JP2007087846A - Accelerating tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an accelerating tube capable of stably accelerating charged particles to a prescribed speed while having good coaxiality, and generating no disturbance in the beam of the charged particles such as elementary particles and ions. <P>SOLUTION: In this accelerating tube, a plurality of ring insulating members 1 and a plurality of ring electrodes 2 are coaxially and alternately united, a through hole 12a passing through both main surfaces is provided in the ring electrode 2, a recessed part 1a is provided on the end surface of the ring insulating member 1 abutting on the through hole 2a, a stopper member 7 is inserted through the through hole 2a and fitted in the recessed part 1a, and the end surface of the ring insulating member 11 and the main surface of the ring electrode 2 are united. The accelerating tube can be assembled without using a fixture or the like when uniting them, and coaxiality can be also enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of an acceleration tube for accelerating charged particles such as an elementary particle beam and an electron stream, and more particularly to a structure of a joint portion between an annular insulating member and an annular electrode constituting the acceleration tube.

  FIG. 3 is a perspective view of a conventional acceleration tube, and FIG. 4 is a sectional view thereof. In FIGS. 3 and 4, 11 is an annular insulating member, 12 is an annular electrode, 13 is a plurality of annular insulating members 11 and a plurality of annular electrodes 12 that are coaxially joined alternately and annular insulating members 11 are formed at both ends. An accelerating tube configured to be positioned.

  A flange 15 is joined to both end faces of the acceleration tube 13, and the acceleration tube is attached to an external device via the flange 15 by bolting or the like.

The acceleration tube 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.

  When joining the plurality of annular electrodes 12 and the plurality of annular insulating members 11 so as to be alternately sandwiched between them, as shown in FIG. 5, the inner peripheral surface of the annular electrode 12 and the inner peripheral surface of the annular insulating member 11 Are put into a brazing furnace while being supported by a jig made of Garbon.

  Of the annular electrode 12, an annular standing wall portion 14 is provided at both ends of the acceleration tube 13, and a flange 15 made of a metal such as stainless steel (SUS) is welded to the end surface of the standing wall portion 14 to be fixed. Is done.

  The flange 15 is provided with a plurality of mounting bolt holes on the outer peripheral portion, and the accelerating tube 13 is externally attached to the outside of 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. Attached to the device.

A reinforcing annular insulating member 16 made of an electrically insulating material such as Al ₂ O ₃ ceramic brazed to the flange 15 is brazed between the both ends of the acceleration tube 13 and the flange 15. It is arranged.
JP-A-8-222160

  However, in the conventional acceleration tube 13, the jig for supporting the inner peripheral surface of the annular insulating member 11 and the inner peripheral surface of the annular electrode 12, the processing dimension tolerance of the annular insulating member 11 and the annular electrode 12, and the annular insulation Due to factors such as the difference in thermal expansion during brazing of the member 11, the annular electrode 12, and the jig, it has been difficult to braze and join the annular insulating member 11 and the annular electrode 12 with a desired assembly accuracy. For this reason, the accuracy of the coaxiality between the annular insulating member 11 and the annular electrode 12 after brazing joining may be lowered. As a result, when passing an elementary particle beam, an electron stream, etc. through the center of the accelerating tube 13, the charged beam such as elementary particles or ions is disturbed or cannot be accelerated to a predetermined speed. Has occurred.

  Further, the inner surface of the annular insulating member 11 is slid on the carbon jig and the conductive carbon powder adheres, and the insulating property between the upper and lower main surfaces of the annular insulating member 11 is impaired. There is a problem in that an electrical short circuit is likely to occur between the annular electrodes 12, and a charged beam such as elementary particles or ions cannot be accelerated.

  Therefore, the present invention has been completed in view of the above-described conventional problems, and its purpose is to prevent charged particles such as elementary particles and ions from being disturbed and to bring charged particles to a predetermined speed. An object of the present invention is to provide an acceleration tube that can be stably accelerated.

  The acceleration tube of the present invention is an acceleration tube in which a plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined, and the annular electrode is provided with a through-hole penetrating between both main surfaces. In addition, a recess is provided in the end surface of the annular insulating member that abuts the through hole, and a stop member is inserted through the through hole and fitted into the recess, and the end surface of the annular insulating member and the annular The main surface of the electrode is bonded.

  In the acceleration tube of the present invention, preferably, the through hole of the annular electrode and the recess of the annular member are provided in at least two places in the above configuration.

