JP4384520B2 - Accelerating tube - Google Patents

Description

  The present invention relates to a structure of an acceleration tube for accelerating an elementary particle beam, and more specifically, a structure of a fixed portion of an acceleration tube used for an electron acceleration tube or a particle acceleration device used for an electron microscope or the like. About.

  A conventional accelerator tube is shown in FIG. In FIG. 3, 11 is an annular insulating member, 12 is an annular electrode, 13 is an acceleration tube body, and 15 is a flange. The acceleration tube body 13 and the flange 15 are joined together to form an acceleration tube.

The acceleration tube main body 13 includes a plurality of annular electrodes 12 made of a metal such as iron (Fe) -nickel (Ni) -cobalt (Co) alloy and an annular insulating member made of an electrical insulating material such as alumina (Al ₂ O ₃ ) ceramics. 11 is manufactured by joining a plurality of annular electrodes 12 and a plurality of annular insulating members 11 through a brazing material such as silver (Ag) brazing so as to be sandwiched alternately and coaxially, and has a cylindrical shape as a whole. It has become.

  Of the annular electrode 12, the annular electrode 12 positioned at both ends of the acceleration tube main body 13 is formed with a cylindrical standing wall portion 14, and the end surface of the standing wall portion 14 is made of a metal such as stainless steel (SUS). The flange 15 is welded and fixed.

  The flange 15 is provided with a plurality of mounting bolt holes on the outer periphery, and the accelerating tube main body 13 is mounted inside the electron microscope or the like by bolting the mounting bolt holes of the flange 15 to a mounting member provided in the electron microscope or the like. Placed in.

A reinforcing annular insulating member 16 made of an electrically insulating material such as Al ₂ O ₃ ceramic brazed to both ends of the acceleration tube main body 13 and the flange 15 is brazed to the annular electrode 12. Is provided to form an acceleration tube.

With such a configuration, even when an external force such as vibration is applied to the annular electrode 12, the elastic deformation of the annular electrode 12 is suppressed, and the resonance vibration of the acceleration tube main body 13 is also caused by the elastic deformation of the annular electrode 12. Effectively blocked, the electric field inside the accelerating tube main body 13 was stabilized, the acceleration of the electron flow was made constant, and it was possible to make it accurate and stable.
JP-A-8-222160

However, in the conventional acceleration tube, when the flange 15 is welded to the end face of the standing wall portion 14 of the annular electrode 12, the annular electrode 12 and the flange 15 made of metal and an electrically insulating material such as Al ₂ O ₃ ceramics are used. Heat is applied to the reinforcing annular insulating member 16, and a difference in thermal expansion occurs between the reinforcing annular insulating member 16 and the annular electrode 12 and the flange 15. In some cases, the stress due to the difference in thermal expansion acts on the reinforcing annular insulating member 16, and the reinforcing annular insulating member 16 is damaged such as cracks. As a result, it becomes impossible to reinforce the joint between the acceleration tube main body 13 and the flange 15 via the reinforcing annular insulating member 11, the standing wall portion 14 is elastically deformed, and the acceleration tube main body 13 vibrates. The electron flow also oscillates in the same manner as the acceleration tube main body 13, and it is difficult to control the electron flow. In addition, the electron flow in the accelerating tube main body 13 is disturbed and the electron flow cannot be accelerated.

  In addition, since the conventional acceleration tube has a structure in which the flange 15 is welded to the end surface of the standing wall portion 14, when the acceleration tube body 13 is enlarged, the standing wall portion 14 cannot support the acceleration tube body 13 completely. Thus, it becomes difficult to join the acceleration tube main body 13 to the flange 15 firmly and airtightly at the standing wall portion 14. When the accelerating tube body 13 cannot be firmly joined to the flange 15 by the standing wall portion 14, the standing wall portion 14 is elastically deformed and the accelerating tube body 13 vibrates, and the electron flow in the accelerating tube body 13 also vibrates the accelerating tube body 13. It may be difficult to control the electron flow. And there was a problem that the electron flow is disturbed and the electron flow cannot be accelerated. If the accelerating tube main body 13 cannot be airtightly joined to the flange 15 by the standing wall portion 14, the atmosphere in the internal space of the accelerating tube main body 13 cannot be made constant, and the electron flow is disturbed and the electron flow is disturbed. The problem was that acceleration could not be achieved.

