JP5317062B2 - Quadrupole accelerator and method of manufacturing quadrupole accelerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quadrupole type accelerator with excellent electric performance and easy to manufacture. <P>SOLUTION: The quadrupole type accelerator is provided with a central member 11 including a central outer frame part 11a, and a first electrode 21 as well as a second electrode 22 protruded from the central outer frame part 11a, a first side member 12 including a first side outer frame part 12a, a first wall part 12b extended outward from the first side outer frame part 12a and a third electrode 23 protruded from the first wall part 12b, and a second side member 13 including a second side outer frame part 13b, a second wall part 13b extended outward from the second side outer frame part 13a and a forth electrode 24 protruded from the second wall part 13b. Each of the central member 11, the first side member 12 and the second side member 13 is integrally formed of one member, and fixed with each other by a fixing member. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a quadrupole accelerator and a method for manufacturing a quadrupole accelerator.

  High frequency accelerators for accelerating charged particles such as ions or electrons are known. The high-frequency accelerator includes an acceleration cavity for accelerating charged particles inside. The acceleration cavity forms a resonant circuit and has a unique resonant frequency. By supplying high-frequency power corresponding to the resonance frequency from the outside, a high-frequency electric field is excited inside the acceleration cavity. The high-frequency accelerator can accelerate charged particles to a desired energy by injecting charged particles at a predetermined time in a state where a high-frequency electric field is excited.

  The high frequency accelerator includes a quadrupole accelerator. The quadrupole accelerator includes four electrodes. Two pairs of the four electrodes are formed so as to face each other, and an end portion of a waveform suitable for beam acceleration is formed at the tip of each electrode in the acceleration axis direction. An electric field for accelerating and focusing the beam is formed in a space surrounded by the four electrodes, and the charged particles are accelerated by entering the charged particles into this space.

  Japanese Patent Laid-Open No. 5-62798 discloses an external resonance type quadrupole particle accelerator including an acceleration tube having therein an electrode constituting a quadrupole and a high frequency resonance circuit for supplying a resonance voltage to the electrode. ing. In this publication, it is disclosed that the high frequency resonance circuit is constituted by two coil conductors which are a capacitor and an inductance member, and the inductance member is arranged in series between the capacitor and the accelerator. According to this accelerator, it is disclosed that the resonance frequency can be changed in a wide range and the Q value can be increased.

JP-A-5-62798

  The index indicating the electrical performance of the quadrupole accelerator includes a Q value. The Q value is a value obtained by dividing the energy stored in the acceleration cavity during operation of the accelerator by the consumed energy. The larger the Q value, the longer the operation time per unit energy and the better the operation efficiency.

  In the quadrupole accelerator, when high-frequency power is supplied from the outside of the acceleration cavity, an acceleration electric field is formed inside the acceleration cavity, and a high-frequency current flows on the inner surface of the acceleration cavity. The acceleration cavity has an electrical resistance that depends on the shape, material, and the like. Electric power is consumed according to the magnitude of this electrical resistance. If the electric resistance is large, the power consumption increases and the Q value decreases. The electrical resistance also changes depending on the surface roughness of the inner surface of the acceleration cavity, and as a result, the Q value changes. The Q value increases as the surface roughness of the inner surface of the acceleration cavity decreases.

  In a conventional quadrupole accelerator manufacturing method, a plurality of constituent members are formed in advance, and an acceleration cavity is formed by joining a plurality of constituent members. In the step of forming the plurality of constituent members, a constituent member having high dimensional accuracy and a small surface roughness can be manufactured. For example, a component member with high dimensional accuracy can be manufactured by performing cutting with high accuracy. Moreover, surface roughness can be made small by performing various grinding | polishing and grinding | polishing with respect to the surface of a structural member.

  On the other hand, in the process of assembling the acceleration cavity, a plurality of components are joined by brazing or electron beam welding. As a result, depending on the construction method, the surface state of the joint portion deteriorated, and the Q value of the accelerator was reduced. In order to increase the Q value, it is necessary to perform a grinding operation or a polishing operation after the acceleration cavity is assembled.

