Electron beam generation source, electron beam irradiation device, and x-ray irradiation device

Abstract

An electron beam generating source includes an electron emitting portion extending in a desired axis and emitting electrons, a movable portion connected to one end of the electron emitting portion, a support portion supporting the movable portion in a manner that the movable portion is movable along the axis, and a tension maintaining portion maintaining tension of the electron emitting portion by applying a pressing force or a stretching force to the movable portion. The movable portion and the tension maintaining portion are disposed on the axis, respectively.

Description

TECHNICAL FIELD

[0001] The present application relates to an electron beam generating source, an electron beam irradiation apparatus, and an X-ray irradiation apparatus. BACKGROUND

[0002] In Patent Document 1, a fluorescent display tube is described in which electrons are emitted from an electron emitting portion to a fluorescent body to cause the fluorescent body to emit light. In the electron beam generating source of the fluorescent display tube, a tension of the electron emitting portion is maintained by causing a pressing force of a tension maintaining portion (spring) to act on the linear electron emitting portion.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 8-264138 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the above-described fluorescent display tube, the linear electron emitting portion and the tension maintaining portion are arranged in parallel, and the end portions of both are linked to each other by a linking portion, whereby the pressing force of the tension maintaining portion acts on the electron emitting portion. In such a structure, it is difficult to cause the pressing force of the tension maintaining portion to act on the electron emitting portion along the axis of the electron emitting portion, and sometimes axis deviation of the electron emitting portion occurs due to the action of a moment.

[0008] Therefore, an object of the present application is to provide an electron beam generating source, an electron beam irradiation apparatus, and an X-ray irradiation apparatus in which a pressing force or a tension force of a tension maintaining portion is appropriately applied to an electron emitting portion, thereby suppressing axis deviation of the electron emitting portion.

[0009] METHOD FOR SOLVING THE PROBLEMS

[0010] An electron beam generating source of one embodiment of the present application includes an electron emitting portion which extends in a desired axis and emits electrons, a movable portion which is linked to one end portion of the electron emitting portion, a support portion which supports the movable portion so that the movable portion can move along the axis, and a tension maintaining portion which maintains a tension of the electron emitting portion by applying a pressing force or a tension force to the movable portion, the movable portion and the tension maintaining portion being arranged on the axis, respectively.

[0011] In the electron beam generating source, the electron emission portion, the movable portion, and the tension maintaining portion are provided on the same axis, respectively. Therefore, the electron beam generating source easily causes the pressing force or the stretching force of the tension maintaining portion to act on the electron emission portion via the movable portion in the axial direction. Thus, even in a case where the pressing force or the stretching force of the tension maintaining portion acts, the electron beam generating source can suppress the axis deviation of the electron emission portion. In this way, the electron beam generating source can cause the pressing force or the stretching force of the tension maintaining portion to act on the electron emission portion appropriately, thereby suppressing the axis deviation of the electron emission portion.

[0012] The tension maintaining portion can also apply the pressing force or the stretching force to the movable portion in a manner that the movable portion moves along the axis. In this case, in a case where the pressing force or the stretching force of the tension maintaining portion acts on the electron beam generating source, the electron beam generating source can further suppress the axis deviation of the electron emission portion.

[0013] The movable portion can also be configured in a manner that the center of gravity position of the movable portion is located on the axis. In this case, even in a case where the pressing force or the stretching force of the tension maintaining portion acts, the movable portion can be suppressed from swinging due to the action of the moment. Thus, the electron beam generating source can further suppress the axis deviation of the electron emission portion.

[0014] The electron emission portion and the tension maintaining portion can also be constituted by mutually different members. In this case, the electron beam generating source can suppress the conduction of heat from the electron emission portion to the tension maintaining portion, and can suppress the tension maintaining portion from being heated.

[0015] The support portion can also include a housing portion including an internal space in which the tension maintaining portion is housed. In this case, the electron beam generating source can suppress the tension maintaining portion from being affected by the radiation heat from the electron emission portion, by the housing portion included in the support portion. Thus, the electron beam generating source can suppress the pressing force or the stretching force of the tension maintaining portion from being varied due to the influence of heat and deterioration due to heat, and can stably maintain the tension of the electron emission portion.

[0016] The housing portion can also cover the tension maintaining portion in a manner that the tension maintaining portion is not directly seen from the electron emission portion. In this case, the electron beam generating source can prevent the electrons emitted from the electron emission portion from directly contacting the tension maintaining portion, and can suppress the heating deterioration and damage due to the collision of the electrons.

[0017] The housing portion can also include a movable portion maintaining portion extending along the axis and maintaining the movable portion in a manner that the movable portion can move along the axis. In this case, the housing portion can stably maintain the movable portion in a manner that the movable portion can move, by the movable portion maintaining portion.

[0018] The movable portion holding portion can also be a through-hole that is cylindrical and extends along the axis. In this case, the movable portion can rotate within the through-hole. For example, when the tension holding portion is stretched and contracted, a force in the rotational direction can be applied to the movable portion due to twisting of the tension holding portion. In this case, the force due to the twisting of the movable portion within the through-hole can be concentrated on a portion, thereby maintaining the tension of the electron emitting portion. Thus, even when the tension holding portion is twisted, the electron beam generating source can suppress the influence thereof.

[0019] The electron emitting portion can also be linear. In this case, the electron beam generating source can uniformly irradiate electrons at each position in the axial direction.

[0020] The electron emitting portion can also have a coil-shaped portion that is coil-shaped. In this case, the electron beam generating source can have a function of maintaining the tension of the electron emitting portion.

[0021] The electron beam generating source can further include a frame portion that supports the other end portion of the electron emitting portion and the tension holding portion, respectively. In this case, by being integrated using the frame portion, the processing of the electron beam generating source can be made easy.

[0022] It can also be an electron beam irradiation apparatus including such an electron beam generating source, a main body portion that accommodates the electron beam generating source, and an electron extraction portion for extracting electrons from the electron beam generating source to the outside of the main body portion. In addition, it can also be an X-ray irradiation apparatus including such an electron beam generating source, a main body portion that accommodates the electron beam generating source, an X-ray generating portion that generates X-rays by incident electrons from the electron beam generating source, and an X-ray extraction portion for extracting X-rays to the outside of the main body portion. In this case, an electron beam irradiation apparatus and an X-ray irradiation apparatus that can suppress the axis deviation of the electron emitting portion can be obtained.

[0023] Effects of Invention

[0024] According to the present application, the pressing force or the stretching force of the tension holding portion can be appropriately applied to the electron emitting portion, and the axis deviation of the electron emitting portion can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a perspective view of an electron beam irradiation apparatus according to an embodiment.

[0026] Figure 2 is a partial cross-sectional view showing the internal structure of the electron beam irradiation apparatus of Figure 1 .

[0027] Figure 3 is a cross-sectional view along the III-III line of Figure 1 .

[0028] Figure 4is a perspective view of the filament unit.

[0029] Figure 5 is a cross-sectional view of the filament unit.

[0030] Figure 6 is a cross-sectional perspective view of the tension holding unit.

[0031] Figure 7 is a cross-sectional view of the tension holding unit.

[0032] Figure 8 is a cross-sectional perspective view of the tension holding unit of the first modification.

[0033] Figure 9 is a cross-sectional perspective view of the tension holding unit of the second modification.

[0034] Figure 10 is a cross-sectional perspective view of the tension holding unit of the third modification.

[0035] Figure 11 is a cross-sectional perspective view of the tension holding unit of the fourth modification.

[0036] Figure 12 is a cross-sectional perspective view of the tension holding unit of the fifth modification.

[0037] Figure 13 is a cross-sectional perspective view of the tension holding unit of the sixth modification.

[0038] Figure 14 is a cross-sectional perspective view of the tension holding unit of the seventh modification.

