JPS5819841A - Travelling-wave tube - Google Patents

Abstract

PURPOSE:To make it possible to keep excellent concentricity of a tublar enclosure with a periodical permanent magnet by inserting a thin metal plate into a united part composed of the tublar enclosure forming a vacuum vessel surrounding a retardation circuit and periodical permanent magnet. CONSTITUTION:The microwaves amplifying portion of a helical travelling-wave tube is constitutd by a tublar enclosure 3 forming vacuum vessel surrounding a helix 1 and a helix supporting rod 2. Moreover, a magnet 4 and a pole piece 5 constituting a periodical permanent magnet around the enclosue are provided. A non-magnetic thin metal plate 6 is inserted into a gap between the enclosure 3 and the pole piece 5 depending on the size of said gap in order to provide the good concentricity of the helix with the pole piece 5. Hereby, it is possible to keep excellent electron beam transmission coefficient of a travelling-wave tube.

Description

Detailed Description of the Invention The present invention uses a periodic permanent magnet (P,
This paper relates to a PPMO positioning structure for a circular traveling wave tube using P, M).

A traveling wave tube consists of an electron gun that emits an electron beam, a collector that emits an electron beam, and a continuous interaction with the electron beam.
A microwave amplification section that amplifies the channel liquid, an input coupling section that makes the first channel wave enter a part of the microwave layer without loss, and a microphone W.
It consists of an output coupling part for direct waves from the liquid amplifier to reach the load wc@ without loss, and a focusing device (PPM) that provides an O1l field to focus the electron beam.Hiro and helix are installed in the microphone Tanami amplifier part of the traveling wave tube. shape, coupled cavity type, etc.), and are used depending on the purpose, but in ζζ, the herritus type traveling wave tube is used differently.

The helix-shaped traveling wave tube O miter is assembled from the helical tube, helix support rod, and tubular envelope.
IIiK, periodic permanent magnets (P, P, M) are provided to focus the electron beam passing through the interior of the helix. The structure of the helix type traveling wave tube high frequency circuit is simple and
Because its outer diameter is relatively small, PPM can be used as an electron beam focusing device and can be miniaturized, but it has the disadvantage that the helix itself is vulnerable to heat. Second, unless the transmittance of the electron beam is improved, stable operation of the traveling wave tube cannot be maintained. The following factors can be considered to reduce the electron beam transmittance in a PPM focusing helical traveling wave tube.

Second, the outer diameter of the microwave amplifying section is small and its overall length is long, so it is easy to move the microwave in one direction, and thirdly, the amplifying section is If the fitting between the surrounding tubular envelope and the PPM is not good, the concentricity will deteriorate and the electron beam transmittance will decrease.

For this reason, it is essential to adjust the transmission of the electron beam using a PPM focusing helix-shaped advancement tube. In particular, if the fit between the tubular envelope and the PPM is not good, even if the electron beam transmission has been adjusted, even if the tube is made of nine traveling wave tubes, small impactor vibrations during transportation or mounting may cause damage to the tubular envelope. On the other hand, when the PPM moves and the concentricity changes, the electron beam transmission characteristics deteriorate, causing a significant decrease in the reliability of the traveling wave tube.

The present invention provides a traveling wave tube in which concentricity between a PPM and a tubular envelope surrounding a microwave amplifying section and forming a vacuum container is maintained well.

The present invention uses a periodic permanent magnet as an electron beam focusing device, and uses a thin metal in the gold part of the periodic permanent magnet and the tubular external I8 device that surrounds all channels and forms a vacuum vessel by using a periodic permanent magnet. It is characterized by inserting a board.

The first wJK shows a commonly used microwave amplification section of a helical traveling wave tube. In the irises 111, - a helix 1 for propagating road waves, a helix support rod 2 for supporting the helix 1, and a tubular envelope 3 surrounding the helix 1 and the helix support rod 2 to form a vacuum container. The microphone-to-wadashi part of the helical traveling wave tube is constructed.

Further, a magnet 4 and a pole piece S forming the PPM are arranged around the tubular envelope.

Microwave amplification part and PPMOM centering are pole piece 5
and the tubular envelope 30.

In manufacturing, the inner diameter of the pole piece 5 and the outer diameter of the tubular envelope 3 are a combination of 3/100 to 5/1010 Os degrees, considering the difference in heat difference between the envelope and the pole piece O during baking and exhaust. Furthermore, the difference between the inner diameter of the pole piece 5 and the outer diameter of the tubular envelope 3 is 27,100 mm each.
Degrees are a must! ! It's coming.

Eventually, the gap between the diameter of the pole piece 5 and the tubular envelope 30 reached a maximum of α09m@j[,
The zero concentricity of the magnetic field between the helix 1 and the PPM deteriorates, and the electron beam transmittance becomes a problem when increasing the frequency and output of the traveling wave tube.

Furthermore, even with a traveling wave tube in which electron beam transmission adjustment has been completed, there is a possibility that the pole piece 5 of the PPM will move in a direction perpendicular to the tube axis with respect to the herritus 1 due to equilibrium vibration.
If the pole piece 5 moves, the electron beam transmission characteristics will deteriorate.

Next, the present invention will be explained using FIG. 2.

In Fig. 2, the concentricity of the helix l and the pole piece 5 is improved by inserting a non-magnetic thin metal plate between the tubular envelope 3 and the pole piece 5 according to the size of the gap. Furthermore, the electron beam transmittance of the helix-shaped traveling wave tube can be maintained at a good level even under vibrations and vibrations without deteriorating the concentricity.

If the present invention is adopted, the concentricity between the helix and the PPMli field can be maintained sufficiently well, so that the electron beam transmission characteristics can be maintained well even when the frequency of the traveling wave tube is increased. The stability of the traveling wave tube can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a microwave amplifying section of a conventional helical traveling wave tube, and FIG. 2 is a longitudinal cross-sectional view of a microwave amplifying section of a helical traveling wave tube according to the present invention. It is. 1...Helix, 2...Helix support rod, 3...Tubular outer device, 4...Magnet, 5...Pole piece , 6...metal plate.

Claims (1)

[Claims] As an electron beam focusing device, in a traveling wave tube using a periodic permanent magnet, a thin metal plate is inserted into the metal part of the periodic permanent magnet and the tubular outer tube that surrounds the slow wave path and forms a vacuum vessel. A traveling wave tube characterized by