X-ray tube device

Abstract

To provide an X-ray tube device that can extend the product lifespan. [Solution] The X-ray tube apparatus 1 comprises a cathode 15, an anode target 13, a first tube section (7a and 14) having one end 7ae and the other end 14e, a second tube section (7b) having a first end 7be1 and a second end 7be2, and a protective film PR made of hard gold that covers the inner surfaces (S1 and S2) of the first tube section. The hard gold is made of a material in which indium is added to gold. The concentration of indium in the hard gold is in the range of 4 to 8 wt%.

Description

Technical Field

[0001] Embodiments of the present invention relate to an X-ray tube device.

Background Art

[0002] An X-ray tube device used for fluorescent X-ray analysis includes a cathode, an anode target, a cooling pipe, a water conduit pipe, and a joint connection part (hereinafter referred to as a joint) that connects the water conduit pipe and the cooling pipe. The X-ray tube device has a coolant flow path for cooling an anode target composed of a cooling pipe, a water conduit pipe, a joint, and other structures. The anode target is joined to a predetermined position outside the structures that form this flow path. The water conduit pipe and the cooling pipe are each connected to the joint. The water conduit pipe is composed of, for example, an inner pipe provided inside and an outer pipe provided outside. The tip nozzle part of the inner pipe is installed so as to discharge the coolant in the direction where the anode target is installed. In this case, the cooling pipe is composed of a first cooling pipe connected to the inner pipe via the joint and a second cooling pipe connected to the outer pipe via the joint. In this X-ray tube device, the coolant is sent from the first cooling pipe through the joint to the inner pipe, and is discharged from the second cooling pipe through the joint through the flow path between the inner pipe and the outer pipe.

[0003] In an X-ray tube device, when electrons emitted from the cathode strike the anode target, the anode target and its peripheral portion become hot. The anode target and its peripheral portion are cooled by the coolant flowing through a flow path configured nearby. In the wall surface of the flow path near the portion where the anode target is installed within the flow path through which the coolant flows, subcooled boiling of the coolant, cavitation in the flow of the coolant, etc. may occur. Due to these subcooled boiling, cavitation, etc., bubbles are generated near the flow path near the portion where the anode target is installed, that is, near the tip nozzle part of the inner pipe.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-162974 [Patent Document 2] Japanese Patent Publication No. 2021-044155 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] This embodiment provides an X-ray tube apparatus that can extend the product lifespan. [Means for solving the problem]

[0006] An X-ray tube apparatus according to one embodiment is: A cathode that emits electrons, An anode target that generates X-rays when electrons emitted from the cathode strike it, A first pipe section having one end and the other end including a closed bottom to which the anode target is joined, A second pipe section having a first end located inside the first pipe section and having an intake port for taking in coolant, and a second end facing the bottom section and having an outlet port for discharging the coolant to the bottom section, and together with the first pipe section forming a flow path for the coolant, The first pipe section comprises a protective film made of hard gold that covers the inner surface, The aforementioned hard gold is formed from a material in which indium is added to gold. The concentration of indium in the hard gold is in the range of 4 to 8 wt%. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a cross-sectional view showing an X-ray tube apparatus according to one embodiment; Figure 1(a) is a cross-sectional view showing the entire X-ray tube apparatus; Figure 1(b) is an enlarged partial cross-sectional view of a part of the X-ray tube apparatus; and Figure 1(c) is an enlarged partial cross-sectional view of another part of the X-ray tube apparatus. [Figure 2] Figure 2 is a graph showing the change in hardness and thermal conductivity of the protective film as a function of the indium content in the protective film. [Figure 3] Figure 3 is a partially cross-sectional view showing an enlarged portion of the X-ray tube apparatus according to a modified example. [Modes for carrying out the invention]

