Vacuum interface valve for horizontal cold finger of POPTOP type germanium detector

Abstract

The utility model discloses a vacuum interface valve for a horizontal cold finger of a POPTOP type germanium detector, which belongs to the technical field of nuclear radiation detector hardware, solves the technical problem that the energy resolution of the horizontal cold finger of the detector becomes poor due to a vacuum fault, and comprises a fixing unit, an interface valve unit and a bottom plate fixing screw. The fixing unit comprises a fixing ring and a fixing panel. The connector valve unit comprises a pull rod, an end spring, a fixing bottom plate, a cylindrical sleeve type sealing ring, a shell, a sealing nut, a fixing nut, an O-shaped ring, a handle and a KF40 connector. The pull rod is fixedly connected with the shell through the fixing nut, the fixing bottom plate and the shell are of an integral structure, the pull rod sequentially penetrates through the fixing nut, the sealing nut, the O-shaped ring, the shell and the fixing bottom plate, and the fixing bottom plate and the fixing panel are fixedly connected through the bottom plate fixing screw. The vacuum interface valve is used for the horizontal cold finger of the detector.

Description

Technical Field

[0001] The utility model belongs to the technical field of hardware of nuclear radiation detectors, and particularly relates to a vacuum interface valve for a horizontal cold finger of a POPTOP type germanium detector. Background Art

[0002] Semiconductor detectors are important devices for testing the γ energy spectrum of radionuclides. Among them, germanium detectors have good advantages in energy resolution, so they have many applications in fields such as radiation environment monitoring, nuclear power plants, and geological exploration. The germanium crystal of the detector is encapsulated in a vacuum chamber and works in a low-temperature environment. The low-temperature condition is generally achieved by transferring the low temperature from liquid nitrogen in a Dewar flask to the germanium crystal through a cold finger. The vacuum and vacuum interface of the cold finger are sealed by an O-ring. During the long-term use or transportation of the germanium detector, the vacuum sealing performance of the cold finger will deteriorate, and the vacuum degree will decrease, resulting in a vacuum failure of the detector and affecting the performance of the germanium detector. Therefore, it is necessary to improve the vacuum degree of the cold finger through vacuum maintenance to restore the working state and performance indicators of the detector. When dealing with the cold finger of a germanium detector in a vacuum failure, it is necessary to connect the cold finger vacuum to the vacuum maintenance system through a specially designed vacuum interface valve according to the structure of the cold finger.

[0003] Since the structures of the cold fingers and vacuum interfaces of detectors from different manufacturers or germanium detectors produced at different times are different, the vacuum interface valves of the cold fingers need to be designed specifically, so their structures are diverse. At present, there is no relevant report on the vacuum interface valve for the horizontal cold finger of the POPTOP type germanium detector. Similar literature reports on the interface valves of detector vacuum chambers include "Repair System for Neutron Radiation Damaged HPGe Detectors" (Lei Xiangguo et al., Nuclear Electronics & Detection Technology, No. 3, 1996) and "A Vacuum Maintenance System for High-Purity Germanium Detectors with Thermal Purification Function" (CN103728651A, Zhang Xiaolin et al.). In the structure schematic diagram of the HPGe detector repair system in the literature, an interface valve is given, but the composition structure of the interface valve is not discussed. Moreover, in the literature and patent CN103728651A (the first two types), the vacuum interface of the HPGe (high-purity germanium) detector is located on the circular plane at the bottom of the detector vacuum chamber. The vacuum interface sealing plug is a cylindrical structure with an O-ring set in the center, and it is relatively easy to pull out and insert into the vacuum interface. At the same time, fixing screw holes are respectively provided on the circular planes on both sides of the sealing plug during the preparation of the detector. Therefore, the vacuum interface of this type of HPGe (high-purity germanium) detector and the interface valve are plane contact surfaces, and the two are easily fixedly connected through the existing screw holes. The third type in patent CN103728651A is an interface valve for a germanium detector with a thin-wall external vacuum interface. The interface valve is vertically fixed on a fixed base plate, and the fixed base plate is connected to two U-shaped fixing plates through screws for fixation, and centering adjustment is required during installation.

