JP2008117667A - Cavity shape adjusting device and acceleration cavity frequency adjusting device - Google Patents

Abstract

A compact and simple cavity shape adjusting device and acceleration cavity frequency adjusting device capable of finely adjusting the frequency in the cavity without moving a rod in the cavity.
In a frequency adjusting device, a substantially concave space portion is locally provided in a wall portion 2a forming a cavity S, thereby forming a shape variation portion 30 involved in resonance frequency adjustment of the cavity S. At the same time, the shape changing portion 30 is changed in shape by the rotation operation portion 32 provided in the space portion 35.
[Selection] Figure 3

Description

  The present invention relates to a shape adjusting device for finely adjusting the surface shape of various cavities formed of a metal material, and more particularly to a frequency adjusting device for adjusting an acceleration cavity frequency.

  Conventionally, a high-frequency electron gun has been used as a source for generating an electron beam incident on an electron synchrotron. The high-frequency electron gun includes a high-frequency accelerating cavity that is cylindrical and has a cavity formed therein, a cathode is attached to one end of the high-frequency accelerating cavity, and an electron beam emission port is formed at the other end . Then, a high frequency electric field is formed in the cavity by the high frequency supplied from the high frequency supply port formed on the side surface of the high frequency acceleration cavity, and electrons generated at the cathode are extracted by this high frequency electric field and accelerated to emit an electron beam. The light is emitted from the port.

By the way, the resonance frequency of the high-frequency accelerating cavity of the high-frequency electron gun is delicately adjusted, and it is necessary to change the resonance frequency according to the use situation. Since the resonance frequency of the high-frequency acceleration cavity is determined by the dimensions of the internal cavity, a resonance frequency adjusting device that deforms the shape of the internal cavity has been proposed (for example, see Patent Document 1). In the resonance frequency adjusting device described in Patent Document 1, a port is opened on a side wall of a high-frequency acceleration cavity, and a rod is inserted into and removed from the cavity by a linear introduction machine.
JP 05-29097 A

  However, the conventional resonance frequency adjusting device has a problem that the linear introduction machine, which is a mechanism for moving the rod in the high frequency acceleration cavity, is large and complicated.

  The present invention allows the shape of the cavity to be deformed without moving the rod in the cavity, and thereby the frequency of the cavity can be fine-tuned. It is an object of the present invention to provide an adjusting device and a frequency adjusting device for an acceleration cavity.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a shape adjusting device for adjusting the shape of a cavity, wherein the wall portion that forms the cavity on the inner side is directed from the outer surface toward the inner surface. By providing a substantially concave space portion, a shape variation portion formed between the space portion and the inner surface of the wall portion, the shape of which varies, and the shape variation portion disposed in the space portion, A rotation operation unit for changing the shape, and a force conversion mechanism for converting an operation force in the rotation direction of the rotation operation unit into a force in a linear direction and acting on the shape change unit.

  According to the first aspect of the present invention, the wall portion forming the cavity is locally provided with a substantially recessed space portion, thereby forming the shape variation portion involved in the cavity shape adjustment, and Since the shape changing part is changed by the rotation operation part provided in the space part, the shape of the cavity can be changed locally with a simple and compact inexpensive configuration, and fine shape adjustment is effectively performed. It becomes possible to do.

  In the above configuration, the direction of action of the force applied to the shape changing portion by the force conversion mechanism may be only one direction or both directions.

  Further, in the invention described in claim 2, in the invention described in claim 1, the force conversion mechanism is configured so that the shape changing portion protrudes and retracts with respect to the inside of the cavity by the force in the linear direction. The shape is varied.

  According to the invention described in claim 2, the same effect as that of the invention described in claim 1 can be obtained, and the shape is changed so that the shape changing portion protrudes and sinks with respect to the inside of the cavity. Therefore, the volume of the cavity can be changed in a wide range by the shape variation in both directions.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the force conversion mechanism uses a pitch difference between two screw portions arranged coaxially. It comprises a differential screw mechanism that pushes and pulls the shape variation portion according to the rotation of the rotation operation portion.

