Dark substance detection device and method based on density and curvature equivalent relation principle

Abstract

The invention relates to a dark substance detection device and method based on a density and curvature equivalent relation principle, the device comprises a liquid storage tank, the upper port and the lower port of the liquid storage tank are sealed and covered with an upper cover and a lower cover, optical fibers are arranged, and the outer ends of the optical fibers are connected with the transmitting end of a laser power supply-signal receiving integrated host; the lower end of the low-temperature optical fiber beam splitter is fixedly connected with the suspension device; the suspension device is located in the geometric center of the fiducal area, the laser interferometers are fixed to the three vertexes, the emitting end of the low-temperature optical fiber beam splitter is divided into three branch light-guide fibers, and the branch light-guide fibers are connected with riffles in the laser interferometers. Based on the density-curvature equivalent relation, the method is suitable for improving the low-energy signal recognition rate and optimizing the signal-to-noise ratio of the liquid xenon dark matter detector, performance upgrading of the detector and localization replacement of core parts are achieved, and meanwhile the compatibility, safety and engineering economy of the improved detector are guaranteed.

Description

Technical Field

[0001] This application relates to the field of dark matter detection technology, and more particularly to a dark matter detection device and method based on the principle of the equivalence between density and curvature. Background Technology

[0002] Dark matter accounts for 85% of the total matter in the universe, and its detection is a cutting-edge topic in astrophysics and particle physics. Liquid xenon detectors detect dark matter by capturing the scintillation signal (S1, generated by the de-excitation light of xenon atoms excited by the collision) and the ionization signal (S2, generated by the drift of free electrons generated by the collision in an electric field and the secondary ionization light). The XENONnT detector, as the mainstream international liquid xenon dark matter detection device, has a core structure of a double-layer liquid xenon target area (the outer veto region is used to shield external radiation, and the inner fiducial region is the core detection area). Thirty XP2020Q photomultiplier tubes (PMTs) are arranged at the top and bottom of the fiducial region to collect the S1 and S2 signals.

[0003] The main technical limitations of existing XENONnT detectors are as follows: 1. Low recognition rate of low-energy signals: Data released by the XENONnT collaboration in 2023 showed that its recognition rate of low-energy dark matter signals in the 1-5keV energy range was only <5%. Planck's research in 2024 indicated that low-energy dark matter with energies <10keV may account for more than 60% of the total amount of dark matter in the universe. Current detection capabilities cannot meet the research needs of low-energy dark matter. 2. Poor signal-to-noise ratio: The current detector's signal-to-noise ratio is only 0.8, and the signal peaks are affected by cosmic ray muons and material radioactivity (such as...). 238 U、 232 The overlap of background noise peaks such as Th decay particles reaches 65%. The traditional "signal intensity threshold screening" method cannot effectively distinguish between low-energy dark matter signals and noise because it does not address the physical differences between dark matter and noise. 3. Insufficient cost-effectiveness and localization of upgrade solutions: International solutions such as the LUX-ZEPLIN detector increase signal strength by increasing the liquid xenon volume, with a retrofit cost exceeding $300 million and a cycle of 21 months, and core components rely on European and American suppliers; domestic solutions such as the PandaX-4T detector improve the signal-to-noise ratio to 1.8 by optimizing the PMT array gain, but the retrofit cost is 1.8 million yuan and the cycle is 14 months, with a localization rate of less than 30% for core components and poor supply chain stability. 4. High sealing risk: Traditional multi-interface power supply / signal transmission solutions (more than 3 container through-ports) have leakage rates that are difficult to meet long-term operation requirements (≤10).-11 (Pa·m³ / s), indicating a high risk of liquid xenon leakage.

[0004] Therefore, it is necessary to design a dark matter detection device and method based on the principle of density and curvature equivalence that is significantly superior to existing solutions in terms of signal-to-noise ratio, low-energy recognition rate, cost, cycle time, localization rate, and sealing performance. Summary of the Invention

[0005] The purpose of this application is to propose a dark matter detection device based on the principle of density and curvature equivalence, which uses single-interface optical fiber transmission and has density-curvature dual signal verification; based on this purpose, another purpose of this application is to propose a dark matter detection method based on the principle of density and curvature equivalence.

