Journals >High Power Laser and Particle Beams
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2024
Volume: 36 Issue 3
27 Article(s)
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[in Chinese]
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 1 (2024)
[in Chinese]
A hierarchical method for verification of particle-in-cell/ Monte Carlo collision modelling on plasma discharges
Tianbo Shang, Wei Yang, Mengmeng Song, and Qianhong Zhou
The verification of scientific computing currently places a strong emphasis on grid discretization methods for systems of deterministic partial differential equations. However, verifying particle-in-cell (PIC) simulations, which employ a particle-mesh method to model discharging plasmas, presents distinctive challengesThe verification of scientific computing currently places a strong emphasis on grid discretization methods for systems of deterministic partial differential equations. However, verifying particle-in-cell (PIC) simulations, which employ a particle-mesh method to model discharging plasmas, presents distinctive challenges. Firstly, PIC simulations require discretization not only in time and space but also in macro-particle weights. Secondly, challenges arise regarding the utilization of the discretized particle phase space distribution function for verification purposes. Thirdly, the interpolation of electric fields and charge distribution can significantly impact the overall accuracy of PIC convergence.When PIC methods are integrated with Monte Carlo (MC) methods, discretization and stochastic errors often combine, necessitating Richardson extrapolation in conjunction with ensemble averaging.To tackle these challenges, this paper introduces a hierarchical verification approach. It commences with order-of-accuracy tests for individual particle trajectories, electromagnetic field solvers, and binary-particle collisions. Discretization errors for integrated PIC and MC modules are then evaluated using classical physical models that possess exact solutions, such as space-charge-limited current and Fourier flow in gases. Finally, a code-to-code comparison is performed with benchmark examples of simplified discharge simulations..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033002 (2024)
Design of an S-band ultra-wideband energy selective surface
Tao Zhou, Ning Hu, Longjie Gai, Wentao Huang, Yanlin Xu, and Peiguo Liu
In this paper, an energy selective surface (ESS) structure working in S-band is designed, which can realize ultra-wideband adaptive strong electromagnetic (EM) protection. The ESS is composed of top and bottom layers. The top layer includes two parallel strips and a patch, on which two PIN diodes are loaded, and the boIn this paper, an energy selective surface (ESS) structure working in S-band is designed, which can realize ultra-wideband adaptive strong electromagnetic (EM) protection. The ESS is composed of top and bottom layers. The top layer includes two parallel strips and a patch, on which two PIN diodes are loaded, and the bottom layer includes two vertical stripes. When the incident EM intensity is lower than the threshold value, the ESS works in the transparent state, which makes the electromagnetic waves propagate; When the EM intensity exceeds the threshold value, the induced voltage generated between the metal strips and patch makes the PIN diode turn on, and the ESS enters the protective state and the electromagnetic wave is shielded. The working principle of the ESS is analyzed by simulating the surface current and electric field distribution in PIN diode on-off state and equivalent circuit model. The prototype was processed by PCB process and the insertion loss of weak field incident and shielding efficiency of strong field incident were measured. The experimental and simulation results are in great agreement. The results show that in the transparent state, the operating center frequency of the ESS is 2.7 GHz, and the operating band with insertion loss less than 1 dB is 2.2-3.5 GHz. In the protective state, the shielding efficiency of the operating band is greater than 10 dB, which meets the requirement of ultra-wideband..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033003 (2024)
Design of X-band low phase noise sapphire oscillator
Ying Liu, Yisong Xiong, Yue Li, Xin Li, Cheng Zeng, Junsong Ning, Shirong Bu, Zhanping Wang, Xiaoyu Zhang, Shaoyang Liu, and Wanting Guo
The paper presents the design and temperature control of a low phase noise sapphire oscillator. Utilizing the theory of sapphire resonator, finite element simulation software is employed to accomplish the design process. The measured center frequency of the sapphire resonator is 9.84 GHz with a loaded Q value of 113000The paper presents the design and temperature control of a low phase noise sapphire oscillator. Utilizing the theory of sapphire resonator, finite element simulation software is employed to accomplish the design process. The measured center frequency of the sapphire resonator is 9.84 GHz with a loaded Q value of 113000. By utilizing the sapphire resonator as a frequency selection network along with components such as amplifier, filter, phase shifter and coupler, a low-noise sapphire oscillator is constructed. The output frequency of this oscillator is 9.84 GHz with an output power of 9 dBm. It exhibits excellent performance in terms of phase noise: -117 dBc/Hz at 1 kHz deviation from the carrier, -144 dBc/Hz at 10 kHz deviation from the carrier, and -161 dBc/Hz at 100 kHz deviation from the carrier. This oscillator significantly enhances radar capabilities for the detection of low-speed and small targets..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033004 (2024)
Simulation of high power microwave oscillator with locked frequency and phase based on nested structure
Jiawen Li, Xingjun Ge, Fangchao Dang, Peng Zhang, Rujin Deng, Xiaodong Hu, and Zhimin Li
