JPS63307699A - Accelerating resonance cavity - Google Patents

Abstract

PURPOSE:To obtain an accelerating resonance cavity which is small-sized and simple in structure by rotating movable panels centering one end to change the resonance frequency. CONSTITUTION:Movable panels 1d are arranged on the upper side and lower side of an accelerating electrode 1b, and its one end is rotatably supported with a driving shaft 1f. The movable panels 1d are rotated in the direction to change the distance from the accelerating electrode 1b when the driving shaft 1f is rotated. The resonance frequency of the accelerating resonance cavity 1 can be easily changed. When the movable panels 1d are rotated, a flexible panel 1e is bent, the movement of the movable panels 1d is absorbed, thus both end sections of a short circuit plate are not slid on the inner wall of a frame as experienced in the past. The accelerating resonance cavity which is small-sized and simple in structure can be thereby obtained.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an acceleration cavity resonator used in a particle accelerator, and in particular to an acceleration cavity resonator used in a separate sector cyclotron (hereinafter abbreviated as SSC). Regarding the body resonator.

[Prior Art] The SSC is equipped with a deflection device that deflects charged particles using a direct current magnetic field and rotates them, and an acceleration cavity resonator that accelerates the charged particles with a high-frequency accelerating electric field synchronized with the rotational motion. That is, the relationship between the rotational frequency fO of charged particles and the frequency f of the high-frequency accelerating electric field is expressed as f=kfo (
(k is an integer), the charged particles tend to be accelerated.

Here, FIG. 4 shows a conventional acceleration cavity resonator.

Referring to FIG. 4, a casing (outer box) 3 having a rectangular cross section with openings on the top and bottom surfaces has openings (not shown) formed in the substantially central wall thereof facing each other. One end of a pair of acceleration electrodes 4 is attached to the housing wall so as to sandwich this one opening, and the accelerations t[14 extend to the right in parallel with each other.

Further, one end of a pair of opposing electrodes 1i5 is attached to the housing wall so as to sandwich the other opening, and this opposing electrode 1i5 faces the accelerating pole 4 with a predetermined gap therebetween. The space defined by the accelerating electrode 4 and the counter electrode 5 becomes a path for the charged particle beam.

A shorting plate 6 is arranged above and below the accelerating electrode W14, and both ends of the shorting plate 6 slidably abut against the inner wall of the housing 3 and move in a direction perpendicular to the accelerating electrode 4. It is possible. That is, it is movable in the direction indicated by the dashed arrow.

When the charged particle beam passes as shown by the solid arrow in Figure 4, it accelerates by 1! Pole 4 and counter electrode 512! A high-frequency electric field is generated in the passage by a high-frequency signal applied to 1, and the charged particles are accelerated by this high-frequency electric field.

By the way, as mentioned above, the rotational motion frequency of charged particles and the frequency of the high-frequency accelerating electric field (the resonant frequency of the accelerating cavity resonator)
must be in sync with.

For this reason, the frequency of the high frequency accelerating electric field is changed by moving the shorting plate 6 in the direction shown by the broken line arrow to synchronize it with the rotational movement frequency of the charged particles.

[Problem to be Solved by the Invention 1] By the way, in the conventional accelerating cavity resonator, both ends of the shorting plate 6 slide on the inner wall of the casing 3, so that the shorting plate 6 and the casing 3 are connected to each other.
By moving it while maintaining electrical contact with
In effect, the length and height of the cavity are varied, thereby varying the resonant frequency of the accelerating cavity. In this way, in the conventional accelerating cavity resonator, the short circuit plate 6
Since both ends of the short-circuit plate 6 and the inner wall of the housing 3 slide, the contacts attached to both ends of the short-circuit plate 6 may wear out, the mechanism for driving the contacts becomes complicated, and the drive stroke of the short-circuit plate 6 may become complicated. There is a problem that the size of the image becomes larger and the overall size becomes larger.

The object of the present invention is to provide a compact accelerating cavity resonator of #4 construction.

[Means for solving the problems] According to the present invention, it is used in a particle accelerator such as SSC,
a housing, a pair of accelerating electrodes disposed at a predetermined interval within the housing, one end attached to the housing wall, extending in a predetermined direction, and defining a path through which charged particles pass; is attached to the wall of the casing, and a counter electrode that faces the accelerating electrode with a predetermined gap therebetween and defines the passage; , a movable panel arranged so as to be rotatable around one end so as to vary the distance from the accelerating electrode in order to change the resonance frequency of the accelerating cavity communicator; and the one end of the movable panel and the It has a flexible panel for electrically coupling it to the side wall of the housing, and the movable panel is rotated around the one end! There is obtained an acceleration cavity resonator characterized in that the resonance frequency is changed by driving with lJ.

[Examples] Examples of the present invention will be described below with reference to the drawings.

First, the SSC will be outlined with reference to FIG.