[0004] The present invention has studied the structure of the horizontal cold finger of a germanium detector, that is Figure 1 , Figure 2 the vacuum interface of the detector cold finger shown in the figure. The vacuum interface is a hollow cylinder and is vertically arranged on the circumferential surface of the cold finger sealing and fixing section. The cylindrical vacuum interface is composed of two parts, the upper cylindrical part has a wall thickness of 1 mm, a length of 22.3 mm, and a diameter of 17.4 mm, and the lower cylindrical part has a height of 4.0 mm and a diameter of 13.4 mm. The internal structure of the cylindrical vacuum interface from the outside to the inside is a circlip, a gasket, a spring, a vacuum seal plug, and a vacuum pumping port in sequence. The vacuum pumping port is a hollow truncated cone "flare" structure with a wider upper part and a narrower lower part. The vacuum seal plug is composed of 4 sections. The 1st to 3rd sections from top to bottom are cylinders with diameters of φ11.5 mm × 2.2 mm, φ15.6 mm × 1.6 mm, and φ9.6 mm × 2.4 mm respectively. A circular groove is provided in the 3rd section for placing an O-ring, and a blind hole with a thread depth of 6 mm is provided in the center of the first 3 sections; the 4th section is a frustum with an upper end face diameter of φ10.7 mm, a lower end face diameter of 7 mm, and a height of 2.0 mm. The lower end face has a chamfered structure and matches the end face of the vacuum pumping port frustum. The circlip is fixed in the inner groove along the upper edge of the upper cylinder of the vacuum interface. The circlip compresses the spring through the gasket to make the cold finger vacuum seal plug and the vacuum pumping port closely fit to achieve sealing. Therefore, for the structural characteristics of the horizontal cold finger vacuum interface of the germanium detector shown in Figure 1 , Figure 2 the figure, how to achieve the fixation and sealing of the vacuum interface valve and the vacuum interface, and the convenient opening and closing of the vacuum seal plug are the key contents of the vacuum interface valve design.

[0005] Compared with the above-mentioned existing similar literature and patents, the present invention has the following distinct key technical difficulties in several aspects: (1) The fixing technology of the vacuum interface valve. In the literature and patents, the vacuum interface valve of the detector is fixed to the fixed screw holes provided on the plane contact surface during the preparation of the detector, or the fixed bottom plate of the interface valve is fixed by connecting two U-shaped fixing plates; while the vacuum interface of the cold finger of this patent is a hollow cylindrical shape composed of upper and lower parts and is perpendicular to the cold finger sealing cylindrical fixed section, and the height differences between the upper and lower ends of the cold finger sealing fixed section and the cold finger head on the symmetric side of the vacuum interface are asymmetric, with only a 3-mm height difference at the upper end, so the U-shaped fixing plate is not applicable. Therefore, for the cold finger with the structure of this patent, it is necessary to solve the fixing technology of the vacuum interface valve and the cold finger sealing fixed section on the cylindrical surface; (2) The sealing technology of the vacuum interface valve. In the literature and patents, the contact surface between the vacuum interface valve of the detector and the vacuum sealing plug is a plane structure, and it is easy to achieve the sealing with the vacuum sealing plug through an O-ring or a polytetrafluoroethylene gasket placed in the inner hole of the interface valve. However, the vacuum interface of this patent is a hollow cylindrical structure with a wider upper part and a narrower lower part, the wall thickness is only 1 mm, and the connection between the lower end and the cold finger sealing fixed section is a circular arc surface. Therefore, the O-ring or polytetrafluoroethylene gasket is not applicable to the sealing of the cold finger vacuum interface with the structure of this patent, and it is necessary to study and solve the sealing technology of the vacuum interface valve and the vacuum interface for this patent; (3) The fastening connection technology between the pull rod and the vacuum sealing plug. In the literature and patents, the vacuum sealing plug of the detector realizes the sealing with the vacuum pumping port through an O-ring sleeved in the circular groove in the middle part of the sealing plug. During vacuum maintenance, when the pull rod pulls the vacuum sealing plug to open the vacuum chamber, it does not receive other external forces during the axial movement in the vacuum pumping port and the vacuum interface valve housing. Therefore, the threads matching the end of the pull rod and the blind hole of the vacuum sealing plug only need to be rotated a few turns, and it is not necessary to rotate the two to the bottom. However, the vacuum sealing plug of the cold finger described in this patent can only move in the cylindrical vacuum interface after being pulled by the pull rod, and it will be subjected to the elastic force in the opposite direction of the spring during the whole movement process, and the elastic force increases with the increase of the moving distance. Therefore, the threads of the pull rod and the vacuum sealing plug need to be fastened. Otherwise, during the long-term vacuum maintenance process, the reaction force of the spring elastic force may cause the vacuum sealing plug to fall off from the lower end of the pull rod and block the vacuum pumping port, resulting in the failure of vacuum maintenance. For the cold finger with the structure described in this patent, it is necessary to study and solve the fastening connection technology between the pull rod and the vacuum sealing plug. On the one hand, when the end of the pull rod is screwed into the screw hole of the vacuum sealing plug, the vacuum sealing plug should not rotate synchronously in the vacuum interface, and the end of the pull rod needs to be completely screwed into the screw hole of the vacuum sealing plug; on the other hand, during the process of screwing out the screw hole of the vacuum sealing plug at the end of the pull rod after the vacuum maintenance is completed, the vacuum sealing plug should not rotate in the vacuum interface either, otherwise it will cause the leakage of the vacuum in the cold finger vacuum chamber. (4) The technology to prevent the pull rod from rebounding during vacuum maintenance.The vacuum sealing plug of the detector described in the literature and patents is axially moved in the vacuum pumping port and the vacuum interface valve housing by pulling a pull rod without being affected by other external forces. Therefore, during vacuum maintenance, the pull rod will not rebound. However, for the cold finger described in this patent, when the pull rod pulls the vacuum sealing plug, it can only move a maximum of 4 mm within the cylindrical vacuum interface, and during the pulling process, it always bears the elastic force in the opposite direction of the spring, resulting in the pull rod rebounding during vacuum maintenance, thus causing the vacuum sealing plug to block the vacuum pumping port and leading to the failure of vacuum maintenance. Therefore, for the cold finger with the structure described in this patent, it is necessary to solve the problem of preventing the pull rod from rebounding during vacuum maintenance. Utility Model Content