  Therefore, the present invention has been completed in view of the above-described conventional problems, and an object of the present invention is to provide an acceleration tube that can be reliably and stably accelerated to a predetermined speed without causing disturbance in the electron flow. Is to provide.

  An acceleration tube of the present invention includes an acceleration tube main body configured such that a plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined and the annular insulating members are positioned at both ends, and the acceleration tube An annular metal member coaxially attached to both end faces of the main body, and an annular flange coaxially welded to the outer main surface of the annular metal member, the annular metal member having an inner circumference The cylindrical portion protrudes outward in the axial direction and the outer peripheral side is a flange portion, and the flange has a protrusion portion that contacts the outer main surface of the flange portion of the annular metal member on the outer peripheral portion. And the tip of the cylindrical portion of the annular metal member is fitted and welded to the opening of the flange, and the outer main surface of the flange portion of the annular metal member is the protruding portion of the flange. Specially welded to To.

  Preferably, in the acceleration tube according to the present invention, the annular metal member has a plurality of cutout portions formed at the same interval on an outer peripheral portion, and a portion along the cutout portion of the outer main surface of the flange portion. It is not welded to the protrusion of the flange.

  Preferably, the acceleration tube according to the present invention is a reinforcing annular member joined to the annular metal member and the flange between the flange portion of the annular metal member and a portion inside the projecting portion of the flange. An insulating member is provided.

  An acceleration tube according to the present invention includes an acceleration tube main body configured such that a plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined and annular insulating members are positioned at both ends, and the acceleration tube main body An annular metal member that is coaxially attached to both end surfaces of the annular metal member, and an annular flange that is coaxially welded to the outer main surface of the annular metal member. The outer peripheral side is a flange part, and the flange is formed with a protrusion part that contacts the outer main surface of the flange part of the annular metal member over the entire periphery. The annular metal member has a cylindrical portion with a front end fitted into the opening of the flange and welded, and an outer main surface of the flange portion of the annular metal member is welded to the projecting portion of the flange. The flange is welded at two locations Since the annular metal member is welded at the flange opening and outer periphery, the connection between the annular metal member and the flange is strong against external forces applied in either the axial direction or the circumferential direction of the acceleration tube body. It can be held. And even if an acceleration tube enlarges, it becomes possible to hold | maintain an acceleration tube main body firmly, and can prevent effectively that an acceleration tube main body vibrates.

  Further, the acceleration tube main body can be airtightly joined to the flange, and the atmosphere in the internal space of the acceleration tube main body can be always kept constant.

  As a result, it is possible to prevent the electron flow in the accelerating tube main body from being disturbed, and the electron flow can be reliably and stably accelerated to a predetermined speed.

  Preferably, in the acceleration tube of the present invention, the annular metal member has a plurality of cutout portions formed at the same interval on the outer peripheral portion, and a portion along the cutout portion of the outer main surface of the flange portion is a protruding portion of the flange Since the outer peripheral portion of the annular metal member and the protruding portion of the flange are welded at a distance from each other, the heat of welding is suppressed when welding the flange portion of the annular metal member and the protruding portion of the flange. It is possible to reduce stress due to a difference in thermal expansion from the annular metal member applied to the annular insulating member. And it becomes possible to reliably prevent breakage such as cracks in the annular insulating member. Therefore, the airtight reliability of the internal space of the acceleration tube body can be further improved.

