Low-temperature vacuum device for dark current and low background test of infrared detector

Abstract

The invention relates to the technical field of infrared detection, in particular to a low-temperature vacuum device for dark current and low background test of an infrared detector, which comprises a secondary pulse tube refrigerator, a shell assembly, a support assembly and a detection assembly, a second-stage pulse tube refrigerator room temperature flange is connected to the outer circle fixing end of the top of a compressor of the second-stage pulse tube refrigerator, a linear refrigerator is arranged at the top of the shell assembly, the bottom of the cold finger extends into the shell assembly and is used for fixing a low-temperature blackbody radiation blackboard, and an indium piece is arranged between the bottom of the cold finger and the low-temperature blackbody radiation blackboard in a cushioned mode. The supporting assembly is arranged in the shell assembly, a low-temperature air suction box is arranged in the supporting assembly, the detection assembly is arranged in the supporting assembly, and the top of the detection assembly is used for placing a detector; the weak energy radiation test requirements can be fully met.

Description

Technical Field

[0001] The present invention relates to the field of infrared detection technology, and more particularly, to a cryogenic vacuum device for dark current and low background testing of infrared detectors. Background Art

[0002] Hyperspectral imaging technology integrates imaging and spectroscopy. With a high spectral resolution at the nanometer level, while obtaining the two-dimensional spatial image information of the target, it simultaneously obtains the continuous and fine spectral information of the target, greatly improving the detection ability of space remote sensing. Compared with visible, near-infrared, and short-wave infrared, the mid-wave and long-wave infrared hyperspectral imaging technology in the range of 5.0 μm to 15 μm has unique advantages. The spectral coverage range reaches nearly ten thousand nanometers, and it can obtain the fine spectral information of the thermal radiation of the target itself. It can not only effectively identify the composition of ground objects, but also effectively distinguish the structural characteristics of ground objects, and obtain parameter information such as the temperature and emissivity of ground objects, and can be widely used in observations of land, atmosphere, ocean, etc. The equivalent blackbody temperature value with a peak wavelength in the mid-wave and long-wave infrared spectral range of 5.0 - 12.5 μm is in the range of 240 - 370 K (-33 °C - 97 °C). This temperature range includes the vast majority of objects on the earth's surface, that is, almost all objects can radiate energy in this wavelength band range. Therefore, the mid-wave and long-wave infrared hyperspectral imager is seriously affected by background radiation stray light. The cold optical technology places the optical elements and detectors of the infrared optical system in the rear optical path assembly, and reduces the temperature of the optical elements and detectors to the operating temperature through a deep cryogenic energy source, thereby effectively suppressing the influence of the thermal radiation and stray light of the optical elements and their support structures on the detection performance, and minimizing the background noise to the greatest extent. Under this background, the infrared detectors applied need to simulate their performance evaluation under low-temperature background energy irradiation (the equivalent blackbody radiation blackboard temperature is below 220 K) during delivery testing. The traditional national standard infrared detector test system and test method cannot correctly evaluate the performance of the detector under weak signal illumination. There is an urgent need for a cryogenic vacuum test device for screening the performance of infrared detectors with low background detection to solve this problem. Summary of the Invention

[0003] In view of this, in view of the deficiencies of the prior art, the present invention provides a cryogenic vacuum device for dark current and low background testing of infrared detectors, aiming to solve at least one of the problems raised in the above background art.

[0004] The present invention provides a cryogenic vacuum device for dark current and low background testing of infrared detectors, including: a two-stage pulse tube refrigerator, and the outer circumferential fixed end of the compressor top of the two-stage pulse tube refrigerator is connected with a two-stage pulse tube refrigerator room temperature flange;

[0005] A housing assembly, the bottom of the housing assembly is fixedly and sealingly connected to the room temperature flange of the second-stage pulse tube refrigerator through bolts, a linear refrigerator is provided at the top of the housing assembly, the cold finger of the linear refrigerator is fixedly connected to the top of the housing assembly through a mounting seat, the bottom of the cold finger extends into the interior of the housing assembly, the bottom of the cold finger is used to fix a low-temperature blackbody radiation blackboard, and an indium sheet is padded between the cold finger and the low-temperature blackbody radiation blackboard;

[0006] A support assembly, the support assembly is arranged inside the housing assembly, and the bottom of the support assembly is fixedly connected to the room temperature flange of the second-stage pulse tube refrigerator, and a low-temperature suction box is arranged inside the support assembly;

[0007] A detection assembly, the detection assembly is arranged inside the support assembly, and the top of the detection assembly is used to place a detector.

[0008] In some embodiments, the housing assembly includes:

[0009] A primary housing, the primary housing is arranged on the top of the room temperature flange of the second-stage pulse tube refrigerator, and the bottom of the primary housing is fixedly and sealingly connected to the room temperature flange of the second-stage pulse tube refrigerator through a rubber ring and bolts. Two connection holes are symmetrically arranged on both side walls of the top of the primary housing, and two connection components are arranged on both side walls of the top of the primary housing corresponding to the two connection holes;

[0010] A secondary housing, the secondary housing is arranged on the top of the primary housing, and the bottom of the secondary housing is fixedly and sealingly connected to the top of the primary housing through a rubber ring and bolts. A vacuum valve seat for evacuating the interior of the housing assembly is welded on the outer side wall of the secondary housing, and a vacuum valve plug is installed on the vacuum valve seat;

[0011] A low-temperature blackbody housing, the low-temperature blackbody housing is arranged on the top of the secondary housing, and the bottom of the low-temperature blackbody housing is fixedly and sealingly connected to the top of the secondary housing through a rubber ring and bolts. The installation end of the linear refrigerator is fixedly connected to the top of the low-temperature blackbody housing. A through hole is arranged on the top of the low-temperature blackbody housing corresponding to the mounting seat. The bottom of the mounting seat is fixedly and sealingly connected to the top of the low-temperature blackbody housing. The side wall of the cold finger is fixedly connected to the mounting seat, and the bottom of the cold finger extends downward through the through hole into the interior of the low-temperature blackbody housing.

