TW202111754A - X-ray tube and x-ray generation device - Google Patents

Abstract

This X-ray tube is provided with: an electron gun part which emits electrons; a target which generates X rays; and a vacuum casing part which houses the electron gun part and the target. The vacuum casing part includes a valve part made of an insulating material and coupled to the electron gun part. The X-ray tube is provided with: an inner electrode which is separated from a coupling part of the electron gun part and the valve part and which is disposed opposite to the coupling part; and an outer electrode which is separated from the coupling part and which is disposed opposite to the coupling part. The coupling part is located between the inner electrode and the outer electrode.

Description

X-ray tube and X-ray generator

The invention relates to an X-ray tube and an X-ray generating device.

Patent Documents 1 to 3 describe X-ray tubes that generate X-rays. The X-ray tube includes: an electron gun part which emits electrons; a target which generates X-rays by incident electrons; and a vacuum housing part which holds and houses them. A high voltage is applied between the electron gun part and the target. Therefore, the vacuum housing part is provided with a valve part containing an insulating material. [Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Publication No. 2014-67670 Patent Document 2: Japanese Patent Application Publication No. 2017-22037 Patent Document 3: Japanese Patent No. 6230389

[The problem to be solved by the invention]

Here, in the above-mentioned X-ray tube, the point where the conductor and the two different types of insulators are connected is called the three-contact point. Since the electric field tends to concentrate on the three-contact point, the intensity of the electric field becomes higher and it is easy to produce Discharge. Specifically, in the connection part of the electron gun part and the valve part in the X-ray tube, the electron gun part, the valve part, and the insulator adjacent to the connection part of the electron gun part and the valve part (for example, the vacuum area in the vacuum housing part) Meet. Therefore, the connection part between the electron gun part and the valve part becomes a three-point contact, which is likely to cause electric field concentration.

Therefore, an object of the present invention is to provide an X-ray tube and an X-ray generator capable of suppressing the concentration of an electric field on the connecting portion of the electron gun portion and the valve portion, and suppressing the generation of electric discharge. [Technical means to solve the problem]

An X-ray tube of one aspect of the present invention includes: an electron gun part which emits electrons; a target which is arranged opposite to the electron gun part and generates X-rays by incident electrons; and a vacuum housing part which houses the electron gun part and The target; and the vacuum housing portion has a valve portion that contains an insulating material and is connected to the electron gun portion; and the X-ray tube has: an inner electrode, which is located in the inner area of the vacuum housing portion, to open the connection part of the electron gun portion and the valve portion And arranged opposite to the connecting part; and the outer electrode, which is in the outer region of the vacuum housing part, is separated from the connecting part and arranged opposite to the connecting part; and the connecting part is located between the inner electrode and the outer electrode.

In this X-ray tube, the connection part between the electron gun part and the valve part is located between the inner electrode and the outer electrode. That is, in the X-ray tube, the connection part between the electron gun part and the valve part, which may become a three-contact point, is located between the inner electrode and the outer electrode. Thereby, when power is supplied to the X-ray tube, the electric field is suppressed from being concentrated on the connecting portion (three-point contact) between the inner electrode and the outer electrode. Therefore, the X-ray tube can suppress the concentration of the electric field on the connecting portion of the electron gun portion and the valve portion, and can suppress the generation of discharge.

In the X-ray tube, it is feasible that the connecting portion extends in a ring shape around the exit axis of electrons emitted from the electron gun portion, and the inner electrode and the outer electrode surround the connecting portion from the inner and outer sides of the ring. In this case, the X-ray tube surrounds the connection part with the inner electrode and the outer electrode, which can further suppress the concentration of the electric field in the connection part.

In the X-ray tube, each of the inner electrode and the outer electrode can extend across the connecting part to the electron gun part and the valve part in the opposing direction of the electron gun part and the target. In this case, the X-ray tube can effectively cover the connection part by using the inner electrode and the outer electrode, and the concentration of the electric field in the connection part can be further suppressed.

In the X-ray tube, the outer electrode protrudes across the connecting part in the opposing direction of the electron gun part and the target; the height of the outer electrode protruding from the position of the connecting part in the opposing direction of the electron gun part and the target is set to A, When the distance between the outer electrode and the connecting part is set to B, A≧0.5B can be satisfied. In this case, the X-ray tube uses the outer electrode to effectively prevent the electric field from detouring from the valve portion side toward the connecting portion, and further suppressing the concentration of the electric field in the connecting portion.

In the X-ray tube, the inner electrode protrudes across the connecting part in the direction of the electron gun part and the target; the height of the inner electrode protruding from the position of the connecting part in the direction of the electron gun part and the target is set to C , When the distance between the inner electrode and the connecting part is set to D, it can satisfy C≧0.5D. In this case, the X-ray tube uses the inner electrode to effectively prevent the electric field from detouring from the valve portion side toward the connecting portion, and further suppressing the concentration of the electric field in the connecting portion.

In the X-ray tube, it is feasible that the electron gun part has: an electron gun which emits electrons; and a connecting flange, which includes a conductive material, is fixed to the electron gun and is connected to the valve part; and the connecting flange has a flange facing part, The flange facing part is located in the outer side area of the vacuum housing part, separated from the connecting part and arranged opposite to the connecting part; the outer electrode is constituted by the flange facing part. In this case, the X-ray tube can make the flange facing portion of the connecting flange function as an outer electrode, and the structure can be simplified.

In the X-ray tube, it is feasible that the electron gun part has an electron gun housing part containing a conductive material, and the electron gun housing part has a housing opposite part, which is located in the inner area of the vacuum housing part and is connected to the Partially open and arranged opposite to the connecting part, and the inner electrode is constituted by the opposite part of the housing. In this case, the X-ray tube can make the housing facing portion of the electron gun housing function as an inner electrode, and the structure can be simplified.

In the X-ray tube, it is feasible that the valve part has: an outer tube; an inner tube, which is arranged in the outer tube; and a tube connecting part, which connects one end of the outer tube with an end of the inner tube; and the electron gun part is connected At the other end of the inner tube; the outer electrode is arranged inside the inner tube. In this case, since the connecting part of the X-ray tube is contained in a space surrounded by an outer tube containing an insulating material, it is possible to prevent the connection between the connecting part and the surrounding structure of the X-ray tube (for example, a part of the X-ray generating device). The generation of electric discharge.

In the X-ray tube, it is feasible that the valve part is cylindrical, and the outer electrode accommodates the connection part between the electron gun part and the valve part inside. In this case, the X-ray tube can also suppress the concentration of the electric field in the connecting portion in the cylindrical valve portion that is easy to manufacture, and can suppress the generation of discharge.

An X-ray generating device of another aspect of the present invention includes: an X-ray tube having an electron gun part that emits electrons; a target that is arranged to face the electron gun part and generates X-rays by incident electrons; and a vacuum envelope The body part contains the electron gun part and the target; and the vacuum housing part contains a valve part that contains insulating material and is connected to the electron gun part; the containment part contains at least a part of the X-ray tube; the power feeding part supplies the X-ray tube Electricity; and outer electrodes, which are housed in the accommodating portion and arranged in the outer area of the vacuum housing portion, covering at least a part of the power feeding portion; and the X-ray tube has an inner electrode, the inner electrode in the inner area of the vacuum housing portion , The connecting part of the electron gun part and the valve part is opened and arranged opposite to the connecting part; the outer electrode is separated from the connecting part and arranged opposite to the connecting part; the inner electrode and the outer electrode are each in the opposite direction of the electron gun part and the target , Straddling the connecting part and extending to the electron gun part and the valve part; the connecting part is located between the inner electrode and the outer electrode.

In the X-ray tube of the X-ray generator, the connection part between the electron gun part and the valve part is located between the inner electrode and the outer electrode. That is, in the X-ray tube, the connection part between the electron gun part and the valve part, which may become a three-contact point, is located between the inner electrode and the outer electrode. In addition, each of the inner electrode and the outer electrode straddles the connection part and extends to the electron gun part and the valve part in the opposing direction of the electron gun part and the target. Thereby, when power is supplied to the X-ray tube, the electric field is suppressed from being concentrated on the connecting portion (three-point contact) between the inner electrode and the outer electrode. Therefore, the X-ray generating device can suppress the concentration of the electric field on the connecting portion of the electron gun portion and the valve portion, and can suppress the generation of the discharge of the X-ray tube.

In the X-ray generating device, the outer electrode may have a cylindrical shape that accommodates at least a part of the power feeding part on the inner side. In this case, the outer electrode can have both the function of accommodating and protecting the power feeding part and the function of suppressing the concentration of the electric field in the connecting part.

