Open type absorption cavity for TM220 higher-order mode klystron and preparation method and application of open type absorption cavity

Abstract

The invention provides an open type absorption cavity for a TM220 higher-order mode klystron and a preparation method and application of the open type absorption cavity. The open type absorption cavity is arranged in a magnetic field distribution area of a TM120 mode and a TM210 mode in an output cavity of a high-order mode klystron, and comprises a frame structure and an attenuation material body filled in the frame structure, the frame structure comprises an upper base, a lower base and a plurality of connecting pieces, the upper base and the lower base are arranged in parallel, the connecting pieces are vertically connected between a plurality of pairs of aligned corners of the upper base and the lower base respectively, a cavity structure with an open side face is defined by the upper base, the lower base and the connecting pieces, and the cavity structure is filled with the attenuation material body; the outer side faces of the attenuation material body and the peripheral face of the connecting piece are arranged in a coplanar mode, the open state of the four outer side faces of the attenuation material body is kept through the frame structure, the open outer side faces make direct contact with and are coupled with a magnetic field generated in an output cavity of the high-order mode klystron, and suppression and absorption of a TM120 mode and a TM210 mode are achieved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the technical field of microwave vacuum electron devices, and in particular to an open-type absorption cavity for TM 220 High-order mode klystron and preparation method and application of open-type absorption cavity thereof. BACKGROUND

[0002] The high-order mode klystron can be equivalent to multiple base mode klystrons working in parallel, which can significantly improve the resonant cavity power capacity and microwave power output, and reduce the cathode load by using multiple groups of cathode thermal sub-assemblies, thereby meeting the development needs of radar high power and high frequency band.

[0003] However, since the high-order mode klystron works in the high-order mode of the resonant cavity, there are many low-order modes at the low end of the frequency band that can easily cause oscillation, which seriously affects the pass rate, spectral quality and working stability of the klystron. Therefore, developing a high-performance absorption cavity to achieve mode suppression has become one of the research focuses. However, the number of modes to be suppressed by the high-order mode absorption cavity is large, and the electromagnetic field characteristics of each mode are significantly different, so the existing absorption cavity technology cannot meet the needs of high-order mode klystron for efficient suppression of mode oscillation. SUMMARY

[0004] Therefore, in order to at least partially solve the above-mentioned and other technical problems, embodiments of the present disclosure provide an open-type absorption cavity for TM 220 High-order mode klystron and preparation method and application of open-type absorption cavity thereof can realize effective suppression and absorption of TM 220 High-order mode klystron output cavity TM 120 Mode and TM 210 Mode.

[0005] In one aspect of the present disclosure, an open-type absorption cavity for high-order mode klystron is provided, which is arranged in the common distribution area of TM 120 Mode and TM 210 Mode magnetic field in the high-order mode klystron output cavity, the open-type absorption cavity includes a frame structure and a decay material body filled in the frame structure, wherein the frame structure includes an upper base, a lower base arranged in parallel, and a plurality of connecting pieces vertically connected between a plurality of pairs of aligned corners of the upper base and the lower base, respectively. The upper base, the lower base and the connecting pieces form a cavity structure with an open side, and the decay material body is filled in the cavity structure.

[0006] The outer side surfaces of the decay material body are respectively arranged in the same plane as the outer peripheral surfaces of the connecting pieces, and the open state of the four outer side surfaces of the decay material body is maintained by the frame structure, so that the open outer side surfaces are directly contacted and coupled with the magnetic field generated in the high-order mode klystron output cavity, thereby realizing suppression and absorption of TM 120 Mode and TM 210 Mode.

[0007] In another aspect of the present disclosure, a preparation method of the open absorption cavity is provided, comprising:

[0008] providing a mold matched with the frame structure, and placing the frame structure in the mold;

[0009] casting the semi-liquid attenuation material into the mold, so that the attenuation material fills into the cavity structure of the frame structure, semi-curing the attenuation material at a semi-curing temperature, and demolding the frame structure filled with the semi-cured attenuation material from the mold;

[0010] heating the demolded frame structure filled with the semi-cured attenuation material to a sintering temperature in a hydrogen furnace, so that the attenuation material is completely cured and connected with the frame structure, and obtaining the open absorption cavity after cooling.

