A cold cathode ray detection control system

Abstract

The application discloses a cold cathode ray detection control system, which comprises a ray tube with a cold cathode, a power module, and a control module for modulating and boosting the power module and providing excitation X rays to the ray tube for detection, wherein the control module comprises a master control and calculation module MCC, the master control and calculation module MCC is bidirectionally connected with a high-frequency high-voltage inverter and modulation module HFHI, a pulse driving and field emission control module FDEC, a precision sensing and acquisition module PSA, a safety interlocking and state monitoring module SISM and a human-computer interface and communication module HCI through a high-speed digital control bus. According to the application, the corresponding delay is reduced from the traditional 100us level to below 5us through algorithm optimization, the speed is significantly improved, and pulse-level real-time regulation can be realized. Meanwhile, the current and voltage precision regulation is also significantly improved, and the accurate and stable output of the dose can be realized.

Description

Technical Field

[0001] This invention relates to the field of radiation detection technology, and more particularly to the field of portable outdoor radiation detection devices and control systems using cold cathodes, specifically to a cold cathode radiation detection control system. Background Technology

[0002] In the field of nondestructive testing (NDT), X-rays, with their powerful penetrating ability and precise control of radiation dosage, have become one of the most widely used techniques in medicine, industry, and materials science. The core equipment is called an X-ray machine or X-ray source generator, which typically works in conjunction with a detector: the detector receives the X-rays that penetrate the target object and creates an image, thereby revealing its internal structure and achieving the purpose of NDT.

[0003] X-rays are generated by high-speed electrons colliding with the atomic nuclei of a target material. When electrons are attracted by the strong Coulomb field of the atomic nucleus and decelerate rapidly, the lost kinetic energy is radiated as photons, forming X-rays. Based on the principle of electron emission, X-ray sources can be divided into two categories: hot cathodes and cold cathodes. Hot cathode X-ray sources heat the cathode material to a high temperature of approximately 2000°C, allowing electrons to gain sufficient kinetic energy to overcome the work function and form an electron cloud. This process requires continuous power to maintain the high temperature, resulting in high energy consumption. In contrast, cold cathode X-ray sources directly strip electrons from the surface of the cathode material using a strong electric field or electron bombardment, eliminating the need for heating and significantly reducing energy consumption. For portable detection applications (such as outdoor mobile detection, handheld X-ray fluorescence analyzers, pulsed X-ray detection, and other scientific research, experimental, and security inspection scenarios), hot cathode X-ray machines are unsuitable due to their high energy consumption and heat dissipation requirements. Therefore, the development of portable cold cathode X-ray machines is urgently needed.

[0004] Traditional portable cold cathode X-ray machines typically employ power frequency or intermediate frequency inverter topologies based on silicon-based IGBTs or MOSFETs for their high-voltage power supplies. Limited by the switching losses and frequency characteristics of semiconductor devices, their operating frequencies are usually below 50kHz, resulting in bulky transformers and filter components, and power density that struggles to exceed 1kW / kg. This severely hinders the improvement of equipment lightweighting and portability. Furthermore, existing control systems largely rely on analog circuits or fixed-parameter digital PWM regulation, offering narrow adjustment ranges for pulse width and repetition frequency, and lacking adaptive capabilities to the cold cathode field emission characteristics.

[0005] This rigid control mode leads to three core problems: First, the transient instability of cathode electron emission causes X-ray dose rate drift, resulting in image grayscale distortion; second, the thermal diffusion of the electron beam focus under wide pulse operation limits the spatial resolution to below 3 LP / mm, which cannot meet the requirements for microstructure detection; and third, continuous overcurrent impact significantly shortens the cathode lifetime.

[0006] Furthermore, the high-voltage closed-loop response delay of existing power supply topologies exceeds 100μs, making it impossible to achieve pulse-level real-time control, which further exacerbates the uncontrollability of output energy.

[0007] Although recent research has attempted to introduce digital control chips, the algorithms have only achieved open-loop pulse width modulation, failing to establish a multi-parameter collaborative mechanism for cathode state and dose feedback, and even more so failing to resolve the core contradiction of deep integration between high frequency and digitalization. Therefore, there is an urgent need for a new control system that integrates wide-bandgap semiconductor high-frequency inverter technology with intelligent adaptive pulse modulation, which can overcome the technical bottlenecks of power density, resolution, and reliability through topological innovation and algorithmic synergy. Summary of the Invention

[0008] To address the challenges of miniaturized structural design and high-frequency, digitally integrated control systems for cold cathode ray detection equipment, this application provides a cold cathode ray detection control system. It offers various structured design schemes for cold cathode ray detection devices to meet the needs of existing outdoor detection scenarios. Furthermore, through algorithm improvements, adaptive dose control can be achieved, balancing image clarity with radiation safety. Additionally, the use of a high-speed digital signal processor enables precise closed-loop control of high voltage, enhancing stability and anti-interference capabilities.

[0009] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0010] A cold cathode X-ray detection and control system includes an X-ray tube with a cold cathode, a power supply module, and a control module that modulates and boosts the power supply module to provide excitation X-rays to the X-ray tube for detection. The control module includes a main control and computing module (MCC), which is bidirectionally connected via a high-speed digital control bus to a high-frequency high-voltage inverter and modulation module (HFHI), a pulse drive and field emission control module (FDEC), a precision sensing and acquisition module (PSA), a safety interlock and status monitoring module (SISM), and a human-machine interface and communication module (HCI). The high-voltage pulse output from the HFHI module... The input terminal of the pulse drive and field emission control module FDEC is connected, and the output terminal of the pulse drive and field emission control module FDEC is connected to the cold cathode; the precision sensing and acquisition module PSA is connected to a voltage sensor, a current sensor, a dose rate sensor, and a temperature sensor through a precision analog front-end circuit AFE; the safety interlock and status monitoring module SISM is connected to a door switch, an emergency stop button, a vacuum gauge relay, an audible and visual alarm, and a safety relay through digital I / O or simple analog connections.