In the X-ray generating device, it is feasible that the valve part has: an outer tube; an inner tube, which is arranged in the outer tube; and a tube connecting part, which connects one end of the outer tube and one end of the inner tube; an electron gun part Connected to the other end of the inner tube; the outer electrode is arranged inside the inner tube. Since the X-ray generating device is housed in a space surrounded by an outer tube containing an insulating material, the generation of electric discharge between the connecting portion and a part of the X-ray generating device (for example, the receiving section) can be suppressed.

In the X-ray generating device, it is feasible that the valve part has a cylindrical shape, and the outer electrode accommodates the connection part between the electron gun part and the valve part inside. In this case, the X-ray generating device can also suppress the concentration of the electric field in the connecting portion in an X-ray tube with a cylindrical valve portion that is easy to manufacture, and can suppress the generation of electric discharge. [Effects of Invention]

According to the present invention, it is possible to suppress the concentration of the electric field in the connecting portion of the electron gun portion and the valve portion, and to suppress the generation of electric discharge.

Hereinafter, the embodiments of the present invention will be described with reference to the drawings. In addition, in the following description, the same or equivalent elements are given the same reference numerals, and overlapping descriptions are omitted.

(First Embodiment) First, the first embodiment of the X-ray generator will be described. As shown in FIGS. 1 and 2, the X-ray generating device 1 of this embodiment is, for example, a micro-focus X-ray source used for X-ray non-destructive inspection of the internal structure of an object to be inspected. The X-ray generating device 1 includes an X-ray tube 10, a device housing portion 20, and a power supply portion 30.

The X-ray tube 10 includes a vacuum housing part 100, an electron gun part 110, and a target T. The electron gun part 110 emits an electron beam M (electrons) along an emission axis MX. The X-ray tube 10 is a transmissive X-ray tube that is generated by the electron beam M from the electron gun part 110 incident on the target T, and the X-ray XR transmitted through the target T itself is emitted from the X-ray exit window 104. The X-ray tube 10 is a vacuum-sealed X-ray tube having a vacuum housing part 100 having a vacuum inner space R. In addition, in the following, for convenience of description, the side on which the target T is provided for the electron gun portion 110 is referred to as the "front side", and the opposite side is referred to as the "rear side".

The vacuum housing part 100 houses the electron gun part 110 and the target T. The vacuum housing part 100 has a substantially cylindrical shape extending along the tube axis AX of the X-ray tube 10. In addition, in this embodiment, the tube axis AX and the exit axis MX are coaxial. Since the tube axis AX and the exit axis MX are coaxial, they are also collectively referred to as the axis L below. The vacuum housing part 100 includes a head part 101 formed of a metal material (for example, stainless steel, copper, copper alloy, iron alloy, etc.), and a valve part 102 formed of an insulating material (for example, glass, ceramic, etc.). The head 101 is arranged on the front side of the valve 102. The head 101 and the valve 102 are connected to each other by a valve flange 103 made of a metal material such as Kovar.

The electron gun part 110 is connected to the valve part 102. The valve portion 102 has a cylindrical shape extending along the tube axis AX (axis L) of the X-ray tube 10. At the end of the valve portion 102 on the rear side, a cylindrical recess 102w formed by extending along the tube axis AX of the X-ray tube 10 so as to be folded back toward the front side is provided. That is, the valve portion 102 has an outer tube 102a, an inner tube 102b arranged in the outer tube 102a, and an end (one end) on the rear side of the outer tube 102a and an end (one end) on the rear side of the inner tube 102b. Connected tube connecting portion 102c. The outer tube 102a and the inner tube 102b extend along the axis L.

The electron gun 110 is connected to the opening of the front end (the other end) of the inner cylinder 102b so as to seal the opening. That is, the recessed portion 102w extends the creeping distance between the head 101 and the electron gun portion 110 to improve the withstand voltage characteristics, and the electron gun portion 110 is arranged close to the target T due to the internal space R, so that the electron beam M can be easily reduced. Focus.

The head 101 is formed of a metal material and is equivalent to the anode of the X-ray tube 10 in terms of potential. The head 101 has openings at both ends, and has a substantially cylindrical shape extending along the axis L. As shown in FIG. The head 101 communicates with the valve 102 extending along the axis L at the opening on the rear side (refer to FIG. 2).

On the front side of the head 101, the X-ray exit window 104 is fixed so as to cover the opening 101a on the front side of the head 101. The X-ray exit window 104 has a circular plate shape, for example. The X-ray exit window 104 is formed of a material with high X-ray transparency such as beryllium, aluminum, and diamond.

The target T is arranged to face the electron gun part 110. In this embodiment, the target T is opposed to the electron gun section 110 in the axis L direction. That is, the opposing direction of the target T and the electron gun part 110 becomes the axis L direction. The target T is set on the surface on the side of the inner space R of the X-ray exit window 104. In this embodiment, the target T is formed on the surface of the X-ray exit window 104 on the inner space R side. The target T generates X-rays by the incidence of the electron beam M (electrons). As the target T, for example, tungsten, molybdenum, copper, etc. are used.

The electron gun section 110 has an electron gun 120 and a connecting flange 130 for connecting the electron gun 120 to the valve section 102 (the end on the front side of the inner tube 102b). The electron gun 120 emits electrons. The electron gun 120 includes a heater 121, a cathode 122, a first grid electrode 123, a second grid electrode 124, and an electron gun housing portion 125.

The heater 121 is formed by a filament that generates heat by being energized. The cathode 122 becomes an electron emission source that emits electrons by being heated by the heater 121. The first gate electrode 123 controls the amount of electrons emitted from the cathode 122. The second gate electrode 124 has a cylindrical shape that focuses the electrons passing through the first gate electrode 123 toward the target T. The second gate electrode 124 also functions as an extraction electrode for forming an electric field for extracting electrons constituting the electron beam M. The first gate electrode 123 is arranged between the cathode 122 and the second gate electrode 124. The electron gun housing portion 125 includes a conductive material (for example, stainless steel, etc.), and has a cylindrical shape. The electron gun housing 125 accommodates the heater 121, the cathode 122, and the first grid electrode 123. The electron gun housing 125 is connected to the second grid electrode 124 and also serves as a power feeding path to the second grid electrode 124.

The connecting flange 130 is fixed to the electron gun 120 and connected to the valve part 102. The connecting flange 130 seals the opening at the front end of the inner cylinder 102b. The connecting flange 130 includes a flange 131, a shank 132, and a shank flange 133. The flange 131 includes a conductive material (for example, Kovar alloy, etc.) for fixing the electron gun housing 125 of the electron gun 120 and is connected to the front end of the inner cylinder 102b.

In more detail, the flange 131 includes a cylindrical outer flange 131a and an inner flange 131b extending in the axis L direction, and an annular portion 131c. The inner flange 131b is arranged inside the outer flange 131a. The ring portion 131c has a ring shape. The annular portion 131c connects the front end of the outer flange 131a and the front end of the inner flange 131b. The rear end of the outer flange 131a is connected to the front end of the inner tube 102b.

Here, the part of the connecting portion H of the outer flange 131a and the inner tube 102b facing the inner space R is in contact with the vacuum area (insulator) in the inner space R. In addition, the portion of the connecting portion H between the outer flange 131a and the inner cylinder 102b facing the outer side area of the vacuum housing portion 100 is in contact with the insulating oil 22 (insulator) described later. That is, the connecting portion H becomes a three-point contact. In the present embodiment, the connecting portion H (three-point contact) extends in a ring shape around the axis L (exit axis MX).

The handle 132 includes an insulating material (for example, ceramic, glass, etc.), and has a circular plate shape. The shank flange 133 includes a conductive material (for example, Kovar alloy, etc.) and has a cylindrical shape. On the inner side of the shank flange 133, the shank 132 is fixed. The shank flange 133 is embedded and fixed in the inner flange 131 b of the flange 131.

A shank pin S is provided on the shank 132. The shank pin S extends across the inner area and the outer area of the vacuum housing portion 100 and penetrates the shank portion 132. The shank pin S is electrically connected to each component (heater 121 etc.) of the electron gun part 110.

In addition, the X-ray tube 10 includes an inner electrode 140 and an outer electrode 150 surrounding the connecting portion H. The connecting portion H is located between the inner electrode 140 and the outer electrode 150. That is, the three contacts are located between the inner electrode 140 and the outer electrode 150. In other words, the inner electrode 140 and the outer electrode 150 sandwich the three contacts.

The inner electrode 140 is provided in the inner region (in the inner space R) of the vacuum housing part 100. The inner electrode 140 is provided separately from the valve part 102. The inner electrode 140 includes a conductive material (for example, stainless steel, etc.). The inner electrode 140 is separated from the connecting portion H and arranged to face the connecting portion H. In addition, the inner electrode 140 surrounds the connecting portion H extending in a ring shape from the outside when viewed in the direction along the axis L.

