A temperature sensor package and calibration apparatus and method

Abstract

The application relates to a temperature sensor packaging and calibration device and method, which comprises a closed cavity formed by a flange top seat, a Dewar cavity wall and a flange bottom seat, a refrigerator interface, a vacuum extraction port, a vacuum gauge interface and a vacuum penetration circuit board are welded on the flange bottom seat, a Stirling refrigerator is installed at the refrigerator interface, and a cold head of the Stirling refrigerator is located in the closed cavity; the device further comprises an isothermal platform, the isothermal platform is provided with a standard temperature sensor and an aluminum substrate, sensor solder pads, signal line lead solder pads and signal line fixed solder pads are welded on the aluminum substrate, and a temperature sensor to be measured is welded on the sensor solder pads. According to the above technical scheme, the temperature sensor to be measured is fixed through the aluminum substrate, so that heat conduction is enhanced and heat accumulation is reduced, and the standard temperature sensor is used as a calibration standard, low-temperature refrigeration is carried out in the vacuum cavity by using the refrigerator, and the calibration of the temperature sensor is carried out in the temperature range of -200 to 0 DEG C.

Description

Technical Field

[0001] This invention relates to the field of temperature sensor packaging and calibration, and specifically to a temperature sensor packaging and calibration device and method. Background Technology

[0002] In the field of cryogenic vacuum packaging of detectors, accurate temperature measurement is crucial, especially for semiconductor detectors. To reduce dark current, cooling is essential to suppress it, and accurate temperature measurement is necessary to mitigate various temperature-related effects. For instance, large-area scientific cameras are often constructed by stitching together multiple detectors. The entire focal plane of the stitched camera needs to operate at low temperatures to reduce detector noise and dark current. To assess the impact of temperature deformation on the overall focal plane stitching and the effect of temperature fluctuations on detector performance, especially for applications such as high-precision photometry, the accuracy and stability of temperature measurements are critical.

[0003] Commonly used temperature sensors on the market include resistive, silicon diode, thermocouple, and radiation types. Resistive temperature sensors utilize the change in resistance of a material with temperature, and are characterized by high sensitivity and stable performance. Among them, the most representative PT100 standard platinum resistance sensor is characterized by its soft texture, ease of processing, good physical and chemical properties, and high temperature measurement accuracy, and is widely used in low-temperature and high-precision temperature measurement applications.

[0004] The relationship between the resistance of a platinum resistance thermometer and temperature is described by the Callendar-Van Dusen (CVD) equation:

[0005] (a)

[0006] (b)

[0007] in, The resistance of the platinum resistance at 0℃ is given by the following values: A = 3.9083E-3, B = -5.775E-7, and C = -4.183E-12.

[0008] Industrial platinum resistance thermometers (PTTs) are typically manufactured by depositing a thin platinum film onto a ceramic substrate, which is relatively fragile. To ensure reliability, their encapsulation typically involves placing the platinum resistor within a metal protective sleeve (copper, stainless steel, or aluminum), filled with insulating alumina (Al₂O₃) or magnesium oxide (MgO) particles with a diameter of ~80 μm, and then sealing the tail of the metal protective sleeve with sealant. Unlike ambient temperature differential pressure measurement, low-temperature thermal mismatch and pressure imbalance in the temperature sensor encapsulation structure under low-temperature vacuum conditions can cause changes in the compactness of the filling material within the metal protective sleeve, leading to variations in the interfacial thermal resistance between the actual platinum resistor and the metal protective sleeve. Furthermore, the impact of this effect varies among different temperature sensors, resulting in poor matching between sensors with this type of encapsulation when facing multi-point uniformity and consistent temperature measurement requirements.

[0009] In addition, platinum resistance thermometers have a certain resistance error when they leave the factory. The relationship between the resistance of a platinum resistance thermometer and temperature, as shown in equations (a) and (b), is non-linear. Especially when the resistance is small at low temperatures, the non-uniformity of the error of different PT100 temperature sensors will bring a large deviation to the temperature measurement and seriously affect the accuracy of temperature measurement. Summary of the Invention

[0010] The purpose of this invention is to overcome the above-mentioned drawbacks and provide a temperature sensor packaging and calibration device.