  Preferably, in the acceleration tube according to the present invention, a reinforcing annular insulating member joined to the annular metal member and the flange is provided between the flange portion of the annular metal member and a portion inside the protruding portion of the flange. As a result, the acceleration tube main body is more firmly fixed to the flange, and the annular metal member can be reliably prevented from being elastically deformed, and the acceleration tube main body can be reliably prevented from vibrating. Then, it is possible to reliably prevent disturbance of the electron flow in the accelerating tube main body, and to accelerate the electron flow more reliably and more stably at a predetermined speed.

  The acceleration tube of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an example of an embodiment of an acceleration tube according to the present invention. In this figure, 1 is an annular insulating member, 2 is an annular electrode, 3 is an accelerating tube main body, 4 is an annular metal member, and 5 is a flange.

  The acceleration tube of the present invention includes an acceleration tube main body 3 configured such that a plurality of annular electrodes 2 and a plurality of annular insulating members 1 are alternately and coaxially joined and the annular insulating members 1 are positioned at both ends, An annular metal member 4 made of an annular metal coaxially attached to both end faces of the acceleration tube main body 3 and an annular flange 5 welded coaxially to the outer main surface of the annular metal member 4 are provided. The annular metal member 4 has a cylindrical portion 4a that protrudes outward in the axial direction of the accelerating tube body 3 on the inner peripheral side and a flange 4b on the outer peripheral side, and the flange 5 has an annular metal member 4 on the outer peripheral portion. A projecting portion 5a that contacts the outer main surface of the flange portion 4b is formed over the entire circumference, and the tip of the cylindrical portion 4a of the annular metal member 4 is fitted into the opening 5b of the flange 5 and welded. The outer main surface of the flange 4b of the metal member 4 is the flange 5 It is welded to the projecting portion 5a.

The annular insulating member 1 in the present invention is an annular member made of an electrical insulating material such as alumina (Al ₂ O ₃ ) ceramics, such as an annular shape, an elliptical annular shape, and an oval annular shape. The annular insulating member 1 has a function of electrically insulating the annular electrodes 2 located at both ends thereof. The annular insulating member 1 has, for example, a metallized layer such as molybdenum (Mo), manganese (Mn), tungsten (W) or the like previously applied to both end faces thereof, and a metal layer made of a metal such as Ni is covered thereon. It is worn. The annular electrode 2 is joined to the metal layer via a brazing material such as silver (Ag) brazing or Ag-copper (Cu) brazing.

When the annular insulating member 1 is made of, for example, Al ₂ O ₃ ceramics, a raw material powder such as Al ₂ O ₃ , silica (SiO ₂ ), calcia (CaO), magnesia (MgO) is filled in a mold having a predetermined shape. At the same time, it is pressed at a constant pressure to form a cylindrical green molded body, and then the raw molded body is fired at a high temperature of about 1600 ° C.

  In the case where the metallized layers are applied to both end faces of the annular insulating member 1, after the molded body is fired, a conductive paste obtained by mixing an appropriate binder and solvent with metal powder such as W, Mo, Mn, etc. is used as the annular insulating member 1. A metallized layer is formed by printing on both end faces of the film by screen printing or the like and baking at a temperature of about 1500 ° C. Preferably, a metal layer made of a metal such as Ni is applied to the metallized layer by an electrolytic plating method or an electroless plating method. This structure prevents the metallized layer from being deteriorated due to oxidation or corrosion. Can be prevented.

  The annular electrode 2 functions to form an electric field for accelerating the electron flow in the internal space of the accelerating tube body 3 by applying a high voltage between them, and iron (Fe) -nickel (Ni). -Made of a metal material such as cobalt (Co) alloy or titanium (Ti).

  The annular electrode 2 is formed by, for example, a predetermined annular shape, an elliptical annular shape, or an oval annular shape of an ingot such as an Fe—Ni—Co alloy by a conventionally known metal working method such as a rolling method or a punching method. It is manufactured by processing into an annular shape.