[0011] The ray tube includes a vacuum-equipped tube body and cold cathode and anode targets located at both ends inside the tube body. The tube body includes, from the inside out, an inner surface layer made of electropolished Kovar alloy, a ceramic-metal sealing layer, a ceramic insulating ring layer, a polyethylene layer, and a radiation shielding layer. The inner surface layer forms a vacuum electric field acceleration cavity for electron acceleration.

[0012] As an optional preferred embodiment of the present invention, the inner surface layer is a 1mm thick Fe-Ni-Co alloy; the ceramic-metal sealing layer consists of a metallized layer formed by sintering molybdenum-manganese powder, a nickel-plated transition layer, and a gold-germanium eutectic brazing layer arranged sequentially; the ceramic insulating ring layer is a 2mm thick 96% alumina ceramic; the external cooling layer is a composite structure of 316L stainless steel covering 0.8mm×1.2mm microchannels; and the radiation shielding layer is an integral structure composed of tungsten-nickel alloy or lead particles.

[0013] In terms of control, preferably, the control module includes a main control and computing module (MCC) for receiving instructions from the human-machine interface and communication module (HCI) in real time, as well as receiving real-time data from the precision sensing and acquisition module (PSA) and the safety interlock and status monitoring module (SISM), and performing adaptive pulse parameter adjustments. , , The adaptive pulse parameters are calculated and dose management is performed. , , The algorithm used for the calculation is as follows:

[0014]

[0015] in, The pulse amplitude set voltage value calculated in the kth control cycle is represented by V; This represents the desired transmit current value. This represents the average emission current measured during the kth control cycle, in amperes (A). , Represents proportional and integral gain; ∑ represents the control cycle time, in seconds; ∑ represents the integral of the error from the start to the current cycle k.

[0016]

[0017]

[0018] in, The duration of a single high-voltage pulse, measured in microseconds (µs) or nanoseconds (ns). It is the pulse width calibration coefficient, which is determined by the cathode characteristics; is the system reference resolution, is the actual required resolution, with the unit of LP / mm;

[0019] represents the repetition frequency of the pulse sequence, with the unit of Hz or kHz; is the frequency scaling factor, which is determined by the response speed of the high-voltage power supply, is the equivalent attenuation coefficient of the target material; is the equivalent attenuation coefficient of the detected material.

[0020] Preferably, the high-frequency high-voltage inversion and modulation module HFHI includes a digital controller for receiving instructions from the master control and calculation module and generating PWM / pulse control signals, a wide-bandgap semiconductor driver for providing isolation protection, a wide-bandgap semiconductor power stage module for core power conversion, a high-frequency power transformer for boosting with high frequency, high efficiency, and high insulation voltage, and a multi-stage sampling resonant network module for proportionally reducing the sampled anode high voltage to the low-voltage measurable range , and performing filtering processing; the multi-stage sampling resonant network module in the high-frequency high-voltage inversion and modulation module uses an LLC resonant converter to output voltage obtained by the following formula:

[0021]

[0022] is the output DC bus voltage, is the input DC voltage, unit: V; N represents the transformer secondary / primary turn ratio; M is the voltage gain, related to the switching frequency; Q is the quality factor; ; is the normalized frequency, ; is the resonant frequency, .

[0023] Preferably, replace the LLC resonant converter used in the multi-stage sampling resonant network module with a PWM duty cycle control model, and the calculation method of the output voltage is as follows:

[0024]

[0025] Among them, is the topology factor, when the full-bridge structure , N is the transformer secondary / primary turn ratio; represents the PWM signal duty cycle and satisfies 0<D<1; the digital PI control algorithm is as follows:

[0026]

[0027] in, This represents the duty cycle setting for the k-th cycle; This is the anode voltage feedback in the kth cycle, in V. , These represent the voltage loop proportional gain and integral gain, respectively. Represents the control period, in seconds.

[0028] Preferably, the pulse drive and field emission control module (FDEC) includes a function for receiving high-voltage pulses output from the high-frequency high-voltage inverter and modulation module. It also includes a pulse interface and logic unit for logic on / off control, providing precise and fast-response gate voltage. Or extract pressure The gate / extraction electrode control circuit for the cold cathode provides the DC bias potential of the cathode and the local feedback signal for stabilizing field emission. The cathode bias and stabilization circuit is used to measure the cathode emission current. The emission current sampling circuit and the instructions from the main control and computing module control the gate / extraction electrode drive circuit, and read the cathode emission current. The microcontroller logic unit calculates the emission stability index and communicates with the main control and computing modules in real time; the gate / extractor control circuit in the pulse drive and field emission control module controls the field emission current density. J The equation is as follows:

[0029]

[0030] in, J Represents the emission current density, unit: A / m 2 A represents the effective emission area constant, in A·m. -2 ·V -2 ; The field enhancement factor is represented by E, which represents the applied electric field strength, in V / m.

