X-ray generation device and x-ray imaging device

Abstract

This X-ray generation device comprises an X-ray generation tube, a drive circuit, and a housing container. The X-ray generation tube includes: an insulation pipe having first and second open ends; a cathode closing the first open end of the insulation pipe and including an electron-emitting portion; and an anode closing the second open end and including a target with which electrons from the electron-emitting portion collide. The housing container has a third open end, which is closed by the X-ray generation tube. The housing container is filled with an insulating liquid. The housing container defines a first space in which the drive circuit is housed, and a second space that protrudes from the first space and in which at least a part of the X-ray generation tube is housed. The housing container includes a protruding portion surrounding the second space, one end of the second space constituting the third open end. A part of the outer surface of the insulation pipe is surrounded by an X-ray blocking member extending from the anode toward the cathode so as to block X-ray. The X-ray blocking member is covered by an insulation member.

Description

X-ray generator and X-ray imaging device

[0001] The present invention relates to an X-ray generating device and an X-ray imaging device.

[0002] Patent Document 1 describes an X-ray generating device including an X-ray generating tube, a tube drive circuit that drives the X-ray generating tube, and a housing container that houses the X-ray generating tube and the tube drive circuit. The housing container is filled with an insulating liquid that ensures insulation between the X-ray generating tube and the tube drive circuit.

[0003] JP 2016-103451 A

[0004] When an X-ray generating device is used for a long period of time, abnormal discharge may occur in the X-ray generating tube. Investigations by the inventors have revealed that abnormal discharge occurs between the cathode and anode of the X-ray generating tube through the outer surface of the insulating tube. The abnormal discharge may cause the X-ray generating device to stop or break down.

[0005] One aspect of the present invention provides an advantageous technique for suppressing the occurrence of abnormal discharge in an X-ray generating device.

[0006] A first aspect of the present invention relates to an X-ray generator, which may include an X-ray generating tube, a drive circuit for driving the X-ray generating tube, and a housing container for housing the X-ray generating tube and the drive circuit. The X-ray generating tube may include an insulating tube having a first open end and a second open end, a cathode arranged to close the first open end of the insulating tube and including an electron emitter, and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitter collide with the cathode. The housing container may have a third open end, and the X-ray generating tube may be arranged to close the third open end. The housing container may be filled with an insulating liquid. The housing container may define a first space for housing the drive circuit and a second space protruding from the first space for housing at least a portion of the X-ray generating tube. The housing container may include a protrusion surrounding the second space, and one end of the second space may constitute the third open end. A portion of the outer surface of the insulating tube may be surrounded by an X-ray shielding member extending from the anode toward the cathode to block X-rays. The X-ray shielding member may be covered by an insulating member.

[0007] A second aspect of the present invention relates to an X-ray imaging device, which includes the X-ray generator according to the first aspect and an X-ray detector that detects X-rays emitted from the X-ray generator.

[0008] FIG. 1 is a diagram schematically showing the configuration of a conventional X-ray generator, illustrating the basic configuration of the X-ray generator according to the present disclosure. FIG. 2 is a diagram exemplarily and schematically showing the configuration of the X-ray generator according to the first embodiment. FIG. 3 is a diagram exemplarily and schematically showing the configuration of the X-ray generator according to the second embodiment. FIG. 4 is a diagram exemplarily and schematically showing the configuration of the X-ray generator according to the third embodiment. FIG. 5 is a diagram exemplarily and schematically showing the configuration of the X-ray generator according to the fourth embodiment. FIG. 6 is a diagram exemplarily showing the occurrence of abnormal discharge. FIG. 7 is a diagram exemplifying the triboelectric series in frictional charging with an insulating liquid. FIG. 8 is a diagram explaining a problem with the X-ray generator according to the fifth embodiment. FIG. 9 is an example and schematic diagram of the configuration of the X-ray generator according to the fifth embodiment. FIG. 10 is a diagram exemplarily and schematically showing the configuration of a first modified example of the X-ray generator according to the fifth embodiment. FIG. 11 is a diagram exemplarily and schematically showing the configuration of a second modified example of the X-ray generator according to the fifth embodiment. FIG. 12 is an example and schematic diagram of the configuration of the X-ray generator according to the sixth embodiment. FIG. 13 is a diagram exemplarily and schematically showing the configuration of a modified example of the X-ray generator according to the sixth embodiment. FIG. 14 is an example and schematic diagram of the configuration of an X-ray generator according to the seventh embodiment. 13 is a diagram schematically illustrating the configuration of a modified example of the X-ray generation device according to the eighth embodiment. FIG.

