X-ray generator

Abstract

To effectively suppress discharge in the power source unit of an X-ray generator.SOLUTION: An x-ray generator 1A includes: a housing 2; an electron gun 3; a target 4; and a power unit 6. The power unit 6 includes: an insulation unit 61; and a circuit unit 62 embedded in the insulation unit 61. The insulation unit 61 includes: a base material made of a first insulating material; and a plurality of particles made of a second insulating material having a higher insulating property than the first insulating material and dispersed in the base material. The circuit unit 62 includes: a first voltage unit 62a; a pressure rising unit 62b; and a second voltage unit 62c. In the insulation unit 61, the volume concentration of the plurality of particles in a first region 611 is higher than the volume concentration of the plurality of particles in a second region 612, and the volume concentration of the plurality of particles in the second region 612 is higher than the volume concentration of the plurality of particles in a third region 613. The circuit unit 62 is embedded in the insulation unit 61 such that at least a part of the circuit unit 62 is located in the second region 612.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an X-ray generating device. [Background technology]

[0002] Known X-ray generators include a housing, an electron gun that emits an electron beam within the housing, a target that generates X-rays when the electron beam is incident on it within the housing, and a power supply unit that generates a voltage to be applied to the electron gun or the target, where the power supply unit has an insulating unit and a circuit unit embedded in the insulating unit (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-213974 Summary of the Invention [Problem to be solved by the invention]

[0004] In the X-ray generator described above, the circuit unit is embedded in the insulating unit, thereby suppressing the occurrence of discharge in the power supply unit, and as a result, the reliability of the X-ray generator is improved. In order to further improve the reliability of such an X-ray generator, it is desirable to effectively suppress the occurrence of discharge in the power supply unit.

[0005] An object of the present invention is to provide an X-ray generator that can effectively suppress the occurrence of discharge in a power supply unit. [Means for solving the problem]

[0006] The X-ray generator of the present invention is [1] "comprised of a housing, an electron gun that emits an electron beam within the housing, a target that generates X-rays when the electron beam is incident within the housing, and a power supply unit that generates a voltage to be applied to the electron gun or the target, the power supply unit having an insulating unit and a circuit unit embedded in the insulating unit, the insulating unit including a base made of a first insulating material and a plurality of particles that are made of a second insulating material having higher insulating properties than the first insulating material and are dispersed in the base, the circuit unit including a first voltage unit to which a first voltage is input from the outside, and a second voltage unit that outputs the second voltage, an X-ray generating device including a boosting unit that boosts the first voltage and a second voltage unit that outputs the second voltage to the electron gun or the target, wherein in the insulating unit, the volume concentration of the plurality of particles in a first region is higher than the volume concentration of the plurality of particles in a second region on one side of the first region in a first direction, and the volume concentration of the plurality of particles in the second region is higher than the volume concentration of the plurality of particles in a third region on the one side of the second region in the first direction, and the circuit unit is embedded in the insulating unit such that at least a portion of the circuit unit is located in the second region.

[0007] In the X-ray generator described in [1] above, the insulating section includes a base material made of a first insulating material and a plurality of particles made of a second insulating material having higher insulating properties than the first insulating material and dispersed in the base material. Here, in the insulating section, the insulating performance improves as the volume concentration of the plurality of particles increases. However, if the volume concentration of the plurality of particles becomes too high, discharges are likely to occur along the surfaces of the plurality of particles that contact each other. In the X-ray generator described in [1] above, in the insulating section, the volume concentration of the plurality of particles in the first region is higher than the volume concentration of the plurality of particles in the second region on one side of the first region in the first direction, and the volume concentration of the plurality of particles in the second region is higher than the volume concentration of the plurality of particles in the third region on one side of the second region in the first direction. This ensures high insulating performance in the insulating section while suppressing discharges caused by an excessively high volume concentration of the plurality of particles in the second region. In the X-ray generator described in [1] above, the circuit section is embedded in the insulating section so that at least a portion of the circuit section is located in the second region. This allows at least a part of the circuit unit to be located in a region of the insulating unit that has high insulating performance. Therefore, according to the X-ray generating device described in [1] above, it is possible to effectively suppress the occurrence of discharge in the power supply unit.

[0008] The X-ray generator of the present invention may be [2] "the X-ray generator according to the above [1], wherein the volume concentration of the plurality of particles in the second region is 5% or more and 75% or less." According to the X-ray generator according to [2], it is possible to reliably suppress the occurrence of discharge in the second region due to an excessively high volume concentration of the plurality of particles, while reliably ensuring high insulating performance in the insulating section. Therefore, it is possible to reliably position at least a portion of the circuit section in a region of the insulating section that has high insulating performance. Therefore, according to the X-ray generator according to [2], it is possible to more effectively suppress the occurrence of discharge in the power supply section.

