preferable to use a filter that transmits stimulated emission and cuts stimulated excitation light together in the photoelectric converter, and it is preferable that the photoelectric conversion system sensitivity of the photoelectric converter and the filter match the stimulated emission light well.

The erasing light source 110 is a stimulable phosphor 1.
04 is a light source that emits light including the excitation wavelength region of the phosphor, for example, a halogen lamp, a tungsten lamp, an infrared lamp, an LED as shown in JP-A-56-11392.
Alternatively, a laser light source or the like can be arbitrarily selected and used.

[0036]

EXAMPLES Examples of the present invention will be described below together with comparative examples, but the present invention is not limited to these embodiments.

Example 1 Each phosphor raw material was weighed into a combination shown in the following (1) to (17), and then thoroughly mixed using a ball mill to prepare the following phosphor raw material mixture.

[0038] (1a) RbI 212.37g (1mol) TlI 0.0331g (10 -4 mol) Pb (NO 3) 2 33.123g (10 -1 mol) (1b) RbI 212.37g (1mol) TlI 0.0331g (10 - ⁴ mol) Pb (NO ₃ ) ₂ 3.3123g (10 ^-2 mol) (1c) RbI 212.37g (1mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.3312g (10 ^-3 mol) ( 1d) RbI 212.37g (1mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.0331g (10 ^-4 mol) (1e) RbI 212.37g (1mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.0033g (10 ^-5 mol) (1f) RbI 212.37g (1mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.0003g (10 ^-6 mol) (1g) RbI 212.37 g (1mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.00003g (10 ^-7 mol) (2) KBr 119.01g (1mol) BaBr ₂ 29.716g (10 ^-1 mol) TlBr 0.0284g ( 10 ^-4 mol) PbBr ₂ 0.0367g (10 ^-4 mol) (3) CsI 259.81g (1 mol) SmCl ₃ 0.2567g (10 ^-3 mol) TlCl 0.0240g (10 ^-4 mol) (CH ₃ COO) ₂ Pb 0.0325g (10 ^-4 mol) (4) RbBr 165.38g (1 mol) SrBr ₂ 2.4744g (10 ^-2 mol) TlNO ₃ 0.0266g (10 ^-4 mol) PbI ₂ 0.0461g (10 ^-4 mol) (5) KI 83.003g (0.5mol) CsCl 84.179g (0.5mol) Tl ₂ O 0.0425g (10 ^-4 mol) Pb Cl ₂ 0.0243g (10 ^-4 mol) (6) RbI 212.37g (1mol) CeI ₃ 5.2083g (10 ^-2 mol) TlI 0.0331g (10 ^-4 mol) PbI ₂ 0.0461g (10 ^-4 mol) (7 ) KI 166.01g (1mol) MgI ₂ 27.812g (10 ^-1 mol) TlI 0.0331g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.0331g (10 ^-4 mol) (8) KCl 74.555g (1mol) CaCl ₂ 11.099g (10 ^-1 mol) TlCl 0.0240g (10 ^-4 mol) PbSO ₄ 0.0303g (10 ^-4 mol) (9) NaI 149.89g (1 mol) EuBr ₃ 0.3917g (10 ^-3 mol) TlI 0.0331g ^{(10 -4 mol) PbO 0.0223g (} 10 -4 mol) (10) RbBr 165.38g (1mol) YF 3 14.590g (10 -1 mol) TlBr 0.0284g (10 -4 mol) PbBr 2 0.0367g (10 - ⁴ mol) (11) RbCl 12092g (1mol) BeI ₂ 0.2628g (10 ^-3 mol) TlCl 0.0240g (10 ^-4 mol) PbCl 0.0243g (10 ^-4 mol) (12) NaBr 102.90g (1mol) AlBr ₃ 0.0267g (10 ^-4 mol) TlBr 0.0284g (10 ^-4 mol) PbCO ₃ 0.0267g (10 ^-4 mol) (13) PbI 212.37g (1 mol) InF ₃ 1.7182g (10 ^-2 mol) TlI 0.0331g ( 10 ^-4 mol) PbF ₂ 0.0245g (10 ^-4 mol) (14) CsBr 212.84g (1 mol) LaI ₃ 5.1962g (10 ^-2 mol) TlBr 0.0284g (10 ^-4 mol) Pb (NO ₃ ) ₂ 0.0331 g (10 ^-4 mol) (15) LiI 133.84g (1 mol) GdBr ₃ 0.0397g (10 ^-4 mol) TlI 0.0331g (10 ^-4 mol) PbI ₂ 0.0461g (10 ^-4 mol) (16) RbF 104.47g (1 mol) LuF ₃ 0.2320g (10 ^-3 mol) TlF 0.0223g ( 10 ^-4 mol) PbO ₂ 0.0239g (10 ^-4 mol) (17) KF 58.100g (1 mol) GaCl ₃ 0.0018g (10 ^-5 mol) TlF 0.0223g (10 ^-4 mol) Pb ₂ O ₃ 0.0462g ( 10 ^-4 mol) Ra: 0.001 μm of a crystallized glass plate on the surface of which a support having a light-reflecting layer made of an Al / SiO ₂ sputtered film was placed in an electron beam vapor deposition device, and then the phosphor prepared above was prepared. The raw material mixtures (1) to (17) were used as a vapor deposition source, press-molded and put in a water-cooled crucible. Then, the inside of the vapor deposition chamber was once evacuated, and then N ₂ gas was introduced to adjust the degree of vacuum to 1 × 10 ⁻³ Torr, and then the temperature of the support was kept at about 350 ° C. The surface of the vapor deposition source was scanned in a raster pattern and evaporated to deposit. The vapor deposition is terminated when the layer thickness of the phosphor layer reaches 300 μm, and then,
This phosphor layer was heat-treated at a temperature of 400 ° C. Radiation image conversion panels (1) to (17) having a structure in which a phosphor layer was sealed by encapsulating a peripheral portion of a support and a borosilicate glass in a dry air atmosphere with an adhesive were obtained. .

