JP2008198896A - Method for manufacturing amorphous selenium doped with alkali metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly manufacture amorphous selenium doped with an extremely fine amount of an alkali metal at high yield. <P>SOLUTION: After producing a mother selenium alloy doped with an alkaline metal of concentration higher than a prescribed concentration in a closed system, the mother selenium alloy and pure selenium alloy are mixed with each other to manufacture amorphous selenium doped with the alkaline metal of the prescribed concentration. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing amorphous selenium doped with an alkali metal, which is suitable for use in a radiation imaging panel applied to a radiation imaging apparatus such as an X-ray.

  Conventionally, in medical X-ray imaging, a photoconductive layer that is sensitive to X-rays is used as a photoconductor to reduce the exposure dose received by a subject and improve diagnostic performance. An X-ray imaging panel that reads and records a recorded electrostatic latent image with light or multiple electrodes is known. These are superior in that the resolution is higher than the indirect photographing method using a TV image pickup tube which is a well-known photographing method.

The X-ray imaging panel described above generates charges corresponding to X-ray energy by irradiating the charge generation layer provided in the imaging panel with X-rays, and reads the generated charges as an electrical signal. The photoconductive layer functions as a charge generation layer. Conventionally, materials such as amorphous selenium (a-Se), PbO, PbI ₂ , HgI ₂ , BiI ₃ , and Cd (Zn) Te are used for the photoconductive layer.

The amorphous selenium can easily cope with an increase in area by using a thin film forming technique such as a vacuum vapor deposition method, but sensitivity tends to deteriorate because it tends to include many structural defects due to amorphous. For this reason, in order to improve performance, doping with an alkali metal element is generally performed (Patent Document 1). In particular, it is known that the range of the doping amount necessary for improving the performance is as extremely small as 0.01 to 10 ppm, and the allowable range is narrow (Patent Document 2).
US Pat. No. 3,658,989 JP 2003-315464 A

  When trying to manufacture amorphous selenium doped with a trace amount of alkali metal having a narrow allowable range as described in Patent Document 2 in an unsealed system, there is a problem that the manufacturing variation is large and the yield is poor. .

  The present invention has been made in view of the above circumstances, and a method for producing amorphous selenium doped with a predetermined amount of alkali metal capable of producing amorphous selenium doped with an extremely small amount of alkali metal with high yield and uniformity. Is intended to provide.

  In the method for producing amorphous selenium according to the present invention, a mother selenium alloy doped with an alkali metal at a concentration higher than a predetermined concentration in a closed system is prepared, and then the mother selenium alloy and pure selenium alloy are mixed to obtain a predetermined concentration of alkali metal It is characterized by producing doped amorphous selenium.

  Here, the density higher than the predetermined density means a density of 10 times or more the predetermined density. A pure selenium alloy means a selenium alloy that does not contain an alkali metal or is below the detection limit. The closed system for producing the mother selenium alloy means that the raw material selenium and the alkali metal can be sealed and the environment is free from moisture and oxygen.

  After the mother selenium alloy is produced, the mother selenium alloy and the pure selenium alloy may be mixed in a closed system or a non-sealed system.

  After producing the mother selenium alloy, it is preferable to analyze the alkali metal concentration of the mother selenium alloy and determine the mixing ratio of the mother selenium alloy and pure selenium alloy based on the analysis result.

  The step of manufacturing amorphous selenium mixed with a predetermined concentration of alkali metal by mixing the mother selenium alloy and pure selenium alloy is preferably performed by shotting or by manufacturing a chunk.

  The alkali metal concentration of the mother selenium alloy is preferably 50 ppm to 300 ppm by weight.

  The method for producing amorphous selenium doped with a predetermined concentration of alkali metal according to the present invention comprises preparing a mother selenium alloy doped with an alkali metal at a concentration higher than a predetermined concentration in a closed system, and then mixing the mother selenium alloy and pure selenium alloy. As a result, amorphous selenium doped with a predetermined concentration of alkali metal is produced, so that amorphous selenium doped with a very small amount of alkali metal is initially produced in a non-sealed system. Can be manufactured with high yield.