[0011] In still another aspect of the present disclosure, an application of the open absorption cavity is provided, comprising: arranging the open absorption cavity at a center position of an output cavity of a TM 220 high-order mode klystron, to realize suppression and absorption of TM 220 modes in the TM 120 mode klystron, wherein the center position is a magnetic field concentrated distribution region of TM 210 modes and TM 120 modes. 210

[0012] According to the embodiments of the present disclosure, the frame structure of the open absorption cavity forms an open cavity, which provides mechanical support for the attenuation material body filled in the frame structure, disperses stress, and effectively avoids fragmentation or falling of the attenuation material body due to stress concentration; at the same time, the open cavity can directly expose the outer side of the attenuation material body, increase the contact area of the magnetic field of the attenuation material body with TM 120 modes and TM 210 modes to be suppressed in the output cavity, and improve the coupling efficiency, so as to realize effective suppression of non-working mode oscillation and guarantee the working stability and frequency spectrum quality of the TM 220 high-order mode klystron. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 a perspective view of the open absorption cavity provided by the embodiments of the present disclosure;

[0014] Figure 2 a perspective view of the frame structure of the open absorption cavity of the embodiments of the present disclosure;

[0015] Figure 3a a sectional view of the open absorption cavity made by using the mold according to the embodiments of the present disclosure;

[0016] ​Figure 3b A schematic view of a mold cross section for embodiments of the present disclosure;

[0017] Figure 4a A schematic view of a TM for embodiments of the present disclosure 220 A top view of an output cavity of a high-order mode klystron;

[0018] Figure 4b A schematic view of a TM for embodiments of the present disclosure 220 A cross-sectional view of an output cavity of a high-order mode klystron along line M-M;

[0019] Figure 5a A schematic view of a TM for embodiments of the present disclosure 220 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron 120 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron

[0020] Figure 5b A schematic view of a TM for embodiments of the present disclosure 220 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron 210 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron

[0021] Figure 6a A schematic view of a TM for embodiments of the present disclosure 220 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron 110 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron

[0022] Figure 6b A schematic view of a TM for embodiments of the present disclosure 220 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron 220 A schematic view of a magnetic field distribution of an oscillation mode in an output cavity of a high-order mode klystron

[0023] Figure 7 A schematic view of a TM for embodiments of the present disclosure 220 An assembly view of an output cavity of a high-order mode klystron and an open-ended absorption cavity.

[0024] Wherein the above figures include the following reference signs:

[0025] 1, frame structure

[0026] 11, upper base

[0027] 12, lower base

[0028] 13, connecting piece

[0029] 2, attenuating material body

[0030] 3, mold

[0031] 4, TM 220 Output cavity of a klystron

[0032] 41, drift head

[0033] 42. Electronic injection channel

[0034] 5. Open absorption chamber

[0035] 6. Other types of absorption cavities

[0036] 7. Output waveguide Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0038] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this disclosure.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0040] It should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "mount", "connect", "connect" should be broadly understood, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements inside. The terms "parallel", "perpendicular", "equal" include the described case and the approximate case of the described case, and the approximate case is within the acceptable deviation range, wherein the acceptable deviation range is determined by the person skilled in the art considering the measurement being discussed and the error related to the measurement of a specific quantity (i.e. the limitation of the measurement system). For those skilled in the art, the specific meaning of the above terms in the present application can be understood in specific cases.

