Miniaturized superconducting single photon detection system

Abstract

A miniaturized superconducting single photon detection system disclosed by the present invention comprises a system case, the case internally comprises a cold head and a compressor which are arranged in parallel, a detector electric control module located at one side of the cold head, and a compressor electric control module located at one side of the compressor, and the compressor and the compressor electric control module are integrated in a compressor shell. A plurality of groups of superconducting single-photon detectors are inversely hung on a sample disc of the cold head, the cryostat provides vacuum heat insulation and extremely low temperature installation conditions for the superconducting single-photon detectors, and the electric control module supplies power to the superconducting single-photon detectors and the refrigerating machine, monitors the state, controls the state and the like. Through ingenious space layout, anti-interference electric control design and one-way air cooling heat dissipation design, the problems of contradiction between ultralow temperature and strong heating, interference of strong dynamic electricity and extremely weak photon signals and the like are solved in a compact space; the ultra-low temperature high vacuum, complex electromagnetic environment and high signal-to-noise ratio read-out requirements of application of the superconducting single-photon detection technology can be met, meanwhile, a technical scheme is provided for achieving a miniaturized compact superconducting single-photon detection instrument, and the ultra-low temperature high vacuum superconducting single-photon detector can be applied to the fields of quantum information, biological imaging, environment monitoring, satellite-to-ground laser communication and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of single photon detection, and in particular to a miniaturized superconducting single photon detection system. Background Art

[0002] Since Einstein proposed the hypothesis of light quanta to explain the photoelectric effect in 1905, the concept of photons has promoted great progress in theoretical physics and experimental physics in many fields. The superconducting nanowire single photon detector (SNSPD) was first prepared by Gol'tsman et al. in 2000 based on the theoretical foundation of their predecessors. The superconducting nanowire single photon detector (SNSPD) is a single photon detector with excellent performance, which has the characteristics of high detection efficiency, low dark count, short dead time, etc. It can perform multiple photon detection within a range gate detection range, which can effectively improve the detection probability and detection signal-to-noise ratio, thereby improving the detection capability of the system.

[0003] The working mechanism of SNSPD is the phase transition from the superconducting state to the resistive state of superconducting nanowires triggered by a single photon. Its theoretical speed limit is determined by the thermal relaxation time and can reach up to tens of GHz. However, its nanowire structure determines that SNSPD has a large dynamic inductance. Therefore, in practical applications, the speed of SNSPD is generally determined by its dynamic inductance. The typical SNSPD is a meandering wire structure, and the photon response speed is about 10Mcps (counts per second). At present, many international scientific research organizations are actively carrying out research on large-array SNSPDs with high efficiency, high speed and high resolution, and use its high efficiency to meet the requirements of accurate detection of the quantum state of photons transmitted in the channel in the information field, especially in quantum key distribution technology, so as to ensure the absolute security of communication.

[0004] One of the key technical indicators is a higher photon response speed. Recently, with further research on high-speed SNSPD, a multimode fiber-coupled superconducting nanowire single-photon detector has emerged, which not only expands the detector's photosensitive surface but also increases the detector's count rate. Using 16 fully wound nanowire arrays, the detector as a whole has achieved a system detection efficiency (SDE) of more than 50% and a maximum count rate of 3.1Gcps, as well as a count rate of 1.3Gcps when the efficiency drops by half.

[0005] With the rapid development of applications such as long-distance laser ranging, higher requirements have been gradually placed on the system performance of SNSPD. The key to promoting applications is to develop miniaturized detection systems. In terms of portability, the combination of a miniaturized SNSPD detector system and a laser ranging system makes the structural layout of the entire large system lighter, easier to install and transport. In terms of integration, a miniaturized SNSPD detector system generally adopts a highly integrated module design, and the device can be replaced at any time in the event of a device failure. The energy consumption of the miniaturized detection system is designed to be low, which reduces the power consumption of the equipment and solves the dependence of the detector system on high-power power supplies as a ground-based payload, air-based payload, and quantum communication network.