[0008] (One embodiment) The following describes an X-ray tube apparatus 1 according to one embodiment with reference to the drawings. Figure 1 is a cross-sectional view showing the X-ray tube apparatus 1 according to one embodiment. Figure 1(a) is a cross-sectional view showing the entire X-ray tube apparatus 1, Figure 1(b) is an enlarged partial cross-sectional view of a part of the X-ray tube apparatus 1, and Figure 1(c) is an enlarged partial cross-sectional view of another part of the X-ray tube apparatus 1. Figure 1(a) shows a cross-section of a part of the X-ray tube apparatus 1 with the tube axis TA as the center. Hereinafter, the direction parallel to the tube axis TA will be referred to as the axial direction da. In the axial direction da, the X-ray tube 2 side will be referred to as the downward direction (downward side), and the direction opposite to the downward direction will be referred to as the upward direction (upward side). The direction perpendicular to the tube axis TA will be referred to as the radial direction.

[0009] As shown in Figure 1, the X-ray tube apparatus 1 comprises an X-ray tube 2 and a tube container 3 containing the X-ray tube 2. Furthermore, the X-ray tube apparatus 1 comprises a high-voltage receptacle 4 for inserting and connecting a high-voltage cable, a cooling pipe 5, a joint connection part (hereinafter simply referred to as a joint) 6, a water supply pipe 7, a conductor spring 8 that electrically connects the high-voltage receptacle 4 and the water supply pipe 7, a cylindrical insulating cylinder 9 provided on the outside of the high-voltage receptacle 4, and a bellows 11 that separates the empty basin 10, which is an expansion / contraction space, from the internal space 22.

[0010] The high-voltage receptacle 4 is formed in a bottomed cylindrical shape with an open upper end and a closed lower end for connecting high-voltage cables. The high-voltage receptacle 4 is liquid-tightly installed on the upper side of the tube container 3, which will be described later, with the tube axis TA as its central axis. The high-voltage receptacle 4 is equipped with a connection terminal 12 that penetrates from the inside to the bottom on the outside. The connection terminal 12 includes a bushing for an external circuit that is inserted into the high-voltage receptacle 4, and the terminal itself. The connection terminal 12 is connected to the joint 6 via a conductor spring 8.

[0011] The insulating cylinder 9 is formed from an insulator with a roughly cylindrical shape. The insulating cylinder 9 is structured to allow insulating oil to flow through it, although this is not shown in the diagram. For example, the upper end of the insulating cylinder 9 is fixed to the inside of the tube container 3.

[0012] The cooling pipe 5 is a conduit for carrying a coolant, such as pure water as an aqueous coolant. The cooling pipe 5 is spirally arranged between the high-voltage receptacle 4 and the insulating cylinder 9. The cooling pipe 5 consists of a first cooling pipe 5b equipped with a water inlet 5a to which the coolant is supplied, and a second cooling pipe 5c equipped with an outlet 5d from which the coolant is discharged. The water inlet 5a of the first cooling pipe 5b is connected to a circulating cooling device or the like (not shown), which is the source of the coolant, and the end opposite to the water inlet 5a is connected to a joint 6. On the other hand, the outlet 5d of the second cooling pipe 5c is connected to a circulating cooling device or the like (not shown), and the end opposite to the outlet 5d is connected to a joint 6. Note that the cooling pipe 5 does not necessarily have to be spirally arranged.

[0013] The joint 6 is located in the center of the X-ray tube apparatus 1, for example, on the tube axis TA, and connects the cooling pipe 5 and the water supply pipe 7. The joint 6 has a main body 6a with three holes: a first passage 6p1, a second passage 6p2 formed substantially parallel to the first passage 6p1, and a third passage 6p3 formed perpendicular to the first passage 6p1 and the second passage 6p2.

[0014] For example, as shown in FIG. 1(b), the first passage 6p1 is formed at the upper part of the main body 6a, communicating from the side surface portion (outer peripheral portion) to the third passage 6p3 substantially perpendicular to the pipe axis TA. Similarly, the second passage 6p2 is formed at a lower position than the first passage 6p1 of the main body 6a, communicating from the side surface portion to the third passage 6p3 substantially perpendicular to the pipe axis TA. That is, the first and second passages 6p1 and 6p2 each open in a direction perpendicular to the pipe axis TA on the side surface portion of the main body 6a. Further, the first cooling pipe 5b is liquid-tightly connected to the first passage 6p1, and the second cooling pipe 5c is liquid-tightly connected to the second passage 6p2.