  Further, as described above, the acceleration cavity has a specific resonance frequency. The resonance frequency depends on the shape of the acceleration cavity. The resonance frequency greatly depends on the shape so as to be affected by thermal expansion and contraction in units of microns due to temperature change of the acceleration cavity. For this reason, the resonance frequency largely depends on the manufacturing accuracy. In the manufacture of the acceleration cavity, it is preferable that each dimension is manufactured as designed.

  However, in the conventional method for manufacturing a quadrupole accelerator, there is a case where a dimensional change occurs in the process of joining the constituent members. For example, in the case where the structural members are joined together by brazing, the brazing material is disposed at the joint location after the structural members are temporarily assembled. Next, the temporarily assembled components are placed inside the high temperature furnace to melt the brazing material. At this time, the constituent members are heated as a whole, and dimensional changes due to temperature changes may occur. That is, since the temperature of the constituent members increases as a whole, thermal deformation may occur. As a result, the resonance frequency may deviate from the design value.

  As described above, in the conventional high-frequency accelerator and the manufacturing method of the high-frequency accelerator, the electrical performance tends to be deteriorated from the design value, and special work is required to improve the electrical performance. . In addition, since individual differences occur in electrical performance, it is necessary to process even one type of accelerator in consideration of individual differences.

  An object of the present invention is to provide a quadrupole accelerator excellent in electrical performance and easy to manufacture and a method for manufacturing the quadrupole accelerator.

  The quadrupole accelerator of the present invention includes a central outer frame portion, a first electrode protruding inward from the central outer frame portion, and a second electrode protruding inward from the central outer frame portion. A member, a first lateral outer frame portion, a first wall portion extending outward from the first lateral outer frame portion and having a partial shape of the acceleration cavity, and an inner side from the first wall portion A first side member disposed on one side of the central member, a second lateral outer frame portion, and an outer side from the second lateral outer frame portion. And a second wall portion having a shape of a part of the acceleration cavity, and a fourth electrode projecting inwardly from the second wall portion, and disposed on the other side of the central member A second side member. Each of the central member, the first side member, and the second side member is integrally formed from one member. The center member, the first side member, and the second side member have the center outer frame portion, the first side outer frame portion, and the second side outer frame portion fixed by a fixing member.

  In the said invention, it is preferable that the center member, the 1st side member, and the 2nd side member are mutually fixed via the electroconductive member.

  The quadrupole accelerator manufacturing method of the present invention includes a central member including a central outer frame portion, a first electrode protruding from the central outer frame portion, and a second electrode protruding from the central outer frame portion; A first lateral member including a lateral outer frame portion, a first wall portion having a partial shape of the acceleration cavity, and a third electrode projecting from the first wall portion; and a second lateral outer frame Preparing a second wall portion having a shape of a part of the acceleration cavity and a second side member including a fourth electrode protruding from the second wall portion, and on both sides of the central member An assembly step of arranging the first side member and the second side member, and fixing the central outer frame portion, the first side outer frame portion and the second side outer frame portion to each other by a fixing member; Including. The preparation step includes a step of integrally forming each of the central member, the first side member, and the second side member from one member.

  In the above invention, the preparation step includes a step of forming a reference mark on the outer surface of the central member, and a step of forming alignment marks on the outer surface of the first side member and the outer surface of the second side member. The assembly step preferably includes a step of aligning the respective members by aligning the reference mark and the alignment mark.

  In the said invention, a preparatory process has the process of forming a 1st fitting part in a center member, and the process of forming a 2nd fitting part in a 1st side member and a 2nd side member. The assembly step preferably includes a step of aligning the respective members by fitting the first fitting portion and the second fitting portion to each other.

