JPH0517792Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) This invention relates to a coaxial waveguide structure equipped with a dielectric hermetic window plate, which is applied to the output section of a microwave electron tube such as a klystron. . (Prior art) The structure of the output section of a microwave electron tube such as a klystron is a coaxial waveguide in which a coaxial waveguide is connected to the output cavity and a rectangular waveguide is connected to the tip of the coaxial waveguide.
A rectangular waveguide transducer may be provided. At the tip of the coaxial waveguide structure, an airtight window plate made of ceramic dielectric, called an airtight window, is provided in a vacuum-tight manner. An example of a schematic configuration of a beam rectilinear multi-cavity klystron having such a coaxial waveguide structure will be explained with reference to FIG. The klystron main body includes an intermediate resonant cavity 11, a drift tube 12, an output cavity 13, and a collector section 14, which are part of the klystron body and are arranged in a vertical line along the tube axis. A coaxial waveguide structure 15 constituting an output section is hermetically connected to a part of the cavity wall of the output cavity 13. This coaxial waveguide structure 15 has an inner conductor 16 and an outer conductor 17, and cooling water is circulated through the inner conductor 16 as shown by arrow Q and also through the outer conductor (not shown). . The diameters of both the inner and outer conductors are expanded from the middle and converted into a large diameter inner conductor portion 18 and a large diameter outer conductor portion 19, and a dielectric airtight window plate 20 is provided between the two conductors in these large diameter portions to ensure vacuum tightness. It is joined. Both conductors are divided in the axial direction on the part at dividing parts 18a and 19a inward from the position of the airtight window plate 20, and both conductors are electrically and vacuum-tightly integrated at these parts by arc welding or the like. become combined. The tip of this coaxial waveguide structure 15 is connected to a rectangular waveguide 21 . That is, the tip flange portion of the large diameter portion 19 of the outer conductor is a rectangular waveguide 21.
The tip 18b of the large-diameter inner conductor 18 is connected to the opening in the wide surface 22 of the doorknob-shaped extension 23.
are electrically and mechanically connected to the opposing wide faces 24 of the rectangular waveguide via. Note that the open flange 25 of the output waveguide is connected to an external load circuit. (Problems to be Solved by the Invention) In particular, with this type of coaxial waveguide structure used for ultra-high power applications, the greatest concern is damage to the dielectric airtight window plate due to overheating and high-frequency arc discharge. The vacuum side surface of the dielectric airtight window plate is coated with a coating layer for preventing multipactor discharge. Further, in order to forcibly cool the dielectric airtight window plate from the outside, a structure is adopted in which the thin cylinder on the inner conductor side and the thin cylinder on the outer conductor side are directly cooled with water. Furthermore, a structure in which the surface of the airtight window plate facing the atmosphere is air-cooled by cooling air is effective.
In order to make this air cooling even more effective, another dielectric partition plate is fitted between the inner and outer conductors at a predetermined distance from the airtight window plate to form a cavity between them.
