X-ray shielding material, x-ray inspection device incorporating the same, and method of manufacturing x-ray shielding material

Abstract

To provide an x-ray shielding material that offers better heat dissipation efficiency compared to conventional products and can eventually contribute to miniaturization of x-ray inspection devices and manufacturing cost reduction, and to provide an x-ray inspection device incorporating the same and a method of manufacturing the x-ray shielding material.SOLUTION: An x-ray shielding material 20 provided herein is used in x-ray inspection devices to shield x-rays, and consists of a sintered body 30 comprising a metal binder 21 made of a metal having a higher heat conductivity than lead and metal powder 22 of a metal that offers given x-ray shielding performance.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an X-ray shielding material, an X-ray inspection device, and a method for manufacturing an X-ray shielding material. [Background technology]

[0002] X-ray inspection equipment is prone to temperature rise because it contains devices that generate heat, such as an X-ray generator and a computing device. On the other hand, X-ray inspection equipment is provided with a shielding member that blocks unnecessary X-rays to prevent X-ray leakage, and lead is often used as the shielding member.

[0003] However, because lead has a low thermal conductivity, it is difficult to dissipate heat from shielding materials that contain lead, so X-ray inspection equipment is equipped with a cooling unit such as a radiator or air conditioner.

[0004] For example, Patent Document 1 discloses an X-ray generator that has an electric fan for circulating insulating oil inside the tube container, heat dissipation fins on the outer surface of the tube container, and a fan for cooling the fins, so that the heat generated in the X-ray tube can be dissipated to the outside efficiently with a simple configuration. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-25792 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in an X-ray generating device or an X-ray inspection device equipped with a cooling unit as described in Patent Document 1, the installation of the cooling unit increases the size of the device and increases the manufacturing costs.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an X-ray shielding material that can improve heat dissipation efficiency compared to conventional materials, and can thereby contribute to miniaturizing X-ray inspection equipment and reducing manufacturing costs, an X-ray inspection equipment including the same, and a method for manufacturing the X-ray shielding material. [Means for solving the problem]

[0008] The X-ray shielding material of the present invention is used in an X-ray inspection device and shields X-rays, and is composed of a sintered body containing a metal binder made of a metal having a higher thermal conductivity than lead and a metal powder of a metal having a predetermined shielding performance against X-rays.

[0009] With this configuration, the X-ray shielding material according to the present invention is composed of a sintered body containing a metal binder made of a metal having a higher thermal conductivity than lead and a metal powder of a metal having a predetermined shielding performance against X-rays, so that the heat dissipation efficiency can be improved compared to a conventional X-ray shielding material formed only of lead, for example. Therefore, in an X-ray inspection device using the X-ray shielding material according to the present invention, a cooling unit can be omitted or simplified. Therefore, the X-ray shielding material according to the present invention can contribute to the miniaturization and reduction of manufacturing costs of the X-ray inspection device.

[0010] In the X-ray shielding material according to the present invention, it is preferable that the metal binder is made of at least one metal having an atomic number of 13 or more and having a thermal conductivity higher than that of lead, and the metal powder is made of at least one metal having an atomic number of 56 or more.

[0011] With this configuration, in the X-ray shielding material according to the present invention, the metal binder is made of at least one metal having a higher thermal conductivity than lead among metals having an atomic number of 13 or more, and the metal powder is made of at least one metal having an atomic number of 56 or more. Therefore, a metal having a higher thermal conductivity than lead can be used as the metal binder, and a metal with a high specific gravity can be used as the metal powder.

[0012] In the X-ray shielding material according to the present invention, it is preferable that the metal binder is made of any one of silver, copper, and aluminum, and the metal powder is made of tungsten.

[0013] With this configuration, in the X-ray shielding material according to the present invention, the metal binder is made of any one of silver, copper, and aluminum, and the metal powder is made of tungsten, so that it is harmless to the human body and can further improve heat dissipation efficiency while maintaining favorable shielding performance.

[0014] The X-ray inspection device according to the present invention includes an X-ray generator that generates X-rays, an X-ray detector that detects the X-rays, and a shielding member that blocks the X-rays, and has a configuration in which an X-ray shielding material according to any one of claims 1 to 4 is used as the shielding member.

[0015] With this configuration, the X-ray inspection device of the present invention uses the X-ray shielding material according to any one of claims 1 to 4 as a shielding member for shielding X-rays generated by an X-ray generator, so that the cooling unit can be omitted or simplified, thereby enabling miniaturization and reduction in manufacturing costs.