[0006] This application is implemented as follows: A dark matter detection device based on the principle of density and curvature equivalence includes a liquid xenon storage tank, a liquid xenon shielding layer is provided in the outer area of ​​the storage tank, and the upper and lower ports of the storage tank are sealed with an upper cover and a lower cover. Several photomultiplier tubes are inserted into the upper cover and the lower cover, and the incident end of the photomultiplier tube is located inside the storage tank. The feature is that: an optical fiber sealing flange is provided in the center of the upper cover, and an optical fiber passes through the center of the optical fiber sealing flange into the storage tank. The outer end of the optical fiber is connected to the transmitting end of a laser power supply-signal receiving integrated host located outside the storage tank, and the inner end of the optical fiber is connected to the injection end of a low-temperature optical fiber beam splitter. The lower end of the low-temperature optical fiber beam splitter is fixedly connected to a suspension device. The suspension device is located at the geometric center of the fiducial region and includes a regular tetrahedron composed of three transverse connecting rods and three fused silica fibers. The base of the regular tetrahedron is composed of three transverse connecting rods arranged horizontally in an equilateral triangle. A laser interferometer is fixed at each of the three vertices of the equilateral triangle, and the emitting end of the laser interferometer is aligned with the center of the regular tetrahedron. The low-temperature fiber optic beam splitter branches into three branch optical fibers at its output end, and these branch optical fibers are connected to the splitter inside the laser interferometer.

[0007] An insulating base with an equilateral triangular distribution is provided in the middle of the bottom surface of the upper cover. A suspension rod of equal length is suspended from the bottom surface of the insulating base, and the lower end of the suspension rod is fixedly connected to the upper end of the outer wall of the laser interferometer.

[0008] Three branch optical fibers are laid out along the surface of fused silica fiber. The fused silica fiber is fixed every 5 cm with low-temperature polytetrafluoroethylene cable ties. The ends of the branch optical fibers are connected to the splitter in the laser interferometer through gold-plated ST connectors.

[0009] The insulating base is 40cm from the top photomultiplier tube, and the suspension device is 75cm from the bottom photomultiplier tube.

[0010] The center-to-center distance between adjacent laser interferometers is 20cm. The laser emitting ends of the laser interferometers are all aligned with the central collision area of ​​the fiducial region. The horizontal distance between the central collision area of ​​the fiducial region and each laser interferometer is 10cm.

[0011] A dark matter detection method based on the principle of density-curvature equivalence is characterized by the following steps: Step 1, Signal Preprocessing: The two types of light signals collected are processed. The first is the initial light signal (S1) generated by dark matter particles colliding with the liquid xenon nucleus. The second is the secondary ionization signal (S2) generated by charged particles such as cosmic rays and radioactive particles colliding with the liquid xenon and causing electrons to move in the electric field and ionize the liquid xenon again. A 10ms window moving average filter is used to suppress high-frequency noise above 100Hz. The signal-to-noise ratio can be improved by 3 times after filtering. Step two: After completing signal preprocessing, the following event identification logic is used to determine whether the acquired signal is a valid event: (1) Determination of proportional coefficient deviation: Calculate the ratio k' = ρ / R of ρ after filtering, and compare it with the standard proportional coefficient k = 1.2 × 10 23 m -5 ·kg -1 In comparison, the deviation is defined as δ = |(k'-k) / k| × 100%, and δ ≤ 10% is considered a preliminary valid event; (2) Waveform similarity verification: Dynamic time warping is used to compare the signal to be verified with the template signal in the XENONnT 2023 dark matter simulation waveform library, and the similarity S (S=1-total path distance / maximum path distance) is calculated. S>90% is a secondary valid event; (3) Synchronization determination: Verify that the time difference between the ρ / R change and the S1 / S2 signal is <10 using the DAQ acquisition card timestamp. - 9 If s is satisfied, it is determined to be a dark matter event; otherwise, it is a noise event.

[0012] By implementing the above technical solutions, this application, based on the density-curvature equivalence relationship, adopts all domestically produced core components, which is suitable for improving the low-energy signal recognition rate and optimizing the signal-to-noise ratio of liquid xenon dark matter detectors. In particular, it addresses the existing problems of XENONnT detectors, such as a low-energy dark matter signal recognition rate of <5% (1-5keV), a signal-to-noise ratio of 0.8, reliance on imported core components, and high sealing risks of multiple interfaces. It achieves detector performance upgrades and domestic substitution of core components, while ensuring the compatibility, safety, and engineering economy of the modified detector.

