Dewar internal atmosphere testing and analyzing device and testing and analyzing method thereof

Abstract

The application discloses a Dewar internal atmosphere testing and analyzing device and a testing and analyzing method, which comprises a first valve, a first molecular pump, a first partition valve, a first dry pump, a quadrupole mass spectrometer, a second valve, a high vacuum gauge, a heating cover, a Dewar assembly to be tested, a heating cover support, a composite vacuum gauge, a third valve, a second molecular pump, a second partition valve and a second dry pump; the quadrupole mass spectrometer and the high vacuum gauge constitute a testing and analyzing system; the heating cover, the Dewar assembly to be tested and the composite vacuum gauge constitute a gas accumulation heating system; the first dry pump, the first partition valve, the first molecular pump and the first valve constitute a main pumping system; the second dry pump, the second partition valve, the second molecular pump and the third valve constitute an auxiliary pumping system; and the testing and analyzing system and the gas accumulation heating system are connected through the second valve. The application adopts a static accumulation method to improve sensitivity and adopts independent pumping to avoid that equipment pollutes the gas accumulation heating system.

Description

Technical Field

[0001] This invention relates to the field of internal atmosphere analysis of infrared detector Dewar components, and specifically to a device and method for testing and analyzing the internal atmosphere of a Dewar. Background Technology

[0002] As infrared detectors continue to evolve towards larger arrays and higher resolutions, the requirements for Dewar vacuum lifetime are becoming increasingly stringent, especially with the application of new materials and processes posing a severe challenge to Dewar vacuum lifetime. Furthermore, there is an urgent need to analyze the internal atmosphere of Dewars in samples that have experienced early vacuum failure, but currently, relevant technical methods are lacking.

[0003] Currently, commonly used internal atmosphere analyzers are developed by IPI (Germany) or ORS (USA), both employing dynamic detection methods. For example, the ORS IVA110-S internal atmosphere analyzer consists of a sample chamber, an analysis chamber, and a vacuum system. The sample chamber releases gas from sealed components into the testing system through perforations; the analysis chamber includes a four-stage mass spectrometer to analyze the gas composition; and the vacuum system achieves a good vacuum level and background.

[0004] Currently, Ge Shuping et al. from the Kunming Institute of Physics reported in the paper "Experimental Study on Residual Gas Analysis of Dewar Exhaust Gas in Infrared Focal Plane Dewar" (Infrared Technology, No. 28, 2006) that they used a quadrupole mass spectrometer to detect the gas composition during the dewar exhaust process, and the detection process adopted a dynamic method.

[0005] The aforementioned devices and methods generally suffer from problems such as poor test sensitivity and contamination. Summary of the Invention

[0006] The technical problem to be solved by this invention is:

[0007] (1) To address the problem of poor sensitivity in traditional internal atmosphere analyzer detection methods, a high-sensitivity Dewar internal atmosphere testing and analysis device and method is provided. This structure is also suitable for other vacuum-packed devices that require high-sensitivity internal atmosphere analysis.

[0008] (2) To address the pollution problem in the testing and analysis room, a simple and reliable isolation measure is provided to avoid large amounts of gaseous contamination of the equipment in the initial state of the workpiece.

[0009] The technical solution of this invention is as follows:

[0010] A Dewar internal atmosphere testing and analysis device includes a first valve, a first molecular pump, a first isolation valve, a first dry pump, a quadrupole mass spectrometer, a second valve, a high vacuum gauge, a heating hood, a Dewar component under test, a heating hood support, a composite vacuum gauge, a third valve, a second molecular pump, a second isolation valve, and a second dry pump. The quadrupole mass spectrometer and the high vacuum gauge are connected by pipelines to form a testing and analysis system. The heating hood, the Dewar component under test, the heating hood support, and the composite vacuum gauge constitute a gas accumulation heating system. The heating hood covers the Dewar component under test, and the heating hood support supports the heating hood. The Dewar component under test is connected to the composite vacuum gauge by pipelines. The first dry pump, the first isolation valve, the first molecular pump, and the first valve are sequentially connected to form a main pumping system, which is connected to the testing and analysis system through the first valve. The second dry pump, the second isolation valve, the second molecular pump, and the third valve are sequentially connected to form an auxiliary pumping system, which is connected to the gas accumulation heating system through the third valve. The testing and analysis system and the gas accumulation heating system are connected by the second valve.