[0041] The klystron is a kind of vacuum electron device that converts the direct current energy of the electron beam into microwave energy, and the TM 220 The high-order mode klystron is equivalent to the parallel operation of four fundamental mode klystrons, and theoretically can increase the power capacity and output power to four times. At present, in the field of microwave vacuum devices, the absorption cavity is generally suitable for single mode oscillation suppression of the fundamental mode klystron, while for the TM 220 The high-order mode klystron, the cavity outer edge arrangement mode generally used by the absorption cavity ignores the electromagnetic field concentration area in the center of the cavity, and the electromagnetic field coupling structure of the traditional absorption cavity is difficult to effectively suppress multiple mode oscillation, and welding the absorption cavity in the center area of the cavity also needs to consider the technical problems of deformation and shedding of the attenuation material under stress. In order to solve the above problems, the present disclosure proposes an open type absorption cavity applied to the high-order mode klystron based on the spatial distribution difference of the oscillation mode and the working mode electromagnetic field.

[0042] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0043] Figure 1 A perspective view of the open type absorption cavity provided by the embodiments of the present disclosure is shown.

[0044] Figure 2 A perspective view of the frame structure of the open type absorption cavity of the embodiments of the present disclosure is shown.

[0045] According to an embodiment of the present disclosure, asFigure 1 and Figure 2 As shown, a method for TM is provided. 220 The open absorption chamber of the high-order modulus speed controller is located inside the output chamber of the high-order modulus speed controller. 120 Model and TM 210 The common distribution region of the mode magnetic field, such as Figure 1 and Figure 2 As shown, the open absorption cavity includes a frame structure 1 and an attenuation material body 2 filled within the frame structure 1.

[0046] The frame structure 1 includes an upper base 11 and a lower base 12 arranged in parallel, and multiple connectors 13 that are vertically connected between multiple pairs of aligned corners of the upper base and the lower base. The upper base 11, the lower base 12 and the connectors 13 enclose a cavity structure with open sides, and the attenuating material 2 is filled in the cavity structure.

[0047] The outer surfaces of the attenuating material body 2 are coplanar with the outer peripheral surfaces of the connector 13. The frame structure 1 keeps the outer surfaces of the attenuating material body 2 in an open state, allowing the open outer surfaces to directly contact and couple with the magnetic field generated in the output cavity of the high-order mode speed regulator, thereby achieving the attenuation of the TM. 120 Model and TM 210 Suppression and absorption of the model.

[0048] TM mn A transverse magnetic wave (TM) is a propagation mode in a waveguide where the longitudinal component of the magnetic field is zero, while the longitudinal component of the electric field is not zero. In a rectangular waveguide, the subscript 'm' represents the number of half-cycle changes of the electromagnetic field along the wider side (a) of the waveguide, and the subscript 'n' represents the number of half-cycle changes of the electromagnetic field along the narrower side (b) of the waveguide. A rectangular resonant cavity is equivalent to a waveguide short-circuited at both ends, and the transverse magnetic wave within the resonant cavity is named TM. mnp The subscript p indicates the number of changes in the electromagnetic field along the axial direction (the direction of electron beam propagation in the klystron). The reason the klystron chooses a specific transverse magnetic wave within the resonant cavity as its operating mode is because it possesses a non-zero longitudinal electric field component. The longitudinal direction is also the direction of electron beam propagation, and the electric field in this direction can effectively interact with the electron beam. Similarly, other transverse magnetic wave modes with longitudinal components may also interact with the electron beam and form oscillations. The TM in this disclosure... 220 TM 210 TM 120 All are TM 220 The transverse magnetic wave mode in the rectangular output cavity of the high-order mode speed regulator tube, where the first two digits of the number represent the number of half-cycle changes in the electromagnetic field in the x and y directions, respectively, and the third digit indicates the axial direction. Among them, TM... 220 The mode described in this disclosure is the operating mode of a high-order mode velocity controller, where the electromagnetic field in the x and y directions changes twice per half-cycle. TM 210(x 2, y 1) and TM 120 (x 1, y 2) is TM 220 The non-working oscillation modes of the high-order mode velocity modulation tube are easily excited at the low end of the frequency band, which will interfere with the stability of the working mode.

