JP2679377B2 - Collector for electron beam tube - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam tube collector, and more particularly to an electron beam tube collector having an operating frequency in the millimeter wave band.

[Conventional technology]

The traveling wave tube collector consists of an electrode that captures the electron beam that has interacted with high frequencies in the slow wave circuit.When the electron beam hits the collector electrode, the kinetic energy of the electron beam is converted into thermal energy. It Therefore, the collector electrode is heated to a high temperature and gas is released from the metal forming the collector electrode.

By the way, in recent years, traveling wave tubes have come to be developed to operate in the millimeter wave band with a frequency of 30 GHz or higher, in line with the progress of higher frequencies and dust of progress in manufacturing technology.

In such a millimeter wave band traveling wave tube, the inner diameter of the helix that constitutes the slow wave circuit becomes as small as about 0.5 mm, and the electron beam passage hole diameter at the collector inlet also returns from the inside of the collector to the helix part according to this diameter. In order to suppress it, it is necessary to make it as small as the inner diameter of the helix.

On the other hand, as shown in FIG. 3, the collector structure is electrically insulated from the slow wave circuit unit 2 by an insulating stone 3, and the shape of the collector electrode 21 on the slow wave circuit unit 2 side is a conical shape. doing. Only one electron beam passage hole 4 through which the electron beam passes is formed at the apex of the conical partition wall, and the side surface and the bottom surface connected to the conical partition wall form a vacuum envelope.

[Problems to be solved by the invention]

In such a collector structure, the gas generated when the electron beam collides with the inner wall of the collector electrode and generates heat is passed through the electron beam passage hole through which the electron beam passes, for example, a getter provided on the electron gun side. Alternatively, it is absorbed by an ion pump (not shown) provided in the output section. However, in the millimeter wave band traveling wave tube, since the electron beam passage hole diameter at the tip of the partition wall of the collector electrode is small, the exhaust resistance to gas becomes large and the degree of vacuum inside the collector deteriorates. Therefore, there is a problem that ions are generated by the collision of the electron beam with the gas molecules, which causes adverse effects such as fluctuation of the helix current and accelerated deterioration of the cathode.

An object of the present invention is to provide an electron beam tube that does not cause any adverse effects such as fluctuations in helix current and accelerated deterioration of the cathode.

[Means for solving the problem]

The present invention includes a bottom surface and a side surface forming a vacuum envelope, and an electron beam passage hole connected to the side surface and on the central axis of the electron beam on the side of the slow wave circuit unit and housed in the vacuum envelope. In a collector for an electron beam tube having a partition, the partition has a plurality of exhaust holes.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 (a) and 1 (b) are a sectional view and a view taken along the line AA 'of a traveling wave tube collector according to a first embodiment of the present invention.

In the first embodiment, as shown in FIGS. 1A and 1B, the collector electrode 1 is electrically insulated by the slow wave circuit 2 and the insulating stone 3. The shape of the partition wall of the collector electrode 1 is
It has a conical shape, and an electron beam passage hole 4 through which an electron beam passes is opened at the apex of the conical partition wall. The hole diameter is slightly larger than the inner diameter of the helix 5.

Further, a plurality of exhaust holes 6 are opened in the conical partition wall, and has a role of exhausting gas generated in the collector electrode 1. The direction of the exhaust hole 6 is determined in consideration of the electron beam entering the collector electrode 1 from passing through the outside of the collector electrode 1 again. Further, the hole diameter D of the exhaust hole 6 is made smaller than the flow L of the exhaust hole 6 so that the electrons in the collector electrode 1 cannot easily pass through.

In addition, as a precaution, the collector electrode 1 should be prevented from flowing backward from the collector electrode 1 to the slow wave circuit 2 through the exhaust hole 6.
It is also conceivable to attach a component for seeding the exhaust hole 6 to the slow wave circuit side of the conical partition wall.

FIG. 2 is a sectional view of a collector for a traveling wave tube according to a second embodiment of the present invention.

In the second embodiment, as shown in FIG.
This is an example of the case where the tip shape of the partition wall of 11 does not have a conical shape.

That is, when the tip of the partition wall of the collector electrode 11 has a cylindrical shape, the same effect as that of the first embodiment can be obtained by providing the exhaust hole 6 on the cylindrical side surface.

In the present embodiment, the case where the number of stages of the collector electrode is one has been described, but even in the case of a multi-stage collector, it can be applied to the collector electrode closest to the slow wave circuit.

Further, the application of the present invention should not be limited to traveling wave tubes, but can be applied to various electron beam tubes such as klystrons.

〔The invention's effect〕

As described above, according to the present invention, since the plurality of exhaust holes are provided in the partition wall of the collector electrode, even if the electron beam passage hole diameter of the collector electrode is small like a traveling wave tube for the millimeter wave band, the collector electrode The gas generated in 1 is exhausted through the exhaust hole of this partition. Therefore, gas molecules are less likely to be ionized in the collector electrode due to collision of the electron beam, and defects such as fluctuation of the helix current and accelerated deterioration of the cathode are eliminated, and a highly reliable traveling wave tube can be obtained. effective.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are a sectional view and a sectional view taken along the line AA 'of the traveling wave tube collector of the first embodiment of the present invention, and FIG. 2 is a progression of the second embodiment of the present invention. FIG. 3 is a sectional view of a collector for a wave tube, and FIG. 3 is a sectional view of an example of a conventional collector for an electron beam tube. 1,11,21 …… Collector electrode, 2 …… Slow wave circuit, 3 …… Insulating stone, 4 …… Electron beam passage hole, 5 …… Helix, 6
...... Exhaust hole.

Claims (1)

(57) [Claims] 1. A vacuum envelope is provided with a bottom surface and a side surface, and an electron beam passage hole connected to the side surface and on the central axis of the electron beam on the side of the slow wave circuit section and housed in the vacuum envelope. An electron beam tube collector having a partition wall, wherein the partition wall is provided with a plurality of exhaust holes.