[0013] The main advantages are as follows: 1. Breakthrough performance improvement: The signal-to-noise ratio has increased from 0.8 to ≥2.5 (+212.5%), and the recognition rate of 1-5keV low-energy dark matter signals has increased from <5% to ≥65% (+1200%), effectively filling the technological gap in low-energy dark matter detection and providing key detection equipment support for Planck's 2024 research on "low-energy dark matter accounting for more than 60%". 2. Sealing and Safety Guarantee: Utilizing top-mounted single-interface fiber optic transmission reduces sealing risk by 67%, achieving a leakage rate that meets GB / T 37248-2018 Class I standard (≤1×10⁻⁶). -11 (Pa·m³ / s) completely eliminates the hidden danger of liquid xenon leakage; the total radioactivity of all parts is <0.3Bq / kg, and the purity of liquid xenon is maintained at ≥99.9999%, meeting the requirements for long-term (≥5 years) stable operation of the detector; 3. Advantages of localization and economy: 100% of the core components are domestically produced, eliminating dependence on European and American supply chains. The transformation cost is only 480,000 yuan (73% lower than the domestic PandaX-4T solution and 99.9% lower than the international LUX-ZEPLIN solution), and the transformation cycle is 4 months (71% shorter than the PandaX-4T solution), which greatly reduces the cost and cycle of upgrading scientific research equipment. 4. High compatibility and scalability: Without altering the original main structure of the detector (veto region, cooling system, shielding layer), the total power consumption of the new equipment is less than 3W, and it can be seamlessly integrated with the existing data system; the solution can be directly adapted to similar liquid xenon detectors such as LUX-ZEPLIN and PandaX-4T, and can also be extended to fields such as inertial confinement fusion experiments (plasma density monitoring) and quantum precision measurement (spacetime curvature measurement), with broad application prospects. Attached Figure Description

[0014] The specific structure of this application is given by the following figures and embodiments: Figure 1 This is a schematic diagram of the device structure of this application; Figure 2 This is a schematic diagram of the connection between the suspension support device and the laser interferometer and optical fiber; Figure 3 This is a schematic diagram of the optical and circuit connections of this application.

[0015] Legend: 1. Optical fiber, 2. Photomultiplier tube, 3. Fiber optic sealing flange, 4. Top cover, 5. Suspension device, 51. Insulating base, 52. Suspension rod, 53. Low temperature fiber optic beam splitter, 54. Laser interferometer, 55. Lateral connecting rod, 56. Fused silica fiber, 57. Cable tie, 58. Branched optical fiber, 6. Bottom cover, 7. Liquid storage tank, 8. Connecting rod. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0017] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0018] Example: Figure 1-3 As shown, the dark matter detection device based on the principle of density and curvature equivalence includes a liquid xenon storage tank 7, a liquid xenon shielding layer around the storage tank 7, and upper and lower sealed caps 4 and 6 at the upper and lower ends of the storage tank 7. Several photomultiplier tubes 2 are inserted into the upper and lower caps 4 and 6, respectively. The incident ends of the photomultiplier tubes 2 are located inside the storage tank 7. An optical fiber sealing flange 3 is located at the center of the upper cap 4. An optical fiber 1 passes through the center of the optical fiber sealing flange 3 into the storage tank 7. The outer end of the optical fiber 1 is connected to the transmitting end of a laser power supply-signal receiving integrated host located outside the storage tank 7, and the inner end of the optical fiber 1 is connected to the injection end of a low-temperature optical fiber beam splitter 53. The lower end of the low-temperature optical fiber beam splitter 53 is fixedly connected to a suspension device 5. The photomultiplier tubes 2 are connected to the DAQ acquisition card circuit of the laser power supply-signal receiving integrated host. The suspension device 5 includes a regular tetrahedron composed of three transverse connecting rods 55 and three fused silica fibers 56. The bottom surface of the regular tetrahedron is composed of three transverse connecting rods 55 arranged horizontally in an equilateral triangle. A laser interferometer 54 is fixed at each of the three vertices of the equilateral triangle, and the emitting end of the laser interferometer 54 is aligned with the center of the regular tetrahedron. Three branch optical fibers 58 are split from the output end of the low-temperature fiber beam splitter 53, and the branch optical fibers 58 are connected to the splitter in the laser interferometer 54.