[0011] To achieve the above objectives, the present invention adopts the following technical solution: It includes a sealed cavity formed by connecting a flange top seat, a Dewar cavity wall, and a flange base. The flange base is welded with a refrigerator interface, a vacuum extraction port, and a vacuum gauge interface communicating with the sealed cavity. A Stirling refrigerator is installed at the refrigerator interface, and the cold head of the Stirling refrigerator is located within the sealed cavity. It also includes a temperature equalization platform connected to the cold head of the Stirling refrigerator. The temperature equalization platform is equipped with a standard temperature sensor and an aluminum substrate. The aluminum substrate is welded with sensor pads, signal lead pads, and signal line fixing pads. The temperature sensor to be measured is welded to the sensor pads. The aluminum substrate, the temperature sensor to be measured, the signal lead pads, the signal line fixing pads, and the sensor pads form the encapsulation structure of the temperature sensor to be measured. The flange base is also equipped with a vacuum penetration circuit board connected to the standard temperature sensor and the temperature sensor to be measured. The temperature sensor to be measured is a PT100 platinum resistance temperature sensor.

[0012] Indium sheets are provided between the aluminum substrate and the temperature equalization platform, between the standard temperature sensor and the temperature equalization platform, and between the temperature equalization platform and the cold head of the Stirling refrigerator.

[0013] The temperature equalization platform is a cylindrical copper block, and the surface of the temperature equalization platform is polished. The temperature equalization platform is equipped with a radiation shield that matches the temperature equalization platform, and the radiation shield is made of aluminum foil.

[0014] The flange top seat, Dewar cavity wall, and flange base are all made of titanium alloy or Invar steel, and the machining accuracy of the flange top seat, Dewar cavity wall, and flange base must reach the micron level. The Dewar cavity wall is sealed to the flange base and flange top seat by rubber rings.

[0015] The signal line of the standard temperature sensor is led out through a vacuum penetration circuit board and connected to an external temperature controller. The signal line of the temperature sensor under test is led out through a vacuum penetration circuit board and connected to an external temperature control board. Both the standard temperature sensor and the temperature sensor under test adopt a four-wire connection method. Two sets of signal line lead pads and two sets of signal line fixing pads are set. Each set of signal line fixing pads consists of two parallel pads.

[0016] As can be seen from the above technical solution, the device can provide a high vacuum degree, thereby providing a large calibration temperature range for the temperature sensor under test through the refrigerator, and achieving good steady-state and temperature consistency between the temperature sensor under test and the standard temperature sensor through the temperature equalization platform, improving calibration accuracy. Furthermore, the platform can calibrate multiple temperature sensors under test at one time, greatly improving calibration efficiency.

[0017] Another object of the present invention is to provide a method for packaging and calibrating a temperature sensor, comprising the following steps:

[0018] S1: Encapsulate the temperature sensor to be measured;

[0019] S2: Install the standard temperature sensor and the packaged temperature sensor to be tested on the uniform temperature platform;

[0020] S3: Fix the temperature distribution platform to the cold head of the Stirling refrigerator;

[0021] S4: Connect the temperature sensor to be measured to the vacuum penetration circuit board, and connect the standard temperature sensor to the vacuum penetration circuit board;

[0022] S5: Connect the temperature controller, temperature control board and vacuum penetration circuit board;

[0023] S6: Cover the uniform temperature platform with a radiation shield;

[0024] S7: Connect the flange top seat, Dewar cavity wall and flange base in sequence to form a sealed cavity;

[0025] S8: Install a vacuum detector at the vacuum interface and a vacuum gauge at the vacuum gauge interface;

[0026] S9: Use a vacuum detector to test the vacuum leakage rate of the sealed cavity. After the vacuum leakage rate test is qualified, remove the vacuum detector and install a vacuum pump at the vacuum port to evacuate the sealed cavity.

[0027] S10: Read the vacuum level inside the sealed cavity using a vacuum gauge. When the vacuum level inside the sealed cavity is lower than... The Stirling refrigerator is turned on for cooling.

[0028] S11: Set the operating temperature of the Stirling refrigerator cold head according to the temperature range to be calibrated. First, lower the operating temperature to the lowest temperature of the required calibration temperature range. When the temperature equalization platform is in a steady state, record the temperature difference between the temperature sensor under test and the standard temperature sensor. This temperature difference is used as the correction amount of the temperature sensor under test at that temperature. Then, increase the temperature according to a certain step size. When the temperature equalization platform is in a steady state, record the correction amount of the temperature sensor under test at each step temperature until the entire temperature range is calibrated.