[0031] Preferably, the system further includes an X-ray machine for accommodating and fixing the X-ray tube and the power module. The X-ray machine includes caps fixedly installed at both ends of the X-ray tube. The caps are fixedly connected to the outer casing via connectors. The control module is installed between the X-ray tube and the outer casing. The power module includes a battery compartment. A battery socket is provided inside the battery compartment. Two contact pieces that are electrically connected to the control module and respectively electrically connected to the positive and negative terminals of the lithium battery are fixedly installed inside the battery socket.

[0032] To meet the complex environment of outdoor testing, the device's adaptability to outdoor environments and its portability must be considered. Preferably, the surface of the housing is also provided with an LCD screen for display or manual touch input. The LCD screen is electrically connected to the human-machine interface and communication module (HCI). A protective film is fixedly attached to the LCD screen. The housing is also provided with a patch antenna electrically connected to the main control and computing module (MCC) for wireless data or signal transmission, and an interface for connecting external transmission / power cables is provided on the side wall or end face of the housing. A key switch is provided between the control module and the lithium battery.

[0033] More preferably, the outer shell includes a main shell located in the middle and equipped with a handle, a first inner shell and a second inner shell respectively covering and splicing with both ends of the main shell, and a first outer shell and a second outer shell respectively disposed outside the first inner shell and the second inner shell for protection and equipped with heat dissipation holes.

[0034] More preferably, the outer shell includes a side wall composed of a front shell, a left shell, a rear shell and a right shell, and a top cover and a bottom cover detachably and fixedly connected to the side wall; a handle and a chassis support frame for support are fixed or hinged on any one of the side walls, and multiple buffer pads are provided on the chassis support frame.

[0035] Beneficial effects:

[0036] 1. This invention adopts a novel cold cathode structure design, which can meet the requirements of flexible portability, fast response speed, energy saving and low temperature resistance; through the built-in lithium battery, it can achieve a battery life of about 8-10 hours, solving the portability requirement for outdoor operations and fundamentally making up for the shortcomings of hot cathodes that cannot be used outdoors.

[0037] The uniquely designed multi-layer X-ray tube can balance vacuum performance, insulation, thermal expansion resistance, and strength, effectively solving the three core problems of thermal stress cracking, vacuum leakage, and electronic interference.

[0038] This invention employs a combination of "high-frequency inversion, pulse modulation, and cathode state" for closed-loop control, which technically solves the problem of poor control and independent operation of the transmitter in existing power systems, and achieves collaborative optimization between modules.

[0039] 3. This invention optimizes the algorithm to reduce the corresponding delay from the traditional 100µs level to below 5µs, significantly speeding up the process and enabling pulse-level real-time control. At the same time, it also significantly improves the accuracy of current and voltage adjustment, enabling precise and stable dose output.

[0040] 4. Based on precise control of current, voltage, and dosage, this invention can further improve spatial and temporal resolution, further reduce the smallest detectable defect, and improve dynamic imaging capability from traditional static to real-time imaging. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a system block diagram of the present invention.

[0043] Figure 2 This is an exploded view of an embodiment of the present invention.

[0044] Figure 3 yes Figure 2 Isometric view of the assembled structure.

[0045] Figure 4 yes Figure 3 Axonometric view of the reverse visual structure.

[0046] Figure 5 This is an exploded view of another embodiment of the present invention.

[0047] Figure 6 yes Figure 5 Isometric view of the assembled structure.

[0048] Figure 7 yes Figure 6 Axonometric view of the reverse visual structure.

[0049] In the diagram: 1-X-ray tube; 2-cover; 3-control module; 4-switch bracket; 5-key switch; 6-battery socket; 7-contact piece; 8-lithium battery; 9-LCD screen; 10-pattern antenna; 11-protective film; 12-battery compartment; 13-main shell; 14-chassis support frame; 15-buffer pad; 16-first inner shell; 17-first outer shell; 18-second inner shell; 19-second outer shell; 20-electric field acceleration cavity; 21-X-ray emission port; 22-interface; 23-heat dissipation hole; 24-front shell; 25-left shell; 26-rear shell; 27-right shell; 28-top cover; 29-bottom cover. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 some embodiments of this application, but not all embodiments.

[0051] The components of the embodiments of this application, which are typically described and illustrated in the accompanying drawings, can be arranged and designed in a variety of different configurations.

[0052] Therefore, the following detailed description of embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the present application.

[0053] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this application, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" indicate orientation or positional relationships based on the orientation or positional relationships shown in the figures, or the orientation or positional relationships commonly used when the product is in use, they are only for the convenience of describing this application 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.

[0055] Furthermore, the terms "first" and "second" used in the description of this application are merely for distinguishing descriptions and should not be construed as indicating or implying relative importance. Additionally, the use of terms such as "horizontal" and "vertical" in the description of this application does not imply that the component is required to be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0056] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0057] Example 1:

[0058] This embodiment provides a cold cathode ray detection and control system. The system structure is described in the appendix of the instruction manual. Figure 1 As shown, the system includes an X-ray tube 1 with a cold cathode, a power supply module, and a control module 3 that modulates and boosts the power supply module to provide excitation X-rays to the X-ray tube 1 for detection. The control module 3 includes a main control and computing module (MCC), which is bidirectionally connected via a high-speed digital control bus to a high-frequency high-voltage inverter and modulation module (HFHI), a pulse drive and field emission control module (FDEC), a precision sensing and acquisition module (PSA), a safety interlock and status monitoring module (SISM), and a human-machine interface and communication module (HCI). The high-voltage pulse output from the HFHI module... The input terminal of the pulse drive and field emission control module FDEC is connected, and the output terminal of the pulse drive and field emission control module FDEC is connected to the cold cathode; the precision sensing and acquisition module PSA is connected to a voltage sensor, a current sensor, a dose rate sensor, and a temperature sensor through a precision analog front-end circuit AFE; the safety interlock and status monitoring module SISM is connected to a door switch, an emergency stop button, a vacuum gauge relay, an audible and visual alarm, and a safety relay through digital I / O or simple analog connections.