[0009] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0010] First, the basic configuration of an X-ray generator 100 according to the present disclosure will be described with reference to FIG. 1 . The X-ray generator 100 may include an X-ray generating tube 1 and a housing container 50 that houses the X-ray generating tube 1. The X-ray generator 100 may further include a drive circuit 40 that drives the X-ray generating tube 1. The drive circuit 40 may be housed in the housing container 50 and connected to the X-ray generating tube 1 via a cable 42. A portion of the X-ray generating tube 1 (the anode 20, described below) may be exposed to the external space of the housing container 50 (the external space of the X-ray generator 100). The internal space of the housing container 50 is filled with an insulating liquid 60. From another perspective, the internal space of the housing container 50 is filled with the insulating liquid 60, except for the spaces occupied by the components housed in the housing container 50 (such as the X-ray generating tube 1 and the cable 42). The insulating liquid 60 may be, for example, an insulating oil such as mineral oil or synthetic oil. Alternatively, the insulating liquid 60 may be a liquid other than insulating oil, for example, a fluorine-based inert liquid (for example, Fluorinert (trademark)).

[0011] The X-ray generating tube 1 may include an insulating tube 10, a cathode 30, and an anode 20. The internal space of the X-ray generating tube 1 is maintained at a vacuum. The insulating tube 10 may have a first open end OP1 and a second open end OP2. The insulating tube 10 may have a tubular shape, such as a cylindrical shape. The insulating tube 10 may be configured to provide vacuum tightness and insulation for the internal space of the insulating tube 10. The insulating tube 10 may be made of a ceramic material containing, for example, alumina or zirconia as a main component. Alternatively, the insulating tube 10 may be made of a glass material, such as borosilicate glass.

[0012] The cathode 30 may be arranged to close the first open end OP1 of the insulating tube 10. The cathode 30 includes an electron emitting portion 32. In another aspect, the cathode 30 may include a closing member 31 arranged to close the first open end OP1 of the insulating tube 10, and an electron emitting portion 32 supported by the closing member 31. The surface of the closing member 31 may constitute the outer surface 34 of the cathode 30. The cathode 30 may be arranged so that a member at the cathode potential does not contact the insulating liquid 60. The anode 20 may be arranged to close the second open end OP2 of the insulating tube 10. The anode 20 may include a target 23 that generates X-rays when electrons from the electron emitting portion 32 collide with it. The anode 20 may include a target holding plate 22 that holds the target 23 and an electrode 21 that supports the target holding plate 22. The electrode 21 is made of a conductor and is electrically connected to the target 23 to apply a potential to the target 23. The anode 20 and the container 50 may be maintained at, for example, ground potential, but may also be maintained at other potentials. The target 23 may be made of a material with a high melting point and high X-ray generation efficiency, such as tungsten, tantalum, or molybdenum. The target holding plate 22 may be made of a material that is easily transparent to X-rays, such as beryllium or diamond.

[0013] The container 50 may have a third open end OP3. The container 50 may include, for example, a first portion 52, a second portion 53, a third portion 54, a fourth portion 55, and a fifth portion 56. The first portion 52 may have a cylindrical shape, such as a cylindrical shape. The first portion 52 may define the third open end OP3 of the container 50. In other words, the first portion 52 may have the third open end OP3. The second portion 53 is made of a conductor and is electrically connected to the anode 20 of the X-ray generating tube 1. The second portion 53 may be understood to constitute the anode together with the electrode 21. The second portion 53 may have a ring or frame shape. The second portion 53 may be arranged to contact the insulating liquid 60. Alternatively, the conductive member including the electrode 21 and the second portion 53 may be arranged to contact the insulating liquid 60. The electrode 21 and the second portion 53 may be formed as a single piece using the same material. The fourth portion 55 may have a cylindrical shape, such as a cylindrical or rectangular tube shape. The third portion 54 may be connected to one end of the fourth portion 55 and may have a ring or frame shape. The first portion 52 may be connected to the third portion 54 so as to protrude from the third portion 54. The fifth portion 56 may be connected to the other end of the fourth portion 55. Alternatively, the third portion 54, the fourth portion 55, and the fifth portion 56 may be integrated together to form a hollow spherical shape, excluding the joint portion with the first portion 52.

