JPS6047694B2 - high power klystron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high power klystron using a permanent magnet as an electron beam focusing device, and more particularly to a high power klystron using a samarium cobalt magnet.

When a permanent magnet is used as a magnetic force source in a magnetic field device for focusing an electron beam, an alcony-based magnet has conventionally been generally used.

The air-cooled klystron in this case is shown in FIG. In the figure, 1 is an electron gun unit that emits an electron beam, 2 is a high frequency circuit unit where the interaction between the electron beam and an input high frequency wave takes place, 3 is a collector that collects the electron beam after the interaction, and 4 are cooling fins of the collector 3. A pair of cylindrical pole pieces, that is, a collector side pole piece 5a and an electron gun side pole piece 6, are provided at both upper and lower ends of the high frequency circuit section 2, and have an aperture in the center through which the electron beam passes. The side pole piece 6 forms a part of the container of the electron gun section 1, and the collector side pole piece 5a
is interposed between the collector 3 and the high-frequency circuit section 2, and the tip of the collector 3 on the high-frequency circuit section side is partially inserted into the cylindrical body of the pole piece 5a, and is connected to the pole piece 5a through the sealing insulator 7. It is fixed to the inner wall, and the end of the electron gun section 1 is also hermetically sealed to form a container-like klystron tube whose interior is evacuated. Furthermore, alnico permanent magnets Ba are attached to extend radially outward from the four sides of each of the collector side pole piece 5a and the electron gun side pole piece 6, and a pair of magnets facing each other in the tube axis direction is attached. A magnetic field for electron beam focusing along the axial direction is formed in the high frequency circuit section 2 by a magnetic circuit including a yoke 9 interposed between the outer magnetic pole surfaces.

10 is a duct, and a suction blower (not shown) provided above the duct generates a flow of cooling air as shown by an arrow 11, and the collector fins 4 are exposed to this wind, and the heat of the collector 3 is removed. Efficiently dissipated.

By the way, if you want to reduce the dimensions of the klystron,
A samarium cobalt magnet is used, which has a larger energy product than an alkoni magnet.

When using this samarium cobalt magnet, it is necessary to make the cross-sectional area relatively large due to the characteristics of the magnet. Therefore, it is necessary to increase the height of the magnet portion 8.
For this reason, the collector cooling fins 4 are placed higher than in the case of an alconi type magnet, but since the collision point of the beam edge is near point A, the effect of heat transfer from the heat generating part to the heat radiating part is worsened. However, the collector cooling effect is significantly worse than in the case of an alconi type magnet. At this time, the ball piece 5a does not need to be at the same height as the magnet 8, and may have a structure in which it is cut in the middle as shown in FIG.

Therefore, small fins 12 are further added to the high frequency circuit side of the collector 3 to cool the collector. However, in this structure, since the ball piece 5a is present, most of the cooling air flows through the small fins 12, as shown by the arrow 11.
The cooling effect of the small fins 12 is extremely poor.

The above are the drawbacks of using samarium cobalt magnets. SUMMARY OF THE INVENTION An object of the present invention is to provide a high-power klystron that eliminates the inconvenience of collector cooling caused by the use of samarium cobalt magnets.

FIG. 3 shows an embodiment of the present invention, and in the figure, there is a vertical penetration on the outer periphery of the collector side ball piece 5! Several holes 13 are provided, and air for cooling the small fins 12 flows from the bottom of the ball piece through the through holes 13 as shown by arrows 14.
The small fins 12 are cooled through. Through hole 13 is shown in Figure 4.
A perspective view shows a ball piece 5 with a groove for creating the groove.
FIG. 5 is a curve diagram showing the effect of the present invention, with the beam input (KW) on the horizontal axis and the temperature of the small fin collector section (°C) on the vertical axis.Curve 14 is shown in FIG. The characteristic before improvement, curve 15, is the characteristic of the klystron of the present invention, and in this example, the temperature of the small fin part, which was 160°C in the case of a beam input of 7kW, was lowered by 70°C to 90°C,
A very large improvement in the cooling effect was obtained and therefore a significant improvement in tube life was achieved.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the structure of an air-cooled klystron using a conventional alconi-based magnet, Fig. 2 is a cross-sectional view showing the structure of an air-cooled klystron using a samarium cobalt-based magnet, and Fig. 3 is a cross-sectional view showing the structure of an air-cooled klystron using a samarium cobalt magnet. FIG. 4 is a cross-sectional view showing the structure of an air-cooled klystron equipped with a ball piece having a through hole and using a samarium cobalt magnet. FIG. FIG. 5 is a characteristic curve diagram of beam input versus small fin collector temperature of the air-cooled klystron shown in FIGS. 2 and 3. In the figure, 1...electron gun section, 2...
...High frequency circuit section, 3...Collector, 4...
...Fin, 5... Collector side ball piece with a groove for forming a through hole, 5a... Collector side ball piece, 6... Electron gun side ball piece, 8.
...Samarium cobalt magnet, 9...Yoke, 12...Small fin, 13...Through hole on the outside of the ball piece.

Claims (1)

[Claims] 1. an electron gun unit that emits an electron beam; a high frequency circuit unit that interacts with the electron beam and input high frequency;
a collector that collects the electron beam after the interaction; a cylindrical pole piece on the collector side and the electron gun side that are arranged to face each other with the high frequency circuit portion interposed therebetween in the axial direction; A large magnet comprising a plurality of permanent magnets attached to extend radially outward from the outer surface, and a yoke extending between the outer magnetic pole tips of each pair of permanent magnets facing each other in the axial direction. In power microwave tubes,
The high-frequency circuit side tip of the collector is inserted into the cylindrical body of the collector side pole piece, and the collector part protruding from the cylindrical body has a small cooling fin, and the collector side pole piece and the permanent magnet are connected. A high-power klystron, characterized in that a vertical through hole is provided in the section for allowing the cooling air for cooling the small fins to pass through.