[0059] See Figure 1 As shown, in this embodiment, the high-frequency high-voltage inverter and modulation module HFHI can communicate with the human-machine interface and communication module HCI at high speed via Ethernet, USB, CAN FD, etc. The human-machine interface and communication module HCI sends user commands, including exposure parameter presets, mode selection, and start / stop commands, to the main control and computing module MCC; while the main control and computing module MCC sends system status, real-time data, alarm information, imaging parameter suggestions, etc. to the human-machine interface and communication module HCI.

[0060] The main control and computing module (MCC) establishes a connection with the precision sensing and acquisition module (PSA). The PSA then processes the digitized sensor data, such as anode voltage. Average emission current Feedback dose rate The data is transmitted in real time to the main control and computing module (MCC).

[0061] The main control and computing module (MCC) uses a high-speed digital control bus, such as fiber-optic isolated SPI, to enable high-speed parallel transmission of high-voltage setpoints from the MCC to the HFHI. Pulse amplitude setting voltage value Duration of a single high-voltage pulse ; repetition frequency of the pulse sequence Then HFHI feeds back the actual operating status to MCC, such as the actual high voltage. and current and possible fault codes .

[0062] The MCC sends a pulse enable signal to the FDEC, fine-tuning the gate voltage / extraction pressure parameters; the FDEC feeds back the cathode status to the MCC; the SISM sends the status of all safety sensors to the MCC, such as gate interlock, dose over-limit, vacuum level, emergency stop, and other possible or necessary health monitoring indicators or early warning indicators. The HFHI outputs a high-voltage pulse. Connected to the input of the FDEC, the FDEC applies this high voltage precisely to the cold cathode.

[0063] The following is a detailed explanation of each functional module:

[0064] The main control and computing module (MCC) specifically includes an MPU main processor for adaptive pulse parameter calculation, dose management, user interface, communication protocol stack management, and data recording. In this embodiment, a high-performance multi-core ARM Cortex-A or RISC-V SoC is used, running Linux or RTOS. It also includes a real-time coprocessor FPGA connected to the MPU main processor via a high-speed bus shared memory for executing millisecond / microsecond-level real-time closed-loop control algorithms, pulse parameter calculation, and safety logic processing. Although the real-time coprocessor FPGA is not the main processor MPU, its role is irreplaceable; it is the core of the entire system's information processing. Hardware-wise, a high-speed FPGA or a real-time MCU with FPU / DSP, such as a Cortex-M7 / M4, is used to execute millisecond / microsecond-level real-time closed-loop control algorithms, pulse parameter calculation, and safety logic processing.

[0065] It communicates with the MPU via a high-speed bus, such as PCIe or AXI, and shares memory. It also uses high-speed RAM, employing traditional DDR3 / 4, and non-volatile storage using eMMC or removable SD cards for storing system configuration, calibration data, algorithm models, and runtime logs. Furthermore, it provides a precise clock source for system synchronization.

[0066] Since this system is a highly integrated system, in order to facilitate understanding by those skilled in the art and to further explain the invention, the following embodiment will focus on functional modules as units to explain their working principles and their roles in the entire system, so as to facilitate better understanding.

[0067] In terms of the overall system function, the MCC acts as the central brain, receiving HCI commands and real-time data from PSA / SISM.

[0068] It performs a large amount of core calculations, mainly including calculations based on the target dose. Target imaging characteristics, such as material attenuation coefficient or penetration power. Resolution Real-time feedback , Dynamic calculation of optimal pulse parameters , , It also includes providing setting values ​​to HFHI. and based on Perform closed-loop regulation and calculate the cumulative dose through integration. and target dose In contrast, exposure time can be controlled or pulse parameters adjusted to achieve the target dose.

[0069] The high-frequency high-voltage inverter and modulation module HFHI includes a digital controller (DCtrl) for receiving instructions from the main control and computing module and generating PWM / pulse control signals. This DCtrl is a dedicated high-voltage control ASIC or high-speed MCU / FPGA that works closely with the FPGA of the MCC. It receives instructions from the MCC, including... , , , This generates PWM / pulse control signals. A wide-bandgap semiconductor driver, abbreviated as WGD, provides isolation protection; in this embodiment, a high-speed, high-drive-capability SiC MOSFET or GaN HEMT gate driver is used.

[0070] Wide-bandgap semiconductor power stage modules (WGPs) perform core power conversion, specifically implemented using full-bridge, half-bridge, or LLC resonant inverter topologies based on SiC MOSFETs or GaN HEMTs. High-frequency power transformers (HFTs) are used for boosting voltage at high frequencies, high efficiency, and high insulation voltage, employing low-loss magnetic cores such as nanocrystalline, ferrite, and Litz wire windings; and high-voltage anode transformers are used for sampling. Reduced proportionally to the low-pressure measurable range The multi-stage sampling resonant network module, which performs filtering, specifically includes a filter using an LLC resonant topology / high-frequency rectifier filter circuit, a high-voltage sampling unit, and a primary current sampling unit; the high-voltage sampling unit uses a precision high-voltage divider resistor network to sample the anode high voltage. Reduced proportionally to the low-pressure measurable range The primary current sampling unit uses a combination of a current transformer (CT) or a low-inductance sampling resistor and an isolation amplifier to measure the primary current of the inverter. .