[0006] The following difficulties exist in the integration process of miniaturized detection systems: a. Low operating temperature, complex cryogenic system and vacuum system, making miniaturization difficult; b. Weak signal and strong interference lead to difficulty in electromagnetic compatibility. The working environment of SNSPD requires the temperature to be below the superconducting transition temperature of its material, which makes the technical requirements of the peripheral cryogenic system high and the vacuum environment harsh. To this end, a cryogenic system with large weight and volume must be used to work together, and an ultra-high vacuum pump is also required to create a vacuum environment, which makes it difficult to miniaturize the system. At the same time, the system's cryogenic refrigerator and vacuum pump and other inductive loads generate more electromagnetic interference in the system's power grid environment, which increases the difficulty of extracting single photons with an original signal of only μV. The signal-to-noise ratio is low due to strong external electrical interference. The miniaturized system must not only solve the optimization of the system structure, but also solve complex electromagnetic compatibility issues.

[0007] Common miniaturized ultra-low temperature refrigeration technologies include liquid helium dewars, Stirling refrigerators, and GM refrigerators. Liquid helium dewars generally use liquid helium and liquid nitrogen as cold sources. The temperature of the sample stage can only be maintained at a minimum of 4K for dozens of hours. Once the cold source is consumed, the temperature cannot be sustained. To achieve lower temperatures, a vacuum pump is required to extract the vacuum degree of the liquid helium cavity. The temperature of the sample stage can be as low as 2K, but it can usually only be maintained for a few hours. The Stirling refrigerator is a refrigeration device based on the Stirling cycle, which achieves refrigeration through the compression and expansion of gas. The Stirling refrigerator can reach moderately low temperatures, usually between 10K and 100K, and is suitable for applications that require moderately low temperatures. It cannot meet the temperature requirements of superconducting single-photon detectors.

[0008] GM refrigerator achieves refrigeration by compressing and expanding gas, and is composed of independent compression system and refrigeration system. The compression system includes: reciprocating compressor, high and low pressure chambers, cooler and purifier, etc. The refrigeration system is composed of expander, cold storage device and transmission mechanism. GM refrigerator can usually reach a temperature below 4K, which is a common cold source in industry and can always provide cooling capacity. The compression system and refrigeration system are usually called compressor and cold head respectively. Among them, the cold head part usually adds additional vacuum design and heat sink design to facilitate the installation and interconnection with samples for practical applications. The development of miniaturized superconducting single-photon detection system using small GM refrigerator has the advantages of stable performance and low cost, but the small GM refrigerator system that can reach below 3K usually includes a compressor and a cold head, and the height after stacking exceeds one meter, which is difficult to miniaturize. Summary of the invention

[0009] Purpose of the invention: The purpose of the present invention is to provide a miniaturized superconducting single-photon detection system that integrates a refrigerator, a cryostat, an electronic control module, etc.

[0010] Technical solution: To achieve the above-mentioned purpose, the miniaturized superconducting single-photon detection system described in the present invention includes a system chassis, and the components inside the chassis include a compactly placed electronic control module, a superconducting detector, a cold head and a compressor of a refrigerator, and a thermostat. The compressor is a square narrow and long structure, and the thermostat is an elliptical narrow and long structure. The cold head and the thermostat are arranged on one side of the compressor, and multiple groups of superconducting single-photon detectors are installed between the first-level cold stage and the second-level cold stage of the cold head; the electronic control module includes a detector electronic control module located on one side of the cold head and a compressor electronic control module located on one side of the compressor. The detector electronic control module and the compressor electronic control module are located on the same side in the chassis, and the detector electronic control module adopts a spatial electromagnetic shielding structure design.

[0011] Wherein, the front and back sides of the secondary cold stage are both provided with thermal resistance layers, wherein the back side is provided with a superconducting detector mounting base through a high thermal conductivity fixing plate and a reverse suspension connecting machine, and a sample tray is placed on the front side.

[0012] The first-stage cold stage and the second-stage cold stage are located in a thermostat, wherein a heat shielding cover including the sample tray is covered above the first-stage cold stage, and space is reserved in the direction of the elliptical major axis in the thermostat for installing a superconducting detector.

[0013] Wherein, a thermometer is also arranged at the sample tray, and is connected to an external monitoring device via a temperature control interface.

[0014] Among them, the thermostat is also provided with a vacuum cover, and various interfaces are arranged along the major axis direction of the ellipse, including a vacuum adapter, an SMA adapter, an SMA outlet, and a spare interface.

[0015] The overall dimensions of the thermostat are: 250-300mm in length, 150-250mm in width, and 450-500mm in height.