[0011] Furthermore, the Dewar assembly under test is interconnected with the second valve, the composite vacuum gauge, and the third valve via an exhaust pipe.

[0012] Furthermore, the first valve, the second valve, and the third valve are all all-metal sealed gate valves or all-metal sealed angle valves.

[0013] Furthermore, the quadrupole mass spectrometer has a mass number range of 1-200 Amu and is equipped with an electron multiplier.

[0014] Furthermore, the high vacuum gauge adopts the BA type vacuum gauge, with a measurement lower limit better than 1×10⁻⁶. -9 mabr; The measurement range of the composite vacuum gauge is 1 atm - 1 × 10 -9 mabr.

[0015] Furthermore, the exhaust pipe connecting the Dewar component under test to the gas accumulation heating system uses a soft metal pipe transition to form a reliable sealed connection.

[0016] Furthermore, the interfaces of the all-metal sealed gate valve or all-metal sealed angle valve adopt a knife-edge sealing method, and the specifications include CF16, CF35, CF63 or CF100.

[0017] The specific testing and analysis method using the Dewar internal atmosphere testing and analysis device of the present invention is as follows:

[0018] S1: To achieve a reliable sealed connection between the Dewar component under test and the second valve, the composite vacuum gauge and the third valve through a soft metal tube; and to ensure that the second valve is in the closed state.

[0019] S2: Sequentially open the first dry pump, the first isolation valve, the first molecular pump, and the first valve to heat and bake the test and analysis system, continuously evacuating the vacuum until the high vacuum gauge is better than 1×10⁻⁶. -9 mabr.

[0020] S3: Sequentially open the second dry pump, the second isolation valve, the second molecular pump, and the second valve to heat and bake the gas accumulation heating system, and continuously evacuate until the composite vacuum gauge is better than 1×10. -9 mabr.

[0021] S4: The Dewar component under test is continuously baked and degassed through the heating cover, heating cover bracket and its temperature control device, and the temperature is controlled at 60-100℃.

[0022] S5: The third valve is closed to allow gas accumulation. The accumulation time is adjustable, and the amount of accumulated gas is monitored by a composite vacuum gauge.

[0023] S6: After the gas accumulation is complete, close the first valve and turn on the quadrupole mass spectrometer to perform a background atmosphere test. The scanning time is between 30 and 300 seconds.

[0024] S7: Open the second valve and scan the mass spectrometer for changes. The scanning time is 30-300 seconds.

[0025] S8: Connect the standard gas and repeat the above process.

[0026] S9: Test complete. Open the third valve and the first isolation valve to continue vacuuming and obtain a lower equipment background.

[0027] The advantages of this invention compared to the prior art are:

[0028] (1) The present invention uses static accumulation state for atmosphere analysis (i.e., the all-metal valve between the molecular pump and the gas accumulation heating system is closed, and the all-metal valve between the molecular pump and the test and analysis system is closed), which can significantly enhance the detection sensitivity. At the same time, the baking temperature and time of the sample can be flexibly adjusted according to different application requirements to meet different application needs.

[0029] (2) The gas accumulation heating system and the test analysis system used in this invention are arranged separately with all-metal valves. They are interconnected through the test valves and each uses an independent gas extraction system, which avoids equipment contamination and significantly improves the detection efficiency.

[0030] (3) The Dewar internal atmosphere testing and analysis device of the present invention has convenient sample accumulation time adjustment and can flexibly adjust the gas volume according to different application requirements.

