Ultrasonic molecular beam low temperature injection system and method based on cluster size feedback control

Abstract

The application provides an ultrasonic molecular beam low-temperature injection system and method based on cluster size feedback control, relates to the technical field of fusion device fuel gas injection, and solves the problems of the prior art, such as difficulty in forming stable clusters. In the system, a gas supply and pressure regulation unit provides gas supply and regulates the pressure of the injection gas, a helium cooling unit provides low-temperature cooling capacity to the injection unit, a temperature control unit regulates the gas temperature of the injection unit, the injection unit generates an ultrasonic molecular beam under the condition of a set pressure and a set temperature and injects the ultrasonic molecular beam into a fusion device, a cluster measurement unit detects the cluster size of the generated ultrasonic molecular beam and outputs a cluster size signal, and an intelligent control processing unit outputs a pressure regulation instruction and a temperature regulation instruction based on the cluster size signal, so that the actual cluster size of the ultrasonic molecular beam approaches a target value. The application realizes controllable generation and injection of cluster ultrasonic molecular beams and achieves the effect of injecting a specific number of cluster ultrasonic molecular beams.

Description

Technical Field

[0001] This invention relates to the field of fuel gas injection technology for fusion devices, and more specifically to a cryogenic ultrasonic molecular beam injection system and method based on cluster size feedback control. Background Technology

[0002] Supersonic molecular beam injection (SMBI) technology, a key method for achieving efficient fuel feeding in magnetic confinement fusion devices, has been widely used in existing experimental facilities due to its high injection efficiency and low gas wall retention characteristics. As fusion devices develop towards larger scales and higher parameters, more stringent requirements are placed on the beam velocity, spatial focusing capability, and fuel deposition efficiency of the injection technology. Studies have shown that the formation of cluster structures in the molecular beam has a significant impact on beam dynamics. Appropriately increasing the number of cluster particles can effectively enhance the directional focusing characteristics of the beam, reduce divergence losses during transmission, and thus significantly improve the fuel feeding efficiency in the plasma boundary region.

[0003] Cluster size regulation mainly depends on the initial thermodynamic state of the gas, with gas source pressure and temperature being the core influencing factors. For example... Figure 1 As shown, the air pressure P1 to air pressure P n As the pressure gradually decreases, this figure reflects the mapping relationship between temperature and cluster size under different gas source pressures. While increasing the gas source pressure helps promote cluster growth, the pressure setting must prioritize ensuring that the total particle flux of a single injection meets the basic experimental requirements, thus severely limiting its adjustment space. In contrast, lowering the initial temperature of the injected gas becomes a more flexible and feasible technical approach to optimize cluster formation conditions. It can effectively improve cluster size and stability while maintaining a stable total injection volume, providing a physical basis for improving feeding efficiency.

[0004] Current engineering solutions for gas cooling mostly employ indirect cooling of nozzles or gas paths using liquid nitrogen; however, this method has significant limitations. The thermodynamic properties of liquid nitrogen dictate a physical lower limit to its cooling capacity, making it difficult to meet the physical requirements for the formation of stable, large-sized clusters of light fuels such as hydrogen and deuterium under cryogenic conditions. Furthermore, these cooling structures are mostly fixed, passive designs, lacking continuity and precision in temperature regulation, and unable to adapt to dynamic changes in experimental conditions. In addition, the systems generally lack in-situ sensing capabilities for cluster characteristic parameters, making it difficult to establish a quantitative correlation between temperature control and cluster formation effects. This results in an open-loop process, where the control effect is highly dependent on operational experience.

[0005] Traditional injection systems typically rely on engineering parameters such as gas pressure and valve pulse width for control, failing to incorporate cluster size—an intrinsic physical quantity determining fueling efficiency—into the control target system. This approach results in a lack of quantifiable and traceable control over the cluster formation process, making it difficult to achieve stable reproduction and precise transfer of process parameters across different experimental conditions or devices. In fusion experiments, injection requirements are frequently adjusted according to discharge targets, and current technologies cannot provide repeatable and predictable cluster size control capabilities, thus limiting the reliability and adaptability of the fuel feeding process.

[0006] In summary, existing ultrasonic molecular beam cryogenic injection technology has shortcomings in terms of temperature control range, adjustment precision, process sensing capability, and control logic, making it difficult to meet the comprehensive requirements of future fusion devices for efficient, controllable, and adaptable fuel injection. There is an urgent need to develop a new technical approach that can achieve precise temperature control over a wide temperature range and directly optimize cluster size, providing a more reliable and intelligent fuel injection solution for fusion experiments. Summary of the Invention

[0007] The purpose of this invention is to address the problems in existing cryogenic ultrasonic molecular beam injection technology, where light element fuel gases are difficult to form stable clusters due to limited cooling capacity, and the cluster size control process relies on empirical settings, lacking repeatability and predictability. This invention proposes a cryogenic ultrasonic molecular beam injection system and method based on cluster size feedback control. Unlike existing technologies that control injection parameters, this invention uses cluster size, which directly affects feeding efficiency, as the control target. This system and solution can be programmed according to user needs, using cluster size as the control target, to automatically adjust pressure and matching gas temperature, achieving controllable generation and injection of clustered ultrasonic molecular beams, and realizing the advantages of injecting a specific number of clustered ultrasonic molecular beams.