  When the amorphous selenium doped with a trace amount of alkali metal produced in this way is applied to the photoconductive layer of the radiation imaging panel, local crystallization is less likely to occur, and the electron transit is improved. It is possible to suppress an increase in image defects due to local crystallization progress.

  The method for producing amorphous selenium according to the present invention is characterized in that a mother selenium alloy doped with an alkali metal having a concentration higher than a predetermined concentration is produced in a closed system, and then the mother selenium alloy and pure selenium alloy are mixed.

  The closed system for producing the parent selenium alloy is an environment in which selenium and alkali metal as raw materials can be sealed as described above, and in a state where moisture and oxygen do not enter, and preferably is sealed in a quartz tube or the like It is desirable that In order to prevent the quartz tube from bursting when the temperature is raised for mixing, it is desirable to reduce the pressure to 0.5 atm or less.

The alkali metal is Na, Li, K, Rb, Sc, and the amorphous selenium doped with the mother selenium alloy and the final alkali metal at a predetermined concentration is Na ₂ Se, Li ₂ Se, K ₂ Se, Rb ₂ Se, Sc ₂ Se. The alkali metal concentration of the mother selenium alloy is 10 times or more higher than the predetermined concentration, and preferably 50 ppm to 300 ppm by weight. When the concentration is higher than 300 ppm by weight, the alkali metal is likely to precipitate. When the concentration is lower than 50 ppm by weight, it is necessary to increase the production amount of the master alloy, which is not economical. After producing the mother selenium alloy, an alkali metal concentration analysis of the mother selenium alloy is performed, and the mixing ratio of the mother selenium alloy and the pure selenium alloy is determined based on the analysis result.

  The step of producing amorphous selenium mixed with a predetermined concentration of alkali metal by mixing mother selenium alloy and pure selenium alloy is preferably performed by shotting or by producing chunks. Shotting is a process in which mother selenium alloy and pure selenium alloy are mixed to form a solution, stirred, and then extruded into a granule by extruding the solution from a nozzle with a small hole of about 0.5 to 3 mm in air or nitrogen gas. A chunk is a manufacturing method in which a mother selenium alloy and a pure selenium alloy are mixed to form a solution and then cooled as it is to form a solid state.

The radiation imaging panel includes a direct conversion system that directly converts radiation into electric charge and accumulates the charge, and once converts the radiation into light by a scintillator such as CsI: Tl, Gd ₂ O ₂ S: Tb, and the light is a− Although there is an indirect conversion method in which charges are converted and stored by a Si photodiode, amorphous selenium manufactured by the manufacturing method of the present invention is used for the former direct conversion method as well as an indirect conversion type photoelectric conversion layer. be able to. In addition to X-rays, γ rays, α rays, etc. can be used as radiation.

  Amorphous selenium produced by the production method of the present invention is also generated by irradiation of radiation in a so-called optical reading method in which reading is performed by a radiation image detector using a semiconductor material that generates a charge by irradiation of light. It can also be used in a method of accumulating charges and reading the accumulated charges by turning on and off an electrical switch such as a thin film transistor (TFT) one pixel at a time (hereinafter referred to as TFT method).

  First, a radiation imaging panel used for the former optical reading method will be described as an example. FIG. 1 is a cross-sectional view showing an embodiment of a radiation imaging panel using amorphous selenium produced by the production method of the present invention as a photoconductive layer.

  The radiation imaging panel 10 includes a first conductive layer 1 that is transparent to a recording radiation L1, which will be described later, and a recording radiation that exhibits conductivity when irradiated with the radiation L1 transmitted through the conductive layer 1. The conductive layer 2 and the charge charged on the conductive layer 1 (latent image polar charge; for example, negative charge) act as an insulator and have a charge opposite to the charge (transport polar charge; in the above example) Is positively charged), a charge transport layer 3 that acts as a substantially conductive material, a read photoconductive layer 4 that exhibits conductivity when irradiated with read light L2 for reading, which will be described later, and is transparent to electromagnetic waves L2. The second conductive layer 5 having the above is laminated in this order.