[0014] The insulating liquid 60 can convect in the internal space of the container 50. When the entire outer surface 14 of the insulating tube 10 is in contact with the insulating liquid 60, friction between the outer surface 14 of the insulating tube 10 and the insulating liquid 60 can cause the insulating tube 10 and the insulating liquid 60 to become electrically charged. This type of charging is called triboelectric charging. Generally, triboelectric charging refers to a phenomenon in which charge transfer occurs between two different materials due to friction, resulting in one material being positively charged and the other being negatively charged. The inventor conducted an experiment in which an insulating tube was left in convecting insulating oil (insulating liquid) and then the potential of the outer surface of the insulating tube was measured using a surface electrometer. As a result, it was confirmed that the outer surface of the insulating tube became positively charged and that the amount of charge increased in proportion to time. The polarity of the charge due to friction depends on the properties of the rubbing materials. Examples of material properties include the triboelectric series and the relative dielectric constant. Figure 7 shows an example of the triboelectric series for insulating oil. The triboelectric series indicates whether rubbed materials will be charged to a positive or negative polarity, and the order in which they are likely to be charged. Materials closer to the positive side of the triboelectric series are more likely to be charged to a positive polarity, and materials closer to the negative side are more likely to be charged to a negative polarity.

[0015] Positive charging of the outer surface 14 of the insulating tube 10 can reduce the insulating performance between the cathode 30 and the anode 20. The insulating performance between the cathode 30 and the anode 20 depends on factors such as the potential difference between the cathode 30 and the anode 20, the resistance between the cathode 30 and the anode 20, and the distance between the cathode 30 and the anode 20. Experimental results showed that when the insulating tube 10 is positively charged, the cathode 30 and the anode 20 are short-circuited via the outer surface 14 of the insulating tube 10, as schematically shown by the thick arrows in Figure 6. Experimental results also showed that abnormal discharge is likely to occur due to electron avalanches when the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 form a triple junction.

[0016] The X-ray generating device 100 of the present disclosure will be exemplarily described below through a number of embodiments shown in Figures 2, 3, 4, and 5. Items not mentioned below may follow the basic configuration described with reference to Figure 1.

[0017] FIG. 2 exemplarily and schematically illustrates the configuration of the X-ray generator 100 of the first embodiment. The container 50 may be filled with an insulating liquid 60 so as to contact a portion of the anode (e.g., the second portion 53) and cover the outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30. In the X-ray generator 100 of the first embodiment, at least a portion of the insulating tube 10 is surrounded by a member 72 to reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10. The member 72 may be made of an insulating material. More specifically, in the X-ray generator 100 of the first embodiment, the entire outer surface 34 of the insulating tube 10 may be surrounded by the member 72. From another perspective, the entire outer surface 14 of the insulating tube 10 may be covered by the member 72. Furthermore, the entire outer surface 34 of the cathode 30 may be covered by the member 72, in addition to the entire outer surface 14 of the insulating tube 10. The first embodiment is effective in preventing the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 from forming a triple point, thereby reducing the occurrence of abnormal discharge.

[0018] To reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10, the material of the member 72 may be selected so that the member 72 is negatively charged and the insulating liquid 60 is positively charged due to frictional charging between the member 72 and the insulating liquid 60. When insulating oil is used as the insulating liquid 60, the material of the member 72 may be selected, for example, according to the triboelectric series illustrated in FIG. 7 so that the member 72 is negatively charged due to frictional charging between the member 72 and the insulating oil. Suitable materials for the member 72 include, for example, polytetrafluoroethylene (Teflon™), PMMA (polymethyl methacrylate resin), epoxy, and fluororubber (e.g., Viton™). The member 72 may be disposed so as to cover the entire outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30. For this purpose, a molding method, a spraying method, a dipping method, or the like may be used.

[0019] In order to reduce abnormal discharge between the cathode 30 and the anode 20 via the insulating tube 10, the material of the member 72 can be determined so that the difference in dielectric constant between the member 72 and the insulating liquid 60 is smaller than the difference in dielectric constant between the member 72 and the insulating tube 10. For example, the member 72 is made of Viton, which has a dielectric constant of 3, or polytetrafluoroethylene, which has a dielectric constant of 2.1, and the insulating tube 10 is made of borosilicate glass, which has a dielectric constant of 4.9, or alumina, which has a dielectric constant of 9. Here, the fact that the difference in dielectric constant between the member 72 and the insulating liquid 60 is smaller than the difference in dielectric constant between the member 72 and the insulating tube 10 may be evaluated at the temperature at which X-rays are generated or at room temperature (e.g., 25°C). However, there is no significant difference between the former and latter.

