JP2005106771A - Radiation image conversion panel and manufacturing method for it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel whose warpage is reduced and which is excellent in resistance to impact in and to provide a manufacturing method for the panel. <P>SOLUTION: The radiation image conversion panel includes a stimulable phosphor layer 12 containing stimulable phosphors on a support 11 by a gas phase lay-up method. Moreover, the distribution of the first peak intensity showing the maximum intensity in an X-ray diffraction pattern inside a stimulable phosphor layer face is isotropic from the center of the support 11. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a radiation image conversion panel provided with a stimulable phosphor layer containing a stimulable phosphor on a support by a vapor deposition method, and a method for producing the radiation image conversion panel.

Conventionally, so-called radiography using a silver salt is used to obtain a radiographic image, but a method for imaging a radiographic image without using a silver salt has been developed. That is, the radiation transmitted through the subject is absorbed by the stimulable phosphor, and then the stimulable phosphor is excited with a certain energy to excite the radiation energy accumulated in the stimulable phosphor. A method of emitting as a fluorescent material and detecting and imaging this fluorescence is disclosed.
As a specific method, a radiation image conversion method using a panel having a photostimulable phosphor layer on a support and using one or both of visible light and infrared light as excitation energy is known (Patent Document 1). reference).

  By the way, in recent years, as a radiation image conversion method using a high-luminance, high-sensitivity, high-sharp stimulable phosphor, radiation using a stimulable phosphor in which Eu is activated with an alkali halide such as CsBr as a base material. An image conversion panel has been proposed. In particular, by using Eu as an activator, X-ray conversion efficiency, which has been impossible in the past, can be improved.

On the other hand, there is a demand for a radiation image conversion panel with higher sensitivity in the analysis of diagnostic images. As a means for this, for example, the crystal structure of the photostimulable phosphor layer formed by vapor deposition is a cesium chloride type structure. A phosphor layer made of a phosphor has been proposed in which the main growth direction is defined as the (110) or (100) direction (see Patent Document 2).
US Pat. No. 3,859,527 JP 2003-107160 A

  However, the radiation image conversion panel described in Patent Document 2 only describes the crystal growth direction of the crystal structure of the stimulable phosphor layer, and exhibits maximum intensity at different positions from the center of the support. The first peak intensity appeared and the first peak intensity distribution was not isotropic. For this reason, the distribution of heat and the distribution of residual stress are not uniform and cannot be uniformly dispersed, so that there is a problem that the panel is warped along a certain direction or impact resistance is lowered.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method of the radiation image conversion panel which reduced the curvature of the panel, and was excellent in impact resistance, and a radiation image conversion panel.

In order to solve the above problems, the invention of claim 1 is a radiation image conversion panel comprising a stimulable phosphor layer containing a stimulable phosphor on a support by a vapor deposition method,
The first peak intensity distribution showing the maximum intensity in the X-ray diffraction pattern in the surface of the photostimulable phosphor layer is isotropic from the center of the support.

  According to the invention of claim 1, since the distribution of the first peak intensity is isotropic from the center of the support, the crystallinity is isotropic, and the heat distribution and the stress distribution are isotropic and evenly distributed. can do. Therefore, the warpage of the panel can be reduced and the impact resistance is excellent. Therefore, the image quality of the radiation image can be improved.

The invention of claim 2 is the radiation image conversion panel according to claim 1,
The variation coefficient of the first peak intensity is 40% or less.

  According to the invention of claim 2, since the coefficient of variation of the first peak intensity is 40% or less, the first peak intensity distribution is made substantially uniform in the in-plane direction, the panel warpage can be further reduced, and the impact resistance The sex can also be enhanced.

The invention of claim 3 is the radiation image conversion panel according to claim 1,
The variation coefficient of the first peak intensity is 30% or less.

The invention of claim 4 is the radiation image conversion panel according to claim 1,
The variation coefficient of the first peak intensity is 20% or less.

The invention of claim 5 is the radiation image conversion panel according to claim 1,
The variation coefficient of the first peak intensity is 10% or less.

Invention of Claim 6 is a radiation image conversion panel as described in any one of Claims 1-5.
The plane index of the first peak is (x, 0, 0) plane [x = 1, 2, 3].