[0016] The manufacturing method of the X-ray shielding material according to the present invention is a manufacturing method of an X-ray shielding material that shields X-rays, and includes a sintering step of sintering metal powder of a metal having a predetermined shielding performance against X-rays, using a metal having a higher thermal conductivity than lead as a metal binder, to obtain a sintered body.

[0017] According to the manufacturing method of the X-ray shielding material of the present invention, it is possible to manufacture an X-ray shielding material having improved heat dissipation efficiency compared to a conventional X-ray shielding material formed, for example, only from lead.

[0018] In the manufacturing method of the X-ray shielding material according to the present invention, it is preferable that at least one metal having an atomic number of 13 or more and having a thermal conductivity higher than that of lead is used as the metal binder, and at least one metal having an atomic number of 56 or more is used as the metal powder.

[0019] According to the manufacturing method of the X-ray shielding material of the present invention, a metal having a higher thermal conductivity than lead can be used as the metal binder, and a metal having a large specific gravity can be used as the metal powder.

[0020] In the method for producing an X-ray shielding material according to the present invention, it is preferable that the metal binder is any one of silver, copper, and aluminum, and the metal powder is tungsten.

[0021] According to the manufacturing method of the X-ray shielding material of the present invention, it is possible to manufacture an X-ray shielding material that is harmless to the human body and can further improve heat dissipation efficiency while maintaining suitable shielding performance. Effect of the Invention

[0022] According to the present invention, it is possible to provide an X-ray shielding material that can improve heat dissipation efficiency compared to conventional methods, and thus contribute to miniaturization and reduction in manufacturing costs of X-ray inspection equipment, an X-ray inspection equipment including the same, and a manufacturing method for the X-ray shielding material. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of an X-ray inspection device equipped with an X-ray shielding material according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the X-ray shielding material according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a diagram showing a first modified example of an X-ray inspection apparatus including an X-ray shielding material according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing a second modified example of an X-ray inspection apparatus including an X-ray shielding material according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an X-ray shielding material according to one embodiment of the present invention and an X-ray inspection device in which the X-ray shielding material is used will be described with reference to the drawings.

[0025] (X-ray inspection equipment) As shown in FIG. 1, the X-ray inspection device 1 of this embodiment is incorporated, for example, in a part of a conveying line, and irradiates X-rays to the inspection objects W that are conveyed sequentially from the upstream side, and performs various inspections such as checking for the presence of foreign matter, defective sealing, and missing parts based on the amount of X-rays that pass through the inspection objects W at that time, and then conveys them downstream.

[0026] The X-ray inspection device 1 of the present embodiment is an example of an X-ray inspection device in which the X-ray shielding material according to the present invention is used, and is not limited thereto. That is, the X-ray shielding material according to the present invention is generally applicable to a wide variety of X-ray inspection devices that differ according to the X-ray irradiation method and the type of the object to be inspected.

[0027] As shown in FIG. 1, an X-ray inspection apparatus 1 of the present embodiment includes a transport unit 2, a housing 3, an X-ray generator 4, an X-ray detector 5, and a control unit 6.

[0028] The transport unit 2 is composed of, for example, a belt conveyor arranged horizontally relative to the main body of the apparatus, and transports an inspection target W on a transport path.

[0029] The transport unit 2 includes a transport belt 2a made of a material (elements other than elements with large atomic weights) that easily transmits X-rays, and drives the transport belt 2a at a transport speed set in advance by the rotation of a drive motor under the control of a transport control unit (not shown) when inspecting the inspection object W. As a result, the inspection object W carried in from the carry-in entrance is transported in the transport direction (direction indicated by the arrow) toward the carry-out exit.

[0030] The housing 3 houses therein an X-ray irradiation unit provided above the transport path of the inspection object W, specifically, an X-ray generator 4, a collimator 10, and the like.

[0031] An irradiation opening window 3 a for irradiating X-rays from the X-ray generator 4 toward the X-ray detector 5 is formed on the bottom surface of the housing 3 .

[0032] In the X-ray inspection apparatus 1 of this embodiment, curtain-like shielding curtains 3c may be provided at the entrance and exit sides of the lower part of the housing 3 as necessary to reliably prevent leakage of X-rays to the outside.

[0033] The X-ray generator 4 irradiates X-rays onto the object to be inspected W being transported on the transport path in the transport direction from the entrance to the exit, and generates X-rays by causing electrons that have been accelerated by applying a voltage to collide with a target.