[0039] Figure 15 is a cross-sectional view showing an example of a mounting structure of a filament to a movable body. DETAILED DESCRIPTION

[0040] Hereinafter, an embodiment of the present application will be described with reference to the drawings. In addition, in each drawing, the same or equivalent elements are denoted by the same reference numerals, and overlapping description will be omitted.

[0041] Figure 1 The electron beam irradiation apparatus 1 illustrated is used in order to perform, for example, curing of ink, sterilization, or surface modification of an irradiation target by irradiating the irradiation target with an electron beam EB. Hereinafter, the side on which the electron beam EB is irradiated by the electron beam irradiation apparatus 1, that is, the electron beam exit side (window portion 9 side) will be described as the "front side".

[0042] As Figures 1-3As shown, the electron beam irradiation apparatus 1 includes a filament unit (electron beam generation source) 2, a vacuum vessel (main body portion) 3, a cathode holding member 4, a cathode holding member 5, a rail portion 6, a high voltage introduction insulating member 7, an insulating support member 8, and a window portion (electron extraction portion) 9. The filament unit 2 is an electron beam generation portion that generates an electron beam EB. In addition, the filament unit 2 is an elongated unit.

[0043] The vacuum vessel 3 is formed of an electrically conductive material such as metal. The vacuum vessel 3 is substantially cylindrical. The vacuum vessel 3 forms a substantially cylindrical vacuum space R inside. The filament unit 2 is disposed inside the vacuum vessel 3 along an axis direction (long axis direction) of the substantially cylindrical vacuum space R. An opening portion 3a that communicates the vacuum space R with a space outside is provided at a position on a front side of the filament unit 2 in the vacuum vessel 3. The window portion 9 is fixed in a vacuum-sealed manner with respect to the opening portion 3a.

[0044] The window portion 9 includes a window material 9a and a support body 9b. The window material 9a is formed in a thin film shape. As a material of the window material 9a, a material excellent in electron beam EB permeability (e.g., beryllium, titanium, aluminum, or the like) is used. The support body 9b is disposed at a position on a vacuum space R side of the window material 9a and supports the window material 9a. The support body 9b is a mesh-shaped member having a plurality of holes through which the electron beam EB passes.

[0045] An exhaust port 3b for exhausting air inside the vacuum vessel 3 is provided at a position on a rear side of the filament unit 2 in the vacuum vessel 3. A vacuum pump not shown is connected to the exhaust port 3b, and air inside the vacuum vessel 3 is exhausted by the vacuum pump. Thus, the inside of the vacuum vessel 3 becomes the vacuum space R. An opening portion 3c on the other side and an opening portion 3d on the one side of both ends of the substantially cylindrical vacuum vessel 3 are closed by a flange portion 7a of the high voltage introduction insulating member 7 and a lid portion 3e, respectively.

[0046] A pair of cathode holding members 4 and 5 that become cathode potentials are disposed inside the vacuum vessel 3. Between the cathode holding member 4 on the other side and the cathode holding member 5 on the one side, the rail portion 6 that is a cathode potential and also functions as an enclosing electrode that encloses the filament unit 2 is provided. The rail portion 6 is an electrically conductive and elongated member that is substantially C-shaped in cross section. The rail portion 6 is disposed so that an opening that is substantially C-shaped in cross section faces the front side (window portion 9 side). The rail portion 6 holds the filament unit 2 at an inner side portion (inner side space). For example, the filament unit 2 is inserted into the inner side of the rail portion 6 via insertion holes provided in the cathode holding member 5 and the insulating support member 8 in a state where the lid portion 3e of the vacuum vessel 3 is removed, and thus is held in the rail portion 6.

[0047] A high-voltage introduction insulating member 7 is disposed at one end of the vacuum container 3 on the other side of the opening 3c. The other end of the high-voltage introduction insulating member 7 protrudes outward from the vacuum container 3 via the opening 3c. The high-voltage introduction insulating member 7 has a flange 7a extending radially outward, sealing the opening 3c of the vacuum container 3. The high-voltage introduction insulating member 7 is formed of an insulating material (e.g., an insulating resin such as epoxy resin, ceramic, etc.). The cathode holding member 4 holds one end of the high-voltage introduction insulating member 7 in a state of electrical insulation from the vacuum container 3, which is at ground potential.

[0048] Furthermore, the high-voltage induction insulation component 7 is a high-voltage-resistant connector used to receive a high-voltage supply from an external power supply device of the electron beam irradiation apparatus 1. A high-voltage supply plug (not shown) is inserted into the high-voltage induction insulation component 7. Internal wiring for supplying the externally supplied high voltage to the filament unit 2, etc., is provided inside the high-voltage induction insulation component 7. This internal wiring is covered by the insulating material constituting the high-voltage induction insulation component 7 to ensure insulation from the vacuum container 3.

[0049] An insulating support member 8 is disposed at the end of the opening 3d side (the end of the cover 3e side) on one side of the vacuum container 3. The insulating support member 8 is formed of an insulating material (e.g., an insulating resin such as epoxy resin, ceramic, etc.). The cathode holding member 5 holds the other end of the insulating support member 8 in an electrically insulated state relative to the vacuum container 3.

[0050] like Figures 3-5 As shown, the filament unit 2 is configured as a unit that can be detached from the track section 6. The filament unit 2 includes a filament (electron emitter) 10, a main frame (frame) 11, a grid electrode 12, a sub-frame 13, a power supply line 14, a guide member 15, a terminal holding member 16, a filament fixing member 17, and a tension holding unit 20.

[0051] The main frame 11 is a long strip with a roughly C-shaped cross-section. The main frame 11 is positioned with its roughly C-shaped opening facing forward (towards the window 9). A filament fixing member 17 is provided at one end of the main frame 11, inside the inner space. Additionally, a tension holding unit 20 is provided at one end of the main frame 11, inside the inner space.

[0052] The filament 10 is an electron emitting part that emits electrons as an electron beam EB by being heated by an electric current. The filament 10 is a linear component that extends from one side to the other along a desired axis L. The filament 10 is formed of a high-melting-point metal material, such as a material with tungsten as the main component. One end of the filament 10 is connected to the tension holding unit 20. The other end of the filament 10 is connected to the filament fixing member 17. In this way, the main frame 11 supports the tension holding unit 20 connected to one end of the filament 10 and the filament fixing member 17 connected to the other end of the filament 10, respectively.

[0053] Terminal holding member 16 is mounted at the other end of the main frame 11. Terminal holding member 16 holds, in an electrically insulated manner, the filament terminal T1 supplying current for electron emission from the filament 10, the high-voltage terminal T2 supplying cathode potential to the filament unit 2, and the grid electrode terminal T3 supplying applied voltage to the grid electrode 12. Filament terminal T1 is connected to the other end of the power supply line 14. High-voltage terminal T2 is electrically connected to filament fixing member 17.

[0054] The sub-frame 13 is a long strip with a roughly U-shaped cross-section. The sub-frame 13 is arranged parallel to the main frame 11. The power supply line 14 connects to the tension holding unit 20 through the inner side (inner space) of the sub-frame 13 from the connection point with the filament terminal T1. The sub-frame 13 provides protection for the power supply line 14. The main frame 11 and the sub-frame 13 are interconnected by multiple guide members 15. The outer surface of the guide members 15 slides against the inner surface of the track section 6.

[0055] The grid electrode 12 is disposed on the front side of the filament 10 and is supported by the guide member 15 across the insulating member 18. Multiple holes are formed on the grid electrode 12 (see reference). Figure 4 (etc.). The grid electrode 12 is electrically connected to the grid electrode terminal T3 via wiring not shown.

[0056] The tension holding unit 20 maintains the tension of the filament 10. Here, the tension holding unit 20 maintains the tension of the filament 10 by pressing or stretching a movable body connected to one end of the filament 10 using a spring. In this embodiment, the tension holding unit 20 maintains the tension of the filament 10 by stretching the movable body using a spring. The tension holding unit 20 is mounted to the main frame 11 in a state of electrical insulation from the main frame 11 via an insulating member or the like. One end of a power supply line 14 is connected to the tension holding unit 20. The tension holding unit 20 can supply power to the filament 10 via the power supply line 14 while maintaining the tension of the filament 10.