[0012] In some embodiments, the central axes of the room temperature flange of the second-stage pulse tube refrigerator, the primary housing, the secondary housing, the low-temperature blackbody housing, the mounting seat, the detector, and the through hole coincide, and the axial cross-sections of the primary housing, the secondary housing, and the low-temperature blackbody housing are all in an I-shaped structure.

[0013] In some embodiments, the connection assembly includes:

[0014] A connection box, the top of which is fixedly connected to the side wall of the top of the primary housing, and a connector is provided on a side of the connection box away from the primary housing;

[0015] A penetration plate, wherein the penetration plate is clamped inside the connecting hole, the outer diameter of the penetration plate matches the inner diameter of the connecting hole, a threading hole is provided on the penetration plate, and the penetration plate and the inside of the connecting box are sealedly connected to the secondary housing by glue injection.

[0016] In some embodiments, the low-temperature blackbody radiation blackboard is made of aluminum alloy material, the bottom surface of the low-temperature blackbody radiation blackboard is provided with triangular end face threads, the bottom surface of the low-temperature blackbody radiation blackboard is blackened by graphene spraying, and the top surface of the low-temperature blackbody radiation blackboard is covered with radiation-proof aluminum film.

[0017] In some embodiments, the support assembly comprises:

[0018] The first cylinders are provided with three of them, the three first cylinders are vertically arranged on the top of the room temperature flange of the secondary pulse tube refrigerator, and the bottoms of the three first cylinders are fixedly connected to the top of the room temperature flange of the secondary pulse tube refrigerator, and the outer surfaces of the three first cylinders which are more than 3mm-5mm away from the room temperature flange of the secondary pulse tube refrigerator are covered with multiple layers of radiation-resistant layers;

[0019] A primary cold platform of a secondary pulse tube refrigerator, wherein the primary cold platform of the secondary pulse tube refrigerator is arranged on the top of the three first cylinders, the bottom of the primary cold platform of the secondary pulse tube refrigerator is fixedly connected to the top of the three first cylinders, a lead perforated disk is fixedly connected to the primary cold platform of the secondary pulse tube refrigerator, and the transverse cross section of the lead perforated disk is an annular structure, the low temperature suction box is arranged on the top of the primary cold platform of the secondary pulse tube refrigerator, and the low temperature suction box is arranged on the inner side of the lead perforated disk;

[0020] The second cylinder is provided with two, the two second cylinders are vertically and eccentrically arranged on the top of the first-stage cold platform of the second-stage pulse tube refrigerator, the bottoms of the two second cylinders are fixedly connected to the top of the first-stage cold platform of the second-stage pulse tube refrigerator, the two second cylinders are arranged on the inner side of the lead perforated disk, and the outer surfaces of the two second cylinders which are more than 3mm-5mm away from the first-stage cold platform of the second-stage pulse tube refrigerator are covered with multiple layers of radiation-resistant layers;

[0021] The second-stage cold platform of the two-stage pulse tube refrigerator is arranged on the tops of the two second cylinders, and the tops of the two second cylinders are fixedly connected to the bottom of the second-stage cold platform of the two-stage pulse tube refrigerator. The detection component is arranged on the top of the second-stage cold platform of the two-stage pulse tube refrigerator.

[0022] In some embodiments, the support component further includes:

[0023] The first-stage radiation shield, which is made of stainless steel material, is arranged on the top of the first-stage cold platform of the two-stage pulse tube refrigerator. The low-temperature suction box, the second cylinder, and the lead perforation disk are all arranged inside the first-stage radiation shield. The bottom of the first-stage radiation shield is fixedly connected to the top of the first-stage cold platform of the two-stage pulse tube refrigerator by bolts;

[0024] The second-stage radiation shield, which is made of stainless steel material, is arranged on the top of the first-stage radiation shield. The top of the first-stage radiation shield is fixedly connected to the bottom of the second-stage radiation shield. The inner diameter of the second-stage radiation shield matches the inner diameter of the first-stage radiation shield. A first opening for the cold finger to pass through is arranged on the top of the second-stage radiation shield, and the inner diameter of the first opening is larger than the outer diameter of the low-temperature blackbody radiation blackboard;

[0025] The detector cold shield, whose outer diameter is smaller than the inner diameter of the second-stage radiation shield and whose height is smaller than the height of the second-stage radiation shield, is made of aluminum alloy material. The outer sidewall of the detector cold shield is covered with an anti-radiation layer, and the inner sidewall of the detector cold shield is blackened by sandblasting. One detection hole is opened on the top of the detector cold shield, and the diameter of the detection hole is smaller than the diameter of the low-temperature blackbody radiation blackboard. The top surface of the detector cold shield is blackened by sandblasting, and the bottom of the detector cold shield is fixedly connected to the top of the second-stage cold platform of the two-stage pulse tube refrigerator by bolts.