[0049] According to an embodiment of the present disclosure, based on the difference in the spatial distribution of the electromagnetic field between the working mode and the oscillation mode, the absorption cavity is accurately arranged in the output cavity TM 120 mode and TM 210 The magnetic field of the two non-working oscillation modes is concentrated in the distribution area. At the same time, the frame structure 1 keeps the outer side of the attenuation material body 2 open, so that it is directly exposed to and in contact with the magnetic field environment, and promotes the coupling between the attenuation material body 2 and the magnetic field in the velocity modulation tube, converts electromagnetic energy into heat energy consumption, which can avoid the working mode while absorbing the two non-working mode oscillations to be suppressed. In addition, by making the outer side of the attenuation material body 2 coplanar with the outer peripheral surface of the connecting piece 13, the exposure area of the attenuation material body 2 in the magnetic field distribution area is maximized, effectively enhancing the energy conversion efficiency; the upper base 11, the lower base 12 and the connecting piece 13 in the frame structure 1 form a rigid support, which provides mechanical fixation and stress buffering for the attenuation material body 2, preventing it from being easily broken and falling off under stress.

[0050] According to an embodiment of the present disclosure, the material of the frame structure 1 should be selected from metal materials with good electrical conductivity and thermal conductivity, and there should be no obvious evaporation phenomenon in a vacuum environment. Generally, oxygen-free copper is selected as the material of the frame structure 1, and an integrated frame structure is obtained through overall processing. Oxygen-free copper has good electrical conductivity and thermal conductivity and no evaporation phenomenon, and can quickly conduct the heat generated by the electromagnetic energy conversion of the attenuation material body 2, preventing local overheating from affecting the performance of the device. In addition, the integrated frame structure can eliminate the splicing gap, has higher structural strength and rigidity, provides stable support and reliable stress buffering for the attenuation material body 2, and ensures long-term stable operation of the device.

[0051] According to an embodiment of the present disclosure, the attenuation material body 2 is formed by sintering and solidifying attenuation material, wherein the attenuation material mainly contains elements such as iron, silicon and aluminum, which mainly couples with the magnetic field to realize the conversion of electromagnetic energy into heat energy. In addition, the attenuation material may also contain other transitional auxiliary materials, such as adhesives used in the preparation stage of the attenuation material (which will be discharged by the hydrogen furnace in the sintering stage). According to an embodiment of the present disclosure, at room temperature, the attenuation material is in a semi-liquid state with a certain viscosity before sintering.

[0052] According to another embodiment of the present disclosure, a preparation method of the above open absorption cavity is provided, Figure 3a is a cross-sectional view of the open absorption cavity prepared by using a mold according to an embodiment of the present disclosure. Figure 3bThis is a schematic cross-sectional view of the mold according to an embodiment of the present disclosure.

[0053] According to embodiments of this disclosure, such as Figure 3b As shown, suitable for making Figure 1 The mold 3 for the open absorption cavity shown includes a bottom mold 31 and at least two opposing lateral constraint molds 32. The bottom mold 31 and the lateral constraint molds 32 respectively contact three sides of the frame structure 1 to form constraints. In practical applications, the bottom mold 31 and the lateral constraint molds 32 can be processed as a whole. The mold 3 can cooperate with at least three sides of the frame structure 1 to form a stable constraint structure. The tightness of the contact between the mold 3 and the frame structure 1 must be sufficient to prevent the overflow of viscous semi-liquid decay material, thereby preventing the decay material from overflowing during the casting process.

[0054] like Figure 3a As shown, the method for preparing an open absorption cavity includes: providing... Figure 3b The mold 3 shown is adapted to the frame structure 1. The frame structure 1 is placed in the mold 3. A viscous semi-liquid attenuation material is poured into the mold 3, so that the attenuation material fills the cavity structure of the frame structure 1. The attenuation material is semi-cured at a semi-curing temperature. The frame structure filled with the semi-cured attenuation material is demolded from the mold 3. In a hydrogen furnace, the demolded frame structure filled with the semi-cured attenuation material is heated to the sintering temperature to completely cure the attenuation material. After cooling, attenuation material 2 is obtained and connected to the frame structure 1 to obtain an open absorption cavity.