[0057] Starting from the end where the filament unit 2 is provided (such as the end with the filament terminal T1), it is inserted and fixed inside the track section 6 (inner space) via the insertion holes provided in the cathode holding member 5 and the insulating support member 8. When the filament unit 2 is fully inserted, the front ends of the filament terminal T1, the high-voltage terminal T2, and the grid electrode terminal T3 respectively abut against the front ends of the three connecting terminals provided in the high-voltage induction insulating member 7. Thus, the filament terminal T1, etc., are electrically connected to the connecting terminals provided in the high-voltage induction insulating member 7.

[0058] When the filament 10 is heated by an electric current, it emits electrons by being subjected to a high negative voltage, ranging from tens to hundreds of kV. A predetermined voltage is applied to the grid electrode 12. For example, a voltage 100V to 150V more positive than the negative voltage applied to the filament 10 can be applied to the grid electrode 12. The grid electrode 12 forms an electric field for attracting electrons and suppressing diffusion. As a result, electrons emitted from the filament 10 exit forward as an electron beam EB through the holes provided in the grid electrode 12.

[0059] Next, use Figure 6 and Figure 7 The tension holding unit 20, which maintains the tension of the filament 10, will be described in detail below. For ease of explanation, the side (or side) where the filament 10 is located relative to the tension holding unit 20 will be designated "left side," and the side (or side) where the tension holding unit 20 is located relative to the filament 10 will be designated "right side." That is, the left-right direction refers to the direction along the axis L extending from one side to the other.

[0060] like Figure 6 and Figure 7 As shown, the tension holding unit 20 includes a movable body (movable part) 21, a housing (support part, housing part) 22, a spring (tension holding part) 23, and a foil (power supply path part) 24. The movable body 21 is connected to one end of the filament 10. The movable body 21 has a cylindrical part 21a and a connecting part 21b. The cylindrical part 21a is cylindrical and extends in the left-right direction. One end of the filament 10 is fixed to the left end of the cylindrical part 21a. Various methods can be used to fix the cylindrical part 21a to the filament 10. The connecting part 21b is connected to the right end of the cylindrical part 21a. The other end of the spring 23 and the other end of the foil 24 are respectively connected to the connecting part 21b. The movable body 21 is formed of a conductive material. The movable body 21 is formed of materials such as stainless steel, copper, or copper alloy.

[0061] The movable body 21 is disposed on the axis L. Further, the movable body 21 being disposed on the axis L means that, when viewed from the direction along the axis L, the axis L is located inside the outer edge of the movable body 21 in the configuration state. The same applies to other components being disposed on the axis L. In addition, the movable body 21 can be configured so that the center of gravity of the movable body 21 is located on the axis L.

[0062] The housing 22 is a case body having an accommodation space (an internal space) S inside. The spring 23, the foil 24, and the right end portion of the movable body 21 are accommodated in the accommodation space S of the housing 22. The housing 22 can also be composed of a case portion 22a having one side open and a lid portion 22b covering the open portion of the case portion 22a, so that the spring 23 and the like can be accommodated in the accommodation space S. A wall portion on the side of the filament 10 (the other side) in the housing 22, that is, a filament-side wall portion 22c (constituting a wall portion on the left side of the housing 22) is provided with a guide hole (a movable portion holding portion) 22d. The guide hole 22d extends along the axis L. In addition, the guide hole 22d is a through-hole in a cylindrical shape extending along the axis L. The diameter of the guide hole 22d is larger than the diameter of the cylindrical portion 21a of the movable body 21 by a desired value. The guide hole 22d guides the cylindrical portion 21a of the movable body 21 so as to be movable along the axis L. That is, the housing 22 holds the movable portion 21 by the guide hole 22d so that the movable body 21 is movable along the axis L.

[0063] A wall portion on the side opposite to the side of the filament 10 (the one side) in the housing 22, that is, a power supply-side wall portion 22e (constituting a wall portion on the right side of the housing 22) is provided with a power supply wire connecting portion 22f to which one end portion of the power supply wire 14 is connected. For example, the end portion of the power supply wire 14 is electrically connected to the housing 22 by a bolt at the power supply wire connecting portion 22f. Thus, the housing 22 is electrically connected to a power supply device (a power supply device) that supplies power to the filament 10 via the power supply wire 14 and the like. The housing 22 is formed of an electrically conductive material. The housing 22 is formed of, for example, a material such as stainless steel, copper, a copper alloy, or the like.

[0064] The spring 23 is accommodated in the accommodation space S of the housing 22. The spring 23 is disposed on the axis L. The other end portion of the spring 23 is joined to the end portion on the right side of the connecting portion 21b. The joining position of the spring 23 to the connecting portion 21b is located on the axis L. One end portion of the spring 23 is joined to the power supply-side wall portion 22e of the housing 22. The housing 22 covers the spring 23 so that the spring 23 is not directly visible from the filament 10. The joining position (a connecting portion) of the spring 23 to the movable body 21 is located inside the accommodation space S.

[0065] The spring 23 is a tensile spring. The spring 23 exerts a tensile force on the movable body 21 in a manner to move the movable body 21 along the axis L. That is, the spring 23 stretches the movable body 21 from the linking position with the movable body 21 to the side direction along the axis L. The movable body 21 links one end of the filament 10 with the other end of the spring 23. Thereby, the spring 23 stretches the filament 10 via the movable body 21 by exerting a tensile force on the movable body 21, and maintains the tension of the filament 10. The spring 23 is formed of, for example, stainless steel, Inconel, or the like. The spring 23 can be formed of a material different from the filament 10. The load of the spring 23 needs to be in a desired range at the time of operation (when the filament 10 is energized), and if it deviates from the range, there is a possibility that the filament 10 is relaxed, or plastically deformed, or broken, or the like. Therefore, if the load of the spring 23 is set to Fa, the allowable tensile load of the filament 10 is set to Fx, and the total of the weight and the friction of the movable body 21 is set to Fy, the relation Fx + Fy > Fa needs to be satisfied. Further, by the heating of the filament 10 by energization, the allowable tensile load of the filament 10 at normal temperature Fxl > the allowable tensile load of the filament 10 at the time of heating Fx2, and therefore attention needs to be paid. Therefore, the load of the spring 23 is preferably in the range of 0.01 N to 1000 N, more preferably 0.01 N to 100 N, and further preferably in the range of 0.1 N to 10 N.

[0066] The foil 24 is housed in the housing 22. The foil 24 becomes a power supply path that supplies the power supplied to the housing 22 via the power supply line 14 to the movable body 21. One end of the foil 24 is connected to the power supply side wall portion 22e of the housing 22, and the other end is connected to the connecting portion 21b of the movable body 21. The connecting portion of the foil 24 to the movable body 21 is located inside the housing space S. Thereby, the foil 24 is electrically connected to the filament 10 via the movable body 21. The foil 24 is formed of a material having a higher electrical conductivity than the spring 23. That is, the electrical resistance value of the spring 23 is larger than that of the foil 24. The foil 24 is formed of, for example, copper or the like as a material having a good electrical conductivity and a good flexibility. For example, the electrical resistance of the spring 23 formed of stainless steel is about 6 Ω. For example, copper is used as the material of the foil 24, and the length thereof is set to 50 mm, for example. The specific resistance of copper is 1.7 x 10 -2 mm 2 Therefore, if the cross-sectional area of the foil 24 is set to 1.4 x 10

[0067] The foil 24 is a thin film component (metal film portion) formed of metal. The thickness of the foil 24 is thinner than its width, and the width of the foil 24 is smaller than its length. The foil 24 extends from the power supply sidewall 22e toward the movable body 21 and is fixed to the connecting portion 21b in a U-shaped state at its front end. Thus, the foil 24 has a U-shaped folded-back portion 24a, and at its left end, it includes an overlapping (double-layered) area as a positional relationship along the axis L, and this area is separated from each other in a direction perpendicular to the axis L. Therefore, the length of the foil 24 is longer than that of the spring 23 and longer than the length (straight line length) from the connection position A between the foil 24 and the power supply sidewall 22e to the connection position B between the foil 24 and the movable body 21. Therefore, even when the movable body 21 moves along the axis L, the foil 24 can allow the movable body 21 to move by moving the position of the folded portion 24a in the foil 24 (making the double area larger or smaller), and maintain the state of connection between the power supply side wall portion 22e and the movable body 21.

