JPS6158937B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a multistage collector type electron beam tube in which the collector is configured in multiple stages in order to improve efficiency, among electron beam tubes having a collector that ultimately captures an electron beam that has contributed to an amplification effect. In an electron beam tube such as a traveling wave tube, an electron beam emitted from an electron gun undergoes high frequency amplification in a high frequency circuit section and is then captured by a collector. At this time, the efficiency of the electron beam tube increases if the electron beam reaches the collector in a state in which the energy of collision with the collector is reduced.
In order to improve efficiency, a method has generally been used in which the collector voltage is lowered than the high frequency circuit voltage. However, since there are variations in the speed of the electron beams involved in the high-frequency amplification effect, in order to capture electron beams with these variations in speed with a single collector, it is necessary to apply a voltage that allows the slowest electrons to reach the collector. collector voltage, making it difficult to significantly improve efficiency. For this reason, various electron beam tubes in which the collector is divided into a plurality of pieces have been considered in order to further improve efficiency.
It is true that if the number of collector divisions is increased and voltages that are sequentially lower than the high-frequency circuit voltage are applied to each collector individually as the distance from the high-frequency circuit increases, the electron beams involved in the high-frequency amplification effect will be speed-sorted by the collector. be captured. That is, a slow electron beam is captured by a collector with a high potential, and a fast electron beam is captured by a collector with a low potential, improving efficiency. However, in order to divide the collector into multiple pieces, it is necessary to electrically insulate each collector, and in order to cool each collector, a heat sink is installed on the outer periphery of each collector, which is electrically insulated from the ground point. It was necessary to attach the collector part, which complicated the structure of the collector part, and there were drawbacks such as an increase in the size and weight of the collector part including the heat sink. Furthermore, in order to cool the individual collectors, it is difficult to provide sufficient electrical insulation between the collectors or between each collector and the ground point. In particular, when the collector is divided into three or more stages, the above-mentioned drawbacks become noticeable. The present invention has a collector divided into a plurality of pieces,
In an electron beam tube in which multiple collectors are electrically insulated from the ground point, sufficient cooling effect is obtained by effectively transmitting the heat generated in the collectors to the outside with a simple structure. In addition, it is an object of the present invention to provide a multi-stage collector type electron beam tube in which the collector can be easily insulated from the ground point. According to the present invention, an electron gun that generates an electron beam, a high frequency circuit section in which high frequency interaction is performed, a magnetic field focusing device for focusing the electron beam, and a plurality of collectors that are at a lower potential than the high frequency circuit section. In an electron beam tube equipped with A multi-stage collector type electron beam tube with collector cooling is obtained. Next, the present invention will be explained in detail with reference to the drawings. FIG. 1 shows a traveling wave tube embodying the present invention, and this traveling wave tube includes an electron gun 1,
High frequency circuit section (slow wave circuit) 2, high frequency input section 3,
High frequency output section 4, magnetic field focusing device 5, collector 11
and a heat radiator 13, etc., and a support plate 14 on the electron gun side and a holding plate 6 on the collector side via a support plate 15.
It is placed and fixed on top. Thus, the collector 11 includes the first collector 7, the second collector 8, and the third collector 7.
It is divided into a collector 9 and a fourth collector 10 in the axial direction, and these are electrically insulated via a cylindrical insulating stone 17. Further, the first collector 7 and the high frequency circuit section 2 are electrically insulated via a cylindrical insulating stone 12. The material used for the collector is copper, molybdenum, or nickel, which has good thermal conductivity and a high melting point temperature, and the cylindrical insulating stone 17 is made of beryllia ceramic, which is dense and has good thermal conductivity among insulating stones. or alumina ceramic, both end surfaces of the cylindrical insulating stone 17 are metallized and bonded to the first to fourth collectors by brazing. In such an electron beam tube, the electron beam emitted from the electron gun 1 is focused by the magnetic field focusing device 5 and passes through the central axis of the high frequency circuit section 2, during which time it is combined with the high frequency applied from the high frequency input section 3. An amplification effect is performed by the interaction, and high frequency output is extracted from the high frequency output section 4. However, since there are variations in the speed of the electron beam that has undergone high-frequency amplification, the electron beam is transferred to the first to fourth collectors 7, 7,
Captured on either 8, 9, or 10. In this case, the heat generated in the first to third collectors 7, 8, and 9 is transferred to the fourth collector 10 using the cylindrical insulating stone 17 as a heat conduction path, and a heat dissipation body disposed on the outer periphery of the fourth collector 10 is used. 13 to the holding plate 6 at ground potential via an electrically insulating plate 16 to cool the first to fourth collectors 7, 8, 9, and 10. The insulating plate 16 is made of a beryllia ceramic plate or the like with good heat conduction, and includes the heat sink 13, the insulating plate 16, and the support base 1.
The space between 5 and 5 is fixed with adhesive such as soldering. With such a structure, the heat generated in the first to third collectors 7, 8, and 9 is transferred to the fourth collector with the heat sink 13.
It is sufficiently conducted to the collector 10, and furthermore, the heat sink 13
Since the heat is quickly radiated to the holding plate that forms the heat flow field, there is no need to directly attach a heat radiator to each of the first to third collectors 7, 8, and 9 for cooling, and the number of divided collectors is independent. Therefore, only one heat conduction path to the heat sink leading to the heat flow field is required, which simplifies the structure of the collector part and is extremely advantageous in reducing the size and weight of the collector part. Further, the collector can be sufficiently insulated from the ground point by the cylindrical insulating stone 17 and the insulating plate 16. The thermal resistance between each collector is determined by the thermal conductivity and dimensions of the cylindrical insulating stone 17, and the dimensions of the cylindrical insulating stone 17 are selected in consideration of the power consumed by each collector and the temperature allowed for the collector. Insulating stone 17
can fully fulfill its role as a heat conduction path. Next, specific numerical examples in the embodiment shown in FIG. 1 will be shown. The heat between each collector when the first to fourth collectors 7, 8, 9, and 10 are made of copper plates with a thickness of 1 mm, and the dimensions of the cylindrical insulating stone 17 are 50 mm in outer diameter x 40 mm in inner diameter x 5 mm in length. Since the thermal resistance of the collector is small, the resistance R _T is approximately equal to the thermal resistance of the cylindrical insulating stone 17.
It is expressed as _T =/λ×S(°C/W). Here, λ and S are the thermal conductivity, cross-sectional area, and length of the cylindrical insulating stone 17, respectively, and λ is approximately 1.25W/℃×cm
(Beryllium ceramic) approximately 0.2W/℃×cm (Alumina ceramic). When the above values are substituted into the formula for R _T , R _T becomes 0.6°C/W (in the case of beryllia ceramic) and 3.5°C/W (in the case of alumina ceramic). When the temperature rise of each collector when 10 W of power is consumed in each collector is determined by assuming that the temperature of the fourth collector 10 where the heat sink 13 is disposed is T ₄ °C, the results shown in Table 1 are obtained.