[0008] The present invention employs the following technical solutions to achieve its objective: A cryogenic ultrasonic molecular beam injection system based on cluster size feedback control, comprising a gas supply and pressure regulation unit, a helium cooling unit, a temperature control unit, an injection unit, a cluster measurement unit, and an intelligent control and processing unit; The gas supply and pressure regulation unit is in fluid communication with the injection unit and is used to provide gas supply and regulate the pressure of the injected gas. The cold end of the helium cooling unit is thermally coupled to the injection unit to provide cryogenic cooling to the injection unit; The temperature control unit is connected to the injection unit and is used to adjust the gas temperature of the injection unit; The injection unit is configured to generate an ultrasonic molecular beam and inject it into the fusion device under set pressure and temperature conditions. The cluster measurement unit is configured to detect the cluster size of the ultrasonic molecular beam generated by the injection unit and output a cluster size signal; The intelligent control processing unit is connected to the gas supply and pressure regulation unit, the helium cooling unit, the temperature control unit, the injection unit, and the cluster measurement unit. The intelligent control processing unit is configured to receive the cluster size signal and, based on a preset cluster size target value, output a pressure adjustment command to the gas supply and pressure regulation unit and a temperature adjustment command to the temperature control unit, so that the actual cluster size of the ultrasonic molecular beam generated by the injection unit approaches the cluster size target value.

[0009] Specifically, the gas supply and pressure regulation unit includes a high-pressure gas source, a valve assembly, a gas storage tank, an automatic pressure controller, and a safety relief device. The high-pressure gas source is connected to the gas storage tank via a gas pipe. The valve assembly is installed on the gas pipe between the high-pressure gas source and the gas storage tank to initially reduce the pressure of the gas from the high-pressure gas source. The outlet of the gas storage tank is connected to the automatic pressure controller, and the outlet of the automatic pressure controller is in fluid communication with the inlet of the injection unit. The automatic pressure controller is also signal-connected to the intelligent control processing unit to receive pressure regulation commands and maintain the set pressure in real time. The safety relief device is used to release gas from the gas supply and pressure regulation unit under preset safety conditions.

[0010] Specifically, the helium cooling unit includes a helium compressor, a helium pipe, and a cold head; the helium compressor delivers the working medium to the cold head through the helium pipe, and the cold head is attached to the copper seat of the injection unit via a copper adapter to form a thermal coupling path; the cold head adopts a flange-type assembly structure and is fixedly connected to the vacuum chamber of the injection unit, so that the low-temperature cooling capacity is conducted to the injection unit.

[0011] Specifically, the temperature control unit includes a temperature controller, a thermometer, and a heater; the thermometer and the heater are integrated and installed on the copper base surface of the injection unit, and the temperature controller is signal-connected to the intelligent control processing unit; the temperature controller is configured to control the output power of the heater according to the received temperature adjustment command, so that the heat generated by the heater and the cooling capacity provided by the helium cooling unit reach a dynamic balance, and control the gas temperature in the injection unit at a set value.

[0012] Specifically, the injection unit includes a vacuum chamber, a gas supply line, a solenoid valve, a Laval nozzle, and a copper base; the copper base encloses the gas supply line and the solenoid valve, and the Laval nozzle is disposed in the vacuum chamber and fixedly connected to the copper base; the vacuum chamber is provided with an air inlet that communicates with the gas supply and pressure regulation unit; the injection unit also uses a multi-needle vacuum penetrator to achieve signal connection between the device control circuit inside the vacuum chamber and the intelligent control processing unit.

[0013] Specifically, the cluster measurement unit includes a laser, an optical lens group, a synchronizer, and a signal receiving device. The optical lens group guides the probe light emitted by the laser to the Laval nozzle exit region of the injection unit, so that the probe light interacts with the ejected ultrasonic molecular beam to generate scattered light. The signal receiving device collects the scattered light signal and converts it into an electrical signal, which is then output to the intelligent control processing unit. The synchronizer is signal-connected to the intelligent control processing unit and is used to coordinate and control the triggering time of the laser, the opening time of the solenoid valve in the injection unit, and the sampling timing of the signal receiving device.

[0014] Preferably, the intelligent control processing unit has a built-in multi-parameter mapping relationship database of cluster size and temperature; the multi-parameter mapping relationship database is constructed based on different gas types and associated with pressure range and nozzle operating parameters; the intelligent control processing unit is also configured to update and correct the corresponding parameters in the multi-parameter mapping relationship database online based on the cluster size signal fed back by the cluster measurement unit.

[0015] Preferably, the intelligent control processing unit is further configured to, after receiving the cluster size target value set by the user, verify whether it is within the adjustable parameter range of the system, and generate a warning signal if it exceeds the range; during the ultrasonic molecular beam injection process, the intelligent control processing unit dynamically adjusts the pressure adjustment command sent to the gas supply and pressure regulation unit and the temperature regulation command sent to the temperature control unit based on the deviation between the cluster size signal fed back by the cluster measurement unit in real time and the cluster size target value.