[0006] In order to overcome the deficiency that the performance index of the horizontal cold finger of the POPTOP type detector deteriorates due to vacuum failure, the present utility model proposes a vacuum interface valve for the horizontal cold finger of a germanium detector of the POPTOP type.

[0007] The technical solution adopted by the present utility model to solve its technical problems is as follows:

[0008] A vacuum interface valve for the horizontal cold finger of a germanium detector of the POPTOP type, comprising a fixing unit, an interface valve unit, and a bottom plate fixing screw.

[0009] The fixing unit includes a fixing ring and a fixing panel. The fixing ring is used to fix the cold finger sealing and fixing section, and the fixing panel is fixedly connected to the interface valve unit through the bottom plate fixing screw.

[0010] The interface valve unit includes a pull rod, an end spring, a fixing bottom plate, a cylindrical sleeve type sealing ring, a housing, a sealing nut, a fixing nut, an O-ring, a handle, and a KF40 interface.

[0011] The pull rod is fixedly connected to the housing through the fixing nut. The fixing bottom plate and the housing are of an integral structure, and the pull rod passes through the fixing bottom plate and the housing.

[0012] The housing is of a hollow structure, provided with an O-ring fixing groove. The O-ring is located in the O-ring fixing groove. The sealing nut is connected to the housing to compress the O-ring. The KF40 interface is connected to the housing for connecting the interface valve to the vacuum maintenance system.

[0013] The fixing bottom plate is provided with a cylindrical sleeve type sealing ring fixing groove. The cylindrical sleeve type sealing ring is located in the cylindrical sleeve type sealing ring fixing groove. The fixing bottom plate is also provided with fixing holes, and the bottom plate fixing screw matches the fixing holes for fixedly connecting the fixing bottom plate and the fixing panel.

[0014] The pull rod sequentially passes through the fixing nut, the sealing nut, the O-ring, the housing, and the fixing base plate. One end of the pull rod is provided with a thread, which matches the blind hole 9 of the cold finger vacuum sealing plug 7. The end spring is located outside the thread and is fixedly welded to the pull rod. The middle upper part of the pull rod is provided with a middle upper section thread, which matches the fixing nut. The cylindrical handle is located at the uppermost end of the pull rod, and the handle is threadedly connected to the pull rod.

[0015] The fixing base plate and the fixing panel are fixedly connected by the base plate fixing screws.

[0016] For the above vacuum interface valve, the diameter of the fixing ring matches the outer diameter of the cold finger sealing and fixing section for fixing the cold finger sealing and fixing section. The fixing ring includes a C-shaped rear fixing ring, a C-shaped front fixing ring, and fixing screws. Both the C-shaped rear fixing ring and the C-shaped front fixing ring are provided with fixing screw holes, and the fixing screws pass through the fixing screw holes, and the C-shaped rear fixing ring and the C-shaped front fixing ring are fixedly connected by the fixing screws.