[0009] The X-ray generator of the present invention may be [3] "the X-ray generator according to the above [2], wherein at least the part of the circuit unit is located in a region of the second region where the volume concentration of the plurality of particles is 20% or more and 60% or less." According to the X-ray generator according to [3], at least the part of the circuit unit can be more reliably located in a region of the insulating unit that has high insulating performance. Therefore, according to the X-ray generator according to [3], it is possible to more effectively suppress the occurrence of discharge in the power supply unit.

[0010] The X-ray generator of the present invention may be [4] "the X-ray generator according to any one of the above [1] to [3], wherein the circuit unit is embedded in the insulating unit so that the second voltage unit is located in the second region." According to the X-ray generator described in [4], the second voltage unit, which is likely to cause discharge in the circuit unit, is located in the second region, so that discharge in the power supply unit can be more efficiently suppressed.

[0011] The X-ray generator of the present invention may be the X-ray generator according to [4], wherein [5] "the power supply unit further includes a power supply unit electrically connecting the second voltage unit and the electron gun or the target, the electron gun or the target overlapping the second region when viewed from a second direction perpendicular to the first direction, and the circuit unit is embedded in the insulating unit such that the second voltage unit is located between the first voltage unit and the electron gun or the target in the second direction." The X-ray generator according to [5] can easily realize a configuration in which the power supply unit, which is likely to cause discharge, passes through the second region, thereby more efficiently suppressing discharge within the power supply unit.

[0012] The X-ray generator of the present invention may be [6] "the X-ray generator according to any one of the above [1] to [5], wherein the circuit unit is embedded in the insulating part so that the entire circuit unit is located in the second region." According to the X-ray generator according to [6], it is possible to more effectively suppress the occurrence of discharge in the power supply unit.

[0013] The X-ray generator of the present invention may be [7] "the X-ray generator according to [6], wherein the circuit unit is embedded in the insulating unit so that the second voltage unit is located on the first region side relative to the first voltage unit." According to the X-ray generator according to [7], the second voltage unit, which is likely to cause discharge, is located in the region on the first region side in the second region, so that discharge in the power supply unit can be more efficiently suppressed. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an X-ray generator that can effectively suppress the occurrence of discharge in the power supply unit. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of an X-ray generator according to a first embodiment. [Figure 2] FIG. 10 is a cross-sectional view of an X-ray generator according to a second embodiment. [Figure 3] 3 is a cross-sectional view of a portion of the X-ray generating device shown in FIG. 2. [Figure 4] FIG. 10 is a cross-sectional view of a modified X-ray generating device. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted. [X-ray generating device of the first embodiment]

[0017] 1, the X-ray generator 1A of the first embodiment includes a housing 2, an electron gun 3, a target 4, an anode 5, a power supply unit 6, and a power application unit 7. The X-ray generator 1A is a microfocus X-ray source used, for example, in X-ray nondestructive testing.

[0018] The housing 2 accommodates the electron gun 3, the target 4, and the anode 5. The space within the housing 2 is a vacuum space. The housing 2 includes a head 21, a bulb 22, and a flange 23. The head 21 is formed into a cylindrical shape with a bottom from a metal material such as stainless steel. The bulb 22 is formed into a cylindrical shape with a bottom from an insulating material such as glass. The head 21 is airtightly joined to the bulb 22 so that the interior of the head 21 is in communication with the interior of the bulb 22. The flange 23 is formed into a circular shape along the outer edge of the head 21 from a metal material such as stainless steel. Here, the direction along the central axis (tube axis) A1 of the bulb 22 is referred to as the Z-axis direction (second direction), the direction perpendicular to the Z-axis direction is referred to as the X-axis direction (first direction), and the direction perpendicular to both the Z-axis direction and the X-axis direction is referred to as the Y-axis direction.

[0019] The electron gun 3 emits an electron beam toward the target 4 inside the housing 2. The electron gun 3 is composed of a hot cathode that emits thermal electrons, an extraction electrode that extracts electrons, and an electron lens that adjusts the convergence of the electron beam (all not shown). The electron gun 3 may have a cold cathode instead of the hot cathode. The electron gun 3 is fixed to the head 21 so that the central axis A2 of the electron gun 3 is perpendicular to the central axis A1 of the bulb 22. The central axis A2 of the electron gun 3 is aligned along the X-axis direction.