[0055] According to the above preparation method, an auxiliary shaping mold 3 adapted to the frame structure 1 is used to ensure the filling and shaping of the attenuation material. The viscous, semi-liquid attenuation material is poured into the mold 3 for semi-curing, allowing it to initially solidify within the frame structure 1. This effectively avoids stress damage between the attenuation material body 2 and the frame structure 1 caused by demolding after complete curing. After semi-curing, the material is demolded, sintered in a hydrogen furnace, and cured. The fully cured attenuation material body 2 forms a locking structure with the open absorption cavity base. Unless the attenuation material undergoes severe breakage, it will not detach from the frame structure 1, thus ensuring the stability and reliability of the absorption cavity.

[0056] According to embodiments of this disclosure, the mold 3 is made of a blackened metal material. The material treated with a high-temperature blackening process forms a dense oxide film on its surface, significantly improving the mold's corrosion resistance and wear resistance. Simultaneously, it reduces the coefficient of friction on the mold surface, effectively preventing adhesion between the mold and the frame structure material, thus facilitating subsequent demolding.

[0057] In an exemplary embodiment, the blackened stainless steel can be selected as the mold material to prepare a "U" shaped mold comprising a bottom mold 31 and two opposite lateral constraint molds 32, which can be optionally integrally machined.

[0058] According to an embodiment of the present disclosure, pouring the viscous semi-liquid attenuation material into the cavity structure of the frame structure 1 comprises: taking the upper side of the frame structure 1 which is not in contact with the bottom mold 31 and the lateral constraint mold 32 as a pouring channel, pouring the viscous semi-liquid attenuation material into the cavity structure of the frame structure 1, until the upper surface of the attenuation material is flush with the side surface of the frame structure 1, to ensure that the attenuation material sufficiently fills the cavity structure.

[0059] According to an embodiment of the present disclosure, the semi-curing temperature is 40-50℃, for example, it can be 40℃, 42℃, 45℃, 47℃, 50℃, etc., and the semi-curing time is 7-12 hours, for example, it can be 7 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc. In actual application, the attenuation material can be semi-cured in an oven, and after low-temperature drying, the attenuation material can be initially formed to realize demolding and provide a basis for subsequent complete curing treatment.

[0060] According to an embodiment of the present disclosure, the sintering temperature in the hydrogen furnace is 1000±20℃, and since the frame structure 1 uses oxygen-free copper, its melting point is about 1080℃, so if the sintering temperature is too high, the frame structure 1 will melt. The sintering temperature in the hydrogen furnace is maintained for more than 45 minutes, preferably 45 minutes to 1 hour. At the sintering temperature, the attenuation material can be fully cured to form a stable structure. If the temperature is too high or too low, it may cause the internal structure of the attenuation material to increase in defects or decrease in performance, thereby affecting its mechanical and electromagnetic properties.

[0061] In actual operation, when the open-type absorption cavity filled with semi-cured attenuation material is placed in the hydrogen furnace for sintering, the hydrogen furnace should be filled with wet hydrogen containing moisture. In this way, while hydrogen gas is used as the reducing gas, the moisture in the wet hydrogen will react with the nitrocellulose that plays a role in bonding the attenuation material under high temperature conditions, and the nitrocellulose is converted into a gas which is then discharged as process tail gas. As the nitrocellulose is removed, the space originally occupied by it forms a honeycomb-like void structure, which is beneficial to improving the attenuation amount of the final product.

[0062] According to still another aspect of the embodiments of the present disclosure, an application of the above open-type absorption cavity is provided, comprising: in a TM 220 The open-type absorption cavity is arranged at the center position of the output cavity of the high-order mode klystron, so as to realize suppression and absorption of TM 220 TM 120 mode and TM 210 mode in the high-order mode klystron, wherein the center position is TM 120Mode and TM 210 Mode magnetic field concentration distribution area.