[0016] The compressor includes a horizontal press package at the bottom layer, and an electric control box, a buffer tank, an oil separator, an adsorber, a fan and an air-cooled heat exchanger arranged in sequence at the upper layer of the horizontal press package. The overall dimensions of the compressor are: 500-550mm in length, 2500-300mm in width, and 450-500mm in height.

[0017] Among them, the detector electronic control module includes a high-isolation power supply submodule, a small signal amplification submodule, a control circuit submodule, and a space electromagnetic shielding structure; among them, the high-isolation power supply submodule is used to solve the interference of electromagnetic noise brought by high-power refrigeration equipment on small signal amplification; the control circuit submodule and the small signal amplification submodule adopt a stacked layout in structure to reduce the volume while realizing four-way signal readout control, and the control circuit module realizes multi-module control and can simultaneously control the readout of 16-unit superconducting single-photon detectors; the space electromagnetic shielding structure is divided into an upper and lower two-layer structure, the upper layer is placed with a four-way signal readout module, and the lower layer is placed with a control circuit module. The connection between the modules adopts a through-wall capacitor connector to shield noise.

[0018] The detector electronic control module includes a display, a main controller, a power manager, a signal controller, and a signal processor which are fixed in the housing of the detector electronic control module through fixing ears.

[0019] Among them, the compressor and the compressor electronic control module are integrated in the compressor housing, the compressor housing is provided with a heat dissipation air duct, and the outer ring of the compressor housing is also provided with a heat dissipation net. The ventilation and heat dissipation sequence is: cold head, compressor, heat dissipation net, detector electronic control, compressor, heat dissipation net, compressor electronic control module, compressor, heat dissipation net, three-way parallel ventilation and heat dissipation; the compressor housing has heat dissipation and electromagnetic shielding functions, and overcomes the interference of weak signals of superconducting detectors by the common ground design of the whole machine and the isolation of strong and weak electricity.

[0020] Beneficial effects: The present invention has the following advantages:

[0021] 1. The present invention is based on a small GM refrigerator. Through ingenious thermoelectric design and spatial layout, it solves the miniaturization problem of ultra-low temperature systems, greatly reduces the size of superconducting single-photon detection systems, and realizes miniaturized whole-machine system integration of superconducting devices, cryogenic modules, and electronic control modules. It has broad application prospects in the fields of quantum information, environmental monitoring, biomedicine, laser communication, etc.

[0022] 2. The system can achieve a height of no more than 0.5 meters. The overall dimensions of the thermostat are 250-300mm in length, 150-250mm in width, and 450-500mm in height. The overall dimensions of the compressor are 500-550mm in length, 2500-300mm in width, and 450-500mm in height. At the same time, it is compatible with the installation of up to 16 superconducting single-photon detectors, and the working band covers all bands from ultraviolet to mid-wave infrared;

[0023] 3. The superconducting single-photon detector is installed upside down in the upper part of the cryostat, making full use of the space of the first and second cold stages and reducing the height of the entire system;

[0024] 4. The heat sink structure of the secondary cold stage is vertically transmitted from the cold head to the thin low thermal conductivity layer and the high thermal conductivity layer, then horizontally transmitted to the side through the high thermal conductivity layer, and then connected to the space between the primary and secondary cold stages through high thermal conductivity, which fully utilizes the space between the primary and secondary cold stages while ensuring good thermal conductivity and temperature stability;

[0025] 5. The compressor shell is designed in layers to make full use of limited space to achieve compact design, reducing the overall volume of the compressor by 10%. It has the characteristics of high aspect ratio, which is convenient for parallel layout with the low-temperature thermostat where the cold head is located. At the same time, it can also be isolated from the installation position of the vibration source, reducing the vibration level of the entire equipment;

[0026] 6. The compressor housing is provided with a heat dissipation air duct opening, which allows air to enter from the side of the lower layer of the pressure pack and exit from the side of the upper layer of the air-cooled heat exchanger, forming an air duct that runs through the entire internal space of the housing, avoiding the problem of local overheating and improving the heat dissipation efficiency and stability of the compressor;

[0027] 7. The electronic control modules of the compressor and detector are located in front of the cold head and compressor respectively, and the interconnection distance is short, which can minimize external noise interference and improve the signal-to-noise ratio of the detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall layout of a miniaturized superconducting single-photon detection system;

[0029] Figure 2 It is a schematic diagram of the internal layout of the compressor housing;

[0030] Figure 3 It is the three-view drawing of the internal layout of the compressor housing;

[0031] Figure 4 It is a schematic diagram of the cold head structure;

[0032] Figure 5 Schematic diagram of the layout of the detector's electronic control module;

[0033] Figure 6This is the appearance diagram of the miniaturized superconducting single-photon detection system. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is described in detail below in conjunction with the embodiments and drawings.

