X-ray tube and method of manufacturing an x-ray tube

Abstract

An X-ray tube according to an embodiment includes a periphery that keeps the inside in vacuum, an anode target that generates X-rays by collision of hot electrons, and a cathode electron gun that emits the hot electrons to the anode target, and includes a periphery assembly that has a metal cylindrical support body fixing portion and constitutes the periphery, and a cathode assembly that has a metal support body that holds the cathode electron gun at a front end portion, and in the support body fixing portion, the support body of the cathode assembly is fixed at an inner peripheral side by welding.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to an X-ray tube and a manufacturing method of an X-ray tube. BACKGROUND

[0002] In an X-ray tube for analysis or other use, a peripheral vessel that maintains an internal vacuum is formed of an insulator such as metal, ceramic, glass, or the like. The components of the X-ray tube are joined by brazing, welding, or glass sealing, or the like, and have a configuration that maintains a vacuum. In particular, the joining between a ceramic component and a metal component and the joining between metal components are joined by brazing or welding.

[0003] Further, although each component is provided with a dimensional tolerance, particularly on the basis of looseness in a fitting portion or a connecting portion, each dimensional tolerance and looseness accumulates depending on the number of assembled components, and the looseness with respect to the anode target under the completed shape, the distance between the cathode electron gun, and the shape of the focal point become large, and a large deviation in the shape of the focal point can occur.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent No. 3152717

[0007] Patent Document 2: Japanese Patent No. 5370967 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The shape of the focal point not only affects the analysis performance, but also affects the life of the X-ray tube. For example, if the focal point becomes smaller than required, the X-ray intensity, the resolution as the analysis performance become high, but the temperature of the focal plane rises, and the melting of the focal plane accelerates, and the life of the X-ray tube becomes short. Conversely, if the focal point becomes large, the life of the X-ray tube becomes long, but the X-ray intensity, the resolution as the analysis performance become low.

[0010] Therefore, it is desirable to obtain an X-ray tube and a manufacturing method of an X-ray tube that can reduce the deviation in the shape of the focal point.

[0011] The present embodiment provides an X-ray tube and a manufacturing method of an X-ray tube that can absorb the effects of the dimensional tolerance of the components and the looseness at the time of assembly, and can reduce the deviation in the shape of the focal point on the anode target.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] In one embodiment, the X-ray tube includes: an outer casing that maintains the interior as a vacuum; an anode target disposed within the outer casing and generating X-rays by the collision of thermionic electrons; and a cathode electron gun disposed within the outer casing and emitting thermionic electrons toward the anode target. The X-ray tube further includes: a cathode assembly having a metallic support at its front end for holding the cathode electron gun; and an outer casing assembly having a support fixing portion for fixing the support of the cathode assembly and constituting the outer casing. The support fixing portion is cylindrical in shape and the support of the cathode assembly is fixed to its inner circumference by welding.

[0014] In another embodiment, in a method for manufacturing an X-ray tube, the X-ray tube includes: an outer casing that maintains its interior as a vacuum; an anode target disposed within the outer casing and generating X-rays through the collision of thermionic electrons; and a cathode electron gun disposed within the outer casing and emitting thermionic electrons toward the anode target. The X-ray tube further includes: a cathode assembly having a metal support at its front end for holding the cathode electron gun; an outer casing assembly formed by connecting a metal cylindrical support fixing portion that fixes the support of the cathode assembly to a ceramic cylindrical outer casing body between one end of the outer casing body and the outer peripheral surface of the support fixing portion using a metal connecting member; and an anode assembly. The X-ray tube has a metal bottom cylinder portion that forms part of the peripheral device, the anode target is held on the inner bottom surface of the bottom cylinder portion, and an X-ray transmission window is provided on the side surface of the bottom cylinder portion. The manufacturing method of the X-ray tube includes: an insertion step in which the cathode assembly is inserted from the front end into the interior of the peripheral device assembly inside the support body fixing portion of the peripheral device assembly; a cathode assembly positioning step after the insertion step in which the front end of the cathode assembly is positioned to a predetermined position; and a cathode assembly welding step after the cathode assembly positioning step in which the rear end of the support body of the cathode assembly is fixed to the support body fixing portion of the peripheral device assembly by welding. Attached Figure Description

[0015] Figure 1 This is a longitudinal sectional view showing a simplified structure of an X-ray tube according to one embodiment.