  In the above invention, the preparation step includes a step of forming the first alignment hole in the central member and a step of forming the second alignment hole in the first side member and the second side member. The assembly step preferably includes a step of aligning the respective members by inserting alignment pins into the first alignment hole and the second alignment hole.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in electrical performance and can provide the manufacturing method of a quadrupole accelerator which is easy to manufacture, and a quadrupole accelerator.

It is the schematic of the quadrupole accelerator in embodiment. It is a schematic perspective view of the acceleration cavity of the quadrupole accelerator in an embodiment. It is the schematic perspective view which cut | disconnected the acceleration cavity of the quadrupole accelerator in embodiment. It is a schematic perspective view of the center member in an embodiment. It is a schematic perspective view of the 1st side member in embodiment.

  With reference to FIGS. 1 to 5, a quadrupole accelerator and a method of manufacturing the quadrupole accelerator in the embodiment will be described.

  FIG. 1 is a schematic diagram of a quadrupole accelerator according to the present embodiment. The quadrupole accelerator includes an acceleration cavity 1. The acceleration cavity 1 includes a cylindrical part 2 formed in a cylindrical shape. The acceleration cavity 1 protrudes inward from the cylindrical part 2 and includes electrodes 21 to 24 called vanes. Each of the electrodes 21 to 24 is electrically connected to the cylindrical portion 2.

  The quadrupole accelerator in the present embodiment includes a first electrode 21, a second electrode 22, a third electrode 23 and a fourth electrode 24. The four electrodes 21 to 24 in the present embodiment are formed integrally with a member constituting the cylindrical portion 2. Each electrode 21-24 is formed so that it may extend along the acceleration axis | shaft of a charged particle.

  The electrodes 21 to 24 in the present embodiment are formed in a triangular prism shape. Each of the electrodes 21 to 24 is formed so that the apex of the triangle having a cross-sectional shape faces the acceleration axis of the charged particle. Waveform ends are formed at the tip portions of the electrodes 21 to 24 toward the acceleration axis in order to form an electric field for accelerating and focusing charged particles in the direction of the acceleration axis. The shape of the electrode is not limited to this form, and any shape that protrudes from the cylindrical portion and whose tip is close to the acceleration axis can be adopted. For example, the electrode may be formed in a plate shape.

  The quadrupole accelerator in the present embodiment includes a power supply device for supplying high frequency power. The power supply device includes a high frequency generator 72. The high frequency generator 72 is connected to the preamplifier 73 and the main amplifier 74. The high frequency power generated by the high frequency generator 72 is amplified by the preamplifier 73 and the main amplifier 74. The high frequency power output from the main amplifier 74 is supplied to the acceleration cavity 1 via the coupler 75. As a power supply device, it is not restricted to this form, Arbitrary apparatuses which can supply high frequency electric power to the acceleration cavity 1 are employable.

  The acceleration cavity 1 has stray capacitance and stray inductance depending on the shape of the cylindrical portion 2 and the respective electrodes 21 to 24. These stray capacitance and stray inductance constitute a part of the electric circuit. An acceleration electric field is formed by supplying high-frequency power to the acceleration cavity. When an electromagnetic field of a TE210 mode or a TE211 mode suitable for a quadrupole accelerator is excited, the voltages of the first electrode 21, the second electrode 22, the third electrode 23, and the fourth electrode 24 ( The absolute value) is the same, and the electrode pair of the first electrode 21 and the second electrode 22 facing each other and the electrode pair of the third electrode 23 and the fourth electrode 24 facing each other are The polarity is reversed (plus or minus). The acceleration axis is disposed in a space between the four electrodes 21 to 24. The charged particles move while being accelerated along the acceleration axis.

  FIG. 2 shows a schematic perspective view of the acceleration cavity in the present embodiment. FIG. 3 shows a schematic perspective view when the acceleration cavity in the present embodiment is cut. FIG. 3 is a perspective view of the acceleration cavity taken along line AA in FIG. An arrow 100 is a direction in which the acceleration axis of the charged particle extends. The acceleration cavity 1 in the present embodiment is formed so as to extend in parallel with the direction of the acceleration axis.