  According to the invention of claim 6, since the plane index of the first peak is the (x, 0, 0) plane [x = 1, 2, 3], the radiation image conversion panel having a very high sensitivity can be obtained. it can.

The invention of claim 7 is the radiation image conversion panel according to claim 6,
In the (x, 0, 0) plane which is the plane index of the first peak, x = 2.

Invention of Claim 8 is the radiation image conversion panel as described in any one of Claims 1-7,
The photostimulable phosphor layer contains a photostimulable phosphor based on an alkali halide represented by the following general formula (1).
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA (1)
[Wherein, M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu. And at least one divalent metal atom selected from each atom of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal atom selected from each atom of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least selected from each atom of F, Cl, Br and I 1 type of halogen atom, A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. At least one metal atom selected from each atom, and a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e <1.0.]

  According to the invention of claim 8, since the photostimulable phosphor layer is based on the alkali halide represented by the general formula (1), the photostimulable phosphor layer having both high sensitivity and high sharpness. And the image quality of the radiation image can be significantly improved.

The invention of claim 8 is a vacuum vessel, an evaporation source that is provided in the vacuum vessel and deposits a stimulable phosphor on a support, and supports the support and rotates with respect to the evaporation source. The radiation image conversion panel according to any one of claims 1 to 7 is manufactured by using a vapor deposition apparatus provided with a support rotating mechanism for vapor-depositing a stimulable phosphor from the evaporation source. A method for manufacturing a radiation image conversion panel, comprising:
The stimulable phosphor layer evaporating from the evaporation source is deposited on the support by supporting and rotating the support by the support rotating mechanism to form a stimulable phosphor layer. Features.

According to the invention of claim 8, by supporting and rotating the support by the support rotating mechanism, the stimulable phosphor evaporating from the evaporation source is deposited on the support to form the stimulable phosphor layer. As a result, the photostimulable phosphor layer is uniformly formed on the support.
In addition, since the photostimulable phosphor is deposited by rotating the support, the residual stress remaining at the time of deposition is uniformly dispersed, the panel warpage can be reduced, and the impact resistance is excellent. Therefore, the image quality of the radiation image can be improved.

According to the radiation image conversion panel and the method for manufacturing the radiation image conversion panel according to the present invention, the distribution of the first peak intensity is isotropic from the center of the support, so that the crystallinity becomes isotropic, The stress distribution is isotropic and can be evenly distributed. Therefore, the warpage of the panel can be reduced and the impact resistance is excellent.
In addition, since the stimulable phosphor is deposited by rotating the support, a stimulable phosphor layer is uniformly formed on the support, and also in this respect, the warpage of the panel can be reduced and the impact resistance is improved. Excellent.

Hereinafter, the radiation image conversion panel and the method for manufacturing the radiation image conversion panel according to the present invention will be described in detail.
As shown in FIG. 1, the radiation image conversion panel of the present invention includes a support 11 and a stimulable phosphor layer 12 formed on the support 11 and containing a stimulable phosphor. Moreover, the protective layer which protects the photostimulable phosphor layer 12 is provided as needed. In the photostimulable phosphor layer 12, a gap 14 is formed between the columnar crystals 13 of the photostimulable phosphor.

  The inventors of the present invention have made the isotropic crystallinity by making the distribution of the first peak intensity showing the maximum intensity in the X-ray diffraction pattern in the stimulable phosphor layer plane isotropic from the center of the support. As a result, it was found that the heat distribution and stress distribution are isotropic and evenly distributed, the panel warpage can be reduced, and the impact resistance is excellent.

Here, the X-ray diffraction pattern is a case where the X-ray diffraction apparatus measures the X-ray incident angle in a range from 20 ° to 70 °.
In addition, the distribution of the first peak intensity is isotropic from the center of the support, as shown in FIG. 5 (a), is the first peak that is substantially concentric (at approximately the same distance from the support center). This means that the strengths of are substantially equal. On the contrary, being anisotropic means a state in which the intensity of the first peak on the illustrated line is equal, as shown in FIGS. 5B and 5C, for example, from the center of the support. This means that the intensities of the first peaks on substantially concentric circles are not equal.