[0071] The main functions and working principle of HFHI include high-frequency inversion, rectification and filtering / resonant conversion, pulse modulation, and high-voltage closed-loop control; among them, the high-frequency inversion process is based on the target output voltage by DCtrl. The pulse parameters are used to generate a high-frequency PWM signal. WGD drives the WGP switch, and HFT boosts the primary low-voltage high-frequency AC to the secondary high-voltage high-frequency AC.

[0072] The rectification-filtering / resonant conversion process involves the secondary high voltage being rectified and filtered, or directly obtaining a stable high voltage through a resonant network.

[0073] The pulse modulation process involves DCtrl controlling the switching timing of WGP to modulate the stable high voltage to meet the requirements. , , Required high voltage pulse sequence.

[0074] For example, amplitude modulation can be achieved by changing the PWM duty cycle or phase shift angle, and pulse width and frequency can be controlled by switching timing.

[0075] The high-voltage closed-loop control process includes reading via DCtrl. (represent = * ) and with By comparing and adjusting PWM parameters in real time, such as duty cycle D, switching frequency, or phase shift angle, the output voltage can be stabilized.

[0076] The Field Emission Driver & Control Module (FDEC), used in the embodiments section, provides high voltage for field emission to the cathode and anode of the X-ray machine. Specifically, it includes a module for receiving high-voltage pulses output from the high-frequency high-voltage inverter and modulation module. The pulse interface and logic unit (PIL) for logic on / off control provides precise and fast-response gate voltage. Or extract pressure The gate / extraction electrode control circuit for the cold cathode, abbreviated as GDC / EDC, provides the DC bias potential of the cathode and the local feedback signal for stabilizing field emission. The cathode bias and stabilization circuit, abbreviated as CBS, is used to measure the cathode emission current. The emission current sampling circuit and the instructions from the main control and computing module control the gate / extractor drive circuit, and read the cathode emission current through the emission current sampling circuit. The microcontroller logic unit, abbreviated as μCL, is responsible for calculating launch stability indicators and communicating with the main control and computing modules in real time.

[0077] The working principle is briefly described as follows: High-voltage pulse application: The high-voltage pulse is applied... Safe and precise application to the cold cathode structure, typically with the cathode at a negative high voltage relative to the gate / anode. Gate / extraction electrode control: based on fine-tuning instructions from the MCC. Fine adjustment or This optimizes the electric field distribution and controls the emission current density and focal spot size. Emission current monitoring: High-precision, high-speed measurement of the cathode emission current for each pulse. Waveform, including amplitude, rise / fall time, and stability. Emission stability assessment: μCL real-time analysis of cathode emission current. If the waveform exceeds the system threshold, an alarm is set for the MCC. Rapid shutdown: The high-voltage pulse can be quickly cut off upon detecting unstable transmission or receiving a safety command. The path to the cathode or the clamping gate voltage. Precision Sensing & Acquisition Module (PSA), which will be abbreviated as PSA in the embodiments section, includes the anode high voltage... Drop to low pressure The high-voltage divider, emission current sensor, dose rate sensor interface, temperature sensor interface, high-speed analog-to-digital converter, and signal conditioning and isolation are included. This part of the embodiment utilizes existing technology and mainly performs signal conversion: converting various physical quantities (high voltage, current, dose rate, temperature) into analog electrical signals through sensors. Precision conditioning: amplifying, filtering, and linearizing weak or high common-mode signals to conform to the ADC input range. Electrical isolation: providing safe isolation between the high-voltage / power section and the low-voltage digital control section to prevent ground loop interference and high-voltage intrusion. High-speed synchronous acquisition: the ADC synchronously digitizes all sensor signals at a high sampling rate under precise clock control; data transmission: transmitting the digitized data stream to the MCC in real time through a high-speed interface.

[0078] The Safety Interlock & Status Monitoring Module (SISM) is a security logic controller connected to the precision sensing and acquisition module. It executes hard safety logic independent of the main control and computing modules based on the acquired information. Specifically, the safety logic controller includes a high-reliability PLC, a safety MCU, or dedicated safety relay logic, executing hard safety logic independent of the MCC.

[0079] Safety Input Interface: Connects to all safety-related sensors: door interlock switches, emergency stop buttons, vacuum sensor relay outputs, over-temperature sensors, dose accumulation over-limit signals, etc. Safety Output Interface: Drives safety relays, contactors, and audible / visual alarms. Hardware Watchdog: Monitors the operating status of the MCC and SLC; triggers reset or safety shutdown if no response is received within a timeout period. Health Monitoring Sensor Interface: Connects to vibration sensors, more precise temperature / humidity sensors, etc.

[0080] This part is merely a functional integration and does not involve any algorithmic innovation. Its working principle is not substantially different from existing technologies, so it will not be elaborated here.

[0081] The Human-Computer Interface & Communication Module (HCI) includes a main processor interface for connecting to the main control and computing module, a wireless communication unit, a display unit, an input unit, a cloud platform interface, and an audio output interface.

[0082] This part is also a functional integration, and does not involve any innovation in algorithms or structures. Its working principle is not substantially different from existing technologies, so it will not be elaborated here.