  With reference to FIGS. 1 to 3, acceleration cavity 1 in the present embodiment includes three components. The acceleration cavity 1 includes a central member 11 including a first electrode 21 and a second electrode 22. The acceleration cavity 1 includes a first side member 12 including a third electrode 23. The acceleration cavity 1 includes a second side member 13 including a fourth electrode 24. The first side member 12 is disposed on one side of the central member 11. The second side member 13 is disposed on the other side of the central member 11. Each of the central member 11, the first side member 12, and the second side member 13 in the present embodiment is integrally formed from one member. That is, the central member and the side members are formed of a single material without having a joining line or a welding line of a plurality of parts. An additional member such as a vacuum port may be disposed in advance on the central member or the side member.

  The central member 11, the first side member 12, and the second side member 13 are fixed to each other by a fixing member. In the present embodiment, the fixing member is fixed using a bolt 51 and a nut 52.

  On the contact surface between the central member 11 and the first lateral member 12 and the contact surface between the central member 11 and the second lateral member 13, an O-ring 55 as a vacuum sealing member is disposed. The acceleration cavity 1 is hermetically sealed by disposing a vacuum sealing member between the respective constituent members.

  FIG. 4 shows a schematic perspective view of the central member in the present embodiment. The central member 11 has a central outer frame portion 11 a that constitutes a central portion of the outer frame portion of the acceleration cavity 1. The central outer frame portion 11a is formed in an annular shape when viewed in plan. The central member 11 has a first electrode 21 that protrudes inward from the central outer frame portion 11a. The central member 11 includes a second electrode 22 that protrudes inward from the central outer frame portion 11a. The first electrode 21 and the second electrode 22 are arranged so that the tip portions are directed to the acceleration axis.

  Of the outer surface of the central member 11, an entrance 61 for entering charged particles is formed on the end face in the direction of the acceleration axis. Further, an exit port 62 through which charged particles exit is formed on the end surface opposite to the end surface where the entrance port 61 is formed. The entrance 61 and the exit 62 are formed on the extension of the acceleration axis.

  A through hole 14 for passing a bolt is formed in the central outer frame portion 11a. A plurality of through holes 14 are formed along the shape of the central outer frame portion 11a. A recess 16 for placing the O-ring 55 is formed on the contact surface that contacts the first side member 12 or the second side member 13 in the surface of the central outer frame portion 11a. The recess 16 is formed in a closed shape when viewed in plan. The concave portion for arranging a vacuum sealing member such as an O-ring may be arranged in the first side member 12 and the second side member 13.

  The central member 11 in the present embodiment is formed with a reference mark 31 for determining the position of the members in the assembling process for assembling the respective members. In the present embodiment, the reference mark 31 is formed on the end surface where the entrance 61 is formed. The reference mark 31 is also formed on the end surface where the exit port 62 is formed. The reference mark 31 in the present embodiment is formed in a straight line.

  In FIG. 5, the schematic perspective view of the side member in this Embodiment is shown. The first side member 12 has a first side outer frame portion 12 a that forms a side portion of the outer frame portion of the acceleration cavity 1. The first lateral outer frame portion 12a is formed in an annular shape when viewed in plan. The 1st side member 12 has the 1st wall part 12b which has a shape of some acceleration cavities. The first wall portion 12 b constitutes the cylindrical portion 2 of the acceleration cavity 1. The first wall portion 12b is formed to extend outward from the first lateral outer frame portion 12a. The first wall portion 12b is formed in a plate shape and is coupled to the first side outer frame portion 12a. The first side member 12 includes a third electrode 23 that protrudes inward from the first wall portion 12b.

  A through-hole 15 for passing a bolt is formed in the first lateral outer frame portion 12a. The first side outer frame portion 12a is formed with an alignment mark 32 for determining an assembly position in the assembly process. In the present embodiment, alignment marks 32 are formed on both end surfaces in the direction of the acceleration axis among the end surfaces of the first lateral outer frame portion 12a.