Further, from the viewpoint of obtaining the effect of the present invention, the variation coefficient of the first peak intensity is preferably 40% or less.
The coefficient of variation is preferably 30% or less, more preferably 20% or less, and most preferably 10% or less.
The variation coefficient mentioned here is “variation coefficient = standard deviation of first peak intensity in plane / average of first peak intensity”.

  The plane index of the first peak is preferably an (x, 0, 0) plane [x = 1, 2, 3], and particularly preferably x = 2.

The support used in the present invention can be arbitrarily selected from known materials as a support for a conventional radiation image conversion panel. However, in the case of forming a phosphor layer by a vapor deposition method, In particular, a quartz glass sheet, a metal sheet made of aluminum, iron, tin, chromium, or the like, and a carbon fiber reinforced sheet are preferable.
The support preferably has a resin layer in order to make the surface smooth.
The resin layer preferably contains a compound such as polyimide, polyethylene terephthalate, paraffin, graphite, and the film thickness is preferably about 5 μm to 50 μm. This resin layer may be provided on the front surface, the back surface, or both surfaces of the support.
Examples of means for providing the resin layer on the support include means such as a bonding method and a coating method.
Bonding is performed using heating and a pressure roller, and the heating condition is preferably about 80 to 150 ° C., the pressing condition is 4.90 × 10 to 2.94 × 10 ² N / cm, and the conveyance speed is 0. .1 to 2.0 m / sec is preferable.

  The film thickness of the photostimulable phosphor layer of the present invention is 50 μm to 2000 μm from the viewpoint of obtaining the effects of the present invention, although it varies depending on the intended use of the radiation image conversion panel and the type of stimulable phosphor. Preferably they are 50 micrometers-1000 micrometers, More preferably, they are 100 micrometers-800 micrometers.

The stimulable phosphor layer preferably contains a stimulable phosphor represented by the following general formula (1).
General formula (1)
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA [wherein M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms; ² is at least one divalent metal atom selected from the atoms of Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu and Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd. , Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In, at least one trivalent metal atom, and X, X ′, X ″ is at least one halogen atom selected from F, Cl, Br, and I atoms, and A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd , Lu, Sm, Y, Tl, Na, Ag, Cu and Mg It is at least one kind of metal atom, and a, b and e each represent a numerical value in the range of 0 ≦ a <0.5, 0 ≦ b <0.5, and 0 <e ≦ 0.2. ]

In the photostimulable phosphor represented by the general formula (1), M ¹ represents at least one alkali metal atom selected from each atom such as Na, K, Rb and Cs. At least one alkaline earth metal atom selected from each atom is preferred, and a Cs atom is more preferred.

M ² represents at least one divalent metal atom selected from atoms such as Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu, and Ni, and among these, Be, It is a divalent metal atom selected from each atom such as Mg, Ca, Sr and Ba.

M ³ is selected from atoms such as Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In. At least one trivalent metal atom is represented, but among them, a trivalent metal atom selected from each atom such as Y, Ce, Sm, Eu, Al, La, Gd, Lu, Ga and In is preferable. It is.

  A is at least one selected from each atom of Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu, and Mg. It is a seed metal atom.

  From the viewpoint of improving the photostimulable emission luminance of the photostimulable phosphor, X, X ′ and X ″ represent at least one halogen atom selected from F, Cl, Br and I atoms. At least one halogen atom selected from Br is preferable, and at least one halogen atom selected from Br and I atoms is more preferable.

In the general formula (1), the b value is 0 ≦ b <0.5, and preferably 0 ≦ b <10 ⁻² .

In particular, in the present invention, it is preferable to use a stimulable phosphor having, as a base, CsBr which is a combination of atoms (M ¹ ; Cs, X; Br) in the general formula (1).

The photostimulable phosphor represented by the general formula (1) of the present invention is produced, for example, by the method described below.
As a phosphor material,
(A) At least one compound selected from NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbF, RbCl, RbBr, RbI, CsF, CsCl, CsBr and CsI is used.