[0016] This invention also provides a method for cryogenic injection of ultrasonic molecular beams based on the aforementioned system, the method comprising the following steps: S1, Target value for receiving cluster size; S2. Based on the target value of the cluster size, generate pressure adjustment command and temperature adjustment command; S3. According to the pressure adjustment command, control the gas supply and pressure regulation unit to adjust the pressure of the injected gas; according to the temperature regulation command, control the temperature control unit to adjust the gas temperature of the injected unit. S4. After the pressure and gas temperature reach the set conditions, control the injection unit to generate an ultrasonic molecular beam and inject it into the fusion device; S5. The actual cluster size of the ultrasonic molecular beam is synchronously acquired through the cluster measurement unit, and a cluster size signal is generated. S6. Compare the cluster size signal with the cluster size target value, update the pressure adjustment command and / or the temperature adjustment command according to the comparison result, and return to step S3 to repeat until the injection process ends.

[0017] Preferably, in step S1, gas type information and gas pressure setpoint are received synchronously; in step S2, before generating the pressure adjustment command and the temperature adjustment command, it is verified whether the cluster size target value, the gas type information and the gas pressure setpoint are within the system's preset adjustable parameter range, and if they exceed the range, a warning signal is generated; in step S6, all data related to the gas pressure, gas temperature and actual cluster size corresponding to this injection are associated and stored, and the multi-parameter mapping relationship database of cluster size and temperature built into the intelligent control processing unit is updated and corrected online.

[0018] In summary, due to the adoption of this technical solution, the beneficial effects of this invention are as follows: This invention enables deep and controllable cooling of light element fuel gases such as hydrogen and deuterium, effectively expanding the thermodynamic applicability of cluster formation and overcoming the inherent limitations of traditional cooling methods in terms of temperature limit and adjustment continuity. It provides a reliable low-temperature environment basis for the formation of stable cluster structures of light element gases.

[0019] This invention establishes cluster size as the core physical quantity for system control, transforming the generation process of ultrasonic molecular beams from empirical control of traditional engineering parameters to precise adjustment based on physical quantities. This enables the cluster size to be settable, predictable, and highly repeatable, significantly improving the stability and cross-condition reproducibility of the injection process under different experimental conditions.

[0020] This invention can continuously optimize the correlation between gas type, pressure and temperature based on feedback signals, enabling the system to have adaptive response capability to changes in experimental conditions, and enhancing the robustness and intelligence of the control strategy in complex operating environments.

[0021] This invention optimizes the transport characteristics and deposition behavior of fuel particles in the boundary region of a fusion device through the organic synergy of technical elements such as precise temperature control, cluster size feedback, and dynamic parameter correction. It not only improves the feeding efficiency per unit injection volume but also enables the injection process to have higher spatiotemporal precision control capabilities and operational flexibility, providing reliable technical support for the diversified needs of fusion experiments and the efficient and stable operation of future fusion reactors. Attached Figure Description

[0022] The present invention is described in detail with reference to the following figures, which include four figures as follows: Figure 1 This is a schematic diagram illustrating the mapping relationship between temperature and cluster size under different gas source pressures, as obtained from the study. Figure 2 This is a schematic diagram of the constituent units of the ultrasonic molecular beam cryogenic injection system of the present invention; Figure 3 This is a schematic diagram showing the structural connection between the injection unit and the cold head integration in the system of the present invention; Figure 4 This is an exemplary flowchart of the ultrasonic molecular beam cryogenic injection method of the present invention.

[0023] The meanings of the markings in the attached diagram are as follows: 100 - Intelligent Control Processing Unit; 200 - Gas supply and pressure regulation unit; 210 - Gas cylinder and gas pipe; 220 - Valve assembly; 230 - Gas storage tank; 240 - Automatic pressure controller; 300 - Helium refrigeration unit, 310 - Helium compressor, 320 - Helium pipe, 330 - Cold head; 400 - Temperature control unit, 410 - Temperature controller, 420 - Thermometer, 430 - Heater; 500 - Injection unit, 510 - Steel gas pipeline, 520 - Solenoid valve and Laval nozzle, 530 - Copper adapter; 600 - Cluster measurement unit, 610 - Laser, 620 - Optical lens group, 630 - Synchronizer, 640 - Signal receiving device; 700-Fusion Device. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0026] Example 1 like Figure 1 As shown, an ultrasonic molecular beam cryogenic injection system based on cluster size feedback control is disclosed. The system includes a gas supply and pressure regulation unit 200, a helium cooling unit 300, a temperature control unit 400, an injection unit 500, a cluster measurement unit 600, and an intelligent control and processing unit 100. The gas supply and pressure regulation unit 200 is in fluid communication with the injection unit 500 and is used to provide gas supply and regulate the pressure of the injected gas; The cold end of the helium cooling unit 300 is thermally coupled to the injection unit 500 to provide cryogenic cooling to the injection unit 500; The temperature control unit 400 is connected to the injection unit 500 and is used to adjust the gas temperature of the injection unit 500; The injection unit 500 is configured to generate an ultrasonic molecular beam and inject it into the fusion device 700 under set pressure and set temperature conditions; The cluster measurement unit 600 is configured to detect the cluster size of the ultrasonic molecular beam generated by the injection unit 500 and output a cluster size signal; The intelligent control processing unit 100 is connected to the gas supply and pressure regulation unit 200, the helium cooling unit 300, the temperature control unit 400, the injection unit 500, and the cluster measurement unit 600, respectively. The intelligent control processing unit 100 is configured to receive cluster size signals and, based on preset cluster size target values, output pressure adjustment commands to the gas supply and pressure regulation unit 200 and temperature adjustment commands to the temperature control unit 400, so that the actual cluster size of the ultrasonic molecular beam generated by the injection unit 500 approaches the cluster size target value.

