JPS6059633A - Microwave tube - Google Patents

Abstract

PURPOSE:To obtain a durable collector by subdividing a radiator radially located outside an annular or conical annular collector core. CONSTITUTION:A radiator is subdivided in the direction of the tube axis and the direction perpendicular to the above direction so as to make the machanical rigidity of the radiator remarkably lower than that of a collector core. For example, the dimension (a) in the circumference direction of each subdivided radiator section is adjusted to be below about 1/2 of the thickness (t) of the collector core while the longitudinal dimension (b) is adjusted to be below about two times the thickness (t). As a result, the concentration of thermal stress is alleviated thereby obtaining a collector for a long-pulse superhigh-power microwave tube having a notably higher durability than the conventional one.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a collector for a straight beam type ultra-high power microwave tube.

The main components are a high-power microwave tube, an electron gun section that generates an electron beam, a high-frequency circuit section that converts the energy of the electron beam into high-frequency energy, a collector section that captures the electron beam, and a beam focusing device that focuses the electron beam. It is a component.

Ultra-high-power microwave tubes handle greater power than ordinary high-power microwave tubes, and the value ranges from several 1100K to several tens of MW (mega-wall) VC. Such ultra-high power microwave tubes include not only those operating in continuous waves but also those operating in pulses. In the case of pulse operation, there are cases of short pulses with a pulse width of several microseconds to several tens of seconds, long pulses with a pulse width of several seconds to several tens of seconds, and of course there are cases of pulse widths in between.

The present invention particularly relates to a collector 1C of a straight beam type superpower microwave tube of long pulse operation.

A conventional collector structure of this type of microwave tube is shown in FIG.

The huge amount of heat generated in the collector (e.g. several megawatts
In order to efficiently release the heat (several seconds) to the outside, it is common to use an evaporative cooling method as the cooling method. In FIG. 1, 1 is an electron beam entrance hole, and 2 is an electron beam. 3 indicates a collector core, which performs electron beam trapping and forms part of the vacuum vessel. A large number of radially formed heat sinks 4 are installed outside the collector core 3. The power loss in the collector is very large, several megawatts, and the shape of the collector in the case of long pulse operation is very large (for example, diameter 500 mm, height 1500 wm), making it difficult to process it in one piece. Therefore, the collector is usually divided into several parts and manufactured individually, and then used by joining (for example, soldering) the seven parts together. 1st
The figure shows an example in which the collector is divided into four parts in the axial direction.

Further, 5 indicates a jacket installed outside the collector, and the space between the collector core 3 and the jacket 50 is filled with distilled water 6. When the electron beam 2 enters, the kinetic energy of the electron beam is converted into thermal energy by the collector core 3, and the radiator converts water into steam through the heat sink 4, releasing the heat to the outside as vaporization heat. That's why. A cross-sectional view of the outermost portion of the collector shown in FIG. 1 is shown in FIG.

The following drawbacks have been found in the conventional structure of this type of long-pulse operation superpower microwave tube. In other words, after a relatively small number of beam applications have been applied, a vacuum rupture occurs from the junction of the collector core 3 (section a or b in Figure 1), causing the microwave tube to momentarily shut down. I made it inoperable and left it there.

The inventors investigated the causes of these accidents and found the following. That is, the temperature inside the collector core 3 reaches approximately 500° C. within a few seconds after the beam is applied. On the other hand, since the outside of the collector core 3 is in direct contact with water, its temperature is about 10θ to 130°C. Due to this temperature difference 1cJ5 between the inside and outside, the collector core 3 tends to be thermally deformed so that the inside of the core is warped. If the mechanical rigidity of the heat sink 4 is ignored, this thermal deformation will deform in accordance with the Sobeam input distribution, but in reality, the mechanical rigidity of the heat sink 4 was large, so the heat sink 4 It acts as a rib (reinforcing body) against thermal deformation of the collector core, and places where thermal deformation can occur are concentrated in areas where there is no heat dissipation body 4, in other words, at the joint between the collector and the core. FIG. 3 shows changes in the collector shape before and after thermal deformation in a conventional collector. The solid line shows the shape before thermal deformation, and the dotted line shows the shape after thermal deformation.

It can be seen that during thermal deformation, a tensile force acts on the outside of the collector core and a compressive force acts on the inside of the collector core at the joint (the part without a heat sink). If a pulse operation with an application time of 10 seconds and a beam application time of 10 seconds is performed, the above thermal deformation will be repeated every 160 seconds, causing fatigue in the metal and eventually causing cracks. The bulge progresses and eventually leads to vacuum breakage.

An object of the present invention is to provide a collector for a microwave tube having a structure that is much more durable than the conventional collector, for use as a collector for a long-pulse operation superpower microwave tube, based on the conclusion of the above-mentioned research.

When looking at the circumferential cross section of the heat sink, the heat sink is subdivided into smaller parts than before in the tube axis direction and in the direction perpendicular to the heat sink, thereby increasing the mechanical rigidity of the heat sink to 7fLK of the collector core. : This is a method that significantly weakens the strength compared to the previous one. An embodiment of the present invention is shown in FIG. 6, in comparison with FIG. 5 of the prior art, showing how the heat sinks are lined up on the surface of the collector core. In Figure 6, the circumferential dimension of each heat sink (a in the diagram) is the thickness of the collector core (t in the diagram).
The characteristic is that the vertical dimension (b in the figure) is approximately twice or less than t.

Next, differences between the present invention and the prior art will be explained. First of all, the conventional design policy for heat radiators was to focus mainly on securing heat dissipation characteristics, resulting in large rigidity of the heat radiator. They are fundamentally different in that they are designed with a focus on mitigation. For this reason, in the prior art, the above t and a.

There are no restrictions between b. In addition, most of the conventional microwave tubes have an output level of several IQkW, hp,
For this reason, the collector can be kept small, and the collector and core can be fabricated as one piece, which is rare. For this reason, there were almost no problems such as splitting the collector core or leakage from the brazed portion due to the collector core. Furthermore, in the case of long pulse operation, the aforementioned thermal fatigue problem arises.
In the prior art, no consideration was given to these problems. According to the present invention, it is possible to obtain a collector structure that is highly effective in solving these problems.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views showing the conventional collector structure, Figure 3 is a cross-sectional view showing the state of thermal deformation of the conventional collector, and Figure 4 is a cross-sectional view showing the conventional collector structure.
5 is a cross-sectional view showing a collector structure according to the present invention, FIG. 5 is an external view of a heat radiating body of a conventional collector, and FIG. 6 is an external view of a heat radiating body according to the present invention. 1...Electron beam entrance hole, 2...Electron beam, 3...Collector core, 4...
・Heat sink, 5... Jacket, 6...
Distilled water. Agent: Susumu Uchihara, patent attorney. , / Figure I Figure 22 Figure 3 Figure 4 Figure S Winding Figure G

Claims (1)

[Claims] In a straight-beam microwave tube composed of an electron gun section, a high-frequency circuit section, a collector section, a beam focusing device, etc., the collector is evaporatively cooled and the members constituting the collector are divided into a plurality of parts. The structure of each collector member is an annular or conical collector core, and a plurality of heat sinks arranged radially outside the collector core. Assuming that the dimension in the tube axis direction of the circumferential cross section of each heat radiator is a, the dimension in the direction perpendicular to the tube axis is a, and the thickness of the collector core is t, a≦pott, and b<z t A microwave tube characterized in that it has a dimensional ratio.