Each of the radiation image conversion panels was operated at a tube voltage of 80 KV _P and a tube current at a distance of 100 cm from the X-ray tube focus.
After irradiating with 10 mA X-ray for 0.1 seconds, this was excited with a semiconductor laser beam (780 nm, 10 mW), and fluorescence due to photostimulation emitted from the phosphor layer was measured with a photodetector. The results are shown in Table 1
It is shown in Table 17.

Comparative Example 1 The following phosphors (1) to (17) were prepared in the same manner as in Example 1 except that each phosphor raw material was weighed into the combinations shown in (1) to (17) below. Obtained.

(1) RbI 212.37g (1mol) TlI 0.0331g (10 ^-4 mol) (2) KBr 119.01g (1mol) BaI ₂ 39.115g (10 ^-1 mol) TlBr 0.0284g (10 ^-4 mol) ( 3) CsI 259.81g (1mol) SmCl ₃ 0.2567g (10 ^-3 mol) TlCl 0.0240g (10 ^-4 mol) (4) RbBr 165.38g (1mol) SrI ₂ 3.4143g (10 ^-2 mol) TlNO ₃ 0.0266g (10 ^-4 mol) (5) KI 83.003g (0.5mol) CsCl 84.179g (0.5mol) TlI 0.0331g (10 ^-4 mol) (6) RbI 212.37g (1mol) CeBr ₃ 3.7985g (10 ^-2 mol) ) TlI 0.0331g (10 ^-4 mol) (7) KI 166.01g (1 mol) MgI ₂ 27.812g (10 ^-1 mol) TlI 0.0331g (10 ^-4 mol) (8) KCl 74.555g (1 mol) CaCl ₂ 11.099 g (10 ^-1 mol) TlCl 0.0240g (10 ^-4 mol) (9) NaI 149.89g (1 mol) EuBr ₃ 0.3917g (10 ^-3 mol) TlI 0.0331g (10 ^-4 mol) (10) RbBr 165.38g (1mol) YF ₃ 14.590g (10 ^-1 mol) TlBr 0.0284g (10 ^-4 mol) (11) RbCl 12092g (1mol) BeI ₂ 0.2628g (10 ^-3 mol) TlCl 0.0240g (10 ^-4 mol) ( 12) NaBr 102.90g (1mol) AlBr ₃ 0.0267g (10 ^-4 mol) TlBr 0.0284g (10 ^-4 mol) (13) PbI 212.37g (1mol) InF ₃ 1.7182g (10 ^-2 mol) TlI 0.0331g ( 10 ^-4 mol) (14) CsBr 212.84g (1mol) LaI ₃ 5.1962g (10 ^-2 mol) TlBr 0.0284g (10 ^-4 mol) (15) LiI 133.84g (1mol) GdBr ₃ 0.0397g (10 ^-4 mol) TlI 0.0331g ^{(10 -4 mol) (16)} RbF 104.47g (1mol) LuF 3 0.2320g (10 -3 mol) TlF 0.0223g (10 -4 mol) (17) KF 58.100g (1mol) GaCl 3 0.0018g (10 - ⁵ mol) TlF 0.0223 g (10 ⁻⁴ mol) Using these phosphors (1) to (17), a radiation image conversion panel was obtained in the same manner as in Example 1, and a semiconductor laser was prepared in the same manner as in Example 1. The stimulated emission luminance was measured by using. The results are also shown in Tables 1 to 17.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