In more detail, the inner electrode 140 includes a surrounding portion 141 and a ring portion 142. The surrounding portion 141 has a cylindrical shape and is arranged to extend along the axis L. The enclosing portion 141 encloses the connecting portion H extending in a ring shape from the outside when viewed from the direction along the axis L. The surrounding portion 141 straddles the connecting portion H in the direction of the axis L and extends to the flange 131 of the electron gun portion 110 and the inner tube 102 b of the valve portion 102. That is, the front end of the surrounding portion 141 is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the surrounding portion 141 is located on the rear side of the connecting portion H in the axis L direction.

The ring portion 142 has a ring shape. The ring portion 142 connects the front end of the surrounding portion 141 to the electron gun portion 110. Here, as an example, the ring portion 142 connects the front end of the surrounding portion 141 to the electron gun housing portion 125 of the electron gun portion 110.

In this way, the inner electrode 140 extends from the connection portion with the electron gun portion 110 toward the rear side. When viewed in the direction along the axis L, the inner electrode 140 surrounds the connecting portion H from the outside. That is, the inner electrode 140 straddles the connecting portion H in the direction of the axis L (the opposing direction of the electron gun portion 110 and the target T), and protrudes from the electron gun portion 110 side toward the inner tube 102b side of the valve portion 102 (toward the rear side) . Here, the protrusion height (protrusion length) of the inner electrode 140 (enclosure portion 141) from the position of the connecting portion H in the direction of the axis L is set to C. In addition, let the distance between the inner electrode 140 and the connecting portion H be D. The interval D here is the distance between the inner electrode 140 (the enclosing portion 141) and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending in a ring shape. The protrusion height C and the interval D meet C≧0.5D.

The outer electrode 150 is arranged on the outer side of the vacuum housing part 100 (outside the inner space R), and is arranged inside the inner cylinder 102b. The outer electrode 150 is provided separately from the valve part 102. The outer electrode 150 includes a conductive material (for example, stainless steel, etc.). The outer electrode 150 is separated from the connecting portion H and arranged opposite to the connecting portion H. In addition, the outer electrode 150 surrounds the connecting portion H extending in a ring shape from the inner side when viewed from the direction along the axis L.

In more detail, the outer electrode 150 has a cylindrical shape and is arranged to extend along the axis L. The outer electrode 150 is connected to at least any one of the rear end of the shank flange 133 and the rear end of the inner flange 131 b of the flange 131. The outer electrode 150 straddles the connecting portion H in the direction of the axis L and extends to the flange 131 of the electron gun portion 110 and the inner tube 102 b of the valve portion 102. That is, the front end of the outer electrode 150 is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the outer electrode 150 is located on the rear side of the connecting portion H in the axis L direction.

In this way, the outer electrode 150 extends from the shank flange 133 toward the rear side. When viewed from the direction along the axis L, the outer electrode 150 surrounds the connecting portion H from the inner side. That is, the outer electrode 150 straddles the connecting portion H in the direction of the axis L (the opposing direction of the electron gun portion 110 and the target T) and protrudes from the electron gun portion 110 side toward the inner tube 102b side of the valve portion 102 (toward the rear side) . Here, in the direction of the axis L, the protrusion height (protrusion length) of the outer electrode 150 from the position of the connecting portion H is referred to as A. In addition, the interval between the outer electrode 150 and the connecting portion H is set to B. The interval B here is the distance between the outer electrode 150 and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending in a ring shape. The protrusion height A meets the interval B A≧0.5B.

Here, in this embodiment, the inner electrode 140 and the outer electrode 150 are electrically connected by the electron gun housing 125, the flange 131, and the shank flange 133 that include conductive materials. Therefore, the inner electrode 140, the outer electrode 150, and the flange 131 have the same potential.

The front end portions of the inner electrode 140 and the outer electrode 150 are connected to the electron gun portion 110, respectively. The inner electrode 140 and the outer electrode 150 extend from the electron gun portion 110 toward the rear side, and cover the connecting portion H. The inner electrode 140 and the outer electrode 150 are not in contact with the valve portion 102 (inner cylinder 102b). That is, the rear end portions of the inner electrode 140 and the outer electrode 150 are not in contact with other members. Therefore, the space between the inner electrode 140 and the outer electrode 150 is opened on the rear side. If the protrusion height A of the outer electrode 150 and the protrusion height C of the inner electrode 140 become higher, the distance from the rear side between the inner electrode 140 and the outer electrode 150 to the connecting portion H becomes longer.

The device housing portion 20 includes a cylindrical member (accommodating portion) 21 and a power supply housing 33 as a part of the power supply unit 30. The cylindrical member 21 is formed of metal. The cylindrical member 21 has a cylindrical shape with openings at both ends thereof, and has an internal space 21c. The cylindrical member 21 is inserted into the valve portion 102 of the X-ray tube 10 at the opening 21a on one end side thereof. Thereby, the tube member 21 accommodates at least a part of the X-ray tube 10. More specifically, the cylindrical member 21 accommodates the entire valve portion 102 in this embodiment.

The opening 21a of the cylindrical member 21 is sealed by the head 101 of the X-ray generator 1. In the internal space 21c of the cylindrical member 21, an insulating oil 22 which is a liquid electrical insulating substance is enclosed.

The power supply unit 30 has a function of supplying electric power to the X-ray tube 10. The power supply unit 30 has: a molded insulating block 31 containing a solid insulating material, such as epoxy resin as an insulating resin; a booster 32 molded in the insulating block 31; and a rectangular box-shaped accommodating the same. The power shell 33. The booster 32 adjusts the boosted voltage generated by boosting the introduced voltage introduced from the outside of the X-ray generator 1 as necessary based on various conditions to generate a high-voltage voltage. The insulating block 31 seals the boosting portion 32 with an insulating material (for example, epoxy resin, etc.). To the power supply part 30 (power supply housing 33), the other end side of the cylindrical member 21 is fixed. Thereby, the opening 21b on the other end side of the cylindrical member 21 is sealed, and the insulating oil 22 is sealed in the internal space 21c of the cylindrical member 21.

In addition, the X-ray generator 1 includes a power feeder 40 that electrically connects the booster 32 and the X-ray tube 10. The power feeding unit 40 supplies electric power (high voltage voltage) from the power supply unit 30 to the X-ray tube 10. In more detail, one end of the power feeding unit 40 is connected to the boosting unit 32. The other end of the power feeding portion 40 is inserted into the concave portion 102w of the valve portion 102 of the X-ray tube 10, and the handle portion 132 is electrically connected to the handle pin S protruding from the internal space R of the vacuum. The power feeder 40 has a plurality of wires for supplying electric power.

In addition, in this embodiment, as an example, the target T (anode) is set to a ground potential, and a high voltage voltage of -100 kV is supplied from the power supply unit 30 to the X-ray tube 10 (the electron gun unit 110) via the power feed unit 40. In addition, actually, the voltage adjusted by the high voltage of -100 kV to match the function of each electrode is applied to each electrode of the electron gun section 110. However, for the sake of easy understanding, the voltage applied to the electron gun section 110 is assumed to be described in the following description Is -100 kV.

Next, the electric field generated around the connecting portion H (three-contact point) when power is supplied to the X-ray tube 10 will be described. When power is supplied to the electron gun unit 110, the inner electrode 140, the outer electrode 150, and the flange 131 also become high potentials (-100 kV in this embodiment). As described above, the connecting portion H is positioned in a state of being sandwiched between the inner electrode 140 and the outer electrode 150 having the same potential as each other. Therefore, the electric field concentration in the connecting portion H is suppressed.

The simulation results (equivalence lines) of the electric field generated by the X-ray tube 10 are described. Here, using the model of the X-ray generator shown in FIG. 3, the electron gun 110 was set to a high voltage potential (-100 kV), and the head 101 was set to a ground potential (0 V), and the simulation was performed. As shown in the simulation result shown in FIG. 4, the connecting portion H is sandwiched between the inner electrode 140 and the outer electrode 150, thereby suppressing the detour of the electric field toward the connecting portion H (the detour of the equipotential line), and suppresses the electric field Concentrated in the connecting part H.

In addition, in FIG. 4, the protrusion height A of the outer electrode 150 from the connecting portion H is set to be the same as the distance B between the outer electrode 150 and the connecting portion H, and the protrusion height C of the inner electrode 140 from the connecting portion H is set Set as the simulation result of the case where the distance D between the inner electrode 140 and the connecting portion H is the same.