[0016] Figure 2 It is shown Figure 1 The longitudinal section shows a simplified structure of the peripheral component.

[0017] Figure 3 It is shown Figure 1 The longitudinal section of the simplified structure of the cathode assembly is shown.

[0018] Figure 4 is a longitudinal sectional view showing Figure 1 a brief structure of the anode assembly.

[0019] Figure 5 is a longitudinal sectional view showing DETAILED DESCRIPTION

[0020] Hereinafter, an X-ray tube and a manufacturing method of the X-ray tube according to one embodiment will be described in detail with reference to the drawings. In order to make the description more clear, the width, thickness, shape, and the like of each portion are sometimes schematically shown in the drawings compared to the actual ones, but this is only one example and cannot be used to limit the interpretation of the present application. In the present specification and each drawing, the same reference numerals are assigned to constituent elements having the same or similar functions as those in the previously described drawings, and sometimes the repeated detailed description will be appropriately omitted.

[0021] As shown in Figure 1 , the X-ray tube 1 includes an envelope 3 that keeps the inside in vacuum, and an anode target 5 and a cathode electron gun 7 provided inside the envelope 3, so that the hot electrons 2 emitted from the cathode electron gun 7 hit the anode target 5 to generate X-rays 4.

[0022] The X-ray tube 1 is composed of three assemblies, an envelope assembly 11, a cathode assembly 13, and an anode assembly 15.

[0023] As shown in Figure 2 and Figure 1 , the envelope assembly 11 includes an envelope main body 17, a support body fixing portion 19 for fixing a support body (to be described later) of the cathode assembly 13, a first connecting member 21 provided at one end of the envelope main body 17 and connecting the envelope main body 17 and the support body fixing portion 19, and a second connecting member 23 provided at the other end of the envelope main body 17.

[0024] The envelope main body 17 is made of ceramic and formed in a cylindrical shape. One end 17a and the other end 17b of the envelope main body 17 are formed with metallized portions 18, respectively, to become metal surfaces.

[0025] The support body fixing portion 19 is made of metal such as stainless steel and formed in a cylindrical shape. As shown in Figure 1 , the cathode assembly 13 is inserted inside the support body fixing portion 19, and the inner peripheral surface 19a of the support body fixing portion 19 becomes a sliding surface of the cathode assembly 13.

[0026] The first connecting member 21 is made of metal such as Kovar (KOV) and disposed between the one end 17a of the envelope main body 17 and the outer peripheral surface 19b of the support body fixing portion 19 as a part of the envelope 3 to block between them (refer to Figure 1The connecting member 21 forms a ring shape.

[0027] One end (inner peripheral end) 21a of the first connecting member 21 on the support body fixing part 19 side is brazed to the outer peripheral surface 19b of the support body fixing part 19. One end (outer peripheral end) 21b of the first connecting member 21 on the peripheral body 1 side is brazed to one end 17a of the peripheral body 17.

[0028] Furthermore, one end 23a of the second connecting member 23 is brazed to the other end 17b of the peripheral body 17. The second connecting member 23 is made of a metal such as Kovar alloy (KOV) and is formed in a ring shape along the shape of the other end 17b of the peripheral body 17; in this embodiment, it is a circular ring.

[0029] like Figure 3 and Figure 1 As shown, the cathode assembly 13 includes a cathode electron gun 7 and a support 27 for supporting the cathode electron gun 7.

[0030] The support body 27 is made of stainless steel or other metal and is cylindrical, with the cathode electron gun 7 held at the front end 27a. Figure 1 As shown, the support body 27 is inserted into the inner periphery of the support body fixing part 19 of the peripheral assembly 11, and the rear end 27b of the support body 27 is fixed to the outer end 19c of the support body fixing part 19 by welding.