[0019] Furthermore, an insulating base 51 arranged in an equilateral triangle is provided in the center of the bottom surface of the upper cover 4. A suspension rod 52 of equal length hangs from the bottom surface of the insulating base 51, and the lower end of the suspension rod 52 is fixedly connected to the upper end of the outer wall of the laser interferometer 54. The suspension rod 52 keeps the bottom surface of the regular tetrahedron horizontal, ensuring that the three laser interferometers 54 are located on the same plane. With the combined connection of the suspension device 5 and the suspension rod 52, the laser interferometers 54 can be stably positioned in the liquid xenon, ensuring that their emitting ends are stably aligned with the center of the regular tetrahedron.

[0020] Furthermore, three branch optical fibers 58 are respectively laid along the surface of the fused silica fiber 56. A low-temperature polytetrafluoroethylene cable tie 57 (1mm wide, 0.1mm thick) is used to fix the fused silica fiber 56 every 5cm. The ends of the branch optical fibers 58 are connected to the splitter inside the laser interferometer 54 via gold-plated ST connectors. The gold-plated ST connector is existing technology; ST stands for Straight Tip, a common circular fiber optic connector with a bayonet structure. The gold-plated ST connector is simply an ST fiber optic connector with a gold-plated surface. Gold has good conductivity and oxidation resistance, making the connection more stable and reducing signal loss. Specifically, the manufacturer is Shengnuo Precision Industry Co., Ltd., and the customized model is ST-M20 series, with a contact resistance of <10mΩ for 177K.

[0021] The aforementioned photomultiplier tube 2, laser power supply-signal receiving integrated host, low-temperature fiber optic beam splitter 53, laser interferometer 54, and other components are all existing technologies. Specific models are shown in the table below. .

[0022] This application is based on the structural improvement of the fiducial region (suspension) of the XENONnT detector, and does not involve the outer veto region (the rejection region, the forbidden region, the region that excludes most of the interference signals), the liquid xenon shielding layer, or the improvement of the top / bottom PMT (photomultiplier tube) array (the original 30 pairs of XP2020Q type) and the external cooling system (500W power).

[0023] Furthermore, a connecting rod 8 is fixedly connected to the lower end face of the upper cover 4 and the upper end face of the lower cover 6 in the area outside the liquid storage tank 7, in order to enhance the stability of the sealing connection between the upper cover 4, the lower cover 6 and the liquid storage tank 7.

[0024] The insulating base 51 is 40cm from the top PMT (photomultiplier tube). The suspension device 5 is located at the geometric center of the fiducial (reference, standard position) region and 75cm from the bottom PMT (photomultiplier tube). The center-to-center distance between adjacent laser interferometers 54 is 20cm. The laser emitting ends of all laser interferometers 54 are aligned with the central collision area of ​​the fiducial region. The horizontal distance between the central collision area of ​​the fiducial region and each laser interferometer 54 is 10cm.

[0025] The storage tank 7 is filled with liquid xenon, and the liquid xenon level is higher than the suspension device 5. The laser power supply and signal receiving integrated host (integrated 5W 1064nm continuous wave laser, model LD-1064-5W, with dual functions of laser emission and optical signal reception) outside the storage tank 7 emits laser light, which is transmitted to the storage tank 7 through the main optical fiber 1 (transmission efficiency 95%). The laser light first enters the 1:3 cryogenic fiber beam splitter 53 (splitting ratio 1:1:1, insertion loss <0.5dB) in the storage tank 7, and is split into three paths. After being split into three paths, they are connected to the respective splitters (1:2 beam splitters) of the three laser interferometers 54 through three branch optical fibers 58. The splitter of the laser interferometer splits a branch optical fiber 58 into two optical fibers: one connects to the built-in miniature photoelectric conversion module (model GDC-2024) of the laser interferometer 54, which converts laser energy into DC power to power the laser interferometer 54 (single unit power consumption ≤1W, total power consumption of 3 units ≤3W); the other connects directly to the built-in miniature signal modem (model GTM-2024) of the laser interferometer 54.

[0026] The three laser interferometers 54 inside the storage tank 7 first convert the collected curvature signal into optical path difference (optical signal) and send it to their own built-in miniature signal modem. The modem encodes the optical signal into a 1MHz optical pulse signal and transmits it in reverse along the original optical fiber to the splitter of the laser interferometer 54, and then to the low-temperature optical fiber beam splitter 53. The signal is then transmitted back to the laser power supply-signal receiving integrated host via optical fiber 1. The host receives the returned optical signal through its built-in signal receiving module, converts the received optical signal into a 0-5V electrical signal, and then transmits it to the ART2018 DAQ acquisition card (installed in the expansion slot of the industrial control computer of the integrated host). After the DAQ acquisition card acquires and quantizes the electrical signal, it transmits the digital signal to the server host to complete data storage and analysis.

[0027] Only when dark matter particles (uncharged) collide with the liquid xenon nucleus do the resulting light and curvature signals are almost synchronized (time error < 100 nanoseconds). The light signal is acquired by photomultiplier tube 2, while the curvature signal is acquired by laser interferometer 54. After both are converted into electrical signals, they are transmitted to the DAQ acquisition card and timestamped. When the timestamps are close (< 100 nanoseconds) or the same, it can be determined that dark matter particles have been detected.

[0028] The dark matter detection method based on the principle of density-curvature equivalence includes the following steps: Step 1, Signal Preprocessing: The two types of light signals collected are processed. The first is the initial light signal (S1) generated by dark matter particles colliding with the liquid xenon nucleus. The second is the secondary ionization signal (S2) generated by charged particles such as cosmic rays and radioactive particles colliding with the liquid xenon and causing electrons to move in the electric field and ionize the liquid xenon again. A 10ms window moving average filter is used to suppress high-frequency noise above 100Hz. The signal-to-noise ratio can be improved by 3 times after filtering. Step two: After completing signal preprocessing, the following event identification logic is used to determine whether the acquired signal is a valid event: (1) Determination of proportional coefficient deviation: Calculate the ratio k' = ρ / R of ρ after filtering, and compare it with the standard proportional coefficient k = 1.2 × 10 23 m -5 ·kg -1 In comparison, the deviation is defined as δ = |(k'-k) / k| × 100%, and δ ≤ 10% is considered a preliminary valid event; (2) Waveform similarity verification: Dynamic time warping (DTW: Dynamic Time Warping Algorithm. It can adjust and align time series of different lengths. For example, signals with different rhythms can be easily compared and analyzed after processing with it. In our patent, if it involves signal sequence processing algorithms, the signal to be verified is compared with the template signal in the XENONnT 2023 Dark Matter Simulation Waveform Library. The similarity S (S=1-total path distance / maximum path distance) is calculated. If S>90%, it is a secondary valid event. (3) Synchronization determination: Verify that the time difference between the ρ / R change and the S1 / S2 signal is <10 using the DAQ acquisition card timestamp. - 9 If s is satisfied, it is determined to be a dark matter event; otherwise, it is a noise event (such as the asynchronous signal of muons or the out-of-position signal of alpha particles).

[0029] The local density change (ρ) caused by the collision of dark matter particles with liquid xenon nuclei satisfies the equivalence relationship with the spacetime curvature change (R): R = k×ρ, where k = 1.2×10 23 m -5 ·kg -1 The relative error is verified by the Laser Interferometer Gravitational-Wave Observatory (LIGO) on November 23, 2023, during the binary black hole merger event (GW231123).

[0030] External system connection and integration in this application: (1) Hardware connection: After passing through the liquid storage tank 7, the optical fiber 1 is connected to the optical fiber interface of the laser power supply-signal receiving integrated host; the signal output end (BNC interface) of the laser power supply-signal receiving integrated host is connected to the analog input three channels of the ART2018 DAQ acquisition card through a double shielded cable, corresponding to three laser interferometers 54; the DAQ acquisition card is also connected to the signal output end of the detector's original PMT array through a cable, and connected to the existing XENONnT data server (compatible with ROOT data framework). (2) System debugging: Start the integrated laser power supply and signal receiver host, adjust the output power of the laser source to 5W, monitor the power supply voltage of the three laser interferometers 54 (3.3V±0.05V) to ensure stable power supply; use a standard optical path difference calibrator (accuracy 10⁻¹³m) to test the curvature measurement accuracy of the laser interferometer 54 to ensure that the optical path difference measurement error at 177K is <10-12m; trigger the S1 analog signal of the PMT (use an LED source to simulate 178nm photons), synchronously collect the S1 signal and curvature signal, and calibrate the two signals through the DAQ acquisition card timestamp to make the time synchronization error of the two signals <100ns.