[0035] The miniaturized superconducting single-photon detection system described in the present invention includes a system chassis, which includes a low-temperature thermostat, a refrigerator, and an electronic control module; the refrigerator includes a compressor and a cold head, and performs circulating refrigeration through a refrigerant (such as helium). The cold head body is located in the low-temperature thermostat, and as a key component for heat exchange, it utilizes the circulating flow of the refrigerant to absorb the heat of the cooled object to achieve refrigeration; the low-temperature thermostat provides vacuum insulation and extremely low-temperature installation conditions for the superconducting single-photon detector, and the electronic control module provides power, status monitoring, and status control for the superconducting single-photon detector and the refrigerator.

[0036] like Figure 1 As shown in the figure, it is a schematic diagram of the overall layout of the miniaturized superconducting single-photon detection system, including a cold head 1 and a compressor 2 arranged in parallel, as well as a detector electronic control module 3 located on one side of the cold head 1 and a compressor electronic control module 4 located on one side of the compressor 2. The compressor 2 and the compressor electronic control module 4 are integrated in the compressor housing. This layout is comprehensively designed based on the requirements of component size, heat dissipation and noise, achieving compactness, good heat dissipation and anti-electromagnetic interference, which are specifically manifested as follows:

[0037] (1) The housing in which the compressor 2 and the compressor electronic control module 4 are integrated and the low-temperature thermostat in which the cold head 1 is located are arranged in parallel, which minimizes the size and helps to optimize the use of the chassis space;

[0038] (2) Through airflow design, the compatibility between the high-heat module (such as compressor 2) and the ultra-low-temperature module (the cryostat where the cold head 1 is located) is solved to maintain the stability of the internal temperature of the system;

[0039] (3) The compressor electronic control module 4 is located on one side of the compressor housing, and the detector electronic control module 3 connected to the superconducting single photon is located on one side of the low-temperature thermostat in the chassis. The interconnection distance between the two electronic control modules is short, which can minimize external noise interference and improve the detector signal-to-noise ratio.

[0040] The characteristic of the above-mentioned parallel vertical layout is that the cold head 1 and the compressor 2 are in the same plane and arranged side by side, which effectively reduces the height difference between the bottom and the top.

[0041] like Figure 2 , 3As shown in the figure, the internal layout of the compressor housing is schematically shown. The housing is divided into two layers, the upper and lower layers, to achieve efficient arrangement of equipment and space optimization. The bottom layer is a horizontal pressure pack 2.1, and the upper layer is an electric control box 2.2, a buffer tank 2.3, an oil separator 2.4, an adsorber 2.5, a fan 2.6, and an air-cooled heat exchanger 2.7, which are arranged compactly in sequence. The various devices in the housing are connected through independent oil and gas systems, ensuring the coordinated work of the various devices and the stable operation of the system.

[0042] The compressor as a whole adopts a high aspect ratio layout, which is conducive to the parallel layout with the low-temperature thermostat, while reducing the floor space. At the same time, a vertical structural design is adopted to combine the horizontal pressure package 2.1, air-cooled heat exchanger 2.7, oil separator 2.4 and other structures in layers, making full use of limited space to achieve compact design, so that the overall volume of the compressor 2 is reduced by 10% compared with the existing compressor, and has a high aspect ratio, which is convenient for parallel layout with the low-temperature thermostat. The horizontal pressure package 2.1 of the moving component is further arranged in the lower layer, and the static components including the electronic control module 4, oil separator 2.4, buffer tank 2.3, and air-cooled heat exchanger 2.7 are arranged in the upper layer, isolated from the vibration source installation position, reducing the overall vibration level of the compressor 2.

[0043] In addition, a heat dissipation air duct is provided on the shell, that is, air enters from one side of the lower pressure package and exhausts from one side of the upper air-cooled heat exchanger 2.7, forming an air duct that runs through the entire internal space of the shell, which helps to dissipate heat from the pressure package 2.1, avoids local overheating problems, and improves the heat dissipation efficiency and stability of the compressor 2.