It is also being considered to introduce cooling air from the outside so that the cooling air can be blown onto the atmosphere side surface of the airtight window plate. On the other hand, the added dielectric partition plate becomes a hindrance, which prevents external monitoring of the temperature of the airtight window plate and the presence or absence of high-frequency arc discharge in the vicinity. Damage to any part of this type of ultra-high power klystron can lead to a fatal inability to operate the entire unit, so it is necessary to accurately detect the airtight window panel and its surroundings to control the klystron's operation with high precision. There is. In view of the above-mentioned circumstances, the purpose of this invention is to provide a coaxial waveguide structure configured to accurately monitor and detect the atmosphere-side surface of the dielectric airtight window plate and its surroundings from the outside. . [Structure of the invention] (Means for solving the problem) This invention is based on a dielectric airtight window plate that is vacuum-tightly sealed between an inner conductor and an outer conductor, and which is exposed to the atmosphere at a predetermined interval. This is a coaxial waveguide structure in which the arranged dielectric partition disks are made of a light-transmitting material, or in which small through holes are formed in some parts. (Function) According to this invention, the temperature of the dielectric airtight window plate or the presence or absence of high-frequency arc discharge in the vicinity can be determined through the through hole formed in the dielectric partition disk itself or a part of the partition disk. Can be accurately detected from the outside. (Example) An example of this invention will be described below with reference to the drawings. Note that the same parts are indicated by the same symbols. An example in which this invention is applied to a beam-travel type multi-cavity klystron will be explained with reference to FIGS. 1 to 6. An output coaxial waveguide structure 30 is vacuum-tightly connected to an output cavity of a klystron main body (not shown). The coaxial waveguide structure 30 has an airtight window structure 60 in a part thereof. That is, an airtight window plate 34 made of ceramic dielectric is vacuum-tightly joined between the inner conductor 31 and the large diameter portion 33 of the outer conductor 32. In addition, near the airtight window plate 34 on the atmosphere side,
A dielectric partition disk 35 is mechanically fixed.
The outward extension 36 on the atmosphere side of the inner conductor is a doorknob-shaped extension 3 formed by forming a thin dielectric plate into a bowl shape.
7. This doorknob-like extension 37 is electrically and mechanically connected to one wide side 39 of the output rectangular waveguide 38 . The inner conductor extension part 36 is configured so that cooling water can be circulated therein as shown by arrow P. The tip flange 40 of the large diameter outer conductor portion 33 is connected to the other wide surface 41 of the rectangular waveguide through its opening. The inner conductor outwardly extending portion 31a and the outer conductor outwardly extending portion 32a on the vacuum region side are coupled to the output cavity as described above. Both conductors are constructed so that cooling water can be circulated inside them as shown by arrow Q. In this way, a converting section from a coaxial waveguide to a rectangular waveguide at the output section of the klystron is constructed. Next, the structure of each part will be explained in accordance with the preferred assembly order. The outer extension portions 31a and 32a of the inner and outer conductors constituting the coaxial waveguide structure 30 are respectively made of a large-diameter inner conductor bottomed cylindrical portion 42 made of copper, an outer conductor funnel-shaped portion 43 having a tapered inner surface, and an outer conductor. An outer first high frequency matching cylinder 44 having a large diameter portion is provided. The inner conductor bottomed cylindrical portion 42 has an inner first alignment cylindrical portion 45 and three recesses 46, 47, and 48 on the inner side. A stepped reinforcing disk 49 made of a material with high mechanical strength such as stainless steel is fitted into the bottom portion 48 . The inner conductor bottomed cylindrical portion 42 also has a minute ventilation hole 50 and a female screw portion 51 for positioning bored in a part of the outer periphery. The first outer aligning cylinder 44 has an aligning cylindrical portion 52 at the tip, and a fixing flange 53 and an airtight sealing flange 54 made of thin stainless steel are joined to the outer periphery. A plurality of tightening bolts 55, which will be described later, are inserted into the fixing flange 53. A through hole 57 for inserting a positioning tool 56 is formed in a portion of the outer conductor funnel-shaped portion 43 and the cylinder 44 . The ends of the structure of the outer extension portion of the inner and outer conductors described above are integrally fixed to the output cavity of the klystron. On the other hand, the airtight window structure 60 having the dielectric airtight window portion 34 is assembled separately as follows. That is, a thin cylinder 61 is hermetically sealed to the outer peripheral surface of the dielectric airtight window plate 34 made of ceramics.
