Cryostat and temperature control method thereof

Abstract

The invention provides a cryostat and a temperature control method thereof, and the cryostat comprises a vacuum cover which comprises a lower housing and an upper housing which are detachably connected; the cold shield comprises a first-stage cold cavity and a second-stage cold cavity which are tightly contacted from bottom to top; the cold shield is arranged in the vacuum cover; a placing table for bearing a to-be-tested product is arranged at the bottom in the second-stage cold cavity; and a refrigerating device for refrigerating the cold screen is arranged in the first-stage cold cavity. The vacuum cover is divided into the lower shell and the upper shell which are detachable, so that when a to-be-tested product is replaced, only the upper shell needs to be taken down, and the carrying weight is effectively reduced; the cold screen is divided into the first-stage cold cavity and the second-stage cold cavity, and the refrigerating device is placed in the first-stage cold cavity and refrigerates the second-stage cold cavity, so that the placing table in the second-stage cold cavity can accommodate more to-be-tested products, the temperature in the second-stage cold cavity cannot change suddenly, the to-be-tested products cannot be damaged, and the quality of the to-be-tested products is improved. The problem that the efficiency is low when a low-temperature thermostat is used for testing a photosensitive sensor chip in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature control equipment, and particularly relates to a cryostat and a temperature control method thereof. Background Art

[0002] A cryostat is a heat source or cold source device for heating / cooling or auxiliary heating / cooling, which can provide a thermally and cold-controlled, uniformly constant temperature field source for users during work, so as to realize the test or measurement of test samples or products to be produced in a constant temperature environment.

[0003] When testing a photosensitive sensor chip (such as an infrared photosensitive sensor chip), it is usually necessary to reduce the dark current generated by it in a low-temperature environment to ensure the reliability of the test results. Therefore, a cryostat is usually used to provide a low-temperature constant-temperature environment for the photosensitive sensor chip.

[0004] However, existing cryostats usually provide low temperatures based on 77K liquid nitrogen or 4.2K liquid helium, making the temperature unable to be adjusted flexibly; moreover, both the liquid nitrogen and liquid helium environments are transient conditions. When the photosensitive sensor chip is transferred from room temperature to a liquid nitrogen or liquid helium cryostat, it will be damaged due to its inability to withstand the temperature transient. In addition, when performing quantum tests, it is also necessary to provide a vacuum environment, a light source, a radiation black body, etc. In order for the cryostat to withstand the vacuum pressure, a vacuum cover of a certain weight needs to be installed, and it needs to be repeatedly disassembled and assembled when replacing the test sample, which is time-consuming and laborious; moreover, existing cryostats cannot provide an adjustable light source black body, resulting in inconvenient testing. Summary of the Invention

[0005] The purpose of the present invention is to provide a cryostat and a temperature control method thereof, so as to at least solve the problem of low efficiency when using a cryostat to test a photosensitive sensor chip.

[0006] To solve the above technical problems, the present invention provides a cryostat, including: A vacuum cover, including a lower shell and an upper shell that are detachably connected; A cold screen, including a primary cold cavity and a secondary cold cavity. The secondary cold cavity is placed above the primary cold cavity, and the lower surface of the secondary cold cavity is in close contact with the upper surface of the primary cold cavity; the cold screen is arranged inside the vacuum cover; a placement table is arranged at the bottom inside the secondary cold cavity, and the placement table is used to carry the product to be tested; a refrigeration device is arranged inside the primary cold cavity, and the refrigeration device is used to refrigerate the cold screen.

[0007] Optionally, in the cryostat, a detachable gasket is arranged between the lower shell and the upper shell; the lower shell and the upper shell are detachably connected by fasteners.

[0008] Optionally, in the cryostat, the vacuum chamber is provided with a first light-transmitting hole, the secondary cold cavity is provided with a second light-transmitting hole, and the vertical projection of the first light-transmitting hole at least partially falls on the second light-transmitting hole; a light source is installed on a side of the first light-transmitting hole away from the second light-transmitting hole, and the brightness and color of the light source are adjustable.