[0020] The target 4 generates X-rays when the electron beam emitted from the electron gun 3 is incident on it within the housing 2. The target 4 is formed into a plate shape from a high-melting point metal material such as tungsten. The target 4 is supported by the anode 5 within the housing 2 so as to face the electron gun 3 in the X-axis direction. The target 4 may be formed integrally with the anode 5.

[0021] The anode 5 applies a voltage generated in the power supply unit 6 to the target 4. Therefore, the anode 5 is electrically connected to the target 4. The anode 5 is formed in a rod shape extending along the Z-axis direction from a metal material such as copper. The anode 5 extends from the outside to the inside of the housing 2 so that the central axis of the anode 5 coincides with the central axis A1 of the bulb 22. The anode 5 is fixed to the bottom of the bulb 22. The tip surface of the anode 5 within the housing 2 is an inclined surface inclined with respect to both the central axis A1 and the central axis A2. The target 4 is embedded in the tip portion 5a of the anode 5 so as to be flush with the tip surface of the anode 5.

[0022] The power supply unit 6 generates a voltage to be applied to the target 4 via the power application unit 7 and the anode 5. The power supply unit 6 is disposed on one side in the Z-axis direction (below the housing 2) with respect to the housing 2. The power supply unit 6 has an insulating unit 61, a circuit unit 62, wiring (power supply unit) 63, and a power supply unit (not shown) that electrically connects the circuit unit 62 to an external power source.

[0023] The insulating section 61 electrically insulates the circuit section 62 and the wiring 63 from other components. The insulating section 61 is formed in a rectangular parallelepiped shape. The surface 61a of the insulating section 61 is composed of an upper surface 61b which is the surface facing the housing 2, a lower surface 61c opposite the upper surface 61b, and a side surface 61d which connects the upper surface 61b and the lower surface 61c to each other. A ring-shaped wall section 61e is formed in the center of the upper surface 61b.

[0024] The insulating portion 61 includes a substrate made of a first insulating material and a plurality of particles dispersed in the substrate, the particles being made of a second insulating material having higher insulating properties than the first insulating material. Insulation refers to the strength of the electric field required to cause dielectric breakdown. A second insulating material having higher insulating properties than the first insulating material means that the electric field required to cause dielectric breakdown is stronger for the second insulating material than for the first insulating material. High insulation can also be interpreted as high dielectric strength or high withstand voltage. Furthermore, in addition to insulation, it is preferable that the second insulating material has higher heat resistance than the first insulating material. Higher heat resistance for the second insulating material than the first insulating material means that the temperature at which changes such as deformation or decomposition begin to occur when heated is higher for the second insulating material than for the first insulating material. High heat resistance can also be interpreted as a high heat resistance temperature. The reasons for incorporating a second insulating material into a substrate made of a first insulating material are as follows. When a high voltage is applied inside the insulating portion 61, a tree (a discharge mark that develops due to partial discharge) may develop from the portion where the high voltage is applied. If the tree develops and reaches ground potential (e.g., the side surface 61d of the insulating portion 61), a short-circuit path is formed between the portion where the high voltage is applied and ground potential, making discharge more likely to occur inside the insulating portion 61. Therefore, by adding a second insulating material, the tree can develop along a path along the interface between the first insulating material and the second insulating material. In other words, by including the second insulating material, the tree can be prevented from developing along a linear path in the first insulating material, thereby increasing the distance the tree takes to reach ground potential. In this case, if the tree (discharge) develops inside the second insulating material, the effect of increasing the distance due to tree development along a path along the interface as described above cannot be obtained. Therefore, it is preferable that the second insulating material have higher insulating properties than the first insulating material. Furthermore, since thermal breakdown caused by heating due to partial discharge is believed to be one of the mechanisms by which trees progress inside the insulating portion 61, it is preferable that the second insulating material have higher heat resistance than the first insulating material.The first insulating material is, for example, a resin material such as epoxy resin, and the plurality of particles is, for example, an inorganic filler such as silica or alumina.

[0025] The insulating portion 61 is composed of a first region 611, a second region 612, and a third region 613. Each of the first region 611, the second region 612, and the third region 613 is a rectangular parallelepiped region. The second region 612 is located on one side of the first region 611 in the X-axis direction (the right side in FIG. 1). The third region 613 is located on one side of the second region 612 in the X-axis direction (the right side in FIG. 1). That is, the first region 611, the second region 612, and the third region 613 are arranged in this order along the X-axis direction.