  In FIG. 5, the first side member 12 of the two side members is described as an example, but the second side member 13 has the same configuration as the first side member 12. Have The second side member 13 includes an annular second side outer frame portion 13a. The second side member 13 includes a second wall portion 13b extending outward from the second side outer frame portion 13a and having a part of the shape of the acceleration cavity. The second side member 13 includes a fourth electrode 24 that protrudes inward from the second wall portion 13b.

  Referring to FIGS. 1 to 3, in acceleration cavity 1 in the present embodiment, central outer frame portion 11a and first side outer frame portion 12a are in close contact with each other. Further, the center outer frame portion 11a and the second side outer frame portion 13a are in close contact with each other. The central outer frame portion 11 a and the lateral outer frame portions 12 a and 13 a are fixed to each other by bolts 51 and nuts 52. The outer frame portion of the acceleration cavity 1 is formed by the central outer frame portion 11a and the lateral outer frame portions 12a and 13a.

  Next, a method for manufacturing the quadrupole accelerator in the present embodiment will be described. First, the central member 11, the first side member 12, and the second side member 13 in the present embodiment are formed. A preparatory process for preparing these components is performed. The preparation step in the present embodiment includes a step of integrally forming each of the central member 11, the first side member 12, and the second side member 13 from one member.

  In the present embodiment, the structural member is formed by mechanically cutting a solid aluminum material. In the step of forming each component member, it is preferable to perform cutting with high accuracy. In the manufacturing process, it is preferable to confirm the dimensions of the central member and the respective side members with a three-dimensional measuring instrument or the like. Further, it is preferable to reduce the surface roughness on the contact surface of the central outer frame portion and the contact surface of the lateral outer frame portion in order to ensure electrical contact. Furthermore, it is preferable to reduce the surface roughness of the inner surface of the cylindrical portion and the surface of the electrode by performing high-precision processing, polishing, or the like.

  In the preparation step, the reference mark 31 is formed on the central outer frame portion 11 a of the central member 11. Further, an alignment mark 32 is formed on the first lateral outer frame portion 12 a of the first lateral member 12. An alignment mark 32 is formed on the second lateral outer frame portion 13 a of the second lateral member 13. An O-ring 55 as a vacuum sealing member is disposed in the recess 16 formed in the central member 11.

  Next, an assembling process for fixing the central member 11, the first side member 12, and the second side member 13 to each other with bolts and nuts is performed. The first side member 12 and the second side member 13 are disposed on both sides of the central member 11. In the present embodiment, alignment is performed so that the reference mark 31 formed on the central outer frame portion 11a and the alignment marks 32 formed on the respective side outer frame portions 12a and 13a match.

  The center outer frame portion 11a, the first side outer frame portion 12a, and the second side outer frame portion 13a are fixed to each other by tightening the bolts after alignment. The central member 11, the first side member 12, and the second side member 13 are fixed to each other. When a bolt or the like is used as the fixing member, it is preferable to tighten it while performing torque management. By this method, the contact surfaces of the constituent members can be brought into contact with a uniform pressure. In this way, an acceleration cavity can be formed. An accelerator can be manufactured by connecting a power supply device, a vacuum device, or the like to the acceleration cavity.

  The reference mark and the alignment mark for alignment are not limited to a straight line, and marks having an arbitrary shape can be adopted. In addition, the reference mark and the alignment mark in the present embodiment are formed on the end surface in the direction of the acceleration axis among the outer surfaces of the acceleration cavity. Reference marks and alignment marks can be formed. For example, the reference mark and the alignment mark may be formed on the end surface in the direction perpendicular to the acceleration axis, of the outer surface of the outer frame portion of the acceleration cavity.