  According to the invention described in claim 3, since the same effect as that of the invention described in claim 1 or 2 can be obtained and the principle of the differential screw is adopted, the rotary operation unit It is possible to easily and efficiently convert the operation force in the rotational direction into a force in the linear direction and to act on the shape variation portion.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the differential screw mechanism is formed on the outer periphery of an extending portion that extends integrally from the shape varying portion into the space portion. A first screw portion that is formed and screwed to a screw formed on an inner peripheral surface of the rotation operation portion, and is coaxially arranged with the first screw portion in a state of being fixed to the wall portion. The second screw portion is formed at a pitch different from the pitch of the first screw portion, and has a second screw portion screwed with a screw formed on the outer peripheral surface of the rotation operation portion. .

  According to the fourth aspect of the invention, the same effect as that of the third aspect of the invention can be obtained, and the movable side formed of the shape varying portion and the fixed side integral with the wall portion can be screwed respectively. Since the differential screw mechanism that provides the part is adopted, the shape changing part can be screwed forward and backward with a small number of parts, and the shape changing part is held at a predetermined changing position (shape adjusting position) ( It is possible to make a shape adjustment that is resistant to vibration and impact and has good stability.

  In the configuration of claim 4, the second screw portion may be formed directly on the wall portion (inner surface of the space portion) or on a separate member fixed to the wall portion. It may be formed.

  The invention described in claim 5 is a frequency adjusting device for adjusting a resonance frequency of an acceleration cavity for accelerating charged particles, wherein the acceleration cavity is formed on the inner wall from the outer surface to the inner surface. By providing a substantially concave-shaped space portion toward the surface, a shape varying portion that is formed between the space portion and the inner surface of the wall portion, the shape of which varies, and the shape variation disposed in the space portion. A rotation operation unit for changing the shape of the part, and a force conversion mechanism for converting an operation force in the rotation direction of the rotation operation unit into a force in a linear direction and acting on the shape change unit. .

  According to the fifth aspect of the present invention, the wall portion forming the acceleration cavity is locally provided with a substantially concave space, thereby forming the shape variation portion involved in adjusting the resonance frequency of the acceleration cavity. In addition, since the shape changing portion is changed by the rotation operation portion provided in the space portion, the shape of the acceleration cavity is locally changed with a simple, compact and inexpensive configuration, and the resonance frequency of the acceleration cavity is changed. Can be fine-tuned. Further, since the space portion does not reach the acceleration cavity, for example, an ultrahigh vacuum atmosphere in the acceleration cavity is not affected.

  Further, in the invention described in claim 6, in the invention described in claim 5, the force conversion mechanism causes the shape variation portion to protrude and retract with respect to the inside of the acceleration cavity by the force in the linear direction. It is characterized in that the shape is varied.

  According to the invention described in claim 6, the same effect as that of the invention described in claim 5 can be obtained, and the shape is changed so that the shape changing portion protrudes and sinks with respect to the inside of the acceleration cavity. Therefore, the volume of the acceleration cavity can be changed in a wide range by the shape variation in both directions, and therefore the resonance frequency of the acceleration cavity can be adjusted in a wide range.

  Further, in the invention described in claim 7, in the invention described in claim 5 or 6, the force conversion mechanism uses a pitch difference between two screw portions arranged coaxially. It comprises a differential screw mechanism that pushes and pulls the shape variation portion according to the rotation of the rotation operation portion.

  According to the invention described in claim 7, since the same effect as that of the invention described in claim 5 or 6 can be obtained and the principle of the differential screw is adopted, the rotary operation unit It is possible to easily and efficiently convert the operation force in the rotational direction into a force in the linear direction and to act on the shape variation portion.

  The invention described in claim 8 is the invention described in claim 7, wherein the differential screw mechanism is provided on an outer periphery of an extending portion that extends integrally from the shape varying portion into the space portion. A first screw portion that is formed and screwed to a screw formed on an inner peripheral surface of the rotation operation portion, and is coaxially arranged with the first screw portion in a state of being fixed to the wall portion. The second screw portion is formed at a pitch different from the pitch of the first screw portion, and has a second screw portion screwed with a screw formed on the outer peripheral surface of the rotation operation portion. .

  According to the eighth aspect of the invention, the same effect as that of the seventh aspect of the invention can be obtained, and the movable side formed by the shape changing portion and the fixed side integral with the wall portion can be screwed respectively. Since the differential screw mechanism that provides the part is employed, it is possible to realize the screw advance / retreat operation of the shape changing part with a small number of parts, and the shape changing part at a predetermined changing position (predetermined frequency adjusting position). It can be held (fixed), and it is possible to perform frequency adjustment that is strong against vibration and impact and has good stability.