[0048]

[Table 7]

[0049]

[Table 8]

[0050]

[Table 9]

[0051]

[Table 10]

[0052]

[Table 11]

[0053]

[Table 12]

[0054]

[Table 13]

[0055]

[Table 14]

[0056]

[Table 15]

[0057]

[Table 16]

[0058]

[Table 17]

From Tables 1 to 17, the samples (1) to
The emission brightness of the phosphor of (17) due to photostimulation is the comparative samples (1) to (17) made of the conventionally known phosphor shown in Comparative Example 1.
The luminance is significantly higher than the emission luminance measured by the measurement.

Table 1 and FIG. 1 show the stimulated emission intensity with respect to the Pb ²⁺ content when RbI: Tl ⁺ contains Pb ²⁺ . The content of Pb ²⁺ relative to the matrix 1 of the phosphor is
It can be seen that the stimulated emission intensity becomes extremely high at 10 ^{−6 to} 10 ⁻² .

Example 2 The radiation image conversion panels (1) to (1 used in Example 1 were used.
Each of 7) was irradiated with X-rays at a tube voltage of 80 KV _P and a tube current of 10 mA for 0.1 seconds at a distance of 100 cm from the X-ray tube focus, and then a light emitting diode (680 nm) was used using a function generator.
Was excited for 5 milliseconds, and the time change (attenuation) of the stimulated emission intensity emitted from the phosphor after the excitation was stopped was measured. 5 after stopping the excitation light for the intensity immediately before stopping the excitation light
The intensity after milliseconds was defined as the photostimulable afterglow, and the results are shown in Tables 1 to 17.

Comparative Example 2 Extinction afterglow was determined in the same manner as in Example 2 except that the radiation image conversion panel used in Comparative Example 1 was used. The results are shown in Table 1.
~ Also shown in Table 17.

From Tables 1 to 17, the samples (1) to
The phosphorescence afterglow of the phosphor of (17) is much smaller than the photostimulable afterglow of the comparative samples (1) to (17) made of the conventionally known phosphor shown in Comparative Example 1.

[0064]

As described above, the phosphor of the present invention has a significantly increased stimulated emission luminance as compared with the conventional alkali halide phosphor, and the afterglow of excitation is greatly reduced. Therefore, when the radiation image conversion method using the radiation image conversion panel of the present invention is used for X-ray diagnosis or the like, it is possible to reduce the amount of X-ray exposure of the subject due to its high sensitivity, and the afterglow afterglow It is possible to improve the image quality because it is small.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the Pb ²⁺ content of the phosphor of the present invention and the emission intensity due to its stimulation.

FIG. 2 is a sectional view of a radiation image conversion panel according to an embodiment of the present invention.

FIG. 3 is a schematic view of an example of the method of the present invention for performing image conversion by using the phosphor of the present invention in the radiation image conversion panel of the present invention.

[Explanation of symbols]

 1 Support 2 Phosphor Layer 3 Low Refractive Index Layer 4 Protective Layer 5 Spacer 101 Radiation Source 103 Conversion Panel 104 Photostimulable Phosphor 105 Photostimulated Excitation Light Source 106 Mirror 107 Photodetector 108 Light Transfer Means 109 Transport Stage 110 Erase Light source 111 Amplifier 112 A / D converter 113 Storage means

Claims (21)