[0020] Here, a molding method suitable for forming the member 72 to coat the X-ray generating tube 1 (the outer surface 14 of the insulating tube 10 and the outer surface 34 of the cathode 30) will be described. The material for the member 72, i.e., the coating material, can be prepared by kneading a base material and a curing aid in advance in a kneading device to prevent the inclusion of air bubbles, and maintaining a constant temperature to maintain proper fluidity. In the case of epoxy-based resin, the temperature is, for example, around 100°C, but this temperature can be determined appropriately depending on the material used. The coating material can be poured into a container slightly larger than the X-ray generating tube 1 to be coated. During this process, the temperature difference between the container and the coating material can cause the coating material to rapidly cool, reducing its fluidity. To prevent this, it is desirable to preheat the container. After the poured coating material overflows from the container, the coating material can be solidified at an appropriate cooling rate and temperature distribution to prevent problems such as shrinkage.

[0021] In the X-ray generating tube 1, a high voltage is applied between the anode 20 and the cathode 30. Therefore, if bubbles with a low dielectric constant are present in the member 72 made of the coating material, an electric field will concentrate there, potentially inducing abnormal discharge. To avoid this, the space in which the coating material is filled can be evacuated in advance using a vacuum pump to a vacuum level of several hundred to several thousand Pa. Furthermore, to improve adhesion between the coating material and the X-ray generating tube 1, a primer material may be applied to the surface of the X-ray generating tube 1, or unevenness may be formed by blasting before coating with the member 72. The thickness of the member 72 is desirably thin from the viewpoint of heat dissipation of the X-ray generating tube 1. The thickness of the member 72 is preferably, for example, 5 mm or less, and more preferably 3 mm or less. The thickness of the member 72 is preferably, for example, 0.3 mm or more, and more preferably 0.5 mm or more.

[0022] FIG. 3 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to the second embodiment. Matters not mentioned in the description of the second embodiment may follow the basic configuration described with reference to the first embodiment or FIG. 1 . The member 72 may be arranged so as to cover the contact portion C between the cathode 30 and the insulating tube 10. The member 72 may also be arranged so as to cover the cathode 30. The second embodiment is also effective in preventing the outer surface 14 of the insulating tube 10, the cathode 30, and the insulating liquid 60 from forming a triple point, thereby reducing the occurrence of abnormal discharge.

[0023] FIG. 4 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to a third embodiment. Details not mentioned in the description of the third embodiment may follow the basic configuration described with reference to the first or second embodiment or FIG. 1 . In the third embodiment, an intermediate layer 75 is provided between the member 72 and the insulating tube 10. The intermediate layer 75 may be made of an insulating material. The intermediate layer 75 may be configured to cover the insulating tube 10. The member 72 may be configured to cover the intermediate layer 75. The intermediate layer 75 may be made of at least one of Kovar glass, nylon, and a mixture containing a metal oxide primarily composed of silica. Providing the intermediate layer 75 is advantageous for forming a smooth surface covering the outer surface 14 of the insulating tube 10, for example. Furthermore, forming the intermediate layer 75 is advantageous for preventing foreign matter from penetrating between the particles that make up the insulating tube 10. As a result, the creepage withstand voltage on the surface of the member 72, which is arranged to cover the insulating tube 10, can be improved. This prevents abnormal discharge and extends the life of the X-ray generating device 100.

[0024] FIG. 5 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to a fourth embodiment. Details not mentioned in the description of the fourth embodiment may follow the basic configuration described with reference to the first to third embodiments or FIG. 1 . In the fourth embodiment, the member 72 may include a ring-shaped portion. Alternatively, the member 72 may be a ring-shaped portion. The ring-shaped portion may completely surround a portion of the outer surface 14 of the insulating tube 10 in the axial direction (the axial direction of the insulating tube 10, which is also the direction in which electron beams are emitted from the electron emitter 32). The outer surface 14 of the insulating tube 10 may be in contact with the insulating liquid 60 in a region other than the region surrounded by the member 72. The shortest distance between the member 72 and the cathode 30 is preferably shorter than the shortest distance between the member 72 and the anode 20. The insulating tube 10 may be surrounded by multiple members 72 (ring-shaped portions). The multiple members 72 may be arranged spaced apart from each other in the axial direction of the insulating tube 10. The member 72 may be made of, for example, Viton. Even if the outer surface 14 of the insulating tube 10 is positively charged, the member 72 is negatively charged, thereby reducing the amount of positive charge on the entire outer surface 14 of the insulating tube 10. This can reduce the occurrence of abnormal discharge.

[0025] FIG. 9 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to a fifth embodiment. Matters not mentioned in the description of the fifth embodiment may follow the basic configuration described with reference to the first to fourth embodiments or FIG. 1 . The container 50 may define a first space SP1 that houses the drive circuit 40 and a second space SP2 that protrudes from the first space SP1 and houses at least a portion of the X-ray generating tube 1. Another portion of the X-ray generating tube 1 may be disposed in the first space SP1. The third portion 54, the fourth portion 55, and the fifth portion 56 may define the first space SP1. Meanwhile, the first portion 52 and the second portion 53 may define the second space SP2. One end of the second space SP2 may form a third opening end OP3. The first portion 52 may form a protrusion protruding from the third portion 54. The second space SP2 may protrude from the first space SP1 and have the third opening end OP3.