  The annular insulating member 1 and the annular electrode 2 are arranged coaxially so that their central axes substantially coincide with each other, and a brazing material such as Ag brazing or Ag-Cu brazing is sandwiched between them. At the same time, the annular insulating member 1 and the annular electrode 2 are brazed and joined by heating and melting the brazing material, thereby producing the acceleration tube main body 3. The central axes of the annular insulating member 1 and the annular electrode 2 may be coincident within a range that does not substantially disturb the electron flow, specifically within a range of about 0.05 to 1 mm.

  The annular metal member 4 functions as an attachment member for attaching the acceleration tube main body 3 to the flange 5 and is made of a metal material such as Fe—Ni—Co alloy or Ti.

  The annular metal member 4 is formed of, for example, an ingot such as a Fe—Ni—Co alloy by a predetermined circular, elliptical, or oval shape by a conventionally known metal processing method such as a rolling method, a drawing method, or a punching method. It is processed into the shape which becomes the cylindrical part 4a in which the inner peripheral side protrudes in the axial direction.

  The annular metal member 4 is made of a brazing material such as Ag brazing or Ag-Cu brazing on the annular insulating member 1 configured such that opposite main surfaces from which the cylindrical portion 4a protrudes are located at both ends of the accelerating tube main body 3. And the cylindrical portion 4a is joined to both ends of the acceleration tube main body 3 in a state of protruding outward in the axial direction of the acceleration tube main body 3.

  The flange 5 is a ring-shaped member having a circular or oval shape in plan view and a circular, elliptical, or oval through hole provided in the center, and serves as a mounting member for an electronic device such as an electron microscope. And made of a metal material such as SUS.

  And the front-end | tip of the cylindrical part 4a of the cyclic | annular metal member 4 is engage | inserted in the opening 5b of the flange 5, and the front-end | tip of the cylindrical part 4a and the end surface of the opening 5b of the flange 5 are welded by welding methods, such as a TIG welding method and an electron beam welding method. At the same time, the outer main surface of the flange portion 4b on the outer peripheral side of the annular metal member 4 is brought into contact with the protruding portion 5a of the flange 5 so that the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 Welding is performed by a welding method such as an electron beam welding method to produce an acceleration tube as a product in which flanges 5 are attached to both ends of the acceleration tube main body 3.

  For example, a plurality of mounting bolt holes are provided in the vicinity of the outer peripheral portion of the flange 5, and the accelerating tube main body 3 is electronically connected by bolting the mounting bolt holes to a mounting member provided in an electron microscope or the like. It is mounted in an electronic device such as a microscope.

  Thus, the acceleration tube body 3 is mounted in an electronic device such as an electron microscope, and a high voltage of about 10 kV to 50 kV is applied between the annular electrodes 2 to form a predetermined electric field inside the acceleration tube body 3 and this acceleration. If an electron flow is passed through the internal space of the tube body 3, the electron flow is accelerated to a predetermined speed in a predetermined direction by an electric field, thereby functioning as an acceleration tube.

  According to the accelerating tube of the present invention, the annular metal member 4 and the flange 5 are the cylindrical portion 4 a of the annular metal member 4, the opening 5 b of the flange 5, and the flange 4 b of the annular metal member 4 and the protruding portion 5 a of the flange 5. Since it becomes a structure welded at a location, the joint area between the annular metal member 4 and the flange 5 can be enlarged, and the annular metal member 4 is welded at the opening and the outer peripheral portion of the flange 5. The joint between the annular metal member 4 and the flange 5 can be firmly held against an external force applied in either the axial direction or the circumferential direction. And even if an acceleration tube enlarges, it becomes possible to hold | maintain the acceleration tube main body 3 firmly, and can prevent effectively that the acceleration tube main body 3 vibrates.

  Further, since the accelerating tube main body 3 is hermetically joined to the annular metal member 4 via a brazing material such as Ag brazing or Ag—Cu brazing, and the annular metal member 4 is hermetically welded to the flange 5, the accelerating tube The main body 3 can be airtightly joined to the flange 5, and the atmosphere in the internal space of the accelerating tube main body 3 can always be a constant atmosphere.