The power capacity of high-power microwave generating devices is improved by increasing the overmode ratio of the slow wave structure. The nested structure allows the use of the hollow or inner conductor structure of the overmode device, while the low impedance of the nested structure device makes it a good match for lThe power capacity of high-power microwave generating devices is improved by increasing the overmode ratio of the slow wave structure. The nested structure allows the use of the hollow or inner conductor structure of the overmode device, while the low impedance of the nested structure device makes it a good match for low-impedance pulsed power sources. A high-power microwave oscillator with locked frequency and phase is proposed based on the nested structure. Compared with the traditional method to lock phase and frequency, a method based on coupling waveguide is proposed to realize the locked frequency and phase. The microwave generated by the outer relativistic klystron oscillator (RKO) or inner RKO leaks into the other RKO through the coupling waveguide to premodulate the electron beam to lock phase and frequency. In addition, a dual-way power combiner is designed at the operating frequency of the oscillator to realize the combination of the inner and outer high-power microwave. The power combiner can make up for the phase difference between the two output ways, increasing the power combination efficiency to 98.3%. When the diode voltage is 575 kV and the magnetic field is 0.6 T, the output power of inner and outer RKOs are 2.2 GW and 3.2 GW, respectively, with the frequency difference fluctuating less than 20 MHz and the phase difference stabilized near 10°; loading the designed power combiner, high power microwave with power of 5.31 GW and efficiency of 32.2% is obtained. The results show that the oscillator saturation time is shortened and the output power is increased when the nested device is in the locked state..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033005 (2024)
Coupling response of unmanned aerial vehicle antennas under high-power microwave radiation
Min Zhao, Yazhou Chen, Xing Zhou, Yaning Nie, and Huijuan Li
Unmanned aerial vehicle (UAV) is vulnerable to interference and even damage under high-power microwave (HPM) radiation, and its airborne antennas are important coupling pathways. To study the coupling response of its airborne antennas under HPM radiation, taking the datalink antenna and the navigation receiver as the rUnmanned aerial vehicle (UAV) is vulnerable to interference and even damage under high-power microwave (HPM) radiation, and its airborne antennas are important coupling pathways. To study the coupling response of its airborne antennas under HPM radiation, taking the datalink antenna and the navigation receiver as the research objects, their coupling models under HPM radiation are established according to the actual layout of the UAV. The accuracy of the antenna models are verified by their far-field pattern and S11 parameter of the antenna. The coupling voltages induced on the ports of the datalink antenna and the navigation receiver antenna under HPM radiation with different scenarios and parameters are obtained, and typical scenario experiment is carried out to verify the simulation results. The results show that the coupling voltage induced on the port of the datalink antenna under L-band HPM radiation is higher than that under S, C and X bands HPM radiation. Compared with the horizontal polarization, HPM with the vertical polarization has better interference effect on the datalink of UAV, and the coupling voltage is linearly related to the radiated field strength and is less affected by the pulse width and the rise time of HPM. The coupling voltage induced on the port of the navigation receiver antenna under space-based HPM is higher than that under ground-based HPM. The research will provide the theoretical references in attacking UAVs with HPM weapons..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033006 (2024)
Design and experimental study of S-band permanent magnet relativistic magnetron
Yanyan Zhang, Hong Chen, Jianjun Xu, Kun Deng, Dongsheng Liu, and Qiao Liu
In this paper, an S band all cavity extraction relativistic magnetron with permanent magnet is theoretically designed and numerically simulated, and an experimental investigation is also carried out. The initial structural parameters of the relativistic magnetron are obtained through theoretical analysis, and the modelIn this paper, an S band all cavity extraction relativistic magnetron with permanent magnet is theoretically designed and numerically simulated, and an experimental investigation is also carried out. The initial structural parameters of the relativistic magnetron are obtained through theoretical analysis, and the model is optimized by particle simulation. The permanent magnetic field generation structure is designed according to the needs of the guiding magnetic field. Simulation results reveal that this permanent magnet relativistic magnetron could generate a microwave power of 1.978 GW corresponding to a power conversion efficiency of 49.2% when the driver voltage is 500 kV. This permanent magnet tube is tested on the high-voltage pulse drive platform. In the experiment, gigawatt class output microwave power was obtained, corresponding to a power conversion efficiency of about 40%. The experimental results are in good agreement with the simulation results..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033007 (2024)
Design and research of C-band miniaturized high power microwave output window
Pengxin Mao, Yongliang Tang, Xiufang Wang, and Qingxiang Liu