[0026] The volume concentration of the particles in the first region 611 (hereinafter also referred to as the "first volume concentration") is higher than the volume concentration of the particles in the second region 612 (hereinafter also referred to as the "second volume concentration"). The second volume concentration is higher than the volume concentration of the particles in the third region 613 (hereinafter also referred to as the "third volume concentration"). In this specification, the "volume concentration of the particles" refers to the proportion of the volume occupied by the particles per unit volume. In the X-ray generation device 1A, the first volume concentration at an arbitrary position in the first region 611 is higher than the second volume concentration at an arbitrary position in the second region 612, and the second volume concentration at an arbitrary position in the second region 612 is higher than the third volume concentration at an arbitrary position in the third region 613. In other words, the minimum value of the first volume concentration in the first region 611 is higher than the maximum value of the second volume concentration in the second region 612, and the minimum value of the second volume concentration in the second region 612 is higher than the maximum value of the third volume concentration in the third region 613.

[0027] The volume concentration of the multiple particles in the insulating portion 61 continuously increases from the end of the third region 613 opposite the second region 612 to the end of the first region 611 opposite the second region 612. That is, the third volume concentration increases from the end of the third region 613 opposite the second region 612 to the second region 612 side in the X-axis direction. The second volume concentration increases from the third region 613 side to the first region 611 side in the X-axis direction. The first volume concentration increases from the second region 612 side to the end of the first region 611 opposite the second region 612 in the X-axis direction.

[0028] The first volume concentration is greater than 75% and less than 100%, the second volume concentration is greater than 5% and less than 75%, and the third volume concentration is greater than 0% and less than 5%. The first volume concentration may be greater than 60% and less than 100%, the second volume concentration may be greater than 20% and less than 60%, and the third volume concentration may be greater than 0% and less than 20%. The first volume concentration, the second volume concentration, and the third volume concentration are measured by, for example, image analysis, gel permeation chromatography, etc.

[0029] The circuit unit 62 has a substrate 621, which is a rectangular printed circuit board. The surface of the substrate 621 is perpendicular to the Y-axis direction. A first voltage unit 62a, a boost unit 62b, and a second voltage unit 62c are mounted on the surface of the substrate 621. The first voltage unit 62a includes an input terminal to which a first voltage is input from outside via a power supply unit (not shown) and is electrically connected to the boost unit 62b. The boost unit 62b includes a boost circuit that boosts the first voltage to a second voltage. The boost unit 62b is, for example, a Cockcroft-Walton circuit. The second voltage unit 62c includes an output terminal that outputs a second voltage to be applied to the target 4 and is electrically connected to the boost unit 62b. The output terminal outputs the second voltage to the target 4 via wiring 63, the power application unit 7, and the anode 5. In other words, relatively speaking, the first voltage section 62a can be said to be the low-voltage section of the circuit section 62, and the second voltage section 62c can be said to be the high-voltage section of the circuit section 62. The boost section 62b can also be said to be substantially included in the high-voltage section of the circuit section 62. In other words, the substrate 621 includes a relatively low-voltage region in which the first voltage section 62a is arranged, and a relatively high-voltage region in which the boost section 62b and the second voltage section 62c are arranged. Note that the surface of the substrate 621 may be orthogonal to either the X-axis direction or the Z-axis direction. It does not matter which of the two surfaces of the substrate 621 is the surface of the substrate 621 (the surface on which the first voltage section 62a, etc. are mounted).

[0030] The booster 62b is located in the center of the surface of the substrate 621. The first voltage unit 62a is located on one side (the lower surface 61c side) of the booster 62b in the Z-axis direction. The second voltage unit 62c is located on the other side (the upper surface 61b side) of the booster 62b in the Z-axis direction.

[0031] The circuit unit 62 is embedded in the insulating unit 61 so that the entire circuit unit 62 is located in the second region 612. The circuit unit 62 is embedded in the insulating unit 61 so that at least the boosting unit 62b and the second voltage unit 62c (i.e., the high-voltage region of the circuit unit 62) are located in a region of the second region 612 where the second volume concentration is 20% or more and 60% or less. In this embodiment, the entire circuit unit 62 is located in a region of the second region 612 where the second volume concentration is 20% or more and 60% or less. The circuit unit 62 is embedded in the insulating unit 61 so that the substrate 621 extends straight along the Z-axis direction.

[0032] The wiring 63 electrically connects the second voltage unit 62c and the target 4 via the power application unit 7 and the anode 5. One end of the wiring 63 is electrically connected to the second voltage unit 62c, and the other end of the wiring 63 is connected to the power application unit 7. In this embodiment, the wiring 63 is made of, for example, a copper wire and a coating material coating the copper wire, but it may also be a plate or rod made of a conductive material. The wiring 63 is embedded in the insulating unit 61 so that at least a portion of the wiring 63 is located in the second region 612. In the X-ray generator 1A, the wiring 63 is entirely embedded in the second region 612 of the insulating unit 61 so that the portion of the wiring 63 is aligned along the Z-axis direction.