  As a result, it is possible to prevent the electron flow in the accelerating tube main body 3 from being disturbed by the vibration of the accelerating tube main body 3, and the electron flow can be reliably and stably accelerated to a predetermined speed.

  Preferably, in the accelerating tube having the above-described configuration, as shown in FIG. 2, the annular metal member 4 has a plurality of cutout portions 4c formed at substantially the same interval on the outer peripheral portion, and a cutout in the outer main surface of the flange portion 4b. It is preferable that a portion along the portion 4 c is not welded to the protruding portion 5 a of the flange 5.

  With this configuration, the outer main surface of the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 are welded with a gap therebetween, and the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 are connected to TIG. When welding is performed by a welding method such as a welding method or an electron beam welding method, heat of welding can be suppressed, and stress due to a difference in thermal expansion from the annular metal member 4 applied to the annular insulating member 1 can be reduced. And it becomes possible to reliably prevent the annular insulating member 1 from being damaged such as cracks. Therefore, the airtight reliability of the internal space of the acceleration tube body 3 can be further improved.

  A plurality of notches 4 c are formed at substantially the same interval on the outer periphery of the annular metal member 4. The shape of the notch 4c may be various shapes such as an arc, a parabola, or a polygon. Preferably, the shape has a curved shape, and even if the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 are welded at a distance, stress concentration occurs around the notch portion 4c. It is possible to prevent the annular metal member 4 from being deformed. As a result, it is possible to prevent stress from being applied to the annular insulating member 1 due to the deformation of the annular metal member 4, to prevent the annular insulating member 1 from being damaged such as cracks, and to prevent the position of the acceleration tube body 3 from being displaced. can do.

  Preferably, 0.4 to 0.7 times the entire length of the outer periphery of the annular metal member 4 is notched by the notch 4c. When welding the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5, it is possible to effectively reduce the stress due to the difference in thermal expansion between the annular metal member 4 and the annular metal member 4. It is possible to reliably prevent the occurrence of breakage such as cracks, to secure a moderately welded portion, and to firmly bond and fix the accelerator tube body 3 to the flange 5 without elastically deforming.

  When the length notched by the notch 4c is less than 0.4 times the entire length of the outer periphery of the annular metal member 4, the length by which the flange 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 are welded is sufficient. It becomes long and a large stress is easily applied to the annular insulating member 1 at the time of welding joining, and the annular insulating member 1 is easily damaged by cracks or the like. If the length cut out by the cutout portion 4c exceeds 0.7 times the total length of the outer periphery of the annular metal member 4, the flange portion 4b of the annular metal member 4 and the protruding portion 5a of the flange 5 are welded. As a result, the length of the accelerating tube main body 3 is difficult to be firmly fixed to the flange 5, and the position of the accelerating tube main body 3 is easily displaced.

  Preferably, in the acceleration tube having the above-described configuration, as shown in FIG. 1, the annular metal member 4 and the flange 5 are disposed between the flange portion 4 b of the annular metal member 4 and a portion inside the protruding portion 5 a of the flange 5. It is preferable that the reinforcing annular insulating member 6 joined to the above is provided.

  By joining the reinforcing annular insulating member 6 to both the annular metal member 4 and the flange 5 positioned at both ends of the acceleration tube main body 3, the elastic deformation of the annular metal member 4 is effectively prevented.

  With this configuration, the accelerating tube main body 3 is more firmly fixed to the flange 5, the annular metal member 4 can be reliably prevented from being elastically deformed, and the accelerating tube main body 3 can be reliably prevented from vibrating. Then, it is possible to reliably prevent the electron flow in the accelerating tube main body 3 from being disturbed, and to accelerate the electron flow reliably and more stably at a predetermined speed.