[0017] The fixing panel and the C-shaped front fixing ring are of an integral structure. The fixing panel is parallel to the center of the circular ring of the fixing ring, and the outer plane is tangent to the outer side of the circular ring of the fixing ring.

[0018] A central hole is provided at the center of the fixing panel, which matches the cylindrical part on the vacuum interface. The diameter of the central hole is larger than the diameter of the cylindrical part on the vacuum interface. The fixing panel is also provided with two threaded holes, which are symmetrically centered relative to the center of the central hole, and the threaded holes are provided with internal threads. The central hole and the threaded holes are used to fix the cylindrical part on the vacuum interface.

[0019] For the above vacuum interface valve, the thickness of the fixing panel is 5 mm, and its outer plane is externally tangent to the circular ring of the fixing ring.

[0020] For the above vacuum interface valve, the diameter of the central hole is 17.8 mm.

[0021] For the above vacuum interface valve, the base plate fixing screws pass through the fixing holes and the threaded holes.

[0022] For the above vacuum interface valve, the length of the middle upper section thread is 8 mm.

[0023] For the above vacuum interface valve, the inner diameter of the cylindrical sleeve-shaped sealing ring is larger than the outer diameter of the central hole.

[0024] The beneficial effects of the present utility model are:

[0025] A vacuum interface valve for a POPTOP-type germanium detector horizontal cold finger, and the fixing unit can realize the fixed connection between the cold finger vacuum interface valve and the circumferential surface of the horizontal cold finger.

[0026] A vacuum interface valve for the horizontal cold finger of a POPTOP-type germanium detector, with a cylindrical sleeve-type sealing ring and a fixing unit built into a fixing groove to achieve the sealing of the vacuum interface valve.

[0027] A vacuum interface valve for the horizontal cold finger of a POPTOP-type germanium detector, where the spring structure at the end of the pull rod can achieve the complete connection and disassembly of the pull rod and the vacuum sealing plug.

[0028] A vacuum interface valve for the horizontal cold finger of a POPTOP-type germanium detector, where the threaded structures in the upper middle section of the fixing nut and the pull rod achieve the firm connection of the pull rod and the vacuum sealing plug, and at the same time can prevent the pull rod from rebounding.

[0029] A vacuum interface valve for the horizontal cold finger of a POPTOP-type germanium detector, which can open and close the vacuum chamber of the cold finger without leaking vacuum, realizing the vacuum maintenance of the cold finger, and can restore the performance indicators of the germanium detector with cold finger vacuum failure. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the horizontal cold finger structure of the germanium detector;

[0031] Figure 2 It is a schematic diagram of the cold finger vacuum interface structure;

[0032] Figure 3 It is a schematic diagram of the fixing unit structure;

[0033] Figure 4 It is a schematic diagram of the interface valve unit structure.

[0034] Reference Numerals: 1. Cold finger tip, 2. Cold finger sealing and fixing section, 3. Cold finger vacuum interface, 4. Snap ring, 5. Gasket, 6. Spring, 7. Vacuum sealing plug, 8. O-ring, 9. Blind hole, 10. Vacuum pumping port; 21. C-type rear fixing ring, 22. C-type front fixing ring, 23. Fixing screw hole, 24. Fixing screw, 25. Fixing panel, 26. Central hole, 27. Threaded hole; 31. Pull rod, 32. Thread, 33. End spring, 34. Fixing bottom plate, 35. Fixing hole, 36. Bottom plate fixing screw, 37. Cylindrical sleeve-type sealing ring fixing groove, 38. Cylindrical sleeve-type sealing ring, 39. Housing, 40. Sealing nut, 41. Fixing nut, 42. O-ring fixing groove, 43. O-ring, 44. Upper middle section thread, 45. Handle, 46. KF40 interface. Detailed Embodiments

[0035] The following further describes the present utility model in detail with reference to the drawings and specific embodiments.

[0036] Embodiment 1

[0037] A vacuum interface valve for the horizontal cold finger of a POPTOP type germanium detector, comprising a fixing unit and an interface valve unit.

[0038] As Figure 3 shown, the fixing unit includes a fixing ring, fixing screw holes 23, fixing screws 24, a fixing panel 25, a central hole 26 and threaded holes 27.

[0039] The fixing ring is composed of a C-shaped rear fixing ring 21 and a C-shaped front fixing ring 22, and the diameter of the fixing ring matches the outer diameter of the cold finger sealing and fixing section 2.

