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, Available online ,
doi: 10.11884/HPLPB202537.250073
Abstract:
High power microwave (HPM) testing is a critical method for investigating the damage effects of semiconductor devices in strong electromagnetic environments. However, traditional testing methods rely primarily on manual operation, making it difficult to accurately determine device failure thresholds and affecting the repeatability and reliability of experiments. To enhance testing accuracy and reduce human error, this study designs an automated HPM pulse testing system and standardized testing procedure based on the damage mechanisms of semiconductor devices. A typical commercial low-noise amplifier (LNA) is selected as the research subject, and its damage threshold under HPM pulses is systematically evaluated. By synchronously measuring the device's time-domain response, frequency characteristics, and current variations, and comparing parameters before and after failure, the failure threshold is precisely identified. Furthermore, a systematic assessment of primary, secondary, and tertiary damage stages of the failed device is conducted, with an analysis of the cumulative damage effects on key device parameters based on microscopic physical mechanisms to reveal the failure mechanisms. The proposed system and evaluation method can be applied to the reliability assessment of semiconductor devices in HPM environments, providing experimental support for device robustness analysis and optimization.
High power microwave (HPM) testing is a critical method for investigating the damage effects of semiconductor devices in strong electromagnetic environments. However, traditional testing methods rely primarily on manual operation, making it difficult to accurately determine device failure thresholds and affecting the repeatability and reliability of experiments. To enhance testing accuracy and reduce human error, this study designs an automated HPM pulse testing system and standardized testing procedure based on the damage mechanisms of semiconductor devices. A typical commercial low-noise amplifier (LNA) is selected as the research subject, and its damage threshold under HPM pulses is systematically evaluated. By synchronously measuring the device's time-domain response, frequency characteristics, and current variations, and comparing parameters before and after failure, the failure threshold is precisely identified. Furthermore, a systematic assessment of primary, secondary, and tertiary damage stages of the failed device is conducted, with an analysis of the cumulative damage effects on key device parameters based on microscopic physical mechanisms to reveal the failure mechanisms. The proposed system and evaluation method can be applied to the reliability assessment of semiconductor devices in HPM environments, providing experimental support for device robustness analysis and optimization.
, Available online ,
doi: 10.11884/HPLPB202537.250090
Abstract:
The structure of cantilever has existed in solid surface antenna for high power microwave system. It is difficult to maintain the low acceleration for feed source structure of solid surface antenna during external vibration excitation. The traditional dynamic vibration absorber has a good control effect on the structure of cantilever. However, the application of traditional dynamic vibration absorber is limited to small range of frequency. In order to improve above problem, one kind of active vibration control method combing with optimal passive absorber is provided in this paper. The best installed position of dynamic absorber is obtained by analyzing and simulating the model of solid surface antenna. Then, the optimal parameters are calculated according to the mathematical model of simplified passive dynamic absorber system. Furthermore, the sliding mode control parameters were obtained by considering the external excitation through active absorber method. The stability of sliding mode control method was demonstrated. This control method combined sliding mode control with active control absorber, which can reduce the vibration response of antenna effectively. This paper simulated the two-degree-of-freedom vibration system with active control absorber, which gave time-domain vibration response of antenna. The top point displacement of antenna under the predetermined excitation was reduced more than 95% by comparing the condition of no any strategy. It can be seen that feed source structure is in a more stable state under the action of this controller.