  Referring to FIG. 1, in the first high-frequency accelerator in the present embodiment, when an electromagnetic field of TE210 mode or TE211 mode suitable for a quadrupole accelerator is excited, the potential of each electrode at any time is increased. The signs are the same for the electrodes facing each other. The sign of the potential of the electrodes facing each other in one direction is opposite to the sign of the potential of the electrodes facing each other in the direction orthogonal to the one direction. By supplying high frequency power from the power supply device, the potential of each electrode changes with time to correspond to a sine wave. For example, at one time, when the potential of the first electrode 21 and the second electrode 22 is the maximum value (a positive value and the maximum size), the third electrode 23 and the fourth electrode The potential of the electrode 24 has a minimum value (a negative value and a maximum size). After the half period of the resonance frequency has elapsed, the electrode potential has an inverse relationship.

  The high frequency current flows on the inner surface of the cylindrical portion of the acceleration cavity 1 due to the skin effect. Therefore, current flows along the surfaces of the respective electrodes 21 to 24 and the inner surface of the cylindrical portion 2 as indicated by the arrow 104. Since there are no irregularities such as welding marks on the surfaces of the electrodes 21 to 24 and the inner surface of the cylindrical portion 2 in the present embodiment, power loss can be reduced. As a result, the Q value of the accelerator can be increased.

  In the present embodiment, the central member and the two side members are formed in advance, and these constituent members are fixed to each other by a fixing member. For this reason, in an assembly process, it can assemble by avoiding the temperature rise of a component. For example, in the assembling process, it is possible to avoid that the constituent members are heated as in the case of joining by brazing, and it is possible to suppress thermal deformation of each constituent member. The thermal deformation includes deformation due to release of internal stress when the fixing of the cylindrical portion by the fixing device is released. In the present embodiment, since the deformation of the acceleration cavity can be suppressed, the shift of the resonance frequency due to the deformation can be suppressed. The accelerator can be manufactured with high accuracy with respect to the design value.

  Thus, the quadrupole accelerator in the present embodiment is excellent in electrical performance such as a high Q value and a small shift in resonance frequency.

  Further, since the quadrupole accelerator in the present embodiment does not have a joint portion between components by welding or the like, it is not necessary to perform mechanical finishing after joining a plurality of constituent members. Can be manufactured. For example, when the respective constituent members are joined by electron beam welding, since the surface roughness is large, further grinding work and polishing work are required. The quadrupole accelerator of the present embodiment can produce an acceleration cavity having a small inner surface roughness without performing such a finishing operation.

  In addition, the quadrupole accelerator in the present embodiment can confirm the state of assembly during the assembly process. For example, by using a predetermined measuring instrument, it is possible to find a problem in the middle of the assembly process, and to correct the work. As a result, the yield can be improved. Furthermore, even after assembly, it can be easily disassembled by removing the fixing member as required. For example, the alignment can be readjusted. Alternatively, the sealing member can be easily replaced.

  In the present embodiment, the preparation step includes a step of forming the reference mark 31 on the end surface of the central member 11, the alignment mark 32 on the end surface of the first side member 12, and the end surface of the second side member 13. . The assembly process includes a process of performing alignment by aligning the reference mark 31 and the alignment mark 32. By adopting this method, the center member 11 and the side members 12 and 13 can be easily aligned.

  The alignment method in the assembly process is not limited to this form, and any method can be adopted. For example, alignment can be performed using a laser tracker. In this case, for example, of the outer surfaces of the central outer frame portion 11a and the lateral outer frame portions 12a and 13a, the outer surfaces extending in the direction parallel to the acceleration axis are formed with high accuracy. This outer surface can be used as a reference surface on which a reflector (reflector) is arranged.

  Alternatively, it is possible to perform alignment by forming in advance a fitting portion having a shape to be fitted to each other on the central member and the side member and aligning these fitting portions. In the preparation step, a first fitting portion is formed on the central member, and a second fitting portion is formed on each of the first side member and the second side member. In the assembling process, the first fitting portion and the second fitting portion are fitted to each other, whereby the respective members can be aligned. By this method, alignment can be performed easily.