[0026] The X-rays generated in the target 23 can be emitted in all directions. Therefore, the X-rays generated in the target 23 include backward X-rays 105, which are X-rays directed toward the inside of the X-ray generating device 100 (e.g., the cathode 30, the insulating tube 10), in addition to X-rays that are emitted outside the X-ray generating device 100 and irradiated onto the object to be measured.

[0027] 8 , a first insulating member 73 may be disposed in the space between the X-ray generating tube 1 and the first portion 52, i.e., the second space SP2. The first insulating member 73 may be disposed apart from the first portion 52 and the X-ray generating tube 1. The first insulating member 73 may be coupled to a third insulating member 77 disposed in the first space SP1 so as to surround the drive circuit 40. The third insulating member 77 may be disposed apart from the container 50.

[0028] The first insulating member 73 and the third insulating member 77 may be made of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), epoxy resin, polycarbonate, glass, or ceramics. The first insulating member 73 and the third insulating member 77 may also be made of a resin-impregnated glass cloth laminate (e.g., a laminated plate or laminated pipe) formed under heat and pressure. The resin-impregnated glass cloth laminate may be formed, for example, by laminating or winding a member (prepreg) in which a glass nonwoven fabric is impregnated with a resin such as epoxy resin or phenolic resin, followed by heat and pressure forming. The first insulating member 73 and the third insulating member 77 may also be made of glass epoxy, for example. The first insulating member 73 and the third insulating member 77 have a volume resistivity of 1×10 at 25°C. ５ It is preferable that the insulating property is Ωm or more.

[0029] As a result of continuing to generate X-rays in the X-ray generator 100 having the configuration shown in Fig. 8, a problem occurred in which abnormal discharge occurred between the first insulating member 73 and the X-ray generating tube 1. When the cause was investigated, it was found that the abnormal discharge occurred in a portion of the first insulating member 73 where the backward X-rays 105 were irradiated. Further investigation revealed that the first insulating member 73 became charged due to the irradiation of the backward X-rays 105, causing abnormal discharge to occur between the first insulating member 73 and a portion of the X-ray generating tube 1 facing it. However, if a space where the first insulating member 73 is not provided is provided in the portion irradiated with the backward X-rays 105, the insulating performance between the X-ray generating tube 1 and the first portion 52 will be reduced.

[0030] 9 , the area in which the first insulating member 73 is disposed is limited, and a second insulating member 74 is added. For ease of explanation, the second space SP2 is defined as a space including a third space SP3 and a fourth space SP4. The third space SP3 is a space into which X-rays (rear X-rays 105) from the target 23 enter without being blocked by either the cathode 30 or the anode 20. The fourth space SP4 is a space into which X-rays (rear X-rays 105) from the target 23 are blocked by either the cathode 30 (including the electron emitter 32) or the anode 20 (i.e., a space into which X-rays from the target 23 do not enter). In the fifth embodiment, the first insulating member 73 is disposed in the fourth space SP4, spaced apart from the insulating tube 10 and the container 50, so as to surround the insulating tube 10. The first insulating member 73 is not disposed in the third space SP3. The outer surface 14 of the insulating tube 10 has a first region R1 that is not surrounded by the first insulating member 73, and the first region R1 is surrounded by a second insulating member 74 that is arranged so as to be in contact with the first region R1. Here, it is preferable that the entire first region R1 is surrounded by the second insulating member 74. Note that the backward X-rays 105 include not only X-rays that arrive directly from the target 23, but also X-rays that are reflected by components such as the cathode 30 and the anode 20.

[0031] The outer surface 14 of the insulating tube 10 has a second region R2 between the first region R1 and the cathode 30, and the first insulating member 73 may be disposed to surround the entire second region R2. The first insulating member 73 may be disposed to extend from a fourth space SP4, which is part of the second space SP2, to the first space SP1. The second insulating member 74 may include a ring-shaped portion. The second insulating member 74 may be made of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), or epoxy resin.