[0015] The third passage 6p3 is formed to communicate from the lower end portion of the main body 6a to the first passage 6p1 along the pipe axis TA, and has a step from the portion connected to the second passage 6p2 to the portion connected to the first passage 6p1. That is, the third passage 6p3 opens downward along the pipe axis TA, and the hole diameter of the portion connected to the first passage 6p1 is formed smaller than the hole diameter of the portion connected to the second passage 6p2. Hereinafter, in the third passage 6p3, the portion with a small hole diameter connected to the first passage 6p1 is referred to as a small-diameter portion, and the portion with a large hole diameter connected to the second passage 6p2 is referred to as a large-diameter portion.

[0016] The water guide pipe 7 includes an outer pipe 7a formed in a cylindrical shape and an inner pipe 7b formed in a cylindrical shape provided inside the outer pipe 7a. Further, the water guide pipe 7 is provided with an elastic member 23 and a support member 25 inside. The water guide pipe (pipe portion) 7 is provided to extend along the axial direction da, for example, along the pipe axis TA, and is connected to the lower part of the joint 6.

[0017] The outer pipe 7a is liquid-tightly joined to each of the lower part of the main body 6a of the joint 6 and the upper part of the anode block 14 described later. The inner diameter of the outer pipe 7a is formed to be substantially the same as the diameter of the small-diameter portion of the third passage 6p3.

[0018] The inner pipe 7b is formed with an outer diameter smaller than the inner diameter of the outer pipe 7a. The inner pipe 7b extends along the pipe axis TA, with its upper end fitted into the small-diameter portion of the third passage 6p3, its middle portion supported by the support member 25, and its lower end provided with a tip nozzle portion 24. The outer diameter of the inner pipe 7b is substantially the same as the hole diameter of the first passage 6p1, and there is a fitting clearance with a predetermined tolerance between the inner pipe 7b and the first passage 6p1.

[0019] The shape of the elastic member 23 is, for example, an O-ring shape or a pipe shape. The cross-sectional shape of the elastic member 23 may be circular or square. The elastic member 23 is formed of a resinous rubber member. The elastic member 23 is provided at the stepped portion of the third passage 6p3 between the outer peripheral portion near the fitting portion of the inner pipe 7b and the large-diameter portion of the third passage 6p3. The thickness of the elastic member 23 is substantially the same as or larger than the width between the outer diameter of the inner pipe 7b and the diameter of the large-diameter portion of the third passage 6p3. Also, the elastic member 23 may be provided at least partially between the inner pipe 7b and the third passage 6p3 in the vicinity of the fitting portion of the inner pipe 7b.

[0020] The outer pipe 7a and the anode block 14 function as a first pipe portion and extend in the axial direction da. The first pipe portion has one end portion 7ae on the joint 6 side and the other end portion 14e including a bottom portion 14b to which the closed anode target 13 is joined. Note that the anode target 13 is located outside the anode block 14.

[0021] The inner pipe 7b functions as a second pipe portion and is located inside the outer pipe 7a and the anode block 14. The inner pipe 7b has a first end portion 7be1 and a second end portion 7be2, and together with the first pipe portion (outer pipe 7a and anode block 14), forms a coolant flow path. An intake port IL for taking in coolant is formed at the first end portion 7be1. The second end portion 7be2 corresponds to the tip nozzle portion 24 and faces the bottom portion 14b. A discharge port OL for discharging the coolant to the bottom portion 14b is formed at the second end portion 7be2.

[0022] As shown in Figure 1(c), the anode block 14 is made of copper, which has high thermal conductivity. The protective film PR covers the inner surface of the anode block 14 (first tube section). The inner surface of the anode block 14 has a bottom surface S1 and an inner circumferential surface S2. The bottom surface S1 is the surface of the bottom 14b opposite to the side facing the anode target 13 in the axial direction da. The inner circumferential surface S2 is the surface radially opposite to the tip nozzle section 24 and is provided continuously from the bottom surface S1.