[0009] Optionally, in the cryostat, a first filter is installed in the first light-transmitting hole; a second filter is installed in the second light-transmitting hole.

[0010] Optionally, in the cryostat, the placement table is provided with a test port for communicatively connecting with the product to be tested; the primary cold cavity is provided with a first through hole and a second through hole, and the first through hole is located at the top of the primary cold cavity; a third through hole is provided at the bottom of the secondary cold cavity, and the third through hole is aligned with the first through hole; the vacuum chamber is provided with a fourth through hole; the test port is connected with a test wire, and the test wire is led out to the outside through the third through hole, the first through hole, the second through hole, and the fourth through hole in sequence.

[0011] Optionally, in the cryostat, the cryostat further includes an external controller; the placement table is provided with a temperature monitor and a heater communicatively connected with the external controller; the temperature monitor is used for monitoring the ambient temperature of the secondary cold cavity in real time and sending the monitored temperature to the external controller in real time; the external controller is used for controlling the degree of heating of the secondary cold cavity by the heater according to the temperature sent by the temperature monitor in real time so as to adjust the ambient temperature of the secondary cold cavity in real time.

[0012] Optionally, in the cryostat, the refrigeration device includes a refrigeration column and a plurality of heat conducting members; each heat conducting member is connected to the refrigeration column and the primary cold cavity.

[0013] Optionally, in the cryostat, the cryostat further includes a base, the lower housing is fixed to the base; the base is further fixed with a cold head, and the cold head is connected to the refrigeration device for refrigerating the refrigeration device.

[0014] Optionally, in the cryostat, a shock absorption mechanism is provided between the base and the vacuum chamber.

[0015] To solve the above technical problems, the present invention further provides a temperature control method applied to the cryostat as described in any one of the above, and the temperature control method includes: Setting a target temperature; Starting the refrigeration device to refrigerate the cold screen; Monitoring the ambient temperature of the secondary cold cavity in real time; If the ambient temperature of the secondary cold cavity reaches the target temperature, the refrigeration device is shut down.

[0016] Optionally, in the temperature control method described above, the temperature control method further includes: If the ambient temperature of the secondary cold cavity is higher than the target temperature, the refrigeration device is kept running until the ambient temperature of the secondary cold cavity reaches the target temperature; If the ambient temperature of the secondary cold cavity is lower than the target temperature, the refrigeration device is shut down and a heater is started to heat the secondary cold cavity until the ambient temperature of the secondary cold cavity reaches the target temperature, and then the heater is shut down.

[0017] The cryostat and its temperature control method provided by the present invention include: a vacuum chamber including a detachable lower housing and an upper housing; a cold shield including a primary cold cavity and a secondary cold cavity, the secondary cold cavity being disposed above the primary cold cavity and the lower surface of the secondary cold cavity being in close contact with the upper surface of the primary cold cavity; the cold shield is disposed within the vacuum chamber; a placement platform is provided at the bottom of the secondary cold cavity for carrying the product to be tested; a refrigeration device is provided within the primary cold cavity for cooling the cold shield. By dividing the vacuum chamber into a detachable lower housing and an upper housing, only the upper housing needs to be removed when replacing the product to be tested, effectively reducing the handling weight; by dividing the cold shield into a primary cold cavity and a secondary cold cavity, placing the refrigeration device in the primary cold cavity and cooling the secondary cold cavity not only enables the placement platform in the secondary cold cavity to accommodate more products to be tested, but also prevents the temperature in the secondary cold cavity from changing suddenly, ensuring that the products to be tested are not damaged, and solving the problem of low efficiency in testing photosensitive sensor chips using a cryostat. Description of the Drawings