[Table] As is clear from Table 1, the first collector 7 has the highest temperature among the first to fourth collectors 7, 8, 9, and 10, but the fourth collector 10 has the highest temperature.
The temperature T ₄ of the first collector 7 can be easily cooled down to 100°C or less by the heat sink 13, so even if alumina ceramic is used as the material for the cylindrical insulating stone 17, the temperature of the first collector 7 will be around 300°C at most. Therefore, considering the permissible collector temperature (400 to 600°C), it can be put to practical use. Furthermore, if the material of the cylindrical insulating stone 17 is beryllium ceramic, the temperature of the first collector can be kept below 300°C even if 50W of power consumption is given to each collector, and the high-power electron beam It becomes possible to manufacture pipes. Furthermore, if the inner and outer diameters of the cylindrical insulating stone 17 are wave-shaped, the electrical insulation between the collectors can be further improved without changing the thermal resistance between the collectors. 2 and 3 show axial cross-sectional views of the collector portion of another embodiment of the electron beam tube according to the present invention,
The same or corresponding parts as in FIG. 1 are given the same numbers. In FIG. 2, the heat generated in the second to fourth collectors 8, 9, and 10 is transferred to the first collector 7 using the cylindrical insulating stone 17 as a heat conduction path.
A heat radiator 13 is disposed around the externally extending metal body of the collector 7 and communicates with the ground holding plate 6 at the shortest distance.
According to the embodiment shown in FIG. 2, cooling of the first and second collectors 7 and 8 becomes easier compared to the embodiment shown in FIG. Therefore, it is suitable for an electron beam tube in which the first and second collectors 7 and 8 consume a large amount of power. In FIG. 3, the second to fourth collectors 8,
9 and 10 is transferred to the first collector using the cylindrical insulating stone 17 as a heat conduction path.
The heat collected in the collector is transmitted together with the heat generated in the first collector 7 to the end 18 of the high frequency circuit section via the cylindrical insulating stone 12, and the vacuum container extends around the outer periphery of the end of the high frequency circuit section. A heat dissipating body 20 with heat dissipating blades is disposed in the outer circumferential cylinder 19 which becomes a part of the first to
The fourth collectors 7, 8, 9, and 10 are cooled.
The cylindrical insulating stone 12 is made of beryllia ceramic or alumina ceramic, the same as the material of the cylindrical insulating stone 17. A high-voltage lead wire (not shown) is provided on the ceramic 22 fixed to the end of the outer cylinder 19 by brazing or the like, and the first to fourth collectors 7, 8, 9, and 10 are connected via the lead wire. Voltage is supplied. According to the embodiment shown in FIG. 3, compared to the embodiment shown in FIG. 1, the outer circumferential cylinder 19 that fits into the heat sink 20 serves as a grounding point, so the heat sink 20 is different from that shown in FIGS. 1 and 2. Unlike the heat radiator 13, it is not necessary to arrange the heat radiator blades on an electrically insulating plate, and the heat radiator blades can be directly attached to the heat radiator 20. Further, since the outer cylinder 19 constitutes a part of the vacuum container, the first to fourth collectors 7,
8, 9, 10 and the cylindrical insulating stones 12, 17 do not necessarily need to be adhesively fixed by brazing or the like for vacuum sealing, but can also be fixed with screws, etc. 12 and 17 are not cylindrical ones that are approximately equal to the outer diameters of the first to fourth collectors 7, 8, 9, and 10, but are rod-shaped ones that have outer diameters that are a fraction of the outer diameters, It is also possible to arrange a plurality of them between each collector along the outer circumference of the collector. In the embodiment shown in FIG. 3, electrical insulation with respect to the ground point of the collector is mainly determined by the dimensions of the cylindrical insulating stone 12, but if the inner and outer diameters of the cylindrical insulating stone 12 are made waveform instead of straight. , since the distance between the first collector and the high frequency circuit end 18 is substantially longer, it is possible to improve the electrical isolation of the collector with respect to the ground point. Furthermore, if 21 insulating rings shown by dotted lines are inserted between the fourth collector 10 and the circumferential cylinder 19, mechanical reinforcement and heat conduction will be improved. Although in the above embodiment, a coaxially coupled traveling wave tube with a collector divided into four stages is used as the electron beam tube, the present invention is not limited to this, and the collector can be divided into two or more stages. Of course, it can be applied to an electron beam tube such as a waveguide-coupled klystron that is divided into two. According to the present invention, regardless of the number of collector divisions, heat generated in the collector is effectively transmitted to the outside without deteriorating the electrical insulation between each collector and the electrical insulation between each collector and a ground point. Even if the collector is divided for the purpose of improving efficiency, it is possible to prevent the collector portion from increasing in size and drooping amount. In particular, great effects can be obtained when the present invention is applied to an electron beam tube in which the collector is divided into three to five stages or more.