Here, as the conductive layers 1 and 5, for example, a transparent glass plate uniformly coated with a conductive material (nesa film or the like), more specifically, polycrystalline ITO (In ₂ O ₃ : Sn) ), Amorphous ITO (In ₂ O ₃ : Sn), amorphous IZO (In ₂ O ₃ : Zn), ATO (SnO ₂ : Sb), FTO (SnO ₂ : F), AZO (ZnO: Al), GZO (ZnO) : Ga), a thin film of gold, silver, platinum, aluminum, indium or the like, or a coating film of a dispersion of a noble metal (platinum, gold, silver) having a size of about 10 to 1000 nm.

As the charge transport layer 3, the larger the difference between the mobility of the negative charge charged in the conductive layer 1 and the mobility of the positive charge having the opposite polarity, the better, poly N-vinylcarbazole (PVK), N, N Organic compounds such as' -diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine (TPD) and discotic liquid crystals, or TPD polymers ( Polycarbonate, polystyrene, PVK, polyvinyl alcohol) dispersion, As ₂ Se ₃ , Sb ₂ S ₃ , silicon oil, semiconductor materials such as a-Se doped with 10 to 200 ppm of Cl, and polycarbonate are suitable. In particular, an organic compound (PVK, TPD, discotic liquid crystal, etc.) is preferable because it has light insensitivity, and since the dielectric constant is generally small, the capacitance of the charge transport layer 3 and the reading photoconductive layer 4 is reduced. The signal extraction efficiency can be increased.

The reading photoconductive layer 4 includes a-Se, Se-Te, Se-As-Te, As ₂ Se ₃ , metal-free phthalocyanine, metal phthalocyanine, MgPc (Magnesium phtalocyanine) doped with 10-200 ppm of a-Se, Cl. , VoPc (phase II of Vanadyl phthalocyanine), CuPc (Cupper phtalocyanine), Bi ₁₂ MO ₂₀ (M: Ti, Si, Ge), Bi ₄ M ₃ O ₁₂ (M: Ti, Si, Ge), Bi ₂ O ₃ , BiMO ₄ (M: Nb, Ta, V), Bi ₂ WO ₆ , Bi ₂₄ B ₂ O ₃₉ , ZnO, ZnS, ZnSe, ZnTe, MNbO ₃ (M: Li, Na, K), PbO, HgI ₂ , PbI ₂ , a photoconductive substance containing at least one of CdS, CdSe, CdTe, BiI _{3 and the} like as a main component is preferable.

  For the recording radiation conductive layer 2, amorphous selenium produced by the production method of the present invention is used. That is, the amorphous selenium produced by the production method of the present invention is a recording radiation conductive layer.

  An electron injection blocking layer may be provided between the first conductive layer and the recording radiation conductive layer 2. As the electron injection blocking layer, antimony sulfide, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD) is used. It is done. Further, a hole injection blocking layer may be provided between the reading photoconductive layer 4 and the second conductive layer 5. As the hole injection blocking layer, cerium oxide, antimony sulfide, and zinc sulfide are used.

  Next, a system that uses light to read an electrostatic latent image will be briefly described. FIG. 2 is a schematic configuration diagram of a recording / reading system using the radiation imaging panel 10 (integrated electrostatic latent image recording device and electrostatic latent image reading device). This recording / reading system comprises a radiation imaging panel 10, a recording irradiation means 90, a power source 50, a current detection means 70, a reading exposure means 92, and connection means S1, S2. The panel 10, the power supply 50, the recording irradiation means 90, and the connection means S 1, and the electrostatic latent image reading device portion includes the radiation imaging panel 10, the current detection means 70, and the connection means S 2.