[0034] The X-ray generator 4 has a configuration in which a cylindrical X-ray tube 4b is provided inside a metallic box 4a having a substantially rectangular parallelepiped shape and is immersed in insulating oil.

[0035] In the X-ray tube 4b, a cathode 4c and an anode target 4e supported by a support 4d are disposed facing each other at a predetermined distance, and an electron beam from the cathode 4c is irradiated onto the anode target 4e to generate X-rays.

[0036] X-rays generated by an anode target 4e serving as an X-ray generation source are irradiated in a screen shape toward the X-ray detector 5 through an exit window 4f and a collimator 10.

[0037] The X-ray detector 5 is provided in a housing 5a that is provided below the transport surface of the object W to face the housing 3 at a predetermined distance in the height direction.

[0038] The X-ray detector 5 includes a photodiode (not shown) and a plurality of X-ray detection elements (not shown) each made of a scintillator provided on the photodiode. As the X-ray detector 5, for example, an area sensor in which X-ray detection elements are arranged in a plane in the conveying direction and in a direction perpendicular to the conveying direction, or a line sensor in which X-ray detection elements are arranged in a line in a direction perpendicular to the conveying direction can be used.

[0039] The X-ray detector 5 converts the X-rays irradiated from the X-ray generator 4 to the object W to be inspected and transmitted through the object W into an optical signal using a scintillator, and then converts the optical signal into an electrical signal using a photodiode to output it as X-ray transmission data.

[0040] The control unit 6 stores the X-ray transmission data input from the X-ray detector 5, and performs various inspections of the inspection target W based on the X-ray transmission data, such as checking for the presence of foreign matter, defective sealing, and missing parts.

[0041] A touch panel display (not shown), in which a display unit and a setting operation unit are integrated, for example, is connected to the control unit 6. The touch panel display is configured to display various information such as the inspection results of the inspection object W and setting information.

[0042] (X-ray shielding material) In the X-ray inspection apparatus 1 of this embodiment, in order to prevent leakage of X-rays in an amount exceeding the leakage standard amount, a shielding member that blocks X-rays is used in each part or each part that constitutes the X-ray inspection apparatus 1.

[0043] For example, the shielding member is used in a member constituting the box body 4a of the X-ray generator 4, a member constituting the housing 3, etc. In addition, the shielding member may be used to line the inside of the box body 4a or the housing 3.

[0044] In the X-ray inspection device 1 of this embodiment, as the above-mentioned shielding member, an X-ray shielding material 20 as shown in Fig. 2 is used. Fig. 2 shows a cross section in a direction perpendicular to a plane (for example, a surface facing the X-ray tube 4b) of a plate-like member constituting, for example, the box body 4a of the X-ray generator 4 when the X-ray shielding material 20 is used for the plate-like member.

[0045] 2, the X-ray shielding material 20 is composed of a sintered body 30 containing a metal binder 21 made of a metal having a higher thermal conductivity than lead, and a metal powder 22 of a metal having a predetermined shielding performance against X-rays generated by an X-ray generator 4. The predetermined shielding performance means, for example, a shielding performance required to prevent leakage of X-rays in an amount exceeding a leakage reference amount in an X-ray shielding material 20 of a predetermined dimension.

[0046] The sintered body 30 is produced by sintering a metal powder 22 using a metal binder 21 as a binder in a production method described below.

[0047] As the metal binder 21, a metal with an atomic number of 13 or more can be used, for example, any one of aluminum, titanium, iron, nickel, copper, zinc, silver, tin, barium, and bismuth can be used. Furthermore, in this embodiment, it is preferable to use, as the metal binder 21, a metal with a higher thermal conductivity than lead among metals with an atomic number of 13 or more. More preferably, it is made of any one of silver, copper, and aluminum, and among these, copper is the most preferable. Copper is preferable as the metal binder 21 because it can achieve the desired thermal conductivity while being relatively inexpensive.

[0048] The metal binder 21 may be composed of a compound containing a metal with an atomic number of 13 or more, and in this case, it is preferable that the compound contains aluminum, titanium, iron, nickel, copper, zinc, silver, tin, barium, or bismuth. It is more preferable that the metal constituting the compound contains at least one of silver, copper, and aluminum.

[0049] The metal powder 22 is preferably made of a metal having an atomic number of 56 or more, and more preferably made of tungsten. The metal powder 22 may be made of a compound containing a metal having an atomic number of 56 or more, and in this case, it is preferable that the metal constituting the compound contains tungsten.