[0031] (4) The gas accumulation heating system and the testing and analysis system of the Dewar internal atmosphere testing and analysis device of the present invention are arranged separately to avoid contamination of the equipment.

[0032] (5) The Dewar internal atmosphere testing and analysis device of the present invention adopts the cumulative gas method in the testing process, and its testing sensitivity is more than two orders of magnitude higher than that of the standard internal atmosphere analyzer. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the composition of the high-sensitivity Dewar internal atmosphere testing and analysis device of the present invention. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] like Figure 1 As shown, a Dewar internal atmosphere testing and analysis device includes a first VAT all-metal angle valve 1, a first molecular pump 2, a first isolation valve 3, a first dry pump 4, a quadrupole mass spectrometer 5, a second VAT all-metal angle valve 6, a high vacuum gauge 7, a heating hood 8, a Dewar component to be tested 9, a heating hood support 10, a composite vacuum gauge 11, a third VAT all-metal angle valve 12, a second molecular pump 13, a second isolation valve 14, and a second dry pump 15.

[0036] The quadrupole mass spectrometer 5, the high vacuum gauge 7, and their piping constitute the testing and analysis system; the Dewar assembly 9, the composite vacuum gauge 11, and their piping constitute the gas accumulation heating system; the first VAT all-metal angle valve 1, the first molecular pump 2, the first isolation valve 3, and the first dry pump 4 are connected in sequence and transferred to the testing and analysis system; the third VAT all-metal angle valve 12, the second molecular pump 13, the second isolation valve 14, and the second dry pump 15 are connected in sequence and transferred to the gas accumulation heating system; the testing and analysis system and the gas accumulation heating system are separated by the second VAT all-metal angle valve 6; the Dewar assembly forms a heating system through the heating cover 8, the heating cover support 10, and their temperature control device.

[0037] Among them, the Dewar component 9 under test is connected to the gas accumulation heating system through the exhaust pipe, and a highly reliable sealed connection is formed by using soft metal InSn transition.

[0038] Among them, the first VAT all-metal angle valve 1, the second VAT all-metal angle valve 6, and the third VAT all-metal angle valve 12 are all-metal sealed angle valves DN40, and their interfaces adopt knife-edge sealing method and adopt CF35 specification.

[0039] Among them, the quadrupole mass spectrometer 5 uses the Pufa QMG250, with a mass number range of 1-200 Amu and an electron multiplier.

[0040] Among them, the high vacuum gauge 7 adopts the BA type vacuum gauge, and the lower limit of measurement is better than 1×10. -9 The measurement range of the composite vacuum gauge 11 is 1 atm - 1 × 10⁻¹⁰. -9 mabr.

[0041] See Figure 1 A method for performing testing and analysis using the Dewar internal atmosphere testing and analysis device of the present invention is as follows:

[0042] S1: The second VAT all-metal angle valve 6 is in the closed state.

[0043] S2: Sequentially open the first dry pump 4, the first isolation valve 3, the first molecular pump 2, and the first VAT all-metal angle valve 1 to heat and bake the test and analysis system, and continuously evacuate until the high vacuum gauge 7 is better than 1×10. -9 mabr.

[0044] S3: Sequentially open the second dry pump 15, the second isolation valve 14, the second molecular pump 13, and the second VAT all-metal angle valve 12 to heat and bake the gas accumulation heating system, and continuously evacuate until the composite vacuum gauge 11 is better than 1×10. -9 mabr.

[0045] S4: The Dewar component 9 to be tested is continuously baked and degassed through the heating cover 8, the heating cover support 10 and its temperature control device, and the temperature is controlled at 80℃.

[0046] S5: The third valve 12 is closed to allow gas accumulation. The accumulation time is adjustable, and the amount of accumulated gas is monitored by the composite vacuum gauge 11.

[0047] S6: After the gas accumulation is complete, close the first valve 1 and turn on the quadrupole mass spectrometer 5 to perform the background atmosphere test. The scanning time is 100 seconds.