[Brief explanation of the drawing]

FIG. 1 is an axial sectional view showing one embodiment of the multi-stage collector type electron beam tube according to the present invention, and FIGS. 2 and 3 show the collector section of another embodiment of the multi-stage collector type electron beam tube according to the present invention. FIG. 3 is an axial cross-sectional view. In the figure, 1 is an electron gun, 2 is a high-frequency circuit section, 5 is a magnetic field focusing device, 6 is a holding plate, 7, 8,
9 and 10 are first, second, third, and fourth collectors, respectively; 11 is a collector including the first to fourth collectors; 12 is a cylindrical insulating stone; 13 is a heat sink; 16 is an insulating plate; 17 is a A cylindrical insulating stone, 18 an end of a high frequency circuit, 19 an outer cylinder, 20 a heat radiator with heat radiating vanes, and 21 an insulating ring.

Claims (1)

[Claims] 1.Equipped with an electron gun that generates an electron beam, a high-frequency circuit unit that performs high-frequency interaction, a magnetic field focusing device that focuses the electron beam, and a collector that captures the electron beam that has undergone the interaction, and In a multi-stage collector type electron beam tube consisting of a plurality of collectors insulated from one end of the high frequency circuit section through a plurality of insulating stones, the collector is located at one end of the high frequency circuit section or of the plurality of collectors. A metal cylindrical body extending in the axial direction is provided at the outer end of one of the collectors, and a heat dissipation body is closely attached to the outer periphery of this metal cylindrical body, so that the heat generated in the collector is transferred to the insulating stone and the metal cylindrical body. A multi-stage collector type electron beam tube characterized in that the electron beam tube conducts heat to a heat dissipation body through a metal cylindrical body and dissipates the heat.