[0029] S12: After calibration, remove the flange top seat and Dewar cavity wall to raise the cold head of the Stirling refrigerator to room temperature, and replace the position of the temperature sensor to be measured. Repeat S7 to S11.

[0030] S13: Take the average of the two corrections at each temperature point before and after the position swap as the final temperature correction.

[0031] In S1, the temperature sensor to be measured is a PT100 platinum resistance temperature sensor.

[0032] In S1, the encapsulation of the temperature sensor to be measured refers to first soldering the temperature sensor to be measured onto the sensor pad, then connecting the signal line of the temperature sensor to be measured to the signal line lead pad using a four-wire connection method, then fixing the signal line to the signal line fixing pad, and finally connecting the signal line to the vacuum penetration circuit board via an FPC cable to bring out the signal.

[0033] In S11, the steady state of the temperature equalization platform refers to the temperature stability of the cold head temperature monitoring point being within 10mK, and the temperature stability of the temperature sensor under test and the standard temperature sensor on the temperature equalization platform being within 8mK.

[0034] As can be seen from the above technical solution, this method can calibrate multiple temperature sensors in a single operation, achieving high calibration efficiency. The excellent thermal conductivity of the temperature equalization platform ensures that the steady-state temperatures of each temperature sensor are approximately identical. Interchanging their positions further reduces the temperature measurement deviation between each sensor under test and the standard temperature sensor, improving calibration accuracy. Using a cryogenic refrigerator, high-precision temperature sensor calibration can be achieved at temperatures as low as -200℃. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the present invention. Figure 1 ;

[0036] Figure 2 This is a schematic diagram of the overall structure of the present invention. Figure 2 ;

[0037] Figure 3 This is a schematic diagram of the internal structure of the present invention after the flange top seat is removed;

[0038] Figure 4 This is a schematic diagram of the temperature equalization platform of the present invention;

[0039] Figure 5 This is a schematic diagram of the packaging structure of the temperature sensor to be measured according to the present invention.

[0040] The labels in the above figures are as follows: 1. Flange top seat; 2. Dewar cavity wall; 3. Flange base; 31. Refrigeration machine interface; 32. Vacuum extraction port; 33. Vacuum gauge interface; 4. Stirling refrigerator; 41. Cold head; 42. Heat sink; 5. Temperature equalization platform; 6. Standard temperature sensor; 7. Temperature sensor to be measured; 7. Aluminum substrate; 71. Signal line lead pad; 72. Signal line fixing pad; 73. Sensor pad; 74. Vacuum penetration circuit board; 8. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings:

[0042] like Figure 1 , Figure 2 , Figure 3 , Figure 4The temperature sensor packaging and calibration device shown includes a sealed cavity formed by a flange top seat 1, a Dewar cavity wall 2, and a flange base 3. A refrigerator interface 31, a vacuum extraction port 32, and a vacuum gauge interface 33, all communicating with the sealed cavity, are welded to the flange base 3. A Stirling refrigerator 4 is installed at the refrigerator interface 31. The cold head 41 of the Stirling refrigerator 4 is located inside the sealed cavity, while the heat sink 42 of the Stirling refrigerator 4 is located outside the sealed cavity. The Stirling refrigerator 4 features PID temperature control and can cool down to 50K, providing sufficient cooling capacity within the temperature calibration range to provide a low-temperature environment for calibration. The device also includes a temperature equalization platform 5 connected to the cold head 41 of the Stirling refrigerator 4. A standard temperature sensor 6 and an aluminum substrate 71 are mounted on the temperature equalization platform 5, which has mounting holes for mounting the aluminum substrate 71. Specifically, the temperature equalization platform 5 is connected to the cold head 41 by screws, the standard temperature sensor 6 is attached to the temperature equalization platform 5 by aluminum foil tape, the aluminum substrate 71 is connected to the temperature equalization platform 5 by screws, and the aluminum substrate 71 is soldered with sensor pads 74, signal line lead pads 72 and signal line fixing pads 73. The temperature sensor under test 7 is soldered on the sensor pads 74. The aluminum substrate 71, the temperature sensor under test 7, the signal line lead pads 72, the signal line fixing pads 73 and the sensor pads 74 form the package structure of the temperature sensor under test 7. The flange base 3 is also provided with a vacuum penetration circuit board 8 connected to the standard temperature sensor 6 and the temperature sensor under test 7.