[0031] Performance testing and acceptance in this application: (1) Low-energy signal recognition rate test: using 137 A Csγ source (energy 662 keV) attenuates the radiation energy to 1-5 keV through a lead shield (5 cm thick) and a copper attenuator (1 mm thick) to irradiate the center of the fiducial region; 10 samples are continuously collected. 5 A group of signals, statistically satisfying "δ≤10%+S>90%+Time difference<10" -9 The number of events with the 's' symbol is used to calculate the low-energy recognition rate, which must be ≥65%. (2) Signal-to-noise ratio test: Acquire the waveform of a 1keV analog signal, calculate the ratio of peak-to-peak value of the signal (Vpp) to root mean square noise (Vrms), which must be ≥2.5; 3. Long-term stability test: Continuous operation for 30 days, with daily recording of interferometer power supply voltage, liquid xenon purity (LIBS detection), and leakage rate (helium mass spectrometry leak detection); after 30 days, the following parameters should be observed: power supply voltage fluctuation ≤ ±0.05V, liquid xenon purity ≥ 99.9999%, and leakage rate ≤ 1×10⁻⁶. -11 Pa·m 3 / s indicates stable operation.

[0032] Complete derivation of the density-curvature equivalence relationship: (1) Spatiotemporal geometric correlation quantities ; (2) Collision system related quantities ; (3) Physical constants ; (4) Experimental measurement of relevant quantities

[0033] (5) Quantum correction correlation quantity ; (6) Special radius quantities .

[0034] A.1 Fundamental Equations and Core Definitions 1. Expression for spacetime curvature (Ricci scalar) Physical background: The collision between dark matter and liquid xenon nuclei is a local instantaneous process that satisfies the conditions of spherical symmetry, static state, and weak field. Derivation process: (1) Schwarzschild gauge line element: ; in: ; (2) Weak field approximation: correction term It can be approximated as: ; in: ; (3) Curvature calculation: Christofel symbol key components: ; in: ; (4) Riemann curvature tensor components: ; in: ; (5) Ricci scalar: ; in: ; (6) Conclusion: ; in: .

[0035] 2. Relationship between equivalent mass and density Physical background: Liquid xenon molecules briefly aggregate into spheres in the collision region; Derivation: Volume of the collision region ; in: ; therefore: ; in: .

[0036] 3. Correlation between density and observable signal Physical background: The S1 photon number NS1 is positively correlated with the local density ρ; Relationship: ρ=k ρ ·N S1 in: - ρ: Local density of liquid xenon, unit: kg·m -3 Dimension: M·L -3 - k ρ : Conversion factor from S1 signal to density, unit: kg·m -3 Dimension: M·L -3 - N S1 S1 scintillation signal photon count, unit: dimensionless; K ρ =1.2×10 -3 kg·m -3 (95% confidence interval 1.18×10) -3 ~1.22×10 -3 ) in: - k ρ : Conversion factor from S1 signal to density, unit: kg·m -3 Dimension: M·L -3 .

[0037] A.2 Derivation of core relationships (density-curvature equivalence relationship) 1. Fundamental Relations in Classical Field Theory Derivation: We will get: ; in: ; ; in: ; in: .

[0038] 2. Quantum Correction Physics background: Liquid xenon electrons are fermions, and the Pauli exclusion principle leads to increased density during collisions; Electron number density: ; in: ; Correction factor: ; in: ; Correction relation: ; in: .

[0039] A.3 Experimental Verification Parameter: Dark matter mass ; in: -N S1 S1 scintillation signal photon count, unit: dimensionless; Calculation process: .

[0040] A.4 Strong Field Correction Physical background: When the collision energy is high (> 100 keV), the weak field approximation no longer holds strictly; Higher-order expansion of metric: ; ;

[0041] A.5 Quantum Gravity Correction Physical background: at extremely short distances Quantum gravity effects may lead to quantum fluctuations in spacetime geometry; Fluctuation estimation: ; .

[0042] A.6 Conclusion Through classical field theory derivation, quantum correction, and experimental verification, the density-curvature equivalence relationship in the collision process between dark matter and liquid xenon nuclei is finally expressed as: ; in: - R: Ricci scalar, unit: m -2 Dimension: L -2 - ρ: Local density of liquid xenon, unit: kg·m -3 Dimension: M·L -3 .