[0032] As illustrated in FIG. 10 , the second insulating member 74 is preferably disposed so as to cover the contact portion (boundary) between the cathode 30 and the insulating tube 10. From another perspective, the second insulating member 74 can be disposed so as to cover at least a portion of the cathode 30, preferably the entire cathode 30. The second insulating member 74 is preferably disposed so as to cover the entire outer surface 14 of the insulating tube 10. As with the member 72 of the first embodiment, the second insulating member 74 can be applied to cover the outer surface 14 of the insulating tube 10 or disposed in the first region R1 by a molding method, a spraying method, a dipping method, or the like. Here, when applying the molding method, the second insulating member 74 may be molded separately from other members, i.e., as a single member, using a mold, or may be molded integrally with the insulating tube 10 using a mold such as insert molding.

[0033] A manufacturing method for the X-ray generator 100 as illustrated in FIG. 8 may include a step of inserting a first insulating member 73 into the gap between the X-ray generating tube 1 and the first portion 52. If the first insulating member 73 comes into contact with or collides with the X-ray generating tube 1 or the first portion 52 during this step, these components may be deformed or particles may be generated due to friction. Such deformation and particle generation may reduce the pressure resistance and cause abnormal discharge. In particular, the larger the dimension of the first insulating member 73 in the electron emission direction (axial direction of the X-ray generating tube 1), the more likely these problems will occur, potentially reducing the yield of the X-ray generator 100. Therefore, as illustrated in FIG. 9 , reducing the dimension of the first insulating member 73 in the electron emission direction (axial direction of the X-ray generating tube 1) is effective in improving the yield of the X-ray generator 100.

[0034] 11 , the entire insulating tube 10 (or the X-ray generating tube 1) may be disposed in the second space SP2. In other words, the dimension of the insulating tube 10 (or the X-ray generating tube 1) in the direction in which electrons are emitted (the axial direction of the X-ray generating tube 1) may be smaller than the dimension of the first portion 52. In this case, the cable 42 may be present on the boundary line between the first space SP1 and the second space SP2.

[0035] In the fifth embodiment, as in the first and fourth embodiments, measures for insulation between the cathode 30 and the anode 20 may also be taken.

[0036] FIG. 12 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to a sixth embodiment. Matters not mentioned in the description of the sixth embodiment may follow the basic configuration described with reference to the first to fifth embodiments or FIG. 1 . In the fifth embodiment illustrated in FIG. 9 , abnormal discharge due to rear X-rays 105 is suppressed by limiting the area where the first insulating member 73 is disposed. In the sixth embodiment, abnormal discharge due to rear X-rays 105 is suppressed without limiting the area where the first insulating member 73 (insulating partition wall) is disposed. In the sixth embodiment illustrated in FIG. 12 , an X-ray shielding member 80 is provided. The X-ray shielding member 80 may be disposed such that a portion of the outer surface 14 of the insulating tube 10 is surrounded by the X-ray shielding member 80. The X-ray shielding member 80 may extend from the anode 20 toward (the blocking member 31 of) the cathode 30 so as to block X-rays (rear X-rays 105). The X-ray shielding member 80 can be disposed so as to extend from the anode 20 to a position between the anode 20 and (the blocking member 31 of) the cathode 30. By providing the X-ray shielding member 80, it is possible to eliminate or reduce the aforementioned third space SP3, i.e., the space into which X-rays (rear X-rays 105) from the target 23 enter without being blocked by either the cathode 30 or the anode 20.

[0037] From the viewpoint of stabilizing the potential of the X-ray shielding member 80, it is desirable that the X-ray shielding member 80 be at the same potential as the anode 20 (in a state of electrical connection with the anode 20); however, it may be at a different potential. The X-ray shielding member 80 is desirably made of a material that easily blocks X-rays, particularly a metal material. The X-ray shielding member 80 may also be made of a bulk metal material or a thin metal film of 100 μm or less. Because a gap between the X-ray shielding member 80 and the insulating tube 10 could cause dielectric breakdown, the X-ray shielding member 80 can be disposed so as to contact the outer surface 14 of the insulating tube 10. The X-ray shielding member 80 can be formed, for example, by a plating method or a PVD method so as to contact the outer surface 14 of the insulating tube 10.

[0038] A potential different from that of the cathode 30, for example, the potential of the anode 20, may be applied to the X-ray shielding member 80. In this case, the creepage distance between the cathode 30 and the X-ray shielding member 80 becomes shorter than the creepage distance between the cathode 30 and the anode 20 when the X-ray shielding member 80 is not provided. This may cause abnormal discharge. Therefore, it is preferable that the X-ray shielding member 80 be covered with an insulating member 74. The insulating member 74 may be arranged to cover the contact portion (boundary) between the X-ray shielding member 80 and the insulating tube 10. The insulating member 74 may also be arranged to cover the exposed portion of the outer surface 14 of the insulating tube 10 (the portion not covered by the X-ray shielding member 80). Preferably, the insulating member 74 may be arranged to cover the entire X-ray shielding member 80 and the entire exposed portion of the outer surface 14 of the insulating tube 10. Furthermore, the insulating member 74 can be arranged so as to cover the contact portion (boundary) between the cathode 30 (the blocking member 31 thereof) and the insulating tube 10. The insulating member 74 can be arranged so as to contact the outer surface of the X-ray shielding member 80. The outer surface 34 of the cathode 30 (the blocking member 31 thereof) has a cylindrical side surface and a circular bottom surface, and at least the entire side surface of the outer surface 34 of the cathode 30 can be covered with the insulating member 74. Furthermore, it is preferable that the entire outer surface 34 of the cathode 30 be covered with the insulating member 74.

[0039] A first insulating member 73 (insulating partition wall) may be arranged in the second space SP2 at a distance from the insulating tube 10 and the container 50 so as to surround the insulating tube 10 and the insulating member 74, but the first insulating member 73 does not have to be arranged. If the first insulating member 73 is not arranged, the X-ray shielding member 80 can suppress abnormal discharge caused by the backward X-rays 105 charging the first portion 52 of the container 50 (for example, when the first portion 52 is made of an insulator, or when the first portion 52 is made of a conductor but is in a floating state), the insulating liquid 60, or the second insulating member 74.

[0040] 13 , the X-ray shielding member 80 does not need to block all of the rear X-rays 105. Extending the X-ray shielding member 80 toward the cathode 30 can shorten the creepage distance. Therefore, the extension range of the X-ray shielding member 80 or the range over which the X-ray shielding member 80 covers the insulating tube 10 can be determined by taking into consideration both the disadvantage of shortening the creepage distance and the advantage of blocking the rear X-rays 105. From another perspective, the extension range of the X-ray shielding member 80 can be determined depending on the intensity distribution of the rear X-rays 105.

[0041] FIG. 14 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to a seventh embodiment. Details not mentioned in the description of the seventh embodiment may follow the basic configuration described with reference to the first to sixth embodiments or FIG. 1 . In one aspect of the seventh embodiment, the outer surface 14 of the insulating tube 10 is surrounded by an insulating member 74, and an adhesion layer 81 is provided between the outer surface 14 of the insulating tube 10 and the insulating member 74. Providing the adhesion layer 81 improves adhesion between the outer surface 14 of the insulating tube 10 and the insulating member 74. This reduces air bubbles and / or gaps between the outer surface 14 of the insulating tube 10 and the insulating member 74, potentially reducing a decrease in dielectric strength and the occurrence of abnormal discharge. The insulating member 74 may be disposed so as to cover the boundary between the cathode 30 (the blocking member 31 thereof) and the insulating tube 10. The adhesion layer 81 and the insulating member 74 may be disposed so as to cover the entire outer surface 34 of the insulating tube 10. The adhesion layer 81 may be formed of, for example, a silane coupling agent. The adhesion layer 81 may be made of a titanium coupling agent.

[0042] In another aspect, the X-ray generating device 100 of the seventh embodiment may include the X-ray shielding member 80 described in the sixth embodiment. When the X-ray shielding member 80 is included, the adhesive layer 81 may also be disposed between the insulating member 74 and the X-ray shielding member 80.

[0043] FIG. 15 exemplarily and schematically illustrates the configuration of an X-ray generator 100 according to an eighth embodiment. Details not mentioned in the description of the eighth embodiment may follow the basic configuration described with reference to the first to seventh embodiments or FIG. 1 . In one aspect of the eighth embodiment, the outer surface 14 of the insulating tube 10 is surrounded by an insulating member 74, and an adhesive layer 81 is provided between the outer surface 14 of the insulating tube 10 and the insulating member 74. Providing the adhesive layer 81 improves adhesion between the outer surface 14 of the insulating tube 10 and the insulating member 74. This reduces air bubbles and / or gaps between the outer surface 14 of the insulating tube 10 and the insulating member 74, potentially reducing a decrease in dielectric strength and the occurrence of abnormal discharge. The insulating member 74 may be disposed so as to cover the boundary between the cathode 30 (the blocking member 31 thereof) and the insulating tube 10. The adhesive layer 81 and the insulating member 74 may be disposed so as to cover the entire outer surface 34 of the insulating tube 10. The adhesive layer 81 may be formed of, for example, a silane coupling agent. The adhesion layer 81 may be made of a titanium coupling agent.

[0044] In the eighth embodiment, the X-ray generating device 100 does not include the first insulating member 73, the third insulating member 77, and the X-ray shielding member 80. However, by providing the adhesion layer 81 between the outer surface 14 of the insulating tube 10 and the insulating member 74, the occurrence of abnormal discharge can be reduced.