[0031] The front end 27a of the support body 27 has a concave electron gun holding part 27c for mounting the cathode electron gun 7, which is either flush with the front end of the cathode electron gun 7 or protruding from either of them.

[0032] The support body 27 is cylindrical, and a ceramic sealing member 29 is disposed on the inner side of the cylinder at a position corresponding to the support body fixing part 19 of the peripheral device assembly 11. The wiring 7a and 7b of the cathode electron gun 7 are led out from the inner side of the support body 27 to the outer side of the peripheral device 3 through the sealing member 29.

[0033] like Figure 4 and Figure 1 As shown, the anode assembly 15 has a bottomed cylindrical portion 31 made of a metal such as pure copper, which forms part of the peripheral device 3. The bottomed cylindrical portion 31 consists of a cylindrical side portion 31a and a bottom portion 31b that blocks one end of the cylinder, and the anode target 5 is held on the inner bottom surface of the bottom portion 31b. An X-ray transmission window 33 is provided on the side portion 31a. The X-ray transmission window 33 is made of a light element such as beryllium (Be).

[0034] like Figure 1 As shown, the other end 23b of the second connecting member 23 is fixed to the end face 31c of the bottom cylinder portion 31 by welding.

[0035] Next, a manufacturing method of the X-ray tube 1 according to the present embodiment will be described.

[0036] First, the manufacturing of each component 11, 13, 15 will be described.

[0037] As shown in FIG. 1, in the outer peripheral processor 11, a metalized portion 18 is formed at one end 17a and the other end 17b of the cylindrical outer peripheral main body 17, and the one end (outer peripheral end) 21b of the outer peripheral main body 17 side of the first connecting member 21 is positioned at the one end 17a and the one end 23a of the second connecting member 23 is positioned at the other end 17b at the prescribed positions using a jig or the like. Figure 2

[0038] Next, the cylindrical support fixing portion 19 is slidably inserted into the one end (inner peripheral end) 21a of the first connecting member 21a, and is positioned at the prescribed position using a jig or the like. In the positioning, the support fixing portion 19 is positioned in such a manner that the distance H2 between the other end 17b of the outer peripheral main body 17 and the outer side end 19c of the support fixing portion 19 becomes a prescribed distance.

[0039] After the positioning of the support fixing portion 19 is performed, the one end 17a of the cylindrical outer peripheral main body 17 and the other end 21b of the first connecting member 21, the other end 17b of the outer peripheral main body 17 and the one end 23a of the second connecting member 23, and the one end 21a of the first connecting member 21 and the outer peripheral surface 19b of the support fixing portion 19 are soldered to be fixed.

[0040] As shown in FIG. 1, in the outer peripheral processor 11, a metalized portion 18 is formed at one end 17a and the other end 17b of the cylindrical outer peripheral main body 17, and the one end (outer peripheral end) 21b of the outer peripheral main body 17 side of the first connecting member 21 is positioned at the one end 17a and the one end 23a of the second connecting member 23 is positioned at the other end 17b at the prescribed positions using a jig or the like. Figure 3

[0041] As shown in FIG. 1, in the outer peripheral processor 11, a metalized portion 18 is formed at one end 17a and the other end 17b of the cylindrical outer peripheral main body 17, and the one end (outer peripheral end) 21b of the outer peripheral main body 17 side of the first connecting member 21 is positioned at the one end 17a and the one end 23a of the second connecting member 23 is positioned at the other end 17b at the prescribed positions using a jig or the like. Figure 4

[0042] Next, the assembly of each component 11, 13, and 15 will be described.