A cooling jacket cylindrical body 63 forming an annular cooling chamber 62 for water cooling is joined to its outer periphery. Cooling water can be introduced and discharged into the annular cooling chamber 62 from the outside as indicated by arrow R. A plurality of micro ventilation holes 64 are formed radially at the end of the cylindrical body 63 on the atmosphere side, and an airtight flange 65 made of thin stainless steel is joined to the outer periphery of the end on the vacuum side. A plurality of female screw holes 63a are formed in the upper end surface of the cylindrical body 63, and a fixing ring 63b is fitted around the outer periphery and is secured to the bulge 63c. A thin cylinder 66 is hermetically soldered to the inner peripheral surface of the central hole of the dielectric airtight window plate 34, and an inner conductor connecting ring 68 and An inner cylinder 69 is fixed. The inner conductor connecting ring 68 has an outer circumferential diameter Db that is slightly larger than the inner diameter dimension Da of the stepped inner circumferential wall 47a of the inner conductor bottomed cylindrical portion 42 in a component state. In addition, this has a female screw hole 70 in the center, and the opening is a thin airtight bulkhead plate 71 made of copper.
It is vacuum-tightly closed. In this way, the ring 68 constitutes an airtight closing portion of the inner conductor portion that is sealed to the dielectric airtight window plate. As a result, the inner region of the outer conductor portion of the airtight window structure 60 is vacuum-tightly closed by the dielectric airtight window plate 34 and the inner conductor connecting ring 68 having an airtight closing portion.
In the inner cylinder 69, a plurality of sets of through holes 72 and 73 for circulating cooling water into the cooling chamber 67 are formed radially corresponding to both ends of the cooling chamber. Further, a second inner matching cylindrical member 75 made of copper and having an inner joining cylindrical portion 74 is connected to the upper end of the inner cylinder 69 . The alignment cylindrical portion 74 surrounds the thin cylinder 66 at a predetermined interval, and has a distal end extending to the vicinity of the airtight window plate. Further, a plurality of ventilation holes 76 parallel to the axial direction are formed at the bottom thereof. Note that a coating layer (not shown) for preventing multipactors is applied to the inner surface of the dielectric airtight window plate 34. As described above, this airtight window structure 60 is assembled by itself. In this way, the airtight window structure 60 , which consists of nine parts of the dielectric airtight window structure that are airtightly joined between the inner and outer conductors, can be assembled independently from the tube body, making these airtight joints extremely reliable. It is easy to create a bonded structure with high properties. Especially among dielectric airtight window plates,
It is easy to form an airtight joint on the outer circumferential surface and to apply a coating layer for preventing multipactors in a highly reliable manner. Now, the airtight window structure 60 prepared in this way is
Connect to the ends of the inner and outer conductor extensions extending from the output cavity as follows. That is, first, a small electric heating furnace 7 that can locally heat the inner conductor bottomed cylindrical portion 42 is used.
7 and locally heat this cylindrical part. Note that in order to accurately maintain the concentric positions of the inner conductor and the outer conductor, a positioning jig 56 is screwed between them. Then, when the cylindrical part 42 reaches a predetermined temperature and is thermally expanded, the electric heating furnace is immediately removed, the airtight window structure 60 is fitted thereon, and the tip of the inner conductor connecting ring 68 is thermally expanded. It is inserted or press-fitted into the stepped inner circumferential wall 47a of the cylindrical portion 42. Thereafter, when the inner conductor is cooled to room temperature, the connecting ring 68 and the cylindrical portion 42 of the inner conductor are mechanically and electrically coupled to each other in a tight fit state by shrink fitting. The joint portion formed by this close shrink-fitting is designated by the reference numeral 10 . In this state, both sealing flanges 5 on the outer conductor side
4 and 65 conform to the gassho structure, so their entire circumferences are hermetically welded by arc welding. Further, the fixing flanges 53 and 63b are tightened and fixed with bolts 55. In this way, the outer conductor large-diameter portions 33 are vacuum-tightly connected to each other, and the outer conductor cylinders 44 and 63 are electrically press-connected. After the two have been combined,
The positioning jig 56 is removed, and the through hole 57 is vacuum-tightly sealed with a sealing member 72. By assembling in this way, the inner conductor thin cylinder 66 connected to the dielectric airtight window plate 34 has an inner first cylinder 66 at a predetermined slight interval on the outer periphery.
