JPH0758501A - Joint method for rf cavity resonator - Google Patents

Abstract

PURPOSE:To provide an RF cavity resonator jointing method that sure vacuum seal performance, proper RF contact face pressure and a jointing force with high stiffness are obtained at a jointing part of an RF cavity resonator. CONSTITUTION:Flat contact faces 3a, 3b, slightly recessed narrow grooves 4a, 4b and much recessed wide grooves 5a, 5b are formed over an entire circumference of a ridge face of cavities 2a, 2b to be jointed from the inner circumferential side. Then the contact faces 3a, 3b are butted to implement RF contact, a diaphragm 6a(6b) is fitted to the narrow groove 6a(6b) and continuous entire circumference welding 7 is applied to the entire circumference of the outer ridges to make vacuum sealing and plural tabs 8 are inserted between the wide grooves 5a, 5b on the circumference and welding 9 is applied to both end ridges to obtain jointing stiffness and a contact pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RF cavity resonator coupling method applied to coupling between cavities of an RF cavity resonator used in an RF mode in which a current flows through a cavity wall surface.

[0002]

2. Description of the Related Art Conventionally, when coupling cavities in an RF cavity resonator, a longitudinal sectional view of FIG.
As shown in the side view and the enlarged view of (C), the RF cavity resonator 1
The metal gasket 12 is interposed between the facing edge surfaces of the cavities 2a, 2b to be combined to form the flanges 13a, 13b of the outer edges and the bolts 14 and the nuts 1.
5, a method for obtaining a structure for applying a vacuum seal load and an RF contact pressure to the metal gasket 12 by utilizing the fastening force, and FIG. 3 (A) longitudinal sectional view, (B) side view, (C)
As shown in the enlarged view, the cavities 2a and 2b to be combined are formed.
RF contact surfaces 1 engaging each other on opposite edge surfaces of the
7 is formed and continuous welding 18 is applied to the outer peripheral edge to obtain a structure for applying a vacuum sealing by welding and a structural coupling force utilizing the shrinkage force of the welding and an RF contact pressure.

However, in the method of FIG. 2, there is a gap 16 between the edge surfaces as shown in FIG. 2C, and the current flowing through the wall surface of the cavity flows between the wall surface of this gap 16 and the gasket surface, so that there is a gap 16. The RF loss is large as compared with the hollow structure. Further, in the method of FIG. 3, the cavity joining by the all-round continuous welding 18 must exhibit the three functions of the vacuum seal of the cavities 2a and 2b, the RF contact, and the cavity fastening, but welding conditions satisfying the three functions are required. It is very difficult to establish. If the welding connection is too strong, the RF contact surface 17 is deformed, and if it is weak, the RF contact pressure cannot be obtained. In either case, the RF loss increases and the RF phase shift occurs.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances, and provides a reliable vacuum sealing property and an appropriate RF contact surface pressure and rigidity at the coupling portion of the RF cavity resonator. It is an object of the present invention to provide an RF cavity resonator coupling method capable of obtaining a high fastening force.

[0005]

Therefore, according to the present invention, a flat contact surface, a slightly recessed narrow groove portion, and a more recessed wide groove portion are provided from the inner peripheral side along the entire circumference of the end surface of the cavity to be joined. 3 parts are formed, RF contact is made by abutting the contact surfaces with each other, diaphragms are attached to the narrow groove portions, and outer edges of the narrow groove portions are continuously welded all around to perform vacuum sealing. It is characterized in that a plurality of tabs are provided on the circumference and welded to both end edges to obtain a joint rigidity and a contact pressure.

[0006]

In the RF cavity resonator coupling method of the present invention, the flatness of the cavity coupling portion is improved by providing the flat contact surface formed in the portion close to the cavity inner peripheral surface with accuracy and roughness such that the contact rate becomes higher. A high RF contact surface pressure can be obtained. Then, the outer edges of the diaphragm, the inner edge of which is previously welded to the narrow groove portion of the cavity to be joined, are continuously welded around the entire circumference, and the cavity is vacuum-sealed. At this time, since the diaphragm is thin, a force that deforms other parts is not generated by this welding. However, the shape and thickness of the diaphragm must not buckle under atmospheric pressure. After that, leave a slight gap between the edge of the tab and the wide groove part, weld a plurality of tabs to the wide groove part, and use the welding shrinkage to fasten the cavities together and weld shrinkage of the tab. Applies RF contact surface pressure to the cavity contact surface.
The size, quantity, and penetration depth of the tabs to be welded should be established in advance in the cavity specimen.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the RF cavity resonator coupling method of the present invention will be described with reference to the drawings. FIG. 1 illustrates the outline of the method, and FIG. 1A is a partial longitudinal sectional view of the RF cavity resonator. FIG. 2B is a side sectional view, FIG. 2C is an enlarged view of a portion C of FIG.
FIG. 3D is a view from the direction of arrow D of FIG. In the above figure,
In the cavities 2a and 2b to be coupled to form the RF cavity resonator 1, contact surfaces 3a and 3b that are flat from the inner peripheral side, narrow groove portions 4a that are slightly recessed from the inner peripheral side, respectively, along the entire circumference of the edge surface of the coupling portion. 4b, wide groove portions 5a, 5b that are more recessed are formed, and diaphragms 6a, 6b are welded in advance to the inner edges of the narrow groove portions 4a, 4b, respectively.

