Acceleration cavity and method for manufacturing acceleration cavity

Abstract

To provide an easily manufactured acceleration cavity and a method for manufacturing the acceleration cavity.SOLUTION: An acceleration cavity includes a casing that has a conductive cylindrical shape and is formed by joining a plurality of divided members divided by a planar dividing plane along a central axis, a plurality of cell portions arranged in a line in the axial direction of the central axis of the casing inside the casing and communicated with each other by a communication portion through which charged particles can pass, and a protrusion portion that is placed in a position surrounding the communication portion for each cell portion inside the casing, and protrudes toward the inside of each cell portion in the axial direction, and is formed in a shape that expands in the radial direction with the central axis as a reference from the distal end side to the proximal end side in the axial direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an accelerating cavity and a method for manufacturing an accelerating cavity. [Background technology]

[0002] When a high frequency wave is input into an acceleration cavity, an acceleration electric field is generated inside the cavity, and the acceleration of charged particles such as electrons is achieved. For example, a configuration is known for such an acceleration cavity, in which a plurality of cell parts are arranged in the axial direction of a central axis, the cell parts are connected to each other by communication parts, and a protrusion called a nose cone is provided at a position surrounding each communication part of the cell parts (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-107499 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, a method has been proposed for manufacturing the above-mentioned accelerating cavity, in which divided members are formed in advance at dividing surfaces on a plane along the central axis, and the divided members are joined together at the dividing surfaces. When using this method, an accelerating cavity having a protrusion (nose cone) as described in Patent Document 1 is required to be easily manufactured.

[0005] The present disclosure has been made in consideration of the above, and has an object to provide an acceleration cavity that can be easily manufactured and a method for manufacturing the acceleration cavity. [Means for solving the problem]

[0006] The acceleration cavity of the present disclosure comprises a cylindrical, conductive housing formed by joining multiple divided members at planar dividing surfaces along a central axis, a plurality of cell sections arranged inside the housing in a line along the axial direction of the central axis of the housing and connected to each other by communicating sections that allow charged particles to pass through, and protrusions arranged inside the housing at positions surrounding the communicating sections for each cell section, protruding toward the inside of each cell section in the axial direction, and formed in a shape that expands radially with respect to the central axis from the tip end side to the base end side in the axial direction.

[0007] The method for manufacturing an acceleration cavity according to the present disclosure is a method for manufacturing an acceleration cavity comprising: a conductive cylindrical casing formed by joining multiple divided members at a planar dividing surface along a central axis; a plurality of cell sections arranged inside the casing in a line along the axial direction of the central axis of the casing and connected to each other by communicating parts that allow charged particles to pass through; and protrusions arranged inside the casing at positions surrounding the communicating parts for each of the cell sections and protruding toward the inside of each of the cell sections in the axial direction, the method including the steps of: cutting a workpiece surface of a base material having a workpiece surface corresponding to the dividing surface to form recesses corresponding to the multiple cell sections and the communicating parts; and inserting a cutting tool into the recess from the workpiece surface side to form a portion corresponding to the protrusion so as to have a shape that expands radially from the tip side to the base side in the axial direction of the central axis. Effect of the Invention

[0008] According to the present disclosure, it is possible to provide an acceleration cavity that can be easily manufactured and a method for manufacturing the acceleration cavity. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing an example of an accelerating cavity according to this embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration along the cross section AA in FIG. [Diagram 3]FIG. 3 is a diagram showing a configuration along the cross section BB in FIG. [Figure 4] FIG. 4 is a perspective view showing an example of a protruding portion. [Diagram 5] FIG. 5 is a perspective view showing an example of a unit protrusion in one divided member. [Figure 6] FIG. 6 is a diagram showing a configuration along the CC cross section in FIG. [Figure 7] FIG. 7 is a flowchart showing an example of a method for manufacturing an accelerating cavity according to this embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the recess forming step. [Figure 9] FIG. 9 is a diagram illustrating an example of the protrusion forming step. [Figure 10] FIG. 10 is a diagram showing an accelerating cavity according to another example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of an acceleration cavity and a method for manufacturing an acceleration cavity according to the present disclosure will be described with reference to the drawings. Note that the present invention is not limited to these embodiments. In addition, components in the following embodiments include those that are replaceable and easy for a person skilled in the art, or those that are substantially the same.

[0011] Fig. 1 is a plan view showing an example of an acceleration cavity 100 according to this embodiment. Fig. 2 is a diagram showing a configuration along the AA cross section in Fig. 1. Fig. 3 is a diagram showing a configuration along the BB cross section in Fig. 1.