The structure of cantilever has existed in solid surface antenna for high power microwave system. It is difficult to maintain the low acceleration for feed source structure of solid surface antenna during external vibration excitation. The traditional dynamic vibration absorber has a good control effect on the structure of cantilever. However, the application of traditional dynamic vibration absorber is limited to small range of frequency. In order to improve above problem, one kind of active vibration control method combing with optimal passive absorber is provided in this paper. The best installed position of dynamic absorber is obtained by analyzing and simulating the model of solid surface antenna. Then, the optimal parameters are calculated according to the mathematical model of simplified passive dynamic absorber system. Furthermore, the sliding mode control parameters were obtained by considering the external excitation through active absorber method. The stability of sliding mode control method was demonstrated. This control method combined sliding mode control with active control absorber, which can reduce the vibration response of antenna effectively. This paper simulated the two-degree-of-freedom vibration system with active control absorber, which gave time-domain vibration response of antenna. The top point displacement of antenna under the predetermined excitation was reduced more than 95% by comparing the condition of no any strategy. It can be seen that feed source structure is in a more stable state under the action of this controller.
, Available online ,
doi: 10.11884/HPLPB202537.250103
Abstract:
This article mainly investigated on the incident and exit surfaces of terbium gallium garnet (TGG) magneto-optical elementsby damaged by the laser with wavelength of1064 nm through pump-probe imaging technology. The damage characteristics of terbium gallium garnet elements under fundamental 1064 nm pulse laser irradiation are studied. The results indicated that the coated TGG element exhibits a lower damage threshold at the incident surface compared with the exit surface, and the difference in damage morphology between the entrance and exit surface was mainly influenced by laser-induced plasma effects. It was found that the initial damage on the TGG incident surface gmainly came from impurities and defects in the coatings, and the separation of the film layer under high energy would be happened; The exit surface damage of coated TGG components was mainly induced by impurity defects in the substrate material, and the size of damage pits was increased gradually under higher laser energy. By analyzing the influence of factors such as laser pulse energy, plasma effect, and material damage response on the laser damage threshold, it provided important and significant reference for improving the anti-damage ability of TGG magneto-optical materials under high-power laser irradiation.
This article mainly investigated on the incident and exit surfaces of terbium gallium garnet (TGG) magneto-optical elementsby damaged by the laser with wavelength of
, Available online ,
doi: 10.11884/HPLPB202537.250043
Abstract:
With the advancement of active phased array radar, the requirement for transmit-receive (TR) power supplies in phased array radar has been escalating continuously. TR power supplies featuring wide input voltage range, high frequency, and high efficiency have emerged as the prevailing research orientation nowadays. Dual active bridge (DAB) converters can realize wide input voltage range and offer diversified control methods, thereby holding extensive application prospects in the domain of TR power supplies. Nevertheless, the system parameters such as inductance and switching frequency of DAB converters exert a considerable influence on the transmission power of TR power supplies and the on-state current of power MOSFETs. Based on the extend-phase-shift (EPS) modulation approach in DAB converters, this paper deduces the expressions of power transmission characteristics and inductor current magnitude, and proposes a parameter optimization design method for DAB circuits under EPS modulation. With the maximum transmission power considering overload requirements, the derating design of the maximum on-state current of MOS devices, and the minimum output voltage ripple frequency as restrictive indicators, the reliable operation area (ROA) is planned based on the parameter limitations, providing a reference basis for designing the corresponding inductance value, switching frequency, and optimizing DAB parameters. Finally, through the corresponding MATLAB simulation analysis of a two-output DAB converter, the simulation results indicate that the output voltage ripple, the on-state current of MOSFETs, and the output power conform to the expected demand indicators, validating the accuracy of the above theoretical derivation.
With the advancement of active phased array radar, the requirement for transmit-receive (TR) power supplies in phased array radar has been escalating continuously. TR power supplies featuring wide input voltage range, high frequency, and high efficiency have emerged as the prevailing research orientation nowadays. Dual active bridge (DAB) converters can realize wide input voltage range and offer diversified control methods, thereby holding extensive application prospects in the domain of TR power supplies. Nevertheless, the system parameters such as inductance and switching frequency of DAB converters exert a considerable influence on the transmission power of TR power supplies and the on-state current of power MOSFETs. Based on the extend-phase-shift (EPS) modulation approach in DAB converters, this paper deduces the expressions of power transmission characteristics and inductor current magnitude, and proposes a parameter optimization design method for DAB circuits under EPS modulation. With the maximum transmission power considering overload requirements, the derating design of the maximum on-state current of MOS devices, and the minimum output voltage ripple frequency as restrictive indicators, the reliable operation area (ROA) is planned based on the parameter limitations, providing a reference basis for designing the corresponding inductance value, switching frequency, and optimizing DAB parameters. Finally, through the corresponding MATLAB simulation analysis of a two-output DAB converter, the simulation results indicate that the output voltage ripple, the on-state current of MOSFETs, and the output power conform to the expected demand indicators, validating the accuracy of the above theoretical derivation.