[0018] Figure 1 Perspective view of the basic structure of the cryostat provided in this embodiment; Figure 2 Partial perspective view of the upper part of the cryostat provided in this embodiment; Figure 3 Partial perspective view of the cryostat at the placement platform provided in this embodiment; Figure 4 Schematic diagram of the surface structure of the placement platform provided in this embodiment; Figure 5 Schematic diagram of the overall structure of the cryostat provided in this embodiment; Figure 6 Flow chart of the temperature control method provided in this embodiment; Among them, the descriptions of the reference numerals are as follows: 100 - Vacuum cover; 101 - Lower housing; 102 - Upper housing; 103 - Fastener; 104 - First light - transmitting hole; 105 - First filter; 106 - Fourth through - hole 200 - Cold shield; 210 - Primary cold cavity; 211 - First through - hole; 212 - Second through - hole; 220 - Secondary cold cavity; 221 - Second light - transmitting hole; 222 - Second filter; 223 - Third through - hole; 230 - Refrigeration device; 231 - Refrigeration column; 232 - Heat - conducting member; 240 - Placing table; 241 - Test port; 242 - Temperature monitor; 243 - Heater 300 - Test wire; 400 - Base; 410 - Cold head; 420 - Shock - absorbing mechanism Detailed implementation manners

[0019] The following further elaborates on the cryostat and its temperature control method proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. It should be noted that the accompanying drawings are all in very simplified forms and use non - precise scales, only for conveniently and clearly assisting in explaining the purpose of the embodiments of the present invention. In addition, the structures shown in the accompanying drawings are often part of the actual structures. In particular, the focus points to be shown in each drawing are different, and sometimes different scales are used.

[0020] It should be noted that the "first", "second", etc. in the description, claims, and drawings of the present invention are used to distinguish similar objects, so as to describe the embodiments of the present invention, rather than to describe a specific order or sequence. It should be understood that such structures can be interchanged under appropriate circumstances. In addition, the terms "include" and "have" and any of their variations are intended to cover non - exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0021] This embodiment provides a cryostat, as Figure 1 shown, including: A vacuum cover 100, including a lower housing 101 and an upper housing 102 that are detachably connected; A cold shield 200, including a primary cold cavity 210 and a secondary cold cavity 220. The secondary cold cavity 220 is placed above the primary cold cavity 210, and the lower surface of the secondary cold cavity 220 is in close contact with the upper surface of the primary cold cavity 210. The cold shield 200 is disposed within the vacuum cover 100. A placing table 240 is provided at the bottom within the secondary cold cavity 220, and the placing table 240 is used to carry the product to be tested. A refrigeration device 230 is provided within the primary cold cavity 210, and the refrigeration device 230 is used to cool the cold shield 200.

[0022] The cryostat provided in this embodiment divides the vacuum chamber 100 into a detachable lower housing 101 and an upper housing 102, so that when replacing the product to be tested, only the upper housing 102 needs to be removed, effectively reducing the handling weight; by dividing the cold shield 200 into a primary cold chamber 210 and a secondary cold chamber 220, placing the refrigeration device 230 in the primary cold chamber 210 and refrigerating the secondary cold chamber 220, not only enables the placement table 240 in the secondary cold chamber 220 to accommodate more products to be tested, but also ensures that the temperature in the secondary cold chamber 240 does not change suddenly, guaranteeing that the products to be tested are not damaged, and solving the problem of low efficiency in testing photosensitive sensor chips using a cryostat in the prior art.

[0023] Specifically, in this embodiment, through the refrigeration of the refrigeration device 230, the ambient temperature of the primary cold chamber 210 can reach as low as 77K at the lowest, and the ambient temperature of the secondary cold chamber 220 can reach as low as 4K at the lowest, thus meeting the low-temperature test environment requirements of most products to be tested.

[0024] Furthermore, in order to ensure the sealing performance of the vacuum chamber 100 and thus have a good vacuum pumping capacity, in this embodiment, as Figure 1 shown, a detachable gasket (not shown in the figure) is provided between the lower housing 101 and the upper housing 102; the lower housing 101 and the upper housing 102 are detachably connected by fasteners 103.

