A detector vacuum packaging device for low-noise readout

Abstract

The present invention relates to vacuum and low-temperature packaging technology for detectors and discloses a detector vacuum packaging device for low-noise readout. The device is suitable for scenarios where vacuum and low-temperature packaging of detectors and low-noise electronic readout are required, and is particularly suitable for detectors with relatively large single target surfaces. The device adopts a thermal control-related detector cooling and thermal radiation shielding solution, and incorporates an electronic preamplifier related to the low-noise readout technology into the device, thereby reducing readout noise and heat exchange with the outside world.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum and low-temperature packaging of detectors, and in particular to a detector vacuum packaging device for low-noise readout. Background Art

[0002] In scientific-grade detector applications, achieving optimal performance typically requires cooling the detector to extremely low temperatures. Heat transfer occurs primarily through conduction, convection, and radiation. The combined effects of these three factors must be considered in the design of detector packaging and thermal control solutions.

[0003] Convective heat transfer is a significant factor limiting detector cooling. Temperature differences cause fluids to flow relative to each other, creating a direct heat exchange between the surrounding environment and the detector. Furthermore, the influence of thermal radiation is also significant. The thermal power of thermal radiation is directly related to the material's emissivity. Commonly used materials for semiconductor detector packaging, such as SiC, ceramics, and plastics, can have emissivities of 0.7 or even higher. Convection and thermal radiation significantly impact detector cooling time and power. Therefore, when designing a detector thermal control solution, consideration must be given to vacuum packaging and shielding the detector from external thermal radiation.

[0004] Detector readout noise is a key performance indicator. Designing low-noise readout circuits requires reducing the electronics' readout noise and routing the signals from a large number of detectors out of the package. These challenges are two key considerations.

[0005] In order to reduce the readout noise of the electronics, it is necessary to reduce the lead length between the detector and the electronic readout system as much as possible. Due to the load effect of long wires, especially inductive loads, and impedance discontinuity, signal distortion and signal crosstalk will occur, thereby increasing noise. Therefore, the present invention proposes another solution, which places the preamplifier circuit of the readout electronics system inside the cavity, first pre-amplifies the readout signal, limits the bandwidth, and then leads it out through a vacuum penetrating connector. Since the PCB traces have a good shielding layer, their load effect is small and the impedance is continuous. The signal is amplified before being led out, which can greatly improve the signal-to-noise ratio of the system, but it is necessary to consider the radiation and heat dissipation problems of the PCB at the same time.

[0006] Typical PCB materials have an emissivity above 0.9 and possess a high inherent thermal power, making them the largest radiative heat source within the cavity. Therefore, the radiation issues caused by the PCB cannot be ignored. Furthermore, heat dissipation in electronics is particularly important. For high-power electronic systems, the steady-state temperature under full load can reach hundreds of degrees Celsius. In the preamplifier circuit, higher temperatures introduce significant thermal noise. Furthermore, large temperature fluctuations in the PCB can also affect the stability of the detector's temperature control. Therefore, heat dissipation from high-power PCBs cannot rely solely on PCB thermal radiation; a heat conduction link must be designed to ensure that the PCB's steady-state temperature, both under full load and no-load conditions, is roughly consistent with room temperature.

[0007] The technical problems to be solved by the present invention are the cooling scheme and radiation shielding related to the thermal control of the detector, and the built-in preamplifier circuit scheme and electronic signal penetration related to the low-noise readout of the detector. Summary of the Invention

[0008] In order to solve the above technical problems, the present invention provides a detector vacuum packaging device for low-noise readout.