[0043] In this embodiment, the temperature sensor 7 to be measured is a PT100 platinum resistance temperature sensor, and the standard temperature sensor 6 is a Lakeshore PT-103-AM-14L-QT temperature sensor. The standard temperature sensor 6 can be calibrated by the manufacturer in advance and used as a benchmark for the calibration of other temperature sensors.

[0044] Furthermore, both the standard temperature sensor 6 and the temperature sensor under test 7 employ a four-wire connection. The signal line of the standard temperature sensor 6 is led out through the vacuum penetration circuit board 8 and connected to an external temperature controller. Specifically, one end of the signal line of the standard temperature sensor 6 is soldered to the FPC cable, and the other end of the FPC cable is plugged into the vacuum penetration circuit board 8. The signal is then led out through the vacuum penetration circuit board 8, and the temperature controller reads the value from the standard temperature sensor. Similarly, the signal line of the temperature sensor under test 7 is led out through the vacuum penetration circuit board 8 and connected to an external temperature control board. This means that one end of the signal line of the temperature sensor under test 7 is soldered to the FPC cable, and the other end of the FPC cable is plugged into the vacuum penetration circuit board 8. The signal is then led out through the vacuum penetration circuit board 8, and the temperature control board reads the value from the temperature sensor under test.

[0045] Furthermore, such as Figure 5As shown, the aluminum substrate 71, the temperature sensor under test 7, the signal line lead pads 72, the signal line fixing pads 73, and the sensor pads 74 form the package structure of the temperature sensor under test 7. Two sets of signal line lead pads 72 and two sets of signal line fixing pads 73 are provided. Each set of signal line fixing pads 73 consists of two parallel square pads. Initially, the temperature sensor under test 7 is packaged. Specifically, the temperature sensor under test 7 is soldered onto the sensor pads 74, and then the four-wire signal lines of the temperature sensor under test 7 are soldered onto the signal line lead pads 72. Two wires of the temperature sensor under test 7 are led out from each side. The soldered wires on both sides are then passed through the middle of the two sets of signal line fixing pads 73. Two solder bridges are then built between the two square pads in each set to fix the signal lines of the temperature sensor under test leading out from both sides, preventing the signal lines from becoming tangled. The packaging structure of the temperature sensor 7 ensures the consistency and reliability of the sensor, effectively reduces the heat generated by the sensor due to the hot spot effect, and the packaging structure does not trap gas, making it suitable for use under high vacuum.

[0046] In this embodiment, three sets of temperature sensors 7 are set up and connected to the three channels of the temperature control board respectively. In actual operation, the number of temperature sensors 7 can be selected appropriately according to the number of channels of the vacuum penetration circuit board 8 and the size of the temperature equalization platform 5.

[0047] Furthermore, indium sheets are provided between the aluminum substrate 71 and the temperature equalization platform 5, between the standard temperature sensor 6 and the temperature equalization platform 5, and between the temperature equalization platform 5 and the cold head 41 of the Stirling refrigerator 4. These indium sheets are fixed with screws, and they can reduce thermal resistance.

[0048] Furthermore, the temperature equalization platform 5 is a cylindrical copper block, and its surface is polished. Preferably, to further reduce the non-uniformity caused by surrounding radiation, the temperature equalization platform 5 is equipped with a radiation shield that works in conjunction with it. The radiation shield is made of aluminum foil. Figure 3 Not shown in the image.

[0049] Furthermore, the flange top seat 1, the Dewar cavity wall 2, and the flange base 3 are all made of materials with minimal temperature deformation, such as titanium alloy or Invar. The machining precision of the flange top seat 1, the Dewar cavity wall 2, and the flange base 3 must reach the micrometer level to ensure sealing. The Dewar cavity wall 2 is sealed to the flange base 3 and the flange top seat 1 respectively using rubber rings.

[0050] Another object of the present invention is to provide a method for packaging and calibrating a temperature sensor, comprising the following steps:

[0051] S1: Encapsulate the temperature sensor to be measured;

[0052] S2: Install the standard temperature sensor and the packaged temperature sensor to be tested on the uniform temperature platform;

[0053] S3: Fix the temperature distribution platform to the cold head of the Stirling refrigerator;

[0054] S4: Connect the temperature sensor to be measured to the vacuum penetration circuit board, and connect the standard temperature sensor to the vacuum penetration circuit board;

[0055] S5: Connect the temperature controller, temperature control board and vacuum penetration circuit board;

[0056] S6: Cover the uniform temperature platform with a radiation shield;

[0057] S7: Connect the flange top seat, Dewar cavity wall and flange base in sequence to form a sealed cavity;

[0058] S8: Install a vacuum detector at the vacuum interface and a vacuum gauge at the vacuum gauge interface;

[0059] S9: Use a vacuum detector to test the vacuum leakage rate of the sealed cavity. After the vacuum leakage rate test is qualified, remove the vacuum detector and install a vacuum pump at the vacuum port to evacuate the sealed cavity.