[0044] The working principle of the compressor is as follows: the low-temperature and low-pressure helium discharged from the cold head 1 passes through the buffer tank 2.3 and is sucked into the pressure pack 2.1. First, it is compressed by the vortex disk in the compression chamber of the pressure pack 2.1 to produce a high-temperature and high-pressure oil-gas mixture. The oil-gas mixture is separated from most of the oil and helium in the pressure pack 2.1 by impact and gravity. The separated oil is cooled by the air-cooled heat exchanger 2.7 and then sprayed into the tail of the pressure pack 2.1. The fan 2.6 takes the heat out of the system. The helium separated from the pressure pack 2.1 is cooled by the air-cooled heat exchanger 2.7 and enters the oil separator 2.4 to further separate most of the oil and gas. The separated oil is filtered and throttled and then injected into the low-pressure chamber of the pressure pack 2.1. The separated helium enters the adsorber 2.5 to further adsorb the oil molecules in the helium. The high-purity and high-pressure helium after adsorption is provided to the cold head of the refrigerator. After the adsorber 2.5 is saturated with adsorption, it needs to be replaced and maintained regularly.

[0045] like Figure 4The figure shows a schematic diagram of the cold head structure inside the cryostat, which includes two-stage cold plates (primary cold stage and secondary cold stage), a mounting base and a shielding cover. This design uses a compact layout to ensure the internal use space while minimizing the external dimensions as much as possible, achieving the goals of miniaturization, convenience and lightness. Specifically, it includes: lower fixed plate 1.1.1, GM cold head 1.2, temperature control interface 1.3, vacuum adapter 1.4, primary cold stage 1.5, vacuum cover 1.6, thermometer 1.7, thermal resistance layer 1.8, sample tray 1.9, superconducting single photon detector 1.10, SMA adapter 1.11, SMA outlet 1.12, spare interface 1.13, support column 1.14, secondary cold stage 1.15.

[0046] The GM cold head 1.2 is an inverted structure. The GM cold head 1.2 connector is fixed on the upper fixing plate, and the upper fixing plate is fixed on the lower fixing plate 1.1 through four support columns 1.14. This structure provides stable support for the GM cold head 1.2 body located inside the cryostat, and may also help reduce the impact of vibration on the GM cold head 1.2. The GM cold head 1.2 connector is connected to the compressor to inhale high-purity and high-pressure helium to provide an extremely low temperature environment for the sample tray 1.9 at the upper end of the GM cold head 1.2 body. The GM cold head 1.2 body includes two-stage cold plates, of which the first-stage cold stage 1.5 can be used as a system radiation screen, and a heat shielding cover including the sample tray 1.9 is provided above to reduce the radiation impact of the vacuum cover 1.6 covering the outside of the GM cold head 1.2 body on the sample tray 1.9.

[0047] The sample tray 1.9 is located above the secondary cold stage. In order to increase the heat conduction efficiency between the secondary cold stage and the sample tray 1.9 and improve the temperature uniformity of the sample tray 1.9, a thermal resistance layer 1.8 is provided between the sample tray 1.9 and the secondary cold stage, thereby effectively suppressing the temperature fluctuation of the sample tray 1.9. In addition, indium metal is coated between the sample tray 1.9, the thermal resistance layer 1.8 and the secondary cold stage, further improving the heat conduction performance. The sample tray 1.9 is made of a metal material with high thermal conductivity, and its diameter and thickness are both greater than the thermal resistance layer 1.8. The thermal resistance layer 1.8 is a metal material with low thermal conductivity, which ensures that the sample tray 1.9 can dissipate heat evenly and quickly and maintain a stable low-temperature environment.

[0048] The superconducting single-photon detector 1.10 is hung upside down on the circumference of the lower surface of the sample tray 1.9, further reducing the space requirement above the sample tray 1.9. The heat generated during the detection process is quickly transferred to the secondary cold stage through the sample tray 1.9 and the thermal resistance layer 1.8, and is finally discharged by the refrigerator, ensuring that the superconducting single-photon detector 1.10 works normally in a stable low-temperature environment.