[0033] The power application unit 7 supplies the second voltage output from the second voltage unit 62c to the target 4. The power application unit 7 is a cylindrical socket made of a metal material such as aluminum. The power application unit 7 is embedded in the insulating unit 61 so that a portion 7a of the power application unit 7 is exposed outside the insulating unit 61. The portion 7a protrudes from the upper surface 61b to the outside of the insulating unit 61. The portion 7a is surrounded by the wall portion 61e when viewed from the Z-axis direction. The base end portion 5b of the anode 5 is fitted into the portion 7a. The portion of the power application unit 7 embedded in the insulating unit 61 is located in the second region 612.

[0034] When viewed from the Z-axis direction, the target 4, the anode 5, and the power application unit 7 overlap with the second region 612. The circuit unit 62 is embedded in the insulating unit 61 so that the second voltage unit 62c is located between the first voltage unit 62a and the target 4 in the Z-axis direction.

[0035] The X-ray generator 1A further includes a first plate member 11, a second plate member 12, a plurality of (four in this embodiment) support columns 13, a cylindrical member 14, insulating oil 15, and conductive paint 16. The conductive paint 16 is applied to a side surface 61d of the insulating portion 61, and the potential of the side surface 61d is set to ground potential.

[0036] The first plate member 11 is formed into a rectangular plate shape from a metal material such as aluminum. The insulating part 61 is disposed on the first plate member 11 so that the lower surface 61c of the insulating part 61 contacts the first plate member 11. The second plate member 12 is formed into a rectangular plate shape from a metal material such as aluminum. The second plate member 12 is disposed on the insulating part 61 so that the upper surface 61b of the second plate member 12 contacts the second plate member 12. An opening 12a is provided in the second plate member 12. The wall part 61e and the power applying part 7 are located inside the opening 12a when viewed from the Z-axis direction.

[0037] Each of the multiple support columns 13 is disposed between one of the four corners of the first plate member 11 and one of the four corners of the second plate member 12. The support columns 13 are formed in a rectangular parallelepiped shape from a metal material such as aluminum. The first plate member 11 and the second plate member 12 are fixed to each other via the support columns 13. Specifically, the shank of a screw S1 is inserted through a through hole provided in the first plate member 11 and the second plate member 12 and is screwed into a screw hole provided in the support columns 13. This fixes the first plate member 11 and the second plate member 12 to each other.

[0038] The tubular member 14 accommodates insulating oil 15. The tubular member 14 is formed into a cylindrical shape from a metal material such as aluminum. The tubular member 14 is disposed on the second plate member 12 so that the interior of the tubular member 14 is in communication with the opening 12a. A valve 22 and an anode 5 are located inside the tubular member 14. One end 14a of the tubular member 14 is tapered, with the diameter decreasing toward the tip end surface of the tubular member 14. A flange 23 is screwed to the tip end surface of the tubular member 14 via a sealing member (not shown). A flange 14b is formed at the other end of the tubular member 14. The flange 14b is screwed to the second plate member 12 via a sealing member (not shown). An internal space is defined by the inner surface of the opening 12a, the inner surface of the tubular member 14, the flange 23, and the insulating portion 61. The internal space is filled with insulating oil 15, the main component of which is, for example, mineral oil. The insulating oil 15 covers the bulb 22, the part of the anode 5 that is exposed to the outside of the housing 2, and the part of the power applying unit 7 that is exposed to the outside of the insulating unit 61.

[0039] In the X-ray generator 1A configured as described above, the side surface 61d of the insulating unit 61 is set to ground potential, and a voltage of, for example, several hundred volts is input as a first voltage from an external power supply via a power supply unit to the first voltage unit 62a. The booster unit 62b boosts the first voltage to a second voltage of, for example, several kV to several hundred kV. The second voltage unit 62c then outputs the second voltage to the target 4 via the wiring 63, the power application unit 7, and the anode 5. With the second voltage applied to the target 4, an electron beam from the electron gun 3 is incident on the target 4, causing X-rays to be generated from the target 4. The X-ray generator 1A is a so-called sealed reflection X-ray generator. Power may be supplied to the electron gun 3 by a transformer (not shown) included in the power supply unit 6, or by the circuit unit 62.