[0027] This embodiment will provide a detailed and optimized description of each component unit in the above system.

[0028] As a preferred embodiment, the gas supply and pressure regulation unit 200 is supplied by a high-pressure gas source (including...) Figure 1 The system comprises a gas cylinder and gas pipe 210, a valve assembly 220 for pre-pressure regulation, a gas storage tank 230, an automatic pressure controller 240, and a safety relief device. Fuel gas from a high-pressure gas source is transported via a stainless steel gas pipe to the pressure regulating valve assembly 220, which initially reduces the gas pressure before introducing it into the gas storage tank 230. The gas storage tank 230 buffers the gas flow and stabilizes the supply pressure. The outlet of the gas storage tank 230 is connected to the automatic pressure controller 240, and its output end forms a fluid path with the inlet of the injection unit 500 through a stainless steel pipeline, enabling directional gas transmission.

[0029] The automatic pressure controller 240 establishes a signal connection with the intelligent control processing unit 100, enabling it to receive pressure adjustment commands from the system and adjust the valve opening in real time based on built-in pressure sensor feedback, ensuring the output gas pressure is precisely maintained at the set value. In this embodiment, the pressure regulating valve assembly 220 may include a multi-stage pressure reducing valve structure to smoothly transition the high-pressure gas source pressure to the working range of the gas storage tank 230, avoiding pressure surges. A safety relief device is integrated into the gas storage tank 230 or a key pipeline node, automatically opening when the system pressure exceeds a preset safety threshold, guiding excess gas to a safe area for discharge, ensuring equipment and operational safety. The entire unit adopts an all-metal sealed pipeline design, effectively suppressing gas leakage and impurity infiltration, ensuring the purity and reliability of the fuel gas transmission process, and providing stable and controllable gas input conditions for subsequent cryogenic cluster formation.

[0030] In a preferred embodiment, the helium cooling unit 300 comprises a helium compressor 310, a helium pipe 320, and a cold head 330, forming a complete thermodynamic cycle subsystem. The helium compressor 310, as the power core, continuously delivers high-pressure helium gas via the helium pipe 320 to the cold head 330. The cold head 330 generates low-temperature cooling capacity during helium throttling expansion or cyclic refrigeration. The cooling end face of the cold head 330 is connected to the copper base of the injection unit 500 (in... Figure 1 The copper adapter 530 in the middle achieves close surface contact, forming a low thermal resistance thermal coupling path between the two, so that the cold energy can be efficiently transferred to the gas flow channel inside the injection unit 500.

[0031] In this embodiment, the cold head 330 adopts a standardized flange structure, which is rigidly connected to the vacuum chamber port by bolts and a vacuum sealing ring to ensure the structural stability and system sealing reliability of cold transfer in a vacuum environment. The entire helium cooling unit 300 uses helium as the working medium to construct a closed-loop refrigeration cycle, providing a continuous and stable low-temperature environment for the injection unit 500. Its flange assembly design facilitates installation and maintenance in the vacuum system, while the copper transition structure effectively ensures the uniformity and response speed of low-temperature conduction. Figure 3 The connection between the cold head 330 and the injection unit 500 in the helium cooling unit 300 is shown, which can be viewed and understood simultaneously.

[0032] In a preferred embodiment, the temperature control unit 400 comprises a temperature controller 410, a high-precision thermometer 420, and a high-power heater 430. The high-precision thermometer 420 and the high-power heater 430 are integrated into the outer wall of the copper adapter 530 of the injection unit 500 via embedded or surface-mount methods, enabling real-time sensing and thermal intervention of the gas flow channel area. The temperature controller 410 establishes electrical connections with the thermometer 420, the heater 430, and the intelligent control processing unit 100 via signal cables, forming a complete thermal control loop.

[0033] During operation, the temperature controller 410 continuously collects the real-time temperature signal fed back by the thermometer 420, and dynamically calculates and outputs the corresponding power control signal to the heater 430 based on the temperature adjustment command issued by the intelligent control processing unit 100. The controllable heat generated by the heater 430 and the cooling capacity conducted by the helium cooling unit 300 through the copper base achieve dynamic thermal balance inside the copper base, so that the temperature of the injected gas is stably maintained at the set value.

[0034] In this embodiment, the temperature control unit 400 supports remote software setting and monitoring. The recommended temperature adjustment range is 10 to 325K, and the temperature control accuracy should be better than 0.1K. The dynamic thermal balance between heat and cold is achieved by the temperature controller 410 adjusting the heating power in real time through algorithms such as PID, so that the heating flow and the cooling flow reach an instantaneous cancellation state at the set temperature point, thereby achieving undisturbed and precise temperature maintenance.