[0083] like Figures 2-7 As shown, the X-ray tube 1 includes a vacuum-equipped tube body and cold cathode and anode targets located at both ends inside the tube body. The tube body includes, from the inside out, an inner surface layer made of electropolished Kovar alloy, a ceramic-metal sealing layer, a ceramic insulating ring layer, a polyethylene layer, and a radiation shielding layer. A vacuum electric field acceleration cavity for electron acceleration is formed inside the inner surface layer.

[0084] Example 2:

[0085] This embodiment further optimizes the tube body based on the technology and figures of Embodiment 1. The inner surface layer is a 1mm thick Fe-Ni-Co alloy, with the specific ratio of the three metals being Fe 54%, Ni 29%, and Co 17%. Among them, the iron base metal provides the main structure and mechanical strength, while nickel and iron form a solid solution to reduce CTE through lattice distortion. Cobalt fine-tunes the lattice constant to compensate for the CTE mutation near the Curie point of the nickel-iron alloy, making the CTE curve linearized over a wide temperature range and optimizing the overall performance.

[0086] In terms of thermal expansion, the alloy with the above ratio does not exhibit drastic expansion abruptly near the Curie point, while maintaining a tensile strength of approximately 520 MPa to withstand the atmospheric pressure difference of the vacuum chamber; a yield strength of 345 MPa, which can effectively resist the stress of encapsulation, and can also achieve an elongation of 20%-30%, avoiding brittle fracture.

[0087] The ceramic-metal sealing layer is a metallized layer formed by sintering sequentially arranged molybdenum and manganese powders, with a thickness of 15-20 μm, the purpose of which is to form a solderable metal layer on the ceramic surface; the nickel-plated transition layer is used to improve the wettability of the solder, with a thickness of about 5-8 μm, and the gold-germanium eutectic brazing layer is used to improve the hermetic sealing capability, with a thickness that can be set to 30-50 μm; the ceramic insulating ring layer is a 2 mm thick 96% alumina ceramic with a withstand voltage strength >25 kV / mm and a vacuum leakage rate <10%. -14 mbar·L / s, tensile strength after metallization >80MPa; the external cooling layer is a composite structure of 316L stainless steel covering 0.8mm×1.2mm microchannels; the radiation shielding layer is an integral structure composed of tungsten-nickel alloy or lead particles.

[0088] Example 3:

[0089] This embodiment, based on embodiment 1 or embodiment 2, further optimizes the algorithm module in terms of control. Specifically, the control module 3 includes a main control and computing module (MCC) for receiving instructions from the human-machine interface and communication module (HCI) in real time, as well as receiving real-time data from the precision sensing and acquisition module (PSA) and the safety interlock and status monitoring module (SISM), and performing adaptive pulse parameter adjustments. , , The adaptive pulse parameters are calculated and dose management is performed. , , The algorithm used for the calculation is as follows:

[0090]

[0091] in, The pulse amplitude set voltage value calculated in the kth control cycle is represented by V; This represents the desired transmit current value. This represents the average emission current measured during the kth control cycle, in amperes (A). , Represents proportional and integral gain; ∑ represents the control cycle time, in seconds; ∑ represents the integral of the error from the start to the current cycle k.

[0092]

[0093]

[0094] in, The duration of a single high-voltage pulse, measured in microseconds (µs) or nanoseconds (ns). is the pulse width calibration coefficient, which is determined by the cathode characteristics; is the system reference resolution, is the actual required resolution, with the unit of LP / mm;

[0095] represents the repetition frequency of the pulse sequence, with the unit of Hz or kHz; is the frequency scaling factor, which is determined by the response speed of the high-voltage power supply, is the equivalent attenuation coefficient of the target material; is the equivalent attenuation coefficient of the detected material.

[0096] In this embodiment, the high-frequency high-voltage inversion and modulation module HFHI includes a digital controller for receiving instructions from the master control and calculation module and generating PWM / pulse control signals, a wide-bandgap semiconductor driver for providing isolation protection, a wide-bandgap semiconductor power stage module for core power conversion, a high-frequency power transformer for boosting with high frequency, high efficiency, and high insulation voltage, and a multi-stage sampling resonant network module for proportionally reducing the sampled anode high voltage to the low-voltage measurable range , and performing filtering processing; the multi-stage sampling resonant network module in the high-frequency high-voltage inversion and modulation module uses an LLC resonant converter to output voltage is calculated by the following formula:

[0097]

[0098] is the output DC bus voltage, is the input DC voltage, unit: V; N represents the transformer secondary / primary turn ratio; M is the voltage gain, related to the switching frequency; Q is the quality factor; ; is the normalized frequency, ; is the resonant frequency, .

[0099] In this embodiment, the LLC resonant converter used in the multi-stage sampling resonant network module is replaced with a PWM duty cycle control model, and the calculation method of the output voltage is as follows:

[0100]

[0101] Among them, is the topology factor, when the full-bridge structure , N is the transformer secondary / primary turn ratio; represents the PWM signal duty cycle and satisfies 0 < D < 1; the digital PI control algorithm is as follows:

[0102]

[0103] in, This represents the duty cycle setting for the k-th cycle; This is the anode voltage feedback in the kth cycle, in V. , These represent the voltage loop proportional gain and integral gain, respectively. Represents the control period, in seconds.

