JPH0735360Y2 - High frequency multipole accelerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a high-frequency multipole linear accelerator, which is a type of linear accelerator.

(Prior Art) FIG. 5 shows a cross-sectional structure of a conventional high-frequency multipole linear accelerator.

Inside the conductive acceleration cavity 2, four electrodes 4-1 to 4-4 are provided.
Are mounted so that their tips face the center of the acceleration cavity 2. Each of the electrodes 4-1 to 4-4 is attached to the acceleration cavity 2 by a screw 6 whose root portion is adjustable.

It is no exaggeration to say that the performance of the high-frequency multipole linear accelerator depends on the positional accuracy of the tips of the electrodes 4-1 to 4-4 forming the acceleration electric field. Therefore, the electrodes 4-1 to 4-4 can be accurately attached to the acceleration cavity 2, or the electrodes 4-1 to 4-1 can be accurately attached.
A mechanism such as a mounting screw 6 as a mechanism for adjusting the tip position of 4-4 has been proposed (see “IEEE Transactions
on Nuclear Science ", NS-30, Volume 4, 2975-2979
Page (1983), see pages 3585-3587 of the same magazine).

In the high frequency multipole linear accelerator, each electrode 4-
Not only the positional accuracy of the tips of 1 to 4-4 is required, but also sufficient electrical contact between the electrodes 4-1 to 4-4 and the acceleration cavity 2 is required. This is because a high-frequency large current flows through the connection between the electrodes 4-1 to 4-4 and the acceleration cavity 2. Therefore, as shown in FIG. 5, the electrodes 4-1 to 4-4 are also provided.
A groove is provided in the contact portion between the acceleration cavity 2 and the acceleration cavity 2, and an elastic metal pipe 8 called a contact pipe is interposed in the groove to maintain the electrical contact between the electrodes 4-1 to 4-4 and the acceleration cavity 2. ing.

(Problems to be Solved by the Invention) In the conventional high-frequency multipole linear accelerator, the electrodes 4-1 to 4-
Since the tip of No. 4 and the groove into which the contact type 8 is fitted are of an integral structure, the dimensions of the tips of the electrodes 4-1 to 4-4, the groove, and the inner surface of the acceleration cavity 2 are not processed with high accuracy.
When the positions of the tips of -1 to 4-4 are adjusted, the contact pipe 8 does not contact the grooves of the electrodes 4-1 to 4-4 and the acceleration cavity 2 uniformly, and the Q value decreases and the expected high frequency There is a problem that a required electric field cannot be obtained with electric power, or the contact pipe 8 is eventually burned due to local heat generation.

The present invention does not require high dimensional accuracy in the electrode root or the acceleration cavity, and even if the tip position of the electrode is adjusted, it is possible to obtain uniform electrical contact between the electrode and the acceleration cavity. The purpose is to provide a linear accelerator.

(Means for Solving the Problems) Referring to FIG. 1 to FIG. 4 showing an embodiment,
In the high-frequency multipole accelerator of the present invention, a mechanism 23 for adjusting the tip position is provided at a portion where the electrode 10 is attached to the acceleration cavity 12, and an electrical connection between the electrode 10 and the acceleration cavity 12 is provided at the root of the electrode 10. The contact member 24 for keeping contact is provided independently of the position adjusting mechanism 23.

(Operation) The tip position of the electrode 10 is adjusted by the adjusting mechanism 23.

Electrical contact between the electrode 10 and the acceleration cavity 12 is maintained by the contact member 24.

(Example) FIG. 1 shows one of four electrodes in one example. Therefore, in the present invention, four electrodes are attached to the acceleration cavity as shown in the figure.

Reference numeral 10 is an electrode, which is attached to the acceleration cavity 12 at its root. A mounting hole 13 is provided in the acceleration cavity 12, and a mounting boss 14 is fitted into the mounting hole 13 to
14 is attached to the bottom surface of the base of the electrode 10 by a mounting screw 16.

A mounting plate 18 is attached to the acceleration cavity 12 with a screw 20 so as to close the mounting hole 13 of the acceleration cavity 12 from the outside of the acceleration cavity 12, and a mounting boss 14 is fixed to the mounting plate 18 with a screw 22. Thus, the electrode 10 is fixed to the acceleration cavity 12 by the screws 16, 20, and 22 by the mounting boss 14 and the mounting plate 18.