[0040] The power supply unit 6 of the X-ray generator 1A is manufactured, for example, as follows. First, the circuit unit 62, the wiring 63, and the power applying unit 7 are arranged at predetermined positions in a mold. In this state, a thermosetting resin containing a plurality of particles is introduced into the mold. The thermosetting resin is then thermally cured in the mold to form the insulating unit 61. To form the first region 611, the second region 612, and the third region 613, each having a different volume concentration of the plurality of particles, for example, three types of thermosetting resins each containing a different amount of the plurality of particles are prepared and introduced into the mold in a desired order. Alternatively, the three regions can be formed using only one type of thermosetting resin containing a plurality of particles. In this case, the fact that the particles settle due to gravity when the thermosetting resin is thermally cured is utilized. As a result, the volume concentration of the particles continuously increases or decreases along the direction of gravity when the insulating unit 61 is formed. Therefore, as described above, the first region 611, the second region 612, and the third region 613, which have different volume concentrations of the plurality of particles from one another, are formed in the insulating portion 61. [Action and effect]

[0041] As described above, in the X-ray generator 1A, the insulating section 61 includes a base material made of a first insulating material and a plurality of particles made of a second insulating material having higher insulating properties than the first insulating material and dispersed in the base material. Here, in the insulating section 61, the insulating performance improves as the volume concentration of the plurality of particles increases. However, if the volume concentration of the plurality of particles becomes too high, discharges are likely to occur along the surfaces of the plurality of particles that contact each other. In the X-ray generator 1A, in the insulating section 61, the volume concentration of the plurality of particles in the first region 611 is higher than the volume concentration of the plurality of particles in the second region 612 on one side of the first region 611 in the X-axis direction, and the volume concentration of the plurality of particles in the second region 612 is higher than the volume concentration of the plurality of particles in the third region 613 on one side of the second region 612 in the X-axis direction. This ensures high insulating performance in the insulating section 61 while suppressing discharges caused by an excessively high volume concentration of the plurality of particles in the second region 612. In the X-ray generator 1A, the circuit unit 62 is embedded in the insulating part 61 so that the entire circuit unit 62 is located in the second region 612. This allows the entire circuit unit 62 to be located in a region of the insulating part 61 that has high insulating performance. Therefore, according to the X-ray generator 1A, the occurrence of discharge in the power supply unit 6 can be effectively suppressed.

[0042] In the X-ray generator 1A, the second volume concentration is 5% or more and 75% or less. This reliably suppresses the occurrence of discharge in the second region 612, which would otherwise be caused by the volume concentration of the plurality of particles becoming too high, while reliably ensuring high insulating performance in the insulating unit 61. Therefore, the entire circuit unit 62 can be reliably positioned in a region of the insulating unit 61 that has high insulating performance. Therefore, according to the X-ray generator 1A, the occurrence of discharge in the power supply unit 6 can be more effectively suppressed.

[0043] In the X-ray generator 1A, the entire circuit unit 62 is located in a region of the second region 612 where the second volume concentration is 20% or more and 60% or less. This makes it possible to more reliably position the entire circuit unit 62 in a region of the insulating unit 61 that has high insulating performance. Therefore, with the X-ray generator 1A, it is possible to more effectively suppress the occurrence of discharge in the power supply unit 6.

[0044] In the X-ray generator 1A, the circuit unit 62 is embedded in the insulating unit 61 so that the second voltage unit 62c is located in the second region 612. According to the X-ray generator 1A, the second voltage unit 62c, which is likely to cause discharge in the circuit unit 62, is located in the second region 612, so that discharge in the power supply unit 6 can be more efficiently suppressed. As a result, the dimensions of the insulating unit 61 can be reduced, and the power supply unit 6 can be made smaller.

[0045] In the X-ray generator 1A, the power supply unit 6 has wiring 63 that electrically connects the second voltage unit 62c and the target 4, the target 4 overlaps with the second region 612 when viewed from the Z-axis direction perpendicular to the X-axis direction, and the circuit unit 62 is embedded in the insulating unit 61 so that the second voltage unit 62c is located between the first voltage unit 62a and the target 4 in the Z-axis direction. This makes it easy to realize a configuration in which the wiring 63, which is prone to generating discharge, passes through the second region 612, thereby more efficiently suppressing the occurrence of discharge within the power supply unit 6.

[0046] In the X-ray generating device 1A, the circuit unit 62 is embedded in the insulating part 61 so that the entire circuit unit 62 is located in the second region 612. This makes it possible to more effectively suppress the occurrence of discharge in the power supply unit 6. [X-ray generator according to the second embodiment]

[0047] 2 and 3, the X-ray generator 1B of the second embodiment differs from the X-ray generator 1A of the first embodiment mainly in that the housing 2 is configured so that the interior of the housing 2 can be opened and closed, and that the circuit unit 62 outputs a second voltage to the electron gun 3. The X-ray generator 1B of the second embodiment will be described below, focusing on the differences from the X-ray generator 1A of the first embodiment.