[0063] TM 220 High-order mode klystron, working in TM 220 High-order mode state, equivalent to four parallel base mode klystrons, can multiply the output power under lower cathode load. In recent years, this direction has made great progress in international and domestic research.

[0064] According to the embodiments of the present disclosure, TM 220 When the high-order mode klystron is working, a plurality of low-order non-working oscillation modes that may be generated in the output cavity will interfere with the working mode and affect the performance of the klystron. The open absorption cavity of the present disclosure is placed at the center position of the cavity, which can maximize the coupling with the surrounding electromagnetic field through its special open structure, and suppress TM 120 Mode and TM 210 Mode two non-working oscillation modes, to ensure TM 220 The pass rate, working stability and spectrum quality of the high-order mode klystron can provide new technical solutions for the engineering application of the high-order mode klystron.

[0065] Figure 4a For the embodiments of the present disclosure, TM 220 The plan view of the output cavity of the high-order mode klystron; Figure 4b For the embodiments of the present disclosure, TM 220 The cross-sectional view of the output cavity of the high-order mode klystron along the M-M line.

[0066] In an illustrative embodiment, as shown in Figure 4a and 4b TM 220 The high-order mode output cavity 4 includes four drift heads 41; each drift head 41 has 7 electron beam channels 42, which are electron beam transmission channels. TM 220 The high-order mode klystron is theoretically equivalent to the parallel connection of four base mode resonant cavities, so the power capacity is four times that of the base mode cavity. TM 220 The high-order mode output cavity 4 is divided into four parts according to the area where the drift head 41 is located, and the positions of four points A, B, C and D at the boundary of the area are selected, and an open absorption cavity 5 is arranged at the center point position 0. Among them, position B needs to be provided with an output waveguide for transmitting TM 220 The microwave energy formed by the energy exchange of the electron beam in the output cavity of the high-order mode klystron is transmitted to the external load, so position B cannot be placed with an absorption cavity, and positions A, C, D and 0 are positions where the absorption cavity can be placed.

[0067] According to the embodiments of the present disclosure, the non-working oscillation modes that can be suppressed include TM 120 Mode and TM210 In practical applications, the open absorption cavity is placed in the region where the magnetic lines of TM 210 mode and TM 120 mode pass through together. The open absorption cavity can ensure that the attenuation material body is in sufficient contact with the magnetic fields of the two oscillation modes in multiple directions, and simultaneously attenuate the two oscillation modes.

[0068] According to the embodiments of the present disclosure, in practical applications, the open absorption cavity can also be used in cooperation with other types of conventional absorption cavities, further widening the coverage of the oscillation modes, and improving the suppression effect on the high-order mode velocity modulation tube oscillation modes.

[0069] Figure 5a For the embodiments of the present disclosure, TM 220 mode in the output cavity of the high-order mode velocity modulation tube, TM 120 mode magnetic field distribution diagram; Figure 5b For the embodiments of the present disclosure, TM 220 mode in the output cavity of the high-order mode velocity modulation tube, TM 210 mode magnetic field distribution diagram.

[0070] In an illustrative embodiment, as Figure 5a shown, where "H" represents the magnetic field, and the arrows and closed loop lines represent the magnetic lines of the magnetic field. At positions 0, B, and D, the magnetic lines of TM 120 mode pass through, and placing an absorption cavity at the above positions can absorb TM 120 mode; at positions A and C, the magnetic lines of TM 120 mode pass through, and placing an absorption cavity at the above positions has no effect on TM 120 mode. As Figure 5b shown, at positions 0, A, and C, the magnetic lines of TM 210 mode pass through, and placing an absorption cavity at the above positions can absorb TM 210 mode; at positions B and D, the magnetic lines of TM 210 mode pass through, and placing an absorption cavity at the above positions has no effect on TM 210 mode. Therefore, the magnetic lines of TM 120 mode and TM 210 mode pass through position 0 together, and the magnetic lines of the two oscillation modes cover the four directions of up, down, left, and right at position 0, and placing the open absorption cavity of the present disclosure at this position can simultaneously attenuate TM 120 mode and TM 210 mode oscillation.