FIG. 5 shows the simulation result of the case where the protrusion height of the outer electrode 150 and the inner electrode 140 is higher than that shown in FIG. 4. Here, the protrusion height A of the outer electrode 150 from the connecting portion H is set to twice the distance B between the outer electrode 150 and the connecting portion H, and the protrusion height C of the inner electrode 140 from the connecting portion H is set to the inner side The distance D between the electrode 140 and the connecting portion H is twice as large. In this case, as shown in FIG. 5, the detour of the electric field from the rear side of the X-ray tube 10 toward the connecting portion H is further suppressed, and the concentration of the electric field in the connecting portion H is further suppressed. In this way, by increasing the protrusion height A of the outer electrode 150 and the protrusion height C of the inner electrode 140, the concentration of the electric field in the connecting portion H is further suppressed.

Here, for comparison, the case where the connecting portion H is not surrounded by the inner electrode 140 and the outer electrode 150 is also simulated. Here, as shown in FIG. 6, the length of the inner electrode 140 and the outer electrode 150 in the axis L direction is shortened, and the connecting portion H is not sandwiched (not surrounded) by the inner electrode 140 and the outer electrode 150. model. In this case, as shown in FIG. 6, the electric field bypasses the connecting portion H, and the intensity of the electric field at the connecting portion H becomes higher.

As described above, in the X-ray tube 10, the connecting portion H between the electron gun portion 110 and the valve portion 102 (inner tube 102b) is located between the inner electrode 140 and the outer electrode 150. That is, in the X-ray tube 10, the connecting portion H that becomes a three-point contact is located between the inner electrode 140 and the outer electrode 150. Thereby, when power is supplied to the X-ray tube 10, the electric field is suppressed from being concentrated on the connecting portion (three-contact point) between the inner electrode 140 and the outer electrode 150. Therefore, the X-ray tube 10 can suppress the concentration of the electric field on the connecting portion H of the electron gun portion 110 and the valve portion 102, and can suppress the generation of electric discharge.

The inner electrode 140 surrounds the connecting portion H extending in a ring shape from the outer side of the ring shape. The outer electrode 150 surrounds the connecting portion H extending in a ring shape from the inner side of the ring shape. Thereby, the X-ray tube 10 surrounds the connecting portion H from the inner side and the outer side by the inner electrode 140 and the outer electrode 150, and the concentration of the electric field in the connecting portion H can be further suppressed.

Each of the inner electrode 140 and the outer electrode 150 straddles the connecting portion H in the direction of the axis L and extends to the flange 131 of the electron gun portion 110 and the inner tube 102 b of the valve portion 102. In this way, the X-ray tube 10 can effectively cover the connecting portion H by the inner electrode 140 and the outer electrode 150, and the concentration of the electric field in the connecting portion H can be further suppressed.

The protrusion height A of the outer electrode 150 and the distance B between the outer electrode 150 and the connecting portion H satisfy A≧0.5B. Thereby, the X-ray tube 10 can effectively suppress the electric field from the inner tube 102b side of the valve part 102 from the inner tube 102b side of the valve part 102 to the connecting part H by means of the outer electrode 150, and the concentration of the electric field in the connecting part H can be further suppressed.

The protrusion height C of the inner electrode 140 and the distance D between the inner electrode 140 and the connecting portion H satisfy C≧0.5D. Thereby, the X-ray tube 10 can effectively suppress the electric field from the inner tube 102b side of the valve portion 102 from the inner tube 102b side of the valve portion 102 to the connecting portion H by means of the inner electrode 140, and the concentration of the electric field in the connecting portion H can be further suppressed.

The valve part 102 includes an outer tube 102a, an inner tube 102b arranged in the outer tube 102a, and a tube connecting part 102c that connects the outer tube 102a and the inner tube 102b to each other at the rear ends, and the electron gun part 110 is connected to the inner tube 102b At the front end, the outer electrode 150 is arranged inside the inner tube 102b. That is, the X-ray tube 10 includes a valve portion 102 having a shape with one end folded back, and the electron gun portion 110 is fixed in a cylindrical recess 102w. In this case, since the connecting portion H is housed in the space surrounded by the outer tube 102a containing the insulating material, the structure around the connecting portion H and the X-ray tube 10 can be suppressed (for example, as a part of the X-ray generator 1 The generation of electric discharge between the cylindrical members 21).

(The first modification of X-ray tube) Next, a first modification example of the X-ray tube 10 of the first embodiment will be described. Hereinafter, the description will be focused on the differences from the X-ray tube 10 of the first embodiment, and the description of the common configuration will be omitted. In the other modified examples and embodiments described below, only the differences will be described as the center. As shown in FIG. 7, the X-ray tube 10A includes a flange 131A and a shank flange 133A, instead of the flange 131 and the shank flange 133 of the X-ray tube 10 of the first embodiment.

The flange 131A contains a conductive material (for example, Kovar alloy, etc.). The flange 131A includes a cylindrical outer flange 131a and an inner flange (flange facing portion) 131d extending in the axis L direction, and an annular portion 131c. The inner flange 131d extends farther back than the inner flange 131b of the first embodiment. The inner flange 131d is provided separately from the inner tube 102b of the valve portion 102. The inner flange 131 d is located in the outer region of the vacuum housing part 100, and is separated from the connecting part H and arranged opposite to the connecting part H. Specifically, the inner flange 131 d spans the connecting portion H in the axis L direction and extends to the outer flange 131 a and the inner tube 102 b of the valve portion 102. That is, the front end portion of the inner flange 131d is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the inner flange 131d is located on the rear side of the connecting portion H in the axis L direction.

The shank flange (flange facing portion) 133A includes a conductive material (for example, Kovar alloy, etc.) and has a cylindrical shape. On the inner side of the shank flange 133A, the shank 132 is fixed. The shank flange 133A is embedded in the inner flange 131d of the flange 131A. The shank flange 133A extends farther back than the shank flange 133 of the first embodiment. The shank flange 133A is provided separately from the valve portion 102. The shank flange 133A is located in the outer region of the vacuum housing portion 100, and is separated from the connecting portion H and arranged opposite to the connecting portion H. Specifically, the shank flange 133A straddles the connecting portion H in the axis L direction and extends to the outer flange 131 a and the inner tube 102 b of the valve portion 102. In other words, the front end of the shank flange 133A is located on the front side (target T side) of the connecting portion H in the axis L direction. The rear end of the shank flange 133A is located on the rear side of the connecting portion H in the axis L direction.

The X-ray tube 10A includes an outer electrode 150A having the same function as the outer electrode 150 of the first embodiment. The outer electrode 150A is composed of the inner flange 131d of the flange 131A and the shank flange 133A. In addition, the outer electrode 150A may be composed of any one of the inner flange 131d and the shank flange 133A.

As described above, in this modified example, in the X-ray tube 10A, the inner flange 131d and the shank flange 133A can function as the outer electrode 150A, and the outer electrode 150A does not need to be provided as a separate member, and the structure can be simplified.化.

(The second modification of X-ray tube) Next, a second modification example of the X-ray tube 10 of the first embodiment will be described. As shown in FIG. 8, the X-ray tube 10B is a reflective X-ray tube. The X-ray tube 10B is provided with a target support 105 that supports the target T at a position on the front side of the electron gun part 110. The target support 105 supports the target T so that the normal direction of the surface on the electron gun portion 110 side of the target T crosses the axis L direction.

The head 101B of the X-ray tube 10B has an opening 101a at a position different from the front position of the front side of the electron gun 120. The head part 101B is formed of a metal material like the head part 101 of the X-ray tube 10 of the first embodiment, and corresponds to the anode of the X-ray tube 10B in potential. The opening 101a of the head 101B is covered by the X-ray exit window 104. The X-ray tube 10B emits X-rays generated by the electron beam M from the electron gun part 110 entering the target T from the X-ray exit window 104. In this way, even when the reflective X-ray tube 10B is used as the X-ray tube, the same effects as in the first embodiment are exhibited.

(The third modification of X-ray tube) Next, a third modification example of the X-ray tube 10 of the first embodiment will be described. As shown in FIG. 9, the X-ray tube 10C is different from the X-ray tube 10 of the first embodiment in that the valve portion 102C has a cylindrical shape. The X-ray tube 10C includes a vacuum housing portion 100C, an electron gun portion 110C, and a target T.

The vacuum housing part 100C houses the electron gun part 110C and the target T. The vacuum housing portion 100C has a substantially cylindrical outer shape extending along the tube axis AX (axis L). The vacuum housing part 100C includes a head 101C formed of a metal material (for example, stainless steel, copper, copper alloy, iron alloy, etc.), and a valve part 102C formed of an insulating material (for example, glass, ceramic, etc.). The head 101C is formed of a metal material and is equivalent to the anode of the X-ray tube 10C in terms of potential. The head portion 101C and the valve portion 102C are connected to each other by a valve flange 103 made of Kovar alloy or the like.

The valve portion 102C is formed in a cylindrical shape extending along the tube axis AX of the X-ray tube 10C. The electron gun part 110C is connected to the end part on the rear side of the valve part 102C. The opening at the front end of the valve portion 102C is sealed by the head portion 101.