To meet the high power capacity and compact application requirements of microwave output window in high power microwave system, a C-band miniaturized high power microwave output window is designed based on the design theory of traditional box window by optimizing the form structure and adding transition segments. By inTo meet the high power capacity and compact application requirements of microwave output window in high power microwave system, a C-band miniaturized high power microwave output window is designed based on the design theory of traditional box window by optimizing the form structure and adding transition segments. By increasing the surface area of the window and changing the connection mode of the rectangular waveguide-circular waveguide transition segment, the power capacity can be increased and the longitudinal size of the microwave output window can be reduced. The “I” form structure can effectively suppress the influence of multipactor near the triple point(vacuum-media-mental) on the performance of the output window. On the basis of electromagnetic simulation, the multipactor near the triple point of the microwave output window is studied by using the Particle-in-Cell method. From the microscopic point of view, it is further confirmed that the “I” form structure can make the position of the triple point move, reduce the probability of multipactor generated by the electrons emitted by the triple point on the surface of the window, and reduce the breakdown risk of the microwave output window. The design results show that the main mode reflection coefficient of the microwave output window at the center frequency is lower than 0.01, the transmission efficiency is higher than 99.9%, and the power capacity can reach 47.9 MW..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033008 (2024)
A technology for generating intense annular electron beam with variable beam radius and its application
Fugui Zhou, Dian Zhang, Jun Zhang, Yinghao Chen, Zhenxing Jin, and Shengyue Zhou
Intense annular electron beam with variable beam radius has important applications in high power microwave (HPM) generation devices with cross-band frequency hopping. This paper proposes a technology of changing the radius of annular electron beam based on the adjustment of the externally guided magnetic field. The corIntense annular electron beam with variable beam radius has important applications in high power microwave (HPM) generation devices with cross-band frequency hopping. This paper proposes a technology of changing the radius of annular electron beam based on the adjustment of the externally guided magnetic field. The core components of the technology include an annular cathode, an anode, an electron beam transfer channel, two transmission channels and an external guide magnet (a three-segment solenoid) system. When the current of the solenoid differs, the solenoid system can generate different magnetic field distributions. In the particle-in-cell (PIC) simulation, when the currents of the three segments are 1 025 A, 107 A, 107 A and 300 A, 300 A, 0 A respectively, the solenoid generates two magnetic fields to achieve the change of the electron beam radius. Based on the theory of single particle motion, this paper deduces the expression of the trajectory of electron beam guided by the gradient magnetic field, explains the principle of the electron beam radius variation under the gradient magnetic field, and investigates the influence of the slope and range of the gradient magnetic field on the electron beam radius. In the cross-band HPM devices simulation, the output power of X-band is 1.6 GW, the frequency is 8.2 GHz, and the power efficiency is 40%. The Ku-band has achieved a power output of 1.5 GW, a frequency of 14.4 GHz, and a power efficiency of 38%..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033009 (2024)
Low magnetic field X-band over-mode relativistic backward wave oscillator with dual-cavity reflector
Jingfan Zuo, Shifeng Li, Yang Wu, Hua Huang, Limin Sun, and Falun Song
This paper propose an X-band over-mode high-efficiency relativistic backward wave oscillator (RBWO), whose main structure includes a dual resonant cavity reflector, a periodic slow wave structure and an inserted coaxial mode selector. The RBWO uses an over-mode structure and transmits a pure TM01 mode in the output wavThis paper propose an X-band over-mode high-efficiency relativistic backward wave oscillator (RBWO), whose main structure includes a dual resonant cavity reflector, a periodic slow wave structure and an inserted coaxial mode selector. The RBWO uses an over-mode structure and transmits a pure TM01 mode in the output waveguide. The dual-cavity reflector enables the slow-wave structure to achieve good isolation from the diode region under over-mode conditions, and at the same time provides sufficient pre-modulation for the electron beam to achieve high microwave conversion efficiency under low magnetic field. The addition of the coaxial inner conductor allows the device to work in TM02 mode, while eliminating other unnecessary mode competition, achieving higher power capacity. In the PIC simulation, under the conditions of a guiding magnetic field of 0.63 T, a diode voltage of 850 kV, and a beam current of 11.74 kA, a microwave output power of 3.5 GW was obtained, and the device efficiency was about 35%..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033010 (2024)
Influence of repeated frequency UWB electromagnetic pulse on GPS navigation receiver
Ming Hu, Shengxian Chen, Yonglong Li, and Xuelin Yuan