[0071] Figure 6a For the embodiments of the present disclosure, TM 220 mode in the output cavity of the high-order mode velocity modulation tube, TM 110 mode magnetic field distribution diagram;Figure 6b For the embodiment of the present disclosure TM 220 TM mode in the output cavity of a high-order mode klystron 220 Magnetic field distribution diagram of working mode.

[0072] In an exemplary embodiment, TM 110 Oscillation mode is TM 220 The fundamental mode in the high-order mode klystron exists in the absorption cavity as a possible oscillation mode. As Figure 6a shown, from the magnetic field distribution, there is no TM 110 oscillation mode passing through at the position 0 area, where the absorption cavity is set to be ineffective to it, but there is TM 110 oscillation mode passing through at the four positions A, B, C, and D, where the absorption cavity is set to be effective to TM 110 oscillation mode. In addition, TM 220 mode is working mode, as Figure 6b shown, there is no magnetic field passing through at the positions 0, A, B, C, and D, that is, the absorption cavity is theoretically not absorbed at the five positions.

[0073] According to the above setting mode, in addition to the output waveguide at the position B, the absorption cavity cannot be placed, the absorption cavities at the positions 0, A, C, and D can be placed together to absorb TM 110 , TM 120 , and TM 210 three oscillation modes. Among them, the position 0 area can simultaneously absorb TM 120 and TM 210 two oscillation modes, so the open absorption cavity of the embodiment of the present disclosure is placed at the position 0 area, which can realize effective suppression of TM 120 and TM 210 two oscillation modes.

[0074] Figure 7 For the embodiment of the present disclosure TM 220 high-order mode klystron output cavity and open absorption cavity assembly diagram.

[0075] According to the embodiment of the present disclosure, as Figure 7 shown, the open absorption cavity 5 of the present disclosure is set in TM 220The center position 0 area of the output cavity 4 of the high-order mode velocity modulation tube is fixedly connected to the inner wall surface at the center position of the output cavity 4 through brazing, and the solder used for welding is gold-based solder. Since the area where the open absorption cavity is welded is the area where the electromagnetic field energy is concentrated, a large amount of heat will be generated during the operation process. If the solder melts due to high temperature, there will be a greater hidden danger. Therefore, gold-based solder with a high melting point and less evaporation is selected, such as gold-copper solder, to ensure the structural strength and reliability of the welded part.

[0076] Further, other types of absorption cavities 6 can be arranged at positions A, C, and D, and an output waveguide 7 is arranged at position B, so that no absorption cavity can be arranged. By fully utilizing the magnetic field distribution characteristics at different positions and reasonably arranging the absorption cavities, the effective suppression of TM 120 , TM 210 two non-working oscillation modes is realized, and interference with the working mode TM 220 is avoided, thereby improving the performance and stability of the TM 220 velocity modulation tube.

[0077] In an illustrative embodiment, the welding of the open absorption cavity 5 and the TM 220 high-order mode output cavity 4 is preferably "face-to-face" welding, that is, the welding surface of the open absorption cavity is fully bonded and welded with the corresponding welding surface of the output cavity. Compared with the "point-to-point" welding method which realizes connection only through local welding points, the "face-to-face" welding method has a larger contact area, which can significantly reduce the contact thermal resistance. The "point-to-point" welding method is prone to form a larger contact thermal resistance, resulting in the occurrence of a local high-temperature area. When the velocity modulation tube outputs high power, the local high-temperature area may melt due to overheating, thereby affecting the working stability.