[0060] S10: Read the vacuum level inside the sealed cavity using a vacuum gauge. When the vacuum level inside the sealed cavity is lower than... The Stirling refrigerator is turned on for cooling.

[0061] S11: Set the operating temperature of the Stirling refrigerator cold head according to the temperature range to be calibrated. First, lower the operating temperature to the lowest temperature of the required calibration temperature range. When the temperature equalization platform is in a steady state, record the temperature difference between the temperature sensor under test and the standard temperature sensor. This temperature difference is used as the correction amount of the temperature sensor under test at that temperature. Then, increase the temperature according to a certain step size. When the temperature equalization platform is in a steady state, record the correction amount of the temperature sensor under test at each step temperature until the entire temperature range is calibrated.

[0062] S12: After calibration, remove the flange top seat and Dewar cavity wall to raise the cold head of the Stirling refrigerator to room temperature, and replace the position of the temperature sensor to be measured. Repeat S7 to S11.

[0063] S13: Take the average of the two corrections at each temperature point before and after the position swap as the final temperature correction.

[0064] Furthermore, in S1, the temperature sensor to be measured is a PT100 platinum resistance temperature sensor, and in S2, the standard temperature sensor is a Lakeshore temperature sensor with model number PT-103-AM-14L-QT.

[0065] Furthermore, in S1, the encapsulation of the temperature sensor under test refers to first soldering the temperature sensor under test onto the sensor pad, then leading the signal line of the temperature sensor under test into the signal line lead pad using a four-wire connection method and soldering it onto the signal line lead pad, then fixing the signal line through the signal line fixing pad, and finally connecting it to the vacuum penetration circuit board through the FPC cable to lead out the signal.

[0066] Furthermore, in S11, the steady state of the temperature equalization platform refers to the temperature stability of the cold head temperature monitoring point being within 10mK, and the temperature stability of the temperature sensor under test and the standard temperature sensor on the temperature equalization platform being within 8mK.

[0067] The specific method of using this invention is as follows:

[0068] First, the temperature sensor to be tested, namely the PT100 platinum resistance temperature sensor, is packaged. Then, the packaged temperature sensor to be tested and the standard temperature sensor are installed on a temperature-equalizing platform. Specifically, the temperature sensor to be tested is soldered onto the sensor pads, and the standard temperature sensor is attached to the platform using aluminum foil tape. The temperature-equalizing platform is then fixed to the cold head of the Stirling refrigerator using screws. Next, the standard temperature sensor and the temperature sensor to be tested are wired using a four-wire connection and connected to a vacuum penetration circuit board via an FPC cable to extract the signal. A radiation shield is then placed over the temperature-equalizing platform. Next, the flange top, Dewar cavity wall, and flange base are connected sequentially to form a sealed cavity. A vacuum detector is installed at the vacuum interface, and a vacuum gauge is installed at the vacuum gauge interface. After assembly, the vacuum leak rate of the sealed cavity is tested using the vacuum detector. Once the vacuum leak rate test is passed, the vacuum detector is removed, and a vacuum pump is installed at the vacuum extraction port to evacuate the sealed cavity. The vacuum level inside the sealed cavity is read using the vacuum gauge. When the vacuum level inside the sealed cavity is lower than a certain value, the vacuum leak rate is determined. The Stirling refrigerator is turned on for cooling. Then, the operating temperature of the Stirling refrigerator's cold head is set according to the required calibration temperature range. First, the operating temperature is lowered to the lowest temperature of the required calibration range. When the temperature plateau is in a steady state, the temperature difference between the temperature sensor under test and the standard temperature sensor is recorded. This temperature difference is used as the correction amount for the temperature sensor under test at that temperature. Then, the temperature is increased in steps. When the temperature plateau is in a steady state, the correction amount for the temperature sensor under test at each step temperature is recorded until the entire temperature range is calibrated. After the first calibration, the flange top and Dewar cavity wall are removed to allow the Stirling refrigerator's cold head to reach room temperature. The position of the temperature sensor under test is then changed. The above operation is repeated to perform a second calibration within the required calibration temperature range. Finally, the average of the two correction amounts at each temperature point before and after the position swap is taken as the final temperature correction amount.