[0068] like Figure 7 As shown, the housing 22 may also include a partition 22g with one end fixed to the power supply side wall 22e and the other end extending toward the movable body 21. When separated from the spring 23, the partition 22g extends to a position to the left of the left end of the spring 23, thus separating the spring 23 and the foil 24. This prevents the foil 24 from contacting the spring 23.

[0069] Thus, in the tension holding unit 20, the tension of the filament 10 can be maintained by the tensile force of the spring 23. Furthermore, the length (free length) of the spring 23 is such that even if the filament 10 becomes longer due to thermal expansion, a tensile force can still be applied to the movable body 21. For example, if the material constituting the filament 10 is tungsten, and if a 500mm long filament 10 is heated to 2000°C, then if the coefficient of linear expansion of tungsten is set to 5.2 × 10⁻⁶... -6 At [1 / K] (2000℃), the filament 10 will lengthen by approximately 5 mm due to thermal expansion. Therefore, in order to absorb the amount of thermal expansion of the filament 10, the movable body 21 needs to be able to move by at least 5 mm. Furthermore, it is preferable to also ensure that the range of movement of peripheral components (such as the main frame 11) due to thermal expansion is taken into account. Thus, even if the length of the filament 10 changes due to thermal expansion, the tension holding unit 20 can maintain the tension of the filament 10 by the tensioning force of the spring 23. In this way, the filament 10 is kept in a stretched straight state by the tension holding unit 20.

[0070] Further, in the tension maintaining unit 20, the power supply side wall portion 22e to which the power supply line 14 is connected and the movable body 21 to which the filament 10 is connected are connected by the spring 23 and the foil 24, respectively. Here, the foil 24 is formed of a material having higher conductivity than the spring 23. Thus, the power supply from the power supply side wall portion 22e to the movable body 21 is mainly performed by the foil 24, not by the spring 23. Thus, the heating of the spring 23 caused by the energization is suppressed, and the variation or deterioration of the tension force of the spring 23 due to the influence of the heat is suppressed. In this way, the tension maintaining unit 20 can supply the power to the filament 10 via the movable body 21 using the foil 24 while maintaining the tension of the filament 10 using the spring 23. More specifically, the power supply to the filament 10 is performed via the movable body 21, and thus the friction or the like caused by the mechanical sliding action of the spring 23 is borne by the movable body 21, so that the mechanical damage to the filament 10 can be suppressed, and the influence of the spring 23 on the maintenance of the tension of the filament 10 and the power supply from the foil 24 to the filament 10 can be suppressed.

[0071] As described above, in the electron beam irradiation apparatus 1 (filament unit 2), the filament 10, the movable body 21, and the spring 23 are disposed on the same axis L, respectively. Thus, the electron beam irradiation apparatus 1 can easily cause the tension force of the spring 23 to act on the filament 10 in the direction of the axis L via the movable body 21. Thus, even in the case where the tension force of the spring 23 acts, the axis deviation (deviation from the axis L) of the filament 10 can be suppressed. In this way, the electron beam irradiation apparatus 1 can cause the tension force of the spring 23 to act on the filament 10 appropriately, thereby suppressing the axis deviation of the filament 10. As a result, a more uniform electron emission distribution can be obtained.

[0072] The spring 23 applies the tension force to the movable body 21 in such a manner that the movable body 21 moves along the axis L. In this case, the electron beam irradiation apparatus 1 can further suppress the axis deviation of the filament 10 in the case where the tension force of the spring 23 acts.

[0073] In the case where the movable body 21 is configured such that the center of gravity thereof is located on the axis L, even in the case where the tension force of the spring 23 acts, the movable body 21 can be suppressed from swinging due to the action of the moment. Thus, the electron beam irradiation apparatus 1 can further suppress the axis deviation of the filament 10.

[0074] Since the filament 10 and the spring 23 are formed of different members, the electron beam irradiation apparatus 1 can suppress the conduction of the heat from the filament 10 to the spring 23, and thus can suppress the heating of the spring 23.

[0075] The spring 23 is housed in the housing space S of the housing 22. In this case, the electron beam irradiation apparatus 1 can suppress the spring 23 from being affected by the radiant heat from the filament 10. Thus, the electron beam irradiation apparatus 1 can suppress the variation in the tension force of the spring 23 due to the effect of heat and the deterioration due to heat, and can stably maintain the tension of the filament 10.

[0076] The housing 22 covers the spring 23 so that the spring 23 is not directly seen from the filament 10. In this case, the electron beam irradiation apparatus 1 can prevent the electrons emitted from the filament 10 from directly hitting the spring 23, and can suppress the heating deterioration and damage due to the collision of the electrons.

[0077] The housing 22 is provided with a guide hole 22d that extends along the axis L and holds the movable body 21 in such a manner that the movable body 21 can move along the axis L. In this case, the housing 22 can stably hold the movable body 21 in such a manner that the movable body 21 can move, by the guide hole 22d.

[0078] The guide hole 22d is a through-hole that is cylindrical and extends along the axis L. In this case, the movable body 21 can rotate within the guide hole 22d. Thus, the tension holding unit 20 can suppress the concentration of the force due to the rotation of the movable body 21 within the guide hole 22d even when the spring 23 exerts a force in the rotational direction on the movable body 21 due to the twisting of the spring 23 when the spring 23 is stretched or contracted, and can maintain the tension of the filament 10. Thus, the electron beam irradiation apparatus 1 can suppress the effect even when the spring 23 is twisted.

[0079] The filament 10 is in a straight line state by the tension maintained by the tension holding unit 20. In this case, the electron beam irradiation apparatus 1 can uniformly irradiate electrons at each position in the axis L direction.

[0080] The filament unit 2 includes the main frame 11 that holds the tension holding unit 20 to which one end of the filament 10 is connected and the filament fixing member 17 to which the other end of the filament 10 is connected. In this case, the filament unit 2 can be easily handled by being integrated with the main frame 11. In addition, since the filament unit 2 can be attached to and detached from the track portion 6 of the electron beam irradiation apparatus 1, the filament 10 and the tension holding unit 20 can be attached to and detached from the track portion 6 of the electron beam irradiation apparatus 1 together with the filament unit 2.

[0081] Next, various modified examples of the tension holding unit provided in the electron beam irradiation apparatus 1 will be described. Hereinafter, the description will be made focusing on the points different from the tension holding unit 20 in the above-described embodiment and the points different from the tension holding unit in each modified example.

[0082] (First Modified Example)

[0083] As Figure 8 shown, the tension holding unit 20A in the first modified example includes the movable body 21A, the case 22A, the spring 23, and the annular elastic body (power supply path portion) 25. The movable body 21A is in a cylindrical shape extending in the left-right direction. One end portion of the filament 10 is fixed to the left side end portion of the movable body 21A. The other end portion of the spring 23 is joined to the right side end portion of the movable body 21A. The movable body 21A is disposed on the axis L. In addition, the movable body 21A is disposed in such a manner that the center of gravity position of the movable body 21A is located on the axis L. The movable body 21A is formed of an electrically conductive material. The movable body 21A is formed of, for example, a copper alloy, stainless steel, or the like, which is a material having good electrical conductivity.