, Available online ,
doi: 10.11884/HPLPB202537.250059
Abstract:
Microwave plasma has shown significant advantages in the fields of materials synthesis and chemical catalysis due to its high electron density and power utilization efficiency. To solve the problem that the small reaction area of traditional reactor limits its large-scale application, a three-prism microwave plasma reactor structure is innovatively proposed based on the principle of compressed waveguide. The design adopts a three-port symmetric configuration and introduces a compressed waveguide structure inside the cavity to achieve effective superposition and enhancement of the electric field. In addition, the influence of the port positions and microwave phases on the reflection coefficient and electric field distribution characteristics inside the cavity is systematically analyzed by using the multi-physical field coupling calculation method. The results show that optimizing the port position can reduce the reflection coefficient and improve the efficiency of energy utilization, regulating the port phase can effectively enhance the superposition effect of the electric field, so that the electric field is concentrated and widely distributed in the area of the quartz tube, and the peak field strength is as high as 1.64×105 V/m, which can satisfy the excitation conditions of the large-area plasma, and lays a foundation for the subsequent research of microwave plasma chemical reaction.
Microwave plasma has shown significant advantages in the fields of materials synthesis and chemical catalysis due to its high electron density and power utilization efficiency. To solve the problem that the small reaction area of traditional reactor limits its large-scale application, a three-prism microwave plasma reactor structure is innovatively proposed based on the principle of compressed waveguide. The design adopts a three-port symmetric configuration and introduces a compressed waveguide structure inside the cavity to achieve effective superposition and enhancement of the electric field. In addition, the influence of the port positions and microwave phases on the reflection coefficient and electric field distribution characteristics inside the cavity is systematically analyzed by using the multi-physical field coupling calculation method. The results show that optimizing the port position can reduce the reflection coefficient and improve the efficiency of energy utilization, regulating the port phase can effectively enhance the superposition effect of the electric field, so that the electric field is concentrated and widely distributed in the area of the quartz tube, and the peak field strength is as high as 1.64×105 V/m, which can satisfy the excitation conditions of the large-area plasma, and lays a foundation for the subsequent research of microwave plasma chemical reaction.
, Available online ,
doi: 10.11884/HPLPB202537.250065
Abstract:
As a new type of laser driver to suppress laser plasma instability, the low-coherence laser driver holds significant research value in the field of laser inertial confinement fusion. To achieve large-bandwidth and high-power low-coherence pulse parametric amplification, this study provides a detailed analysis of the parametric matching characteristics of DKDP crystals with varying deuteration rates under Type-I colinear phase matching conditions. The fundamental parameters, including phase-matching angles, walk-off angles, and parametric bandwidths, are determined. The theoretical parameter bandwidth of the 58% deuterium-doped DKDP crystal is 180 nm. On this basis, a design for broadband low-temporal-coherence optical parametric amplification based on 58%DKDP crystals is proposed, and the theoretical model and the corresponding numerical model are established by the three-wave coupled equations. Furthermore, an experimental investigation of parametric amplification based on 58%-deuterium-doped DKDP crystals is conducted. The center wavelength of the broadband low-coherence signal light is set at1053 nm, while the pump wavelength is fixed at 532 nm. The spectral width is 40 nm with a gain factor of 2.1. The results show that 58% DKDP crystal has a large gain bandwidth, and combined with the colinear phase-matching method, such crystals are expected to enable large-bandwidth and high-gain amplification of low-coherence light.