[0040] The fixing panel 25 and the C-shaped front fixing ring 22 are an integral body. The fixing panel 25 is vertically arranged at the center of the circle of the C-shaped front fixing ring 22. The thickness of the fixing panel 25 is 5 mm, and one side plane of it is tangent to the outer circle of the fixing ring. A central hole 26 with a diameter of 17.8 mm is arranged at the center of the fixing panel 25. The diameter of the central hole 26 is slightly larger than the diameter of the cylindrical part 17.4 mm on the vacuum interface, so that the fixing panel 25 can be sleeved on the cylindrical part of the vacuum interface. At this time, the surface of the fixing panel 25 extends beyond the lower cylindrical part of the cylindrical vacuum interface.

[0041] The threaded holes 27 are symmetrically arranged on both sides of the central hole 26, and internal threads are provided in the threaded holes 27.

[0042] The fixing ring is nested outside the cold finger sealing and fixing section 2 through the fixing screws 24 passing through the fixing screw holes 23.

[0043] As Figure 4 shown, the interface valve unit includes a pull rod 31, threads 32, an end spring 33, a fixing bottom plate 34, fixing holes 35, bottom plate fixing screws 36, a cylindrical sleeve type seal ring fixing groove 37, a cylindrical sleeve type seal ring 38, a housing 39, a sealing nut 40, a fixing nut 41, an O-ring fixing groove 42, an O-ring 43, upper and middle section threads 44, a handle 45 and a KF40 interface 46.

[0044] On one side of the top of the pull rod 31, threads 32 matching the blind hole 9 of the cold finger vacuum sealing plug 7 are provided. An end spring 33 is arranged on the outer periphery of the threads 32, and the bottom of the end spring 33 is welded to the pull rod 31 as a whole. Upper and middle section threads 44 are provided in the middle and upper part of the pull rod 31, and the length of the upper and middle section threads 44 is 8 mm. A cylindrical handle 45 is provided at the uppermost end of the pull rod 31, and the handle 45 is connected to the pull rod 31 through a threaded structure.

[0045] The fixing bottom plate 34 and the fixing panel 25 of the fixing unit are of the same size. The fixing holes 35 are symmetrically arranged on both sides of the fixing bottom plate 34 and are through-hole structures. In terms of spatial layout and diameter size, the fixing holes 35 match the threaded holes 27 on the fixing panel 25 of the fixing unit.

[0046] The bottom plate fixing screw 36 passes through the fixing hole 35 and is connected in a matching manner with the threaded hole 27 on the fixing panel 25 of the fixing unit. The through-hole structure of the fixing hole 35 and the threaded structure of the threaded hole 27 are designed to facilitate the operation when the bottom plate fixing screw 36 is connected, thereby realizing the fixation of the vacuum interface valve.

[0047] The cylindrical sleeve type sealing ring fixing groove 37 is arranged at the lower end of the housing 39, and the cylindrical sleeve type sealing ring 38 is placed in the fixing groove 37. Its lower bottom surface is exposed outside the fixing groove 37, and the inner diameter is larger than the outer diameter of the central hole 26 of the fixing unit. The vacuum interface valve is connected to the fixing unit by the bottom plate fixing screw 36 to compress the sealing ring 38, thereby realizing the sealing of the vacuum interface valve.

[0048] The housing 39 is a hollow structure that is thicker at the bottom and thinner at the top. The lower end is used to place the cylindrical sleeve type sealing ring 38, so it has a larger diameter, and the upper end is used for the axial movement of the pull rod 31, so it has a slightly smaller diameter.

[0049] The thread of the sealing nut 40 is structurally matched with the thread at the upper end of the housing 39. A hole is provided at the center of the bottom surface of the sealing nut 40, and the diameter of the hole is matched with the outer diameter of the pull rod 31.

[0050] The fixing nut 41 is an integral structure composed of two sections. The lower section is a cylindrical through-hole structure, and its inner diameter is larger than the outer diameter of the pull rod 31. A hole is provided at the center of the bottom surface of the upper section nut, and a thread is provided in the hole, and the thread is matched with the middle and upper section thread 44 of the pull rod 31.

[0051] The O-ring fixing groove 42 is sleeved on the pull rod 31, and the O-ring 43 is placed in the O-ring fixing groove 42.