[0049] A thermometer 1.7 is also provided at the sample tray 1.9. The temperature control changes can be monitored in real time on the external device through the temperature control interface 1.3. The vacuum feedthrough optical fiber enters the low-temperature thermostat through the vacuum adapter 1.4 and is connected to the superconducting single-photon detector 1.10. The superconducting single-photon detector 1.10 is installed under the sample tray and connected to the SMA adapter 1.11. The signal is output to the SMA outlet 1.12 through the low-temperature RF cable. Before running the system, the external vacuum pump group needs to evacuate the inside of the vacuum cover 1.6 through the vacuum adapter 1.4 to provide a vacuum environment for the system. In addition, the vacuum cover 1.6 is provided with an SMA adapter 1.11 inside and an SMA outlet 1.12 outside for testing. The spare interface 1.13 can be used to expand the interface to meet experimental needs.

[0050] like Figure 5 The figure shows a simplified structure diagram of the electric control module. The electric control module 3 of the compact detector mainly includes: a display 3.1, a main controller 3.2, a power manager 3.3, a signal controller 3.4, a signal processor 3.5, and a fixing ear 3.6. The compact and modular design minimizes the external dimensions as much as possible while ensuring the circuit function and electromagnetic compatibility. By utilizing the limited control of the system, an expandable panel is designed on the front of the device, and the various parts of the electric control module can be freely matched, so as to realize the installation and signal processing of superconducting single-photon detectors of different numbers and functions, so as to achieve miniaturization, convenience, lightness, and modular design.

[0051] The communication between modules adopts RS485 protocol. The main controller 3.2 is used as the host module to complete the data processing of the low temperature sensor and the air pressure sensor and the display task of the display 3.1. The display 3.1 adopts a touch display and can control the working status of each part of the superconducting single photon detector system. The power manager 3.3 is designed with a high isolation control method to realize the control of the vacuum pump, solenoid valve, and refrigerator in the system, and completes the logical control of each part of the system through the main controller 3.2. The signal controller 3.4 and the signal processor 3.5 are the superconducting single photon detector readout modules. Signal control and processing can realize the diversification of the detector output signal mode and the multi-channel function of the superconducting single photon detector. The fixed ears 3.6 are designed on different electric control modules, and the fixed spacing is designed to be the same, which can realize the interchange and interconnection between the modules. Each module is designed as a miniaturized pluggable board structure, which is easy to integrate within the system.

[0052] The detector electronic control module 3 optimizes the mutual interference between small signal amplification and high-power refrigeration through electromagnetic compatibility and space shielding. The designed superconducting single-photon detector readout module mainly includes a high-isolation power submodule, a small signal amplification submodule, a control circuit submodule, and a space electromagnetic shielding structure. The high-isolation power submodule can solve the interference of electromagnetic noise caused by high-power refrigeration equipment on small signal amplification. The control circuit submodule and the small signal amplification submodule adopt a stacked layout in structure, which can realize four-way signal readout control while reducing the volume. The control circuit module realizes multi-module control and can control the readout of 16 units of superconducting single-photon detectors at the same time. The space electromagnetic shielding structure is mainly divided into an upper and lower structure. The upper layer is placed with a four-way signal readout module, and the lower layer is placed with a control circuit module. The connection between the modules adopts a through-wall capacitor connector to shield noise.

[0053] like Figure 6 The figure shows the appearance of the whole machine of the miniaturized superconducting single-photon detection system, which includes the compressor and cold head of the refrigerator, superconducting single-photon detectors, and electronic control modules. The compressor and cold head obtain ultra-low temperature environment, and the cryostat of the cold head provides vacuum insulation and superconducting device installation conditions. The electronic control module provides power supply, status monitoring and status control for superconducting devices and refrigerators. The design uses a compact compressor structure with a high aspect ratio layout. Through clever thermoelectric design and spatial layout, it solves the miniaturization problem of the ultra-low temperature system, so that the cryostat part can be arranged in parallel with the compressor. The height of the whole machine does not exceed 0.5 meters, and it is compatible with up to 16 superconducting single-photon detectors. The working band ranges from ultraviolet to mid-wave infrared, which greatly reduces the size of the superconducting single-photon detection system and realizes the miniaturized whole machine system integration of superconducting devices, cryogenic modules and electronic control modules. It has broad application prospects in quantum information, environmental monitoring, biomedicine and laser communication.