[0084] The case 22A is a box having a housing space S inside. The spring 23 is housed in the housing space S of the case 22A. The case 22A can also be configured by a box portion 22a having one side open, so that the spring 23 can be housed in the housing space S. A guide hole 22d is provided in the filament side wall portion 22c of the case 22A. The diameter of the guide hole 22d is larger than the diameter of the movable body 21A by a desired value. The length of the guide hole 22d in the axis L direction is longer than the length of the movable body 21A. The guide hole 22d guides the movable body 21A so as to be movable along the axis L. That is, the case 22A holds the movable body 21A in such a manner that the movable body 21A is movable along the axis L, by the guide hole 22d. The case 22A is formed of an electrically conductive material. The case 22A is formed of, for example, a copper alloy, stainless steel, or the like, which is a material having good electrical conductivity.

[0085] The spring 23 is disposed on the axis L. The other end portion of the spring 23 is joined to the right side end portion of the movable body 21A. The joining position of the spring 23 to the movable body 21A is located on the axis L. One end portion of the spring 23 is joined to the power supply side wall portion 22e of the case 22A. The case 22A covers the spring 23 so that the spring 23 is not directly visible from the filament 10.

[0086] The spring 23 applies a tensile force to the movable body 21A in such a manner that the movable body 21A is movable along the axis L. That is, the spring 23 stretches the movable body 21A from the joining position to the side direction along the axis L. Thus, the spring 23 stretches the filament 10 via the movable body 21A by applying a tensile force to the movable body 21A, and holds the tension of the filament 10.

[0087] The annular elastic body 25 is housed in the guide hole 22d of the housing 22A. The annular elastic body 25 becomes a power supply path that supplies the electric power supplied to the housing 22A via the power supply line 14 to the movable body 21A. The annular elastic body 25 is composed of an elastic member that is formed in an annular shape and has electric conductivity. The annular elastic body 25 is embedded in the recessed portion 21c of the movable body 21A that extends over the entire region of the outer peripheral surface in the cross section in the direction that intersects perpendicularly with the axis L.

[0088] A portion (one end portion) of the outer peripheral edge of the annular elastic body 25 in the radial direction (the direction that intersects perpendicularly with the axis L) abuts on and is electrically connected to the inner peripheral surface of the guide hole 22d of the housing 22A. A portion (the other end portion) of the inner peripheral edge of the annular elastic body 25 abuts on and is electrically connected to the outer peripheral surface (the inner wall surface of the recessed portion 21c) of the movable body 21A. That is, the annular elastic body 25, in the state of being embedded in the recessed portion 21c, has a diameter of the outer periphery that is larger than a diameter of the outer periphery of the movable body 21A and has a diameter of the inner periphery that is at least smaller than the diameter of the outer periphery of the movable body 21A. Thus, the annular elastic body 25 is electrically connected to the housing 22A and is electrically connected to the filament 10 via the movable body 21A. The annular elastic body 25 is formed of a material that has electric conductivity better than the spring 23. That is, the spring 23 has a larger electric resistance value than the annular elastic body 25. The annular elastic body 25 is formed of, for example, a copper alloy or the like that is a material having good electric conductivity.

[0089] Thus, in the tension retaining unit 20A as well, as in the tension retaining unit 20 in the embodiment, the tension of the filament 10 can be maintained by the tension force of the spring 23. In addition, in the tension retaining unit 20A, the housing 22A and the movable body 21A are connected by the spring 23 and the annular elastic body 25, respectively. In addition, the annular elastic body 25 is formed of a material that has electric conductivity better than the spring 23. Thus, the electric power is supplied from the housing 22A to the movable body 21A not by the spring 23 but mainly by the annular elastic body 25. Thus, the heating of the spring 23 caused by the energization is suppressed, and the variation or deterioration of the tension force of the spring 23 due to the influence of the heat is suppressed. Thus, the tension retaining unit 20A can supply the electric power to the filament 10 via the movable body 21A by the annular elastic body 25 while retaining the tension of the filament 10 by the spring 23.

[0090] As described above, the electron beam irradiation apparatus 1 can exert the same effects as in the case where the tension retaining unit 20 in the embodiment is included even in the case where the tension retaining unit 20A is included.

[0091] (Second Modified Example)

[0092] As Figure 9As shown, the tension holding unit 20B in the second modified example includes the movable body 21B, the housing 22B, the spring (tension holding portion) 26, and the foil (power supply path portion) 27. The movable body 21B is linked to one end of the filament 10. The movable body 21B has a cylindrical portion 21a and a small-diameter cylindrical portion 21d. The small-diameter cylindrical portion 21d includes a main body portion 21d1 having a smaller diameter than the cylindrical portion 21a and a front end portion 21d2 having a smaller diameter than the main body portion 21d1. The main body portion 21d1 is linked to the left side end of the cylindrical portion 21a, and the front end portion 21d2 is linked to the left side end of the main body portion 21d1. One end of the filament 10 is fixed to the left side end of the front end portion 21d2 of the small-diameter cylindrical portion 21d. The movable body 21B is disposed on the axis L. In addition, the movable body 21B is disposed in such a manner that the center of gravity of the movable body 21B is located on the axis L. The movable body 21B is formed of an electrically conductive material. The movable body 21B is formed of, for example, stainless steel, copper, copper alloy, or the like.

[0093] The housing 22B further includes a housing spring receiving portion (housing tension receiving portion) 22h with respect to the housing 22A (refer to Figure 8 ) in the first modified example. The housing spring receiving portion 22h is provided to the surface of the filament 10 side (the other side) of the filament side wall portion 22c. A small-diameter hole 22j through which the front end portion 21d2 of the small-diameter cylindrical portion 21d of the movable body 21B can be inserted is provided in the housing spring receiving portion 22h. The diameter of the small-diameter hole 22j is smaller than the diameter of the guide hole 22d and larger than the diameter of the front end portion 21d2. The housing 22B is formed of an electrically conductive material. The housing 22B is formed of, for example, stainless steel, copper, copper alloy, or the like.

[0094] The spring 26 is housed in the guide hole 22d of the housing 22B. The spring 26 is disposed on the axis L. The main body portion 21d1 of the small-diameter cylindrical portion 21d of the movable body 21B passes through the inside of the spring 26. That is, the outer diameter of the spring 26 is smaller than the inner diameter of the guide hole 22d, and the inner diameter of the spring 26 is larger than the outer diameter of the main body portion 21d1 of the small-diameter cylindrical portion 21d. One end of the spring 26 abuts against the left side end surface of the cylindrical portion 21a of the movable body 21B. The other end of the spring 26 abuts against the right side surface of the housing spring receiving portion 22h. That is, the left side end surface of the cylindrical portion 21a in the movable body 21B becomes a movable body spring receiving portion (movable body tension receiving portion) 21e to which the spring 26 abuts. The housing spring receiving portion 22h is located at a position closer to the filament 10 side than the movable body spring receiving portion 21e. The spring 26 is disposed between the movable body spring receiving portion 21e and the housing spring receiving portion 22h. The housing spring receiving portion 22h covers the spring 26 so that the spring 26 cannot be directly seen from the filament 10 (the filament 10 and the spring 26 are divided).

[0095] The spring 26 is a compression spring. The spring 26 exerts a pressing force on the movable body 21B in a manner to move the movable body 21B along the axis L. That is, the spring 26 presses the movable body 21B in one side direction along the axis L from the abutting position with the movable body 21B. The movable body 21B is linked to one end portion of the filament 10. Thus, the spring 26 stretches the filament 10 in the right direction via the movable body 21B by exerting a pressing force on the movable body 21B, and maintains the tension of the filament 10. The spring 26 is formed of, for example, stainless steel, Inconel, or the like. The spring 26 can be formed of a material different from the filament 10.