[0012] The acceleration cavity 100 shown in Figs. 1 to 3 generates an acceleration electric field therein by inputting high frequency waves, and accelerates charged particles M, such as electrons, emitted from a radiation source BS. The acceleration cavity 100 and the radiation source BS are used to configure an accelerator AC. The accelerator AC is used in various fields, such as academic fields such as high energy physics experiments and synchrotron radiation facilities, medical fields such as radiation therapy or inspection, and industrial fields such as non-destructive inspection. In the following description, when describing the axial direction of the central axis AX among the directions in the acceleration cavity 100, the radiation source BS side (the side where the charged particles M are incident) is referred to as the incident side, and the opposite side to the incident side (the side where the charged particles are emitted) is referred to as the exit side.

[0013] As shown in FIGS. 1 to 3, an acceleration cavity 100 according to this embodiment includes a housing 10, a cell unit 20, and a protruding portion 30. The acceleration cavity 100 includes a housing 10, a cell unit 20, and a protruding portion 30. The cell unit 20 includes a housing 10a.

[0014] The housing 10 has a cylindrical shape having electrical conductivity. The housing 10 is formed by joining a plurality of divided members 11. The divided members 11 have planar divided surfaces 12 along the central axis AX. The divided members 11 are joined with the divided surfaces 12 facing each other. The divided members 11 are provided with a gap between the opposing divided surfaces 12. In this embodiment, a configuration in which the housing 10 is divided into two in the vertical direction will be described as an example. The number of divisions of the housing 10 is not limited to two, and may be three or more. The divided members 11 have a shape in which the parts facing each other are generally rounded. This suppresses local application of voltage.

[0015] The cell units 20 are formed inside the housing 10. The cell units 20 are arranged side by side in the axial direction of the central axis AX of the housing 10. The cell units 20 are connected to each other by communication units 21 that allow charged particles to pass through. The communication units 21 are formed along the central axis AX. The cell unit 20 is formed by combining unit cell units 23 provided in each of the upper and lower divided members 11. The communication units 21 are also formed by combining unit communication units 24 provided in each of the upper and lower divided members 11.

[0016] The protrusions 30 are provided for each cell unit 20 inside the housing 10. The protrusions 30 are arranged at positions surrounding the communication unit 21. The protrusions 30 are arranged on both the incident side and the exit side in the axial direction of the central axis AX. The protrusions 30 provided on the incident side of each cell unit 20 protrude toward the exit side in the axial direction of the central axis AX. The protrusions 30 provided on the exit side of each cell unit 20 protrude toward the incident side in the axial direction of the central axis AX. That is, the protrusions 30 each protrude toward the inside of the cell unit 20. The protrusions 30 are formed by combining unit protrusions 33 provided on each of the upper and lower divided members 11.

[0017] Fig. 4 is a perspective view showing an example of the protruding portion 30. Fig. 4 shows the configuration of the protruding portion 30 as viewed from the tip portion 32 side.

[0018] The protrusion 30 is formed in a shape that expands in a radial direction based on the central axis AX from the tip end 32 side in the axial direction of the central axis AX to the base end 31 side. The radial direction is the radial direction when viewed from the axial direction of the central axis AX.

[0019] The protrusion 30 is composed of unit protrusions 33 provided for each divided member 11. Fig. 5 is a perspective view showing an example of a unit protrusion 33 in one divided member 11. The unit protrusions 33 are formed so as to expand radially as they move away from the dividing surface 12 in the direction around the central axis AX. Note that although imaginary lines indicating boundaries between a base end curved portion 34a, a tip end curved portion 34b, and a connecting portion 34c, which will be described later, are shown in Figs. 4 and 5, the boundaries are not actually visible.

[0020] Fig. 6 is a diagram showing a configuration along the CC cross section in Fig. 3. Fig. 6 shows a cross section of a unit protrusion 33 at a position farthest from the dividing surface 12 in the direction around the central axis AX (a position of φ=90° in Fig. 5). In Fig. 6, an outer peripheral surface 34 of the unit protrusion 33 has a base end curved portion 34a, a tip end curved portion 34b, and a connecting portion 34c.

[0021] The base-end curved portion 34a is a portion that constitutes the base end portion 31. The base-end curved portion 34a is, for example, in the shape of a circular arc having a predetermined radius R in the cross-sectional shape of Fig. 6. The radius R can be set in advance.

[0022] The distal curved portion 34b is a portion that constitutes the distal end portion 32. The distal curved portion 34b is formed in an arbitrary curved shape, such as an arc shape. The shape of the distal curved portion 34b may be set in advance or may be set according to the connection position 34d described later.