The electron gun part 110C has an electron gun 120 and a connecting flange 130C for connecting the electron gun 120 to the end on the rear side of the valve part 102C. The connecting flange 130C is fixed to the electron gun 120 and is connected to the valve portion 102C. The connecting flange 130C seals the opening at the rear end of the valve portion 102C.

In more detail, the connecting flange 130C includes a flange 131C, a shank 132, and a shank flange 133. The flange 131C includes a conductive material (for example, Kovar alloy, etc.) and has a cylindrical shape. A handle flange 133 and a handle 132 are arranged inside the flange 131C.

The front end of the flange 131C is connected to the rear end of the valve portion 102C. Here, the portion of the connecting portion H of the flange 131C and the valve portion 102C facing the internal space R is in contact with the vacuum region (insulator) in the internal space R. In addition, the portion of the connecting portion H of the flange 131C and the valve portion 102C facing the outer side area of the vacuum housing portion 100C is in contact with the insulating oil 22 (insulator) enclosed in the cylindrical member 21. That is, the connecting portion H becomes a three-point contact. In this modified example, the connecting portion H (three-point contact) extends in a ring shape around the axis L (exit axis MX).

In addition, the X-ray tube 10C includes an inner electrode 140C and an outer electrode 150C surrounding the connection portion H. The connecting portion H is located between the inner electrode 140C and the outer electrode 150C. That is, the three contacts are located between the inner electrode 140C and the outer electrode 150C. In other words, the inner electrode 140C and the outer electrode 150C sandwich the three contacts.

The inner electrode 140C is provided in the inner region (in the inner space R) of the vacuum housing part 100C. The inner electrode 140C is provided separately from the valve portion 102C. The inner electrode 140C includes a conductive material (for example, stainless steel, etc.). The inner electrode 140C is separated from the connecting portion H and arranged to face the connecting portion H. In addition, when viewed in the direction of the axis L, the inner electrode 140C surrounds the connecting portion H extending in a ring shape from the inner side.

In more detail, the inner electrode 140C includes a surrounding portion 141C and an annular portion 142C. The surrounding portion 141C has a cylindrical shape and is arranged to extend along the axis L. The electron gun 120 passes through the inner side of the surrounding portion 141C. When viewed from the direction along the axis L, the surrounding portion 141C surrounds the connecting portion H extending in a ring shape from the inside. The surrounding portion 141C straddles the connecting portion H in the direction of the axis L and extends to the flange 131C and the valve portion 102C of the electron gun portion 110C. That is, the front end of the surrounding portion 141C is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the surrounding portion 141C is located on the rear side of the connecting portion H in the axis L direction.

The ring portion 142C has a ring shape. The annular portion 142C connects the end portion on the rear side of the surrounding portion 141C and the inner peripheral surface of the flange 131C.

In this way, the inner electrode 140C extends toward the front side from the connecting portion of the electron gun portion 110C and the flange 131C. The inner electrode 140C surrounds the connecting portion H from the inner side when viewed from the direction along the axis L. That is, the inner electrode 140C straddles the connecting portion H in the direction of the axis L and protrudes from the flange 131C side of the electron gun portion 110C toward the valve portion 102C side (toward the front side). Here, in the direction of the axis L, the protrusion height (protrusion length) of the inner electrode 140C (enclosing portion 141C) from the position of the connecting portion H is set to C. In addition, let the distance between the inner electrode 140C and the connecting portion H be D. The interval D here is the distance between the inner electrode 140C (the enclosing portion 141C) and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending in a ring shape. The protrusion height C and the interval D meet C≧0.5D.

The outer electrode 150C is provided on the outer side area (outside the internal space R) of the vacuum casing portion 100C, and is provided on the outer side of the vacuum casing portion 100C. The outer electrode 150C is housed in the cylindrical member 21 of the X-ray generator 1. The outer electrode 150C is provided separately from the valve portion 102C. The outer electrode 150C includes a conductive material (for example, stainless steel, etc.). The outer electrode 150C is separated from the connecting portion H and arranged to face the connecting portion H. In addition, the outer electrode 150C surrounds the connecting portion H extending in a ring shape from the outside when viewed from the direction along the axis L.

In more detail, the outer electrode 150C includes a surrounding portion 151C and a ring portion 152C. The surrounding portion 151C has a cylindrical shape and is arranged to extend along the axis L. The vacuum housing part 100C and the electron gun part 110C pass through the inner side of the surrounding part 151C. When viewed from the direction along the axis L, the surrounding portion 151C surrounds the connecting portion H extending in a ring shape from the outside. The surrounding portion 151C straddles the connecting portion H in the direction of the axis L and extends to the flange 131C and the valve portion 102C of the electron gun portion 110C. That is, the front end of the surrounding portion 151C is located on the front side (target T side) of the connection portion H in the axis L direction. The end portion on the rear side of the surrounding portion 151C is located on the rear side of the connecting portion H in the axis L direction.

The ring portion 152C has a ring shape. The ring portion 152C connects the end portion on the rear side of the surrounding portion 151C to the outer peripheral surface of the flange 131C.

In this way, the outer electrode 150C extends toward the front side from the connecting portion of the electron gun portion 110C and the flange 131C. When viewed in the direction along the axis L, the outer electrode 150C surrounds the connecting portion H from the outside. That is, the outer electrode 150C straddles the connecting portion H in the direction of the axis L and protrudes from the flange 131C side of the electron gun portion 110C toward the valve portion 102C side (toward the front side). Here, in the direction of the axis L, the protrusion height (protrusion length) of the outer electrode 150C (enclosing portion 151C) from the position of the connecting portion H is referred to as A. In addition, let the interval between the outer electrode 150C and the connecting portion H be B. The interval B here is the distance between the outer electrode 150C and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending annularly. The protrusion height A meets the interval B A≧0.5B.

Here, in this embodiment, the inner electrode 140C and the outer electrode 150C are electrically connected by a flange 131C containing a conductive material. Therefore, the inner electrode 140C, the outer electrode 150C, and the flange 131C have the same potential.

The rear ends of the inner electrode 140C and the outer electrode 150C are respectively connected to the flange 131C of the electron gun portion 110C. The inner electrode 140C and the outer electrode 150C extend from the flange 131C of the electron gun portion 110C toward the front side, and cover the connecting portion H. The inner electrode 140C and the outer electrode 150C are not in contact with the valve portion 102C. That is, the front end portions of the inner electrode 140C and the outer electrode 150C are not in contact with other members. Therefore, the space between the inner electrode 140C and the outer electrode 150C is opened on the front side. If the protrusion height A of the outer electrode 150C and the protrusion height C of the inner electrode 140C become higher, the distance from the front side through the inner electrode 140C and the outer electrode 150C to the connecting portion H becomes longer.

As described above, in the X-ray tube 10C, the connecting portion H between the electron gun portion 110C (the flange 131C) and the valve portion 102C is located between the inner electrode 140C and the outer electrode 150C. Therefore, various functions and effects similar to those of the X-ray tube 10 of the first embodiment can be exhibited. That is, when the X-ray tube 10C uses the valve portion 102C that is easy to manufacture, and the outer electrode 150C houses the connecting portion H of the electron gun portion 110C (flange 131C) and the valve portion 102C inside, it can also be suppressed The concentration of the electric field in the connecting portion H can suppress the generation of discharge.

(The fourth modification of X-ray tube) Next, a fourth modification example of the X-ray tube 10 of the first embodiment will be described. As shown in FIG. 10, the X-ray tube 10D of the present modification includes an outer electrode 150C of the X-ray tube 10C of the third modification described above and a flange 131C integrally. In more detail, the X-ray tube 10D includes a flange 134 instead of the flange 131C and the outer electrode 150C of the X-ray tube 10C of the third modification.

The flange 134 includes a conductive material (for example, Kovar alloy, etc.). The flange 134 includes a cylindrical portion 134a and a protruding portion 134b. The cylindrical portion 134a and the protruding portion 134b are formed integrally. The cylindrical portion 134a has a cylindrical shape. The cylindrical portion 134a has the same structure as the flange 131C of the X-ray tube 10C of the third modification described above. The valve part 102C is connected to the end part of the front side of the cylindrical part 134a. An inner electrode 140C is connected to the inner peripheral surface of the cylindrical portion 134a.

The protruding portion 134b protrudes from the outer peripheral surface of the front end of the cylindrical portion 134a toward the outside (the direction away from the valve portion 102C) and extends toward the front side. The protruding portion 134b surrounds the connecting portion H of the cylindrical portion 134a and the valve portion 102C from the outside when viewed in the direction along the axis L. In more detail, the protruding portion 134b includes an enclosing portion 134c and an annular portion 134d. The surrounding portion 134c and the ring portion 134d of the protruding portion 134b have the same configuration as the surrounding portion 151C and the ring portion 152C of the outer electrode 150C of the X-ray tube 10C of the third modification. That is, the protruding portion 134b of the flange 134 functions as the outer electrode 150D having the same function as the outer electrode 150C of the X-ray tube 10C of the third modification.

