JPH04359839A - Microwave tube - Google Patents

Abstract

PURPOSE:To eliminate use of any ion pump by adsorbing the gas released into a collector, while the bulb is in operation, automatically to a getter film which is produced through sputters of Ti or Ta. CONSTITUTION:The collector part has at least two collector electrodes 3, 6, wherein the same potential as the cathode is impressed on one of them, and part of the electrode is configured with a component 5 consisting of Ti or Ta.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a microwave tube.
In particular, it relates to the structure of its collector section.

0002

2. Description of the Related Art A conventional microwave tube, for example a single collector type traveling wave tube, has a collector section structure as shown in FIG. 3. The collector electrode 18, which also serves as a vacuum envelope, is made of copper and is electrically insulated from the slow wave circuit section 1 by an insulating stone 2 made of alumina ceramics. A bulk getter pump or ion pump 19 is mounted on an enclosure plate 20 which has the same potential as the slow wave circuit section 1 and is made of cover.

Next, the operation will be explained. The electron beam 7 that has contributed to the amplification collides with the inner wall of the collector electrode 18,
The temperature of the collector electrode 18 is increased. As a result, gas molecules adsorbed on the inner wall surface of the collector electrode 18 or gas molecules absorbed inside the copper constituting the collector electrode 18 are released over time. The gas molecules released into the collector are initially electrically neutral gas molecules 9
However, it collides with the electron beam 7 and changes into positive ions 10.

[0004] Normally, the collector potential is set to be 40 to 60% lower than that of the slow-wave circuit side, so the potential barrier generated between the collector electrode 18 and the slow-wave circuit section 1 Therefore, the positive ions 10 are confined inside the collector electrode 18, but as the gas release progresses, the amount of positive ions increases and the pressure increases, the positive ions 10 flow out into the slow wave circuit section 1 over the potential barrier. This may cause unstable operation such as ion noise and poor beam transmission. Therefore, in the conventional microwave tube, a bulk getter pump or an ion pump 19 is used for evacuation in order to remove the positive ions 10 that have flowed into the slow wave circuit section 1 and prevent unstable operation of the tube.

[0005]

[Problems to be Solved by the Invention] In this conventional collector structure of a microwave tube, since the bulk getter pump or ion pump protrudes from the tube, the outer diameter of the entire tube becomes large. In addition, it is necessary to periodically operate the pump for the tube in use, for example once a year, to exhaust the positive ions of the gas released from the collector.
Moreover, since it is not an easy task for anyone to perform, there is a problem in that it is very troublesome for users to manage and handle.

[0006]

[Means for Solving the Problems] The microwave tube of the present invention has a collector portion having at least two or more collector electrodes, one of which is applied with the same potential as the cathode,
Moreover, the electrode is characterized in that the entire or part of the electrode is made of titanium or tantalum.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view of a traveling wave tube according to a first embodiment of the present invention. The second collector electrode 6 is made of copper and also serves as a vacuum envelope. An electrode component 5 made of titanium or tantalum is joined to the second collector electrode 6 by brazing or welding. The second collector electrode 6 is electrically insulated from the first collector electrode 3 made of copper by an insulating stone 4 made of alumina ceramics. A cathode potential is applied to the second collector electrode 6. Taking the cathode potential as a reference, for example, the slow wave circuit section 1 has a voltage of 10 KV, and the first collector electrode 3
The voltage distribution is 5 KV, and the voltage distribution between the second collector electrode 6 and the electrode component 5 is OV.

The electron beam 7 that has contributed to the amplification does not collide with the electrode component 5 of the OV, but collides with the first collector electrode 3 having a high potential. The positive ions 10 of the emitted gas generated as a result of the temperature rise of the first collector electrode 3 are captured by impinging on the electrode part 5 of the OV. At this time, titanium or tantalum is sputtered by the impact of the collision, forming a getter film 8 on the inner wall of the first collector electrode 3, and adsorbing electrically neutral gas molecules 9 by the getter action. In this way, the emitted gas is exhausted while the tube is in operation, so that unstable operation of the tube caused by the emitted gas can be prevented.

FIG. 2 is a sectional view showing a second embodiment of the present invention. First collector electrode 12 and second collector electrode 1
4 is made of graphite and is brazed to insulating stones 11 and 13 made of alumina ceramics, respectively, and each insulating stone is further brazed to a vacuum envelope 15 made of Kovar. The third collector electrode 17 is made of titanium or tantalum, and is brazed to an insulating stone 16 made of alumina ceramics that also serves as a vacuum envelope.

Based on the cathode potential, for example, the slow wave circuit section 1 has a voltage of 10KV, the first collector electrode 12 has a voltage of 5KV, the second collector electrode 14 has a voltage of 2KV, and the third collector electrode has a voltage of 0V.
This is the voltage distribution. first collector electrode 12,
Gas molecules emitted from the second collector electrode 14 collide with the electron beam 7 and become positive ions 10, which are collided and captured by the third collector electrode 17 at 0V. At this time, the sputtered titanium or tantalum getter film 8 adsorbs electrically neutral gas molecules 9 by getter action. In this way, the released gas is exhausted in the same manner as in the first embodiment shown in FIG.

[0011] The above explanation has been made using a traveling wave tube as an example, but it is also effective for klystrons and the like.

0012

Effects of the Invention As explained above, the present invention applies a cathode potential to one of a plurality of collector electrodes, and furthermore, by forming the whole or a part of the one electrode from titanium or tantalum. , the released gas in the collector can be automatically evacuated during operation of the tube. As a result, it is possible to prevent unstable operation such as ion noise and poor beam transmission due to the outflow of ionized emitted gas to the slow wave circuit side, and there is no need to install an ion pump or bulk getter pump as required in the past. Therefore, the tube has advantages in terms of miniaturization and ease of handling.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a collector portion of a traveling wave tube according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a collector portion of a second embodiment of the present invention.

FIG. 3 is a sectional view of a collector portion of a traveling wave tube showing a conventional example.

[Explanation of symbols]

1 Slow wave circuit section 2, 4, 11, 13, 16 Insulating stone 3, 12
First collector electrode 5 Electrode parts 6, 14 Second collector electrode 7 Electron beam 8 Getter film 9 Electrically neutral gas molecules 10 Positive ions 15 Vacuum envelope 17 Third collector electrode 18 Collector electrode 19 Bulk getter pump or ion pump 2
0 Enclosure dish

Claims (1)

[Claims] Claim 1: An electron gun section that takes out an electron beam, an interaction section that amplifies and oscillates microwaves, a collector section that captures the electron beam that has contributed to the amplification and oscillation, and a magnetic focusing device that focuses the electron beam. In the microwave tube, the collector section has at least two or more collector electrodes, one of which has the same potential as the cathode, and the whole or part of the electrode is made of titanium or tantalum. A microwave tube characterized in that it is composed of parts.