  Moreover, the acceleration tube of the present invention is preferably characterized in that, in the above configuration, the stop member is made of an insulating material.

  In the acceleration tube of the present invention, a plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined, and the annular electrode is provided with a through-hole penetrating between both main surfaces. Since the recess is provided in the end surface of the annular insulating member that contacts the stopper, the stopper member is inserted through the through-hole and is inserted into the recess, and the end surface of the annular insulating member and the main surface of the annular electrode are joined. Even if a jig is not used, the positional relationship between the annular insulating member and the annular electrode is constrained by the stopper member, and the positioning is performed accurately by using the stopper member in at least two places, and the annular insulating member and the annular electrode are coaxial. Accelerating tube that can be brazed and joined. As a result, there are fewer factors that disturb the assembly accuracy when the annular insulating member and the annular electrode are joined, and a highly accurate acceleration tube can be obtained. A charged beam such as elementary particles or ions is allowed to pass through the center of the acceleration tube. In this case, it is possible to provide an accelerating tube capable of accelerating charged particles to a predetermined speed without causing disturbance in the beam.

  In addition, the inner surface of the annular insulating member is not slid by a carbon jig as in the past, and conductive carbon does not adhere, and the insulation between the upper and lower main surfaces of the annular insulating member is impaired. Absent. Therefore, since it is not electrically short-circuited through the carbon to which the annular electrodes are attached, charged particles such as elementary particles and ions can be accelerated to a predetermined speed.

  As described above, it is possible to provide an acceleration tube capable of stably accelerating charged particles at a predetermined speed without causing disturbance in a charged beam such as elementary particles or ions.

  In the accelerating tube of the present invention, preferably, the stop member is made of an insulating material. Therefore, even if the stop member is fitted into the recess of the annular insulating member and a voltage is applied to the annular electrode, the annular insulating member is There is little possibility that electric discharge breakdown will occur between the adjacent stop members. That is, since an electrical short circuit is unlikely to occur between the annular electrodes, charged particles such as elementary particles and ions can be made into a beam shape and more reliably accelerated to a predetermined speed.

  The acceleration tube of the present invention will be described in detail below. FIG. 1 is a perspective view showing an example of an embodiment of an acceleration tube according to the present invention, and FIG. 2 is a cross-sectional view partially broken longitudinally at a central portion of FIG. In these drawings, 1 is an annular insulating member, 2 is an annular electrode, and 7 is a stop member, and these are mainly the accelerating tube 3 and serve to accelerate charged particles such as elementary particles and ions. Hereinafter, a case where electrons are accelerated will be described as an example of charged particles. In the present specification, the term “up, down, left, and right” merely describes the positional relationship on the drawing, and does not mean the positional relationship during actual use.

  In the acceleration tube 3 of the present invention, a plurality of annular insulating members 1 and a plurality of annular electrodes 2 are alternately and coaxially joined, and the annular electrode 2 is attached to the annular electrode 2 at least at one place, preferably at two or more places. Is provided with a through hole 2a penetrating between the upper and lower main surfaces, and a concave portion 1a is provided at an end surface of the annular insulating member 1 contacting the through hole 2a, and the stopper member 7 is inserted through the through hole 2a. At the same time, it is inserted into the recess 1a, and the end surface of the annular insulating member 1 and the main surface of the annular electrode 2 are joined.

The annular insulating member 1 in the present invention is an annular or cylindrical member made of an electrically insulating material such as Al ₂ O ₃ ceramics, such as an annular (cylindrical), an elliptical annular, an oval annular or the like. The annular insulating member 1 has a function of electrically insulating the annular electrodes 2 located on both end faces. 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 Ag brazing or Ag-copper (Cu) brazing. The end face of the annular insulating member 1 facing the annular electrode 2 is formed with a recess 1a for fitting the stopper member 7 into at least one place, preferably two places or more.

When the annular insulating member 1 is made of, for example, Al ₂ O ₃ ceramics, raw material powders such as Al ₂ O ₃ , silica (SiO ₂ ), calcia (CaO), and magnesia (MgO) are placed in a mold having a predetermined shape. It is manufactured by filling and pressing it at a constant pressure to form a cylindrical shaped body, and then firing the shaped body 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 has a function of forming an electric field for accelerating an electron flow in the internal space of the accelerating tube 3 by applying a high voltage between them, and is made of Fe—Ni—Co alloy or titanium (Ti ) Or the like. The annular electrode 2 is provided with a through hole 2a through which the stopper member 7 is inserted so as to penetrate between the upper and lower main surfaces of the annular electrode 2 at least at one place, preferably at two or more places.