[0026] In some embodiments, the detection component includes:

[0027] The detector substrate, which is arranged on the top of the second-stage cold platform of the two-stage pulse tube refrigerator, is an alumina ceramic substrate or a aluminum nitride ceramic substrate. The bottom of the detector is adhesively connected to the top of the detector substrate by low-temperature glue, and the detector substrate and the detector are connected by wire bonding;

[0028] Substrate pressing block, the transverse cross-section of the substrate pressing block is an annular structure, the substrate pressing block is arranged on the top of the detector substrate, the substrate pressing block is in contact with the detector substrate, the substrate pressing block is fixedly connected to the second-stage cold platform of the two-stage pulse tube refrigerator through bolts, the bottom of the detector substrate is tightly attached to the top of the second-stage cold platform of the two-stage pulse tube refrigerator through the extrusion of the substrate pressing block, and an indium sheet is padded between the detector substrate and the second-stage cold platform of the two-stage pulse tube refrigerator;

[0029] Electrode pin plate, the electrode pin plate is arranged on the top of the second-stage cold platform of the two-stage pulse tube refrigerator, an indium sheet is padded between the electrode pin plate and the second-stage cold platform of the two-stage pulse tube refrigerator, and the substrate pressing block is located inside the electrode pin plate. The motor pin plate is electrically connected to the connector through a wire passing through the lead perforation plate and the wire passing hole in sequence, and the electrode pin plate is electrically connected to the detector through a lead.

[0030] In some embodiments, the low-temperature suction box includes:

[0031] Box body, the bottom of the box body is fixedly connected to the top of the first-stage cold platform of the two-stage pulse tube refrigerator, an indium sheet is padded between the box body and the first-stage cold platform of the two-stage pulse tube refrigerator, and columnar activated carbon is placed inside the box body;

[0032] Box cover, the box cover is arranged on the top of the box body, and a plurality of air outlet holes are arranged on the top of the box cover. The inner diameter of the air outlet holes is smaller than the outer diameter of the columnar activated carbon, and the box cover is fixedly connected to the box body.

[0033] In some embodiments, both the box body and the box cover are made of aluminum alloy.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-temperature blackbody radiation blackboard of the present invention uses a linear refrigerator for refrigeration, the temperature control accuracy can reach 0.1K, with high accuracy, and the temperature control range is 60K - 300K, which can meet a wide range of weak energy radiation. The surface of the low-temperature blackbody radiation blackboard of the present invention is made with microstructures and a blackening coating, with a high emissivity. The present invention uses a two-stage pulse tube refrigerator, and the detector is installed on the second-stage cold platform of the two-stage pulse tube refrigerator, and the temperature that can be obtained is 4K - 80K, which is suitable for the deep low temperature required by various detectors such as mercury cadmium telluride, type-II detectors, quantum wells, and BIB. The present invention is suitable for the screening test of weak energy detectors, and is also suitable for the tests of detector dark current, linearity, etc., with diverse functions. The interior of the present invention is treated with multiple radiation screens, radiation-resistant layers, etc., greatly reducing the radiant heat, and the power consumption required by the present invention is low. The present invention has a vacuum holding function, and no external vacuum exhaust equipment is required during the test, and the operation is simple and convenient.

[0035] The above general description and the following detailed description are merely exemplary and explanatory, and do not limit the present disclosure.

[0036] Other features and aspects of the present disclosure will become clearer from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Brief Description of the Drawings

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 Isometric sectional view of the cryogenic vacuum device for dark current and low background testing of an infrared detector provided by an embodiment of the present invention;

[0039] Figure 2 Isometric sectional view of the cryogenic vacuum device for dark current and low background testing of an infrared detector provided by an embodiment of the present invention;

[0040] Figure 3 Partial enlarged view of the cryogenic vacuum device for dark current and low background testing of an infrared detector provided by an embodiment of the present invention;

[0041] Figure 4 Isometric view of the cryogenic getter box of the cryogenic vacuum device for dark current and low background testing of an infrared detector provided by an embodiment of the present invention.

[0042] Wherein: 1. Second-stage pulse tube refrigerator; 2. Room temperature flange of the second-stage pulse tube refrigerator; 3. Linear refrigerator; 4. Cold finger; 5. Cryogenic blackbody radiation blackboard; 6. Cryogenic getter box; 7. Detector; 8. Primary housing; 9. Connection hole; 10. Cryogenic blackbody housing; 11. Through hole; 12. Connection box; 13. Connector; 14. Wall-penetrating plate; 15. Wire-passing hole; 16. First cylinder; 17. First-stage cold platform of the second-stage pulse tube refrigerator; 18. Lead-passing perforated disk; 19. Second cylinder; 20. Second-stage cold platform of the second-stage pulse tube refrigerator; 21. First-stage radiation shield; 22. Second-stage radiation shield; 23. First opening; 24. Detector cold shield; 25. Detector substrate; 26. Substrate pressing block; 27. Electrode pin disk; 28. Box body; 29. Box cover; 30. Mounting seat; 31. Secondary housing; 32. Air outlet hole. Detailed Embodiments

[0043] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0044] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0045] The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "plurality" is two or more.