[0035] In this preferred embodiment, the injection unit 500 is the core actuator for the generation and output of the ultrasonic molecular beam, and consists of a vacuum chamber, a copper gas supply pipeline 510, a solenoid valve, a Laval nozzle 520, and a copper adapter 530. The vacuum chamber is a sealed cavity structure with an air inlet on its side wall. This air inlet is connected to the outlet of the gas supply and pressure regulation unit 200 via a pipeline to introduce pressure-regulated gas. The Laval nozzle is fixedly installed at the front end of the vacuum chamber cavity, with its nozzle facing the vacuum area of ​​the fusion device 700. The nozzle body and the copper base are rigidly connected by threads or flanges to ensure structural stability and continuous heat conduction. The injection unit 500 and the fusion device 700 can be specifically connected via a vacuum pipeline and a gate valve. Before connection and installation, leak rate, magnetic permeability, and other tests must be met before proceeding.

[0036] The copper adapter 530 is integrally machined from high-purity oxygen-free copper, with an internal flow channel chamber matching the gas delivery pipeline. The gas delivery pipeline and solenoid valve are integrally embedded and tightly fitted inside the copper adapter, forming a complete thermal contact interface. The rear end of the copper adapter achieves surface-to-surface thermal coupling with the cold head 330 of the helium cooling unit 300 through a copper adapter structure, ensuring uniform transfer of cryogenic cooling energy throughout the gas flow area. All gas delivery pipelines within the vacuum chamber are made of copper, effectively reducing thermal resistance and maintaining the stability of the cryogenic environment, avoiding localized temperature rises due to differences in material thermal conductivity.

[0037] The solenoid valve, acting as a gas on / off control element, has its valve core activated by an external control signal to precisely regulate the start and duration of gas injection. The Laval nozzle features a special nozzle structure with a cross-section that contracts before expanding; its geometry is optimized for fluid dynamics, enabling the high-pressure, low-temperature gas to accelerate and expand during flow, forming a supersonic molecular beam. A multi-needle vacuum penetrator is embedded in the vacuum chamber wall, integrating multiple sets of high-vacuum compatible electrical leads. One end connects to the thermometer 420 leads and solenoid valve control terminals mounted on the copper base, while the other end interfaces with the external intelligent control processing unit 100, ensuring reliable transmission of control signals and sensor data while maintaining the integrity of the vacuum seal.

[0038] In a preferred embodiment, the cluster measurement unit 600 employs an optical detection structure based on the Rayleigh scattering principle for non-contact, real-time characterization of cluster sizes in ultrasonic molecular beams. The cluster measurement unit 600 comprises a laser 610, an optical mirror assembly 620, a synchronizer 630, and a signal receiving device 640. The laser 610 is a solid-state laser operating in long-pulse mode, emitting a continuous probe beam with a wavelength adapted to the cluster scattering characteristics. The optical mirror assembly 620 includes a reflector, a focusing lens, and an optical path adjustment bracket. The probe beam is precisely guided through a quartz optical window on the sidewall of the vacuum chamber to the measurement region downstream of the Laval nozzle outlet, creating a stable cross-interaction zone between the beam and the ejected molecular beam.

[0039] When the probe light interacts with cluster particles in the molecular beam, according to Rayleigh scattering theory, under the condition that the incident light wavelength is much larger than the characteristic size of the particles, the intensity of the scattered light is quantitatively related to the square of the cluster particle volume. The signal receiving device 640, composed of a high-sensitivity photomultiplier tube or avalanche photodiode, along with a bandpass filter and signal conditioning circuitry, directionally collects the scattered light and converts it into an analog electrical signal. This signal is then sent to the intelligent control processing unit 100 via a shielded transmission line for digital processing and size analysis. The synchronizer 630, as the timing coordination core, is interconnected with the intelligent control processing unit 100 to generate a synchronization trigger pulse. This pulse uniformly controls the light emission time of the laser 610, the opening timing of the solenoid valve in the injection unit 500, and the sampling window of the signal receiving device 640, ensuring strict synchronization between the scattered signal acquisition and the molecular beam ejection process.

[0040] In this embodiment, the cluster measurement unit 600 supports dual-mode operation of real-time closed-loop monitoring and offline calibration analysis. The quartz window in the optical path possesses high light transmittance and vacuum sealing characteristics, and the mirror assembly support adopts a three-dimensional adjustable structure to adapt to different optical path calibration requirements. The field of view and measurement area of ​​the signal receiving device 640 are optically calibrated to effectively suppress background stray light interference, ensuring the accuracy and repeatability of scattered signal acquisition and providing a stable and reliable cluster size feedback data source for the system.

[0041] In this preferred embodiment, the intelligent control processing unit 100 is the core control hub of the system, which can specifically integrate a data processing module, a control algorithm module, and a human-machine interface. The intelligent control processing unit 100 has a built-in multi-parameter mapping relationship database, which covers various working gases such as hydrogen, deuterium, and argon. For each gas, a multi-dimensional correlation dataset is established between gas type, pressure range, nozzle structure parameters, target cluster size, and corresponding gas temperature. The mapping relationship is constructed based on offline calibration experimental data and is reflected as a nonlinear correlation model in the form of piecewise functions or lookup tables, rather than a single empirical formula.