An alignment cylindrical portion 45 is located there. This inner first matching cylindrical part 45, a second matching cylindrical part 74 on the atmosphere side that closely opposes this with an airtight window plate in between, and a conductive wall including a thin cylinder 66 are used for outer conductor side matching, which will be described later. Together with the annular groove, a matching annular groove C is formed to eliminate impedance discontinuity in the vicinity of the dielectric airtight window plate to prevent electromagnetic wave reflection and to obtain high frequency matching. The matching cylinder parts 45 and 74 that are closely opposed each other also function to shield the airtight soldered joint between the thin cylinder 66 and the airtight window plate 34 from high frequency electromagnetic fields. The airtight soldered joint between the airtight window plate 34 and the thin cylinder 66 is located approximately inside this annular groove C, and almost no high frequency current flows therethrough, so that the joint is protected. Further, since the connecting portion 10 connected by shrink fitting is also located at the inner part of the matching annular groove C, no high frequency current flows there, and the reliability of the mechanical and electrical connection is maintained high. In this way, the inner conductor is integrally connected to each other by shrink fitting and the outer conductor is subsequently welded. Next, on the cooling jacket cylindrical body 63, a partition plate holding ring 80 having a second outer matching cylinder part 79 and forming a part of the outer conductor part is screwed into the female screw hole 63a with the fixing bolt 81. Fix the connection by doing this. Therefore, a partition disk made of a dielectric material with low high frequency loss such as Teflon (trade name) is installed at the inner step 80a of this ring 80 and the step 75a of the inner second matching cylindrical member 75 on the inner conductor side. 53 into the central hole 35a. This partition disk 35 is
This prevents the cooling air, which will be described later, from escaping to the outside, ensures that it hits the entire surface of the airtight window plate 34 on the atmosphere side, and increases the mechanical holding strength of the inner conductor and outer conductor. A circumferential groove 8 is provided on the surface of the partition disk 35 to improve high frequency withstand voltage.
2 are formed coaxially. A relatively small through hole 83 for monitoring the airtight window plate is bored in a part of the dielectric partition disk 35. Note that each outer alignment cylindrical portion 79 and 5
2. The thin cylinder 61 forms a matching annular groove C for obtaining high frequency matching near the dielectric airtight window plate, as described above. In addition, similarly to both the matching cylinder parts 79 and 52 that are close to each other, the thin cylinder 61 and the airtight window plate 3
It acts to shield the airtight soldered joint with 4 from high frequency electromagnetic fields. As a result, the contact parts of the outer thin cylinder 61 and the outer conductor are located inside this matching annular groove C, so that almost no high-frequency current flows there, and high reliability of each joint is maintained, and high-frequency external leakage is prevented. Furthermore, on the inner second alignment cylindrical member 75,
Refrigerant guide member 8 that guides cooling water and cooling air
4 through an O-ring 85. This coolant guide member 84 has a substantially cylindrical shape, and has four cooling air passage through holes 84a parallel to the axial direction, and four cooling water passage through holes radially located at positions offset from the cooling air passage holes 84a in the circumferential direction. 84b are drilled alternately. A cylinder 86 constituting the outwardly extending portion 36 of the inner conductor and a partition wall cylinder 87 for a refrigerant passage inside the cylinder 86 are soldered to this refrigerant guide member 84 . These cylinders have an upper end flange 8
8 and 89 are joined. The doorknob-shaped extension 37 is connected and fixed to the upper end flange 88 with bolts 90 . Furthermore, pipes 91a and 91b for guiding the refrigerant are inserted into the center hole of the cylinder 69 inside the hollow inner conductor portion and fixed in a liquid-tight manner. A pipe 92a for blowing cooling air is attached to the flange 89, and a hose 9 for introducing cooling water is attached to the inner guide pipe 91a.
2b, and the flange 89 is further equipped with a drainage hose 9.