[0046] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0047] Refer to Figures 1-4 As shown, a cryogenic vacuum device for infrared detector dark current and low-background testing according to an embodiment of the present application includes:

[0048] A two-stage pulse tube refrigerator 1, and the fixed end of the outer circle at the top of the compressor of the two-stage pulse tube refrigerator 1 is connected to a two-stage pulse tube refrigerator room-temperature flange 2;

[0049] A housing assembly, the bottom of the housing assembly is fixedly and hermetically connected to the two-stage pulse tube refrigerator room-temperature flange 2 by bolts, a linear refrigerator 3 is provided at the top of the housing assembly, the cold finger 4 of the linear refrigerator 3 is fixedly connected to the top of the housing assembly through a mounting seat 30, the bottom of the cold finger 4 extends into the interior of the housing assembly, and the bottom of the cold finger 4 is used to fix a cryogenic blackbody radiation blackboard 5, and an indium sheet is padded between the cold finger 4 and the cryogenic blackbody radiation blackboard 5;

[0050] A support component is arranged inside the housing component, and the bottom of the support component is fixedly connected to the room-temperature flange 2 of the two-stage pulse tube refrigerator. A low-temperature suction box 6 is arranged inside the support component.

[0051] A detection component is arranged inside the support component, and the top of the detection component is used to place a detector 7.

[0052] In some specific embodiments, the housing component includes:

[0053] A first-stage housing 8 is arranged on the top of the room-temperature flange 2 of the two-stage pulse tube refrigerator, and the bottom of the first-stage housing 8 is fixedly and hermetically connected to the room-temperature flange 2 of the two-stage pulse tube refrigerator through a rubber ring and bolts. Two connection holes 9 are symmetrically arranged on the two side walls at the top of the first-stage housing 8, and two connection components are arranged on the two side walls at the top of the first-stage housing 8 corresponding to the two connection holes 9.

[0054] A second-stage housing 31 is arranged on the top of the first-stage housing 8, and the bottom of the second-stage housing 31 is fixedly and hermetically connected to the top of the first-stage housing 8 through a rubber ring and bolts. A vacuum valve seat for evacuating the inside of the housing component is welded on the outer side wall of the second-stage housing 31, and a vacuum valve plug is installed on the vacuum valve seat.

[0055] A low-temperature blackbody housing 10 is arranged on the top of the second-stage housing 31, and the bottom of the low-temperature blackbody housing 10 is fixedly and hermetically connected to the top of the second-stage housing 31 through a rubber ring and bolts. The installation end of the linear refrigerator 3 is fixedly connected to the top of the low-temperature blackbody housing 10. A through hole 11 is arranged on the top of the low-temperature blackbody housing 10 corresponding to the mounting seat 30. The bottom of the mounting seat is fixedly and hermetically connected to the top of the low-temperature blackbody housing 10. The side wall of the cold finger 4 is fixedly connected to the mounting seat 30, and the bottom of the cold finger 4 extends downward through the through hole 11 into the inside of the low-temperature blackbody housing 10.

[0056] In some specific embodiments, the central axes of the room-temperature flange 2 of the two-stage pulse tube refrigerator, the first-stage housing 8, the second-stage housing 31, the low-temperature blackbody housing 10, the mounting seat 30, the detector 7, and the through hole 11 coincide. The axial cross-sections of the first-stage housing 8, the second-stage housing 31, and the low-temperature blackbody housing 10 are all in an I-shaped structure.

[0057] It should be understood that the inner surfaces of the first-stage housing 8, the second-stage housing 31, and the low-temperature blackbody housing 10 are electrochemically polished.

[0058] In some specific embodiments, the connection component includes:

[0059] A connection box 12, the top of the connection box 12 is fixedly connected to the side wall at the top of the first-stage housing 8, and a connector 13 is arranged on the side of the connection box 12 away from the first-stage housing 8.

[0060] The wall-penetrating board 14 is snap-fitted inside the connection hole 9. The outer diameter of the wall-penetrating board 14 matches the inner diameter of the connection hole 9. A wire-passing hole 15 is provided on the wall-penetrating board 14. The inside of the wall-penetrating board 14 and the connection box 12 are hermetically connected by pouring glue to achieve the sealing connection between the wall-penetrating board 14 and the secondary housing 31.

[0061] It should be understood that the sealing connection between the wall-penetrating board 14 and the secondary housing 31 is achieved by pouring glue to ensure the airtightness inside the housing assembly. After installation, vacuum leak detection is required, and the leak rate requirement is less than 1.5×10 -11 Pa·m3 / S.

[0062] In some specific embodiments, the low-temperature blackbody radiation blackboard 5 is made of aluminum alloy material. A triangular end thread is provided on the bottom surface of the low-temperature blackbody radiation blackboard 5. The bottom surface of the low-temperature blackbody radiation blackboard 5 is blackened by graphene spraying. An anti-radiation aluminum film is covered on the top surface of the low-temperature blackbody radiation blackboard 5.

[0063] It should be understood that the high infrared emissivity of the surface of the low-temperature blackbody radiation blackboard is achieved by graphene spraying. Two temperature-measuring diodes are arranged on the back of the low-temperature blackbody radiation blackboard 5. One is used for temperature control drive of the linear refrigerator 3, and the other is used for temperature measurement and monitoring of the low-temperature blackbody radiation blackboard 5.