  According to the present invention, it is possible to change the surface shape of the cavity without moving the rod in the cavity, and it is possible to finely adjust the frequency in the cavity, thereby making the cavity small and simple in structure. The shape adjusting device and the frequency adjusting device for the acceleration cavity can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  1 and 2 show a high-frequency accelerating cavity main body 1 of a high-frequency electron gun provided with a frequency adjusting device 10 according to an embodiment of the present invention. As shown in the figure, the acceleration cavity body 1 includes a housing 2 including a wall portion 2a that forms a cavity (acceleration cavity) S for accelerating charged particles. A guide member 6 for guiding a cathode (not shown) is attached to the housing 2. A waveguide 8 extends from the high frequency supply port of the housing 2 in one direction. The housing 2 is provided with an electron beam exit port 12 facing the guide member 6, and an acceleration tube (not shown) is attached to the electron beam exit port 12.

  Accordingly, in such a configuration, a high frequency electric field is formed in the cavity S by the high frequency supplied from the waveguide 8, and electrons generated at the cathode are drawn out and accelerated by the high frequency electric field, and the electron beam emission port 12 is emitted.

  The housing 2 (wall portion 2a) is made of oxygen-free copper, for example. In addition, a viewport tube 14 for observing the inside of the cavity S from the outside is attached to the housing 2.

  In the present embodiment, the frequency adjusting device 10 is installed at a plurality of locations of the housing 2. As clearly shown in FIG. 2, these frequency adjusting devices 10 are arranged symmetrically and radially with respect to the center O of the cavity S, for example.

  As shown in detail in FIG. 3, each frequency adjusting device 10 is for adjusting the resonance frequency of the cavity S, and has a shape changing portion 30 whose shape is changed. The shape changing portion 30 is formed between the space portion 35 and the inner surface 22 of the wall portion 2a by providing a substantially concave space portion 35 from the outer surface 20 toward the inner surface 22 in the wall portion 2a. In the present embodiment, the shape variation portion 30 is formed to have a thickness of 1 mm (= W), for example, in order to facilitate the shape variation and to ensure a predetermined strength.

  Further, the frequency adjustment device 10 has a rotation operation unit 32 in the space 35 for changing the shape of the shape changing unit 30. The rotation operation unit 32 is made of brass, for example, and is configured as a cylindrical shaft member. Further, M5 female screws 32a are formed at a predetermined first pitch (for example, 0.5 mm pitch) on the inner peripheral surface of the rotation operation unit 32, and M10 male screws are formed on the outer peripheral surface of the rotation operation unit 32. 32b is formed at a predetermined second pitch (for example, 0.75 mm pitch) different from the first pitch, preferably larger than the first pitch.

  Further, the frequency adjusting device 10 includes a force conversion mechanism 50 for converting the operation force in the rotation direction of the rotation operation unit 32 into a force in the linear direction and acting on the shape changing unit 30. The force conversion mechanism 50 changes the shape so that the shape changing part 30 protrudes and sinks with respect to the inside of the cavity S by the force in the linear direction. In particular, in the present embodiment, two force arranged coaxially are arranged. It is composed of a differential screw mechanism that pushes and pulls the shape variation portion 30 in accordance with the rotation of the rotation operation portion 32 by utilizing the pitch difference between the screw portions.

  Specifically, the force conversion mechanism 50 is disposed coaxially with the push-pull screw member 51 as an extending portion that extends integrally from the shape changing portion 30 into the space 35 and the push-pull screw member 51. And a fixing screw member 52 fixed to the wall 2a. The push-pull screw member 51 has a first screw portion 51 a formed on the outer peripheral surface thereof, and is inserted so as to be able to advance and retreat in a state of being coaxially and screwed into the inner hole of the rotation operation portion 32. That is, the first screw portion 51a is screwed with the female screw 32a of the rotation operation portion 32, and is configured as an M5 male screw formed at the first pitch (for example, 0.5 mm pitch). .

  On the other hand, the fixing screw member 52 is formed as a cylindrical member made of stainless steel, for example. In the present embodiment, the fixing screw member 52 is fitted into a cylindrical welding spacer 58 fixed to the wall portion 2a and is welded to the welding spacer 58 in that state. The welding spacer 58 is made of, for example, stainless steel, and is fitted into the space portion 35 and brazed to the wall portion 2a (the inner surface of the space portion 35).