While the global positioning system (GPS) is widely used, it is also susceptible to external interference. Therefore, it is of great significance to study the reliability of GPS navigation receivers. Ultra-wideband (UWB) electromagnetic pulse has a steep rising edge and a wide spectrum, it can interfere with GPS and haWhile the global positioning system (GPS) is widely used, it is also susceptible to external interference. Therefore, it is of great significance to study the reliability of GPS navigation receivers. Ultra-wideband (UWB) electromagnetic pulse has a steep rising edge and a wide spectrum, it can interfere with GPS and has become a new navigation interference method. This paper explores the interference mechanism of repeated frequency UWB electromagnetic pulses to GPS navigation receivers by analyzing their energy spectrum line distribution and studies the relationship between their interference effect on GPS receivers and the pulse parameters. The results show that repeated frequency UWB electromagnetic pulses can cause nonlinear interference to the radio frequency front-end circuit of the navigation receiver, reducing the receiver's acquisition performance. Increasing the pulse field strength or repetition frequency can enhance the interference effect and even cause the receiver to lose its acquisition ability..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033011 (2024)
Design and measurement of high Q-factor coaxial resonant cavity
Yankui Lü, Fuxiang Yang, Fangchao Dang, Xingjun Ge, and Juntao He
With the development of high power microwave sources towards high power, high frequency and long pulse, coaxial relativistic klystron amplifiers (RKA) have become one of the research hotspots in recent years. However, its development is limited by self-excited oscillation, etc. Therefore, a high Q-factor single-gap coaWith the development of high power microwave sources towards high power, high frequency and long pulse, coaxial relativistic klystron amplifiers (RKA) have become one of the research hotspots in recent years. However, its development is limited by self-excited oscillation, etc. Therefore, a high Q-factor single-gap coaxial resonator is designed in this paper to suppress the self-oscillation caused by TEM mode leakage of the coaxial RKA. Through the theoretical analysis and simulation of TM01 mode and TEM mode conversion in a single-gap coaxial resonator, it is found that the depth difference and axial dislocated values of the upper and lower slots of the coaxial resonator have a great influence on the change of its Q factors. When the depth difference and axial dislocation value of the upper and lower slots are 0.3 mm and 0 mm respectively, the Q factor of the coaxial resonator has the maximum value (18 764). This means that the conversion between the two modes in the resonator is minimal, greatly reducing the risk of self-oscillation between several cascaded coaxial resonators. When three cascaded high-Q-factor single-gap coaxial resonators are applied to the compact coaxial RKA, the output microwave power of the device is stable, the spectrum is pure, and there are no self-excited oscillations in the simulation and experiments..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033012 (2024)
Study on the properties of low dielectric loss composite insulating materials for superconducting cables
Mingyang Wang, Hailian Dong, Pengyu He, and Tao Jiang
Compared with traditional cables, superconducting cables have the advantages of no resistance loss, large transmission capacity and high reliability. However, polypropylene laminated paper as its main insulation has high loss factor, which leads to large dielectric loss in the operation of superconducting cables and inCompared with traditional cables, superconducting cables have the advantages of no resistance loss, large transmission capacity and high reliability. However, polypropylene laminated paper as its main insulation has high loss factor, which leads to large dielectric loss in the operation of superconducting cables and increases the load of cooling system. In this paper, polytetrafluoroethylene filter paper with low loss factor is used to replace the kraft paper layer in the polypropylene lamination paper, and a sandwich structure composite insulation with porous surface can be formed by being hot-pressed with the polypropylene film. The test results show that replacing the polypropylene lamination paper with polytetrafluoroethylene/polypropylene composite material as the main insulation in the superconducting cable will reduce by more than half the dielectric loss. At the same time, due to the smaller dielectric constant difference between the polytetrafluoroethylene/polypropylene composite material and the liquid nitrogen used as the coolant in the high temperature superconducting cable and the volume effect of liquid nitrogen breakdown, the low dielectric loss composite insulation made of polytetrafluoroethylene filter paper with smaller aperture has stronger resistance to partial discharge and higher AC insulation breakdown strength, which can greatly improve the insulation reliability of the high temperature superconducting cable..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033013 (2024)
[in Chinese]
Achieving prolonged continuous operation of a self-designed 28 GHz/50 kW gyrotron
Linlin Hu, Qili Huang, Tingting Zhuo, Peng Hu, Shenggang Gong, Dimin Sun, Yi Jiang, Guowu Ma, Hongbin Chen, and Hongge Ma
This paper presents the latest experimental results of a 28 GHz/50 kW continuous wave gyrotron, developed by Institute of Applied Electronics, Chinese Academy of Engineering Physics for applications in the electron cyclotron resonance heating (ECRH) system of magnetic confinement fusion devices, the electron cyclotron This paper presents the latest experimental results of a 28 GHz/50 kW continuous wave gyrotron, developed by Institute of Applied Electronics, Chinese Academy of Engineering Physics for applications in the electron cyclotron resonance heating (ECRH) system of magnetic confinement fusion devices, the electron cyclotron resonance (ECR) ion source in heavy ion accelerators and frontier scientific explorations. Stable prolonged continuous operation at multiple power levels ranging from 10 kW to 50 kW has been achieved through structural optimization and stability design verification. Typical sustained operation was observed at 16 kW for 3000 s, 26 kW for 900 s, 46 kW for 1800 s, and 50 kW for 300 s. Notably, a record-breaking continuous stable operation lasting up to 400 min was accomplished at a power level of 32 kW. This achievement represents China’s first successful development of a medium-power gyrotron capable of hour-level continuous operation..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 033001 (2024)