[0043] As shown in FIG. 1, in the outer peripheral processor 11, a metalized portion 18 is formed at one end 17a and the other end 17b of the cylindrical outer peripheral main body 17, and the one end (outer peripheral end) 21b of the outer peripheral main body 17 side of the first connecting member 21 is positioned at the one end 17a and the one end 23a of the second connecting member 23 is positioned at the other end 17b at the prescribed positions using a jig or the like. Figure 2 Figure 1 As shown in FIG. 1, in the outer peripheral processor 11, a metalized portion 18 is formed at one end 17a and the other end 17b of the cylindrical outer peripheral main body 17, and the one end (outer peripheral end) 21b of the outer peripheral main body 17 side of the first connecting member 21 is positioned at the one end 17a and the one end 23a of the second connecting member 23 is positioned at the other end 17b at the prescribed positions using a jig or the like. ​​​​

[0044] Specifically, as shown in Figure 5 the positioning jig 35 is attached to the second connecting member 23 of the periphery assembly 11, as shown in Figure 5 the support body 27 of the cathode assembly 13 is inserted into the inside of the cylindrical support body fixing portion 19. The support body 27 inserts the cathode electron gun 7 toward the inside of the periphery body 17.

[0045] Next, as shown in Figure 5 the lower end of the support body 27 holding the cathode electron gun 7 is brought into abutment with the positioning jig 35 to position the cathode assembly 13.

[0046] After the support body 27 of the cathode assembly 13 is positioned to the support body fixing portion 19, as shown in Figure 1 the rear end 27b of the support body 27 is fixed to the outside end 19c of the support body fixing portion 19 by welding at this position.

[0047] Next, as shown in Figure 1 in the periphery body 17 of the periphery assembly 11, the end face 31c of the bottomed cylindrical portion 31 of the anode assembly 15 is fixed to the other end 23b of the second connecting member 23 by welding.

[0048] As described above, the periphery assembly 11, the cathode assembly 13, and the anode assembly 15 are assembled to manufacture the X-ray tube 1.

[0049] The function of the X-ray tube 1 is described.

[0050] As shown in Figure 1 the thermal electrons 2 generated from the cathode electron gun 7 are accelerated by a high voltage and hit the anode target 5 to generate X-rays 4. The generated X-rays 4 are taken out from the X-ray transmission window 33 and used for analysis, etc.

[0051] The effect of the X-ray tube 1 according to the present embodiment is described.

[0052] As shown in Figure 1 in the periphery 3, the distance H3 between the cathode electron gun 7 and the anode target 5 can be adjusted by sliding the support body fixing portion 19 of the periphery assembly 11, as shown in Figure 5 the support body 27 holding the cathode electron gun 7 is positioned, so that the positioning of the cathode electron gun 7 with respect to the anode target 5 can be performed accurately and easily.

[0053] In particular, by directly performing the positioning of the cathode electron gun 7 with respect to the anode target 5, even if there is a tolerance in the distance H1 of the ceramic periphery body 17, the influence thereof can be reduced.

[0054] In maintaining the positioning of the support 27 of the cathode electron gun 7, positioning is made easier by bringing the front end 27a of the support 27 into contact with the positioning fixture 35 corresponding to the position of the anode target 5.

[0055] According to this embodiment, the distance between the cathode electron gun 7 and the anode target 5, which are in the focal shape of the left and right X-ray tubes, can be manufactured within an error range of less than 0.1 mm.

[0056] like Figure 2 As shown, in the peripheral device assembly 11, when the support fixing part 19, the peripheral device body 17, and the first connecting member 21 are fixed by brazing, the distance H2 between the other end 17b of the peripheral device body 17 and the outer end 19c of the support fixing part 19 is positioned, thus improving the dimensional accuracy of the peripheral device assembly 11 and enabling more accurate positioning of the distance H3 between the cathode electron gun 7 and the anode target 5 when assembling the cathode assembly 13 (refer to...). Figure 1 (To locate)

[0057] In the X-ray tube 1 described in this embodiment, the components related to the distance H3 between the cathode electron gun 7 and the anode target 5, which are shaped with the left and right focal points, are made of metal except for the ceramic peripheral body 17. This makes it easy to perform precision machining and assembly.