[0064] In some specific embodiments, the support assembly includes:

[0065] The first cylinders 16, there are three of them. The three first cylinders 16 are all vertically arranged on the top of the room-temperature flange 2 of the secondary pulse tube refrigerator, and the bottoms of the three first cylinders 16 are fixedly connected to the top of the room-temperature flange 2 of the secondary pulse tube refrigerator. The outer surfaces of the three first cylinders 16 more than 3 mm - 5 mm away from the room-temperature flange 2 of the secondary pulse tube refrigerator are covered with multiple anti-radiation layers;

[0066] The first-stage cold platform 17 of the secondary pulse tube refrigerator. The first-stage cold platform 17 of the secondary pulse tube refrigerator is arranged on the top of the three first cylinders 16. The bottom of the first-stage cold platform 17 of the secondary pulse tube refrigerator is fixedly connected to the top of the three first cylinders 16. A lead-passing perforated disc 18 is fixedly connected to the first-stage cold platform 17 of the secondary pulse tube refrigerator. The transverse section of the lead-passing perforated disc 18 is an annular structure. The low-temperature suction box 6 is arranged on the top of the first-stage cold platform 17 of the secondary pulse tube refrigerator, and the low-temperature suction box 6 is arranged inside the lead-passing perforated disc 18;

[0067] The second cylinders 19 are provided in two numbers, and the two second cylinders 19 are vertically and eccentrically arranged on the top of the first-stage cold platform 17 of the two-stage pulse tube refrigerator. The bottoms of the two second cylinders 19 are fixedly connected to the top of the first-stage cold platform 17 of the two-stage pulse tube refrigerator. The two second cylinders 19 are arranged inside the lead perforation disc 18, and the outer surfaces of the two second cylinders 19 that are more than 3 mm - 5 mm away from the first-stage cold platform of the two-stage pulse tube refrigerator are covered with multiple layers of anti-radiation layers;

[0068] The second-stage cold platform 20 of the two-stage pulse tube refrigerator. The second-stage cold platform 20 of the two-stage pulse tube refrigerator is arranged on the tops of the two second cylinders 19. The tops of the two second cylinders 19 are fixedly connected to the bottom of the second-stage cold platform 20 of the two-stage pulse tube refrigerator. A detection component is arranged on the top of the second-stage cold platform 20 of the two-stage pulse tube refrigerator.

[0069] It should be understood that in order to reduce the radiant heat, the outer surfaces of the three first cylinders 16 that are more than 3 mm - 5 mm away from the room-temperature flange of the two-stage pulse tube refrigerator are covered with multiple layers of anti-radiation layers, that is to say, the anti-radiation layers are not covered within 3 mm - 5 mm of the three first cylinders 16 from the room-temperature flange of the two-stage pulse tube refrigerator. The same applies to the second cylinders 19 as to the first cylinders 16. The thickness of the indium sheet is 0.1 mm.

[0070] In some specific embodiments, the support assembly further includes:

[0071] The first-stage radiation shield 21 is made of stainless steel material. The first-stage radiation shield 21 is arranged on the top of the first-stage cold platform 17 of the two-stage pulse tube refrigerator. The low-temperature suction box 6, the second cylinders 19, and the lead perforation disc 18 are all arranged inside the first-stage radiation shield 21. The bottom of the first-stage radiation shield 21 is fixedly connected to the top of the first-stage cold platform 17 of the two-stage pulse tube refrigerator through bolts;

[0072] The second-stage radiation shield 22 is made of stainless steel material. The second-stage radiation shield 22 is arranged on the top of the first-stage radiation shield 21. The top of the first-stage radiation shield 21 is fixedly connected to the bottom of the second-stage radiation shield 22. The inner diameter of the second-stage radiation shield 22 matches the inner diameter of the first-stage radiation shield 21. A first opening 23 for the cold finger 4 to pass through is arranged on the top of the second-stage radiation shield 22, and the inner diameter of the first opening 23 is larger than the outer diameter of the low-temperature blackbody radiation blackboard 5;

[0073] The detector cold shield 24, the outer diameter of the detector cold shield 24 is smaller than the inner diameter of the secondary radiation shield 22, the height of the detector cold shield 24 is smaller than the height of the secondary radiation shield 22, the detector cold shield 24 is made of aluminum alloy material, the outer side wall of the detector cold shield 24 is covered with a radiation-resistant layer, the inner side wall of the detector cold shield 24 is blackened by sandblasting, one detection hole is provided at the top of the detector cold shield 24, the diameter of the detection hole is smaller than the diameter of the cryogenic blackbody radiation blackboard 5, the top surface of the detector cold shield 24 is blackened by sandblasting, and the bottom of the detector cold shield 24 is fixedly connected to the top of the secondary cold stage 20 of the secondary pulse tube refrigerator through bolts. The diameter of the detection hole is determined according to the optical F number.

[0074] It should be understood that the sandblasting is 80# sandblasting.

[0075] In some specific embodiments, the detection assembly includes:

[0076] The detector substrate 25 is disposed on the top of the secondary cold stage 20 of the secondary pulse tube refrigerator. The detector substrate 25 is an alumina ceramic substrate or a aluminum nitride ceramic substrate. The bottom of the detector 7 is adhesively connected to the top of the detector substrate 25 through a cryogenic adhesive. The detector substrate 25 and the detector 7 are connected by wire bonding.