  For example, in the preparation step, a convex portion as a first fitting portion is formed in the central member so that the central member and the side member can be aligned, and a concave portion as a second fitting portion is formed in the side member. Form. In the assembly process, the center member and the side member can be easily aligned by fitting the convex portion and the concave portion.

  Alternatively, alignment can be performed by previously forming an alignment hole that communicates when the center member and the side member are aligned, and inserting a pin into the alignment hole. In the preparation step, a first alignment hole is formed in the central member, and a second alignment hole is formed in the first side member and the second side member. In the assembly process, the members can be aligned with each other by inserting alignment pins into the first alignment hole and the second alignment hole. By this method, alignment can be performed easily.

  For example, in the preparation step, alignment holes are formed between through holes of bolts as fixing members with respect to the central member and the side members. The alignment hole is formed so that the alignment hole of the central member and the alignment hole of the side member communicate with each other when assembled in the acceleration cavity. The alignment holes are preferably formed at a plurality of locations. In the assembling process, the center member and the side member can be easily aligned by inserting a pin that is in close contact with the alignment hole into the alignment hole of the central member and the alignment hole of the side member.

  In the present embodiment, these constituent members are fixed using bolts penetrating the central member, the first side member, and the second side member. However, the present invention is not limited to this configuration. A center member and a side member can be fixed using a fixing member. For example, a through hole or a bag hole in which a thread groove is formed in the central member is formed. By inserting a bolt from the outside of the through hole of the first side member, the first side member can be fixed to the central member. Moreover, a 2nd side member can be fixed to a center member by inserting a volt | bolt from the outer side of the through-hole of a 2nd side member. Thus, each side member may be individually fixed to the central member. By this method, it is possible to more easily align the members and fix the members.

  In the manufacturing method according to the present embodiment, a quadrupole accelerator having a long axial length along the acceleration axis can be easily manufactured. For example, when a quadrupole accelerator having a long axial length is manufactured by brazing, the acceleration cavity must be disposed inside the high temperature furnace. For this purpose, a large high-temperature furnace is required. However, in the present embodiment, an accelerator that is long in the direction of the acceleration axis can be easily manufactured by integrally forming the central member and the side members.

  Moreover, in this Embodiment, the member and electrode which comprise the cylindrical part of an acceleration cavity are integrally formed. In the method of manufacturing the acceleration cavity, a method of fixing the electrode to the cylindrical portion with a bolt or the like after manufacturing the cylindrical portion and each electrode individually can be considered. However, in this method, the number of parts increases and it becomes difficult to align the constituent members. On the other hand, as in the present embodiment, the positioning can be easily performed by adopting the constituent members in which the respective electrodes and the members constituting the cylindrical portion are integrally formed. In addition, since the positional relationship between the cylindrical portion and the electrode is maintained during machining, the dimensional accuracy is increased, and a quadrupole accelerator excellent in electrical performance can be provided.

  In the quadrupole accelerator in the present embodiment, a region where the central member 11 and the first side member 12 are in contact with each other, and a region where the central member 11 and the second side member 13 are in contact with each other. In addition, a conductive member can be interposed. For example, instead of a rubber O-ring as a vacuum sealing member, a metal sealing member can be disposed. Alternatively, in addition to the concave portion in which the vacuum sealing member is disposed, a concave portion is additionally formed on at least one contact surface of the central member and the side member, and a conductive member such as a metal wire may be disposed in the concave portion. Absent.

  By fixing the central member 11 and the side members 12 and 13 via conductive members, the conductivity between the central member 11 and the respective side members 12 and 13 can be improved. Alternatively, desired electrical performance can be ensured.

  Further, when the quadrupole accelerator is operated, the temperature rises due to electric resistance. If the temperature rises greatly, the O-ring may be damaged. In such a case, damage to the sealing member can be avoided by employing a metal sealing member. For example, a metal vacuum sealing member is suitable for a quadrupole accelerator that operates continuously. The high frequency accelerator may include a cooling device for cooling the acceleration cavity. For example, a cooling pipe for flowing cooling water may be arranged inside the electrode or on the surface of the side member.