_{(B) MgF 2, MgCl 2} , MgBr 2, MgI 2, CaF 2, CaCl 2, CaBr 2, CaI 2, SrF 2, SrCl 2, SrBr 2, SrI 2, BaF 2, BaCI 2, BaBr 2, BaBr 2 2H ₂ O, BaI ₂ , ZnF ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , CdF ₂ , CdCl ₂ , CdBr ₂ , CdI ₂ , CuF ₂ , CuCl ₂ , CuBr ₂ , CuI, NiF ₂ , NiCl ₂ , NiBr _At least one or two or more compounds selected from ₂ and NiI ₂ compounds are used.

  (C) In the general formula (1), Eu, Tb, In, Cs, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu And a compound having a metal atom selected from each atom such as Mg.

The phosphor materials (a) to (c) are weighed so as to have a mixed composition in the above numerical range, and dissolved in pure water.
At this time, the mixture may be sufficiently mixed using a mortar, ball mill, mixer mill or the like.
Next, a predetermined acid is added so that the pH value C of the obtained aqueous solution is adjusted to 0 <C <7, and then water is evaporated.
Next, the obtained 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 preferably 500 to 1000 ° C. The firing time varies depending on the filling amount of the raw material mixture, the firing temperature and the like, but is preferably 0.5 to 6 hours.
The firing atmosphere includes a nitrogen gas atmosphere containing a small amount of hydrogen gas, a weak reducing atmosphere such as a carbon dioxide gas atmosphere containing a small amount of carbon monoxide, a neutral atmosphere such as a nitrogen gas atmosphere and an argon gas atmosphere, or a small amount of oxygen gas. A weak oxidizing atmosphere is preferred.

  After firing once under the aforementioned firing conditions, the fired product is taken out from the electric furnace and pulverized, and then the fired product powder is again filled in a heat-resistant container and placed in the electric furnace, and again under the same firing conditions as described above. If the firing is performed, the luminous brightness of the photostimulable phosphor can be further increased, and when the fired product is cooled to the room temperature from the firing temperature, the fired product is taken out of the electric furnace and allowed to cool in the air. Although the desired photostimulable phosphor can be obtained, it may be cooled in the same weakly reducing atmosphere or neutral atmosphere as in the firing.

  In addition, by moving the fired product from the heating part to the cooling part in an electric furnace and quenching in a weakly reducing atmosphere, neutral atmosphere or weakly oxidizing atmosphere, the resulting stimulable phosphor is excited. The emission luminance can be further increased, which is preferable.

The photostimulable phosphor layer of the present invention is formed by a vapor deposition method.
As the vapor phase deposition method of the photostimulable phosphor, an evaporation method, a sputtering method, a CVD method, an ion plating method, and others can be used. In the present invention, the evaporation method is particularly preferable.

Hereinafter, the vapor deposition method suitable for the present invention will be described. Here, since the stimulable phosphor is deposited on the support using the deposition apparatus shown in FIG. 3, it will be described together with the description of the deposition apparatus.
As shown in FIG. 3, the vapor deposition apparatus 1 includes a vacuum vessel 2, an evaporation source 3 that is provided in the vacuum vessel 2 and deposits vapor on the support 11, and a support holder 4 that holds the support 11. A support rotating mechanism 5 for depositing vapor from the evaporation source 3 by rotating the support holder 4 with respect to the evaporation source 3, a vacuum pump 6 for introducing the exhaust in the vacuum vessel 2 and introducing the atmosphere, etc. It has.

Since the evaporation source 3 contains a stimulable phosphor and is heated by a resistance heating method, the evaporation source 3 may be composed of an alumina crucible around which a heater is wound, or a boat or a heater made of a refractory metal. May be. In addition to the resistance heating method, the stimulable phosphor may be heated by an electron beam or a high frequency induction method. However, in the present invention, it is easy to handle with a relatively simple structure and is inexpensive. In addition, the resistance heating method is preferable because it can be applied to a large number of substances. The evaporation source 3 may be a molecular beam source by a molecular source epitaxial method.
The support rotation mechanism 5 includes, for example, a rotation shaft 5a that supports the support holder and rotates the support holder 4, a motor (not shown) that is disposed outside the vacuum vessel 2 and serves as a drive source for the rotation shaft 5a, and the like. It is composed of
The support holder 4 is preferably provided with a heater (not shown) for heating the support 11. By heating the support 11, the adsorbate on the surface of the support 11 is separated and removed, and the generation of an impurity layer between the surface of the support 11 and the photostimulable phosphor is prevented, the adhesion is enhanced and the brightness is increased. The film quality of the stimulable phosphor layer can be adjusted.
Furthermore, a shutter (not shown) that blocks a space from the evaporation source 3 to the support 11 may be provided between the support 11 and the evaporation source 3. Substances other than the target substance attached to the surface of the photostimulable phosphor by the shutter can be prevented from evaporating at the initial stage of vapor deposition and adhering to the support 11.