  When the recess 1a formed in the annular insulating member 1 and the through-holes 2a formed in the annular electrode 2 are provided at two or more places, the annular insulating member 1 and the annular electrode 2 are coaxially arranged so that the central axes thereof coincide with each other. It can be arranged, and can be accelerated to a predetermined speed without causing disturbance in the electron flow or the like. The concave portion 1a and the through hole 2a may be provided at any positions in the circumferential direction on the end surface of the annular insulating member 1 and the main surface of the annular electrode 2, respectively, for example, on the end surface of the annular insulating member 1 and the main surface of the annular electrode 2 You may provide the 2nd recessed part 1a and the through-hole 2a in the position away only 1/4 circumference from the recessed part 1a and the through-hole 2a provided in one place. However, it is preferable to provide at a position where the distances are as far as possible from each other, that is, a position where a straight line passing through the center point in a plan view intersects. Further, when providing more than two places, the circumference of the annular insulating member 1 and the annular electrode 2 is equally divided, for example, when provided at three places in the case of an annular shape, these are provided at positions where they form an equilateral triangle. Is preferred.

  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.

  And while stopping member 7 is inserted in each crevice 1a of annular insulating member 1, annular electrode 2 is laid through penetration hole 2a of annular electrode 2, and stopping member 7 is inserted, and further, annular insulation is carried on it. The upper annular insulating member 1 is placed so that the stopper member 7 is fitted into each recess 1 a of the member 1. Then, this is sequentially repeated to accumulate a predetermined number of stages. Note that a brazing material such as Ag brazing or Ag-Cu brazing is sandwiched between the annular insulating member 1 and the annular electrode 2. In this way, the stop member 7 is fitted into each recess 1 a of the annular insulating member 1, and the through hole 2 a of the annular electrode 2 is inserted into the stop member 7, so that the central axis of the annular insulating member 1 and the annular electrode 2 is inserted. Are arranged coaxially so that they substantially coincide. Then, the annular insulating member 1 and the annular electrode 2 are brazed and joined by heating and melting the brazing material, and the acceleration tube 3 is manufactured.

  Thus, the stop member 7 accurately positions the annular insulating member 1 and the annular electrode 2 at a predetermined position, and the annular insulating member 1 and the annular electrode 2 are accurately coaxial without using a jig. It becomes possible to braze and join together. As a result, it is possible to obtain an acceleration tube capable of accelerating electrons to a predetermined speed without causing disturbance in the electron flow when electrons are passed through the center of the acceleration tube 3.

  In addition, the inner surface of the annular insulating member 1 is not slid by a carbon jig as in the conventional case, and conductive carbon adheres and the insulation between both end surfaces of the annular insulating member 1 is impaired. There is no. Therefore, an electric current can be accelerated to a predetermined speed without being electrically short-circuited on the creeping surface of the annular insulating member 1 via the carbon to which the annular electrodes 2 are attached.

  As described above, it is possible to provide an acceleration tube capable of stably accelerating charged particles at a predetermined speed without causing disturbance in charged particles such as an electron flow.

The stop member 7 is a rod-like or plate-like member made of an electrically insulating material such as Al ₂ O ₃ ceramics or a metal material such as Fe—Ni—Co alloy or Ti, and the cross-sectional dimension thereof is It is made slightly smaller (about 0.03 mm to 0.1 mm) than the cross-sectional dimension of the recess 1a and the through hole 2a. By making it slightly smaller than the cross-sectional dimensions of the recess 1a and the through-hole 2a, it is possible to fit the stopper member 7 into the recess 1a and the through-hole 2a and to the inner surfaces of the recess 1a and the through-hole 2a. It is possible to suppress rattling of the stopper member 7 and to accurately position the annular insulating member 1 and the annular electrode 2 by the stopper member 7. Further, the annular insulating member 1 and the annular electrode 2 can be accurately arranged coaxially, and when charged particles such as an electron stream are passed through the center of the accelerating tube 3, the electron stream is disturbed. Without accelerating to a predetermined speed.