[0048] The X-ray generating device 1B further includes an exhaust pipe 17 and a power applying unit 18. The power supply unit 6 further includes a wiring (power supply unit) 64 and an electron emission control unit (not shown) electrically connected to the wirings 63 and 64.

[0049] The housing 2 has a fixed part 24, a detachable part 25, a hinge 26, and a cap 27. The fixed part 24 and the detachable part 25 are each formed into a cylindrical shape from a metal material such as stainless steel. The detachable part 25 is attached to the fixed part 24 via the hinge 26. The detachable part 25 defines a passage 25a through which the electron beam passes. An exhaust pipe 17 is attached to the side wall of the fixed part 24. A vacuum pump (not shown) is connected to the exhaust pipe 17. A target 4, which is housed in a cap 27, is attached to the upper end of the detachable part 25. In the X-ray generator 1B, the detachable part 25 is tilted relative to the fixed part 24 to open the interior of the housing 2, allowing the filament and other components of the electron gun 3 to be replaced. A plurality of coils 28 are provided inside the detachable part 25. The multiple coil sections 28 function as electromagnetic deflection lenses to focus the electron beam traveling through the passage 25 a from the electron gun 3 toward the target 4 onto the target 4 .

[0050] The insulating part 61 is composed of a rectangular parallelepiped first part 61f and a cylindrical second part 61g provided on the first part 61f. The fixing part 24 is attached to the upper end of the first part 61f. The second part 61g is located inside the fixing part 24. In the X-ray generator 1B, the second part 61g is included in the second region 612. A portion of each of the power applying parts 7 and 18 is embedded in the second part 61g.

[0051] The electron gun 3 is attached to the tip of the second portion 61g. The electron gun 3 has a grid base 31, screws 32, a heater socket 33, a heater pin (filament) 34, a heater base 35, a grid cap 36, and rings 37 and 38. The grid base 31 is fixed to the power application unit 18 with the screws 32. The heater socket 33 is fitted to the power application unit 7. The heater pin 34 is detachably attached to the heater socket 33. The heater base 35 supports the heater pin 34. The heater pin 34 and the heater base 35 form a cathode electrode. The grid cap 36 covers the heater pin 34 and the heater base 35. The ring 37 is screwed onto the grid base 31 and holds the grid cap 36 in place. This fixes the position of the heater base 35 within the grid cap 36 in cooperation with the ring 38. The electron gun 3 overlaps with the second region 612 when viewed from the Z-axis direction.

[0052] The wiring 63 electrically connects the second voltage section 62c and the electron gun 3 (heater socket 33) via the power application section 7. One end of the wiring 63 is electrically connected to the second voltage section 62c, and the other end of the wiring 63 is connected to the power application section 7. The wiring 64 electrically connects the second voltage section 62c and the electron gun 3 (screw 32) via the power application section 18. One end of the wiring 64 is electrically connected to the second voltage section 62c, and the other end of the wiring 64 is connected to the power application section 18. The wiring 63 is embedded in the insulating section 61 so that the entire wiring 63 is located in the second region 612, and the wiring 64 is embedded in the insulating section 61 so that the entire wiring 64 is located in the second region 612.

[0053] In the X-ray generator 1B configured as described above, the target 4 is set to ground potential, and a negative voltage of, for example, several hundred volts is input as a first voltage from an external power supply via a power supply unit to the first voltage unit 62a. The booster unit 62b boosts the first voltage to a second voltage of, for example, several kV to several hundred kV. The second voltage unit 62c then outputs the second voltage to the electron gun 3 via the wiring 63 and the power application unit 7. The heater pin 34 is heated via the heater socket 33, causing an electron beam to be emitted from the heater pin 34. The electron beam from the electron gun 3 is incident on the target 4, causing X-rays to be generated from the target 4. The X-ray generator 1B is a so-called open transmission type X-ray generator.