[0054] The superconducting single-photon detector 1.10 is installed upside down at the upper end of the cryostat, making full use of the space of the primary and secondary cold stages and reducing the height of the entire cryostat. The heat sink structure of the secondary cold stage is vertically from the cold head to the thin low thermal conductivity layer and the high thermal conductivity layer, then horizontally transmitted to the side through the high thermal conductivity layer, and then connected to the space between the primary and secondary cold stages through high thermal conductivity. The clever structural design ensures good thermal conductivity and temperature stability at the same time, and also has the characteristics of high space utilization.

Claims

1. A miniaturized superconducting single photon detection system, including a system chassis, characterized in that: The components inside the chassis include a compactly placed electronic control module, a superconducting detector, a cold head and compressor of a refrigerator, and a thermostat. The compressor is a square narrow and long structure, the thermostat is an elliptical narrow and long structure, the cold head and the thermostat are arranged on one side of the compressor, and multiple groups of superconducting single-photon detectors are installed between the primary cold stage and the secondary cold stage of the cold head; the electronic control module includes a detector electronic control module located on one side of the cold head and a compressor electronic control module located on one side of the compressor. The detector electronic control module and the compressor electronic control module are located on the same side inside the chassis, and the detector electronic control module adopts a spatial electromagnetic shielding structure design.

2. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The front and back sides of the secondary cold stage are both provided with thermal resistance layers, wherein the back side is provided with a superconducting detector mounting base through a high thermal conductivity fixing plate and a reverse suspension connecting machine, and a sample tray is placed on the front side.

3. The miniaturized superconducting single-photon detection system according to claim 2, characterized in that: The primary cold stage and the secondary cold stage are located in a thermostat, wherein a heat shielding cover including the sample tray is covered on the primary cold stage, and a space is reserved in the thermostat in the direction of the elliptical major axis for installing a superconducting detector.

4. The miniaturized superconducting single-photon detection system according to claim 2, characterized in that: The sample tray is also provided with a thermometer, and is connected to an external monitoring device via a temperature control interface.

5. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The thermostat is also provided with a vacuum cover, and various interfaces are provided along the major axis direction of the ellipse, including a vacuum adapter, an SMA adapter, an SMA wire outlet, and a spare interface.

6. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The overall dimensions of the thermostat are: 250-300 mm in length, 150-250 mm in width, and 450-500 mm in height.

7. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The compressor includes a horizontal press package located at the bottom layer, and an electric control box, a buffer tank, an oil separator, an adsorber, a fan and an air-cooled heat exchanger located at the upper layer of the horizontal press package and arranged in sequence. The overall dimensions of the compressor are: 500-550mm in length, 2500-300mm in width, and 450-500mm in height.

8. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The detector electronic control module includes a high-isolation power supply submodule, a small signal amplification submodule, a control circuit submodule, and a space electromagnetic shielding structure; wherein the high-isolation power supply submodule is used to solve the interference of electromagnetic noise brought by high-power refrigeration equipment on small signal amplification; the control circuit submodule and the small signal amplification submodule adopt a stacked layout in structure, which reduces the volume while realizing four-way signal readout control, and the control circuit module realizes multi-module control and can simultaneously control the readout of 16-unit superconducting single-photon detectors; the space electromagnetic shielding structure is divided into an upper and lower two-layer structure, the upper layer is placed with a four-way signal readout module, and the lower layer is placed with a control circuit module, and the connection between the modules adopts a through-wall capacitor connector to shield noise.

9. The miniaturized superconducting single-photon detection system according to claim 8, characterized in that: The detector electronic control module comprises a display, a main controller, a power manager, a signal controller and a signal processor which are fixed in a housing of the detector electronic control module through fixing ears.

10. The miniaturized superconducting single-photon detection system according to claim 1, characterized in that: The compressor and the compressor electronic control module are integrated in the compressor housing. The compressor housing is provided with a heat dissipation air duct opening, and the outer ring of the compressor housing is also provided with a heat dissipation net. The ventilation and heat dissipation sequence is: cold head, compressor, heat dissipation net, detector electronic control, compressor, heat dissipation net, compressor electronic control module, compressor, heat dissipation net, three-way parallel ventilation and heat dissipation; the compressor housing has heat dissipation and electromagnetic shielding functions, and overcomes the interference of weak signals of superconducting detectors by the common ground design of the whole machine and the isolation of strong and weak electricity respectively.

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