[0009] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0010] A detector vacuum packaging device for low-noise readout, comprising:

[0011] The encapsulation shell is hollow inside and a glass sealing window is sealed and embedded on the shell of the encapsulation shell;

[0012] The detector is fixed in the packaging shell and arranged opposite to the glass sealing window;

[0013] A radiation isolation mechanism is provided between the detector and the preamplifier circuit mechanism;

[0014] The cooling mechanism includes a refrigerator cold head extending through the package shell and into the package shell, a cold head substrate fixedly mounted on the refrigerator cold head, at least one detector cold chain thermally connecting the cold head substrate and the detector, a heater fixedly mounted on one end of the detector cold chain near the detector, and at least one temperature sensor located in the package shell; the temperature sensor is connected to the heater signal;

[0015] The preamplifier circuit mechanism includes a preamplifier circuit board fixedly mounted in the package shell and connected to the detector signal, a circuit board heat conduction frame fixedly mounted on the preamplifier circuit board, a cold source cold chain heat conduction connecting the circuit board heat conduction frame to the cooling mechanism, and a shell cold chain heat conduction connecting the circuit board heat conduction frame to the package shell;

[0016] The vacuum penetrating piece comprises a vacuum penetrating piece body embedded in and sealed with the packaging shell, and a metal needle penetrating the vacuum penetrating piece body; the front-end circuit board is signal-connected to one end of the metal needle located in the packaging shell.

[0017] Furthermore, the packaging shell includes an upper shell and a bottom flange, and the upper shell is sealed to the bottom flange; the glass sealing window is sealed and embedded in the top surface of the upper shell.

[0018] Furthermore, it includes a supporting mechanism; the supporting mechanism includes a detector substrate, a detector fixing hole opened on the detector substrate, and a substrate bracket; one end of the substrate bracket is fixedly connected to the detector substrate, and the other end is fixedly connected to the packaging shell;

[0019] The detector includes a detector housing, a detector imaging surface fixed on the detector housing and arranged opposite to the glass sealing window, and a detector fixing leg fixed on the bottom of the detector housing; the detector fixing leg is fixedly installed in the detector fixing hole.

[0020] Furthermore, the detector includes a detector housing, and a detector imaging surface fixed on the detector housing and arranged opposite to the glass sealing window;

[0021] The radiation isolation mechanism includes an annular cold screen arranged around the outside of the detector, a circular cold screen located at the bottom of the detector, and a circular light shielding plate; the circumferential edge of the light shielding plate is fixedly connected to the upper end face of the annular cold screen, and the light shielding plate is provided with an opening corresponding to the shape of the detector housing, and the detector is placed in the opening with the imaging surface of the detector protruding upward from the opening.

[0022] Compared with the prior art, the beneficial technical effects of the present invention are:

[0023] The present invention adopts the method of cold chain end thermal compensation to achieve high-precision temperature control of the detector, and adopts a cold screen to isolate thermal radiation. It adopts a built-in preamplifier circuit solution, and the detector output pin is directly input into the PCB. The electronic signal is then led out through a vacuum penetrating piece to achieve low-noise readout.

[0024] Specifically, the present invention has the following advantages:

[0025] 1. Ensure vacuum leak rate and use ion pump to achieve 10 -5 Pa vibration-free vacuum maintenance;

[0026] 2. Minimize readout noise;

[0027] 3. Minimize radiation heat leakage and convection heat exchange;

[0028] 4. Adapt to wide refrigeration temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of a packaging shell in an embodiment of the present invention;

[0031] Figure 3 is a schematic diagram of a typical detector;

[0032] Figure 4 Schematic diagram of a support mechanism in an embodiment of the present invention;

[0033] Figure 5 Schematic diagram of a cooling mechanism in an embodiment of the present invention;

[0034] Figure 6 Schematic diagram of a radiation isolation mechanism in an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of the preamplifier circuit structure in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the detector vacuum packaging device of the present invention includes a packaging shell 1, a detector 2, a support mechanism 3, a radiation shielding mechanism 4, a cooling mechanism 5, and a preamplifier circuit mechanism 6. The detector 2 is mounted in the packaging shell 1 via the support mechanism 3. The cooling mechanism 5 mounted on the support mechanism 3 cools the detector 2 via a refrigerator cold head 505. The radiation shielding mechanism 4 is mounted around the detector 2 to shield radiated heat, improve cooling efficiency, and isolate heat exchange between the detector 2 and the preamplifier circuit board 601. The preamplifier circuit board 601 in the preamplifier circuit mechanism 6 is mounted at the bottom of the cavity of the packaging shell 1 to preamplify the detector 2 signal and improve the signal-to-noise ratio. At the same time, the heat dissipation structure of the preamplifier circuit mechanism conducts heat generated by the circuit away from the cavity of the packaging shell 1 to ensure the operating temperature of the preamplifier circuit board.