[in Chinese]
Development of mechanical property analysis program for space thermionic fuel element
Wenyu Yang, Xiang Chai, Enping Zhu, and Xiaojing Liu
To predict the safety performance of fuel elements during operation of a space thermionic reactor, this study developed a mechanical performance analysis program for fuel elements, and conducted high-precision simulation of stress, strain, and geometric deformation for the multi-layer cylindrical TOPAZ-II thermionic fuTo predict the safety performance of fuel elements during operation of a space thermionic reactor, this study developed a mechanical performance analysis program for fuel elements, and conducted high-precision simulation of stress, strain, and geometric deformation for the multi-layer cylindrical TOPAZ-II thermionic fuel element. The program takes into account the irradiation swelling of nuclear fuel under high-temperature radiation environment, and analyzes the mechanical response of the fuel pellet-emitter after contact, thereby quickly and accurately solving the mechanical state of the fuel pellet and emitter, to provide accurate prediction of the performance during operation of the space thermionic reactor. The results indicate that in normal operating conditions, the fuel of a space thermionic reactor undergoes significant swelling effects, which causes deformation that can lead to potential safety hazards such as reduced thermal-electric conversion efficiency and component failure..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 036001 (2024)
Research on diagnosis of fuel defects in operating pressurized water reactors
Pengtao Fu, Anlong Zhang, and Peiyong Gu
Fuel cladding is the first barrier to confine the radionuclides produced in the reactor core. Once the fuel rods defect, fission product activity in the primary loops will increase and may lead to temporary shutdown of the reactor when fuel rod failure has deteriorated to certain levels. This paper introduces the theorFuel cladding is the first barrier to confine the radionuclides produced in the reactor core. Once the fuel rods defect, fission product activity in the primary loops will increase and may lead to temporary shutdown of the reactor when fuel rod failure has deteriorated to certain levels. This paper introduces the theoretical mechanism of production and migration of fission product from defective fuel rods to the primary loops in the operating pressurized water reactors. The analytical solution of fission product concentration in primary loops is got based on the first-order differential equations for steady operation. Based on the release-to-birth ratios for recoil and diffusion by least squares method, a method is developed to diagnose the status of fuel failure in pressurized water reactors, including fuel failure time, the degrees of defect size, the disseminated actinides, the average burnup and the fuel batch. The prediction results of fuel failure are verified well with that of a typical fuel failure with secondary degradation in one commercial pressurized water reactor, as well as those of the sipping test and the post irradiation examination..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 036002 (2024)
[in Chinese]
Effect of laser on the stopping power of a large range energetic Carbon ion in a two-component plasma
He Yi, Guiqiu Wang, Shixuan Wang, Xin Gao, and Dajun Liu
This paper, studies the influence of laser on the stopping power of a carbon ion in a two-component plasma, with emphasis on the effects of different laser amplitude, laser frequency, laser angle, plasma density, and plasma temperature on the stopping power based on the linearized Vlasov-Poisson model and molecular dynThis paper, studies the influence of laser on the stopping power of a carbon ion in a two-component plasma, with emphasis on the effects of different laser amplitude, laser frequency, laser angle, plasma density, and plasma temperature on the stopping power based on the linearized Vlasov-Poisson model and molecular dynamics simulation. The research results show that the influence of laser on stopping power is very obvious in all the projectile region. In the low energy region (the magnitude of incident velocity is 0-0.1 plasma electron thermal velocity), the energy loss of the carbon ion mainly comes from the contribution of ions in the plasma, especially when the incident velocity is around the plasma ion thermal velocity, the first peak of stopping power occurs. In the medium and high energy region (the magnitude of incident velocity is greater than 0.1 plasma electron thermal velocity), the energy loss of the carbon ion mainly comes from the contribution of electrons in the plasma, especially when the magnitude of incident velocity is around 1.5 times the plasma electron thermal velocity, the second peak of stopping power occurs. The bimodal structure of the stopping power of the carbon ion in the plasma reflects the contribution of ions and electrons to the stopping power in different energy regions. On the other hand, the increase of laser intensity or laser frequency can decrease the stopping power of the carbon ion. The stopping power will be enhanced with the increase of plasma density or the decrease of electron temperature. Such an enhancement is more significant for stopping power for the low energy peak caused by ions compared to high energy peak caused by electrons..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 034001 (2024)
Design and implementation of scanning magnet power supply based on PREF
Qi Fan, Hang Zang, Qi Guo, Hongbin Yan, Chengcheng Shi, Jingbin Shangguan, and Yun Zhang