  The fixed screw member 52 has a second screw portion 52a formed on the inner peripheral surface thereof, and the rotary operation portion 32 is inserted coaxially into the inner hole so as to be able to advance and retract in a screwed state. . That is, the second screw portion 52a is screwed with the male screw 32b of the rotation operation portion 32, and is configured as an M10 female screw formed at the second pitch (for example, 0.75 mm pitch). .

  In the configuration as described above, when the rotation operation unit 32 is rotated, the push-pull screw member 51 is pushed and pulled by a traction force or a pressing force according to a screw pitch difference between the first screw portion 51a and the second screw portion 52a. As a result, the shape changes so that the shape changing portion 30 protrudes and sinks with respect to the inside of the cavity S. Specifically, for example, when the rotation operation unit 32 is rotated clockwise, the push-pull screw member 51 is pushed out, whereby the shape changing unit 30 protrudes into the cavity S, and the volume of the cavity S is increased by that amount. Decrease. Therefore, the resonance frequency of the cavity S increases. On the other hand, when the rotation operation part 32 is rotated counterclockwise, the push-pull screw member 51 is pulled, whereby the shape changing part 30 is retracted from the cavity S or is substantially concave (arc-shaped) in the space part 35. The volume of the cavity S is increased by that amount. Therefore, the resonance frequency of the cavity S is reduced.

  An experimental result quantitatively showing an example of the frequency adjustment by the shape changing unit 30 is shown in a graph in FIG. In this figure, a frequency change of 220 kHz is obtained by one rotation. The vertical axis of the graph is the frequency change Δf with respect to a predetermined frequency f (= 2852360 kHz), and the horizontal axis is the rotation speed of the rotation operation unit 32. Here, the clockwise rotation direction is represented by plus, and the counterclockwise rotation direction is represented by minus.

  As described above, in the frequency adjusting device 10 according to the present embodiment, the wall portion 2a forming the cavity S is locally provided with the substantially recessed space portion 35, thereby contributing to the resonance frequency adjustment of the cavity S. While forming the fluctuation | variation part 32, the shape fluctuation | variation part 30 is made to fluctuate by the rotation operation part 32 provided in the space part 35. FIG. Therefore, the resonant frequency of the cavity S can be finely adjusted by locally changing the shape of the cavity S with a simple and compact inexpensive configuration. Further, since the space portion 35 does not reach the cavity S, for example, an ultrahigh vacuum atmosphere in the cavity S is not affected.

  Further, in the present embodiment, since the shape changing portion 30 is changed in shape so as to protrude and retract with respect to the inside of the cavity S, the volume of the cavity S can be changed in a wide range by the shape change in both directions. The resonance frequency of the cavity S can be adjusted in a wide range.

  Further, in this embodiment, since the principle of differential screw is adopted, the operation force in the rotational direction of the rotation operation unit 32 is easily and efficiently converted into a linear force with a compact configuration, and the shape changing unit. 30 can be applied.

  Further, in the present embodiment, the differential screw provided with screw portions 51a and 52a on the movable side (push / pull screw member 51) including the shape changing portion 30 and the fixed side (fixed screw member 52) integrated with the wall portion 2a, respectively. Since the mechanism is employed, the shape changing portion 30 can be screwed forward / backward with a small number of parts, and the shape changing portion 30 is held (fixed) at a predetermined change position (predetermined frequency adjustment position). It is possible to perform frequency adjustment that is resistant to vibration and impact and has good stability. Of course, in order to ensure the frequency adjustment hold, the rotation operation unit 32 may be fixed by, for example, a double nut after the frequency adjustment.