As a new type of laser driver to suppress laser plasma instability, the low-coherence laser driver holds significant research value in the field of laser inertial confinement fusion. To achieve large-bandwidth and high-power low-coherence pulse parametric amplification, this study provides a detailed analysis of the parametric matching characteristics of DKDP crystals with varying deuteration rates under Type-I colinear phase matching conditions. The fundamental parameters, including phase-matching angles, walk-off angles, and parametric bandwidths, are determined. The theoretical parameter bandwidth of the 58% deuterium-doped DKDP crystal is 180 nm. On this basis, a design for broadband low-temporal-coherence optical parametric amplification based on 58%DKDP crystals is proposed, and the theoretical model and the corresponding numerical model are established by the three-wave coupled equations. Furthermore, an experimental investigation of parametric amplification based on 58%-deuterium-doped DKDP crystals is conducted. The center wavelength of the broadband low-coherence signal light is set at
, Available online ,
doi: 10.11884/HPLPB202537.250063
Abstract:
With the rapid development of science and technology, the application of high-speed optical imaging and ultrafast diagnostic technologies in fields such as science, industry, national defense and medicine is becoming increasingly important. The synchroscan streak camera, as an ultrafast optical phenomenon detection instrument, is used in conjunction with high-repetition-frequency lasers to achieve high-precision time-synchronized pump detection. It realizes high signal-to-noise ratio detection by accumulating and amplifying weak optical signals. However, in the long-term working mode of the existing synchronous scanning circuit, the cumulative high-frequency noise of the signal source device increases accordingly. At the same time, there is a problem of lacking a specific impedance matching design method, which affects the improvement of the time resolution performance of the streak camera. This paper comprehensively considers various transformer structures and design schemes, conducts resonant matching design based on helical resonators, and carries out relevant simulation studies using finite element simulation. Through the adjustment of the parameters of the primary coil of the resonator, the matching between the output impedance of the RF power amplifier and the capacitive load is achieved. The research on resonant coupling boost of the design model shows that it can output peak voltage under a certain power input, verifying the effectiveness of the helical resonance method. Through the comparative analysis of noise response and time jitter, it is indicated that the design method in this paper can further improve the time resolution performance of synchronous scanning.
With the rapid development of science and technology, the application of high-speed optical imaging and ultrafast diagnostic technologies in fields such as science, industry, national defense and medicine is becoming increasingly important. The synchroscan streak camera, as an ultrafast optical phenomenon detection instrument, is used in conjunction with high-repetition-frequency lasers to achieve high-precision time-synchronized pump detection. It realizes high signal-to-noise ratio detection by accumulating and amplifying weak optical signals. However, in the long-term working mode of the existing synchronous scanning circuit, the cumulative high-frequency noise of the signal source device increases accordingly. At the same time, there is a problem of lacking a specific impedance matching design method, which affects the improvement of the time resolution performance of the streak camera. This paper comprehensively considers various transformer structures and design schemes, conducts resonant matching design based on helical resonators, and carries out relevant simulation studies using finite element simulation. Through the adjustment of the parameters of the primary coil of the resonator, the matching between the output impedance of the RF power amplifier and the capacitive load is achieved. The research on resonant coupling boost of the design model shows that it can output peak voltage under a certain power input, verifying the effectiveness of the helical resonance method. Through the comparative analysis of noise response and time jitter, it is indicated that the design method in this paper can further improve the time resolution performance of synchronous scanning.