[0023] The protective film PR covers at least the bottom surface S1 of the inner surface of the anode block 14. In this embodiment, the protective film PR continuously covers from the bottom surface S1 to the inner circumferential surface S2. The protective film PR is formed by a plating method and is hard gold plating.

[0024] The protective film PR is made of hard gold. Hard gold uses indium (In) as an additive. In other words, hard gold is made of gold with indium added. The concentration of indium in hard gold is in the range of 4 to 8 wt%. When the indium concentration is 8 wt%, hard gold contains 92 wt% gold. However, in reality, hard gold will contain impurities. The maximum permissible impurity concentration is 0.1 wt%.

[0025] For example, suppose hard gold contains less than 0.1 wt% of impurities. If the indium concentration is 4 wt%, the hard gold contains 95.9 wt% or more and less than 96 wt% of gold. If the indium concentration is 8 wt%, the hard gold contains 91.9 wt% or more and less than 92 wt% of gold.

[0026] Here, let T1 be the thickness of the protective film PR in the region facing the bottom surface S1, and T2 be the thickness of the protective film PR in the region facing the inner circumferential surface S2. In this embodiment, the thickness T1 is in the range of 15 to 25 μm, and the thickness T2 is in the range of 25 to 35 μm. The thickness T2 tends to be larger than the thickness T1, but the relationship between the thicknesses T1 and T2 is not limited to the above relationship. For example, the thickness T1 may be larger than the thickness T2.

[0027] The protective film PR is provided to prevent corrosion and erosion of the anode block 14 by the coolant. The protective film PR, made of hard gold, has high thermal conductivity and high hardness. Therefore, the protective film PR made of hard gold can suppress or prevent a decrease in the cooling efficiency of the anode block 14 and the anode target 13, and has excellent resistance to corrosion and erosion.

[0028] As shown in Figure 1, the X-ray tube 2 comprises an anode target (anode) 13, an anode block 14, an electron-emitting cathode 15, a Wehnert electrode 16, a first vacuum enclosure 17, and a second vacuum enclosure 18. When a high-voltage cable is connected to the high-voltage receptacle 4, a high voltage (tube voltage) is applied between the anode target 13 and the cathode 15, which will be described later.

[0029] The anode block 14 is formed in a bottomed cylindrical shape with the pipe axis TA as its central axis. The lower end of the outer pipe 7a is fixed to the opening side of the anode block 14. Inside the anode block 14, the tip nozzle portion 24 of the inner pipe 7b is positioned. Coolant is discharged from this tip nozzle portion 24 toward the bottom 14b of the anode block 14 (or toward the installation direction of the anode target 13).

[0030] In the X-ray tube apparatus 1, the aforementioned joint 6, water conduit pipe 7, and anode block 14 are assembled to form a flow path for the coolant. Although the joint 6, water conduit pipe 7, and anode block 14 are described as separate components, they may all be formed as a single unit or partially as a single unit, as long as they form a flow path for the coolant. The coolant circulates through the flow path formed by the joint 6, water conduit pipe 7, and anode block 14, and through the cooling pipe 5, thereby cooling the insulating oil and anode target 13, etc., that are filled in the internal space 22, which will be described later.

[0031] The anode target 13 is joined to the bottom 14b of the anode block 14. X-rays are generated when electrons strike the anode target 13. At this time, the temperature of the anode target 13 rises due to the electron strike, but it is cooled by the coolant flowing through the internal channels of the anode block 14. Relatively, a positive voltage is applied to the anode target 13 and a negative voltage is applied to the cathode 15. For example, the cathode 15 is electrically grounded.

[0032] The cathode 15 is formed from a ring-shaped filament and is positioned radially outward from the anode target 13 (or anode block 14) at a predetermined distance. Electrons emitted from the cathode 15 pass over the lower end of the Wehnelt electrode 16 (described later) and collide with the anode target 13.