Four deflection waves rl12 are arranged at intervals of 90 degrees, and this deflection wave ff2 includes a return yoke 2a and a ball (magnetic pole) 2b. Further, an acceleration cavity resonator 1 is arranged between the polarized waves T12 at an angular interval of 180 degrees, and this acceleration cavity resonator 1 includes an outer box (housing) 1a, an acceleration electrode 1b, It has a movable panel 1d, a flexible panel 1e, and one drive shaft (rotation shaft).As shown in the figure, the charged particle beam is deflected by a deflection device 2, and an accelerating cavity resonator 1 It is accelerated and orbits around the orbit.

Here, the accelerating cavity resonator 1 will be explained in detail with reference also to FIG.

Openings (not shown) through which the charged particle beams enter and exit are formed in the side wall surface of the outer box (casing) Ia, facing each other, and in FIG. One ends of a pair of accelerating electrodes 1b are attached to the upper and lower walls of the outer box 1a, and the accelerating electrodes 1b extend parallel to each other to the right. Similarly, one end of a pair of opposing electrodes 1C is attached to the wall surface of the outer box 1a so as to sandwich the right opening, and this opposing electrode 1C faces the accelerating electrode 1b with a predetermined gap therebetween. The space defined by the accelerating electrode 1b and the counter electrode 1C becomes a path for the charged particle beam.

A movable panel 1d is arranged above and below the acceleration electrode 1b, one end of which is rotatably supported by a drive shaft 1f. That is, the movable panel 1d rotates one drive shaft as shown by the solid arrow in FIG. 1, thereby changing the distance from the accelerating electrode 1b in the direction shown by the solid arrow in FIG. ). One end of the movable panel 1d and the side wall of the outer box 1a are electrically connected (coupled) by the flexible panel 1e. As shown in FIG. 2, the movable panel 1d is at the position indicated by the broken line. If so, the frequency of the high-frequency accelerating electric field (resonant frequency of accelerating cavity resonator 1)
f is high, while at the position shown by the solid line, the frequency f is low. The drive shaft 1f is pulled out to the outside and rotated by a predetermined angle in an arbitrary direction around the shaft by a drive device such as a motor (not shown). Therefore, the resonant frequency f of the accelerating cavity resonator 1 can be easily changed. Further, when the movable panel 1d rotates, the flexible panel 1C bends accordingly, and the movement of the movable panel 1d is absorbed.

Therefore, unlike in the past, both ends of the shorting plate 6 do not slide against the inner wall of the casing 3, and the structure is simplified, and the contacts attached to both ends of the shorting plate 6 do not slide. Regular maintenance and replacement are not required.

When accelerating charged particles, the accelerating electrode 1b and the counter electrode 1
A high-frequency electric field is generated by utilizing a resonance phenomenon with carbon to accelerate charged particles. Accelerating electrode 1 moves movable panel 1d
The rotational frequency of the charged particles [O and the frequency of the high-frequency electric field T! Synchronize with Lf. At this time, the frequency f of the high-frequency electric field is changed by changing the capacitance C between the accelerating electrode 1b and the movable panel 1d. The equivalent circuit of the accelerating cavity resonator 1 of this embodiment is a parallel resonant circuit, as shown in FIG. 3, and the capacitance C can be changed by rotating the movable panel 1d. .

[Effects of the Invention] As explained above, according to the present invention, the acceleration cavity resonance In order to change the resonance frequency of the device, a movable panel is arranged so as to be rotatable around one end so as to change the distance from the accelerating electrode, and one end of this movable panel and the side wall of the housing are connected electrically. The structure has a flexible panel for coupling, and the resonant frequency is changed by rotating the movable panel around one end, making it possible to obtain a compact accelerating cavity resonator with a simple structure. This has the advantage of eliminating the need for regular maintenance and replacement of contacts.

[Brief explanation of drawings]

Figure 1 shows a separate sector cyclotron (SS
C), Figure 2 is a diagram schematically showing A-AIIF in Figure 1.
11 shows an embodiment of the accelerating cavity resonator according to the present invention, FIG. 3 shows an equivalent circuit of the accelerating cavity resonator of FIG. 2, and FIG. 4 shows a conventional accelerating cavity resonator. FIG. 1... Acceleration cavity resonator, 1a... Outer box (casing), 1
b... Accelerating electrode, 1C... Counter electrode, 1d... Movable panel, 1e... Flexible panel, 1f...
Drive shaft, 2... Deflection device, 2a... Return yoke, 2b... Ball (magnetic pole). Figure 2

Claims (1)

[Claims] 1. Used in a particle accelerator, including a casing, and a passageway through which charged particles pass, which is arranged at a predetermined interval within the casing, one end is attached to the wall of the casing, and extends in a predetermined direction. An acceleration cavity resonator comprising: a pair of accelerating electrodes defining the passage; and a counter electrode having one end attached to the housing wall, facing the accelerating electrodes with a predetermined gap therebetween, and defining the passage, a movable panel disposed outside the passage within the housing so as to be rotatable around one end so as to vary the distance from the accelerating electrode in order to change the resonance frequency of the accelerating cavity resonator; , a flexible panel for electrically coupling the one end of the movable panel and the side wall of the housing, and the resonant frequency is changed by rotating the movable panel about the one end. An accelerating cavity resonator characterized by: