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High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 1 (2024)
[in Chinese]
Study on high-power S-band frequency-controlled microwave source based on injection locking
Zhenlong Liu
The high-power microwave source does not satisfy the requirements for deep space communications, wireless power transmission systems and high-power superconducting accelerators because of the real-time power control problems. To break through such limitations, an available power control method based on injection lockinThe high-power microwave source does not satisfy the requirements for deep space communications, wireless power transmission systems and high-power superconducting accelerators because of the real-time power control problems. To break through such limitations, an available power control method based on injection locking is proposed. Theoretical analysis and experiment are carried out to prove the performance of the proposed frequency-controlled microwave source based on dual 20 kW S-band high power magnetrons. The experiment results show that the real-time power control combining via the injecting frequency is achieved, when the injection power or free-running frequency of magnetron is unequal. Simultaneously, the system shows an output power control range of 3.0 dB, a nearly 4.0 MHz injection-locking bandwidth, and a sharp spectrum with an excellent spur suppression ratio of -65.0 dBc@500 kHz. The highest combining power output of 33.9 kW with the system efficiency of 86.6% is also proved. Such researches play an important role in the development of high-power microwave applications..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 093001 (2024)
Design of V-band coaxial transit time oscillator with TM03 mode
Fanbo Zeng, Jiande Zhang, Juntao He, and Junpu Ling
Increasing frequency is always an important development direction of high power microwave (HPM). However, as the frequency increases, the volume of an HPM device decreases rapidly and so does the power handling capacity (PHC). For obtaining reasonable PHC, the design of a V-band coaxial transit time oscillator (TTO) baIncreasing frequency is always an important development direction of high power microwave (HPM). However, as the frequency increases, the volume of an HPM device decreases rapidly and so does the power handling capacity (PHC). For obtaining reasonable PHC, the design of a V-band coaxial transit time oscillator (TTO) based on TM03 mode is carried out to achieve low surface field in this paper. The slow wave structure (SWS) having a large radial width with TM03 mode in such a device designed will lead to low risk of both electric field breakdown and pulse shortening. Firstly, the synchronous effect of velocity between microwave and electron beam is achieved by calculation of dispersion curve and coupling impedance. Then, small group velocity and high coupling impedance are designed to make TM03 a dominant mode in the coaxial V-band TTO. Finally, under the condition of 440 kV and 5 kA, an HPM is generated to reach an output power of 440 MW with a low surface electric field of 1.6 MV/cm, a microwave frequency of 62.25 GHz, and a beam-to-wave efficiency of 22% from numerical simulation..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 093002 (2024)
Analysis of the influence of key parameters of step-frequency radar on false alarm signal
Xue Du, Guanghui Wei, and Dalin Wu
Aiming at the problem of multiple false alarm signals of radar equipment in complex electromagnetic interference, in order to get the influence law of key parameters of radar equipment on false alarm signals, and to reveal the essential causes of false alarm signals, taking a type of stepper frequency ranging radar as Aiming at the problem of multiple false alarm signals of radar equipment in complex electromagnetic interference, in order to get the influence law of key parameters of radar equipment on false alarm signals, and to reveal the essential causes of false alarm signals, taking a type of stepper frequency ranging radar as the test object, this paper theoretically explains the mechanism of false alarm interference and the imaging characteristics of false alarm targets. Combining theoretical and experimental measurements, single-frequency continuous wave is selected as the source of electromagnetic interference, and the test method of injecting equivalent alternative electromagnetic radiation is adopted to summarize and generalize the influence of the critical radar parameters including frequency hopping interval and stepping frequency on the false alarm signal. The results show that the single-frequency electromagnetic interference of the test radar generates false alarm signal. When the frequency stepping of the tested radar is selected as 10 kHz and the frequency hopping time is 0.05 ms, the variation of false alarm level with interference frequency offset is relatively stable, and the signal amplitude loss is relatively small. The values can be used as the optimal control parameter values, and on this basis, it can provide technical support for subsequent experimental evaluation of radar equipment in multi frequency electromagnetic environments..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 093003 (2024)
Design of common aperture multi-beam shaped reflector antenna for satellite communications
Xiaofeng Yang, Chengkun Yang, and Qinggong Guo
To meet the requirement of multiple tasks in parallel in spaceborne communication, this paper proposes a common aperture multi-beam reflector antenna composed of a Gregorian reflector and three feed-horn antennas, which can generate two contoured beams and one spot beam. The antenna is designed using ray tracing methodTo meet the requirement of multiple tasks in parallel in spaceborne communication, this paper proposes a common aperture multi-beam reflector antenna composed of a Gregorian reflector and three feed-horn antennas, which can generate two contoured beams and one spot beam. The antenna is designed using ray tracing method to determine the optimal spot beam feed position for establishing the antenna infrastructure, and employing Zernike polynomials and cubic B-splines function to optimize the shape of both the main and secondary reflectors. To validate the efficacy of the method, simulation experiments were conducted on 1.1 m diameter antenna. The results demonstrate that the edge of coverage gain for both shaped contour beams in Ku receiving and transmitting bands are 27.7 dBi, 28.0 dBi, 28.0 dBi and 28.2 dBi, respectively. The spot beam exhibits a minimum service EOC gain of not less than 34 dBi, while the scanning beam gain within the range of 0 to 6.5° is not less than 35 dBi..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 093004 (2024)
[in Chinese]
Focal spot measurement technology of multi-beam laser bunching
Zhihong Sun, Bo Zhang, Junpu Zhao, Jun Dong, Fa Zeng, and Ping Li
To realize multi-channel laser cluster focal spot measurement and give its temporal and spatial resolution characteristics, a focal spot optical measurement platform based on imaging system, photodiode combined with oscilloscope, streak camera and scientific CCD is built. Before the experiment, the sensitivity and dynaTo realize multi-channel laser cluster focal spot measurement and give its temporal and spatial resolution characteristics, a focal spot optical measurement platform based on imaging system, photodiode combined with oscilloscope, streak camera and scientific CCD is built. Before the experiment, the sensitivity and dynamic range of the scientific CCD and the performance parameters of the streak camera, such as gain coefficient, slit width and scanning time, were tested and calibrated off-line. The CCD is used to measure the spatial distribution of multi-channel laser cluster focal spot with time integration. By using photodiode combined with oscilloscope and streak camera, the time synchronization of multi-channel laser reaching the target is tested. The time-resolved characteristics of high-quality cluster focal spot are measured, and the fine spatio-temporal evolution image of spectral dispersion smooth beam focal spot is obtained. The test of focal spot shape and time synchronization of multi-beam channel laser cluster provide support for improving focal spot test technology and method of high-power laser device..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 092001 (2024)
[in Chinese]
Quantification of calculated effective multiplication factor uncertainty caused by nuclear data in research reactor
Jingyu Sun, and Jimin Ma
To delve into the impact of nuclear data uncertainty on the effective multiplication factor calculation for the JRR-3M research reactor, this study established a nuclear data uncertainty quantification process based on SANDY. The specific methodology involved perturbing important reaction pathways of the target nuclideTo delve into the impact of nuclear data uncertainty on the effective multiplication factor calculation for the JRR-3M research reactor, this study established a nuclear data uncertainty quantification process based on SANDY. The specific methodology involved perturbing important reaction pathways of the target nuclides with SANDY to generate perturbation files, processing these files with NJOY, and ultimately utilizing OpenMC for Monte Carlo simulations. The influence on the effective multiplication factor due to several key nuclides (such as 235U, 238U, Hf, etc.) data uncertainty was calculated and analysed for three operational conditions of the JRR-3M research reactor. For critical, control rods fully inserted and control rods fully withdrawn conditions, total effective multiplication factor uncertainties are 660.8×10-5, 588.5×10-5 and 708.4×10-5, respectively. In all operational conditions, the impact of the fission release neutron energy distribution of 235U is the most notable. The study reveals that within hafnium control rods only the nuclear data uncertainty of 177Hf plays a major role..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 096001 (2024)
Development and tests of functions of proton, low-energy photon and electron transport in JMCT3.0 Monte Carlo particle transport program
Xiao Tan, Li Deng, Lingyu Zhang, Rui Li, Yuanguang Fu, Dunfu Shi, Peng Liu, and Chao Yang
The Monte Carlo code JMCT can simulate neutron/photon/electron/proton/molecule/light radiation/atmosphere transport problems in any complicated geometry system. It supports the multi-level parallelization in scale of over one hundred thousand cores. At present, JMCT has been widely applied in radiation shielding, critiThe Monte Carlo code JMCT can simulate neutron/photon/electron/proton/molecule/light radiation/atmosphere transport problems in any complicated geometry system. It supports the multi-level parallelization in scale of over one hundred thousand cores. At present, JMCT has been widely applied in radiation shielding, critical safety analysis of reactor, nuclear detection and nuclear medicine etc. JMCT3.0 is a large-scale, high-fidelity, three-dimensional general multi-particle transport Monte Carlo (MC) program, and thirteen new functions and eight new algorithms have been developed based on JMCT2.0. The computing efficiency is enhanced 30%-600% by optimizing of JCOGIN infrastructure. This paper introduces the methods and new functions of proton, low-energy photon/ electron/molecule transport in JMCT3.0. The validity of algorithms has been proved by benchmarks. The new functions are mainly used for simulations of image diagnosis, flash radiography, light radiation and atmosphere transport..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 096002 (2024)
Study on electromagnetic sensitivity of power modules of high-speed comparator and clock driver
Ning Li, Zhigang Peng, and Chaohui He
High altitude electromagnetic pulse (HEMP) can produce electromagnetic pulse effects on electronic devices or systems that cannot be ignored. In this paper, a high-speed comparator and a clock driver are selected, and the electromagnetic sensitivity of the power modules of these two devices is studied by the experimentHigh altitude electromagnetic pulse (HEMP) can produce electromagnetic pulse effects on electronic devices or systems that cannot be ignored. In this paper, a high-speed comparator and a clock driver are selected, and the electromagnetic sensitivity of the power modules of these two devices is studied by the experimental method of pulse current injection (PCI). The test results show that the rising edge of the double exponential pulse current is the main cause of the output glitch of the high-speed comparator and clock driver, and the amplitude of the disturbance is affected by the amplitude of the injected pulse current. The electromagnetic sensitivity of the power module of the high-speed comparator is different at different output level. Different operating frequencies of high-speed comparators and clock drivers will show different electromagnetic sensitivity. The results have certain guiding significance for electromagnetic sensitivity analysis and hardening of electronic devices or systems..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 096003 (2024)
Coded-aperture image reconstruction algorithm based on maximum a posteriori estimation
Yurui Qin, Balin Zhu, Zhonghai Wang, Rong Zhou, and Chaowen Yang
Image reconstruction algorithms significantly influence the imaging performance of coded-aperture gamma cameras. However, the widely used Maximum Likelihood Expectation Maximization (MLEM) algorithm falls short in effectively suppressing noise amidst stronger background interference because it relies on the system respImage reconstruction algorithms significantly influence the imaging performance of coded-aperture gamma cameras. However, the widely used Maximum Likelihood Expectation Maximization (MLEM) algorithm falls short in effectively suppressing noise amidst stronger background interference because it relies on the system response matrix under ideal conditions. This paper presents corresponding research and improvements regarding the “pathological” nature of the MLEM algorithm. Firstly, the maximum a posteriori (MAP) algorithm was applied to the image reconstruction of coded aperture imaging, followed by an analysis of the selection methods for key parameters such as the neighborhood size and weight coefficient within the Gibbs prior function of the algorithm. Then, we conducted imaging experiments using the prototype of the coded-aperture gamma camera and compared the image reconstruction results of the MLEM algorithm and the MAP algorithm for the 22Na point source. In the range of 300 to 1200 iterations, the MLEM reconstructed images exhibited noticeable noise spots, with image quality progressively deteriorating as the iterations deepened. In contrast, the MAP reconstructed images did not present any significant noise spots. The average gradient of the reconstructed images was reduced by 26.45% to 49.16% compared to MLEM, and the contrast-to-noise ratio (CNR) was improved by 42.32% to 351.07%. Furthermore, we compared the reconstruction results of multi-point source images with 3 × 3 and 5 × 5 neighborhood sizes. The results indicate that smaller neighborhood size leads to a decrease in the brightness of the hotspots in the reconstructed images, consistent with the theoretical analysis. Finally, we compared the imaging results of the MLEM and MAP algorithms in two separate scenarios: one with greater distance and the other with stronger interference. In both scenarios, the MAP algorithm demonstrated better signal-to-noise ratio (SNR) performance..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 096004 (2024)
[in Chinese]
Three-dimensional coordinate calibration technology for high energy photon source magnets
Yuanying Han, Lan Dong, Tong Wang, Shang Lu, Luping Yan, Luyan Zhang, Xiaoyang Liu, Haoyue Yan, Lingling Men, Xiaolong Wang, Bo Li, Jing Liang, Na Ma, Zhenqiang He, and Zhiyong Ke
Aiming at the High Energy Photon Source which needs to calibrate the center of a large number of magnets, a scheme of calibrating the center of magnetic machinery based on coordinate measuring machine (CMM) is proposed, the process and method of writing automatic measuring program are determined, and the calibration ofAiming at the High Energy Photon Source which needs to calibrate the center of a large number of magnets, a scheme of calibrating the center of magnetic machinery based on coordinate measuring machine (CMM) is proposed, the process and method of writing automatic measuring program are determined, and the calibration of various types of magnets in the accelerator is completed. The results show that the calibration repeatability of the reference point of collimation is within 0.01 mm by calibrating the mechanical center twice for each magnet. The standard deviation between the measured value and the design value is within 0.015 mm. The calibration efficiency is 2 times higher than that of the laser tracker. This method of magnet calibration with CMM can improve the calibration accuracy, reduce the labor cost, improve the work efficiency, provide reference for the magnet center extraction calibration in the accelerator work, ensure the smooth installation of the accelerator device, and meet the requirements of the accelerator alignment measurement project schedule..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 094001 (2024)
Diagnosis and simulation of Penning source in associated neutron tube
Longjian Ye, Pan Dong, Jie Li, Dongdong Zhang, Yuhang Chen, and Zhijie Hu
Penning ion source has been widely used in associated neutron tube due to its simple structure, small size and low power consumption. Based on the Penning ion source used in the laboratory, the volt-ampere characteristics in the ionization process are analyzed. The distribution of plasma is observed by a CCD camera insPenning ion source has been widely used in associated neutron tube due to its simple structure, small size and low power consumption. Based on the Penning ion source used in the laboratory, the volt-ampere characteristics in the ionization process are analyzed. The distribution of plasma is observed by a CCD camera inside the ion source. The density and temperature of electrons are analyzed by spectroscopy of the hydrogen plasma. Based on the Penning ion source structure used in the laboratory, this paper establishes a global model of collision ionization of H2 molecules and analyzes the influence of working parameters of ion source to the electron temperature and electron density in the plasma. The electron density increases gradually with the increase of discharge power, and it increases first and then decreases when the magnetic field and pressure increase. It is necessary to control the magnetic field within 0.03-0.05 T, and the pressure within (0.2-2)×10-2 Pa. The electron temperature increases with the power and decreases with pressure. The model shows that the electron temperature is less than 10 eV, and the electron density is 1010 cm-3 in the operating range of Penning ion source..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 094002 (2024)
Design of solenoid snake for Super Tau-Charm Facility based on particle swarm optimization algorithm
Jieqin Lan, Minliang Zhong, Dongliang Wang, Weihuang Li, Gan Tan, Derong Zeng, and Weiwei Gao
Installing an odd number of Siberian snakes at equal azimuth intervals in a circular collider is a common scheme for obtaining longitudinally polarized beam collisions. In this paper, the solenoid Siberian snake is selected as the device to preserve beam polarization in the Super Tau-Charm Facility according to its chaInstalling an odd number of Siberian snakes at equal azimuth intervals in a circular collider is a common scheme for obtaining longitudinally polarized beam collisions. In this paper, the solenoid Siberian snake is selected as the device to preserve beam polarization in the Super Tau-Charm Facility according to its characteristics. The paper introduces in detail how to combine particle swarm optimization algorithm with decoupling and optical matching problem of solenoid snake to design it quickly and optimally, and presents the design results. The results show that the optimization design of solenoid snake based on particle swarm optimization algorithm is effective and efficient..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 094003 (2024)
High throughput of cell irradiation with microfluidics in single ion microbeam system
Furu Zhan
The irradiation throughout means the amount of the cells irradiated per unit time, which is the important performance indicator of a single ion microbeam system. To improve the single ion localization irradiation throughout, microfluidic chip technology is applied to the single ion beam cell irradiation system with sinThe irradiation throughout means the amount of the cells irradiated per unit time, which is the important performance indicator of a single ion microbeam system. To improve the single ion localization irradiation throughout, microfluidic chip technology is applied to the single ion beam cell irradiation system with single ion to single cell auto-irradiation. A cell storage pool, O2 and CO2 injection channels, constant temperature control, pH detection and cell inspection are built on the chip. Ions irradiate the moving cells through the irradiation point on the microfluidic chip. Based CAS-LIBB system, this article establishes a computational model for ion targeting microfluidic cells. The basic methods and laws of ion targeting microfluidic cells are studied, therefore it has obtained the multi-relationships among cell velocity, irradiation throughout, irradiation dose, and cell separation, which are the theoretical guidance for system operation. A mode of “Promptly Irradiate with Inspected” is proposed to improve the irradiating effectivity and accuracy. The results show that there is an upper limit for cell speed as well as for irradiation throughout, and increasing cell number density and ion emission density are the most feasible ways to raise the irradiation throughout. With the microfluidic technology, the irradiation throughout now reaches 10000 cells/h, more than 10 times higher than before. The calculated data is basically consistent with the experimental results..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 094004 (2024)
[in Chinese]
Technology and application of the voltage-controlled pulse power semiconductor devices
Ruize Sun, Wanjun Chen, Chao Liu, Honghua Liu, Hongmei Yao, and Bo Zhang
Pulse power technology compresses low-power energy in the time domain to achieve high-power output in extremely short durations. In recent years, the trend in pulse power technology has been replacing traditional gas or vacuum switches with a new generation of semiconductor switches. To promote the technical developmenPulse power technology compresses low-power energy in the time domain to achieve high-power output in extremely short durations. In recent years, the trend in pulse power technology has been replacing traditional gas or vacuum switches with a new generation of semiconductor switches. To promote the technical development in the field of pulse power semiconductor devices, this article briefly introduces the development history of voltage-controlled pulse power semiconductor devices and the structure of MOS-controlled thyristors (MCTs). By comparing the pulse performance of MCT with that of commercial IGBT, it illustrates the advantages of high pulse current peak and high di/dt pulse of MCT under the same conditions. However, the conventional MCT cannot be turned off at zero gate voltage, and the carrier injection efficiency and conduction speed need to be further improved. To solve the shortcomings of conventional MCT that can not be turned off under zero voltage, this article then summarizes the research progress in device design, technology, and reliability of MCT. It also demonstrates the advantages of MCT devices in typical application scenarios and provides a brief analysis of the development trends of voltage-controlled pulse power semiconductor devices..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 095001 (2024)
Circuit topology optimization and performance improvement of magnetic resistance coil launcher
Zhenchun Wang, Yan Hu, and Yuting Zhang
To improve the muzzle speed and energy utilization of the coil launcher, this article studies the impact of different circuit topology structures of the magnetic resistance electromagnetic coil launcher to improve the performance. Four topology structures, including silicon controlled rectifier (SCR) type, half-bridge To improve the muzzle speed and energy utilization of the coil launcher, this article studies the impact of different circuit topology structures of the magnetic resistance electromagnetic coil launcher to improve the performance. Four topology structures, including silicon controlled rectifier (SCR) type, half-bridge type, resistor capacitor diode (RCD) absorption type, and boost-buck type, are analyzed, and the influence of different topology on the performance is studied by finite element method. The results show that under the same conditions, compared with the SCR circuit, among the three switchable circuits, the boost-buck circuit has the least increase in armature muzzle speed, which is 78.77%; the RCD circuit has the least increase in system energy utilization, which is 220.66%. The attenuation rate of the current in the turn-off circuit will affect the acceleration of the armature, and there is an optimal current attenuation rate curve. The one with the most balanced combination of muzzle speed and system energy utilization in the single-stage turn-off circuits is the half-bridge discharge circuit; boost-buck discharge circuit is more flexible and suitable for use in multi-stage coil launcher..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 095002 (2024)
Development of a MV level peaking capacitor integrated capacitor voltage divider
Qisheng Li, Junna Li, Chu’nan Li, Yongliang Wang, Yuhan Gong, and Jian Liu
Peaking capacitors, due to their compact structure, generally use indirect measurement of the voltage they bear, and direct measurement of their voltage has always been a difficult problem to solve. To solve this problem, we developed a new type of resistance compensation type self-integrating peak capacitor integratedPeaking capacitors, due to their compact structure, generally use indirect measurement of the voltage they bear, and direct measurement of their voltage has always been a difficult problem to solve. To solve this problem, we developed a new type of resistance compensation type self-integrating peak capacitor integrated capacitor voltage divider based on peaking capacitors. Secondly, based on the new structure of the voltage divider, the theoretical voltage ratio of the peak capacitance integrated capacitor voltage divider was analyzed. The calculation formula for the theoretical voltage ratio and the analysis of factors affecting low-frequency response were provided, and circuit simulation verification was carried out. At the same time, square wave calibration experiments were conducted, and the partial pressure ratio and response time of the two probes were obtained, and the response time of the probes was less than 6.2 ns. In addition, to obtain a more accurate voltage ratio and verify the stability of the voltage ratio of the integrated capacitor voltage divider under normal working conditions, high-voltage online calibration experiments were conducted, and the voltage ratio of probe 1 was 11071 and probe 2 was 15148 . Moreover, at higher voltage levels, the relative measurement error of the capacitive voltage divider probe is relatively small, and the voltage divider ratio has good stability..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 095003 (2024)
[in Chinese]
Predictive modeling of the surface pattern of double-sided polishing process of optical components
Zhikai Mi, Fengming Nie, Siling Huang, and Feng Xue
To address the challenge of establishing a stable removal function for double-sided polishing to predict the finished surface profile, we use the coordinate transformation method to derive the relative velocity distribution equations for the upper and lower surfaces of the component. Subsequently, static pressure distrTo address the challenge of establishing a stable removal function for double-sided polishing to predict the finished surface profile, we use the coordinate transformation method to derive the relative velocity distribution equations for the upper and lower surfaces of the component. Subsequently, static pressure distributions on both surfaces are simulated using ANSYS software. The simulation data is then imported into Matlab and fitted with a polynomial method to determine the time-varying pressure distribution formulas for the component's surfaces. Based on the Preston equation, an expression for the correction coefficient K is derived. The value of the correction coefficient K is calculated to be 2.588×10-15 from four sets of polishing experimental data, enabling the construction of a predictive model for the surface pattern in double-sided polishing processes. The predictive model is ultimately validated through machining experiments. The experimental results indicate that the error in predicting the PV (Peak-to-Valley) value accounts for 1.07% to 7.4% of the actual PV value after processing, demonstrating good agreement between the predicted model and the actual post-processing surface pattern..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 091001 (2024)
Spectral intensity and stability of surface-enhanced laser-induced breakdown spectroscopy of metallic microstructure
Yanbing Qi, Jiayuan Tang, Meng’en Jiang, and Weidong Zhou
To enhance the performance of laser-induced breakdown spectroscopy (LIBS) for the analysis of element Cr in solutions, a surface-enhanced LIBS technique combining metallic microstructures is proposed. Initially, using femtosecond laser surface texturing technology, various shapes and cycles of microstructures includingTo enhance the performance of laser-induced breakdown spectroscopy (LIBS) for the analysis of element Cr in solutions, a surface-enhanced LIBS technique combining metallic microstructures is proposed. Initially, using femtosecond laser surface texturing technology, various shapes and cycles of microstructures including rectangles, circles, triangles, and hexagons were etched on the surface of metallic aluminum. Through comparative analysis, the effects of different microstructures on the surface-enhanced LIBS spectral intensity and stability of Cr-element aqueous solutions deposited on them were investigated. The results indicate that smaller microstructure cycles result in more significant spectral enhancement, with rectangular microstructures demonstrating the optimal spectral enhancement at the same period, increasing the spectral intensity by approximately four times compared to untreated metallic aluminum. Furthermore, hexagonal microstructures exhibit the best spectral stability and repeatability. These findings provide a viable method for substrate preparation for applying surface-enhanced LIBS techniques to the detection of heavy metal elements in aqueous solutions..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 091002 (2024)
Three-dimensional reconstruction system for transparent samples based on phase retrieval
Haoyue Cao, Chen Zhao, Jing Liu, He Peng, Yang Zhou, Shuwei Yang, Yue Ma, and Yibing Lu
In response to the difficulties posed by traditional microscopy imaging techniques in capturing the structure and thickness of colorless transparent samples, we have designed a miniature three-dimensional reconstruction system for such samples. This innovative system, breaking away from traditional optical structures, In response to the difficulties posed by traditional microscopy imaging techniques in capturing the structure and thickness of colorless transparent samples, we have designed a miniature three-dimensional reconstruction system for such samples. This innovative system, breaking away from traditional optical structures, performs phase retrieval on transparent samples to achieve three-dimensional reconstruction. It requires only light carrying sample information, which is then bifurcated by a spectroscope and captured by a stereo camera. Constructed using 3D printing technology, the compact system measures just 110 mm×110 mm×60 mm, offering a cost-effective solution that is also compatible with traditional microscopy imaging equipment. It incorporates autofocus and field of view correction algorithms, which, by collecting one over-focused and one under-focused image, solve the transport intensity equation to enable phase retrieval and hence the three-dimensional reconstruction of transparent samples. Test results have shown that the system can achieve an imaging resolution of 2.46 μm under a 10× objective lens, and the phase recovery accuracy can also meet the basic requirements. Furthermore, the successful three-dimensional reconstruction of blood cells and scratches on microscope slides validates the system's feasibility and practicality..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 091003 (2024)
Advanced Interdisciplinary Science
Parameter estimation method for frequency hopping signal based on time-frequency transform and waveform shaping
Chuanchuan Wang, Kuanqiao Zhang, and Manxi Wang
In view of the adverse effect of noise on frequency hopping signal parameter estimation, a frequency hopping signal parameter estimation method based on time-frequency transform and waveform shaping is proposed. The time-frequency ridge is calculated by the short-time Fourier transform of the frequency hopping signal, In view of the adverse effect of noise on frequency hopping signal parameter estimation, a frequency hopping signal parameter estimation method based on time-frequency transform and waveform shaping is proposed. The time-frequency ridge is calculated by the short-time Fourier transform of the frequency hopping signal, the waveform shaping of the time-frequency ridge is processed to eliminate the false time-hopping interference caused by noise, and the hopping period sequence is obtained through the time-hopping sequence. The histogram of the hopping period sequence is calculated, and the value with the most occurrence times is selected to calculate the hopping speed of the frequency hopping signal. According to the hopping period sequence, signal of each hop is extracted respectively, and then the frequency is estimated. The effectiveness of the proposed method is verified by experiments, and the ideal estimation results of hopping time, hopping speed and frequency of frequency hopping signal under low signal-to-noise ratio are guaranteed by comprehensive use of time-frequency transformation and waveform shaping technology..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 099001 (2024)
Prediction of system-level electric field radiated emission based on ANN reverse model
Luyao Liu, Xiao Jin, and Jinliang Cai
To address the issue of system-level electromagnetic compatibility, a new method of predicting electromagnetic interference of complex systems based on artificial neural network (ANN) reverse model is proposed in this paper. Firstly, the electric field radiated emission (RE) of single equipment is measured. The traininTo address the issue of system-level electromagnetic compatibility, a new method of predicting electromagnetic interference of complex systems based on artificial neural network (ANN) reverse model is proposed in this paper. Firstly, the electric field radiated emission (RE) of single equipment is measured. The training data of system-level RE are obtained by simulation based on the equivalence principle of radiated emission. Frequency, RE and coordinate of each single equipment are selected as the input variables, and the system-level RE is the output variable. A reverse model of the three-layer back-propagation (BP) ANN with Levenberg-Marquardt (LM) algorithm is established by exchanging the input–output variables. The alternative ANN with minimum validation error is searched as the ultimate ANN. The numerical root-finding algorithm (regular-falsi method and conjugate gradient method) are adopted to calculate the RE of multi equipments. The results show that the validation error of this reverse model is significantly improved compared to the traditional three-layer LM-BP ANN. Especially, the ANN reverse model based on conjugate gradient method reduces the validation error from 0.4159 % to 0.0997 %. This method is independent of complex ANN structures, and improves simulation accuracy with limited training data, which provides a new efficient and feasible solution for electromagnetic compatibility evaluation of electronic information platforms such as ships, satellites, and aircrafts..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 099002 (2024)
Special Column of 4Th Symposium on Frontier of HPLPB
Nernst effects study using dopant layer on magnetized target
Shijia Chen, Hua Zhang, Cangtao Zhou, Hongbin Zhuo, Fuyuan Wu, and Ramis Rafael
The two-layer magnetized liner target offers an alternative approach to magnetized target fusion implosions by incorporating high atomic number (Z) materials in the innermost layer to mitigate magnetic flux losses caused by Nernst effects and reduce ignition requirements. However, the inclusion of high-Z materials may The two-layer magnetized liner target offers an alternative approach to magnetized target fusion implosions by incorporating high atomic number (Z) materials in the innermost layer to mitigate magnetic flux losses caused by Nernst effects and reduce ignition requirements. However, the inclusion of high-Z materials may lead to increased radiation losses due to mixing. This preliminary research on magnetized liner inertial fusion (MagLIF) utilizes germanium (Ge) doped with CH as a high-Z substitute in the liner to isolate the effects of magnetic Nernst advection and mixing. Compared to one-layer targets, the two-layer configuration demonstrates significant increases in temperature and magnetic flux, resulting in a 154% improvement in fusion yield. Different concentrations of CH dopant are introduced into the inner layer of Ge, and the effects of CH concentrations on fusion yield are analyzed. The study shows that using low concentration CH-doped Ge as inner layer of liner can enhance fusion yield..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 092002 (2024)
Special Column on Ion Beam Science and Technology and Its Applications
Simulation of the thermal effect on high power Bi target for the large-scale 211At production
Jie Xiong, Guoliang Dou, Liangting Sun, Yang Wang, Zhi Qin, Jieru Ren, Yongtao Zhao, and Hongwei Zhao
To improve the reliability and operation life of metallic Bi targets for the production of medical isotope 211At using high current α beam, several beam uniformization methods were simulated and compared. The thermal effect of 500 eμA α beam bombarding a Bi target with wobbler magnet was modeled and analyzed by computaTo improve the reliability and operation life of metallic Bi targets for the production of medical isotope 211At using high current α beam, several beam uniformization methods were simulated and compared. The thermal effect of 500 eμA α beam bombarding a Bi target with wobbler magnet was modeled and analyzed by computational fluid dynamics (CFD) method, which provided key technical support for the design of target system and the improvement of target life time. The results showed that the peak beam thermal effect on the target was obviously reduced by applying beam scanning. In front of the target, a wobbler magnet was used to periodically scan the beam, which could effectively reduce the temperature on Bi target surface. With a scanning frequency of 50 Hz, the highest temperature on Bi target was 189.8 ℃, lower than the melting point of Bi metal (271.3 ℃), which could meet the temperature requirement of Bi target under such a high beam power condition..
High Power Laser and Particle Beams
- Publication Date: Sep. 15, 2024
- Vol. 36, Issue 9, 094005 (2024)