  The reinforcing annular insulating member 6 may be made of a material approximating the thermal expansion coefficient of the annular insulating member 1 or a material having exactly the same thermal expansion coefficient, and also has an annular or elliptical shape similar to the annular insulating member 1. It is good to arrange | position in the position which opposes the cyclic | annular insulation member 1 via the cyclic | annular metal member 4 with cyclic | annular members, such as cyclic | annular form and an oval cyclic | annular form.

  With this configuration, stress due to a difference in thermal expansion with the flange 5 applied to the annular insulating member 1 can be greatly reduced, and when the flange 5 is attached to the accelerating tube body 3, damage such as cracks occurs in the annular insulating member 1. It can be surely prevented. That is, the inside of the accelerating tube main body 3 can be reliably kept airtight.

For example, when the annular insulating member 1 is made of Al ₂ O ₃ ceramics, the reinforcing annular insulating member 6 is also made of Al ₂ O ₃ ceramics, or has a thermal expansion coefficient of Al ₂ O ₃ ceramics such as Fe—Ni—Co alloy. It should be made of a similar material.

When the reinforcing annular insulating member 6 is made of, for example, Al ₂ O ₃ ceramics, metallized layers such as Mo, Mn, and W are previously applied to both end surfaces thereof, and a metal layer made of a metal such as Ni is deposited thereon. Then, it is joined to the annular metal member 4 and the flange 5 via a brazing material such as Ag brazing or Ag-Cu brazing.

When the reinforcing annular insulating member 6 is made of, for example, Al ₂ O ₃ ceramics, the reinforcing annular insulating member 6 may be produced in the same manner as in the production method of the annular insulating member 1 described above.

  Further, when the reinforcing annular insulating member 6 is made of a metal such as Fe-Ni-Co alloy, for example, an ingot such as Fe-Ni-Co alloy is predetermined by a conventionally known metal processing method such as a rolling method or a punching method. It is manufactured by processing into an annular shape, an elliptical annular shape, an oval annular shape, or the like.

  In addition, this invention is not limited to the example of the above embodiment, If it is in the range which does not deviate from the summary of this invention, it will not interfere at all. For example, the annular electrode 2 may be made of a material having a low electrical resistance such as copper (Cu), and heat is not generated even when a high voltage is applied to the annular electrode 2. It can be effectively prevented.

It is sectional drawing which shows an example of embodiment of the acceleration tube of this invention. It is a top view which shows the other example of embodiment of the cyclic | annular metal member of the acceleration tube of this invention. It is sectional drawing which shows the example of the conventional acceleration tube.

Explanation of symbols

1: annular insulating member 2: annular electrode 3: acceleration tube main body 4: annular metal member 4a: protruding portion 4b: flange portion 4c: notch portion 5: flange 5a: protruding portion 5b: opening 6: annular insulating member for reinforcement

Claims (3)

A plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined, and the annular insulating member is disposed at both ends, and coaxially disposed at both end surfaces of the accelerating tube main body And an annular flange that is coaxially welded to the outer main surface of the annular metal member, and the inner circumferential side of the annular metal member protrudes outward in the axial direction. The flange is formed as a cylindrical portion and the outer peripheral side is a flange portion, and the flange has a projecting portion that is in contact with the outer main surface of the flange portion of the annular metal member on the outer periphery, The front end of the cylindrical portion of the annular metal member is fitted into the opening of the flange and welded, and the outer main surface of the flange portion of the annular metal member is welded to the protruding portion of the flange. Characteristic acceleration tube. In the annular metal member, a plurality of cutout portions are formed at the same interval on the outer peripheral portion, and a portion along the cutout portion of the outer main surface of the flange portion is welded to the protruding portion of the flange. The acceleration tube according to claim 1, which is not provided. A reinforcing annular insulating member joined to the annular metal member and the flange is provided between the flange portion of the annular metal member and a portion inside the projecting portion of the flange. The acceleration tube according to claim 1 or 2.

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