[0077] The substrate pressing block 26 has an annular cross-section. The substrate pressing block 26 is disposed on the top of the detector substrate 25. The substrate pressing block 26 abuts against the detector substrate 25. The substrate pressing block 26 is fixedly connected to the secondary cold stage 20 of the secondary pulse tube refrigerator through bolts. The bottom of the detector substrate 25 is tightly attached to the top of the secondary cold stage 20 of the secondary pulse tube refrigerator by the extrusion of the substrate pressing block 26. An indium sheet is placed between the detector substrate 25 and the secondary cold stage 20 of the secondary pulse tube refrigerator.

[0078] The electrode pin plate 27 is disposed on the top of the secondary cold stage 20 of the secondary pulse tube refrigerator. An indium sheet is placed between the electrode pin plate 27 and the secondary cold stage 20 of the secondary pulse tube refrigerator. And the substrate pressing block 26 is located inside the electrode pin plate 27. The motor pin plate 27 is electrically connected to the connector 13 through a wire passing through the lead perforation plate 18 and the wire passing hole 15 in sequence. The electrode pin plate 27 is electrically connected to the detector 7 through a lead, realizing the communication of the detector 7.

[0079] It should be understood that the low temperature required for the detector 7 test is provided by the cold quantity of the secondary cold stage of the secondary pulse tube refrigerator. The cold quantity is transmitted to the detector 7 through the indium sheet, the detector substrate 25, and the cryogenic adhesive. The lead is an enameled low heat leakage lead and is connected to the pins inside the connector 13 through the enameled low heat leakage lead.

[0080] In some specific embodiments, the cryogenic suction box 6 includes:

[0081] A box body 28, the bottom of the box body 28 is fixedly connected to the top of the first-stage cold platform 17 of the second-stage pulse tube refrigerator, an indium sheet is placed between the box body 28 and the first-stage cold platform 17 of the second-stage pulse tube refrigerator, and columnar activated carbon is placed inside the box body 28;

[0082] The box cover 29 is arranged on the top of the box body 28 , and a plurality of air outlet holes 32 are arranged on the top of the box cover 29 . The inner diameter of the air outlet holes 32 is smaller than the outer diameter of the columnar activated carbon. The box cover 29 is fixedly connected to the box body 28 .

[0083] It should be understood that after the columnar getter material, i.e., columnar activated carbon, is cleaned, it is vacuum-baked and exhausted at 120 degrees for more than 24 hours, and the vacuum degree is better than 5×10 -4 Pa vacuum baking exhaust, before taking out the vacuum, high-purity nitrogen needs to be filled into the vacuum chamber; columnar activated carbon is loaded into the suction box body, and the suction box body and the suction box cover are fixed with screws. 0.1 indium pads ensure better thermal contact.

[0084] In some specific embodiments, the box body 28 and the box cover 29 are both made of aluminum alloy.

[0085] After the present invention uses external vacuum pumping equipment to complete the vacuum exhaust of the device of the present invention, the vacuum valve seat and the vacuum valve plug on the outer surface of the secondary shell 31 realize the vacuum airtightness of the present invention. When the secondary pulse tube refrigerator 1 cools down, the low-temperature energy generated by the primary cold platform 17 of the secondary pulse tube refrigerator is transmitted to the columnar activated carbon in the low-temperature suction box 6, and the columnar activated carbon will begin to non-selectively adsorb gas, thereby realizing the vacuum maintenance of the device of the present invention.

[0086] The screening method of the present invention:

[0087] 1) Fill high-purity nitrogen through the vacuum valve seat and valve plug of the secondary housing 31, then remove the screws of the low-temperature blackbody housing 10 and the secondary housing 31, and remove the low-temperature blackbody housing 10; then remove the secondary radiation shield 22 and the detector cold shield 24 in turn;

[0088] 2) At the electrode reserved point outside the circumference of the embedded inner lead wire of the detector substrate 25, the infrared detector 7 to be screened and tested is glued to the detector substrate 25, and the electrical bonding end of the detector 7 readout circuit is electrically connected to the inner side bonding of the embedded electrode of the detector substrate 25 by ultrasonic bonding;

[0089] 3) After the detector substrate 25 is fixed on the secondary cold platform 20 of the secondary pulse tube refrigerator by the substrate pressing block 26, the outer end of the pre-buried lead of the detector 7 is electrically connected to the needle on the electrode needle disk 27 by electric welding. The end of the electrode needle disk 27 is welded first, and when welding the electrode reserved point outside the circumference of the pre-buried inner lead of the detector substrate 25, the soldering iron needs to be turned off for welding;

[0090] 4) Install the detector cold shield 24, the secondary radiation shield 22, and the cryogenic blackbody housing 10 in sequence; then evacuate the present invention, requiring the evacuation time to be greater than 4 hours and the vacuum degree to be better than 1×10 -4 Pa;

[0091] 5) Convert the weak radiation energy density into the cryogenic temperature T0 of the cryogenic blackbody housing 10; set the temperature control point of the linear refrigerator 3 at T0 degrees;

[0092] 6) When starting up and cooling down the secondary pulse tube refrigerator 1, make the screening infrared detector 7 work at the required temperature; when starting up and cooling down the linear refrigerator 3, make the cryogenic blackbody radiation blackboard work at T0 degrees;

[0093] 7) Collect the performance of the detector 7 to be screened and tested through a dedicated test system; after the collection is completed, change the temperature control point of the linear refrigerator 3, set it at T0 + 15K, and then let the linear refrigerator 3 stabilize the temperature of the cryogenic blackbody radiation blackboard 5 at T0 + 15K again; after stabilizing for 15 minutes, collect the performance of the detector 7 to be screened and tested through a dedicated test system;