In coupling the cavities 2a and 2b with each other, the edge surfaces of the coupling portion are opposed to each other and the contact surface 3 is formed.
a and 3b are butted against each other to make an RF contact, and first, the diaphragm 6a, which is pre-welded to the narrow groove portions 4a and 4b,
The outer periphery of 6b is continuously welded around the entire circumference 7 and vacuum-sealed. At this time, since the diaphragms 6a and 6b are sufficiently thin, the contraction caused by the continuous welding 7 does not generate an attractive force that deforms the contact surfaces of the contact surfaces 3a and 3b. Next, after performing a vacuum leak test on the joint portion of the diaphragms 6a and 6b and confirming that there is no defect in the welding, the RF input antenna 10 and the RF detection probe 11 are attached to the cavities 2a and 2b, and the RF cavity resonator 1 is formed. Set up Q-factor measurements to check performance.

Next, while measuring the Q factor of the RF cavity resonator 1 constructed as described above, a plurality of tabs 8 are provided over the entire circumference in the wide groove portions 5a, 5b so that both end edges and the wide groove portions 5a, 5b are formed.
Weld 9 to. The tab 8 is welded 9 to the wide groove portions 5a and 5b.
When the molten portion cools and solidifies, the cavities 2a and 2b attract each other due to the contraction, and the cavities 2a and 2b are attracted to each other.
Is also a force that applies contact surface pressure to the contact surfaces 3a and 3b. Therefore, the attraction force changes depending on the weld penetration depth of the tab 8, the size of the tab 8, the number of tabs 8, and the contact rate varies depending on the surface roughness and flatness of the contact surfaces 3a and 3b and the attraction force of the tab 8. However, in order to strengthen the fastening force of the cavities 2a and 2b by setting conditions for these changing elements in advance by the test piece, the contact surface 3
The contact areas of a and 3b are expanded, the number of tabs 8 is increased, or the size of tabs 8 is increased or the weld penetration is deepened. Which is selected depends on the size of the cavities 2a and 2b. The tab 8 is welded until a predetermined Q value is obtained.

Thus, according to this coupling method, since it is made of all metal, the vacuum characteristic is excellent, and the current flows without passing through the gasket, so that the RF loss is small and the fastening force can be controlled. It is possible to obtain a stable RF cavity resonator with very little fear of RF phase shift or discharge.

[0011]

In summary, according to the present invention, the contact surface which is flat from the inner peripheral side, the narrow groove portion which is slightly recessed, and the wide groove portion which is more recessed are formed along the entire circumference of the edge surface of the cavity to be joined.
Form a part and butt the contact surfaces together and RF
Make a contact, attach a diaphragm to each of the narrow grooves, perform continuous welding around the outer edges of each other, and perform vacuum sealing.Furthermore, place a plurality of tabs on the circumference between the wide grooves, and attach to both edges. An RF cavity resonator capable of obtaining a reliable vacuum sealing property, an appropriate RF contact surface pressure, and a fastening force with high rigidity at a coupling portion of an RF cavity resonator by performing welding to obtain a coupling rigidity and a contact pressure. The present invention is extremely industrially beneficial because it provides a coupling method.

[Brief description of drawings]

1A and 1B show an embodiment of an RF cavity resonator coupling method according to the present invention, wherein FIG. 1A is a partial vertical sectional view of an RF cavity resonator coupled by this method, and FIG. , (C) is an enlarged view of part C in (A), and (D) is D in (A).
FIG.

2A and 2B show a conventional RF cavity resonator coupling method, wherein FIG. 2A is a partial vertical cross-sectional view of the RF cavity resonator, FIG. 2B is a side view, and FIG. It is a C section enlarged view.

FIG. 3 shows another conventional coupling method, in which FIG.
FIG. 2B is a side view and FIG. 2C is an enlarged view of part C of FIG. 3A.

[Explanation of symbols]

 1 RF cavity resonator 2a, 2b Cavity 3a, 3b Contact surface 4a, 4b Narrow groove part 5a, 5b Wide groove part 6a, 6b Diaphragm 7 Full circumference continuous welding 8 Tab 9 Welding 10 RF input antenna 11 RF detection probe

Claims (1)

[Claims] 1. A flat contact surface, a narrow groove portion that is slightly recessed, and a wide groove portion that is recessed more are formed on the entire circumference of the edge surface of the cavity to be joined, and the contact surfaces are joined to each other. To make RF contact, attach diaphragms to the narrow grooves, and continuously weld the outer edges of each other all around to perform vacuum sealing. Further, insert a plurality of tabs on the circumference between the wide grooves. An RF cavity resonator coupling method, characterized in that the both ends are welded together to obtain coupling rigidity and contact pressure.