[0045] FIG. 16 shows the configuration of an X-ray imaging apparatus 200 according to one embodiment. The X-ray imaging apparatus 200 may include an X-ray generator 100 and an X-ray detection device 110 that detects X-rays 104 emitted from the X-ray generator 100 and transmitted through an object 106. The X-ray imaging apparatus 200 may further include a control device 120 and a display device 130. The X-ray detection device 110 may include an X-ray detector 112 and a signal processing unit 114. The control device 120 may control the X-ray generator 100 and the X-ray detection device 110. The X-ray detector 112 detects or captures the X-rays 104 emitted from the X-ray generator 100 and transmitted through the object 106. The signal processing unit 114 may process a signal output from the X-ray detector 112 and supply the processed signal to the control device 120. The control device 120 causes the display device 130 to display an image based on the signal supplied from the signal processing unit 114.

[0046] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention.

Claims

1. an X-ray generating tube including: an insulating tube having a first open end and a second open end; a cathode arranged to close the first open end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; a drive circuit for driving the X-ray generating tube; a housing that houses the X-ray generating tube and the drive circuit, the container has a third open end, and the X-ray generating tube is disposed so as to close the third open end; The container is filled with an insulating liquid, the container defines a first space for accommodating the drive circuit and a second space protruding from the first space for accommodating at least a portion of the X-ray generating tube; the container includes a protrusion surrounding the second space, and one end of the second space constitutes the third opening end; a portion of an outer surface of the insulating tube is surrounded by an X-ray shielding member extending from the anode toward the cathode so as to block X-rays; The X-ray shielding member is covered with an insulating member. An X-ray generating device characterized by:

2. the X-ray shielding member extends from the anode to a position between the anode and the cathode; 2. The X-ray generating device according to claim 1.

3. the X-ray shielding member is in contact with the outer surface of the insulating tube; 2. The X-ray generating device according to claim 1.

4. the insulating member is in contact with the X-ray shielding member; 4. The X-ray generating device according to claim 3.

5. The insulating member covers the entire outer surface of the X-ray shielding member.

2. The X-ray generating device according to claim 1.

6. an insulating partition wall is disposed in the second space so as to surround the insulating pipe and the insulating member and be spaced apart from the insulating pipe and the container; 2. The X-ray generating device according to claim 1.

7. the outer surface of the cathode has a cylindrical side surface and a circular bottom surface; At least the entire side surface of the outer surface of the cathode is covered with the insulating member.

2. The X-ray generating device according to claim 1.

8. the entire outer surface of the cathode is covered with the insulating member; 8. The X-ray generating device according to claim 7.

9. The insulating tube is entirely disposed in the second space.

2. The X-ray generating device according to claim 1.

10. an adhesive layer is provided between the outer surface of the insulating tube and the insulating member; 2. The X-ray generating device according to claim 1.

11. The adhesion layer contains a silane coupling agent.

11. The X-ray generating device according to claim 10.

12. an X-ray generating tube including: an insulating tube having a first open end and a second open end; a cathode arranged to close the first open end of the insulating tube and including an electron emitting portion; and an anode arranged to close the second open end and including a target that generates X-rays when electrons from the electron emitting portion collide with the target; a drive circuit for driving the X-ray generating tube; a housing that houses the X-ray generating tube and the drive circuit, the container has a third open end, and the X-ray generating tube is disposed so as to close the third open end; The container is filled with an insulating liquid, the container defines a first space for accommodating the drive circuit and a second space protruding from the first space for accommodating at least a portion of the X-ray generating tube; the container includes a protrusion surrounding the second space, and one end of the second space constitutes the third opening end; an outer surface of the insulating tube is surrounded by an insulating member, and an adhesive layer is provided between the outer surface of the insulating tube and the insulating member; An X-ray generating device characterized by:

13. the insulating member is disposed so as to cover the boundary between the cathode and the insulating tube.

13. The X-ray generating device according to claim 12.

14. the adhesive layer and the insulating member are arranged to cover the entire outer surface of the insulating tube.

13. The X-ray generating device according to claim 12.

15. The insulating member is made of any one of polytetrafluoroethylene, PMMA (polymethyl methacrylate resin), and epoxy resin.

13. The X-ray generating device according to claim 12.

16. The insulating liquid is insulating oil.

16. An X-ray generating device according to any one of claims 1 to 15.

17. An X-ray generator according to any one of claims 1 to 15; an X-ray detector that detects X-rays emitted from the X-ray generator; An X-ray imaging device comprising: