JPH04106840A - Collector for electron beam tube - Google Patents

Abstract

PURPOSE:To prevent occurance of troubles such as fluctuation of helix current and acceleration of cathode deterioration by forming a plurality of holes for gas discharge in a diaphragm of a collector electrode. CONSTITUTION:The shape of the diaphragm of a collector electrode 1 is conical and an electron beam passing hole 4 through which electron beam passes is opened at the summit of the conical diaphragm. A plurality of holes 6 for gas discharge are opened in the conical diaphragm and work for discharging a gas generated in the collector electrode 1. The direction of the holes 6 for gas discharge are so determined as to prevent the electron beam which enters in the inside of the collector electrode 1 from passing out of the collector electrode 1 again and the diameter D of a hole for gas discharge is smaller than the length L of a hole 6 for gas discharge, so that electrons in the collector electrode 1 hardly pass through. Consequently, ionization of gas molecules by collision of the electron beam against the gas molecules is lowered in the collector electrode 1. As a result, defects such as helix current fluctuation acceleration of cathode deterioration, etc., are eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a collector for an electron beam tube, and more particularly to a collector for an electron beam tube with an operating frequency in the millimeter wave band.

[Conventional technology]

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

Incidentally, in recent years, the frequency of traveling wave tubes has been increasing, and together with advances in manufacturing technology, traveling wave tubes that operate in a millimeter wave band with a frequency of 30 GHz or higher have been developed.

In such millimeter-wave band traveling wave tubes, the inner diameter of the helix constituting the slow-wave circuit is as small as about 0.5 mm, and the diameter of the electron beam passage hole at the collector entrance also changes from the inside of the collector back to the helix section, corresponding to this diameter. In order to suppress electrons, 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 structure of the collector is electrically insulated from the slow wave circuit section 2 by an insulating stone 3, and the collector electrode 21 on the slow wave circuit section 2 side has a conical shape. are doing. A single electron beam passage hole 4 through which the electron beam passes is opened at the apex of this conical partition, and the side and bottom surfaces connected to the conical partition form a vacuum envelope.

[Problem 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 passes through the electron beam passage hole through which the electron beam passes through, for example, to a getter provided on the electron gun side. , or an ion pump provided at the output section (none of which is shown). However, in millimeter-wave band traveling wave tubes, the diameter of the electron beam passing hole at the tip of the partition wall of the collector electrode is small, so the exhaust resistance to gas increases and the degree of vacuum inside the collector deteriorates. Therefore, there is a problem in that ions are generated when the electron beam collides with gas molecules, causing problems such as fluctuations in the helix current and accelerated deterioration of the cathode.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam tube that does not cause problems such as fluctuations in helix current and accelerated deterioration of the cathode.

[Means for Solving the Problems] The present invention provides a bottom surface and a side surface forming a vacuum envelope, and an electron beam passing hole connected to the side surface and located on the central axis of the electron beam on the slow wave circuit side. In the electron beam tube collector having a partition wall housed in a vacuum envelope, the partition wall is provided with a plurality of exhaust holes.

〔Example〕

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

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

In the first embodiment, as shown in FIG. 1<a) and (b),
Collector electrode 1 is electrically insulated by slow wave circuit 2 and insulating stone 3. The partition wall of the collector electrode 1 has a conical shape, and an electron beam passage hole 4 through which the electron beam passes is opened at the apex of the conical partition wall. The diameter of this hole is slightly larger than the inner diameter of the hesock 5.

Furthermore, a plurality of exhaust holes 6 are opened in the conical partition wall, and have the role of exhausting gas generated within the collector electrode 1. The direction of the exhaust hole 6 is determined with consideration given to preventing the electron beam that has entered the collector electrode 1 from passing through to the outside of the collector electrode 1 again. Further, the diameter of the exhaust hole 6 is made smaller than the flow length L of the exhaust hole 6 to prevent electrons in the collector electrode 1 from easily passing through.

As a precaution, a part that shields the exhaust hole 6 is attached to the slow wave circuit side of the conical partition wall of the collector electrode 1 to prevent electrons from going backward from the collector electrode 1 to the slow wave port R2 through the exhaust hole 6. Structure can also be considered.

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

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

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

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

Further, the application of the present invention is not limited to traveling wave tubes, but can be applied to various types of electron beam tubes including klystrons.

〔Effect of the invention〕

As explained above, in the present invention, since a plurality of exhaust holes are provided in the partition wall of the collector electrode, even when the electron beam passing hole diameter of the collector electrode is small as in a millimeter wave band traveling wave tube, the collector electrode The gas generated is exhausted through the exhaust holes in this partition wall. Therefore, gas molecules in the collector electrode are less likely to be ionized by electron beam collisions, eliminating drawbacks such as fluctuations in helix current and accelerated cathode deterioration, resulting in a highly reliable traveling wave tube. effective.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a cross-sectional view and a view taken along the line A-A' of a collector for a traveling wave tube according to a first embodiment of the present invention, and FIG. 2 is a progress view of a collector for a traveling wave tube according to a second embodiment of the present invention. 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.・
・Hewax, 6...Exhaust hole.

Claims (1)

[Claims] It has a bottom surface and a side surface forming a vacuum envelope, and a partition wall connected to the side surface and having an electron beam passing hole on the central axis of the electron beam on the slow wave circuit side and housed in the vacuum envelope. What is claimed is: 1. A collector for an electron beam tube, characterized in that the partition wall is provided with a plurality of exhaust holes.