  The quadrupole accelerator in the present embodiment is formed so that the cross-sectional shape of the cylindrical portion is substantially a regular octagon, but is not limited to this form, and appropriate electrical performance as a quadrupole accelerator. Any shape that can be realized can be adopted. For example, the cylindrical portion can be formed so that the cross-sectional shape is a circle or an arbitrary polygon.

  In the present embodiment, the central member and the side member are formed from aluminum. However, the present invention is not limited to this, and the central member and the side member can be formed from any material. For example, in the preparation step, the constituent member can be formed from a solid copper material. Or you may employ | adopt the structural member which gave the copper plating to the surface of the member formed from arbitrary materials.

  In the respective drawings described above, the same or corresponding parts are denoted by the same reference numerals. In addition, said embodiment is an illustration and does not limit invention. Further, in the embodiment, changes included in the scope of claims are intended.

DESCRIPTION OF SYMBOLS 1 Acceleration cavity 2 Cylindrical part 11 Central member 11a Center outer frame part 12, 13 Side member 12a, 13a Side outer frame part 12b, 13b Wall part 21-24 Electrode 31 Reference mark 32 Alignment mark

Claims (6)

A central member including a central outer frame portion, a first electrode protruding inward from the central outer frame portion, and a second electrode protruding inward from the central outer frame portion;
The first side outer frame portion, the first wall portion extending outward from the first side outer frame portion and having a shape of a part of the acceleration cavity, and the first wall portion toward the inner side A first side member including a projecting third electrode and disposed on one side of the central member;
A second side outer frame portion, a second wall portion extending outward from the second side outer frame portion and having a shape of a part of the acceleration cavity, and an inward direction from the second wall portion A second side member including a projecting fourth electrode and disposed on the other side of the central member;
The central member, the first side member and the second side member are each integrally formed from one member,
The central member, the first lateral member, and the second lateral member are such that the central outer frame portion, the first lateral outer frame portion, and the second lateral outer frame portion are fixed by a fixing member. A characteristic quadrupole accelerator.   The quadrupole accelerator according to claim 1, wherein the central member, the first side member, and the second side member are fixed to each other via a conductive member. A central member including a central outer frame part, a first electrode protruding from the central outer frame part and a second electrode protruding from the central outer frame part, a first side outer frame part, and a shape of a part of the acceleration cavity A first side member including a first wall portion having a first wall portion and a third electrode projecting from the first wall portion, a second side outer frame portion, and a second shape having a part of the acceleration cavity. Preparing a second side member including a fourth electrode protruding from the wall portion and the second wall portion; and
The first side member and the second side member are arranged on both sides of the center member, and the center outer frame portion, the first side outer frame portion, and the second side outer frame portion are fixed to each other by a fixing member. Including an assembly process,
The preparing step includes a step of integrally forming each of the central member, the first side member, and the second side member from one member, and a method for manufacturing a quadrupole accelerator. The preparation step includes a step of forming a reference mark on the outer surface of the central member, and a step of forming alignment marks on the outer surface of the first side member and the outer surface of the second side member,
4. The method of manufacturing a quadrupole accelerator according to claim 3, wherein the assembling step includes a step of aligning the respective members by aligning the reference mark and the alignment mark. The preparation step includes a step of forming the first fitting portion on the central member, and a step of forming the second fitting portion on the first side member and the second side member,
The assembling step includes a step of aligning the respective members by fitting the first fitting portion and the second fitting portion to each other. A method of manufacturing a quadrupole accelerator. The preparation step includes a step of forming a first alignment hole in the central member, and a step of forming a second alignment hole in the first side member and the second side member,
The assembling step includes a step of aligning each member by inserting an alignment pin into the first alignment hole and the second alignment hole. A manufacturing method of the quadrupole accelerator as described.

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