In order to form the photostimulable phosphor layer on the support 11 using the vapor deposition apparatus 1 configured as described above, first, the support 11 is attached to the support holder 4.
Next, the vacuum container 2 is evacuated. Thereafter, the support holder 4 is rotated with respect to the evaporation source 3 by the support rotating mechanism 5, and when the vacuum container 2 reaches a vacuum degree capable of vapor deposition, the stimulable phosphor is evaporated from the heated evaporation source 3. Then, a stimulable phosphor is grown on the surface of the support 11 to a desired thickness. In this case, the distance between the support 11 and the evaporation source 3 is preferably set to 100 mm to 1500 mm.

The stimulable phosphor used as the evaporation source is preferably processed into a tablet shape by pressure compression.
Further, instead of the photostimulable phosphor, a raw material or a raw material mixture may be used.

FIG. 2 is a diagram showing a specific state in which the photostimulable phosphor layer 12 is formed on the support 11 by vapor deposition. The incident angle of the vapor flow 15 of the stimulable phosphor with respect to the normal direction (R) of the surface of the support 11 fixed to the support holder 4 is θ ₂ (60 ° in the figure), and the columnar crystals 13 formed Assuming that the angle with respect to the normal direction (R) of the support surface is θ ₁ (30 ° in the figure), θ ₁ is empirically about half of θ ₂ , and the columnar crystal 13 is formed at this angle. In FIG. 3, the incident angle θ ₂ of the vapor flow 15 is set to 0 °.
Here, the photostimulable phosphor layer 12 containing no binder is formed. However, the gap 14 formed between the columnar crystals 13 may be filled with a filler such as a binder. In addition to reinforcing the phosphor layer 12, a highly light-absorbing substance and a highly reflecting substance may be filled. In addition to providing a reinforcing effect, this is effective in reducing the light diffusion in the lateral direction of the photostimulated excitation light incident on the photostimulable phosphor layer 12.

  In the vapor deposition step, the photostimulable phosphor layer can be formed in a plurality of times. Further, in the vapor deposition step, it is possible to co-evaporate using a plurality of resistance heaters or electron beams to synthesize the desired photostimulable phosphor on the support and simultaneously form the photostimulable phosphor layer. is there.

In the vapor deposition method, the vapor deposition target (support, protective layer, or intermediate layer) may be cooled or heated as necessary during vapor deposition.
Further, the stimulable phosphor layer may be heat-treated after the vapor deposition. In the vapor deposition method, reactive vapor deposition may be performed in which vapor deposition is performed by introducing a gas such as O ₂ or H _{2 as} necessary.

  In forming the photostimulable phosphor layer by the vapor deposition method, the temperature of the support on which the photostimulable phosphor layer is formed is preferably set to room temperature (rt) to 300 ° C., more preferably 50-200 ° C.

  As described above, after forming the photostimulable phosphor layer including the layer of the particulate crystal structure and the layer of the columnar crystal structure, the opposite of the support of the photostimulable phosphor layer is performed as necessary. The radiation image conversion panel of the present invention is manufactured by providing a protective layer on the side. The protective layer may be formed by directly applying a coating solution for the protective layer to the surface of the photostimulable phosphor layer, or a protective layer separately formed in advance may be adhered to the photostimulable phosphor layer. .

  Materials for the protective layer include cellulose acetate, nitrocellulose, polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyester, polyethylene terephthalate, polyethylene, polyvinylidene chloride, nylon, polytetrafluoroethylene, polytrifluoride-chloride. Usual protective layer materials such as ethylene, ethylene tetrafluoride-hexafluoropropylene copolymer, vinylidene chloride-vinyl chloride copolymer, vinylidene chloride-acrylonitrile copolymer are used. In addition, a transparent glass substrate can be used as the protective layer.