[0033] The Wehnelt electrode 16 is formed in a circular shape and is positioned between the anode target 13 and the cathode 15. The Wehnelt electrode 16 focuses electrons emitted from the cathode 15 onto the anode target 13.

[0034] The first vacuum enclosure 17 consists of an inner cylinder and an outer cylinder. The upper ends of the inner cylinder and the outer cylinder of the first vacuum enclosure 17 are joined to each other. The inner cylinder and the outer cylinder are each substantially cylindrical in shape and are made of, for example, glass or ceramic material. The lower end of the inner cylinder of the first vacuum enclosure 17 is vacuum-sealed to the anode block 14, and the lower end of the outer cylinder is vacuum-sealed to the wall of the X-ray tube 2 as part of the wall surface of the X-ray tube 2.

[0035] The second vacuum enclosure 18 is formed in a substantially cylindrical shape with a bottom. The upper end of the second vacuum enclosure 18 is vacuum-sealed to the wall of the X-ray tube 2 as part of the wall surface of the X-ray tube 2. The second vacuum enclosure 18 is electrically grounded together with the tube container 3, which will be described later. An X-ray transmission window (window section) 19 is vacuum-sealed to an opening that penetrates near the center of the bottom of the second vacuum enclosure 18.

[0036] The X-ray transmission window 19 transmits X-rays generated from the anode target 13 when electrons collide, and emits the X-rays to the outside through the X-ray tube apparatus 1. The X-ray transmission window 19 is formed of an X-ray-transmitting material, such as a beryllium plate. The X-ray tube 2 is also provided with a first protrusion 20a and a second protrusion 20b that project radially outward from a part of its outer wall.

[0037] The tube container 3 is a sealed container that houses the various parts of the X-ray tube apparatus 1. The tube container 3 is formed in a substantially cylindrical shape with the tube axis TA as its central axis. The tube container 3 is made of, for example, a metal material. Furthermore, the tube container 3 has a lead plate 21 lining its inner wall. The internal space 22 inside the tube container 3 (lead plate 21) is filled with insulating oil. Here, the internal space 22 is, for example, the space inside the tube container 3, outside the X-ray tube 2 and the high-voltage receptacle 4, and excluding the empty basin 10.

[0038] The bellows 11 is provided in a predetermined portion on the lower side of the tube container 3 to separate the internal space 22 from the empty basin 10. One end of the bellows 11 is fixed to the first protrusion 20a, and the other end is fixed to the second protrusion 20b. The bellows 11 is made of a resinous elastic material and absorbs the expansion and contraction of the insulating oil by expanding and contracting in the empty basin 10. The bellows 11 is an expandable and contractible member, for example, a rubber bellows (rubber membrane).

[0039] In this embodiment, in the X-ray tube apparatus 1, coolant is taken in from the first cooling pipe 5b and flows into the inner pipe 7b from the upper end via the first passage 6p1. The coolant that flows into the inner pipe 7b collides with the protective film PR covering the bottom 14b of the anode block 14 in the direction in which the anode target 13 is installed, from the tip nozzle portion 24 of the inner pipe 7b. The coolant discharged from the tip nozzle portion 24 flows through a flow path formed by the inner surface of the anode block 14, or the inner surface of the outer pipe 7a, and the outer circumference of the inner pipe 7b, into the third passage 6p3 of the joint 6. The coolant that has flowed into the third passage 6p3 is removed from the second cooling pipe 5c via the second passage 6p2.

[0040] Furthermore, when a high-voltage cable is connected to the high-voltage receptacle 4 of the X-ray tube apparatus 1, a tube voltage is applied to the anode target 13. Then, electrons emitted from the cathode 15 strike the anode target 13, generating X-rays. At this time, the anode target 13 is cooled by the coolant flowing through the channel configured inside the anode block 14. Bubbles are generated in the coolant flowing through the channel inside the anode block 14 due to subcool boiling and cavitation.