[0023] The connecting portion 34c connects the base end curved portion 34a and the tip end curved portion 34b. The connecting portion 34c may include, for example, a straight portion. The connecting portion 34c may be entirely straight, or may have a shape that does not include a straight portion. The shape of the connecting portion 34c may be set in advance, or may be set according to the connecting position 34d described later.

[0024] The base end curved portion 34a and the connecting portion 34c are smoothly connected to each other, and the tip end curved portion 34b and the connecting portion 34c are smoothly connected to each other.

[0025] At a position that is at a predetermined angle φ from the dividing surface 12 in the direction around the central axis AX, the connection position 34d between the distal curved portion 34b and the connection portion 34c can be set as follows: In other words, if the angle between a first imaginary straight line L1 that is perpendicular to the tangent at the connection position 34d and a second imaginary straight line L2 that is perpendicular to the central axis AX is α(φ), then α(φ) ∝(sinφ) n (where n is a positive real number). In this embodiment, the value of n may be, for example, a natural number. When the value of n is a natural number, it may be, for example, n=6. When the value of n is a natural number, it is not limited to 6 and may be 5 or less or 7 or more.

[0026] The angle θ between the second virtual straight line L2 and the connection portion 34c can be set arbitrarily so as to have a minimum value at φ=90°. In the example shown in FIG. 6, θ=60°, but is not limited to this value.

[0027] Next, a method for manufacturing the acceleration cavity 100 configured as described above will be described. Fig. 7 is a flowchart showing an example of a method for manufacturing the acceleration cavity 100 according to this embodiment. As shown in Fig. 7, the method for manufacturing the acceleration cavity 100 according to this embodiment includes a recess forming step S10, a protrusion forming step S20, and a bonding step S30.

[0028] Fig. 8 is a diagram showing an example of the recess forming step S10. Fig. 8 shows a representative example of one cell portion 20. As shown in Fig. 8, in the recess forming step S10, a base material 50 has a processed surface 52 corresponding to the dividing surface 12, and the processed surface 52 is cut to form recesses 51 corresponding to the multiple cell portions 20 and the communication portions 21.

[0029] Fig. 9 is a diagram showing an example of the protrusion forming step S20. Fig. 9 shows one cell portion 20 as a representative, as in Fig. 8. As shown in Fig. 9, in the protrusion forming step S20, a cutting tool T is inserted into a recess 51 from the work surface 52 side to form a unit protrusion 33 corresponding to the protrusion 30 so as to have a shape expanding in the radial direction based on the central axis AX from the tip end 32 side to the base end 31 side in the axial direction of the central axis AX. By forming the unit protrusion 33 in the base material 50, a divided member 11 is formed.

[0030] Since the shape of the unit protrusion 33 expands radially from the tip end 32 toward the base end 31, based on the central axis AX, when a cutting tool T is inserted to cut a position of the unit protrusion 33 that is away from the workpiece surface 52 in the direction around the central axis AX, interference between the cutting tool T and the unit protrusion 33 can be suppressed.

[0031] In the joining step S30, the formed divided members 11 are joined together. The divided members 11 are joined together such that the divided surfaces 12 face each other with a predetermined gap therebetween. By joining the divided members 11 together, the acceleration cavity 100 is formed.

[0032] The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention.

[0033] FIG. 10 is a diagram showing an acceleration cavity 200 according to another example. As shown in FIG. 10, the acceleration cavity 200 may have a configuration in which the housing 110 has three or more divided members 111. In the example shown in FIG. 10, four divided members 111 are provided. The four divided members 111 are configured to be divided into equal dimensions in the direction around the central axis AX by a plane passing through the central axis AX. The cell portion 120 is configured by combining unit cell portions 123 provided in each of the four divided members 111. The communication portion 121 is configured by combining unit communication portions 124 provided in each of the four divided members 111.

[0034] In the acceleration cavity 200, two dividing surfaces 112 are provided for each divided member 111 so as to be perpendicular to each other. In this case, the protrusions 130 are formed so as to expand radially as they move away from the dividing surfaces 112 in the direction around the central axis AX. That is, in each divided member 111, the unit protrusions 133 are formed so that the outer peripheral surface 134 expands radially in a direction in which the angle between the two dividing surfaces 112 is 45° in the direction around the central axis AX.

[0035] Although the case where the acceleration cavity 200 is divided into four has been described in FIG. 10 as an example, the same description can be applied to the case where the acceleration cavity is divided into three or five or more.

[0036] Here, if the number of divisions of the acceleration cavity is M, then the connection position 34d between the tip side curved portion 34b of the protrusion 30 and the connection portion 34c is given by: α(φ) ∝(sinφ) n satisfies the above condition, in the range where the value of φ is equal to or greater than 0 and less than π / 2M, and in the range where the value of φ is equal to or greater than π / M and less than 3π / 2M, the value of α(φ) increases as the value of φ increases, that is, α(φ) increases monotonically.

[0037] On the other hand, in the range where the value of φ is greater than or equal to π / 2M and less than π / M, and in the range where the value of φ is greater than or equal to 3π / 2M and less than 2π / M, the value of α(φ) decreases as the value of φ increases, that is, α(φ) monotonically decreases.

[0038] As described above, the acceleration cavity according to the first aspect of the present disclosure is an acceleration cavity 100 having a cylindrical conductive housing 10 formed by joining multiple divided parts 11 at planar dividing surfaces 12 along the central axis AX, a plurality of cell sections 20 arranged inside the housing 10 in a line-up in the axial direction of the central axis AX of the housing 10 and connected to each other by communicating parts 21 that allow charged particles to pass through, and protrusions 30 arranged in positions surrounding the communicating parts 21 for each cell section 20 inside the housing 10, protruding in the axial direction toward the inside of each cell section 20 and formed so as to radially expand as they move away from the dividing surface 12 in the direction around the central axis AX from the tip end 32 side toward the base end 31 side in the axial direction.

[0039] According to this configuration, the shape of the protrusion 30 expands in the radial direction based on the central axis AX from the tip end 32 side toward the base end 31 side. Therefore, when manufacturing the divided member 11, when a cutting tool T is inserted to cut a position of the unit protrusion 33 away from the workpiece surface 52 in the direction around the central axis AX, interference between the cutting tool T and the unit protrusion 33 can be suppressed. Therefore, an acceleration cavity 100 that can be easily manufactured can be provided.

[0040] The acceleration cavity according to the second aspect of the present disclosure is the acceleration cavity according to the first aspect, wherein the protrusion 30 has a base-side curved portion 34a constituting the base end 31, a tip-side curved portion 34b constituting the tip end 32, and a connecting portion 34c connecting the base-side curved portion 34a and the tip-side curved portion 34b, and there is a smooth connection between the base-side curved portion 34a and the connecting portion 34c, and between the tip-side curved portion 34b and the connecting portion 34c.

[0041] According to this configuration, the base-side curved portion 34a and the connecting portion 34c, and the tip-side curved portion 34b and the connecting portion 34c are smoothly connected to each other, so that the entire protrusion 30 is formed with a smooth surface. Therefore, when the acceleration cavity 100 is used, it is possible to prevent the occurrence of a portion of the protrusion 30 to which an excessive voltage is applied.

[0042] The acceleration cavity according to the third embodiment of the present disclosure is similar to the acceleration cavity according to the second embodiment in that the base-end curved portion 34a is arc-shaped and the connecting portion 34c includes a straight portion in a cross-sectional view taken along a plane passing through the central axis AX.

[0043] According to this configuration, it is possible to easily design a configuration in which the base end portion 31 side of the protrusion 30 is expanded in the radial direction.

[0044] In the acceleration cavity according to the fourth aspect of the present disclosure, in the acceleration cavity according to the second or third aspect, at a position that is a predetermined angle φ from the dividing surface 12 in a direction around the central axis AX, a connection position 34d between the tip side curved portion 34b and the connection portion 34c has an angle α(φ) between a first imaginary line orthogonal to a tangent at the connection position 34d and a second imaginary line perpendicular to the central axis AX, where α(φ) is an angle and n is a positive real number, α(φ) ∝(sinφ) n is set to satisfy

[0045] According to this configuration, the tip portion 32 side of the protrusion 30 can be designed easily and appropriately.

[0046] A manufacturing method of an acceleration cavity according to a fifth aspect of the present disclosure is a manufacturing method of an acceleration cavity including a cylindrical conductive housing 10 formed by joining a plurality of divided members 11 at planar dividing surfaces 12 along a central axis AX, a plurality of cell sections 20 arranged inside the housing 10 in a lined-up state in the axial direction of the central axis AX of the housing 10 and connected to each other by communicating parts 21 through which charged particles can pass, and protrusions 30 arranged inside the housing 10 at positions surrounding the communicating parts 21 for each cell section 20 and protruding toward the inside of each cell section 20 in the axial direction, the manufacturing method including the steps of: cutting a workpiece surface 52 of a base material having the workpiece surface 52 corresponding to the dividing surfaces 12 to form recesses 51 corresponding to the plurality of cell sections 20 and the communicating parts 21; and inserting a cutting tool T into the recesses 51 from the workpiece surface 52 side to form unit protrusions 33 corresponding to the protrusions 30 so as to have a shape that expands in a radial direction based on the central axis AX from the tip end 32 side toward the base end 31 side in the axial direction of the central axis AX.