Further, this protective layer may be formed by laminating inorganic substances such as SiC, SiO ₂ , SiN, Al ₂ O ₃ by vapor deposition, sputtering, or the like. The thickness of these protective layers is preferably 0.1 μm to 2000 μm.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, the embodiment of this invention is not limited to this.
Radiation image conversion panels of Examples 1 to 4, Comparative Example 1, and Comparative Example 2 were produced according to the following method.
[Example 1]
(Production of radiation image conversion panel)
A stimulable phosphor layer was formed by depositing a stimulable phosphor (CsBr: 0.0002Eu) on one side of a support made of a carbon fiber reinforced resin sheet using the deposition apparatus 1 shown in FIG.
That is, first, the phosphor raw material was filled in a resistance heating crucible as an evaporation material, and the support 11 was placed on the rotating support holder 4, and the distance between the support 11 and the evaporation source 3 was adjusted to 300 mm. Subsequently, the inside of the vapor deposition apparatus 1 was once evacuated, Ar gas was introduced and the degree of vacuum was adjusted to 0.1 Pa, and then the temperature of the support 11 was maintained at 100 ° C. while rotating the support 11 at a speed of 10 rpm. . Next, the resistance heating crucible was heated to deposit a stimulable phosphor, and the deposition was terminated when the thickness of the stimulable phosphor layer reached 500 μm.
Next, the stimulable phosphor layer was placed in a protective layer bag in dry air to obtain a radiation image conversion panel having a structure in which the stimulable phosphor layer was sealed.
The radiation image conversion panel obtained at this time had an isotropic film thickness distribution. Further, the X-ray diffraction measurement was performed on the radiation image conversion panel using an X-ray diffractometer (JDX-11RA manufactured by JEOL Ltd.) to obtain an X-ray diffraction pattern. 0) plane. The in-plane variation coefficient of the first peak intensity was 57%. The coefficient of variation was determined by the above formula. The peak showing the maximum intensity was defined as the first peak.

[Example 2]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 400 mm. At this time, the obtained radiation image conversion panel has an isotropic film thickness distribution, the first peak has a (1, 0, 0) plane index, and the in-plane variation coefficient of the first peak intensity is 37. %Met.

[Example 3]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 600 mm. At this time, the obtained radiation image conversion panel has an isotropic film thickness distribution, the plane index of the first peak is (2, 0, 0) plane, and the in-plane variation coefficient of the first peak intensity is 25. %Met.

[Example 4]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 800 mm. At this time, the plane index of the first peak of the obtained radiation image conversion panel was (2, 0, 0) plane, and the in-plane variation coefficient of the first peak intensity was 16%.

[Example 5]
A radiation image conversion panel was produced in the same manner as in Example 1 except that the distance between the support and the evaporation source was adjusted to 1000 mm. At this time, the plane index of the first peak of the obtained radiation image conversion panel was (2, 0, 0) plane, and the in-plane variation coefficient of the first peak intensity was 4%.

[Comparative Example 1]
A stimulable phosphor layer was formed by depositing a stimulable phosphor (CsBr: 0.0002Eu) on one side of a support made of a carbon fiber reinforced resin sheet using the deposition apparatus 1A shown in FIG.
That is, first, the resistance heating crucible was filled with the phosphor raw material as a vapor deposition material, and the support 11 was placed on the support holder 4A, and the distance between the support 11 and the evaporation source 3A was set to 400 mm.
Subsequently, the inside of the vapor deposition apparatus 1A is once evacuated, Ar gas is introduced and the degree of vacuum is adjusted to 0.1 Pa, and then the support 11 is transported by the support transport mechanism 5A in the horizontal direction with respect to the evaporation source 3A. The temperature of the support 11 was kept at 100 ° C. Next, the resistance heating crucible was heated to deposit a stimulable phosphor, and the deposition was terminated when the thickness of the stimulable phosphor layer reached 500 μm. In FIG. 4, 2A denotes a vacuum container, 6A denotes a slit, 7A denotes a deposition preventing plate, and 8A denotes a vacuum pump.
Next, the stimulable phosphor layer was placed in a protective layer bag in dry air to obtain a radiation image conversion panel having a structure in which the stimulable phosphor layer was sealed.
The radiation image conversion panel obtained at this time had an anisotropic film thickness distribution. Further, the plane index of the first peak was the (2, 0, 0) plane, and the in-plane variation coefficient of the first peak intensity was 53%.