The PREF device is a 10-60 MeV proton synchrotron jointly designed and built by Xinjiang Institute of Physics and Chemistry, Chinese Academy of Sciences and Institute of Modern Physics, Chinese Academy of Sciences, which is the only dedicated device for displacement damage effect simulation test in China. For the technThe PREF device is a 10-60 MeV proton synchrotron jointly designed and built by Xinjiang Institute of Physics and Chemistry, Chinese Academy of Sciences and Institute of Modern Physics, Chinese Academy of Sciences, which is the only dedicated device for displacement damage effect simulation test in China. For the technical requirements—the output current frequency of the scanning magnet power supply is 200 Hz, and the tracking error is less than ≤±5×10-3—of the device, three stage H-bridge series topology schemes are adopted, and the technical requirements are realized based on pulse width modulation through phase shift control. Simulation and test results show that the power supply can output high precision triangular wave current with peak-to-peak value of ±420 A, continuously adjustable amplitude and frequency to meet the requirements of engineering applications..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 034002 (2024)
[in Chinese]
Small sized bremsstrahlung conversion target
Xiaobing Jing, and Jinshui Shi
The paper aims to reduce the lateral size of the X-ray source in a linear induction accelerator and design a bremsstrahlung conversion target. Analyzing the trajectory of the electron beam during the focused shooting process, it is pointed out that the distribution of the same electron beam trajectory can be described The paper aims to reduce the lateral size of the X-ray source in a linear induction accelerator and design a bremsstrahlung conversion target. Analyzing the trajectory of the electron beam during the focused shooting process, it is pointed out that the distribution of the same electron beam trajectory can be described as either the transverse broadening of the electron beam at a certain longitudinal position or the axial distribution broadening when the electron beam maintains a small transverse size. Therefore, the concept design of a small-sized multi-layer target with multiple small targets placed near the waist to effectively block the focused electron beam is proposed. The EGS4 program was used to calculate the X-ray yield, and it was found that the change in X-ray yield was relatively small when the target thickness changed within a certain range. Based on this rule, the structural design of a small-sized multi-layer target was completed. Further investigation was conducted on a design application example. When the minimum envelope diameter of the focused electron beam is 3 mm and the convergence angle is 100 mrad, compared to large-sized targets, using a designed small-sized multi-layer target can obtain an X-ray light source with an equivalent diameter reduction of about 50% and a yield reduction of about 10%. By adopting the proposed design method, it is expected to obtain X-ray light sources with lateral dimensions smaller than the minimum envelope size of the electron beam under the same electron beam quality and focusing conditions, which has certain application value..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 034003 (2024)
Development of the NFTHz accelerator beam profile measurement system
Wenchao Zhu, Zhengyu Wei, Chunjie Xie, Zeran Zhou, Lin Wang, and Yu Liang
The “Composite Light Source” project of the National Synchrotron Radiation Laboratory, Terahertz Near-Field High-Flux Material Property Testing System, consists of an approximately 3-meter electron linear accelerator. To characterize the performance of the accelerator and monitor the status of the beam, it is necessaryThe “Composite Light Source” project of the National Synchrotron Radiation Laboratory, Terahertz Near-Field High-Flux Material Property Testing System, consists of an approximately 3-meter electron linear accelerator. To characterize the performance of the accelerator and monitor the status of the beam, it is necessary to measure the beam size. Specifically designed for the terahertz linear accelerator, a beam size measurement system based on the EPICS distributed system has been developed. A beam spot detector is taken for the conversion of the beam spot into an optical spot and a remote mirror is taken to image the optical spot onto a CCD camera for image acquisition. Subsequently, the camera-captured image data is integrated into the EPICS database using ADAravis. Due to the dark current and radiation environment, salt-and-pepper noise is present in the acquired images. Therefore, a Convolutional Neural Network (CNN) is employed to suppress the salt-and-pepper noise in the images. Finally, Gaussian fitting is applied to calculate the beam cross-sectional dimensions from the images. The experimental results indicate that the CNN can effectively eliminate salt-and-pepper noise, and the resolution of this system is 15.8 μm, which satisfies the design requirement..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 034004 (2024)
[in Chinese]
Optimization of tetracycline degradation by nanosecond pulsed gas-liquid discharge with needle-water configuration
Pengju Chen, Zikai Zhou, Sen Wang, and Zhi Fang
Water pollution caused by the overuse of antibiotics poses a major threat to the natural environment and human health. As a green and environmentally friendly advanced oxidation technology, low-temperature plasma is considered to be one of the most promising antibiotic degradation methods, but it needs to be further imWater pollution caused by the overuse of antibiotics poses a major threat to the natural environment and human health. As a green and environmentally friendly advanced oxidation technology, low-temperature plasma is considered to be one of the most promising antibiotic degradation methods, but it needs to be further improved in terms of degradation efficiency and energy efficiency. In this study, transient spark discharge was obtained by using nanosecond pulse power supply with a needle-water electrode configuration, and applied to tetracycline degradation in water. The effect of pulse voltage, frequency, initial concentration, initial pH value on tetracycline degradation was studied, and the results show that the degradation rate of tetracycline was the highest under the condition that the initial concentration was 50 mg/L, the pulse voltage was 9 kV, the frequency was 2 kHz, the initial pH is neutral, and the degradation rate reached 91.6% when the processing time was 10 min. The energy efficiency and electrical energy per order are 0.165 g·kW-1·h-1 and 0.78 kW·h·m-3, respectively. Free radical quenching experiments showed that hydroxyl radicals (·OH) played a major role in the degradation of tetracycline, while H2O2 and O3 played a slightly weaker role. Cytotoxicity experiments also showed that the toxicity of the solution decreased significantly after 10 min of gas-liquid discharge treatment..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 035001 (2024)
Research on two-channel high-voltage pulse generator with reverse bias voltage
Zi Li, Di Zhang, Song Jiang, Yonggang Wang, and Junfeng Rao
The influence of electric field penetration on mass spectrometer can be improved by adjusting the reverse bias voltage to improve the resolution of mass spectrometer. To meet the different output waveform requirements of mass spectrometers, this paper proposes a pulse generator that can simultaneously output two pulsesThe influence of electric field penetration on mass spectrometer can be improved by adjusting the reverse bias voltage to improve the resolution of mass spectrometer. To meet the different output waveform requirements of mass spectrometers, this paper proposes a pulse generator that can simultaneously output two pulses of the same voltage amplitude and with opposite polarities, and a negative DC bias voltage is coupled to the high-voltage positive pulse. Only one charging power source is needed to generate both positive and negative pulsed electric fields. This paper analyzes the synchronous driving effect of the series switch, and then solves the problem of uneven charging voltage of the series capacitors by adding the compensation windings and parallel resistors. The difference of charging voltage between four capacitors is within 0.1%. A 4-stage prototype was constructed. This pulse generator can generate a high-voltage positive pulse with amplitude from 0 to 1.5 kV and adjustable pulse width from 2 to 10 µs and coupled with a negative bias voltage with amplitude from 0 to -200 V, and a high-voltage negative pulse with amplitude from 0 to -1.5 kV and adjustable pulse width from 2 to 10 µs. All the rising edges are shorter than 30 ns. The pulse generator can achieve adjustable output voltage, pulse widths and frequencies..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 035002 (2024)
Study of low-jitter laser-triggered pseudo-spark switches
Mingjie Yang, Hongfei Yang, Ming Zhang, and Bo Qu
Pseudo-spark switches have been successfully used in a variety of pulsed power applications, including the European Large Hadron Collider, anti-missile radar systems, and aero-engine ignition. For such applications, it is important to reduce the delay and jitter of the switch to improve stability. In this paper, a lasePseudo-spark switches have been successfully used in a variety of pulsed power applications, including the European Large Hadron Collider, anti-missile radar systems, and aero-engine ignition. For such applications, it is important to reduce the delay and jitter of the switch to improve stability. In this paper, a laser-triggered pseudo-spark switch is designed using a laser with a wavelength of 532 nm, and the anode firing delay time and jitter of the laser-triggered pseudo-spark switch are tested under different air pressures, operating voltages, and triggering energies. The test results show that increasing the laser energy can reduce the delay and jitter of the switch, and the laser energy threshold of 1.5 mJ for switch stability can make the jitter of the switch less than 1 ns, and the delay and jitter of the switch no longer change significantly with continuing increase of the trigger energy; in addition, increasing the hydrogen pressure inside the tube can reduce the delay and jitter of the switch; when the trigger energy is large enough, changing the anode voltage does not change the delay and jitter of the switch..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 035003 (2024)
[in Chinese]
Characteristic analysis of P-SP topology wireless power transfer system based on parity-time-symmetric principle
Xiyu He, Feng Guo, and Xingpeng Xu
The parity time (PT) symmetry principle has been proved to be a powerful tool to improve the degree of freedom of wireless power transfer (WPT) systems. However, the operating range of the P-P (parallel-parallel) topology WPT system based on the PT symmetry principle is still limited. To solve this problem, a P-SP (serThe parity time (PT) symmetry principle has been proved to be a powerful tool to improve the degree of freedom of wireless power transfer (WPT) systems. However, the operating range of the P-P (parallel-parallel) topology WPT system based on the PT symmetry principle is still limited. To solve this problem, a P-SP (series-parallel) compensated WPT system based on PT symmetry principle is proposed. The circuit model of the system is simplified by the equivalent circuit method, and the influence of the capacitance distribution ratio on the oscillation frequency, the critical coupling coefficient, the coupling coefficient satisfying the system entering the PT symmetric region, the load resistance range and the transmission efficiency is analyzed by the coupled mode theory. A prototype is built to carry out experiments to test the applicability of the proposed method. The results show that the transmission distance can be expanded from 110 mm to 210 mm with only 2% loss of system transmission efficiency. Hence, preparations are made to expand the application scope, increase application scenarios, and optimize the working performance of the sending and receiving module units in the laser wireless charging system..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 039001 (2024)