[0025] In practical applications, a card slot is provided on the contact surface of the lower housing 101 and / or the upper housing 102, and the card slot is used to accommodate the gasket. To ensure the sealing performance between the lower housing 101 and the upper housing 102, the volume of the space formed by enclosing the card slot should be slightly smaller than the volume of the gasket, and the gasket should have a certain elasticity, so that after the lower housing 101 and the upper housing 102 are covered and fastened, the contact surface is sealed by the gasket. The gasket can specifically be a rubber ring.

[0026] Also, in practical applications, considering that there is a large pressure when the vacuum chamber 100 is evacuated, for safety and sealing considerations, a plurality of fasteners 103 can be provided within a suitable range of the contact surface between the lower housing 101 and the upper housing 102 to lock and fix the corresponding area. The fasteners 103 can be reasonably selected according to actual needs, such as screw and nut fixation, snap fixation, zip fixation, etc., and this application does not limit this.

[0027] Furthermore, in order to test the photosensitive sensor chip, a light source black body needs to be provided. In this embodiment, as Figure 2As shown, the vacuum cover 100 is provided with a first light-transmitting hole 104, and the secondary cold chamber 220 is provided with a second light-transmitting hole 221. The vertical projection of the first light-transmitting hole 104 at least partially falls on the second light-transmitting hole 221. A light source (not shown in the figure) is installed on the side of the first light-transmitting hole 104 away from the second light-transmitting hole 221. The brightness and color of the light source are adjustable.

[0028] In actual applications, considering that the test object is placed horizontally on the placement table 240 during testing, that is, the photosensitive surface of the test object is vertically facing upward, the first light transmission hole 104 can be opened on the top surface of the vacuum cover 100, that is, opened on the top surface of the upper shell 102; the second light transmission hole 221 can be opened on the top surface of the cold shield 200, that is, opened on the top surface of the secondary cold chamber 220. Of course, in actual applications, the opening positions of the first light transmission hole 104 and the second light transmission hole 221 can also be flexibly adjusted according to the placement position and photosensitive position of the test object.

[0029] Furthermore, in order to ensure that as much light as possible from the light source enters the secondary cold cavity 220, thereby ensuring sufficient light sensitivity for the product under test, in this embodiment, the first light-transmitting hole 104 and the second light-transmitting hole 221 can be coaxially arranged, and the aperture of the second light-transmitting hole 221 can be slightly larger than the first light-transmitting hole 104, thereby ensuring that light transmitted through the first light-transmitting hole 104 can completely enter the secondary cold cavity 220 through the second light-transmitting hole 221. The specific sizes of the first light-transmitting hole 104 and the second light-transmitting hole 221 can be reasonably set according to actual needs and are not limited in this application.

[0030] Considering the vacuuming requirements of the vacuum enclosure 100 and the cooling requirements of the cold shield 200, in this embodiment, the first light-transmitting hole 104 and the second light-transmitting hole 221 need to be sealed. Specifically, high-transmittance glass can be attached to the first light-transmitting hole 104 and the second light-transmitting hole 221, and a high-strength sealant can be used to seal the glass and the vacuum enclosure 100 or the cold shield 200.

[0031] Furthermore, in this embodiment, the light source can be placed at a preset distance from the top of the first light-transmitting hole 104 to ensure that as much light as possible from the light source enters the cold shield 200. The brightness, color, and fixing method of the light source can be reasonably set according to actual needs and will not be described in detail in this application.

[0032] Preferably, in order to avoid as much as possible the entry of ambient light into the cold shield 200 during the process of disassembling the light source during testing and debugging, thereby causing the ambient temperature of the secondary cold cavity 220 to rise, in this embodiment, a first filter 105 may be installed in the first light-transmitting hole 104, and / or a second filter 222 may be installed in the second light-transmitting hole 221.