As described above, in this modified example, the X-ray tube 10D can allow the protrusion 134b of the flange 134 to function as the outer electrode 150D, and the outer electrode 150D does not need to be provided as a separate member, and the structure can be simplified.

(The fifth modification of X-ray tube) Next, a fifth modification example of the X-ray tube 10 of the first embodiment will be described. As shown in FIG. 11, the electron gun housing 126 of the electron gun 120E of the X-ray tube 10E of this modification also has the function of the inner electrode 140C of the X-ray tube 10C of the third modification.

In more detail, the X-ray tube 10E includes an electron gun 120E instead of the electron gun 120 of the X-ray tube 10C of the third modification. The electron gun 120E includes an electron gun housing portion 126 instead of the electron gun housing portion 125 of the electron gun 120 of the X-ray tube 10C of the third modification.

The electron gun housing portion 126 includes a conductive material (for example, stainless steel, etc.), and has a substantially cylindrical shape. In more detail, the electron gun housing portion 126 has a housing large-diameter portion 126a, a first annular portion 126b, a housing small-diameter portion (a housing facing portion) 126c, and a second annular portion 126d.

The housing large-diameter portion 126a has a cylindrical shape and is arranged inside the flange 131C. The outer diameter of the large-diameter portion 126a of the housing is substantially equal to the inner diameter of the flange 131C. The outer peripheral surface of the housing large-diameter portion 126a is connected to the inner peripheral surface of the flange 131C. Alternatively, the rear end of the housing large-diameter portion 126a may be connected to the front end of the shank flange 133. The housing small-diameter portion 126c has a cylindrical shape. The outer diameter of the small-diameter portion 126c of the housing is smaller than the outer diameter of the large-diameter portion 126a of the housing. The housing small-diameter portion 126c is arranged at a position on the front side of the housing large-diameter portion 126a. The front end of the housing large-diameter portion 126a and the rear end of the housing small-diameter portion 126c are connected by a first ring-shaped portion 126b. The housing small-diameter portion 126c is separated from the connecting portion H, and is arranged to face the connecting portion H.

In this way, the small-diameter housing portion 126c of the electron gun housing portion 126 becomes the inner space R (inner area) arranged in the vacuum housing portion 100C, and is separated from the connecting portion H and opposed to the housing arranged opposite to the connecting portion H unit. The small diameter portion 126c of the housing surrounds the ring-shaped connecting portion H from the inside when viewed from the direction along the axis L. The front end of the housing small-diameter portion 126c and the rear end of the second gate electrode 124 are connected by a ring-shaped second ring-shaped portion 126d. The electron gun housing part 126 is provided separately from the valve part 102C.

Here, the first annular portion 126b and the small diameter portion 126c of the electron gun housing portion 126 form the same shape as the inner electrode 140C of the X-ray tube 10C of the third modification. That is, the first annular portion 126b and the small-diameter housing portion 126c function as the inner electrode 140E having the same function as the inner electrode 140C of the X-ray tube 10C of the third modification. In other words, the inner electrode 140E is composed of the first annular portion 126b of the electron gun housing portion 126 and the housing small-diameter portion 126c.

As described above, in this modified example, the X-ray tube 10E can allow a part of the electron gun housing portion 126 (the first annular portion 126b and the housing small-diameter portion 126c) to function as the inner electrode 140E. The inner electrode 140E is provided as a separate member, which can simplify the structure.

(The sixth modification of X-ray tube) Next, a sixth modification example of the X-ray tube 10 of the first embodiment will be described. As shown in Fig. 12, the X-ray tube 10F of this modification is a reflective X-ray tube. The X-ray tube 10F is obtained by modifying a part of the configuration of the X-ray tube 10C as the third modification of the transmission type X-ray tube. The X-ray tube 10F is provided with a target support 105 that supports the target T at a position on the front side of the electron gun portion 110C. The target support 105 contains a metal material such as copper. The target support 105 supports the target T so that the normal direction of the surface of the electron gun portion 110C side of the target T crosses the axis L direction.

The head 101F of the X-ray tube 10F has an opening 101a at a position different from the front position of the front side of the electron gun 120. The head 101F is formed of a metal material in the same manner as the head 101 of the X-ray tube 10 of the first embodiment, and corresponds to the anode of the X-ray tube 10F in terms of potential. The opening 101a of the head 101F is covered by the X-ray exit window 104. The X-ray tube 10F emits X-rays generated by the electron beam M from the electron gun portion 110C incident on the target T, and emits the X-rays from the X-ray exit window 104. In this way, even in the case where the reflective X-ray tube 10F is used as the X-ray tube, the same function and effect as the X-ray tube 10C of the third modified example described above are exerted.

(The seventh modification of X-ray tube) Next, a seventh modification example of the X-ray tube 10 of the first embodiment will be described. As shown in FIG. 13, the X-ray tube 10G of this modification example is a reflection type X-ray tube similarly to the X-ray tube 10F of the above-mentioned sixth modification example. However, in the X-ray tube 10G of this modified example, the target support 105 supporting the target T is held by the holding valve portion 107.

In more detail, the vacuum housing portion 100G includes a valve portion 102C, a housing portion 106, and a holding valve portion 107. The housing portion 106 is formed of a metal material (for example, stainless steel, copper, copper alloy, iron alloy, etc.). The housing portion 106 has a cylindrical shape and is arranged to extend in the axis L direction. The housing part 106 is provided with an opening part 106a. The opening 106 a is covered by the X-ray exit window 104. The end portion on the rear side of the housing portion 106 is connected to the end portion on the front side of the valve portion 102C by the valve flange 103.

The holding valve portion 107 is formed of an insulating material (for example, glass, ceramic, etc.). The holding valve portion 107 has a cylindrical shape and is arranged to extend in the axis L direction. The rear end of the holding valve portion 107 is connected to the front end of the housing portion 106 by a connecting portion 108 made of a metal material such as Kovar alloy.

The target support 105 supporting the target T is arranged in the housing part 106 and the holding valve part 107. The target support 105 is connected to the front end of the holding valve portion 107 and extends from the connecting portion with the holding valve portion 107 toward the electron gun portion 110C side. The holding valve portion 107 is connected to the target support 105 by a connecting portion 109 made of a metal material such as Kovar alloy. The X-ray tube 10G emits X-rays generated by the electron beam M from the electron gun portion 110C entering the target T from the X-ray exit window 104.

Here, in the X-ray tube 10G of this modified example, the electron gun portion 110C is supported by an insulator (valve portion 102C), and the target T (target support body 105) is also supported by an insulator (holding valve portion 107). Thereby, voltage can be applied to each of the electron gun portion 110C side and the target T side. That is, for example, when the X-ray tube 10G requires a voltage of 100 kV for X-ray irradiation, the housing portion 106 is set to ground potential, and a voltage of -50 kV is applied to the electron gun portion 110C side, and the target T side Apply a voltage of 50 kV. Thereby, a required potential difference of 100 kV can be obtained between the target T and the electron gun portion 110C. In this way, by dividing the required voltage and applying it to the target T side and the electron gun portion 110C side, the voltage value itself applied to each part can be reduced, and the voltage resistance required for each part can be reduced.

(Second Embodiment) Next, the second embodiment of the X-ray generator will be described. Here, the X-ray tube 10 of the X-ray generator 1 of the above-mentioned first embodiment and the X-ray tubes 10A to 10G of the first to seventh modified examples include outer electrodes 150, 150A, 150C, and 150D as constituent elements. In contrast, in the X-ray generator of this embodiment, in addition to the X-ray tube, an outer electrode is additionally provided.

Specifically, as shown in FIG. 14, the X-ray generator 1A of this embodiment includes an X-ray tube 10H, a power feeder 40H, and an outer electrode 150H. In addition, the X-ray generating device 1A further includes a device housing portion and a power supply portion that are not shown in the drawings, similarly to the device housing portion 20 and the power supply portion 30 of the X-ray generating device 1 of the first embodiment. The device housing portion and power supply portion of the X-ray generating device 1A have the same configuration as the device housing portion 20 and the power supply portion 30 of the X-ray generating device 1 of the first embodiment, and detailed descriptions and drawings are omitted. Show.