[in Chinese]
Simulation of light field regulation based on micro-nano structure and material properties
Xinzhi Zheng, Shiji Dou, Xiang Liu, Chenxi Zhao, Shilong Zhao, Yue Yang, Shaoyi Wang, Zongqing Zhao, and Yujie Ma
The finite-difference time-domain algorithm (FDTD) was used to simulate the optical field distribution of the micro-nano structure target, explore the optical transmission mechanism in the micro-nano structure target, and analyze the influence of material properties and structural parameters on the optical transmissionThe finite-difference time-domain algorithm (FDTD) was used to simulate the optical field distribution of the micro-nano structure target, explore the optical transmission mechanism in the micro-nano structure target, and analyze the influence of material properties and structural parameters on the optical transmission characteristics and optical field distribution. Based on the simulation results of optical field distribution and evolution, the laser transmission characteristics in the nano-wire and nano-pore array targets of semiconductor alumina, insulator silicon dioxide and metal copper with different electrical conductivity are compared, and the modifications of optical field distribution during optical transmission are analyzed. The results show that the optical transmission characteristics and optical field distribution in the target can be modulated by changing the diameter and spacing of the holes (nanowires) in the target structure, and the optical field can be periodically oscillated between the dielectric material and the vacuum region, or transmitted in a stable state. When the laser is transmitted in the copper nanopore array, the light transmittance increases with the increase of the hole radius. Based on the simulation results of light field distribution and evolution, the laser transmission properties of different materials and micro-nano structure targets are compared, the physical images and corresponding phenomena are given, and the micro-nano structure target design is given according to the requirements of light field regulation..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 031002 (2024)
Performance research and parameter optimization of 15 nm Bulk nFinFET device
Tianhao Hou, Jieqing Fan, Qiang Zhao, Fang Zhang, Jianhong Hao, and Zhiwei Dong
Due to the growing severity of the short-channel effect in semiconductor devices, a new type of device, the FinField-Effect Transistor (FinFET), has been proposed, developed and applied. This paper aims to establish a 15 nm n-type Bulk FinFET device model to investigate the impact of basic structural parameters, deviceDue to the growing severity of the short-channel effect in semiconductor devices, a new type of device, the FinField-Effect Transistor (FinFET), has been proposed, developed and applied. This paper aims to establish a 15 nm n-type Bulk FinFET device model to investigate the impact of basic structural parameters, device temperature, and gate material on the performance of Bulk FinFETs. Simulations are conducted to analyze the effect of different gate lengths, fin widths, fin heights, channel doping concentration, device operating temperature, and gate materials on the performance of FinFETs. The results show that increasing the gate length, decreasing the fin width, and increasing the fin height can effectively suppress the short-channel effect. Moreover, the channel doping concentration below 1×1017 cm-3 has little effect on the device characteristics, while high doping concentration causes device failure. Additionally, increasing the operating temperature leads to device performance degradation. Finally, using high K dielectric material as the gate material is found to enhance device performance compared to using conventional SiO2 material..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 031003 (2024)
[in Chinese]
2 kW fiber laser pumped by long-wavelength laser diodes
Peng Wang, Xiangming Meng, Hanshuo Wu, Yun Ye, Baolai Yang, Xiaoming Xi, Chen Shi, Hanwei Zhang, Xiaolin Wang, Fengjie Xi, Zefeng Wang, Xiaojun Xu, Pu Zhou, and Jinbao Chen
The high-power fiber laser pumped by laser diodes (LDs) has the advantages of high efficiency, small size, light weight, and good stability, and has been widely used in many fields such as industrial processing. To improve the absorption rate of pump laser, the 915 nm and 976 nm LDs are commonly used as the pump sourceThe high-power fiber laser pumped by laser diodes (LDs) has the advantages of high efficiency, small size, light weight, and good stability, and has been widely used in many fields such as industrial processing. To improve the absorption rate of pump laser, the 915 nm and 976 nm LDs are commonly used as the pump source of the traditional fiber lasers. The quantum defect and pump absorption coefficient are comparatively high in the fiber lasers pumped by these LDs, which leads to low transverse mode instability (TMI) threshold. To improve quantum efficiency and potential TMI threshold, the fiber laser directly pumped by LDs with wavelength longer than 1010 nm is proposed. An oscillating-amplifying integrated laser was built, and 2.05 kW output laser with beam quality M2 of 1.7 was realized when the fiber laser was pumped by 1010 nm LDs with maximum pump power of 2.56 kW. In the future, fiber laser with higher output power and better beam quality can be realized by increasing the pump power and optimizing the fiber characteristics..
High Power Laser and Particle Beams
- Publication Date: Mar. 15, 2024
- Vol. 36, Issue 3, 031001 (2024)
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