[0043] The above technical features constitute the embodiments of this application, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A dark matter detection device based on the principle of density and curvature equivalence, comprising a liquid xenon storage tank, a liquid xenon shielding layer disposed around the tank, an upper cover and a lower cover sealing the upper and lower ports of the tank, and a plurality of photomultiplier tubes inserted into the upper and lower covers, the incident ends of the photomultiplier tubes being located inside the tank, characterized in that: An optical fiber sealing flange is set in the center of the top cover. The optical fiber passes through the center of the optical fiber sealing flange into the liquid storage tank. The outer end of the optical fiber is connected to the transmitter of the integrated laser power supply and signal receiver located outside the liquid storage tank. The inner end of the optical fiber is connected to the injection end of the low temperature optical fiber beam splitter. The lower end of the low temperature optical fiber beam splitter is fixedly connected to the suspension device. The suspension device is located at the geometric center of the fiducial region and includes a regular tetrahedron composed of three transverse connecting rods and three fused silica fibers. The base of the regular tetrahedron is composed of three transverse connecting rods arranged horizontally in an equilateral triangle. A laser interferometer is fixed at each of the three vertices of the equilateral triangle, and the emitting end of the laser interferometer is aligned with the center of the regular tetrahedron. The low-temperature fiber optic beam splitter branches into three branch optical fibers at its output end, and these branch optical fibers are connected to the splitter inside the laser interferometer.

2. The dark matter detection device based on the principle of density and curvature equivalence as described in claim 1, characterized in that: An insulating base with an equilateral triangular distribution is provided in the middle of the bottom surface of the upper cover. A suspension rod of equal length is suspended from the bottom surface of the insulating base, and the lower end of the suspension rod is fixedly connected to the upper end of the outer wall of the laser interferometer.

3. The dark matter detection device based on the principle of density and curvature equivalence as described in claim 1, characterized in that: Three branch optical fibers are laid out along the surface of fused silica fiber. The fused silica fiber is fixed every 5 cm with low-temperature polytetrafluoroethylene cable ties. The ends of the branch optical fibers are connected to the splitter in the laser interferometer through gold-plated ST connectors.

4. The dark matter detection device based on the principle of density and curvature equivalence as described in claim 2, characterized in that: The insulating base is 40cm from the top photomultiplier tube, and the suspension device is 75cm from the bottom photomultiplier tube.

5. The dark matter detection device based on the principle of density and curvature equivalence as described in claim 1, characterized in that: The center-to-center distance between adjacent laser interferometers is 20cm. The laser emitting ends of the laser interferometers are all aligned with the central collision area of ​​the fiducial region. The horizontal distance between the central collision area of ​​the fiducial region and each laser interferometer is 10cm.

6. A dark matter detection method based on the principle of density-curvature equivalence, characterized in that: Includes the following steps, Step 1, Signal Preprocessing: The two types of light signals collected are processed. The first is the initial light signal (S1) generated by dark matter particles colliding with the liquid xenon nucleus. The second is the secondary ionization signal (S2) generated by charged particles such as cosmic rays and radioactive particles colliding with the liquid xenon and causing electrons to move in the electric field and ionize the liquid xenon again. A 10ms window moving average filter is used to suppress high-frequency noise above 100Hz. The signal-to-noise ratio can be improved by 3 times after filtering. Step two: After completing signal preprocessing, the following event identification logic is used to determine whether the acquired signal is a valid event: (1) Determination of proportional coefficient deviation: Calculate the ratio k' = ρ / R of ρ after filtering, and compare it with the standard proportional coefficient k = 1.2 × 10 23 m -5 ·kg -1 In comparison, the deviation is defined as δ = |(k'-k) / k| × 100%, and δ ≤ 10% is considered a preliminary valid event; (2) Waveform similarity verification: Dynamic time warping is used to compare the signal to be verified with the template signal in the XENONnT 2023 dark matter simulation waveform library, and the similarity S (S=1-total path distance / maximum path distance) is calculated. S>90% is a secondary valid event; (3) Synchronization determination: Verify that the time difference between the ρ / R change and the S1 / S2 signal is <10 using the DAQ acquisition card timestamp. -9 If s is satisfied, it is determined to be a dark matter event; otherwise, it is a noise event.

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