  The conductive layer 1 of the radiation imaging panel 10 is connected to the negative electrode of the power source 50 through the connection means S1, and is also connected to one end of the connection means S2. One end of the connection means S2 is connected to the current detection means 70, and the conductive layer 5 of the radiation imaging panel 10, the positive electrode of the power supply 50, and the other end of the connection means S2 are grounded. The current detection means 70 includes a detection amplifier 70a made of an operational amplifier and a feedback resistor 70b, and constitutes a so-called current-voltage conversion circuit.

  The conductive layer 5 may have a structure described in Japanese Patent Application Laid-Open Nos. 2001-337171 and 2001-160922.

  A subject 9 is disposed on the upper surface of the conductive layer 1, and the subject 9 has a portion 9a that is transparent to the radiation L1 and a blocking portion 9b that is not transparent. The recording irradiation means 90 uniformly exposes the radiation L1 to the subject 9, and the reading exposure means 92 emits the reading light L2 such as laser light, LED, organic EL, inorganic EL, etc. in the direction of the arrow in FIG. It is desirable that the reading light L2 has a linearly converged shape.

  The electrostatic latent image recording process in the recording / reading system configured as described above will be described below with reference to a charge model (FIG. 3). In FIG. 2, the connection means S2 is opened (not connected to either the ground or current detection means 70), the connection means S1 is turned on, and the DC voltage Ed from the power source 50 is applied between the conductive layer 1 and the conductive layer 5. Then, a negative charge is applied to the conductive layer 1 and a positive charge is applied to the conductive layer 5 from the power source 50 (see FIG. 3A). Thereby, a parallel electric field is formed between the conductive layers 1 and 5 in the radiation imaging panel 10.

  Next, the radiation L1 is uniformly irradiated toward the subject 9 from the recording irradiation means 90. The radiation L1 passes through the transmission part 9a of the subject 9, and further passes through the conductive layer 1. The radiation conductive layer 2 receives the transmitted radiation L1 and exhibits conductivity. This is understood by acting as a variable resistor that shows a variable resistance value according to the dose of radiation L1, and the resistance value is caused by the generation of a charge pair of electrons (negative charge) and holes (positive charge) by radiation L1. The resistance value is large if the dose of the radiation L1 transmitted through the subject 9 is small (see FIG. 3B). The negative charge (−) and the positive charge (+) generated by the radiation L1 are represented by enclosing − or + in circles in the drawing.

  The positive charge generated in the radiation conductive layer 2 moves at high speed in the radiation conductive layer 2 toward the conductive layer 1, and the negative charge is charged in the conductive layer 1 at the interface between the conductive layer 1 and the radiation conductive layer 2. And disappear due to charge recombination (see FIGS. 3C and 3D). On the other hand, the negative charges generated in the radiation conductive layer 2 move in the radiation conductive layer 2 toward the charge transport layer 3. Since the charge transport layer 3 acts as an insulator against a charge having the same polarity as the charge charged on the conductive layer 1 (in this example, a negative charge), the negative charge moving through the radiation conductive layer 2 is radiation. It stops at the interface between the conductive layer 2 and the charge transport layer 3 and accumulates at this interface (see FIGS. 3C and 3D). The amount of charge accumulated is determined by the amount of negative charge generated in the radiation conductive layer 2, that is, the dose of radiation L1 transmitted through the subject 9.

  On the other hand, since the radiation L1 does not pass through the blocking portion 9b of the subject 9, no change occurs in the portion corresponding to the lower portion of the blocking portion 9b of the radiation imaging panel 10 (see FIGS. 3B to 3D). In this way, by exposing the subject 9 to the radiation L1, charges corresponding to the subject image can be accumulated at the interface between the radiation conductive layer 2 and the charge transport layer 3. The subject image based on the accumulated charges is called an electrostatic latent image.

  Next, an electrostatic latent image reading process will be described with reference to a charge model (FIG. 4). The connection means S1 is opened to stop the power supply, and S2 is temporarily connected to the ground side, and the conductive layers 1 and 5 of the radiation imaging panel 10 on which the electrostatic latent image is recorded are charged to the same potential to recharge the charge. After the arrangement (see FIG. 4A), the connection means S2 is connected to the current detection means 70 side.

