JPS5820088B2 - The best klystron in the world - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tuning mechanism for inductively changing the resonant frequency of a cavity in a high power klystron.

It is well known that methods for changing the resonant frequency of a cavity can be roughly divided into a C tuning method that changes the capacitance component and an L tuning method that changes the inductive component.

For example, FIG. 1 is known as a typical C tuning system and FIG. 2 is a typical example of an L tuning system in the prior art.

In Fig. 1, 1 indicates a hollow cavity, 2 a drift tube, 3 a variable capacitance element, and 4 a bellows.
, 5 indicates a shaft, and as shown in the figure, the shaft 5 and the variable capacitance element 3 are integrated.

By moving the shaft 5 from the outside, the variable capacitance element 3 moves back and forth near the drift tube, and the capacitance of the cavity changes, thereby changing the resonance frequency.

In FIG. 2, a guide plate 6, which is a part of the wall constituting the cavity, is fixed to the end of the cavity via a telescopic plate 8. As shown in FIG.

By moving the shaft 5 from the outside, the position of the guide plate 6 changes, and the induction component of the cavity changes, thereby changing the resonance frequency.

By the way, the disadvantage of the C tuning method shown in Fig. 1 is that in addition to the capacitance of the cavity itself, the capacitance due to the addition of the capacitive plate 3 is added, so the actual capacitance increases and is expressed as The parallel impedance of the cavity decreases and the high frequency characteristics deteriorate.

In addition, in the conventional tuning method shown in FIG. 2, a slight gap 9 is created between the guide plate 6 and the upper and lower walls of the cavity due to the movement of the guide plate 6, and power leaks into the back space 10, where unnecessary power is lost. mode was sometimes excited.

In order to solve the above-mentioned drawbacks, it has been proposed to slide a coil spring with a full diameter between the upper and lower walls of the cavity.

However, the following drawbacks were found in this coil slider.

That is, it has been confirmed that the above structure has extremely good contact properties and operates stably as a klystron when the power level is low, but if this is applied to a high power klystron, the tungsten paper 12 will be heated. This caused a significant amount of gas to be generated, causing the tube to lose its function as a vacuum tube.

SUMMARY OF THE INVENTION In view of the above drawbacks of the prior art, it is an object of the present invention to provide a tuning mechanism that can be applied even to klystrons that amplify extremely large amounts of power.

Next, the present invention will be explained in detail with reference to the drawings.

In Fig. 3, a male screw part 1 made of copper, for example, with good heat conduction
Cut a part of 1 and use two round bar-shaped jigs 15.
For example, a tungsten wire 12 is wound along the thread with a constant tension, and then the jig 15 is removed to form a type of spring.

Next, both ends of the threaded portion 11 are fixed to the spring support 13 with screws 14.

The above-mentioned elements 11, 12, 13, and 14 are integrated to form a tuning element, which slides in contact between the upper and lower walls of the cavity to inductively change the resonant frequency of the cavity.

Although not shown, the spring support 13 is extended outside the vacuum container via a bellows, for example, and is driven from the outside.

Moreover, a molybdenum wire may be used instead of the tungsten wire 12.

The present invention is further characterized in that the surface of the tungsten wire 12 is plated with copper, gold, or nickel to form a kind of surface layer on the tungsten wire to suppress the generation of gas molecules.

Since the surface layer has an extremely low electrical resistance value compared to the base material,
This has the dual effect of reducing the amount of heat generated by the base material 12 and suppressing the generation of gas molecules from the base material.

Furthermore, in the male threaded portion 11, a square thread can be cut instead of a threaded thread, and tungsten tape can be used instead of the tungsten wire 12 to widen the contact area with the upper and lower walls of the cavity and improve heat dissipation. Conceivable.

Next, the effects of the present invention will be explained.

According to the present invention, even if the power level of the klystron becomes very high, the generation of gas molecules is extremely small, and a high-power klystron with high vacuum and high stability can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the conventional C tuning method, and FIG. 2 is a schematic configuration diagram showing the L tuning method. In both figures, a is a side sectional view and b is a horizontal sectional view. FIG. 3 shows the tuning element of the present invention, in which a is a side view as seen from the vertical direction and b is a side view seen from the horizontal direction. In the figure, 1 is a cavity, 3 is a variable capacitance element, 5 is a shaft, 6 is a guide plate, 11 is a male thread component, 12 is a tungsten wire, 13 is a support, and 15 is a round bar jig.

Claims (1)

[Claims] 1. An assembly in which a tungsten wire is wound in a helical coil shape along the thread groove of an element made by cutting out a part of the opposing outer periphery of a male screw of a certain length in a direction parallel to the axis is fixed to a shaft and resonates. A klystron tuning mechanism in which the resonant frequency of a resonant cavity is changed by sliding the parallel upper and lower walls of the cavity while short-circuiting the same, characterized in that a surface layer with low electrical resistance is formed on the helical coil. High power klystron tuning mechanism.