[0038] like Figure 2As shown, the package shell 1 includes an upper shell 102, a glass sealing window 101, and a bottom flange 104, and the interior of the package shell 1 is a sealed cavity. The detector 2 receives the light signal through the glass sealing window 101, and the glass sealing window 101 is bonded to the upper shell 102 by epoxy resin. The upper shell 102 is fixed by a knife-edge sealing groove 105 and the bottom flange 104. The bottom flange 104 is provided with a vacuum penetration piece 103 for signal transmission, a support mechanism fixing hole, a refrigerator cold head interface 106, a vacuum exhaust interface 107, and an ion pump interface 108. The refrigerator cold head extends into the package shell 1 through the refrigerator cold head interface, the vacuum exhaust interface 107 is connected to the vacuum source outside the package shell 1, and the ion pump interface 108 is connected to the ion pump outside the package shell 1.

[0039] like Figure 3 As shown, the detector 2 includes a detector imaging surface 201 , a detector cable 202 , a detector fixing base 203 , a detector fixing leg 204 , and a cable plug 205 .

[0040] like Figure 4 As shown, the support mechanism 3 includes a detector substrate 301 and a substrate bracket 303. The detector 2 is mounted on the detector substrate 301 via the detector fixing legs 204 and the detector fixing holes 302 on the detector substrate 301. The detector substrate 301 is fixed to the bottom flange 104 of the package housing 1 via the substrate bracket 303 and the support mechanism fixing holes.

[0041] like Figure 5As shown, the cooling mechanism 5 includes a temperature sensor 501, a heater 502, a detector cold chain 504, a cold head substrate 503, and a refrigerator cold head 505. The cold head substrate 503 is fixed to the refrigerator cold head 505. One end of the detector cold chain 504 is fixed to the cold head substrate 503, and the other end is fixed to the detector substrate 301 and is equipped with a heater 502. The heater 502 controls the temperature of the detector substrate 301. The temperature sensor 501 is mounted on the detector substrate 301, and the detector 2 is mounted on the detector substrate 301 via the detector fixing legs 204. In addition, the detector 2 also has a temperature sensor 501. The refrigerator cold head is used as the cold source. A cold source substrate made of oxygen-free copper is fixed to the refrigerator cold head 505. The cold source substrate and the detector substrate 301 are connected by the detector cold chain 504, thereby cooling the detector substrate 301. In this embodiment, there are four detector cold chains 504. A heater 502 is placed at the end of the detector cold chain 504 near the detector substrate 301 for thermal compensation. Using temperature sensors 501 on the detector substrate 301 and 501 in detector 2, a temperature control algorithm is employed to adjust the compensation power of the corresponding detector cold chain 504. This precisely adjusts the cooling power of each detector cold chain 504, thereby achieving high-precision cooling for the entire detector 2. The detector cold chain 504 utilizes oxygen-free copper braid, and the temperature control algorithm can employ PID control or the more commonly used artificial intelligence control algorithm.

[0042] like Figure 6 As shown, to reduce cooling loss and the impact of heat generated by the front-end circuit board 601 on the detector 2, a cold shield structure is designed to shield the detector 2 from radiation, preventing direct heat exchange between the detector 2 and the outside world. The radiation isolation mechanism includes a light shield 401, an annular cold shield 402, and a circular cold shield 403. An annular cold shield 402 is placed around the detector 2 to shield radiation from the upper housing 102. A circular cold shield 403 is placed at the bottom of the detector 2 to shield radiation from the front-end circuit board 601 and the bottom flange 104. The annular cold shields 402 and 403 require a very high finish, with an emissivity reduced to below 0.1. The shielding of the annular cold shields 402 and 403 reflects nearly all radiation, thereby shielding radiation and reducing the impact of external radiation on temperature control stability. Furthermore, it reduces cooling power consumption and shortens cooling time.