[0048] S7: Open the second valve 6 and scan the mass spectrometer for 100 seconds.

[0049] S8: Introduce standard gas CO2 and repeat the above process.

[0050] S9: Test complete. Open the third valve 12 and the first isolation valve 3 to continue vacuuming and obtain a lower equipment background.

[0051] The calculation method is illustrated below using the analysis of CO2 gas content as an example. Testing the CO2 gas content of the workpiece requires measuring three types of signal parameters with a mass number of 44: the background signal rise rate, the workpiece-carrying signal rise rate, and the standard gas signal rise rate. The main valve must be closed for each signal measurement; however, the standard leak valve should be opened when measuring the standard leak signal.

[0052] S1: Base signal rise rate:

[0053]

[0054] In the formula, P 01 The initial CO2 ion current value; P 11 T represents the CO2 ion current value at the end of the accumulation time. 01 For the corresponding P 01 The initial time; T 11 For the corresponding P 11 The corresponding time.

[0055] S2: Workpiece signal rise rate

[0056]

[0057] In the formula, P 02 P represents the CO2 ion current value under the initial pressure of the workpiece. 12 T represents the CO2 ion current value at the end of the accumulation time. 02 For the corresponding P 02 The initial time; T 12 For the corresponding P 12 The corresponding time.

[0058] S3: Net signal increment

[0059] I 增 =I 工件 -I 本底

[0060] S4: Standard gas signal rise rate

[0061]

[0062] In the formula, P 03 P represents the CO2 ion current value under the initial pressure of the workpiece. 13 T represents the CO2 ion current value at the end of the accumulation time. 03 For the corresponding P 03 The initial time; T 13 For the corresponding P 13 The corresponding time.

[0063] S5: Standard gas calibration flow rate is Q0

[0064] S6: Test the CO2 gas flow rate of the workpiece.

[0065]

[0066] The analysis of commonly used gases is achieved by monitoring the signals of the corresponding mass numbers. For example, mass number 18 is used to monitor water vapor, mass number 2 is used to monitor hydrogen, mass number 16 is used to monitor methane, mass number 32 is used to monitor oxygen, and mass number 40 is used to monitor argon. The calculation method is similar and will not be described in detail here.

Claims

1. A method for testing and analyzing the internal atmosphere of a Dewar, utilizing a Dewar internal atmosphere testing and analysis device, the device comprising a first valve (1), a first molecular pump (2), a first isolation valve (3), a first dry pump (4), a quadrupole mass spectrometer (5), a second valve (6), a high vacuum gauge (7), a heating hood (8), a Dewar component to be tested (9), a heating hood support (10), a composite vacuum gauge (11), a third valve (12), a second molecular pump (13), a second isolation valve (14), and a second dry pump (15); The quadrupole mass spectrometer (5) and the high vacuum gauge (7) are connected by pipelines to form a test and analysis system; The heating cover (8), the Dewar assembly to be tested (9), the heating cover bracket (10) and the composite vacuum gauge (11) constitute a gas accumulation heating system. The heating cover (8) covers the Dewar assembly to be tested (9), and the heating cover bracket (10) is used to support the heating cover (8). The Dewar assembly to be tested (9) and the composite vacuum gauge (11) are connected by a pipeline. The first dry pump (4), the first isolation valve (3), the first molecular pump (2) and the first valve (1) are connected in sequence to form the main air extraction system, and are transferred to the test and analysis system through the first valve (1); The second dry pump (15), the second isolation valve (14), the second molecular pump (13) and the third valve (12) are connected in sequence to form an auxiliary gas extraction system, and are transferred to the gas accumulation heating system through the third valve (12); The test and analysis system is connected to the gas accumulation heating system via the second valve (6); Its features are, Includes the following steps: S1: This puts the second valve (6) in the closed state; S2: Sequentially open the first dry pump (4), the first isolation valve (3), the first molecular pump (2), and the first valve (1) to heat and bake the test and analysis system, and continuously evacuate until the vacuum degree of the high vacuum gauge (7) is better than 1×10⁻⁶. -9 mabr; S3: Sequentially open the second dry pump (15), the second isolation valve (14), the second molecular pump (13), and the third valve (12) to heat and bake the gas accumulation heating system, and continuously evacuate until the vacuum degree of the composite vacuum gauge (11) is better than 1×10. -9 mabr; S4: The Dewar assembly (9) to be tested is continuously baked and degassed through the heating cover (8), and the temperature is controlled at 60-100℃; S5: The third valve (12) is closed to accumulate gas. The accumulation time is adjustable and the amount of accumulated gas is monitored by the composite vacuum gauge (11). S6: After the gas accumulation is completed, close the first valve (1) and turn on the quadrupole mass spectrometer (5) to perform the background atmosphere test of the equipment. The scanning time is 30 seconds to 300 seconds. S7: Open the second valve (6) and scan the mass spectrometry changes. The scanning time is 30-300 seconds. S8: Connect the standard gas and repeat the above process; S9: Test completed. Open the third valve (12) and the first isolation valve (3) to continuously pump vacuum and obtain a lower equipment background.