  Needless to say, the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the scope of the invention. For example, in the above-described embodiment, the frequency adjustment device 10 is installed with respect to the cavity main body 1 of the electron emission portion of the electron gun, but the frequency adjustment device 10 may be installed in the middle of the acceleration tube. In the above-described embodiment, the second screw portion 52a is provided on the fixing screw member 52 fixed to the wall portion 2a side. However, the second screw portion is provided directly on the wall portion. It doesn't matter. In that case, the fixing screw member 52 and the welding spacer 58 can be eliminated, and the second screw portion can be formed on the inner peripheral surface of the space portion 35. In the embodiment described above, the direction of action of the force applied to the shape changing unit 30 by the force conversion mechanism 50 is both directions (push and pull directions), but it may be only one direction. In that case, for example, force only in the pressing direction is applied to the shape changing portion 30 by the force conversion mechanism 50, and when the pressing force is released, the shape changing portion 30 is returned to the original shape by the restoring force. It may be like this. The frequency adjusting device 10 can also be applied to a cavity other than the acceleration cavity. In that case, the frequency adjusting device 10 simply functions as a shape adjusting device for adjusting the shape of the cavity.

1 is a side view of a high-frequency accelerating cavity main body of a high-frequency electron gun in which a frequency adjusting device according to an embodiment of the present invention is installed. It is a top view including the partial cross section of the high frequency acceleration cavity main body of FIG. It is sectional drawing of a frequency adjusting device. It is a graph of the experimental result which showed quantitatively an example of the frequency adjustment by a shape fluctuation | variation part.

Explanation of symbols

2a Wall 10 Frequency adjusting device (shape adjusting device)
DESCRIPTION OF SYMBOLS 30 Shape variation part 32 Rotation operation part 35 Space part 50 Force conversion mechanism 51a 1st screw part 52a 2nd screw part S Acceleration cavity

Claims (8)

A shape adjusting device for adjusting the shape of a cavity,
The shape of the wall formed between the space portion and the inner surface of the wall portion is changed by providing a substantially concave-shaped space portion from the outer surface toward the inner surface of the wall portion that forms the cavity inside. A shape variation part;
A rotation operation unit arranged in the space and for changing the shape of the shape changing unit;
A force conversion mechanism for converting an operation force in the rotation direction of the rotation operation unit into a force in a linear direction and acting on the shape variation unit;
A shape adjusting device comprising:   The shape adjusting device according to claim 1, wherein the force conversion mechanism changes the shape so that the shape changing portion protrudes and sinks with respect to the inside of the cavity by the force in the linear direction.   The force conversion mechanism includes a differential screw mechanism that pushes and pulls the shape variation portion according to the rotation of the rotation operation portion by using a pitch difference between two screw portions arranged coaxially. The shape adjusting device according to claim 1 or 2. The differential screw mechanism is
A first screw portion that is formed on the outer periphery of an extending portion that extends integrally from the shape changing portion into the space portion, and that is screwed with a screw formed on an inner peripheral surface of the rotation operation portion;
It is arranged coaxially with the first screw portion in a fixed state with respect to the wall portion, and is formed at a pitch different from the pitch of the first screw portion, and is formed on the outer peripheral surface of the rotation operation portion. A second threaded portion that engages with the threaded screw;
The shape adjusting device according to claim 3, wherein A frequency adjustment device for adjusting a resonance frequency of an acceleration cavity for accelerating charged particles,
The shape of the wall formed between the space portion and the inner surface of the wall portion is changed by providing a substantially concave-shaped space portion from the outer surface toward the inner surface of the wall portion forming the acceleration cavity on the inner side. A shape variation part,
A rotation operation unit arranged in the space and for changing the shape of the shape changing unit;
A force conversion mechanism for converting an operation force in the rotation direction of the rotation operation unit into a force in a linear direction and acting on the shape variation unit;
A frequency adjusting device comprising:   The frequency adjusting device according to claim 5, wherein the force conversion mechanism changes the shape so that the shape changing portion protrudes and sinks with respect to the inside of the acceleration cavity by the force in the linear direction.   The force conversion mechanism includes a differential screw mechanism that pushes and pulls the shape variation portion according to the rotation of the rotation operation portion by using a pitch difference between two screw portions arranged coaxially. The frequency adjusting device according to claim 5 or 6. The differential screw mechanism is
A first screw portion that is formed on the outer periphery of an extending portion that extends integrally from the shape changing portion into the space portion, and that is screwed with a screw formed on an inner peripheral surface of the rotation operation portion;
It is arranged coaxially with the first screw portion in a fixed state with respect to the wall portion, and is formed at a pitch different from the pitch of the first screw portion, and is formed on the outer peripheral surface of the rotation operation portion. A second threaded portion that engages with the threaded screw;
The frequency adjusting device according to claim 7, comprising:

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