[0104] In this embodiment, the pulse drive and field emission control module (FDEC) includes a function for receiving high-voltage pulses output from the high-frequency high-voltage inverter and modulation module. It also includes a pulse interface and logic unit for logic on / off control, providing precise and fast-response gate voltage. Or extract pressure The gate / extraction electrode control circuit for the cold cathode provides the DC bias potential of the cathode and the local feedback signal for stabilizing field emission. The cathode bias and stabilization circuit is used to measure the cathode emission current. The emission current sampling circuit and the instructions from the main control and computing module control the gate / extraction electrode drive circuit, and read the cathode emission current. The microcontroller logic unit calculates the emission stability index and communicates with the main control and computing module in real time; the gate / extractor control circuit in the pulse drive and field emission control module 3 controls the field emission current density. J The equation is as follows:

[0105]

[0106] in, J Represents the emission current density, unit: A / m 2 A represents the effective emission area constant, in A·m. -2 ·V -2 ; The field enhancement factor is represented by E, which represents the applied electric field strength, in V / m.

[0107] Example 4:

[0108] This embodiment is based on any of the above embodiments, and in conjunction with the appendix. Figures 2-7As shown, in terms of structural optimization, the detection and control system provided in this embodiment also includes an X-ray machine for accommodating and fixing the X-ray tube 1 and the power module. The X-ray machine includes a cover 2 fixedly installed at both ends of the X-ray tube 1. The cover 2 is fixedly connected to the outer shell through a connector. The control module 3 is installed between the X-ray tube 1 and the outer shell. The power module includes a battery compartment 12. A battery socket 6 is provided in the battery compartment 12. Two contact pieces 7, which are electrically connected to the control module 3 and respectively electrically connected to the positive and negative terminals of the lithium battery 8, are fixedly installed in the battery socket 6.

[0109] To meet the complex environment of outdoor testing, both the adaptability of the equipment to outdoor environments and its portability must be considered. Preferably, the surface of the outer shell is also provided with an LCD screen 9 for display or manual touch input. The LCD screen 9 is electrically connected to the human-machine interface and communication module HCI. A protective film 11 is fixedly attached to the LCD screen 9. The outer shell is also provided with a patch antenna 10 that is electrically connected to the main control and computing module MCC for wireless data or signal transmission, and an interface 22 provided on the side wall or end face of the outer shell for connecting external transmission / power supply cables. A key switch 5 is provided between the control module 3 and the lithium battery 8.

[0110] In this embodiment, the outer shell includes a main shell 13 located in the middle and equipped with a handle, a first inner shell 16 and a second inner shell 18 respectively covered and spliced ​​to both ends of the main shell 13, and a first outer shell 17 and a second outer shell 19 respectively disposed outside the first inner shell 16 and the second inner shell 18 for protection and equipped with heat dissipation holes 23.

[0111] More preferably, the outer shell includes a side wall composed of a front shell 24, a left shell 25, a rear shell 26 and a right shell 27, and a top cover 28 and a bottom cover 29 detachably and fixedly connected to the side wall; a handle and a chassis support frame 14 for support are fixed or hinged on any side wall, and a plurality of buffer pads 15 are provided on the chassis support frame 14.

[0112] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art.

[0113] Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A cold cathode X-ray detection and control system, comprising an X-ray tube (1) having a cold cathode, a power supply module, and a control module (3) for modulating and boosting the power supply module and supplying excitation X-rays to the X-ray tube (1) for detection, characterized in that: The control module (3) includes a main control and computing module (MCC), which is bidirectionally connected to a high-frequency high-voltage inverter and modulation module (HFHI), a pulse drive and field emission control module (FDEC), a precision sensing and acquisition module (PSA), a safety interlock and status monitoring module (SISM), and a human-machine interface and communication module (HCI) via a high-speed digital control bus. The high-voltage pulse output of the high-frequency high-voltage inverter and modulation module (HFHI) is... The input terminal of the pulse drive and field emission control module (3) FDEC is connected, and the output terminal of the pulse drive and field emission control module (3) FDEC is connected to the cold cathode; the precision sensing and acquisition module PSA is connected to a voltage sensor, a current sensor, a dose rate sensor and a temperature sensor through a precision analog front-end circuit AFE; the safety interlock and status monitoring module SISM is connected to a door switch, an emergency stop button, a vacuum gauge relay, an audible and visual alarm and a safety relay through digital I / O or simple analog; The ray tube (1) includes a vacuum-set tube body and cold cathode and anode targets located at both ends inside the tube body. The tube body includes, from the inside out, an inner surface layer made of electropolished Kovar alloy, a ceramic-metal sealing layer, a ceramic insulating ring layer, a polyethylene layer and a radiation shielding layer. The inner surface layer forms a vacuum electric field acceleration cavity for electron acceleration.

2. The cold cathode ray detection and control system according to claim 1, characterized in that: The inner surface layer is a 1mm thick Fe-Ni-Co alloy; the ceramic-metal sealing layer consists of a metallized layer formed by sintering molybdenum-manganese powder, a nickel-plated transition layer, and a gold-germanium eutectic brazing layer arranged sequentially; the ceramic insulating ring layer is a 2mm thick 96% alumina ceramic, and the outer cooling layer is a composite structure of 0.8mm×1.2mm microchannels covered by 316L stainless steel; the radiation shielding layer is an integral structure composed of tungsten-nickel alloy or lead particles.