[0033] In practical applications, considering that the infrared light has a relatively high temperature and is the main reason for the increase in the ambient temperature of the secondary cold cavity 220, the first filter 105 and the second filter 222 can adopt potassium bromide filters. Utilizing their characteristic that the filtration rate in the invisible infrared spectral band is greater than 90%, while reducing the temperature rise caused by ambient light entering the cold screen 200 when the light source blackbody is disassembled, it does not affect the transmission of the light source light during the normal test process, ensuring that the light source brightness in the secondary cold cavity 220 meets the requirements.

[0034] Furthermore, in this embodiment, as Figure 3 shown, the placement table 240 is provided with a test port 241, and the test port 241 is used for communicatively connecting with the product to be tested; the primary cold cavity 210 is provided with a first through hole 211 and a second through hole 212, and the first through hole 211 is located at the top of the primary cold cavity 210; the bottom of the secondary cold cavity 220 is provided with a third through hole 223, and the third through hole 223 is aligned with the first through hole 211; the vacuum cover 100 is provided with a fourth through hole 106; the test port 241 is connected to a test line 300, and the test line 300 is sequentially led out to the outside through the third through hole 223, the first through hole 211, the second through hole 212, and the fourth through hole 106.

[0035] In practical applications, for the convenience of leading out and fixing the test line 300, a guiding member can also be provided in the first cold cavity 210, so as to fix the test line 300 in the first cold cavity 210 through the guiding member.

[0036] Moreover, considering the vacuum pumping requirements of the vacuum cover 100 and the refrigeration requirements of the cold screen 200, in this embodiment, the first through hole 211, the second through hole 212, the third through hole 223, and the fourth through hole 106 opened need to be sealed. Specifically, after the test line 300 passes through the first through hole 211, the second through hole 212, the third through hole 223, and the fourth through hole 106, a high-strength sealant can be used for sealing and fixing, so that the sealing between the first through hole 211, the second through hole 212, the third through hole 223, the fourth through hole 106, and the test line 300 is complete.

[0037] Furthermore, in order to intelligently control the temperature of the cryostat, in this embodiment, the cryostat further includes an external controller; and, as Figure 4As shown, the placement table 240 is provided with a temperature monitor 242 and a heater 243 that are communicatively connected to the external controller; the temperature monitor 242 is used to monitor the ambient temperature of the secondary cold chamber 220 in real time and send the monitored temperature to the external controller in real time; the external controller is used to control the degree of heating of the secondary cold chamber 220 by the heater 243 in real time according to the temperature sent by the temperature monitor 242, so as to adjust the ambient temperature of the secondary cold chamber 220 in real time.

[0038] In practical applications, the external controller can be a host computer; the temperature monitor 242 and the heater 243 can be communicatively connected to the external controller through the test port 241 and the test line 300, or can be connected to the external controller in a wireless communication manner. Moreover, the layout positions, quantities, etc. of the temperature monitor 242 and the heater 243 can be set according to actual needs, and this application does not make any restrictions.

[0039] Further, in this embodiment, as Figure 3 shown, the refrigeration device includes a refrigeration column 231 and a plurality of heat conducting members 232; each of the heat conducting members 232 is connected to the refrigeration column 231 and the primary cold chamber 210.

[0040] In practical applications, the heat conducting member 232 can be a device with good heat conducting performance such as a metal sheet or a metal wire. In this way, by connecting the refrigeration column 231 and the primary cold chamber 210 through the heat conducting member 232, the primary cold chamber 210 can be refrigerated, and further, since the secondary cold chamber 220 is in close contact with the primary cold chamber 210, indirect refrigeration of the secondary cold chamber 220 is achieved.

[0041] Preferably, in this embodiment, as Figure 5 shown, the cryostat further includes a base 400, and the lower housing 101 is fixed to the base 400; the base 400 is further fixed with a cold head 410, and the cold head 410 is connected to the refrigeration device 230 and is used to refrigerate the refrigeration device 230.