2c is connected and extended outside the waveguide. Note that these are mechanically held and fixed to a support plate 94 by pillars 93. In this way, when operating,
Cooling water circulates through each part of the inner conductor as shown by arrow P to cool the inner conductor. Also, the cooling air is supplied to the atmosphere side ventilation hole 7 of the inner second matching member as indicated by the dotted arrow S.
6 and is introduced so as to be sprayed onto the surface of the dielectric airtight window plate 34 through the inner matching annular groove C. The flow of the cooling air is regulated in the radial direction by the space T defined by the airtight window plate 34 and the partition disk 35, and is formed in the outer cylinder through the matching circulation groove C formed by the second outer matching cylinder 79. It is discharged to the outside from the ventilation hole 64. These ventilation holes 76 and 64 formed in the inner and outer conductor parts not only have dimensions that block high frequencies, but are also located inside the annular groove for inner and outer matching. Therefore, as described above, leakage of high frequency waves to the outside from these vents is reliably suppressed. On the outer conductor side, the partition plate holding ring 80
A flange 40 is connected and fixed by bolts 96 through an O-ring 95 made of a conductor, and this flange 4
0 is integrally fixed to the rectangular waveguide 38. The waveguide 38 is provided with a connection flange 97 for connection to an external load circuit. Now, at a predetermined position of the thin conductive plate constituting the doorknob-shaped extension part 37, there is a through hole 9 having a high frequency shielding size.
8 is provided. Thereby, the temperature of the dielectric airtight window plate 34 or the presence or absence of high frequency arc discharge in the vicinity can be detected through the through hole 98 and the small through hole 83 formed in the dielectric partition disk 35. For that purpose, a sensor device 99 for detecting temperature or arc is housed in the bowl-shaped inner space U of the thin conductor plate constituting the doorknob-shaped extension. As shown by the two-dot chain arrow in FIG. 6, the state of the airtight window plate 34 and its vicinity can be monitored from the outside through both monitoring through holes 98 and 83. Of course, the sensor device may be provided outside the waveguide, or may be attached and used only when monitoring is necessary. Note that the dielectric partition plate 35 may be formed of other low-loss dielectric materials. If the material is non-transparent, one or more monitoring holes are formed at arbitrary positions on the circumference. Further, the partition plate 35 may be formed of a relatively transparent dielectric material such as quartz glass, and in that case, a monitoring through hole is not required. This invention is not only applicable to high-frequency coupling parts between coaxial waveguides and rectangular waveguides, but also includes a dielectric secret plate between the inner conductor and the outer conductor, and a dielectric plate placed at a predetermined distance on the atmosphere side. It can be widely applied to various coaxial waveguide structures in which partition plates are arranged. [Effects of the invention] As explained above, according to this invention, high frequency waves at or near the temperature of the dielectric airtight window plate can be The presence or absence of arc discharge, etc. can be accurately detected from the outside.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of this invention, Fig. 2 is an exploded sectional view of the main parts, Fig. 3 is a top view of the main parts, and Fig. 4 is a cross-sectional view of the main parts. FIG. 5 is a perspective view of the main parts, FIG. 6 is an enlarged sectional view of the main parts of this invention, and FIG. 7 is a schematic diagram illustrating the conventional structure. 30 ... Coaxial waveguide structure, 31... Inner conductor, 3
2... Outer conductor, 34... Dielectric airtight window plate, 35...
...dielectric partition disk, 37...doorknob-shaped extension part,
38... Rectangular waveguide, 83, 98... Through hole, 99
...Sensor device, 60 ...Airtight window structure.

Claims (1)

[Claims for Utility Model Registration] A dielectric airtight window plate is vacuum-tightly sealed between the inner conductor and the outer conductor, and a dielectric partition plate is placed on the atmosphere side at a predetermined distance from the dielectric airtight window plate. A coaxial waveguide structure in which the dielectric partition plate is made of a translucent material or has a small through hole formed in a part of the coaxial waveguide structure. Structure.