3. The cold cathode ray detection and control system according to claim 1, characterized in that: The control module (3) includes a main control and computing module (MCC) for receiving instructions from the human-machine interface and communication module (HCI) in real time, as well as receiving real-time data from the precision sensing and acquisition module (PSA) and the safety interlock and status monitoring module (SISM), and performing adaptive pulse parameter calculations. , , The adaptive pulse parameters are calculated and dose management is performed. , , The algorithm used for the calculation is as follows: ; in, The pulse amplitude set voltage value calculated in the kth control cycle is represented by V; This represents the desired transmit current value. This represents the average emission current measured during the kth control cycle, in amperes (A). , Represents proportional and integral gain; ∑ represents the control cycle time, in seconds; ∑ represents the integral of the error from the start to the current cycle k. ; ; in, The duration of a single high-voltage pulse, measured in microseconds (µs) or nanoseconds (ns). It is the pulse width calibration coefficient, which is determined by the cathode characteristics; It is the system's baseline resolution. This refers to the actual required resolution, expressed in LP / mm. Represents the repetition frequency of a pulse sequence, measured in Hz or kHz; It is a frequency scaling factor, determined by the response speed of the high-voltage power supply. It is the equivalent attenuation coefficient of the target material; It is the equivalent attenuation coefficient of the tested material.

4. The cold cathode ray detection and control system according to claim 1, characterized in that: The high-frequency high-voltage inverter and modulation module HFHI includes a digital controller for receiving instructions from the main control and computing module and generating PWM / pulse control signals, a wide-bandgap semiconductor driver providing isolation protection, a wide-bandgap semiconductor power stage module for core power conversion, a high-frequency power transformer for boosting high-frequency, high-efficiency, and high-insulation-voltage signals, and a module for sampling the anode high voltage. Reduced proportionally to the low-pressure measurable range The multi-stage sampling resonant network module performs filtering; the multi-stage sampling resonant network module in the high-frequency high-voltage inverter and modulation module uses the output voltage of an LLC resonant converter. It is obtained by calculation using the following formula: ; It is the output DC bus voltage. It is the input DC voltage, in volts (V). N represents the secondary to primary turns ratio of the transformer; M is the voltage gain, which is related to the switching frequency; Q is the quality factor. ; It is the normalized frequency. ; It is the resonant frequency. .

5. A cold cathode ray detection and control system according to claim 4, characterized in that: The LLC resonant converter used in the multi-stage sampling resonant network module is replaced with a PWM duty cycle control model, and the output voltage is... The calculation method is as follows: ; in, As the topology factor, in a full-bridge structure N is the secondary / primary turns ratio of the transformer; The signal represents the duty cycle of the PWM signal and satisfies 0 < D < 1; the digital PI control algorithm is as follows: ; in, This represents the duty cycle setting for the k-th cycle; This is the anode voltage feedback in the kth cycle, in V. , These represent the voltage loop proportional gain and integral gain, respectively. Represents the control period, in seconds.

6. A cold cathode ray detection and control system according to claim 1, characterized in that: The pulse drive and field emission control module (3) FDEC includes a high-voltage pulse receiver for receiving the output of the high-frequency high-voltage inverter and modulation module. It also includes a pulse interface and logic unit for logic on / off control, providing precise and fast-response gate voltage. Or extract pressure The gate / extraction electrode control circuit for the cold cathode provides the DC bias potential of the cathode and the local feedback signal for stabilizing field emission. The cathode bias and stabilization circuit is used to measure the cathode emission current. The emission current sampling circuit and the instructions from the main control and computing module control the gate / extraction electrode drive circuit, and read the cathode emission current. The microcontroller logic unit calculates the emission stability index and communicates with the main control and calculation module in real time; the equation for the gate / extractor control circuit in the pulse drive and field emission control module (3) to control the field emission current density J is as follows: Where J represents the emission current density, in A / m³. 2 A represents the effective emission area constant, in A·m. -2 ·V -2 ; The field enhancement factor is represented by E, which represents the applied electric field strength, in V / m.

7. A cold cathode ray detection and control system according to claim 1, characterized in that: It also includes a ray machine for accommodating and fixing the ray tube (1) and the power module. The ray machine includes a cover (2) fixedly installed at both ends of the ray tube (1). The cover (2) is fixedly connected to the outer shell by a connector. The control module (3) is installed between the ray tube (1) and the outer shell. The power module includes a battery compartment (12). A battery socket (6) is provided in the battery compartment (12). Two contact pieces (7) that are electrically connected to the control module (3) and respectively electrically connected to the positive and negative terminals of the lithium battery (8) are fixedly provided in the battery socket (6).

8. A cold cathode ray detection and control system according to claim 7, characterized in that: The outer casing is also provided with an LCD screen (9) for display or manual touch input. The LCD screen (9) is electrically connected to the human-machine interface and communication module HCI. A protective film (11) is fixedly pasted on the LCD screen (9). The outer casing is also provided with a patch antenna (10) electrically connected to the main control and computing module MCC for wireless data or signal transmission, and an interface (22) provided on the side wall or end face of the outer casing for external transmission / power supply cables. A key switch (5) is provided between the control module (3) and the lithium battery (8).

9. A cold cathode ray detection and control system according to claim 7, characterized in that: The outer shell includes a main shell (13) located in the middle and equipped with a handle, a first inner shell (16) and a second inner shell (18) respectively covered and spliced ​​to both ends of the main shell (13), and a first outer shell (17) and a second outer shell (19) respectively disposed outside the first inner shell (16) and the second inner shell (18) for protection and equipped with heat dissipation holes (23).

10. A cold cathode ray detection and control system according to claim 7, characterized in that: The outer shell includes a side wall consisting of a front shell (24), a left shell (25), a rear shell (26) and a right shell (27), and a top cover (28) and a bottom cover (29) that are detachably and fixedly connected to the side wall; a handle and a chassis support frame (14) for support are fixed or hinged on any side wall, and a plurality of buffer pads (15) are provided on the chassis support frame (14).

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