[0041] Next, the hardness and thermal conductivity of the protective film PR according to this embodiment will be described. Figure 2 is a graph showing the change in hardness and thermal conductivity of the protective film PR with respect to the indium content in the protective film PR.

[0042] As shown in Figure 2, it can be seen that increasing the indium content in the protective film PR increases the hardness of the protective film PR, improving corrosion resistance and making it less susceptible to corrosion. The hardness of a protective film PR formed from hard gold containing 4 wt% or more indium is substantially more than twice that of a protective film formed from soft gold with 0 wt% indium content. However, it can be seen that increasing the indium content leads to a decrease in the thermal conductivity of the protective film PR. This is because the thermal conductivity of indium is lower than that of gold.

[0043] If the thermal conductivity of the protective film PR decreases, the cooling efficiency of the anode block 14 and anode target 13 decreases, and the surface (target surface) of the anode target 13 becomes more prone to deterioration (roughening). This can lead to a shorter product life of the X-ray tube apparatus 1 and a decrease in product reliability. For the reasons above, it is desirable that the hard gold contains 8 wt% or less of indium.

[0044] This is because if the amount of indium added to the hard gold exceeds 8 wt%, the thermal conductivity of the protective film PR decreases, accelerating the deterioration (roughening) of the surface of the anode target 13, and increasing the probability that the X-ray tube device 1 will not be able to meet its expected (designed) product life.

[0045] On the other hand, as the amount of indium added to the hard gold decreases, the corrosion resistance of the protective film PR gradually decreases, making the inside of the anode block 14 more susceptible to corrosion. For these reasons, it is desirable for the hard gold to contain 4 wt% or more of indium. If the amount of indium added to the hard gold is less than 4 wt%, corrosion inside the anode block 14 will be accelerated, increasing the probability that the X-ray tube device 1 will not be able to meet its expected (designed) product life. Based on the above, it is desirable that the indium concentration in hard gold be within the range of 4 to 8 wt%.

[0046] Generally, the following Hall-Petch formula is known for determining the hardness of metals. H = H0 + k·d -1 / 2 Here, H is the hardness, d is the diameter of the crystal grain (average grain size), and H0 and k are constants.

[0047] In this embodiment of hard gold, the addition of an additive (In) to the gold inhibits crystal growth, resulting in finer grain size and increased hardness. Therefore, in this embodiment, a protective film PR with more than twice the hardness of conventional films can be obtained, and the protective film PR can have excellent corrosion resistance.

[0048] According to the X-ray tube apparatus 1 configured as described above, the X-ray tube apparatus 1 comprises a cathode 15, an anode target 13, a first tube section (outer pipe 7a and anode block 14), a second tube section (inner pipe 7b), and a protective film PR covering the inner surface of the anode block 14. However, bubbles are generated due to boiling of the coolant or pressure differences within the coolant circuit, and the protective film PR is repeatedly subjected to shock waves when the bubbles disappear.

[0049] Therefore, if the protective film PR is made of soft gold, corrosion will occur in the protective film PR. Furthermore, corrosion and erosion by the coolant will gradually progress in the protective film PR, and in the worst case, it may penetrate to the anode block 14 and even further to the anode target 13, potentially causing a malfunction in which the coolant flows into the X-ray tube 2. In order to prevent corrosion and erosion by the coolant in the protective film PR, it is extremely difficult to suppress the generation of bubbles itself.

[0050] Therefore, in this embodiment, the protective film PR is formed from hard gold. Hard gold is made from a material in which indium is added to gold. The concentration of indium in hard gold is in the range of 4 to 8 wt%. The protective film PR can be obtained by forming a film of hard gold containing indium by a plating method. By forming the protective film PR with hard gold, which has a higher hardness than soft gold, the corrosion and erosion resistance of the protective film PR can be improved.

[0051] The amount of indium added to the hard gold is 4 to 8 wt%, and not less than 1 wt%. Compared to hard gold in which the amount of other metals added is less than 1 wt%, the proportion of indium in the hard gold of this embodiment is large, making the production of the hard gold of this embodiment easier.