  When the reading light L2 is scanned and exposed to the conductive layer 5 side of the radiation imaging panel 10 by the reading exposure means 92, the reading light L2 passes through the conductive layer 5, and the photoconductive layer 4 irradiated with the transmitted reading light L2 is Conductivity is exhibited according to scanning exposure. This is dependent on the fact that the radiation conductive layer 2 is irradiated with the radiation L1 to generate positive and negative charge pairs, and has a positive and negative charge pair upon irradiation with the reading light L2. (See FIG. 4B). As in the recording process, negative charges (−) and positive charges (+) generated by the reading light L2 are represented by enclosing − or + in circles in the drawing.

  Since the charge transport layer 3 acts as a conductor for positive charges, the positive charge generated in the photoconductive layer 4 rapidly moves in the charge transport layer 3 so as to be attracted to the accumulated charges, The accumulated charges recombine and disappear at the interface between the radiation conductive layer 2 and the charge transport layer 3 (see FIG. 4C). On the other hand, the negative charge generated in the photoconductive layer 4 is recombined with the positive charge of the conductive layer 5 and disappears (see FIG. 4C). The photoconductive layer 4 is scanned and exposed with a sufficient amount of light by the reading light L2, and the accumulated charges accumulated at the interface between the radiation conductive layer 2 and the charge transport layer 3, that is, the electrostatic latent image are all recombined. Will be extinguished. Thus, the disappearance of the charges accumulated in the radiation imaging panel 10 means that the current I has flowed through the radiation imaging panel 10 due to the movement of charges, and this state is the radiation imaging panel 10. Can be expressed by an equivalent circuit as shown in FIG. 4D, in which the current amount is expressed by a current source whose amount depends on the accumulated charge amount.

  In this way, by detecting the current flowing out from the radiation imaging panel 10 while scanning and exposing the reading light L2, it is possible to sequentially read the accumulated charge amount of each scanning-exposed part (corresponding to the pixel). The electrostatic latent image can be read. The operation of the radiation detection unit is described in Japanese Patent Application Laid-Open No. 2000-105297.

  Next, the latter TFT type radiation imaging panel will be described. This radiation imaging panel has a structure in which a radiation detection unit 100 and an active matrix array substrate (hereinafter referred to as an AMA substrate) 200 are joined as shown in FIG. As shown in FIG. 6, the radiation detection unit 100 is roughly divided into a common electrode 103 for applying a bias voltage and light that generates carriers that are electron-hole pairs in response to the radiation to be detected in order from the radiation incident side. The conductive layer 104 and the detection electrode 107 for collecting carriers are stacked. The upper layer of the common electrode may have a radiation detection unit support.

  The photoconductive layer 104 is amorphous selenium manufactured by the manufacturing method of the present invention. The common electrode 103 and the detection electrode 107 are made of a conductive material such as ITO (indium tin oxide), Au, or Pt, for example. Depending on the polarity of the bias voltage, a hole injection blocking layer and an electron injection blocking layer may be attached to the common electrode 103 and the detection electrode 107. As the hole injection blocking layer, cerium oxide, antimony sulfide, zinc sulfide, and as the electron injection blocking layer, antimony sulfide, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1, 1'-biphenyl] -4,4'-diamine (TPD) is used.

  The configuration of each part of the AMA substrate 200 will be briefly described. As shown in FIG. 7, the AMA substrate 200 is provided with a capacitor 210 as a charge storage capacitor and a TFT 220 as a switching element for each of the radiation detection portions 105 corresponding to pixels. In the support 102, the radiation detection units 105 corresponding to the pixels are two-dimensionally arranged in a matrix configuration of about 1000 to 3000 × 1000 to 3000 in accordance with the required pixels, and the AMA substrate 200 also has pixels. The same number of capacitors 210 and TFTs 220 are two-dimensionally arranged in the same matrix configuration. The electric charge generated in the photoconductive layer is accumulated in the capacitor 210 and becomes an electrostatic latent image corresponding to the optical reading method. In the TFT method, an electrostatic latent image generated by radiation is held in a charge storage capacitor.

  Specific configurations of the capacitor 210 and the TFT 220 in the AMA substrate 200 are as shown in FIG. That is, the AMA substrate support 230 is an insulator, and the connection-side electrode 210b of the capacitor 210 and the TFT 220 are disposed on the ground electrode 210a of the capacitor 210 and the gate electrode 220a of the TFT 220 formed on the surface thereof via the insulating film 240. In addition to the source electrode 220b and the drain electrode 220c being stacked, the outermost surface side is covered with a protective insulating film 250. Further, the connection side electrode 210b and the source electrode 220b are connected to each other and are formed simultaneously. As the insulating film 240 constituting both the capacitor insulating film of the capacitor 210 and the gate insulating film of the TFT 220, for example, a plasma SiN film is used. The AMA substrate 200 is manufactured by using a thin film forming technique or a fine processing technique used for manufacturing a liquid crystal display substrate.

  Subsequently, the joining of the radiation detection unit 100 and the AMA substrate 200 will be described. With the detection electrode 107 and the connection side electrode 210b of the capacitor 210 aligned, both substrates 100 and 200 are made of anisotropic conductive film (ACF) containing conductive particles such as silver particles and having conductivity only in the thickness direction. The substrates 100 and 200 are mechanically combined by heating and pressurizing and bonding together, and at the same time, the detection electrode 107 and the connection side electrode 210b are electrically connected by the interposition conductor 140. .

  Further, the AMA substrate 200 is provided with a read drive circuit 260 and a gate drive circuit 270. As shown in FIG. 7, the read drive circuit 260 is connected to a read wiring (read address line) 280 in the vertical (Y) direction that connects the drain electrodes of the TFTs 220 having the same column, and the gate drive circuit 270 has a row. A horizontal (X) direction read line (gate address line) 290 connecting the gate electrodes of the same TFT 220 is connected. Although not shown, one preamplifier (charge-voltage converter) is connected to one readout wiring 280 in the readout drive circuit 260. As described above, the read driving circuit 260 and the gate driving circuit 270 are connected to the AMA substrate 200. However, an integrated circuit in which the read drive circuit 260 and the gate drive circuit 270 are integrally formed in the AMA substrate 200 is also used.

The radiation detection operation by the radiation imaging apparatus in which the radiation detector 100 and the AMA substrate 200 are joined and combined is described in, for example, Japanese Patent Application Laid-Open No. 11-287862.
Examples of the production method of the present invention are shown below.

(Examples 1-3)
A total of 500 g of Na ₂ Se and 6N high-purity selenium was placed in a quartz tube having an inner diameter of 3 cm, sealed in a vacuum of 10 ⁻⁵ Pa or less, and heat-treated at 500 ° C. for 4 hours in a rocking furnace and mixed. When Na concentration analysis of the obtained Na-doped Se was performed, a mother selenium alloy doped with 75 ppm by weight of Na was obtained. This mother selenium alloy and 6N high-purity selenium are mixed to a Na concentration of 15, 7.5, and 3.8 ppm by weight, and stirred and mixed in a closed furnace at 350 ° C. for 1 hour, and then chunk Na-doped Se was obtained. As a result of obtaining actual concentrations by ICP-MS method, they were 15, 7, and 4 ppm by weight, respectively.

Example 4
As in Example 1, 500 g of high-purity selenium of Na ₂ Se and 6N was put in a quartz tube with an inner diameter of 3 cm and sealed at a vacuum of 10 ⁻⁵ Pa or less, and this was sealed in a rocking furnace at 500 ° C. for 4 hours. Heat treatment and mixing were performed to obtain a mother selenium alloy doped with 41 ppm by weight of Na. This mother selenium alloy and 6N high-purity selenium were mixed so as to have a Na concentration of 8 ppm by weight, and stirred and mixed in a closed furnace at 350 ° C. for 1 hour to obtain chunk Na-doped Se. The actual concentration obtained by ICP-MS method was 6.5 ppm by weight.

(Example 5)
As in Example 1, 500 g of high-purity selenium of Na ₂ Se and 6N was put in a quartz tube with an inner diameter of 3 cm and sealed at a vacuum of 10 ⁻⁵ Pa or less, and this was sealed in a rocking furnace at 500 ° C. for 4 hours. After heat treatment and mixing, a mother selenium alloy doped with 110 ppm by weight of Na was obtained. This mother selenium alloy and 6N high-purity selenium were mixed to a concentration of 15.5 ppm by weight, stirred and mixed at 350 ° C. for 1 hour in a shotting furnace, and (not sealed) Na-doped Se by shotting Got. As a result of obtaining the actual concentration by the ICP-MS method, it was 12.5 ppm by weight.

(Comparative example)
Na ₂ Se was directly placed in a furnace with high-purity selenium, stirred and mixed at 350 ° C. for 1 hour, and Na-doped Se was obtained by shotting. The sample was prepared 14 times with a feed concentration of 12 ppm by weight, and the concentration was analyzed by the ICP-MS method.

The results of Examples and Comparative Examples are shown in Tables 1 and 2. In Table 1, the charged concentration is a calculated concentration, and the actual concentration is a concentration obtained by the ICP-MS method.

  As shown in Table 1, in Examples 1 to 5 in which a mother selenium alloy having a concentration higher than a predetermined concentration was produced in a closed system, and then the mother selenium alloy and pure selenium alloy were mixed to obtain Na-doped Se, Compared with the comparative example manufactured from an unsealed system, the obtained Na-doped Se has a small deviation from the charged concentration, the distribution is suppressed, and can be manufactured with a high yield. On the other hand, in the comparative example produced from the beginning in an unsealed system, the actual concentration obtained by the ICP-MS method was distributed between 4 and 10 ppm with respect to the charged concentration of 12 ppm by weight.

Sectional drawing which shows one Embodiment of the radiation imaging panel using the amorphous selenium manufactured with the manufacturing method of this invention as a photoconductive layer Schematic configuration diagram of a recording and reading system using a radiation imaging panel Diagram showing the electrostatic latent image recording process in a recording and reading system using a charge model Diagram showing the electrostatic latent image reading process in the recording and reading system using a charge model Schematic diagram showing the combined state of the radiation detector and the AMA substrate Schematic cross-sectional view showing the pixels of the radiation detector Electrical circuit diagram showing equivalent circuit of AMA substrate

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive layer 2 Recording radiation conductive layer 3 Charge transport layer 4 Reading photoconductive layer 5 Conductive layer 10 Radiation imaging panel

Claims (5)

  After producing a mother selenium alloy doped with an alkali metal at a concentration higher than a predetermined concentration in a closed system, the mother selenium alloy and pure selenium alloy are mixed to produce amorphous selenium doped with an alkali metal at a predetermined concentration. A method for producing amorphous selenium.   The alkali metal concentration analysis of the mother selenium alloy is performed after the mother selenium alloy is manufactured, and the mixing ratio of the mother selenium alloy and the pure selenium alloy is determined based on the analysis result. A method for producing amorphous selenium according to 1.   The method for producing amorphous selenium according to claim 1 or 2, wherein the step of producing amorphous selenium mixed with a predetermined concentration of alkali metal by mixing the mother selenium alloy and pure selenium alloy is performed by shotting.   3. The amorphous selenium alloy according to claim 1, wherein the step of producing amorphous selenium mixed with the mother selenium alloy and pure selenium alloy and doped with a predetermined concentration of alkali metal is performed by producing a chunk. Production method.   The method for producing amorphous selenium according to any one of claims 1 to 4, wherein an alkali metal concentration of the parent selenium alloy is 50 ppm to 300 ppm by weight.

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