[0052] The pull rod 31 sequentially passes through the fixing nut 40, the sealing nut 41, the O-ring fixing groove 42, the O-ring 43, the upper end and the hollow section of the housing 39 until the thread 32 of the pull rod 31 extends out of the housing fixing base plate 34. Then, install the pull rod handle 45 and screw in the sealing nut 40. By fixing with the thread at the top of the housing 39, the sealing nut 40 presses the O-ring 43 tightly to achieve the sealing between the pull rod 31 and the housing 39. The lower thick section of the housing 39 is sleeved outside the cylindrical cold finger vacuum interface, so that the threaded top of the pull rod 31 fits with the surface of the blind hole 9 of the vacuum sealing plug 7. Screw the fixing nut 41 into the middle upper section thread 44 of the pull rod 31 until the lower section of the fixing nut 41 is closely tangent to the bottom surface of the sealing nut 40. At this time, 6 mm of the middle upper section thread 44 of the pull rod 31 is exposed outside the bottom surface of the fixing nut 41. Screw the pull rod 31 inward so that the top thread 32 of the pull rod 31 is threadedly connected to the blind hole 9 of the vacuum sealing plug 7. During the screwing-in process, the force of the end spring 33 of the pull rod 31 pressing down on the vacuum sealing plug 7 gradually increases, which can prevent the vacuum sealing plug 7 from rotating in the vacuum interface 10; until all the exposed 6 mm of the middle upper section thread 44 is screwed into the bottom surface of the fixing nut 41. At this time, the top thread 32 of the pull rod 31 is completely screwed into the bottom of the blind hole 9 of the vacuum sealing plug 7, realizing the fastening connection between the pull rod 31 and the vacuum sealing plug 7; when pulling the pull rod 31 outward, first loosen the fixing nut 41 and move it near the handle 45. The pull rod 31 will pull the vacuum sealing plug 7 to move in the cylindrical vacuum interface. Until it is difficult to pull the pull rod 31 outward, in this case, the maximum distance that the pull rod 31 pulls the vacuum sealing plug 7 to move in the cylindrical vacuum interface is 4 mm, and during the entire pulling process, the vacuum sealing plug 7 will always be subject to the reaction force of the spring 6 in the opposite direction of the movement. At this time, screw the fixing nut 41 towards the sealing nut 40 until they fit. At this time, 4 mm of the 8 mm long middle upper section thread 44 of the pull rod 31 is screwed out of the bottom surface of the fixing nut 41. Through the threaded connection structure between the two, it can prevent the pull rod 31 from pulling the vacuum sealing plug 7 to open the cold finger vacuum chamber from rebounding during vacuum maintenance. When closing the cold finger vacuum chamber, screw the pull rod 31 inward until all the 4 mm screws of the pull rod 31 exposed outside the bottom surface of the fixing nut 41 are screwed in. At this time, the vacuum sealing plug 7 completely seals the vacuum pumping port 10; then loosen the fixing nut 41 and move it near the handle 45, and then rotate the pull rod 31 in the opposite direction to disassemble the pull rod 31. During the disassembly process, under the combined elastic force of the end spring 33 of the pull rod 31 upward and the vacuum interface spring 6 downward, it can prevent the vacuum sealing plug 7 from rotating in the vacuum interface and causing vacuum leakage of the cold finger vacuum chamber.

[0053] KF40 interface 46 is used for connecting the interface valve and the vacuum maintenance system.

[0054] Embodiment 2

[0055] A vacuum interface valve for the horizontal cold finger of a POPTOP-type germanium detector, working process:

[0056] Step 1: As Figure 1 , Figure 3 shown, put the central hole 26 of the C-type front fixing ring 23 over the vacuum interface 3 of the cold finger. The C-type front fixing ring 23 is externally tangent to the cold finger sealing and fixing section 2. Connect the C-type rear fixing ring 21 and the C-type front fixing ring 23 through the fixing screw 24 passing through the fixing screw hole 23. The structural design of the central hole 26 of the C-type front fixing ring 23 and the fixing screw 24 realizes the positioning and fixing of the fixing ring;

[0057] Step 2: As Figure 4 shown, after removing the handle 45 from the pull rod 31, pass the pull rod 31 through the central hole of the fixed bottom plate 34 at the lower end of the housing until it is exposed at the other end of the housing 39. Then, successively put the O-ring 43, the O-ring fixing groove 42, the sealing nut 40, and the fixing nut 41 on the pull rod 31, and then install the handle 45;