[0050] The X-ray shielding material 20 thus configured is formed by sintering the tungsten metal powder 22, which has high density and specific gravity, with the metal binder 21 as a binder, so that the X-rays incident on the X-ray shielding material 20 are attenuated or blocked by the tungsten metal powder 22, thereby preventing the X-rays from passing through. The metal binder 21 constituting the X-ray shielding material 20 is made of any one of silver, copper, and aluminum, and these metals have smaller atomic numbers than the metal powder 22, so that secondary X-rays generated inside can be suppressed.

[0051] That is, the X-rays incident on the X-ray shielding material 20 are attenuated or shielded by the tungsten remaining as powder in the sintered body 30, and further, secondary X-rays generated in one tungsten metal powder 22 are also attenuated or shielded by another tungsten metal powder 22. In addition, secondary X-rays themselves generated inside the X-ray shielding material 20 are reduced by the metal binder 21 made of any one of silver, copper, and aluminum in the sintered body 30. As a result, the X-rays incident from one surface (upper surface in FIG. 2) of the X-ray shielding material 20 are sufficiently attenuated or shielded while passing through the inside of the X-ray shielding material 20, and their energy is greatly attenuated when they penetrate the other surface (lower surface in FIG. 2) of the X-ray shielding material 20.

[0052] In this way, the X-ray shielding material 20 of the present embodiment has the same shielding performance as a shielding material formed only from a metal having a large atomic number such as tungsten, even though it is formed by sintering the tungsten metal powder 22. Furthermore, the X-ray shielding material 20 of the present embodiment is lighter in weight than a shielding material formed only from a metal having a large atomic number such as tungsten.

[0053] Furthermore, since the X-ray shielding material 20 of this embodiment uses a metal having a higher thermal conductivity than lead as the metal binder 21, heat inside the device, which is a high-temperature atmosphere, is quickly conducted from one surface (upper surface in FIG. 2) of the X-ray shielding material 20 to the outside of the device, which is the other surface (lower surface in FIG. 2) of the X-ray shielding material 20, via the metal binder 21 having high thermal conductivity. As a result, heat inside the device, which is a high-temperature atmosphere, is efficiently dissipated to the outside of the device by the metal binder 21.

[0054] (Manufacturing method of X-ray shielding material) Next, a method for manufacturing the X-ray shielding material 20 of this embodiment will be described.

[0055] The X-ray shielding material 20 of this embodiment is manufactured by the following process, including a sintering process in which a metal binder 21 made of a metal having a higher thermal conductivity than lead is used to sinter metal powder 22 of a metal having a predetermined shielding performance against X-rays generated by the X-ray generator 4 to obtain a sintered body 30.

[0056] <Mixing and grinding process> First, the metal powder 22 and the metal binder 21, which are the main materials of the X-ray shielding material 20, are finely pulverized or mixed to a desired ratio between the metal powder 22 and the metal binder 21. In order to improve the sinterability, a sintering aid may be added to the metal powder 22 and the metal binder 21 within a range that does not affect the material properties.

[0057] <Forming process> In the molding step, the metal powder 22 and the metal binder 21 mixed in the mixing and pulverizing step are put into a mold having the shape of the shielding member of the X-ray inspection device 1, and compressed and molded by a press. At this time, an organic substance such as wax may be added as a molding assistant.

[0058] <Sintering process> In the sintering process, the compact formed in the above molding process is heated and baked in a sintering furnace for a predetermined time at a temperature lower than the melting points of the metal powder 22 and the metal binder 21. As a result, the powder metals are bonded by a diffusion phenomenon, and the sintered body 30 is completed.

[0059] <Machining process> The sintered body 30 obtained in the above sintering step may be subjected to mechanical processing such as grinding and polishing, or may be subjected to a heat treatment for increasing hardness, if necessary.

[0060] (Action and effect) As described above, the X-ray shielding material according to this embodiment is composed of the sintered body 30 including the metal binder 21 made of a metal having a higher thermal conductivity than lead and the metal powder 22 made of a metal having a predetermined shielding performance against the X-rays generated by the X-ray generator 4, and therefore the heat dissipation efficiency can be improved compared to a conventional X-ray shielding material formed only of lead, for example. Therefore, in the X-ray inspection device 1 using the X-ray shielding material according to this embodiment, the cooling unit can be omitted or simplified. Therefore, the X-ray shielding material according to this embodiment can contribute to the miniaturization and manufacturing cost reduction of the X-ray inspection device 1.