[0054] As described above, in the X-ray generator 1B, the housing 2 is configured so that the inside of the housing 2 can be opened and closed. This allows the filament and the like of the electron gun 3 to be replaced. [Variations]

[0055] The present invention is not limited to the above-described embodiments. In the X-ray generator 1A of the first embodiment and the X-ray generator 1B of the second embodiment, the circuit unit 62 is embedded in the insulating unit 61 so that the substrate 621 extends straight along the Z-axis direction. However, the manner in which the circuit unit 62 is embedded in the insulating unit 61 is not limited to this. For example, as shown in FIG. 4 , in the X-ray generator 1A, the circuit unit 62 may be embedded in the insulating unit 61 so that the second voltage unit 62c is located closer to the first region 611 than the first voltage unit 62a. The insulating performance of the region of the second region 612 closer to the first region 611 is higher than the insulating performance of the region of the second region 612 closer to the third region 613. This is because the volume concentration of the plurality of particles in the region of the second region 612 closer to the first region 611 is higher than the volume concentration of the plurality of particles in the region of the second region 612 closer to the third region 613. Therefore, the second voltage section 62c, which is prone to discharge, is located in the second region 612 on the side of the first region 611, which has high insulating performance, and therefore it is possible to more efficiently suppress discharge within the power supply unit 6. As a result, the dimensions of the insulating section 61 can be reduced, and the power supply unit 6 can be made smaller.

[0056] In the X-ray generator 1A of the first embodiment and the X-ray generator 1B of the second embodiment, the circuit unit 62 is embedded in the insulating part 61 so that the entire circuit unit 62 is located in the second region 612. However, the circuit unit 62 may be embedded in the insulating part 61 so that at least a part of the circuit unit 62 is located in the second region 612. For example, the circuit unit 62 may be embedded in the insulating part 61 so that a part of the circuit unit 62 is located in the second region 612 and the other part of the circuit unit 62 is located in the first region 611 or the third region 613. Even in this case, the occurrence of discharge in the power supply unit 6 can be more effectively suppressed than when the entire circuit unit 62 is located in the first region 611 or the third region 613.

[0057] In the X-ray generator 1A of the first embodiment and the X-ray generator 1B of the second embodiment, the second volume concentration is 5% or more and 75% or less, or 20% or more and 60% or less, but the range of the second volume concentration is not limited to these ranges. The second volume concentration may be lower than the first volume concentration and higher than the third volume concentration.

[0058] The X-ray generator 1A of the first embodiment is a sealed reflection type X-ray generator, but the X-ray generator 1A may be a sealed transmission type X-ray generator. The X-ray generator 1B of the second embodiment is an open transmission type X-ray generator, but the X-ray generator 1B may be an open reflection type X-ray generator. [Explanation of symbols]

[0059] 1A, 1B...X-ray generator, 2...housing, 3...electron gun, 4...target, 6...power supply unit, 61...insulating unit, 62...circuit unit, 62a...first voltage unit, 62b...boosting unit, 62c...second voltage unit, 63, 64...wiring (power supply unit), 611...first region, 612...second region, 613...third region.

Claims

1. The housing and an electron gun that emits an electron beam within the housing; a target disposed within the housing and configured to generate X-rays when the electron beam is incident thereon; a power supply unit that generates a voltage to be applied to the electron gun or the target, the power supply unit has an insulating unit and a circuit unit embedded in the insulating unit, the insulating portion includes a base material made of a first insulating material and a plurality of particles made of a second insulating material having higher insulating properties than the first insulating material and dispersed in the base material; the circuit unit includes a first voltage unit to which a first voltage is input from an external device, a boost unit that boosts the first voltage to a second voltage that is the voltage, and a second voltage unit that outputs the second voltage to the electron gun or the target, In the insulating portion, a volume concentration of the plurality of particles in a first region is higher than a volume concentration of the plurality of particles in a second region on one side of the first region in a first direction, and the volume concentration of the plurality of particles in the second region is higher than a volume concentration of the plurality of particles in a third region on the one side of the second region in the first direction; The circuit unit is embedded in the insulating portion so that at least a portion of the circuit unit is located in the second region.

2. The X-ray generating device of claim 1 , wherein the volume concentration of the plurality of particles in the second region is equal to or greater than 5% and equal to or less than 75%.

3. 3. The X-ray generating device according to claim 2, wherein at least the portion of the circuit unit is located in a region of the second region where the volume concentration of the plurality of particles is 20% or more and 60% or less.

4. 4. The X-ray generating device according to claim 1, wherein the circuit section is embedded in the insulating section so that the second voltage section is located in the second region.

5. the power supply unit further includes a power supply unit electrically connecting the second voltage unit and the electron gun or the target, the electron gun or the target overlaps with the second region when viewed from a second direction perpendicular to the first direction, 5. The X-ray generating device according to claim 4, wherein the circuit unit is embedded in the insulating unit such that the second voltage unit is located between the first voltage unit and the electron gun or the target in the second direction.

6. 4. The X-ray generating device according to claim 1, wherein the circuit section is embedded in the insulating section so that the entire circuit section is located in the second region.

7. 7. The X-ray generating device according to claim 6, wherein the circuit section is embedded in the insulating section so that the second voltage section is located on the first region side relative to the first voltage section.

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