[0058] According to this embodiment, the X-ray tube 1 is composed of three components: an outer device assembly 11, a cathode assembly 13, and an anode assembly 15. Each component 11, 13, and 15 is assembled while being positioned, thus enabling efficient manufacturing.

[0059] The above-described embodiment is merely an example and not a limitation on the scope of protection of this invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The above-described embodiments and their variations are all included within the scope and spirit of this invention, and are included within the scope of the invention described in the claims of this patent application and its equivalents.

Claims

1. An X-ray tube, comprising: An external device that maintains its internal vacuum; An anode target disposed within the peripheral device and generating X-rays through the collision of hot electrons; The X-ray tube is characterized by comprising: a cathode electron gun disposed within the peripheral device and emitting thermionic electrons to the anode target; and a cathode electron gun that emits thermionic electrons to the anode target. A cathode assembly having a metal support body that holds the cathode electron gun at a front end, the metal support body having a cylindrical shape from the front end to the rear end, and the cathode electron gun being disposed in a cathode electron gun holding portion on the inner circumferential side of the front end of the metal support body. An external device assembly having a support fixing portion for fixing the support body of the cathode assembly, and constituting the external device; as well as The anode assembly has a bottomed metal cylindrical portion that forms part of the peripheral device, the anode target is held on the inner bottom surface of the bottomed cylindrical portion, and an X-ray transmission window is provided on the side surface of the bottomed cylindrical portion. The support fixing part of the peripheral device assembly is a metal cylinder. The support body of the cathode assembly is positioned by sliding along the inner circumference of the support fixing part, and then fixed to the inner circumference by welding. The peripheral device assembly has a cylindrical peripheral device body made of ceramic, one end of which is connected to the outer peripheral surface of the support fixing part by a metal connecting member. The open end of the bottom cylinder of the anode assembly is fixed to the other end of the outer casing body.

2. A method for manufacturing an X-ray tube, the X-ray tube comprising: An external device that maintains its internal vacuum; An anode target disposed within the peripheral device and generating X-rays through the collision of hot electrons; The method of manufacturing the X-ray tube is characterized in that the X-ray tube comprises: and a cathode electron gun disposed within the peripheral device and emitting thermionic electrons to the anode target. A cathode assembly having a metal support body that holds the cathode electron gun at a front end, the metal support body having a cylindrical shape from the front end to the rear end, and the cathode electron gun being disposed in a cathode electron gun holding portion on the inner circumferential side of the front end of the metal support body. An external device assembly, which utilizes a metal connecting member to connect a metal cylindrical support fixing part of the support body for fixing the cathode assembly to a ceramic cylindrical external device body between one end of the external device body and the outer peripheral surface of the support fixing part; and The anode assembly has a bottomed metal cylindrical portion that forms part of the peripheral device, the anode target is held on the inner bottom surface of the bottomed cylindrical portion, and an X-ray transmission window is provided on the side surface of the bottomed cylindrical portion. The manufacturing method of the X-ray tube includes: an insertion process of inserting the cathode assembly from the front end inside the peripheral component at the inner side of the support fixing portion of the peripheral component; a cathode assembly positioning process of positioning the position of the front end portion of the cathode assembly to a prescribed position by sliding the support of the cathode assembly along the inner peripheral side of the support fixing portion after the insertion process; and a cathode assembly welding process of fixing the rear end of the support of the cathode assembly to the support fixing portion of the peripheral component by welding after the cathode assembly positioning process.

3. The manufacturing method of the X-ray tube according to claim 2, further comprising a support fixing portion positioning process of positioning the position of the support fixing portion with respect to the connecting member in the peripheral component.

4. The manufacturing method of the X-ray tube according to claim 2, wherein in the cathode assembly positioning process, a positioning jig is provided at the other end side of the peripheral component main body, and the front end of the cathode assembly is positioned by abutting against the positioning jig.

5. The manufacturing method of the X-ray tube according to claim 2, further comprising an anode assembly connecting process of connecting the open end portion of the bottomed cylindrical portion of the anode assembly to the other end of the peripheral component after the cathode assembly welding process. ​ ​ ​

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