The acceleration cavity 12 also has an adjusting screw 23 that penetrates from the outside to the inside.
Is provided, the tip of the adjusting screw 23 abuts on the bottom surface of the base portion of the electrode 10, and the tip position of the electrode 10 can be adjusted by rotating the adjusting screw 23.

On both sides of the base of the electrode 10, contact members 24, each of which has a proper size, are attached by mounting screws 26.

A groove is provided in the electrode 10 at a contact portion between the electrode 10 and the contact member 24, and the groove has elasticity as shown in FIG. 2 as a local contactor for keeping electric contact between the electrode 10 and the contact member 24. A metal pipe 28 is fitted.

An elastic metal pipe 30 is also interposed between the contact member 24 and the acceleration cavity 12 as a local contactor for maintaining electrical contact.

To attach the electrode 10 to the acceleration cavity 12 in this embodiment, first attach the attachment boss 14 to the electrode 10 with the attachment screw 16, insert the attachment boss 14 into the attachment hole 13 of the acceleration cavity 12, and attach it to the attachment plate 18. The electrode 10 is fixed to the acceleration cavity 12 by screws 20 and 22. Then, the adjustment screw 23
Adjust the tip position of 10.

After the position of the tip of the electrode 10 is determined, the contact pipes 28,3
0 is fitted and the contact member 24 is attached by the mounting screw 26.

As the local contacts for maintaining electrical contact, in addition to the pipe-shaped ones 28 and 30 shown in FIG. 2, for example, the one having a C-shaped cross section 32 shown in FIG. 3 and the one shown in FIG. A spring-shaped one 34 having a bent cross-sectional shape can be used.

Further, these contacts 28, 30, 32, 34 may be plated with a metal having high conductivity such as silver, gold or copper.

When the contacts 28, 30, 32, 34 are used, electrical contact between the contact member 24 and the electrode 10 and between the contact member 24 and the acceleration cavity 12 is further improved. And if the contacts 28,3
Even when 0, 32, and 34 are burnt out, the contact member 28 is removed by removing the contact member 24 while fixing the electrode 10.
32, 34 can be exchanged, so contacts 28, 30, 32, 34
Is easy to replace.

(Effect of the Invention) In the present invention, the electrode is attached to the accelerating cavity, the mechanism for positioning the tip of the electrode by the adjusting mechanism for adjusting the tip position, and the contact member for maintaining the electrical contact between the electrode and the accelerating cavity. Since and are assembled as separate bodies, sufficient electrical contact between the electrode and the acceleration cavity can be obtained even if the position of the electrode tip is adjusted.

If the resonance frequency deviates from the design value when initially assembled, it is possible to deal with it only by processing the contact member without reworking the entire electrode.

[Brief description of drawings]

FIG. 1 is a perspective sectional view showing one electrode portion in one embodiment, FIGS. 2, 3, and 4 are perspective sectional views showing a contact in each embodiment, and FIG. 5 is a conventional high frequency wave. It is sectional drawing which shows a multipolar linear accelerator. 10 …… electrode, 12 …… accelerating cavity, 23 …… adjustment screw, 24 ……
Contact member, 28,30,32,34 ... Contactor.

Claims (1)

[Scope of utility model registration request] 1. A high-frequency multipole accelerator for accelerating charged particles by mounting a plurality of electrodes at their roots in a conductor accelerating cavity and accelerating charged particles by forming an accelerating electric field by the tip shape of these electrodes. Is attached to the acceleration cavity from the outside of the acceleration cavity abutting the bottom surface of the root of each electrode, a mechanism is provided to adjust the tip position of the electrode by pushing the bottom surface of the electrode root, Contact members are detachably attached to both sides of the base of each electrode of the acceleration cavity, and elastic contacts are provided between the contact member and the electrode and between the contact member and the inner wall surface of the acceleration cavity. And an electrode and an inner wall surface of the acceleration cavity are in electrical contact with each other via the contactor and the contact member.