[0096] The foil 27 is housed in the housing space S of the housing 22B. The foil 27 becomes a power supply path that supplies the power supplied to the housing 22B via the power supply line 14 to the movable body 21B. One end portion of the foil 27 is connected to the power supply side wall portion 22e of the housing 22B, and the other end portion is connected to the cylindrical portion 21a of the movable body 21B. Thus, the foil 27 is electrically connected to the filament 10 via the movable body 21B. The foil 27 is formed of a material having higher electrical conductivity than the spring 26. That is, the resistance value of the spring 26 is larger than that of the foil 27. The foil 27 is formed of, for example, copper or the like as a material having good electrical conductivity and good bendability.

[0097] The foil 27 is a thin film-like member (metal thin film portion) formed of a metal. The thickness of the foil 27 is thinner than the width of the foil 27, and the width of the foil 27 is smaller than the length of the foil 27. The length of the foil 27 is longer than the length (the length of a straight line along the axis L) from the connection position A of the foil 27 to the power supply side wall portion 22e to the connection position B of the foil 27 to the movable body 21B. Thus, even in the case where the movable body 21B moves along the axis L, the foil 24 can allow the movement of the movable body 21B, and maintain the state where the power supply side wall portion 22e is connected to the movable body 21B.

[0098] Thus, in the tension maintaining unit 20B, the tension of the filament 10 can be maintained by the pressing force of the spring 26. In addition, the length (free length) of the spring 26 becomes a length that can exert a pressing force on the movable body 21B even in the case where the length of the filament 10 is increased due to thermal expansion. Thus, the tension maintaining unit 20B can maintain the tension of the filament 10 by the pressing force of the spring 26 even in the case where the length of the filament 10 is changed due to thermal expansion. Thus, the filament 10 is maintained in a state of being stretched in a straight line by the tension maintaining unit 20B.

[0099] Further, in the tension holding unit 20B, the housing 22B and the movable body 21B are connected by the spring 26 and the foil 27, respectively. Here, the foil 27 is formed of a material having higher conductivity than the spring 26. Thus, the movable body 21B is supplied with electric power from the power supply side wall portion 22e not by the spring 26 but mainly by the foil 27. Thus, heating of the spring 26 caused by energization is suppressed, and variation in pressing force of the spring 26 due to the influence of heat and the like is suppressed. In this way, the tension holding unit 20B can supply electric power to the filament 10 via the movable body 21B using the foil 27 while holding the tension of the filament 10 using the spring 26.

[0100] As described above, the electron beam irradiation apparatus 1 can exert the same effects as the case where the tension holding unit 20 of the embodiment is included, even in the case where the tension holding unit 20B is included.

[0101] Specifically, in the electron beam irradiation apparatus 1 (filament unit 2) including the tension holding unit 20B, the filament 10, the movable body 21B, and the spring 26 are disposed on the same axis L, respectively. Thus, the electron beam irradiation apparatus 1 can easily cause the pressing force of the spring 26 to act on the filament 10 via the movable body 21B in the direction of the axis L. Thus, even in the case where the pressing force of the spring 26 acts, the axial deviation (deviation from the axis L) of the filament 10 can be suppressed. In this way, the electron beam irradiation apparatus 1 including the tension holding unit 20B can cause the pressing force of the spring 26 to act on the filament 10 appropriately, thereby suppressing the axial deviation of the filament 10. As a result, a more uniform electron emission distribution can be obtained.

[0102] The spring 26 exerts the pressing force on the movable body 21B in such a manner that the movable body 21B moves along the axis L. In this case, the electron beam irradiation apparatus 1 including the tension holding unit 20B can further suppress the axial deviation of the filament 10 in the case where the pressing force of the spring 26 acts.

[0103] The movable body 21B is disposed in such a manner that the center of gravity position of the movable body 21B is located on the axis L. In this case, even in the case where the pressing force of the spring 26 acts, the movable body 21B can be suppressed from swinging due to the action of the moment. Thus, the electron beam irradiation apparatus 1 including the tension holding unit 20B can further suppress the axial deviation of the filament 10.

[0104] The filament 10 and the spring 26 are formed of different members, respectively. In this case, the electron beam irradiation apparatus 1 including the tension holding unit 20B can suppress the conduction of heat from the filament 10 to the spring 26, and can suppress the spring 26 from being heated.

[0105] The spring 26 is housed in the guide hole 22d of the housing 22B. In this case, the electron beam irradiation apparatus 1 including the tension retaining unit 20B can suppress the spring 26 from being affected by the radiant heat from the filament 10. Thus, the electron beam irradiation apparatus 1 including the tension retaining unit 20B can suppress the pressing force of the spring 26 from fluctuating due to the effect of heat and deterioration due to heat, and can stably retain the tension of the filament 10.

[0106] The small-diameter hole 22j provided in the housing spring receiving portion 22h has a diameter smaller than that of the guide hole 22d, and has a diameter to the extent that the small-diameter cylindrical portion 21d passes through. In addition, the housing spring receiving portion 22h covers the spring 26 so that the spring 26 is not directly visible from the filament 10. In this case, the electron beam irradiation apparatus 1 including the tension retaining unit 20B can prevent the electrons emitted from the filament 10 from directly hitting the spring 26, and can suppress heating deterioration and damage due to the collision of the electrons.

[0107] (Third Modification)

[0108] As shown in FIG. 8, the tension retaining unit 20C in the third modification is configured to replace the foil 27 in the structure of the tension retaining unit 20B (refer to FIG. 6) in the second modification with the annular elastic body 25 of the tension retaining unit 20A (refer to FIG. 3) in the first modification. Specifically, the tension retaining unit 20C includes the movable body 21C, the housing 22B, the annular elastic body (power supply path portion) 25, and the spring 26. The recess 21c is provided on the outer peripheral surface of the cylindrical portion 21a of the movable body 21C. The annular elastic body 25 is fitted in the recess 21c of the cylindrical portion 21a. Figure 10 Figure 8 In the tension retaining unit 20C, the tension of the filament 10 can be maintained by the pressing force of the spring 26, as with the tension retaining unit 20B in the second modification. In addition, in the tension retaining unit 20C, the housing 22B and the movable body 21C are connected by the annular elastic body 25 and the spring 26, respectively. Here, the annular elastic body 25 is formed of a material having a higher conductivity than the spring 26. Thus, the power supply from the housing 22B to the movable body 21C is mainly performed by the annular elastic body 25, rather than by the spring 26. Thus, the heating of the spring 26 due to the passage of current is suppressed, and the fluctuation of the pressing force of the spring 26 due to the effect of heat and the like is suppressed. In this way, the tension retaining unit 20C can supply power to the filament 10 via the movable body 21C using the annular elastic body 25, while retaining the tension of the filament 10 using the spring 26. Figure 9

[0109] In the tension retaining unit 20C, the tension of the filament 10 can be maintained by the pressing force of the spring 26, as with the tension retaining unit 20B in the second modification. In addition, in the tension retaining unit 20C, the housing 22B and the movable body 21C are connected by the annular elastic body 25 and the spring 26, respectively. Here, the annular elastic body 25 is formed of a material having a higher conductivity than the spring 26. Thus, the power supply from the housing 22B to the movable body 21C is mainly performed by the annular elastic body 25, rather than by the spring 26. Thus, the heating of the spring 26 due to the passage of current is suppressed, and the fluctuation of the pressing force of the spring 26 due to the effect of heat and the like is suppressed. In this way, the tension retaining unit 20C can supply power to the filament 10 via the movable body 21C using the annular elastic body 25, while retaining the tension of the filament 10 using the spring 26.

[0110] ​​As described above, the electron beam irradiation apparatus 1 can achieve the same effects as in the case where the tension holding unit 20B of the second modified example is included, even in the case where the tension holding unit 20C is included.

[0111] (4th Modified Example)

[0112] As Figure 11 shown, the tension holding unit 20D of the fourth modified example further includes an insulating ring (insulating member) 28 and an insulating ring (insulating member) 29, in addition to the structure of the tension holding unit 20B of the second modified example (see Figure 9 ).

[0113] The insulating ring 28 is disposed between the spring 26 and the housing spring receiving portion 22h. The insulating ring 28 electrically insulates the housing 22B from the spring 26. The insulating ring 28 is formed of a material having a lower electrical conductivity than the spring 26. The outer edge portion of the insulating ring 28 protrudes toward the spring 26 side in the direction along the axis L in a manner so as to surround the outer peripheral portion of the spring 26. Thereby, the insulating ring 28 can prevent the outer peripheral portion of the spring 26 from abutting against the inner peripheral surface of the guide hole 22d. In addition, positioning in the direction perpendicular to the axis L of the spring 26 is also performed by the inner peripheral portion of the insulating ring 28, so the contact of the spring 26 with the small-diameter cylindrical portion 21d of the movable body 21B is also suppressed.

[0114] Similarly, the insulating ring 29 is disposed between the movable body spring receiving portion 21e of the cylindrical portion 21a of the movable body 21B and the spring 26. The insulating ring 29 electrically insulates the movable body 21B from the spring 26. The insulating ring 29 is formed of a material having a lower electrical conductivity than the spring 26. The outer edge portion of the insulating ring 29 protrudes toward the spring 26 side in the direction along the axis L in a manner so as to surround the outer peripheral portion of the spring 26. Thereby, the insulating ring 29 can prevent the outer peripheral portion of the spring 26 from abutting against the inner peripheral surface of the guide hole 22d. In addition, positioning in the direction perpendicular to the axis L of the spring 26 is also performed by the inner peripheral portion of the insulating ring 29, so the contact of the spring 26 with the small-diameter cylindrical portion 21d of the movable body 21B is also suppressed.

[0115] Further, the tension holding unit 20D can also be a structure including either one of the insulating ring 28 and the insulating ring 29 alone.

[0116] As described above, in the tension holding unit 20D of the fourth modified example, by including the insulating rings 28 and 29, the flow of current to the spring 26 can be further suppressed. Thereby, the tension holding unit 20D can further suppress the heating of the spring 26 caused by the passage of current.

[0117] (5th Modified Example)

[0118] AsFigure 12 As shown, the tension holding unit 20E in the fifth modification is different from the tension holding unit 20C in the third modification (see reference). Figure 10 The structure also includes insulating rings (insulating components) 28 and 29. That is, the tension holding unit 20E includes a movable body 21C, a housing 22B, an annular elastic body 25, a spring 26, insulating rings 28 and 29. Insulating rings 28 and 29 have the same structure as those in the fourth variation.

[0119] As described above, in the tension holding unit 20E of the fifth modification, the inclusion of insulating rings 28 and 29 further suppresses current flow to the spring 26. Therefore, the tension holding unit 20E can further suppress the heating of the spring 26 caused by energization.

[0120] Here, for example, when using Figure 6 and Figure 7 In the tension holding unit 20 of the described embodiment, current to the spring 23 can also be further suppressed. Specifically, Figure 6 and Figure 7 The portion of the tension holding unit 20 shown, where the spring 23 is connected (the hooked portion), can also be made of an insulating material (e.g., ceramic). Alternatively, an insulating coating can be applied to the portion of the connection 21b connected to the spring 23. Furthermore, an insulating coating can also be applied to the spring 23 of the tension holding unit 20. Similarly, for example, using... Figure 8 In the first modified example described, the portion of the movable body 21A of the tension holding unit 20A that connects to the spring 23 (the hook portion) can also be made of an insulating material (e.g., ceramic). Alternatively, an insulating coating can be applied to the portion of the movable body 21A connected to the spring 23. Furthermore, an insulating coating can also be applied to the spring 23 of the tension holding unit 20A. Even in these cases, the tension holding units 20 and 20A can further suppress current to the spring 23, thereby further suppressing the heating of the spring 23 caused by energization.

[0121] (Sixth variation)

[0122] like Figure 13 As shown, the tension holding unit 20F in the sixth variation is formed by dividing the housing 22 of the tension holding unit 20 in the embodiment into two parts. Specifically, the tension holding unit 20F includes a movable body 21, a housing 22F, a spring 23, and a foil 24. The housing 22F includes a first housing portion 22k and a second housing portion 22m.

[0123] The first housing portion 22k has a guide hole 22d through which the cylindrical portion 21a of the movable body 21 passes. The second housing portion 22m has a storage space S for accommodating the portion of the power supply side wall 22e of the spring 23 and the foil 24. The first housing portion 22k and the second housing portion 22m are mounted to the main frame 11 of the filament unit 2 with an insulator between them. That is, the first housing portion 22k and the second housing portion 22m are electrically insulated from each other.

[0124] As described above, the electron beam irradiation device 1, even when including the tension holding unit 20F, can achieve the same effect as when including the tension holding unit 20 in the embodiment. Furthermore, the tension holding unit 20F does not directly supply power to the movable body 21 from the inner periphery of the guide hole 22d provided in the first housing portion 22k, but can supply power to the movable body 21 from the power supply sidewall portion 22e via the foil 24. Thus, since the tension holding unit 20F is not a structure that supplies power between mutually sliding components, it can reliably supply power to the movable body 21.

[0125] (Seventh variation)

[0126] like Figure 14 As shown, the tension holding unit 20G in the seventh modification is formed by dividing the housing 22A of the tension holding unit 20A in the first modification into two parts. Specifically, the tension holding unit 20G includes a movable body 21A, a housing 22G, a spring 23, and an annular elastic body 25. The housing 22G includes a first housing portion 22n and a second housing portion 22p.

[0127] A guide hole 22d is provided on the first housing portion 22n for the movable body 21A to pass through. One end of the spring 23 is connected to the right end of the movable body 21A. The other end of the spring 23 is connected to the second housing portion 22p. The first housing portion 22n and the second housing portion 22p are mounted on the main frame 11 of the filament unit 2 with an insulator between them. That is, the first housing portion 22n and the second housing portion 22p are electrically insulated from each other.

[0128] The end of the power supply line 14 is connected to the first housing portion 22n. In the tension holding unit 20G, power is supplied to the filament 10 from the first housing portion 22n via the annular elastic body 25 and the movable body 21A. This suppresses the heating of the spring 23 caused by energization and suppresses fluctuations in the tension of the spring 23 due to heat. In this way, the tension holding unit 20G can supply power to the filament 10 via the annular elastic body 25 and the movable body 21A while maintaining the tension of the filament 10 by the spring 23.

[0129] (An example of a method for fixing a filament)

[0130] Next, an example of a method of fixing the filament 10 to the front end portion of the movable body 21 of the tension holding unit 20 in the embodiment will be described. The fixing method of the filament 10 described below can also be applied to the various modified examples of the tension holding unit described above. As shown in FIG. 1, a bolt hole 21f extending along the axis L is provided in the front end surface (the other end surface) of the cylindrical portion 21a of the movable body 21. A filament fixing member 40 is attached to the front end portion (the one end side portion) of the filament 10. The filament fixing member 40 includes a cylindrical portion 41 and a flange portion 42. The front end portion of the filament 10 is fixed by passing through the cylindrical portion 41. Here, the cylindrical portion 41 can also sandwich the front end portion of the filament 10 in the inner peripheral surface by riveting and be attached to the filament 10. The flange portion 42 protrudes outward from the outer peripheral surface of the end portion of the cylindrical portion 41 on the movable body 21 side. Figure 15

[0131] The filament fixing member 40 is fixed to the front end portion of the movable body 21 by a through-bolt 50. The through-bolt 50 is provided with a through-hole 50a extending along the axial direction of the through-bolt 50. The cylindrical portion 41 of the filament fixing member 40 and a portion of the filament 10 pass through the through-hole 50a in a manner in which the flange portion 42 abuts against the front end portion of the through-bolt 50. The through-bolt 50 is attached to the bolt hole 21f of the cylindrical portion 21a in a state in which the cylindrical portion 41 and the like pass through the through-hole 50a. The filament fixing member 40 attached to the front end portion of the filament 10 is fixed to the front end portion of the cylindrical portion 21a by sandwiching the flange portion 42 with the front end portion of the through-bolt 50 and the bottom portion of the bolt hole 21f of the cylindrical portion 21a.