  The length of the stop member 7 is preferably shorter than the combined length of the recess 1a and the thickness of the annular electrode 2 in the through hole 2a. As a result, the stop member 7 does not fit in the recess 1a and the through hole 2a, and a gap is generated between the annular insulating member 1 and the annular electrode 2, or is stopped when the annular insulating member 1 and the annular electrode 2 are brazed and joined. Due to the thermal expansion of the member 7, it is possible to prevent the annular insulating member 1 and the annular electrode 2 from being in close contact with each other and not being firmly joined.

  The shape of the stop member 7 may be a rod shape or a plate shape having a width in the circumferential direction of the annular insulating member 1, or any other shape that can lock the annular insulating member 1 and the annular electrode 2 and is suitable for positioning. For example, it may have a spindle shape, a curved shape with protruding upper and lower end surfaces, a columnar shape or a plate shape sharpened in a polygonal pyramid shape. By making the upper and lower end surfaces into such a tapered shape, the stopper member can be easily inserted into the recess 1a or inserted through the through hole 2a, and the bottom surface of the recess 1a is a curved surface or a concave surface that comes into contact therewith. This facilitates positioning of the annular insulating member 1. In addition, since it only needs to be positioned, if there is no problem in strength, a bar shape (columnar shape) is sufficient even if it is not a plate shape.

The stop member 7 may be made of a material having the same or similar thermal expansion coefficient as the annular insulating member 1. Since the stop member 7 does not greatly expand or contract in the recess 1a at the time of brazing and joining the annular insulating member 1 and the annular electrode 2, the brazing joined portion between the annular insulating member 1 and the annular electrode 2 is caused by a difference in thermal expansion. It is possible to reduce the action of stress and to prevent the annular insulating member 1 from being damaged due to cracks or the like. For example, when the annular insulating member 1 is made of Al ₂ O ₃ ceramics, the material having the same or similar thermal expansion coefficient as the annular insulating member 1 includes Al ₂ O ₃ ceramics, Fe—Ni—Co alloy, Ti, and the like. Is mentioned.

Preferably, the stopper member 7 is made of the same material as the annular insulating member 1, for example, an insulating material such as Al ₂ O ₃ ceramics. With this configuration, the stopper member 7 is disposed in the recess 1 a of the annular insulating member 1. Even if a voltage is applied to the annular electrode 2, there is no risk of dielectric breakdown between the adjacent stop members 7 at both ends within the annular insulating member 1. That is, since an electrical short circuit is unlikely to occur between the annular electrodes 2, the electron flow or the like can be more reliably accelerated to a predetermined speed. Moreover, since it is the same material as the cyclic | annular insulating member 1, the problem by a thermal expansion difference does not arise.

  Next, in the acceleration tube of the present invention, the standing wall 4 has a function as a mounting member for mounting the acceleration tube 3 to the flange 5 and is made of a metal material such as an Fe—Ni—Co alloy or Ti. The

  The standing wall 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 formed in an annular shape such as an annular shape, and is brazed to both end surfaces of the acceleration tube 3, and flanges 5 made of metal such as SUS are welded and fixed to both end surfaces of the standing wall portion 4. The standing wall portion 4 is formed by applying a conventionally well-known metal processing method such as a drawing method or a press method at the time of production.

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

  And the flange 5 and the standing wall part 4 become an acceleration tube as a product in which the joining end surfaces of both are welded by a welding method such as a TIG welding method or an electron beam welding method, and the flange 5 is attached to both ends of the acceleration tube 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 3 is attached to an electron microscope 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.

  Thus, the accelerating tube 3 is mounted in an electronic apparatus 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 accelerating tube 3 and the accelerating tube 3. If the electron flow is allowed to pass through the internal space, the electron flow is accelerated to a predetermined speed in a predetermined direction by an electric field, thereby functioning as an electron accelerating tube.

  Further, since the acceleration tube 3 is airtightly joined to the standing wall 4 via a brazing material such as Ag brazing or Ag—Cu brazing, and the standing wall 4 is hermetically welded to the flange 5, the acceleration tube 3 is flanged. 5 and the atmosphere in the internal space of the accelerating tube 3 can always be a constant airtight atmosphere such as a vacuum. Then, the electron flow in the accelerating tube 3 can be stably accelerated to a predetermined speed without disturbing the electron flow.