[Claims] 1. An alkali halide phosphor having a composition formula represented by the general formula (1). General formula (1) M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : cTl ⁺ , dPb ²⁺ (where M ¹ is at least one alkali metal selected from Li, Na, K, Rb and Cs) And M ² is Be, M
At least one divalent metal selected from g, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, L
a, Ce, Pr, Nd, Pm, Sm, En, Gd, Tb, Dy, H
at least one trivalent metal selected from o, Er, Tm, Yb, Lu, Al, Ga and In, X, X'and X "are at least one halogen selected from F, Cl, Br and I. there. Furthermore, a, b, c and d are each 0 ≦ a ≦ 0.3,0 ≦ b ≦ 0.3,10 -6 ≦ c ≦ 10 -2, 10 -6
It is a numerical value in the range of ≤d≤10 ^-2 . ) 2. M ¹ in the general formula (1) is K, Rb
The alkali halide phosphor according to claim 1, which is at least one alkali metal selected from Cs and Cs. 3. The alkali halide phosphor according to claim 1, wherein X in the general formula (1) is at least one halogen selected from Br and I. 4. M ² in the general formula (1) is Be, M
4. At least one divalent metal selected from g, Ca, Sr and Ba, according to any one of claims 1 to 3.
The alkali halide phosphor according to the item 1. 5. M ³ in the general formula (1) is Y, C.
The alkali halide phosphor according to any one of claims 1 to 4, which is at least one trivalent metal selected from e, Sm, Eu, Al, La, Gd, Lu, Ga and In. . 6. b in the general formula (1) is 0 ≦ b ≦
The alkali halide phosphor according to any one of claims 1 to 5, which is 10 ^-2 . 7. d in the general formula (1) is 10 ⁻⁵ ≦ d
≦ 10 ⁻³ , any one of claims 1 to 6 characterized in that
The alkali halide phosphor according to the item 1. 8. In a radiation image conversion panel having a support and at least one phosphor layer provided on the support, at least one of the phosphor layers is represented by the following general formula (1). A radiation image conversion panel comprising an alkali halide phosphor. General formula (1) M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : cTl ⁺ , dPb ²⁺ (where M ¹ is at least one alkali metal selected from Li, Na, K, Rb and Cs) And M ² is Be, M
At least one divalent metal selected from g, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
at least one trivalent metal selected from o, Er, Tm, Yb, Lu, Al, Ga and In, X, X'and X "are at least one halogen selected from F, Cl, Br and I. there. Furthermore, a, b, c and d are each 0 ≦ a ≦ 0.3,0 ≦ b ≦ 0.3,10 -6 ≦ c ≦ 10 -2, 10 -6
It is a numerical value in the range of ≤d≤10 ^-2 . ) 9. M ¹ in the general formula (1) is K, Rb
The radiation image conversion panel according to claim 8, wherein the radiation image conversion panel is at least one alkali metal selected from Cs and Cs. 10. The radiation image conversion panel according to claim 8 or 9, wherein X in the general formula (1) is at least one kind of halogen selected from Br and I. 11. M ² in the general formula (1) is Be,
The radiation image conversion panel according to any one of claims 8 to 10, which is at least one divalent metal selected from Mg, Ca, Sr, and Ba. 12. M ³ in the general formula (1) is Y,
The radiation image conversion panel according to any one of claims 8 to 11, which is at least one trivalent metal selected from Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In. . 13. In the general formula (1), b is 0 ≦ b.
≦ 10 ⁻² , any one of claims 8 to 12 characterized in that
The radiation image conversion panel according to item. 14. d in the general formula (1) is 10 ⁻⁵ ≦
14. The radiation image conversion panel according to claim 8, wherein d ≦ 10 ⁻³ . 15. A radiation image is radiated to a subject, and the radiation transmitted through the subject is applied to a radiation image conversion panel having a phosphor layer so that the radiation energy is imaged on the radiation image conversion panel. Accumulation record,
In the radiation image conversion method of stimulating the accumulated and recorded radiation energy by exciting light with excitation light to convert into stimulated light, at least one of the phosphor layers is regenerated.
A radiation image conversion method comprising an alkali halide phosphor represented by the following general formula (1). General formula (1) M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : cTl ⁺ , dPb ²⁺ (where M ¹ is at least one alkali metal selected from Li, Na, K, Rb and Cs) And M ² is Be, M
At least one divalent metal selected from g, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, L
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, H
at least one trivalent metal selected from o, Er, Tm, Yb, Lu, Al, Ga and In, X, X'and X "are at least one halogen selected from F, Cl, Br and I. there. Furthermore, a, b, c and d are each 0 ≦ a ≦ 0.3,0 ≦ b ≦ 0.3,10 -6 ≦ c ≦ 10 -2, 10 -6
It is a numerical value in the range of ≤d≤10 ^-2 . ) 16. M ¹ in the general formula (1) is K,
16. The radiation image conversion method according to claim 15, wherein the radiation image conversion is at least one kind of alkali metal selected from Rb and Cs. 17. The radiographic image conversion method according to claim 15, wherein X in the general formula (1) is at least one halogen selected from Br and I. 18. M ² in the general formula (1) is Be,
18. The radiation image conversion method according to claim 15, wherein the radiation image conversion is at least one divalent metal selected from Mg, Ca, Sr and Ba. 19. M ³ in the general formula (1) is Y,
The radiation image conversion method according to any one of claims 15 to 18, which is at least one trivalent metal selected from Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In. . 20. In the general formula (1), b is 0 ≦ b
20. ≦ 10 ⁻² , wherein any one of claims 15 to 19 is satisfied.
The radiographic image conversion method according to item. 21. d in the general formula (1) is 10 ⁻⁵ ≦
21. The radiographic image conversion method according to claim 15, wherein d ≦ 10 ⁻³ .