[0132] In this way, in the structure shown in FIG. 1, the filament 10 can be easily attached to and detached from the movable body 21 by using the through-bolt 50. Thus, in this structure, the replacement of the filament 10 becomes easy. In addition, according to this structure, the movable body 21 can suppress the axis deviation and easily pull the filament 10 in the direction of the axis L. Figure 15

[0133] The above describes the embodiment and the various modified examples of the present application, but the present application is not limited to the above-described embodiment and the various modified examples. Furthermore, the structures described below can be applied to all of the embodiment and the various modified examples as much as possible. In the tension holding unit 20 of the embodiment, the spring 23 can also not be a structure that stretches the movable body 21 in the direction along the axis L as long as it is provided with a structure that guides the moving direction of the movable body 21, such as by the guide hole 22d. For example, even if the spring 23 is a structure that stretches the movable body 21 in a direction slightly deviated from the axis L, it can guide the moving direction of the movable body 21 in the direction of the axis L by the guide hole 22d. In the tension holding unit 20 of the embodiment, the movable body 21 is not limited to a structure in which the center of gravity of the movable body 21 is located on the axis L.

[0134] ​​In the tension holding unit 20 in the embodiment, it is not limited to the case where the spring 23 is housed in the housing space S of the housing 22. For example, in the case where the housing 22 does not have the housing space S, the spring 23 can also be a structure that is not housed in the housing space S. In the tension holding unit 20 of the embodiment, the spring 23 is not limited to a structure that is arranged in such a manner that it cannot be directly seen from the filament 10. In the tension holding unit 20 of the embodiment, the movable body 21 can also not be guided by the guide hole 22d of the housing 22. Further, in the case where the movable body 21 is guided by the guide hole 22d of the housing 22, the shapes of the movable body 21 and the guide hole 22d are not limited to a cylindrical shape that extends along the axis line L. The movable body 21 and the guide hole 22d can also have a shape other than a cylindrical shape, such as a polygonal shape.

[0135] The filament 10 is not limited to a member in which all portions are linear. For example, the filament 10 can also have a coil-shaped portion that is in a coil shape. In this case, the filament 10 is also capable of holding the tension of the filament 10 by the coil-shaped portion that it has. In this way, the electron beam irradiation apparatus is capable of causing the filament 10 to have a function of holding tension.

[0136] In addition, the filament unit 2 can also be used as an electron beam generation source provided to an X-ray irradiation apparatus that irradiates X-rays. In the case where the filament unit 2 is used as an electron beam generation source of an X-ray irradiation apparatus, a main body portion that houses the filament unit 2, an X-ray target (for example, tungsten, molybdenum, or the like) that generates X-rays by the incidence of electrons from the filament unit 2 as an X-ray generation portion, and an X-ray extraction portion for extracting X-rays to the outside of the main body portion are included. In this case, as an example of the X-ray extraction portion, Figure 1 The window portion 9 illustrated can also be changed to a window portion for X-ray irradiation that is composed of a window material (for example, beryllium, diamond, or the like) that has high transparency to X-rays and an X-ray target provided to the face of the window material on the vacuum space R side. Thereby, it is possible to cause the electron beam EB that is emitted from the filament unit 2 to be incident to the X-ray target and to cause X-rays to be emitted from the X-ray target.

[0137] At least a part of the above-described embodiment and various modifications can also be combined arbitrarily.

[0138] Explanation of Reference Numerals

[0139] 1 … Electron beam irradiation apparatus

[0140] 2 … Filament unit (electron beam generation source)

[0141] 10 … Filament (electron emission portion)

[0142] 11 … Main frame (frame portion)

[0143] 20, 20A to 20G … Tension holding unit

[0144] 21, 21A-21C... movable body

[0145] 22, 22A, 22B, 22F, 22G... housing (support portion, housing portion)

[0146] 22d... guide hole (movable portion holding portion)

[0147] 23, 26... spring (tension holding portion)

[0148] L... axis

[0149] S... storage space (internal space)

Claims

1. An electron beam generating source comprising: an electron emitting portion extending in a desired axis and emitting electrons; a movable portion connected to one end of the electron emitting portion; a support portion supporting the movable portion in such a manner that the movable portion is movable along the axis; and a tension maintaining portion maintaining tension of the electron emitting portion by applying a pressing force or a stretching force to the movable portion, the movable portion and the tension maintaining portion are respectively arranged on the axis, the support portion includes a housing portion including an internal space in which the tension maintaining portion is housed, the housing portion includes a movable portion holding portion extending along the axis and holding the movable portion in such a manner that the movable portion is movable along the axis, the movable portion holding portion is a through-hole in a cylindrical shape extending along the axis.

2. The electron beam generating source according to claim 1, wherein the tension maintaining portion applies the pressing force or the stretching force to the movable portion to move the movable portion along the axis.

3. The electron beam generating source according to claim 1, wherein the movable portion is arranged such that a center of gravity of the movable portion is located on the axis.

4. The electron beam generating source according to claim 2, wherein the movable portion is arranged such that a center of gravity of the movable portion is located on the axis.

5. The electron beam generating source according to claim 1, wherein the electron emitting portion and the tension maintaining portion are constituted by different members from each other.

6. The electron beam generating source according to claim 2, wherein the electron emitting portion and the tension maintaining portion are constituted by different members from each other.

7. The electron beam generating source according to claim 3, wherein the electron emitting portion and the tension maintaining portion are constituted by different members from each other.

8. The electron beam generating source according to claim 4, wherein the electron emitting portion and the tension maintaining portion are constituted by different members from each other.

9. The electron beam generating source according to any one of claims 1 to 8, wherein the housing portion covers the tension maintaining portion such that the tension maintaining portion is not directly seen from the electron emitting portion.

10. The electron beam generating source according to any one of claims 1 to 8, wherein the electron emitting portion is in a straight line shape.

11. The electron beam generating source according to claim 9, wherein the electron emitting portion is in a straight line shape.

12. The electron beam generating source according to any one of claims 1 to 8, wherein the electron emitting portion has a coil-like portion in a coil shape.

13. The electron beam generating source according to claim 9, wherein the electron emitting portion has a coil-like portion in a coil shape.

14. The electron beam generating source according to any one of claims 1 to 8, further comprising a frame portion supporting the other end of the electron emitting portion and the tension maintaining portion, respectively.

15. The electron beam generating source according to claim 9, further comprising a frame portion supporting the other end of the electron emitting portion and the tension maintaining portion, respectively.

16. The electron beam generating source according to claim 10, wherein ​ ​ Further comprising a frame portion supporting the other end portion of the electron emission portion and the tension holding portion, respectively.

17. The electron beam generating source according to claim 11, wherein Further comprising a frame portion supporting the other end portion of the electron emission portion and the tension holding portion, respectively.

18. The electron beam generating source according to claim 12, wherein Further comprising a frame portion supporting the other end portion of the electron emission portion and the tension holding portion, respectively.

19. The electron beam generating source according to claim 13, wherein Further comprising a frame portion supporting the other end portion of the electron emission portion and the tension holding portion, respectively.

20. An electron beam irradiation apparatus comprising: the electron beam generating source according to any one of claims 1 to 19; a main body portion accommodating the electron beam generating source; and an electron extraction portion for extracting electrons from the electron beam generating source to the outside of the main body portion.

21. An X-ray irradiation apparatus comprising: the electron beam generating source according to any one of claims 1 to 19; a main body portion accommodating the electron beam generating source; an X-ray generating portion generating X-rays by incident of electrons from the electron beam generating source; and an X-ray extraction portion for extracting the X-rays to the outside of the main body portion.

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