[0042] During system operation, the intelligent control processing unit 100 receives the target cluster size, gas type, and pressure setpoint input via the human-machine interface. It first verifies whether each parameter is within the preset adjustable parameter boundaries. If any parameter exceeds the system's capability range, a warning signal is generated and displayed on the interface. After the parameter verification is successful, the unit calls the multi-parameter mapping database, matches the temperature reference value corresponding to the current operating condition, and generates initial pressure adjustment commands and temperature adjustment commands, which are sent to the gas supply and pressure regulation unit 200 and the temperature control unit 400, respectively.

[0043] During the injection process, the intelligent control processing unit 100 continuously receives the cluster size signal fed back by the cluster measurement unit 600, calculates the deviation between this signal and the target cluster size value in real time, and dynamically corrects the output values ​​of the pressure adjustment command and temperature regulation command according to the preset PID control logic or fuzzy adaptive algorithm to achieve cluster size tracking control. At the same time, the intelligent control processing unit 100 associates and stores the set pressure, measured temperature, measured cluster size and nozzle operating parameters corresponding to a single injection, and uses a weighted recursive algorithm to update the mapping parameters of the corresponding operating node in the database online, so that the mapping relationship is continuously optimized as the operating data accumulates.

[0044] In this embodiment, the intelligent control processing unit 100 supports switching between automatic and manual control modes. In automatic mode, the system executes a feedback adjustment process throughout; in manual mode, the operator can directly set pressure and temperature parameters, and the intelligent control processing unit 100 only performs command forwarding and data recording functions. The control algorithm module of this unit can reserve a custom algorithm interface, allowing customized control strategies to be loaded according to specific experimental needs, enhancing the system's applicability and flexibility under complex working conditions. All operating parameters, measurement data, and database update records are stored in the unit's internal storage medium, supporting historical data traceability and offline analysis.

[0045] Example 2 Based on Example 1, this example provides a cryogenic ultrasonic molecular beam injection method based on cluster size feedback control. The hardware basis of this method is the cryogenic ultrasonic molecular beam injection system in Example 1. The key steps of this method can be summarized as follows: S1, Target value for receiving cluster size; S2. Based on the target value of cluster size, generate pressure regulation command and temperature adjustment command; S3. According to the pressure adjustment command, control the gas supply and pressure regulation unit 200 to adjust the pressure of the injected gas; according to the temperature regulation command, control the temperature control unit 400 to adjust the gas temperature of the injection unit 500. S4. After the pressure and gas temperature reach the set conditions, control the injection unit 500 to generate an ultrasonic molecular beam and inject it into the fusion device 700. S5. The actual cluster size of the ultrasonic molecular beam is synchronously acquired through the cluster measurement unit 600, and a cluster size signal is generated. S6. Compare the cluster size signal with the target cluster size value, update the pressure adjustment command and / or temperature adjustment command according to the comparison result, and return to step S3 to repeat until the injection process ends.

[0046] This embodiment will provide a detailed description of the process and preferred methods described above. The exemplary preferred detailed process can be viewed concurrently. Figure 4 The illustration.

[0047] In this embodiment, after the system is powered on, it first completes the initialization self-test of each unit to ensure that the gas supply and pressure regulation unit 200, helium cooling unit 300, temperature control unit 400, injection unit 500, and cluster measurement unit 600 are in normal standby mode. The operator sets the working gas type, gas pressure setpoint, and cluster size target value through the human-machine interface. The intelligent control processing unit 100 receives the above parameters and performs validity verification. The verification includes whether the parameters fall within the system's preset adjustable parameter range. This range is jointly defined by the hardware capability boundary and the coverage area of ​​the multi-parameter mapping relationship database. If any parameter exceeds the valid range, the system immediately generates an audible and visual warning signal and terminates the subsequent process.

[0048] After successful verification, the intelligent control processing unit 100 calls upon its built-in multi-parameter mapping database. This database stores data on the correlation between cluster size and gas temperature for different gases such as hydrogen, deuterium, and argon under specific pressure ranges and nozzle operating conditions. Based on this data, it calculates and generates initial pressure adjustment commands and temperature adjustment commands. The pressure adjustment command is transmitted to the automatic pressure controller 240 of the gas supply and pressure regulation unit 200, driving it to adjust the output pressure. The temperature adjustment command is transmitted to the temperature controller 410 of the temperature control unit 400. The temperature controller 410 dynamically adjusts the power of the heater 430, ensuring that the heating heat flow and the cooling flow provided by the helium cooling unit 300 achieve thermal equilibrium within the copper base, stabilizing the gas temperature at the target value.

[0049] Once the pressure and temperature have reached and stabilized at the set thresholds, the intelligent control processing unit 100 sends an opening pulse signal to the solenoid valve of the injection unit 500, simultaneously triggering the synchronizer 630 to generate a timing control signal. The synchronizer 630 coordinates the laser 610 emission time of the cluster measurement unit 600, the sampling window of the signal receiving device 640, and the solenoid valve opening time to ensure strict synchronization, guaranteeing the acquisition of scattered light signals during molecular beam ejection. The signal receiving device 640 transmits the converted electrical signal back to the intelligent control processing unit 100, where the data processing module analyzes the signal to obtain the actual cluster size signal.