[Comparative Example 2]
A radiation image conversion panel was produced in the same manner as in Comparative Example 1 except that the distance between the support and the evaporation source was adjusted to 1000 mm. At this time, the plane index of the first peak of the obtained radiation image conversion panel was (2, 0, 0), and the in-plane variation coefficient of the first peak intensity was 41%.

And the following evaluation was performed about the radiation image conversion panel obtained as mentioned above.
《Panel warpage》
The amount of warpage of the radiation image conversion panel is measured with the gap gauge on the upper two corners when the radiation image conversion panel is leaned against a stainless steel plate with good straightness at an angle of 5 ° and the other two corners by rotating 180 °. The maximum value was taken as the amount of warpage (mm). Table 1 shows the results.

《Shock resistance》
After dropping a 500 g iron ball from a height position 20 cm away from the radiation image conversion panel, the radiation image conversion panel was visually evaluated. Thereafter, each radiation image conversion panel is irradiated with X-rays having a tube voltage of 80 kVp from the back side of the support, and then the radiation image conversion panel is excited by scanning with a He—Ne laser beam (633 nm) to produce stimulable fluorescence. Stimulated luminescence emitted from the body layer is received by a light receiver (photomultiplier tube with spectral sensitivity S-5) and converted into an electrical signal, which is reproduced as an image by an image reproducing device and printed out from an output device. Then, the obtained printed image was visually evaluated for impact resistance according to the following criteria. Table 1 shows the results.
(Double-circle): There is no crack and it is a uniform image.
○: There is no crack, and the image quality is hardly a concern.
(Triangle | delta): Although a crack is seen and a notch is confirmed, it is a level acceptable practically.
X: Cracks are observed, clear omissions are observed, and practically problematic.

以上、表１の結果から明らかなように、輝尽性蛍光体層面内の第１ピーク強度の分布が支持体中心から等方的に実施例１〜実施例５は、第１ピーク強度の分布が異方的な比較例１、比較例２に比べて、パネルの反りが極めて少なく、耐衝撃性についてもその評価が△以上であり実用上許容できるレベルであった。
また、蒸着装置についても図４に示すように支持体を水平方向に搬送することによって蒸着する搬送方式に比べて、図３に示すように支持体を回転することによって蒸着する回転方式の方が、支持体上に輝尽性蛍光体層を均一に蒸着させることができ、この点においてもパネルの反りを防ぐことができることがわかる。
また、第１ピーク強度の変動係数が４０％以下である実施例２〜実施例５は、変動係数が４０％を越える比較例１、比較例２に比べて、パネルの反りを低減でき、耐衝撃性に強いことがわかる。
また、特に、第１ピーク強度の変動係数が最も小さい実施例５の結果から、変動係数が小さい程、パネルの反り防止及び耐衝撃性に有利であることがわかる。
さらに、第１ピークの面指数が（１，０，０）面である実施例１、実施例２に比べて、第１ピークの面指数が（２，０，０）面である実施例３〜実施例５の方が第１ピーク強度の変動係数を小さく抑えることができ、本発明の効果に有利であることがわかる。

As is apparent from the results of Table 1, the distribution of the first peak intensity in the stimulable phosphor layer surface is isotropic from the center of the support in Examples 1 to 5. Compared with the comparative examples 1 and 2 which are anisotropic, the warpage of the panel is extremely small, and the evaluation of the impact resistance is Δ or more, which is a practically acceptable level.
Also, as for the vapor deposition apparatus, the rotation method for vapor deposition by rotating the support body as shown in FIG. 3 is better than the conveyance method for vapor deposition by conveying the support body in the horizontal direction as shown in FIG. It can be seen that the photostimulable phosphor layer can be uniformly deposited on the support, and the warpage of the panel can be prevented also in this respect.
Further, Examples 2 to 5 in which the coefficient of variation of the first peak intensity is 40% or less can reduce the warpage of the panel as compared with Comparative Examples 1 and 2 in which the coefficient of variation exceeds 40%. It turns out that it is strong in impact.
In particular, it can be seen from the results of Example 5 that the coefficient of variation of the first peak intensity is the smallest, the smaller the coefficient of variation, the more advantageous for the panel warpage prevention and impact resistance.
Further, in comparison with Example 1 and Example 2 in which the plane index of the first peak is the (1, 0, 0) plane, Example 3 in which the plane index of the first peak is the (2, 0, 0) plane. It can be seen that Example 5 is more advantageous for the effect of the present invention because the variation coefficient of the first peak intensity can be reduced.