[0042] In practical applications, when the cold head 410 is refrigerated based on liquid nitrogen or liquid helium, an on-off valve can be provided, and the on-off valve is controlled by the external controller to adjust the flow rate of liquid helium or liquid nitrogen, so as to adjust the refrigeration degree.

[0043] Moreover, considering the vacuum pumping requirement of the vacuum chamber 100, it is also necessary to use a high-strength sealant to seal and fix the joint of the refrigeration device 230 or the cold head 410 and the vacuum chamber 100.

[0044] More preferably, in order to provide a stable test environment and avoid deviation of test results caused by refrigeration of the cold head 410 or environmental vibration, in this embodiment, as Figure 5As shown, a shock-absorbing mechanism 420 is provided between the base 400 and the vacuum cover 100.

[0045] In practical applications, the shock-absorbing mechanism 420 can specifically be a shock-absorbing bellows.

[0046] Based on the cryostat provided in this embodiment, this embodiment also provides a temperature control method. As Figure 6 shown, the temperature control method includes: S1, set the target temperature.

[0047] Specifically, in this embodiment, the target temperature can be set through an external controller.

[0048] S2, start the refrigeration device to refrigerate the cold screen.

[0049] Specifically, in this embodiment, by controlling the external controller, the cold head 410 is started, and then the refrigeration device 230 is used to refrigerate the cold screen 200.

[0050] S3, monitor the ambient temperature of the secondary cold cavity in real time.

[0051] Specifically, in this embodiment, the ambient temperature of the secondary cold cavity 220 is monitored in real time by using the temperature monitor 242 arranged on the placement table 240.

[0052] S4, if the ambient temperature of the secondary cold cavity reaches the target temperature, turn off the refrigeration device.

[0053] Specifically, in this embodiment, the external controller obtains the ambient temperature monitored by the temperature monitor 242, and compares the obtained ambient temperature with the target temperature according to the internal program. If the ambient temperature is consistent with the target temperature, the cold head 410 is controlled to stop, thereby turning off the refrigeration device.

[0054] Preferably, considering that during the test process, the product to be tested needs to be adjusted at different temperatures, in order to flexibly adjust the ambient temperature in the secondary cold cavity, in this embodiment, the temperature control method further includes: S5, if the ambient temperature of the secondary cold cavity is higher than the target temperature, keep the refrigeration device started until the ambient temperature of the secondary cold cavity reaches the target temperature; S6, if the ambient temperature of the secondary cold cavity is lower than the target temperature, turn off the refrigeration device and start the heater to heat the secondary cold cavity until the ambient temperature of the secondary cold cavity reaches the target temperature, and then turn off the heater.

[0055] Specifically, in this embodiment, an external controller can be used to automatically control the heating process of the heater 243 located on the placement table 240, so that the working states of the heater 243 and the refrigeration device 230 can be flexibly adjusted in real time according to the temperature of the secondary cold chamber 220 monitored by the temperature monitor 242, enabling the temperature of the secondary cold chamber 220 to reach the target temperature.

[0056] In the actual application process, first, remove the fastener 103 between the lower housing 101 and the upper housing 102, and remove the upper housing 102; then, remove the cold shield housing of the secondary cold chamber 220 to expose the placement table 240; next, place the product to be tested on the placement table 240 and connect it to the test port 241; after that, replace the cold shield housing of the secondary cold chamber 220 to seal the secondary cold chamber 220; then, replace the upper housing 102, and use the fastener 103 to lock and fix the upper housing 102 to the lower housing 101.

[0057] After the installation is completed, evacuate the vacuum chamber 100, and set the target temperature in the external controller. The external controller automatically controls the cold head 410 to refrigerate the refrigeration device 230, and at the same time, the temperature monitor 242 transmits the temperature of the secondary cold chamber 220 to the external controller in real time. When the external controller determines that the temperature of the secondary cold chamber 220 transmitted back by the temperature monitor 242 reaches the target temperature, stop refrigerating. At this time, the light source can be turned on, and after the debugging of the light source is completed, the test of the product to be tested can be started.