[0078] The open absorption cavity provided by the present disclosure for the high-order mode velocity modulation tube is based on the spatial distribution difference of the oscillation mode and the working mode electromagnetic field, and realizes sufficient coupling with the surrounding electromagnetic field through its unique open structure, which can avoid the working mode while simultaneously absorbing TM 210 , TM 120 two non-working oscillation modes. The frame structure of the open absorption cavity can effectively fix and protect the internal attenuation material body without affecting the absorption effect, thereby ensuring the stability and reliability of the internal attenuation material body during the operation of the high-order mode velocity modulation tube. In addition, the preparation method of the open absorption cavity is simple and easy to operate, and is easy to realize large-scale production. The TM 220 high-order mode velocity modulation tube using the open absorption cavity can significantly improve the direct current passing rate and the frequency spectrum quality, enhance the working stability, and reduce the spur level, thereby providing a solution for the efficient and stable operation of the high-order mode velocity modulation tube.

[0079] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present disclosure, and it should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A device for TM 220 The open absorption chamber of the high-order modulus speed regulator is located in TM. 220 High-order modulus speed control tube output cavity TM 120 Model and TM 210 The common distribution region of the modal magnetic field is characterized by, The open absorption cavity includes a frame structure and an attenuating material body filled within the frame structure, wherein... The frame structure includes an upper base and a lower base arranged in parallel, and multiple connectors that are vertically connected between multiple pairs of aligned corners of the upper base and the lower base. The upper base, the lower base, and the connectors enclose a cavity structure with open sides, and the attenuating material is filled in the cavity structure. The outer surfaces of the attenuating material are respectively coplanar with the outer peripheral surfaces of the connector. The frame structure keeps the four outer surfaces of the attenuating material in an open state, so that the open outer surfaces are aligned with the TM. 220 The magnetic field generated within the output cavity of the high-order modulus throttle tube directly contacts and couples with the TM, enabling control of the TM. 120 Model and TM 210 Suppression and absorption of the model.

2. The open absorption cavity according to claim 1, characterized in that, The frame structure is made of oxygen-free copper.

3. The open absorption cavity according to claim 1, characterized in that, The attenuation material body is formed by sintering and solidifying an attenuation material, wherein the attenuation material contains iron, silicon, and aluminum elements.

4. A method for preparing an open absorption cavity as described in any one of claims 1 to 3, characterized in that, The preparation method includes: A mold adapted to the frame structure is provided, and the frame structure is placed in the mold; A semi-liquid attenuating material is poured into the mold, so that the attenuating material fills the cavity structure of the frame structure. The attenuating material is semi-cured at a semi-curing temperature. After the semi-curing is completed, the frame structure filled with the semi-cured attenuating material is demolded from the mold. In a hydrogen furnace, the demolded frame structure filled with semi-cured attenuation material is heated to the sintering temperature to completely cure the attenuation material and connect it to the frame structure. After cooling, the open absorption cavity is obtained.

5. The preparation method according to claim 4, characterized in that, The semi-curing temperature is 40~50℃, and the semi-curing time is 7~12 hours; The sintering temperature is 1000±20℃; The sintering temperature is maintained for more than 45 minutes.

6. The preparation method according to claim 4, characterized in that, The mold includes a bottom mold and at least two opposing lateral constraint molds, which respectively contact the three sides of the frame structure and form constraints.

7. The preparation method according to claim 6, characterized in that, Pouring a semi-liquid damping material into the cavity structure of the frame structure includes: Using the upper side of the frame structure that does not contact the bottom mold and the lateral constraint mold as a pouring channel, a semi-liquid attenuating material is poured into the cavity structure of the frame structure until the upper surface of the attenuating material is flush with the side of the frame structure.

8. The preparation method according to claim 4, characterized in that, The mold is made of a blackened metal material.

9. An application of the open absorption cavity according to any one of claims 1 to 3, characterized in that, The applications include: In TM 220 The open absorption cavity is located at the center of the output cavity of the high-order modulus speed regulator to achieve the absorption of the TM. 220 In high-order modulus speed control tube TM 120 Model and TM 210 Suppression and absorption of the modulus, wherein the central position is TM 120 Model and TM 210 The magnetic field of the model is concentrated in a specific region.

10. The application according to claim 9, characterized in that, The upper and lower bases of the open absorption cavity are fixedly connected to the inner wall surface at the center of the output cavity by brazing. The solder used in the welding is a gold-based solder.

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