[0058] Step 3: As Figure 4 , Figure 1 , Figure 3 and Figure 2 shown, completely put the housing 39 over the cold finger vacuum interface 3, and pass the bottom plate fixing screw 36 through the fixing hole 35 and tighten it into the threaded hole 27; after completing Process 1, there is only a 5-mm gap between the lower surface of the fixed panel 25 and the cold finger sealing and fixing section 2. It is very difficult to complete the connection operation of the fixing screw 36 from the bottom (threaded hole 27) to the top (fixing hole 35). Therefore, the through-hole structure of the fixing hole 35 and the threaded structure of the threaded hole 27 are designed to facilitate the operation when the bottom plate fixing screw 36 is connected from the top (through the fixing hole 35) to the bottom (screwing into the threaded hole 27), realizing the fixed connection between the vacuum interface valve fixed bottom plate 34 and the fixed panel 25; at the same time, after completing Step 1, the thickness and structure of the fixed panel 25 are designed so that the upper surface of the fixed panel 25 is higher than the thinner lower cylindrical part of the cold finger vacuum interface 3, that is, it is flush with the thicker upper cylindrical part of the vacuum interface 3. At the same time, the design of the difference in diameter between the cylindrical sleeve-type sealing ring 38 and the central hole 26, so the sealing between the interface valve fixed bottom plate 34 and the fixed panel 25 can be realized by pressing the cylindrical sleeve-type sealing ring 38 placed in the cylindrical sleeve-type sealing ring fixing groove 37.

[0059] Step 4: As Figure 4 , Figure 2As shown, the sealing nut 40 is screwed tightly onto the upper end of the housing 39, and the pull rod 31 is screwed into the housing 39 for adjustment so that the top thread 32 of the pull rod is tangent to the surface of the blind hole 9 of the vacuum sealing plug 7. The fixing nut 41 is screwed into the middle and upper section thread 44 of the pull rod until the lower section of the fixing nut 41 is closely tangent to the bottom surface of the sealing nut 40. At this time, 6 mm of the middle and upper section thread 44 of the pull rod is exposed outside the bottom surface of the fixing nut 41. Continue to screw the pull rod 31 inward so that the top thread 32 of the pull rod 31 is threadedly connected to the blind hole 9 of the vacuum sealing plug 7. During the screwing-in process, the force of the end spring 33 of the pull rod 31 pressing down on the vacuum sealing plug 7 increases, which can prevent the vacuum sealing plug 7 from rotating in the vacuum interface 3; until all 6 mm of the exposed middle and upper section thread 44 is screwed into the bottom surface of the fixing nut 41. At this time, the thread 32 at the top of the pull rod 31 is completely screwed into the bottom of the blind hole 9 of the vacuum sealing plug 7, realizing the fastening connection between the pull rod 31 and the vacuum sealing plug 7.

[0060] Step 5: As Figure 4 , Figure 2 shown, loosen the fixing nut 41 and move it near the handle 45, then pull the pull rod 31 outward. The vacuum sealing plug 7 firmly connected to the pull rod 31 moves within the cylindrical vacuum interface 3 until it is difficult to pull the pull rod 31 outward. In this case, the maximum distance that the pull rod 31 pulls the vacuum sealing plug 7 to move within the cylindrical vacuum interface 3 is 4 mm, and throughout the pulling process, the vacuum sealing plug 7 will always be subject to the reaction force of the spring 6 in the opposite direction of the movement. At this time, screw the fixing nut 40 towards the sealing nut 41 until they fit together. 4 mm of the 8 mm long middle and upper section thread 44 of the pull rod 31 protrudes from the bottom surface of the fixing nut 41. Through the design of the threaded connection structure between the two, it can prevent the pull rod 31 from pulling the vacuum sealing plug 7 to open the cold finger vacuum chamber and causing the failure of vacuum maintenance due to rebound during vacuum maintenance. Connect to the vacuum maintenance system through the KF40 interface 46 to perform long-term vacuum maintenance on the cold finger.

[0061] Step 6: As Figure 4 , Figure 2 shown, after the cold finger vacuum maintenance is completed, screw the pull rod 31 inward until all 4 mm of the screw of the pull rod 31 exposed outside the bottom surface of the fixing nut 41 is screwed in. At this time, the vacuum sealing plug 7 completely seals the vacuum pumping port 10, realizing the closing of the cold finger vacuum chamber.

[0062] Step 7: As Figure 4 , Figure 2 shown, loosen the fixing nut 41 and move it near the handle 45, then rotate the pull rod 31 in the opposite direction to disassemble the pull rod 31. During the disassembly process, under the combined elastic force of the end spring 33 of the pull rod 31 upward and the vacuum interface spring 6 downward, it can prevent the vacuum sealing plug 7 from rotating in the vacuum interface 10 and causing vacuum leakage in the cold finger vacuum chamber.

[0063] Step 8: Thoroughly cool the detector, and then conduct performance index tests.