[0069] The following explanation uses a set of temperature sensors under test as an example to illustrate the specific correction calculation. For example, the temperature range to be calibrated is -200℃ to -180℃, and the temperature increment is 1℃.

[0070] First, turn on the Stirling chiller and set its temperature to -210℃. Then, adjust the cold head temperature control according to the reading of the standard temperature sensor until the standard temperature sensor reading reaches -200℃. Next, when the temperature distribution platform is in a steady state, record the temperature of the standard temperature sensor using the temperature controller. Record the temperature of the sensor being measured as Then calculate and The difference between This serves as the correction value for the temperature sensor under test at -200℃. Then, the temperature is increased according to the set step size, and the correction value at each temperature point after the temperature increase is recorded sequentially until the temperature range is calibrated. At this point, the first calibration is completed.

[0071] Next, the position of the temperature sensor under test was changed so that the temperature reading of the standard temperature sensor dropped back to -200℃. Then, when the temperature equalization platform reached a steady state, the temperature of the standard temperature sensor was recorded by the temperature controller. Record the temperature of the sensor being measured as Then calculate and The difference between This serves as the correction value for the temperature sensor under test at -200℃. Then, the temperature is increased according to the set step size, and the correction value at each temperature point after the increase is recorded sequentially until the temperature range is calibrated. At this point, the second calibration is completed.

[0072] Finally, take The average value is used as the final correction amount at -200℃. The calculation method for the other temperature points is the same.

[0073] The beneficial effects of this invention are as follows:

[0074] 1) This invention uses a Stirling refrigerator to reduce the temperature to be measured to below -200℃. The standard Lakeshore temperature sensor has a wide temperature range with the lowest temperature reaching 17K, which makes the temperature sensor have a wide calibration temperature range down to -200℃.

[0075] 2) The Lakeshore temperature sensor used in this invention has its own temperature measurement characteristic curve and high temperature measurement accuracy; at the same time, the PT100 has the advantages of good thermal conductivity and accurate temperature measurement through the packaging method mentioned above, and the calibration accuracy can reach 10mk by calibrating by interchanged sensor positions.

[0076] 3) The area of ​​the temperature equalization platform of this invention is large enough to accommodate about 10 temperature sensors to be tested, which greatly improves the efficiency of sensor calibration and allows multiple temperature sensors to be calibrated at one time.

[0077] 4) The present invention has a small heat load, a fast cooling speed of the refrigerator, fewer operation steps, simple operation, and fast calibration time;

[0078] 5) The refrigeration unit and the penetrating circuit board of the present invention can be used repeatedly. Each time, only the temperature sensor to be measured needs to be replaced, and the device has a long service life.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A temperature sensor packaging and calibration apparatus, characterized by: The system includes a sealed cavity formed by a flange top seat (1), a Dewar cavity wall (2), and a flange base (3). The flange base (3) is welded with a refrigerator interface (31), a vacuum port (32), and a vacuum gauge interface (33) that communicate with the sealed cavity. A Stirling refrigerator (4) is installed at the refrigerator interface (31), and the cold head (41) of the Stirling refrigerator (4) is located within the sealed cavity. The system also includes a temperature equalization platform (5) connected to the cold head (41) of the Stirling refrigerator (4). The temperature equalization platform (5) is equipped with a standard temperature sensor (6) and an aluminum substrate (71). The aluminum substrate (71), the temperature sensor (7), the signal lead pad (72), the signal line fixing pad (73) are soldered on the substrate. The temperature sensor (7) to be tested is soldered on the sensor pad (74). The aluminum substrate (71), the temperature sensor (7), the signal lead pad (72), the signal line fixing pad (73) and the sensor pad (74) form the package structure of the temperature sensor (7). The flange base (3) is also provided with a vacuum penetration circuit board (8) connected to the standard temperature sensor (6) and the temperature sensor (7). The temperature sensor (7) to be tested is a PT100 platinum resistance temperature sensor.

2. The temperature sensor package and calibration apparatus of claim 1, wherein: Indium sheets are provided between the aluminum substrate (71) and the temperature equalization platform (5), between the standard temperature sensor (6) and the temperature equalization platform (5), and between the temperature equalization platform (5) and the cold head (41) of the Stirling refrigerator (4).