[0058] After the test is completed at the current temperature, the target temperature can be changed, and the external controller automatically controls the cold head 410 to refrigerate the refrigeration device 230, or automatically controls the heater 243 to heat the secondary cold chamber 220. When the external controller determines that the temperature of the secondary cold chamber 220 transmitted back by the temperature monitor 242 reaches the target temperature, stop refrigerating or heating, and conduct the next test.

[0059] Considering that the product to be tested is easily damaged by sudden changes in the ambient temperature, during the test, the initial target temperature is first set to the lowest temperature required for the test, so as to use the refrigeration device 230 to refrigerate the secondary cold chamber 220 and gradually lower the temperature; and when adjusting the temperature, adjust in the order of temperature from low to high until the temperature before the end of the test is the highest temperature for the test.

[0060] After all the tests are completed, if the temperature difference between the secondary cold chamber 220 and the room temperature is large at this time, the heater 243 can be controlled to continue heating until the temperature difference between the secondary cold chamber 220 and the room temperature is small, and then open the vacuum valve to fill the vacuum chamber 100 with air. When the air pressure in the vacuum chamber 100 is the atmospheric pressure, remove the upper housing 102 and the cold shield housing of the secondary cold chamber 220, and replace the product to be tested to conduct the test on the next product to be tested.

[0061] The cryostat provided in this embodiment has a vacuum chamber 100 divided into a lower housing 101 and an upper housing 102. During testing, only the upper housing 102 needs to be taken, thus reducing the weight of the housing and facilitating operation by personnel. In the cryostat provided in this embodiment, since the cold shield 200 is divided into a first-stage cold chamber 210 and a second-stage cold chamber 220, the refrigeration device 230 in the first-stage cold chamber 210 is used to indirectly refrigerate the second-stage cold chamber 220, avoiding sudden temperature changes in the second-stage cold chamber 220. At the same time, the temperature in the second-stage cold chamber 220 is monitored by a temperature monitor, realizing intelligent adjustment of the refrigeration process. The heater in the second-stage cold chamber 220 is used to adjust the temperature increase of the second-stage cold chamber 220, thus realizing flexible and controllable temperature adjustment while avoiding damage to the product under test caused by sudden temperature changes. In the cryostat provided in this embodiment, by adding a first light-transmitting hole 104 and a first filter 105 at the vacuum chamber 100, and adding a second light-transmitting hole 221 and a second filter 222 at the cold shield 200, it is possible to effectively avoid temperature increase caused by ambient light during the light source debugging process, improve the temperature stability of the cold shield 200, and further ensure the reliability of the test results of the product under test.

[0062] It should be noted that the various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other. In addition, the different parts among the various embodiments can also be combined and used, and the present invention does not limit this.

[0063] The cryostat and its temperature control method provided in this embodiment include: a vacuum chamber including a lower housing and an upper housing that are detachably connected; a cold shield including a first-stage cold chamber and a second-stage cold chamber, the second-stage cold chamber is disposed above the first-stage cold chamber, and the lower surface of the second-stage cold chamber is in close contact with the upper surface of the first-stage cold chamber; the cold shield is disposed inside the vacuum chamber; a placement table is provided at the bottom inside the second-stage cold chamber, and the placement table is used to carry the product under test; a refrigeration device is provided inside the first-stage cold chamber, and the refrigeration device is used to refrigerate the cold shield. By dividing the vacuum chamber into a detachable lower housing and upper housing, only the upper housing needs to be removed when replacing the product under test, effectively reducing the handling weight. By dividing the cold shield into a first-stage cold chamber and a second-stage cold chamber, placing the refrigeration device in the first-stage cold chamber and refrigerating the second-stage cold chamber, not only enables the placement table in the second-stage cold chamber to accommodate more products under test, but also ensures that the temperature in the second-stage cold chamber does not change suddenly, guaranteeing that the product under test is not damaged, and solving the problem of low efficiency when using a cryostat to test a photosensitive sensor chip in the prior art.