Claims

1. A vacuum interface valve for horizontal cold finger of POPTOP type germanium detector, characterized in that: It includes a fixing unit, an interface valve unit, and bottom plate fixing screws (36); in: The fixing unit comprises a fixing ring and a fixing panel (25), wherein the fixing ring is used to fix the cold finger seal fixing section (2); the interface valve unit comprises a pull rod (31), an end spring (33), a fixing base plate (34), a cylindrical sleeve type sealing ring (38), a housing (39), a sealing nut (40), a fixing nut (41), an O-ring (43), a handle (45), and a KF40 interface (46); The pull rod (31) and the housing (39) are fixedly connected via a fixing nut (41); the fixed bottom plate (34) and the housing (39) are an integral structure; the pull rod (31) passes through the fixed bottom plate (34) and the housing (39); The housing (39) is a hollow structure, and is provided with an O-ring fixing groove (42). The O-ring (43) is located in the O-ring fixing groove (42). The sealing nut (40) is connected to the housing (39) and is used to compress the O-ring (43). The KF40 interface (46) is connected to the housing (39) and is used to connect the interface valve to the vacuum maintenance system. The fixed bottom plate (34) is provided with a cylindrical sleeve-shaped sealing ring fixing groove (37), and the cylindrical sleeve-shaped sealing ring (38) is located in the cylindrical sleeve-shaped sealing ring fixing groove (37); the fixed bottom plate (34) is also provided with a fixing hole (35), and the bottom plate fixing screw (36) matches the fixing hole (35) and is used to fix the bottom plate (34) and the fixed panel (25) to be fixedly connected; The pull rod (31) passes through the fixing nut (41), the sealing nut (40), the O-ring (43), the shell (39), and the fixed base plate (34) in sequence; a thread (32) is provided at one end of the pull rod (31), the thread (32) matches the blind hole (9) of the cold finger vacuum sealing plug (7), the end spring (33) is located outside the thread (32), and the end spring (33) is welded and fixed to the pull rod (31); a middle and upper section thread (44) is provided at the middle and upper part of the pull rod (31), and the middle and upper section thread (44) matches the fixing nut (41); a cylindrical handle (45) is located at the uppermost end of the pull rod (31), and the handle (45) is connected to the pull rod (31) by a thread; The fixed bottom plate (34) and the fixed panel (25) are connected and fixed via bottom plate fixing screws (36).

2. The vacuum interface valve according to claim 1, characterized in that: The diameter of the fixing ring matches the outer diameter of the cold finger seal fixing section (2) and is used to fix the cold finger seal fixing section (2); the fixing ring comprises a C-type rear fixing ring (21), a C-type front fixing ring (22), and a fixing screw (24); the C-type rear fixing ring (21) and the C-type front fixing ring (22) are both provided with fixing screw holes (23), the fixing screws (24) pass through the fixing screw holes (23), and the C-type rear fixing ring (21) and the C-type front fixing ring (22) are connected and fixed by the fixing screws (24); The fixed panel (25) is connected to the C-shaped front fixed ring (22), the fixed panel (25) is parallel to the center of the fixed ring, and the outer plane is tangent to the outer side of the fixed ring; A central hole (26) is arranged at the center of the fixed panel (25), the central hole (26) matches the cylindrical portion on the vacuum interface, and the diameter of the central hole (26) is larger than the diameter of the cylindrical portion on the vacuum interface; the fixed panel (25) is also provided with two thread holes (27), the two thread holes (27) are symmetrical relative to the center of the central hole (26), and the thread holes (27) are provided with internal threads; the central hole (26) and the thread holes (27) are used to fix the cylindrical portion on the vacuum interface.

3. The vacuum interface valve according to claim 2, characterized in that: The thickness of the fixed panel (25) is 5 mm, and its outer plane is circumscribed to the fixed ring.

4. The vacuum interface valve according to claim 2, characterized in that: The diameter of the central hole (26) is 17.8 mm.

5. The vacuum interface valve according to claim 2, characterized in that: The bottom plate fixing screw (36) passes through the fixing hole (35) and the thread hole (27).

6. The vacuum interface valve according to claim 1, characterized in that: The length of the middle and upper thread (44) is 8 mm.

7. The vacuum interface valve according to claim 1, characterized in that: The inner diameter of the cylindrical sleeve-shaped sealing ring (38) is greater than the outer diameter of the central hole (26).

8. The vacuum interface valve according to claim 2, characterized in that: The fixed panel (25) and the C-shaped front fixed ring (22) are an integral structure.

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