[0052] Furthermore, in the hard gold of this embodiment, the amount of indium added is orders of magnitude greater than the amount of impurities. Compared to hard gold in which the amount of metals other than gold is less than 1 wt%, the properties of the hard gold of this embodiment (hardness, thermal conductivity, etc.) are less affected by the type and amount of impurities. Therefore, the quality of the hard gold of this embodiment is superior. From the above, it is possible to obtain an X-ray tube apparatus 1 that can extend the product lifespan.

[0053] (modified version) Next, a modified example of the above embodiment will be described. Figure 3 is a partially cross-sectional view showing an enlarged portion of the X-ray tube apparatus 1 according to the modified example. As shown in Figure 3, the reference plane S3 is defined as a virtual plane perpendicular to the axial direction da, through which the discharge port OL of the inner pipe 7b (second pipe section) passes. In the axial direction da, the reference inner surface S4 is defined as the inner surface (bottom surface S1 and inner circumferential surface S2) of the anode block 14 (first pipe section) that is on the anode target 13 side of the reference plane S3.

[0054] The protective film PR covers the reference inner surface S4 of the anode block 14. Boiling cooling is likely to occur on the anode target 13 side of the reference surface S3, but it is unlikely to occur on the first end 7be1 side of the inner pipe 7b (second pipe section) from the reference surface S3. Therefore, the protective film PR does not need to cover the inner circumferential surface S2 on the first end 7be1 side from the reference surface S3. From the viewpoint of the cooling efficiency of the anode target 13, it is desirable that the protective film PR covers at least the reference inner surface S4. In this modified example, the same effects as those of the above embodiment can be obtained.

[0055] While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. The novel embodiments described above can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0056] 1...X-ray tube apparatus, 2...X-ray tube, 3...Tube container, 6...Joint connection, 7...Water supply pipe, 7a...outer pipe, 7b...inner pipe, 7be1...first end, 7be2...second end 13... Anode target, 14... Anode block, 14b... Bottom, 14e... Other end, 15...Cathode, 17...First vacuum enclosure, 18...Second vacuum enclosure, 24...Tip nozzle section IL...Intake port, OL...Discharge port, S1...Bottom surface, S2...Inner peripheral surface, S3...Reference surface, S4...Reference inner surface, PR...Protective film, da...Axial direction.

Claims

1. A cathode that emits electrons, An anode target that generates X-rays when electrons emitted from the cathode strike it, A first pipe section having one end and the other end including a closed bottom to which the anode target is joined, The second pipe section has a first end located inside the first pipe section and having an intake port for taking in coolant, and a second end facing the bottom section and having an outlet port for discharging the coolant to the bottom section, and together with the first pipe section, forms a flow path for the coolant. The first pipe section comprises a protective film made of hard gold that covers the inner surface, The aforementioned hard gold is formed from a material in which indium is added to gold. The concentration of indium in the hard gold is in the range of 4 to 8 wt%. X-ray tube equipment.

2. The aforementioned hard gold contains 91.9 wt% or more gold. The X-ray tube apparatus according to claim 1.

3. The first pipe section extends in the axial direction, The inner surface of the first pipe section has a bottom surface, The bottom surface is the side of the bottom portion opposite to the side facing the anode target in the axial direction. The protective film covers the bottom surface of the inner surface. The X-ray tube apparatus according to claim 1.

4. The inner surface of the first pipe further has an inner circumferential surface that is continuously provided from the bottom surface, The protective film continuously covers from the bottom surface to the inner circumferential surface. The X-ray tube apparatus according to claim 3.

5. A virtual plane perpendicular to the axial direction and through which the discharge port of the second pipe section passes is used as the reference plane. If the inner surface of the first tube portion that is on the anode target side of the reference surface is defined as the reference inner surface, The protective film covers the reference inner surface among the inner surfaces. The X-ray tube apparatus according to claim 4.

6. The aforementioned coolant is a water-based coolant. The X-ray tube apparatus according to claim 1.

Images