In the accelerating tube having the above structure, preferably, as shown in FIG. 1, a reinforcing ring made of an electrically insulating material such as Al ₂ O ₃ ceramics brazed to the standing wall 4 and brazed to the flange 5. An insulating member 6 is provided. By joining the reinforcing annular member 6 to both the upright wall portion 4 and the flange 5 positioned at both ends of the acceleration tube 3, an elastic deformation of the upright wall portion 4 is prevented.

  With this configuration, the accelerating tube 3 is more firmly fixed to the flange 5 to reliably prevent the standing wall portion 4 from elastically deforming and to reliably prevent the accelerating tube 3 from vibrating due to elastic deformation of the standing wall portion 4. can do. Then, it is possible to prevent the electron flow in the accelerating tube 3 from being disturbed, and to stably accelerate the electron flow to a predetermined speed.

  The reinforcing annular 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 annular shape similar to the annular insulating member 1. An annular member such as an oval ring may be disposed at a position facing the annular insulating member 1 through the standing wall portion 4.

  The reinforcing annular member 6 suppresses deformation due to thermal expansion of the standing wall portion 4 and can alleviate the difference in thermal expansion of the standing wall portion 4 from the annular insulating member 1, so that the standing wall portion 4 applied to the annular insulating member 1. It is possible to reduce the stress due to the difference in thermal expansion between the annular insulating member 1 and the occurrence of breakage such as cracks in the annular insulating member 1 with certainty. That is, the inside of the accelerating tube 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 member 6 is also preferably made of Al ₂ O ₃ ceramics, or an Fe—Ni—Co alloy or the like. It is preferable to be made of a material whose thermal expansion coefficient approximates that of Al ₂ O ₃ ceramics.

When the reinforcing annular 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 faces thereof, and a metal layer made of a metal such as Ni is deposited thereon. Then, it is joined to the standing wall portion 4 and the flange 5 via a brazing material such as Ag brazing or Ag-Cu brazing.

For example, when the reinforcing annular member 6 is made of Al ₂ O ₃ ceramics, the reinforcing annular member 6 may be produced in the same manner as the annular insulating member 1 is produced.

  When the reinforcing annular member 6 is made of a metal such as an Fe—Ni—Co alloy, an ingot such as an Fe—Ni—Co alloy is formed into a predetermined circle 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, such as an annular shape, an elliptical annular shape, or an oval annular shape.

  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 Cu, and heat is not generated even when a high voltage is applied to the annular electrode 2, thereby preventing deformation of the annular electrode 2 more effectively. it can. In addition, although the case where the accelerating tube 3 and the flange 5 are joined through the upright wall portion 4 has been shown, the two may be joined directly without going through the upright wall portion 4. The accelerating tube 3 may be directly attached to an electronic apparatus such as an electron microscope without being provided.

  In the above description, the stopper member is shown as a separate member from the annular insulating member 1, but there is no problem even if it is integral with the annular insulating member 1. A protrusion to be a stop member 1 is provided integrally on the upper end surface of the member 1, and this protrusion is inserted into the through hole 2 a and is inserted into a recess 1 a provided on the lower end surface of the upper annular insulating member 1. The end surface of the annular insulating member 1 and the main surface of the annular electrode 2 may be joined.

It is a perspective view which shows an example of embodiment of the acceleration tube of this invention. It is a partial cross section perspective view which shows an example of embodiment of the acceleration tube of FIG. It is a perspective view which shows the example of the conventional acceleration tube. It is sectional drawing of the acceleration tube of FIG. It is sectional drawing which shows the example of the assembly method of the conventional acceleration tube.

Explanation of symbols

1: annular insulating member 2: annular electrode 3: acceleration tube 4: standing wall portion 5: flange 6: annular member for reinforcement 7: stop member

Claims (3)

An accelerating tube in which a plurality of annular insulating members and a plurality of annular electrodes are alternately and coaxially joined, wherein the annular electrode is provided with a through-hole penetrating between both main surfaces, and the through-hole A concave portion is provided on the end surface of the annular insulating member that contacts with the stopper, and a stopper member is inserted through the through-hole and fitted into the concave portion, so that the end surface of the annular insulating member and the main surface of the annular electrode are joined Accelerating tube characterized by being. The acceleration tube according to claim 1, wherein the through hole of the annular electrode and the concave portion of the annular member are provided in at least two places. The acceleration tube according to claim 1 or 2, wherein the stopper member is made of an insulating material.

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