[0050] The intelligent control processing unit 100 compares the actual cluster size signal with the target cluster size value in real time, calculates the deviation based on a preset control algorithm, and dynamically corrects the output parameters of the pressure regulation command and temperature control command. After the command is updated, it is re-applied to the gas supply and pressure regulation unit 200 and the temperature control unit 400, forming a continuous regulation process. This feedback regulation cycle is executed until the end of a single injection pulse. The cluster measurement function can be enabled or disabled as needed, suitable for monitoring requirements in different experimental scenarios.

[0051] After each injection, the system timestamps and stores the gas type, set pressure, measured temperature, measured cluster size, and nozzle operating parameters. It then uses a recursive averaging or weighted fitting algorithm to update and correct the mapping parameters of the corresponding operating node in the multi-parameter mapping database online. This mechanism allows the database to continuously optimize with the accumulation of operational data, enhancing the system's adaptability to different gases and operating conditions. The entire control process supports switching between automatic and manual parameter setting modes, meeting the dual requirements of experimental flexibility and process reproducibility.

[0052] This embodiment will now use specific numerical examples to illustrate the complete injection process for the fusion device. The experimental gas used is deuterium, and the gas source pressure is set to 40 × 10⁻⁶. 5 Pa, with a target cluster size of 3000 units.

[0053] The system is initialized, confirming that the high-pressure deuterium in the gas cylinder and gas pipe 210, as well as the helium cooling unit 300, are in normal working condition. On the human-machine interface of the intelligent control processing unit 100, the gas type is selected as deuterium, and the target gas source pressure is input: 40 × 10⁻⁶. 5 Pa, verification successful with no error alarms, click Execute. The system will send the pressure control sequence to the gas supply and pressure regulation unit 200.

[0054] The valve assembly 220 of the gas supply and pressure regulation unit 200 opens, supplying gas to the storage tank 230 at a pre-depressurized pressure of 50 × 10⁻⁶. 5 After deuterium gas is introduced into Pa, valve assembly 220 is closed; automatic pressure controller 240 is activated, and gas is supplied to the injection unit through stainless steel piping until the pressure stabilizes at 40 × 10⁻⁶ Pa. 5 After Pa, turn off the automatic pressure controller 240.

[0055] When the cluster size target of 3000 units is entered into the human-machine interface of the intelligent control processing unit 100, the intelligent control processing unit 100 calls the temperature-cluster size mapping relationship in the internal memory, calculates the current required temperature of 50K according to the set air source pressure, and verifies it. If the target temperature is within the system adjustment range, after the pop-up confirmation, the temperature control sequence command is sent to the temperature control unit 400.

[0056] In the temperature control unit 400, the temperature controller 410 controls the output power of the heater 430 and monitors the real-time data of the thermometer 420. After the heat of the heater 430 and the cooling capacity of the cold head 330 in the helium cooling unit 300 reach a balance, the target set temperature value is reached and maintained.

[0057] After inputting the injection start time, pulse width, and frequency parameters into the human-machine interface of the intelligent control processing unit 100, the solenoid valve 520 of the injection unit 500 is activated. The beam undergoes adiabatic expansion through the Laval nozzle 530 to form an ultrasonic molecular cluster beam, which is then injected into the fusion device 700.

[0058] Before the pulse sequence number is sent to the injection unit 500 through the human-machine interface of the intelligent control processing unit 100, the cluster measurement unit 600 is activated, and the synchronizer 630 will synchronously trigger the laser 610. The optical lens group 620 is fixed after the optical path adjustment is completed and does not need to be adjusted each time. The signal receiving device 640 transmits the scattered light intensity signal back to the intelligent control processing unit 100 to complete the cluster measurement. The intelligent control processing unit 100 calculates the size of the injected cluster based on the scattered light signal and the built-in algorithm. After the measurement result is confirmed and agreed upon, it can be uploaded to the memory to correct the temperature-cluster size mapping curve.

Claims

1. A cryogenic ultrasonic molecular beam injection system based on cluster size feedback control, characterized in that, The system includes a gas supply and pressure regulation unit, a helium cooling unit, a temperature control unit, an injection unit, a cluster measurement unit, and an intelligent control and processing unit; The gas supply and pressure regulation unit is in fluid communication with the injection unit and is used to provide gas supply and regulate the pressure of the injected gas; The cold end of the helium cooling unit is thermally coupled to the injection unit to provide cryogenic cooling to the injection unit; The temperature control unit is connected to the injection unit and is used to adjust the gas temperature of the injection unit; The injection unit is configured to generate an ultrasonic molecular beam and inject it into the fusion device under set pressure and temperature conditions. The cluster measurement unit is configured to detect the cluster size of the ultrasonic molecular beam generated by the injection unit and output a cluster size signal; The intelligent control processing unit is connected to the gas supply and pressure regulation unit, the helium cooling unit, the temperature control unit, the injection unit, and the cluster measurement unit. The intelligent control processing unit is configured to receive the cluster size signal and, based on a preset cluster size target value, output a pressure adjustment command to the gas supply and pressure regulation unit and a temperature adjustment command to the temperature control unit, so that the actual cluster size of the ultrasonic molecular beam generated by the injection unit approaches the cluster size target value.

2. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The gas supply and pressure regulation unit includes a high-pressure gas source, a valve assembly, a gas storage tank, an automatic pressure controller, and a safety relief device. The high-pressure gas source is connected to the gas storage tank via a gas pipe. The valve assembly is installed on the gas pipe between the high-pressure gas source and the gas storage tank to initially reduce the pressure of the gas from the high-pressure gas source. The outlet of the gas storage tank is connected to the automatic pressure controller, and the outlet of the automatic pressure controller is in fluid communication with the inlet of the injection unit. The automatic pressure controller is also signal-connected to the intelligent control processing unit to receive pressure adjustment commands and maintain the set pressure in real time. The safety relief device is used to release gas from the gas supply and pressure regulation unit under preset safety conditions.

3. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The helium cooling unit includes a helium compressor, a helium pipe, and a cold head. The helium compressor delivers the working medium to the cold head through the helium pipe. The cold head is attached to the copper seat of the injection unit via a copper adapter to form a thermal coupling path. The cold head is fixedly connected to the vacuum chamber of the injection unit using a flange-type assembly structure, so that the low-temperature cooling capacity is conducted to the injection unit.

4. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The temperature control unit includes a temperature controller, a thermometer, and a heater; the thermometer and the heater are integrated and installed on the copper base surface of the injection unit; the temperature controller is signal-connected to the intelligent control processing unit; the temperature controller is configured to control the output power of the heater according to the received temperature adjustment command, so that the heat generated by the heater and the cooling provided by the helium cooling unit reach a dynamic balance, and control the gas temperature in the injection unit at a set value.

5. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The injection unit includes a vacuum chamber, a gas supply line, a solenoid valve, a Laval nozzle, and a copper base; the copper base encloses the gas supply line and the solenoid valve, and the Laval nozzle is disposed in the vacuum chamber and fixedly connected to the copper base; the vacuum chamber is provided with an air inlet that communicates with the gas supply and pressure regulation unit; the injection unit also uses a multi-needle vacuum penetrator to achieve signal connection between the device control circuit inside the vacuum chamber and the intelligent control processing unit.

6. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The cluster measurement unit includes a laser, an optical lens group, a synchronizer, and a signal receiving device. The optical lens group guides the probe light emitted by the laser to the Laval nozzle exit region of the injection unit, so that the probe light interacts with the ejected ultrasonic molecular beam to generate scattered light. The signal receiving device collects the scattered light signal and converts it into an electrical signal, which is then output to the intelligent control and processing unit. The synchronizer is signal-connected to the intelligent control and processing unit and is used to coordinate and control the triggering time of the laser, the opening time of the solenoid valve in the injection unit, and the sampling timing of the signal receiving device.

7. The ultrasonic molecular beam cryogenic injection system according to claim 1, characterized in that: The intelligent control processing unit has a built-in database of multi-parameter mapping relationships between cluster size and temperature. The database is constructed based on different gas types and associated with pressure ranges and nozzle operating parameters. The intelligent control processing unit is also configured to update and correct the corresponding parameters in the database online based on the cluster size signal fed back by the cluster measurement unit.

8. The ultrasonic molecular beam cryogenic injection system according to claim 7, characterized in that: The intelligent control processing unit is further configured to, after receiving the cluster size target value set by the user, verify whether it is within the adjustable parameter range of the system; if it exceeds the range, it generates an early warning signal. During the ultrasonic molecular beam injection process, the intelligent control processing unit dynamically adjusts the pressure adjustment command sent to the gas supply and pressure regulation unit and the temperature regulation command sent to the temperature control unit based on the deviation between the cluster size signal fed back by the cluster measurement unit in real time and the cluster size target value.

9. A method for cryogenic injection of ultrasonic molecular beams according to claim 1, characterized in that, The method includes the following steps: S1, Target value for receiving cluster size; S2. Based on the target value of the cluster size, generate pressure adjustment command and temperature adjustment command; S3. According to the pressure adjustment command, control the gas supply and pressure regulation unit to adjust the pressure of the injected gas; according to the temperature regulation command, control the temperature control unit to adjust the gas temperature of the injected unit. S4. After the pressure and gas temperature reach the set conditions, control the injection unit to generate an ultrasonic molecular beam and inject it into the fusion device; S5. The actual cluster size of the ultrasonic molecular beam is synchronously acquired through the cluster measurement unit, and a cluster size signal is generated. S6. Compare the cluster size signal with the cluster size target value, update the pressure adjustment command and / or the temperature adjustment command according to the comparison result, and return to step S3 to repeat until the injection process ends.

10. The cryogenic injection method for ultrasonic molecular beams according to claim 9, characterized in that: In step S1, gas type information and gas pressure setpoint are received synchronously. In step S2, before generating the pressure adjustment command and the temperature adjustment command, it is verified whether the cluster size target value, the gas type information, and the gas pressure setpoint are within the system's preset adjustable parameter range. If they exceed the range, a warning signal is generated. In step S6, all data related to the gas pressure, gas temperature, and actual cluster size corresponding to this injection are associated and stored, and the multi-parameter mapping relationship database of cluster size and temperature built into the intelligent control processing unit is updated and corrected online.

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