Here, the X-ray tube 10H is different from the X-ray tube 10 of the X-ray generator 1 of the first embodiment described above only in that it does not include the outer electrode 150. That is, in the X-ray tube 10H, the configuration other than the outer electrode 150 of the X-ray tube 10 of the first embodiment is the same as the configuration of the X-ray tube 10 of the first embodiment, and the same reference numerals are assigned and detailed descriptions are omitted. In this embodiment, the power feeder 40H supplies electric power (high voltage) from the power supply unit to the X-ray tube 10H. The power feeding unit 40H has the same configuration as the power feeding unit 40 of the X-ray generator 1 of the first embodiment.

The outer electrode 150H is housed in the cylindrical member 21 of the device casing 20. The outer electrode 150H is arranged in an outer area of the vacuum housing part 100. The outer electrode 150H is provided separately from the valve portion 102 of the X-ray tube 10H. The outer electrode 150H includes a conductive material (for example, stainless steel, etc.). The outer electrode 150H is separated from the connecting portion H, and is arranged opposite to the connecting portion H. In addition, the outer electrode 150H surrounds the connecting portion H extending in a ring shape from the inside when viewed from the direction along the axis L. In this embodiment, the outer electrode 150H has a cylindrical shape in which at least a part of the power feeding portion 40H is housed inside. That is, the outer electrode 150H covers at least a part of the power feeder 40H.

In more detail, the outer electrode 150H has a cylindrical shape and is arranged to extend along the axis L. The outer electrode 150H covers the outer peripheral surface of the power feeding portion 40H extending in the direction of the axis L. The outer electrode 150H is arranged inside the inner tube 102b of the valve portion 102. That is, the outer electrode 150H is inserted into the concave portion 102w of the valve portion 102.

As an example, the outer electrode 150H is in contact with at least any one of the rear end of the shank flange 133 and the rear end of the inner flange 131b of the flange 131. Here, the outer electrode 150H is not limited to at least one of the end abutting on the rear side of the shank flange 133 and the end of the inner flange 131b of the flange 131 on the rear side. The outer electrode 150H may be at the same potential as the flange 131 and the inner electrode 140, and may be electrically connected to the flange 131 and the inner electrode 140 via, for example, wiring.

The outer electrode 150H straddles the connecting portion H in the direction of the axis L and extends to the flange 131 of the electron gun portion 110 and the inner tube 102 b of the valve portion 102. That is, the front end of the outer electrode 150H is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the outer electrode 150H is located on the rear side of the connecting portion H in the axis L direction.

In this way, the outer electrode 150H extends from the shank flange 133 toward the rear side. When viewed in the direction along the axis L, the outer electrode 150H surrounds the connecting portion H from the inside. That is, the outer electrode 150H straddles the connecting portion H in the direction of the axis L and protrudes from the electron gun portion 110 side toward the power supply portion 30 side (toward the rear side). Here, in the direction of the axis L, the protrusion height (protrusion length) of the outer electrode 150H from the position of the connecting portion H is referred to as A. In addition, let the interval between the outer electrode 150H and the connecting portion H be B. The interval B here is the distance between the outer electrode 150H and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending annularly. The protrusion height A meets the interval B A≧0.5B.

As described above, the X-ray generator 1A includes an outer electrode 150H that surrounds the connecting portion H from the inside. Therefore, the X-ray generating device 1A, like the X-ray tube 10 of the X-ray generating device 1 of the first embodiment, can suppress the concentration of the electric field in the connecting portion H of the electron gun portion 110 and the valve portion 102, and can suppress the generation of electric discharge. .

The power feeding part 40H is accommodated inside the cylindrical outer electrode 150H. In this case, the outer electrode 150H can hold and protect the power feeding part H and suppress the concentration of the electric field in the connection part H.

The valve part 102 includes an outer tube 102a, an inner tube 102b arranged in the outer tube 102a, and a tube connecting part 102c that connects the outer tube 102a and the inner tube 102b to each other at the rear ends, and the electron gun part 110 is connected to the inner tube 102b At the front end, the outer electrode 150H is arranged inside the inner tube 102b. That is, the X-ray tube 10H of the X-ray generating device 1A includes a valve portion 102 in a shape with one end folded back, and the electron gun portion 110 is fixed in a cylindrical recess 102w. In this case, since the connecting portion H is accommodated in the space surrounded by the outer tube 102a containing insulating material, the generation of electric discharge between the connecting portion H and a part of the X-ray generator 1A (for example, the tube member 21) can be suppressed .

(Variations of the X-ray generator of the second embodiment) Next, a modified example of the X-ray generating apparatus of the second embodiment will be explained. As shown in FIG. 15, the X-ray generator 1B of this modified example includes an X-ray tube 10J, a power feeder 40J, and an outer electrode 150J. In addition, the X-ray generating device 1B further includes a device housing portion and a power supply portion that are not shown in the drawings, similarly to the device housing portion 20 and the power supply portion 30 of the X-ray generating device 1 of the first embodiment. The device housing portion and power supply portion of the X-ray generating device 1B have the same configuration as the device housing portion 20 and the power supply portion 30 of the X-ray generating device 1 of the first embodiment, and detailed descriptions and drawings are omitted. Show.

Here, the X-ray tube 10J is different from the X-ray tube 10C of the third modification described above only in that it does not include the outer electrode 150. That is, in the X-ray tube 10J, the configuration other than the outer electrode 150 of the X-ray tube 10C of the third embodiment is the same as the configuration of the X-ray tube 10C of the third embodiment, and the same reference numerals are assigned and detailed descriptions are omitted. In the present embodiment, the power feeding unit 40J supplies electric power (high voltage) from the power supply unit to the X-ray tube 10J. The power feeding unit 40J has the same structure as the power feeding unit 40 of the X-ray generator 1 of the first embodiment.

The outer electrode 150J is arranged in the outer region of the vacuum housing part 100C. In addition, the outer electrode 150J is housed in a cylindrical member (corresponding to the cylindrical member 21 in FIG. 1) of the device casing. The outer electrode 150J is provided separately from the valve portion 102C of the X-ray tube 10J. The outer electrode 150J includes a conductive material (for example, stainless steel, etc.). The outer electrode 150J is separated from the connecting portion H and arranged opposite to the connecting portion H. In addition, the outer electrode 150J, viewed from the direction along the axis L, surrounds the connecting portion H extending in a ring shape from the outside. In this embodiment, the outer electrode 150J has a cylindrical shape in which at least a part of the power feeding portion 40J (the end connected to the side of the X-ray tube 10J) is housed inside. That is, the outer electrode 150J covers at least a part of the power feeding portion 40J.

In more detail, the outer electrode 150J has a cylindrical shape and is arranged to extend along the axis L. The outer electrode 150J covers the outer peripheral surface of the power feeding portion 40J extending in the direction of the axis L. That is, the outer electrode 150J covers the end of the valve portion 102C on the side where the electron gun portion 110C (flange 131C) is connected from the outer side.

The outer electrode 150J is electrically connected to the flange 131C and the inner electrode 140C through, for example, wiring to have the same potential.

The outer electrode 150J straddles the connecting portion H in the direction of the axis L and extends to the flange 131C and the valve portion 102C of the electron gun portion 110C. That is, the front end of the outer electrode 150J is located on the front side (target T side) of the connection portion H in the axis L direction. The rear end of the outer electrode 150J is located on the rear side of the connecting portion H in the axis L direction.

In this manner, the outer electrode 150J straddles the connecting portion H in the direction of the axis L and protrudes from the flange 131C side of the electron gun portion 110C toward the target T side (toward the front side). Here, in the direction of the axis L, the protrusion height (protrusion length) of the outer electrode 150J from the position of the connecting portion H is referred to as A. In addition, let the interval between the outer electrode 150J and the connecting portion H be B. The interval B here is the distance between the outer electrode 150J and the connecting portion H in the radial direction (the direction perpendicular to the axis L) of the connecting portion H extending in a ring shape. The protrusion height A meets the interval B A≧0.5B.

As described above, the X-ray generator 1B includes an outer electrode 150J that surrounds the connecting portion H from the inside. Therefore, the X-ray generator 1B, like the X-ray tube 10 of the X-ray generator 1 of the first embodiment, can suppress the concentration of the electric field in the connecting portion H of the electron gun portion 110C and the valve portion 102C, and can suppress the generation of discharge. . In addition, when the X-ray generator 1B uses the valve portion 102C that is easy to manufacture, and the outer electrode 150J houses the connecting portion H of the electron gun portion 110C (flange 131C) and the valve portion 102C inside, it can also be suppressed The concentration of the electric field in the connecting portion H can suppress the generation of discharge.

In the foregoing, various embodiments and modified examples of the present invention have been described, but the present invention is not limited to the above-mentioned embodiments and modified examples. For example, at least a part of the various embodiments and various modifications described above can be combined arbitrarily.