[0094] 8) Then perform shutdown operations on the linear refrigerator 3 and the secondary pulse tube refrigerator 1 in sequence. After the detector 7 and the cryogenic blackbody radiation blackboard 5 both return to room temperature, fill high-purity nitrogen through the vacuum valve seat and valve plug of the cylindrical housing of the secondary housing 31, then remove the screws of the cryogenic blackbody housing 10 and the secondary housing 31, and move the cryogenic blackbody housing 10 away; then remove the secondary radiation shield 22 and the detector cold shield 24 in sequence;

[0095] 9) After the soldering iron is powered off, use the remaining heat to untie the leads of the detector substrate 25 and the needles on the electrode pin board 27; disassemble the substrate pressing block 26 and move the detector substrate 25 with the detector 7 out of the device of the present invention;

[0096] 10) Install the detector cold shield 24, the secondary radiation shield 22, and the cryogenic blackbody housing 10 in sequence; then evacuate the present invention, and the evacuation time is 30 minutes;

[0097] The above completes the performance screening test of the infrared detector with weak radiation energy input of the present invention.

[0098] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A cryogenic vacuum device for testing the dark current and low background of an infrared detector, characterized in that Comprising: A two-stage pulse tube refrigerator, the outer circumferential fixed end of the top of the compressor of the two-stage pulse tube refrigerator is connected to a room temperature flange of the two-stage pulse tube refrigerator; A housing assembly, the bottom of the housing assembly is fixedly and hermetically connected to the room temperature flange of the two-stage pulse tube refrigerator by bolts, a linear refrigerator is arranged at the top of the housing assembly, the cold finger of the linear refrigerator is fixedly connected to the top of the housing assembly through a mounting seat, the bottom of the cold finger extends into the interior of the housing assembly, the bottom of the cold finger is used for fixing a low-temperature blackbody radiation blackboard, and an indium sheet is padded between the cold finger and the low-temperature blackbody radiation blackboard; A support assembly, the support assembly is arranged inside the housing assembly, and the bottom of the support assembly is fixedly connected to the room temperature flange of the two-stage pulse tube refrigerator, and a low-temperature suction box is arranged inside the support assembly; A detection assembly, the detection assembly is arranged inside the support assembly, and the top of the detection assembly is used for placing a detector.

2. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 1, wherein The housing assembly includes: A primary outer shell, the primary outer shell is arranged on the top of the room temperature flange of the two-stage pulse tube refrigerator, and the bottom of the primary outer shell is fixedly and hermetically connected to the room temperature flange of the two-stage pulse tube refrigerator through a rubber ring and bolts, two connection holes are symmetrically arranged on both side walls of the top of the primary outer shell, and two connection components are arranged on both side walls of the top of the primary outer shell corresponding to the two connection holes; A secondary outer shell, the secondary outer shell is arranged on the top of the primary outer shell, and the bottom of the secondary outer shell is fixedly and hermetically connected to the top of the primary outer shell through a rubber ring and bolts, a vacuum valve seat for evacuating the interior of the housing assembly is welded on the outer side wall of the secondary outer shell, and a vacuum valve plug is installed on the vacuum valve seat; A low-temperature blackbody outer shell, the low-temperature blackbody outer shell is arranged on the top of the secondary outer shell, and the bottom of the low-temperature blackbody outer shell is fixedly and hermetically connected to the top of the secondary outer shell through a rubber ring and bolts, the mounting end of the linear refrigerator is fixedly connected to the top of the low-temperature blackbody outer shell, a through hole is arranged on the top of the low-temperature blackbody outer shell corresponding to the mounting seat, the bottom of the mounting seat is fixedly and hermetically connected to the top of the low-temperature blackbody outer shell, the side wall of the cold finger is fixedly connected to the mounting seat, and the bottom of the cold finger extends downward through the through hole into the interior of the low-temperature blackbody outer shell.

3. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 2, characterized in that, The axis of the room temperature flange of the two-stage pulse tube refrigerator coincides with the axes of the primary outer shell, the secondary outer shell, the low-temperature blackbody outer shell, the mounting seat, the detector, and the through hole, and the axial cross-sections of the primary outer shell, the secondary outer shell, and the low-temperature blackbody outer shell are all in an I-shaped structure.

4. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 2, wherein, The connection component includes: A connection box, the top of the connection box is fixedly connected to the side wall of the top of the primary outer shell, and a connector is arranged on the side of the connection box away from the primary outer shell; A wall-penetrating board, the wall-penetrating board is clamped inside the connection hole, the outer diameter of the wall-penetrating board matches the inner diameter of the connection hole, a wire-passing hole is arranged on the wall-penetrating board, and the interior of the wall-penetrating board and the connection box is sealed and connected to the secondary outer shell through potting.

5. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 4, wherein The low-temperature blackbody radiation blackboard is made of aluminum alloy material. The bottom surface of the low-temperature blackbody radiation blackboard is provided with triangular end threads. The bottom surface of the low-temperature blackbody radiation blackboard is blackened by graphene spraying. The top surface of the low-temperature blackbody radiation blackboard is covered with a radiation-proof aluminum film.

6. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 5, characterized in that The support assembly includes: Three first cylinders, all of which are vertically arranged on the top of the room-temperature flange of the two-stage pulse tube refrigerator, and the bottoms of the three first cylinders are fixedly connected to the top of the room-temperature flange of the two-stage pulse tube refrigerator. The outer surfaces of the three first cylinders more than 3 mm - 5 mm away from the room-temperature flange of the two-stage pulse tube refrigerator are covered with multiple anti-radiation layers; The first-stage cold platform of the two-stage pulse tube refrigerator is arranged on the tops of the three first cylinders. The bottom of the first-stage cold platform of the two-stage pulse tube refrigerator is fixedly connected to the tops of the three first cylinders. A lead perforation plate is fixedly connected to the first-stage cold platform of the two-stage pulse tube refrigerator. The transverse section of the lead perforation plate is an annular structure. The low-temperature suction box is arranged on the top of the first-stage cold platform of the two-stage pulse tube refrigerator, and the low-temperature suction box is arranged inside the lead perforation plate; Two second cylinders, which are vertically and eccentrically arranged on the top of the first-stage cold platform of the two-stage pulse tube refrigerator. The bottoms of the two second cylinders are fixedly connected to the top of the first-stage cold platform of the two-stage pulse tube refrigerator. The two second cylinders are arranged inside the lead perforation plate. The outer surfaces of the two second cylinders more than 3 mm - 5 mm away from the first-stage cold platform of the two-stage pulse tube refrigerator are covered with multiple anti-radiation layers; The second-stage cold platform of the two-stage pulse tube refrigerator is arranged on the tops of the two second cylinders. The tops of the two second cylinders are fixedly connected to the bottom of the second-stage cold platform of the two-stage pulse tube refrigerator. The detection assembly is arranged on the top of the second-stage cold platform of the two-stage pulse tube refrigerator.

7. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 6, characterized in that The support assembly further includes: The first-stage radiation screen is made of stainless steel material. The first-stage radiation screen is arranged on the top of the first-stage cold platform of the two-stage pulse tube refrigerator. The low-temperature suction box, the second cylinders, and the lead perforation plate are all arranged inside the first-stage radiation screen. The bottom of the first-stage radiation screen is fixedly connected to the top of the first-stage cold platform of the two-stage pulse tube refrigerator through bolts; The second-stage radiation screen is made of stainless steel material. The second-stage radiation screen is arranged on the top of the first-stage radiation screen. The top of the first-stage radiation screen is fixedly connected to the bottom of the second-stage radiation screen. The inner diameter of the second-stage radiation screen matches the inner diameter of the first-stage radiation screen. The top of the second-stage radiation screen is provided with a first opening for the cold finger to pass through, and the inner diameter of the first opening is larger than the outer diameter of the low-temperature blackbody radiation blackboard; Detector cold shield, the outer diameter of the detector cold shield is smaller than the inner diameter of the secondary radiation shield, the height of the detector cold shield is smaller than the height of the secondary radiation shield, the detector cold shield is made of aluminum alloy material, the outer side wall of the detector cold shield is covered with a radiation-resistant layer, the inner side wall of the detector cold shield is blackened by sandblasting, there is 1 detection hole opened at the top of the detector cold shield, the diameter of the detection hole is smaller than the diameter of the cryogenic blackbody radiation blackboard, the top surface of the detector cold shield is blackened by sandblasting, and the bottom of the detector cold shield is fixedly connected to the top of the secondary cold stage of the secondary pulse tube refrigerator through bolts.

8. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 7, characterized in that, The detection assembly includes: Detector substrate, the detector substrate is arranged on the top of the secondary cold stage of the secondary pulse tube refrigerator, the detector substrate is an alumina ceramic substrate or a aluminum nitride ceramic substrate, the bottom of the detector is adhesively connected to the top of the detector substrate through a cryogenic adhesive, and the detector substrate and the detector are connected by wire bonding; Substrate pressing block, the transverse cross-section of the substrate pressing block is an annular structure, the substrate pressing block is arranged on the top of the detector substrate, the substrate pressing block abuts against the detector substrate, the substrate pressing block is fixedly connected to the secondary cold stage of the secondary pulse tube refrigerator through bolts, the bottom of the detector substrate is tightly attached to the top of the secondary cold stage of the secondary pulse tube refrigerator by the extrusion of the substrate pressing block, and an indium sheet is padded between the detector substrate and the secondary cold stage of the secondary pulse tube refrigerator; Electrode pin plate, the electrode pin plate is arranged on the top of the secondary cold stage of the secondary pulse tube refrigerator, an indium sheet is padded between the electrode pin plate and the secondary cold stage of the secondary pulse tube refrigerator, and the substrate pressing block is located inside the electrode pin plate. The motor pin plate is electrically connected to the connector through a wire passing through the lead perforation plate and the wire passing hole in sequence, and the electrode pin plate is electrically connected to the detector through a lead.

9. The cryogenic vacuum device for infrared detector dark current and low background testing according to claim 8, characterized in that The cryogenic suction box includes: Box body, the bottom of the box body is fixedly connected to the top of the primary cold stage of the secondary pulse tube refrigerator, an indium sheet is padded between the box body and the primary cold stage of the secondary pulse tube refrigerator, and columnar activated carbon is placed inside the box body; Box cover, the box cover is arranged on the top of the box body, and a plurality of air outlet holes are arranged on the top of the box cover. The inner diameter of the air outlet holes is smaller than the outer diameter of the columnar activated carbon, and the box cover is fixedly connected to the box body.

10. The cryogenic vacuum device for infrared detector dark current and low background test according to claim 9, characterized in that, Both the box body and the box cover are made of aluminum alloy.

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