[0047] According to this configuration, since the shape of the unit protrusion 33 expands in the radial direction based on the central axis AX from the tip end 32 side toward the base end 31 side, when a cutting tool T is inserted to cut a position of the unit protrusion 33 away from the workpiece surface 52 in the direction around the central axis AX, interference between the cutting tool T and the unit protrusion 33 can be suppressed. Therefore, a manufacturing method for an acceleration cavity 100 that can be easily manufactured can be provided. [Explanation of symbols]

[0048] 10. Chassis 11,111 Partition 12,112 split plane 20 Cell Section 21 Communication part 30,130 Protrusion 31 Proximal end 32 Tip 33,133 unit protrusion 34 Outer surface 34a Proximal curved part 34b Tip side curved part 34c Connection 34d Connection position 50 Base material 51 Recess 52 Work surface 100, 200 Accelerating cavity AC Accelerator AX Central axis BS Line source L1 First virtual straight line L2 Second virtual straight line M Charged particle S10 Recess forming process S20 Protrusion forming process S30 Joining process T Cutting tool

Claims

1. A housing formed in a joined state of divided members that are cylindrical and have conductivity and are divided into a plurality by a planar dividing surface along a central axis, a plurality of cell portions arranged inside the housing in a state of being aligned in the axial direction of the central axis of the housing and communicated with each other by a communication portion through which charged particles can pass, and a protruding portion disposed inside the housing at a position surrounding the communication portion for each of the cell portions, protruding toward the inside of each of the cell portions in the axial direction, and formed so as to expand in the radial direction with respect to the central axis away from the dividing surface in the axial direction from the tip end side to the base end side. The acceleration cavity is provided with: the protruding portion has a base end side curved portion constituting the base end portion, a tip end side curved portion constituting the tip end portion, and a connecting portion connecting the base end side curved portion and the tip end side curved portion; the connection between the base end side curved portion and the connecting portion and the connection between the tip end side curved portion and the connecting portion are smoothly connected; at a position where a predetermined angle φ is formed from the dividing surface in the circumferential direction of the central axis, the connection position between the tip end side curved portion and the connecting portion is defined as an angle α(φ) between a first virtual straight line perpendicular to the tangent line at the connection position and a second virtual straight line perpendicular to the central axis. When n is a positive real number, α(φ) ∝ (sin φ) n is set to satisfy the above relationship. Acceleration cavity.

2. In a cross-sectional view taken by a plane passing through the central axis, the base end side curved portion is arc-shaped, the connecting portion includes a straight portion, The acceleration cavity according to claim 1.

3. A housing formed in a joined state of divided members that are cylindrical and have conductivity and are divided into a plurality by a planar dividing surface along a central axis, a plurality of cell portions arranged inside the housing in a state of being aligned in the axial direction of the central axis of the housing and communicated with each other by a communication portion through which charged particles can pass, and a protruding portion disposed inside the housing at a position surrounding the communication portion for each of the cell portions and protruding toward the inside of each of the cell portions in the axial direction. A method for manufacturing an acceleration cavity, comprising: a step of forming recesses corresponding to the plurality of cell portions and the communication portion by cutting a machined surface of a base material having a machined surface corresponding to the dividing surface; a step of inserting a cutting tool into the recess from the machined surface side to form a portion corresponding to the protruding portion so as to have a shape that expands in the radial direction with respect to the central axis from the tip end side to the base end side in the axial direction of the central axis. The method includes: In the step of forming a portion corresponding to the protruding portion, a base-end side curved portion constituting the base end portion, a tip-end side curved portion constituting the tip end portion, and a connecting portion connecting the base-end side curved portion and the tip-end side curved portion are provided, the connection between the base-end side curved portion and the connecting portion and the connection between the tip-end side curved portion and the connecting portion are smoothly connected, at a position that is at a predetermined angle φ from the dividing surface in the direction around the central axis, the connection position between the tip-end side curved portion and the connecting portion is defined as the angle α(φ) between a first virtual straight line perpendicular to the tangent line at the connection position and a second virtual straight line perpendicular to the central axis. When n is a positive real number, α(φ) ∝ (sin φ) n is satisfied, a portion corresponding to the protruding portion is formed Method for manufacturing an accelerating cavity.

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