  Therefore, by making the intensity distribution of the first peak intensity isotropic from the center of the support in the X-ray diffraction pattern in the photostimulable phosphor layer surface, it is possible to reduce the warp of the panel and improve the impact resistance. It becomes. Moreover, the effect of this invention can be improved further by making the variation coefficient of 1st peak intensity | strength 40% or less.

It is a schematic sectional drawing which shows an example of the photostimulable phosphor layer formed on the support body. It is a figure which shows a mode that a photostimulable phosphor layer is formed on a support body by a vapor deposition method. It is sectional drawing which shows schematic structure of the vapor deposition apparatus by a rotation system. It is sectional drawing which shows schematic structure of the vapor deposition apparatus by a conveyance system. (a) is a diagram for explaining that the distribution of the first peak intensity is isotropic from the center of the support, and (b) and (c) are diagrams showing that the distribution of the first peak intensity is different from the support center. It is a figure for demonstrating that it is direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposition apparatus 2 Vacuum container 3 Evaporation source 5 Support body rotation mechanism 11 Support body 12 Stimulable phosphor layer

Claims (9)

A radiation image conversion panel comprising a stimulable phosphor layer containing a stimulable phosphor on a support by vapor deposition,
The radiation image conversion panel, wherein the first peak intensity distribution showing the maximum intensity in the X-ray diffraction pattern in the surface of the photostimulable phosphor layer is isotropic from the center of the support.   The radiation image conversion panel according to claim 1, wherein a variation coefficient of the first peak intensity is 40% or less.   The radiation image conversion panel according to claim 1, wherein a variation coefficient of the first peak intensity is 30% or less.   The radiation image conversion panel according to claim 1, wherein a variation coefficient of the first peak intensity is 20% or less.   The radiation image conversion panel according to claim 1, wherein a variation coefficient of the first peak intensity is 10% or less.   6. The radiation image conversion panel according to claim 1, wherein the plane index of the first peak is an (x, 0, 0) plane [x = 1, 2, 3].   The radiation image conversion panel according to claim 6, wherein x = 2 in the (x, 0, 0) plane which is the plane index of the first peak. The photostimulable phosphor layer contains a photostimulable phosphor based on an alkali halide represented by the following general formula (1). The radiation image conversion panel described.
M ¹ X · aM ² X ′ ₂ · bM ³ X ″ ₃ : eA (1)
[Wherein, M ¹ is at least one alkali metal atom selected from Li, Na, K, Rb and Cs atoms, and M ² is Be, Mg, Ca, Sr, Ba, Zn, Cd, Cu. And at least one divalent metal atom selected from each atom of Ni, and M ³ is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, At least one trivalent metal atom selected from each atom of Tm, Yb, Lu, Al, Ga and In, and X, X ′ and X ″ are at least selected from each atom of F, Cl, Br and I 1 type of halogen atom, A is Eu, Tb, In, Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Gd, Lu, Sm, Y, Tl, Na, Ag, Cu and Mg. At least one metal atom selected from each atom, and a, b, e each represent a number between 0 ≦ a <0.5,0 ≦ b <0.5,0 <e <1.0.] A vacuum vessel, an evaporation source provided in the vacuum vessel for depositing a stimulable phosphor on a support, and supporting the support and rotating the evaporation source from the evaporation source. The manufacturing method of the radiation image conversion panel which manufactures the radiation image conversion panel as described in any one of Claims 1-8 using the vapor deposition apparatus provided with the support body rotation mechanism which vapor-deposits a stimulable fluorescent substance. Because
The stimulable phosphor layer evaporating from the evaporation source is deposited on the support by supporting and rotating the support by the support rotating mechanism to form a stimulable phosphor layer. A method for producing a radiation image conversion panel.

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