[0064] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure are within the scope of protection of the claims.

Claims

1. A cryostat, characterized in that, Comprising: A vacuum chamber, including a lower housing and an upper housing detachably connected; A cold shield, including a first-stage cold cavity and a second-stage cold cavity, the second-stage cold cavity being disposed above the first-stage cold cavity, and the lower surface of the second-stage cold cavity being in close contact with the upper surface of the first-stage cold cavity; The cold shield is disposed within the vacuum chamber; A placement table is provided at the bottom within the second-stage cold cavity, and the placement table is used to carry the product to be tested; a refrigeration device is provided within the first-stage cold cavity, and the refrigeration device is used to refrigerate the cold shield.

2. The cryostat according to claim 1, characterized in that, A detachable gasket is provided between the lower housing and the upper housing; the lower housing and the upper housing are detachably connected by fasteners.

3. The cryostat according to claim 1, characterized in that, The vacuum chamber is provided with a first light-transmitting hole, and the second-stage cold cavity is provided with a second light-transmitting hole, and at least a part of the vertical projection of the first light-transmitting hole falls on the second light-transmitting hole; a light source is installed on a side of the first light-transmitting hole away from the second light-transmitting hole, and the brightness and color of the light source are adjustable.

4. The cryostat according to claim 3, characterized in that, A first filter is installed in the first light-transmitting hole; a second filter is installed in the second light-transmitting hole.

5. The cryostat according to claim 1, characterized in that, The placement table is provided with a test port, and the test port is used for communication connection with the product to be tested; the first-stage cold cavity is provided with a first through-hole and a second through-hole, and the first through-hole is located at the top of the first-stage cold cavity; a third through-hole is provided at the bottom of the second-stage cold cavity, and the third through-hole is aligned with the first through-hole; the vacuum chamber is provided with a fourth through-hole; the test port is connected with a test wire, and the test wire is led out to the outside through the third through-hole, the first through-hole, the second through-hole, and the fourth through-hole in sequence.

6. The cryostat according to claim 1, characterized in that, The cryostat further includes an external controller; the placement table is provided with a temperature monitor and a heater that communicate with the external controller; the temperature monitor is used to monitor the ambient temperature of the second-stage cold cavity in real time and send the monitored temperature to the external controller in real time; the external controller is used to control the degree of heating of the heater for the second-stage cold cavity in real time according to the temperature sent by the temperature monitor, so as to adjust the ambient temperature of the second-stage cold cavity in real time.

7. The cryostat according to claim 1, characterized in that, The refrigeration device includes a refrigeration column and a plurality of heat-conducting members; each heat-conducting member is connected to the refrigeration column and the first-stage cold cavity.

8. The cryostat according to claim 1, characterized in that, The cryostat further includes a base, the lower housing is fixed to the base; a cold head is further fixed to the base, and the cold head is connected to the refrigeration device and is used to refrigerate the refrigeration device.

9. The cryostat according to claim 1, characterized in that, A shock-absorbing mechanism is provided between the base and the vacuum chamber.

10. A temperature control method, applied to the cryostat according to any one of claims 1 to 9, characterized in that, The temperature control method includes: Setting a target temperature; Starting the refrigeration device to refrigerate the cold shield; Monitoring the ambient temperature of the second-stage cold cavity in real time; If the ambient temperature of the second-stage cold cavity reaches the target temperature, shutting down the refrigeration device.

11. The temperature control method according to claim 10, characterized in that, The temperature control method further includes: If the ambient temperature of the second-stage cold cavity is higher than the target temperature, keeping the refrigeration device started until the ambient temperature of the second-stage cold cavity reaches the target temperature; If the ambient temperature of the second-stage cold cavity is lower than the target temperature, shutting down the refrigeration device and starting the heater to heat the second-stage cold cavity until the ambient temperature of the second-stage cold cavity reaches the target temperature, and then shutting down the heater.

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