1,1A,1B: X-ray generator 10,10A～10H,10J: X-ray tube 20: Device housing 21: Cylinder member (receiving part) 21a, 21b, 101a: opening 21c: internal space 22: insulating oil 30: Power supply department 31: Insulating block 32: Boost 33: power shell 40, 40H, 40J: power feeder 100, 100C, 100G: Vacuum shell part 101, 101B, 101C, 101F: head 102, 102C: Valve section 102a: outer cylinder 102b: inner cylinder 102c: Cylinder connection part 102w: recess 103: Valve flange 104: X-ray exit window 105: target support 106: Shell 106a: opening 107: Keep the valve part 108, 109: connecting part 110, 110C: electron gun department 120, 120E: electron gun 121: heater 122: cathode 123: The first gate electrode 124: 2nd gate electrode 125, 126: Electron gun housing 126a: Large diameter part of the shell 126b: The first ring part 126c: Small diameter part of the shell (opposite part of the shell) 126d: 2nd ring part 130, 130C: connecting flange 131, 131A, 131C, 134: flange 131a: Outer flange 131b: inner flange 131c, 134d, 142, 142C, 152C: ring part 131d: Inner flange (opposite part of flange) 132: handle 133: Shank flange (opposite part of flange) 133A: Shank flange 134a: Tube 134b: protrusion 134c, 141, 141C, 151C: Surrounding part 140, 140C, 140E: inner electrode 150, 150A, 150C, 150D, 150H, 150J: outer electrode A: Protruding height AX: tube axis B: interval C: Protruding height D: interval H: connecting part L: axis M: electron beam MX: exit axis R: Internal space S: Shank pin T: target XR: X-ray

Fig. 1 is a longitudinal cross-sectional view showing the X-ray generator of the first embodiment. Fig. 2 is a cross-sectional view of the X-ray tube of Fig. 1 cut in the longitudinal direction. Fig. 3 is a cross-sectional view showing the model of the X-ray generating device used in the simulation of the electric field. Fig. 4 is a graph showing the simulation result (equipment line) of the electric field generated by the X-ray tube. Figure 5 is a graph showing the simulation results (equipment lines) of the electric field generated by the X-ray tube. Fig. 6 is a graph showing the simulation result (equipment line) of the electric field generated by the X-ray tube. Fig. 7 is a cross-sectional view of the X-ray tube of the first modified example cut in the longitudinal direction. Fig. 8 is a cross-sectional view of the X-ray tube of the second modification example cut in the longitudinal direction. Fig. 9 is a cross-sectional view of the X-ray tube of the third modification example cut in the longitudinal direction. Fig. 10 is a cross-sectional view of the X-ray tube of the fourth modified example cut in the longitudinal direction. Fig. 11 is a cross-sectional view of the X-ray tube of the fifth modified example cut in the longitudinal direction. Fig. 12 is a cross-sectional view of the X-ray tube of the sixth modified example cut in the longitudinal direction. Fig. 13 is a cross-sectional view of the X-ray tube of the seventh modification in the longitudinal direction. Fig. 14 is a cross-sectional view of the X-ray tube of the X-ray generator of the second embodiment cut in the longitudinal direction. Fig. 15 is a cross-sectional view of the X-ray tube of the X-ray generator according to the modified example of the second embodiment cut in the longitudinal direction.

10: X-ray tube

100: Vacuum shell part

101: head

101a: opening

102: Valve Department

102a: outer cylinder

102b: inner cylinder

102c: Cylinder connection part

102w: recess

103: Valve flange

104: X-ray exit window

110: Electron Gun Department

120: electron gun

121: heater

122: cathode

123: The first gate electrode

124: 2nd gate electrode

125: Electron gun housing

130: connecting flange

131: Flange

131a: Outer flange

131b: inner flange

131c, 142: Ring part

132: handle

133: Shank flange (opposite part of flange)

140: inner electrode

141: Surrounding part

150: Outer electrode

A: Protruding height

AX: tube axis

B: interval

C: Protruding height

D: interval

H: connecting part

L: axis

M: electron beam

MX: exit axis

R: Internal space

S: Shank pin

T: target

XR: X-ray

Claims (13)

An X-ray tube, which has: An electron gun part which emits electrons; a target which is arranged to be opposed to the electron gun part and generates X-rays by incident the electrons; and a vacuum housing part which houses the electron gun part and the target; and the vacuum housing part It has a valve part that includes an insulating material and is connected to the aforementioned electron gun part; and the X-ray tube has: An inner electrode, which is located in the inner region of the vacuum housing part, is separated from the connection part of the electron gun part and the valve part and is arranged opposite to the connection part; and The outer electrode, which is located in the outer region of the vacuum housing part, is separated from the connecting part and arranged opposite to the connecting part; and The connecting portion is located between the inner electrode and the outer electrode. The X-ray tube of claim 1, wherein the connecting portion extends in a ring shape around the exit axis of the electron gun portion emitting the electrons; and The inner electrode and the outer electrode surround the connecting portion from the inner and outer sides of the ring. The X-ray tube of claim 1 or 2, wherein each of the inner electrode and the outer electrode extends across the connecting portion to the electron gun portion and the valve portion in the opposing direction of the electron gun portion and the target. The X-ray tube of claim 3, wherein the outer electrode protrudes across the connecting portion in the opposing direction of the electron gun portion and the target; and When the height of the outer electrode protruding from the position of the connecting portion in the opposing direction of the electron gun portion and the target is set to A, and the distance between the outer electrode and the connecting portion is set to B, the following is satisfied: A≧0.5B. The X-ray tube of claim 3 or 4, wherein the inner electrode protrudes across the connecting portion in the opposing direction of the electron gun portion and the target; and When the height of the inner electrode protruding from the position of the connecting portion in the opposing direction of the electron gun portion and the target is set to C, and the distance between the inner electrode and the connecting portion is set to D, the following is satisfied: C≧0.5D. Such as the X-ray tube of any one of Claims 1 to 5, wherein the aforementioned electron gun part has: An electron gun, which emits the aforementioned electrons; and A connecting flange, which includes a conductive material, is fixed to the electron gun and is connected to the valve part; and The connecting flange has a flange facing portion, the flange facing portion is located in the outer region of the vacuum housing portion, separated from the connecting portion and arranged opposite to the connecting portion; The outer electrode is composed of the flange facing portion. The X-ray tube of any one of claims 1 to 6, wherein the aforementioned electron gun part has an electron gun housing part containing a conductive material; and The electron gun housing portion has a housing opposing portion, the housing opposing portion is located in the inner region of the vacuum housing portion, separated from the connecting portion and disposed opposite to the connecting portion; The inner electrode is constituted by the housing facing portion. Such as the X-ray tube of any one of claims 1 to 7, wherein the aforementioned valve part has: Outer tube The inner cylinder, which is arranged in the aforementioned outer cylinder; and A tube connecting portion, which connects one end of the outer tube and one end of the inner tube; and The aforementioned electron gun part is connected to the other end of the aforementioned inner cylinder; The outer electrode is arranged inside the inner cylinder. The X-ray tube according to any one of claims 1 to 7, wherein the aforementioned valve part is in a cylindrical shape; and The outer electrode accommodates the connecting part of the electron gun part and the valve part inside. An X-ray generating device, which is provided with: An X-ray tube having: an electron gun part which emits electrons; a target which is arranged opposite to the electron gun part and generates X-rays by incident the electrons; and a vacuum housing part which houses the electron gun part and the target And the aforementioned vacuum housing portion includes a valve portion that contains an insulating material and is connected to the aforementioned electron gun portion; The receiving part, which receives at least a part of the aforementioned X-ray tube; The power feeder, which supplies power to the aforementioned X-ray tube; and An outer electrode, which is received in the receiving portion and arranged in the outer region of the vacuum housing portion, and covers at least a part of the power feeding portion; and The X-ray tube has an inner electrode, and the inner electrode is located in the inner region of the vacuum housing portion, which is open to the connecting portion of the electron gun portion and the valve portion and is arranged opposite to the connecting portion; The outer electrode is separated from the connecting part and arranged opposite to the connecting part; Each of the inner electrode and the outer electrode extends across the connecting portion in the opposing direction of the electron gun portion and the target to the electron gun portion and the valve portion; The connecting portion is located between the inner electrode and the outer electrode. The X-ray generating device of claim 10, wherein the outer electrode has a cylindrical shape in which at least a part of the power feeding part is housed inside. Such as the X-ray generating device of claim 11, wherein the aforementioned valve part has: Outer tube The inner cylinder, which is arranged in the aforementioned outer cylinder; and A tube connecting portion, which connects one end of the outer tube and one end of the inner tube; and The aforementioned electron gun part is connected to the other end of the aforementioned inner cylinder; The outer electrode is arranged inside the inner cylinder. Such as the X-ray generating device of claim 11, wherein the aforementioned valve part is in a cylindrical shape; and The outer electrode accommodates the connecting part of the electron gun part and the valve part inside.

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