3. The temperature sensor package and calibration apparatus of claim 1, wherein: The temperature equalization platform (5) is a cylindrical copper block, and the surface of the temperature equalization platform (5) is polished. The temperature equalization platform (5) is provided with a radiation shield that cooperates with the temperature equalization platform (5), and the radiation shield is made of aluminum foil.

4. The temperature sensor packaging and calibration device according to claim 1, characterized in that: The flange top seat (1), the Dewar cavity wall (2) and the flange base (3) are all made of titanium alloy or Invar steel, and the processing accuracy of the flange top seat (1), the Dewar cavity wall (2) and the flange base (3) must reach the micron level. The Dewar cavity wall (2) is sealed with the flange base (3) and the flange top seat (1) respectively by rubber rings.

5. The temperature sensor packaging and calibration device according to claim 1, characterized in that: The signal line of the standard temperature sensor (6) is led out through the vacuum penetration circuit board (8) and connected to the external temperature controller. The signal line of the temperature sensor under test (7) is led out through the vacuum penetration circuit board (8) and connected to the external temperature control board. Both the standard temperature sensor (6) and the temperature sensor under test (7) adopt a four-wire connection method. Two sets of signal line lead pads (72) are set, and two sets of signal line fixing pads (73) are set. Each set of signal line fixing pads (73) consists of two parallel pads.

6. A temperature sensor packaging and calibration method according to any one of claims 1 to 5, comprising the following steps: S1: Encapsulate the temperature sensor to be measured; S2: Install the standard temperature sensor and the packaged temperature sensor to be tested on the uniform temperature platform; S3: Fix the temperature distribution platform to the cold head of the Stirling refrigerator; S4: Connect the temperature sensor to be measured to the vacuum penetration circuit board, and connect the standard temperature sensor to the vacuum penetration circuit board; S5: Connect the temperature controller, temperature control board and vacuum penetration circuit board; S6: Cover the uniform temperature platform with a radiation shield; S7: Connect the flange top seat, Dewar cavity wall and flange base in sequence to form a sealed cavity; S8: Install a vacuum detector at the vacuum interface and a vacuum gauge at the vacuum gauge interface; S9: Use a vacuum detector to test the vacuum leakage rate of the sealed cavity. After the vacuum leakage rate test is qualified, remove the vacuum detector and install a vacuum pump at the vacuum port to evacuate the sealed cavity. S10: The vacuum level inside the sealed cavity is read by a vacuum gauge. When the vacuum level inside the sealed cavity is lower than the specified value, the Stirling refrigerator is turned on to cool the cavity. S11: Set the operating temperature of the Stirling refrigerator cold head according to the temperature range to be calibrated. First, lower the operating temperature to the lowest temperature of the required calibration temperature range. When the temperature equalization platform is in a steady state, record the temperature difference between the temperature sensor under test and the standard temperature sensor. This temperature difference is used as the correction amount of the temperature sensor under test at that temperature. Then, increase the temperature according to a certain step size. When the temperature equalization platform is in a steady state, record the correction amount of the temperature sensor under test at each step temperature until the entire temperature range is calibrated. S12: After calibration, remove the flange top seat and Dewar cavity wall to raise the cold head of the Stirling refrigerator to room temperature, and replace the position of the temperature sensor to be measured. Repeat S7 to S11. S13: Take the average of the two corrections at each temperature point before and after the position swap as the final temperature correction.

7. The temperature sensor packaging and calibration method according to claim 6, characterized in that: In S1, the temperature sensor to be measured is a PT100 platinum resistance temperature sensor.

8. The temperature sensor packaging and calibration method according to claim 6, characterized in that: In S1, the encapsulation of the temperature sensor to be measured refers to first soldering the temperature sensor to be measured onto the sensor pad, then connecting the signal line of the temperature sensor to be measured to the signal line lead pad using a four-wire connection method, then fixing the signal line to the signal line fixing pad, and finally connecting the signal line to the vacuum penetration circuit board via an FPC cable to bring out the signal.

9. The temperature sensor packaging and calibration method according to claim 6, characterized in that: In S11, the steady state of the temperature equalization platform refers to the temperature stability of the cold head temperature monitoring point being within 10mK, and the temperature stability of the temperature sensor under test and the standard temperature sensor on the temperature equalization platform being within 8mK.

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