2. The test and analysis method according to claim 1, characterized in that, To test and analyze the CO2 gas content, the CO2 gas quantity of the workpiece needs to be measured using three types of signal parameters with a mass number of 44. These three types of signal parameters are the background signal rise rate, the workpiece signal rise rate, and the standard gas signal rise rate. The main valve needs to be closed for each signal measurement, but the standard leak valve should be opened when measuring the standard leak signal. include: (1) Baseline signal rise rate I 本底 ， In the formula, This represents the initial CO2 ion current value. This represents the CO2 ion current value at the end of the accumulation period; For the corresponding The initial time; For the corresponding The corresponding time; (2) Workpiece signal rise rate I 工件 ， In the formula, This represents the CO2 ion current value under the initial pressure of the workpiece; This represents the CO2 ion current value at the end of the accumulation period; For the corresponding The initial time; For the corresponding The corresponding time; (3) Net signal increment I 增 ； (4) Standard gas signal rise rate I 标 ， In the formula, This represents the CO2 ion current value under the initial pressure of the workpiece; This represents the CO2 ion current value at the end of the accumulation period; For the corresponding The initial time; For the corresponding The corresponding time; (5) The standard gas calibration flow rate is ; (6) Test the CO2 gas flow rate Q of the workpiece co2 。 3. The test and analysis method according to claim 1, characterized in that: The test analysis uses mass number 18 to monitor water vapor, mass number 2 to monitor hydrogen, mass number 16 to monitor methane, mass number 32 to monitor oxygen, and mass number 40 to monitor argon.

4. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 1, characterized in that: The Dewar assembly (9) to be tested is connected to the second valve (6), the composite vacuum gauge (11) and the third valve (12) through the exhaust pipe.

5. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 1, characterized in that: The first valve (1), the second valve (6), and the third valve (12) are all all-metal sealed gate valves or all-metal sealed angle valves.

6. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 1, characterized in that: The quadrupole mass spectrometer (5) has a mass number range of 1-200 Amu and is equipped with an electron multiplier.

7. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 1, characterized in that: The high vacuum gauge (7) is a BA type vacuum gauge with a lower measurement limit better than 1×10⁻⁶. -9 mabr; The measurement range of the composite vacuum gauge (11) is 1 atm - 1 × 10⁻¹⁰. -9 mabr.

8. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 4, characterized in that: The exhaust pipe of the Dewar component (9) to be tested is connected to the gas accumulation heating system by a soft metal pipe to form a reliable sealed connection.

9. The method for testing and analyzing the internal atmosphere of a Dewar flask according to claim 5, characterized in that: The interface of the all-metal sealed gate valve or all-metal sealed angle valve adopts a knife-edge sealing method, and the specifications include CF16, CF35, CF63 or CF100.

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