[0043] like Figure 7As shown, to reduce the readout noise of detector 2 and improve the signal-to-noise ratio (SNR), the preamplifier circuit is placed inside the package housing 1. The preamplifier circuit structure 6 includes a preamplifier circuit board 601, a circuit board heat-conducting frame 602, a housing cold chain 603, and a cold source cold chain 604. The cable plug 205 at the end of the detector cable 202 plugs into the connector on the preamplifier circuit board 601. The output signal undergoes AC coupling, operational amplification, and is then output through a vacuum penetrating element 103. The output signal and clock impedance are continuous, and the intact ground layer serves as shielding, greatly improving signal integrity and reducing crosstalk.

[0044] For the heat dissipation of the front-end circuit board 601 when it is working, a "cold source-shell" dual cold chain solution is adopted. The heat conduction frame on the front-end circuit board 601 is connected to the cold source substrate through a slender cold source cold chain 604. At the same time, a thick and short shell cold chain 603 is used to connect the circuit board heat conduction frame 602 and the bottom flange 104. When the front-end circuit board 601 is not working, the cold source cold chain 604 and the shell cold chain 603 form a thermal resistance series structure; when the front-end circuit board is working, the cold source cold chain 604 and the shell cold chain 603 form a thermal resistance parallel structure. By adjusting the thermal resistance ratio of the two cold chains, it can be achieved that the temperature of the electronic system is around room temperature when the front-end circuit board 601 is in the working state and the non-working state, and the cooling amount required at the cold source is equivalent.

[0045] In the present invention, "thermal conductive connection" means that heat can be conducted between two connected objects.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0047] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A detector vacuum packaging device for low-noise readout, characterized in that: include: The encapsulation shell is hollow inside and a glass sealing window is sealed and embedded on the shell of the encapsulation shell; The detector is fixed in the packaging shell and arranged opposite to the glass sealing window; A radiation isolation mechanism is provided between the detector and the preamplifier circuit mechanism; The cooling mechanism includes a refrigerator cold head extending through the package shell and into the package shell, a cold head substrate fixedly mounted on the refrigerator cold head, at least one detector cold chain thermally connecting the cold head substrate and the detector, a heater fixedly mounted on one end of the detector cold chain near the detector, and at least one temperature sensor located in the package shell; the temperature sensor is connected to the heater signal; The preamplifier circuit mechanism includes a preamplifier circuit board fixedly mounted in the package shell and connected to the detector signal, a circuit board heat conduction frame fixedly mounted on the preamplifier circuit board, a cold source cold chain heat conduction connecting the circuit board heat conduction frame to the cooling mechanism, and a shell cold chain heat conduction connecting the circuit board heat conduction frame to the package shell; The vacuum penetrating piece comprises a vacuum penetrating piece body embedded in and sealed with the packaging shell, and a metal needle penetrating the vacuum penetrating piece body; the front-end circuit board is signal-connected to one end of the metal needle located in the packaging shell.

2. The detector vacuum packaging device for low-noise readout according to claim 1, characterized in that: The packaging shell comprises an upper shell and a bottom flange, wherein the upper shell is sealed and connected to the bottom flange; the glass sealing window is sealed and embedded in the top surface of the upper shell.

3. The detector vacuum packaging device for low-noise readout according to claim 1, characterized in that: The supporting mechanism includes a detector substrate, a detector fixing hole provided on the detector substrate, and a substrate bracket; one end of the substrate bracket is fixedly connected to the detector substrate, and the other end is fixedly connected to the packaging shell; The detector includes a detector housing, a detector imaging surface fixed on the detector housing and arranged opposite to the glass sealing window, and a detector fixing leg fixed on the bottom of the detector housing; the detector fixing leg is fixedly installed in the detector fixing hole.

4. The detector vacuum packaging device for low-noise readout according to claim 1, characterized in that: The detector comprises a detector housing, and a detector imaging surface fixed on the detector housing and arranged opposite to the glass sealing window; The radiation isolation mechanism includes an annular cold screen arranged around the outside of the detector, a circular cold screen located at the bottom of the detector, and a circular light shielding plate; the circumferential edge of the light shielding plate is fixedly connected to the upper end face of the annular cold screen, and the light shielding plate is provided with an opening corresponding to the shape of the detector housing, and the detector is placed in the opening with the imaging surface of the detector protruding upward from the opening.

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