[0061] In addition, in the X-ray shielding material according to this embodiment, the metal binder 21 is made of at least one metal having a higher thermal conductivity than lead among metals having an atomic number of 13 or more, and the metal powder 22 is made of at least one metal having an atomic number of 56 or more. Therefore, a metal having a higher thermal conductivity than lead can be used as the metal binder 21, and a metal having a high specific gravity can be used as the metal powder 22.

[0062] In addition, in the X-ray shielding material according to the present embodiment, the metal binder 21 is made of any one of silver, copper, and aluminum, and the metal powder 22 is made of tungsten, so that the X-ray shielding material is harmless to the human body and can further improve the heat dissipation efficiency while maintaining a suitable shielding performance.

[0063] Furthermore, since the X-ray inspection apparatus according to this embodiment uses the X-ray shielding material 20 as a shielding member for shielding the X-rays generated by the X-ray generator 4, the cooling unit can be omitted or simplified, thereby enabling miniaturization and reduced manufacturing costs.

[0064] Moreover, according to the manufacturing method of the X-ray shielding material according to the present embodiment, it is possible to manufacture the X-ray shielding material 20 having improved heat dissipation efficiency compared to a conventional X-ray shielding material formed, for example, only from lead.

[0065] (First Modification) The X-ray shielding material according to the present invention may be used as a shielding member constituting a shielding cover 31 provided above the entrance and exit of the inspection object W in an X-ray inspection apparatus 101 according to a first modified example as shown in FIG.

[0066] (Second Modification) In addition, the X-ray shielding material according to the present invention may be used as a shielding member constituting a shielding cover 32 that covers the entrance and exit of the inspection object W in an X-ray inspection apparatus 201 according to a second modified example as shown in FIG.

[0067] Furthermore, the X-ray shielding material according to the present invention can also be applied to shielding members used in X-ray inspection devices other than the X-ray inspection devices shown in the present embodiment, the first modified example, and the second modified example. For example, the X-ray shielding material according to the present invention may be used in a plate-shaped shielding gate provided at the entrance and exit of an X-ray inspection device other than those described above, and can also be applied to any other shielding member provided to prevent leakage of X-rays.

[0068] Although an embodiment of the present invention has been disclosed, it will be apparent to one of ordinary skill in the art that modifications may be made thereto without departing from the scope of the present invention, and all such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0069] 1, 101, 201 X-ray inspection equipment 2. Conveyor section 3. Chassis 4 X-ray generator 4a box body 5. X-ray detector 5a Case 6 Control section 20 X-ray shielding material (shielding component) 21 Metal Binder 22 Metal powder 30 Sintered body 31, 32 Shielding cover W Inspection item

Claims

1. An X-ray shielding material (20) used in an X-ray inspection device to shield against X-rays, comprising: The X-ray shielding material is constituted by a sintered body (30) containing a metal binder (21) made of a metal having a higher thermal conductivity than lead, and a metal powder (22) of a metal having a predetermined shielding performance against the X-rays.

2. The metal binder is made of at least one metal having an atomic number of 13 or more and having a thermal conductivity higher than that of lead, 2. The X-ray shielding material according to claim 1, wherein the metal powder is made of at least one metal having an atomic number of 56 or more.

3. the metal binder is made of any one of silver, copper, and aluminum; 2. The X-ray shielding material according to claim 1, wherein the metal powder is made of tungsten.

4. the metal binder is made of any one of silver, copper, and aluminum; 3. The X-ray shielding material according to claim 2, wherein the metal powder is made of tungsten.

5. An X-ray generator (4) for generating X-rays; An X-ray detector (5) for detecting the X-rays; A shielding member (20) that blocks the X-rays, 5. An X-ray inspection apparatus using the X-ray shielding material according to claim 1 as the shielding member.

6. A method for manufacturing an X-ray shielding material (20) for shielding X-rays, comprising the steps of: A method for producing an X-ray shielding material, comprising a sintering step of sintering a metal powder (22) of a metal having a predetermined shielding performance against X-rays, using a metal having a higher thermal conductivity than lead as a metal binder (21), to obtain a sintered body (30).

7. As the metal binder, at least one metal having an atomic number of 13 or more and having a thermal conductivity higher than that of lead is used, The method for producing an X-ray shielding material according to claim 6, wherein at least one metal having an atomic number of 56 or more is used as the metal powder.

8. The metal binder is selected from the group consisting of silver, copper, and aluminum.

8. The method for producing an X-ray shielding material according to claim 6, wherein tungsten is used as the metal powder.

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