, Available online ,
doi: 10.11884/HPLPB202537.250034
Abstract:
Ross pair and filters stack spectrometers are commonly used to detect hard X-ray spectrum. The results of filters stack spectrometer are highly sensitive to the profile of pre-estimated spectrum, while Ross pair is limited to discrete spectrum. Here we provide a Ross pair- filters stack mixed spectrometer, which combining the advantages of traditional filter stack spectrometers and Ross pairs. Each layer of the filter in the traditional filters stack spectrometer has been replaced with a Ross filters pair. Thus the discrete spectrum given by Ross pair can be used as the pre-estimated spectrum for the filters stack to solve the entire x-ray spectrum. Numerical and physical experiments using x-ray tube confirm that the present mixed spectrometer can provide more accurate spectral structures compared to traditional filter stack spectrometers. The compact and lightweight advantages make it widely applicable in hard x-ray spectral measurements.
Ross pair and filters stack spectrometers are commonly used to detect hard X-ray spectrum. The results of filters stack spectrometer are highly sensitive to the profile of pre-estimated spectrum, while Ross pair is limited to discrete spectrum. Here we provide a Ross pair- filters stack mixed spectrometer, which combining the advantages of traditional filter stack spectrometers and Ross pairs. Each layer of the filter in the traditional filters stack spectrometer has been replaced with a Ross filters pair. Thus the discrete spectrum given by Ross pair can be used as the pre-estimated spectrum for the filters stack to solve the entire x-ray spectrum. Numerical and physical experiments using x-ray tube confirm that the present mixed spectrometer can provide more accurate spectral structures compared to traditional filter stack spectrometers. The compact and lightweight advantages make it widely applicable in hard x-ray spectral measurements.
, Available online ,
doi: 10.11884/HPLPB202537.240429
Abstract:
In experimental studies of indirect drive inertial confinement fusion, both flat-response X-ray detector (FXRD) and space-resolving flux detector (SRFD) are commonly used to measure the radiation flux. The SRFD can measure radiation flux in localized spatial regions, thus avoiding signal disruption from non-targeted regions. However, direct experimental evidence has long been lacking to determine the consistency between SRFD and FXRD. In this paper, we introduce the experimental design of consistency measurement of the SRFD detector and FXRD detector at Shenguang 100 kJ facility, based on a small-plane target, which considers the field-of-view and signal amplitude of the two detectors. The experimental results show that the average difference in the radiation flux obtained by the two detectors is approximately 4.6%, which shows good consistency. Finally, the radiation flux given by the radiation hydrodynamic simulation is reasonably close to the experiment, with some differences in the behavior at the rising edge and decreasing edge. It is possibly related to the details of the simulation model. This work provides a good foundation for experimental studies related to the precision measurement of X-ray radiation flux in a local spatial region.
In experimental studies of indirect drive inertial confinement fusion, both flat-response X-ray detector (FXRD) and space-resolving flux detector (SRFD) are commonly used to measure the radiation flux. The SRFD can measure radiation flux in localized spatial regions, thus avoiding signal disruption from non-targeted regions. However, direct experimental evidence has long been lacking to determine the consistency between SRFD and FXRD. In this paper, we introduce the experimental design of consistency measurement of the SRFD detector and FXRD detector at Shenguang 100 kJ facility, based on a small-plane target, which considers the field-of-view and signal amplitude of the two detectors. The experimental results show that the average difference in the radiation flux obtained by the two detectors is approximately 4.6%, which shows good consistency. Finally, the radiation flux given by the radiation hydrodynamic simulation is reasonably close to the experiment, with some differences in the behavior at the rising edge and decreasing edge. It is possibly related to the details of the simulation model. This work provides a good foundation for experimental studies related to the precision measurement of X-ray radiation flux in a local spatial region.
, Available online ,
doi: 10.11884/HPLPB202537.250010
Abstract:
Microstrip Traveling Wave Tubes (TWTs) have garnered significant attention due to their potential applications in communication, defense, and industrial systems. This paper presents a compact W-band dual-channel TWT, utilizing a U-shaped microstrip meander line slow wave structure (SWS). High-frequency characteristics are analyzed through simulation and cold tests. The results demonstrate that adjusting structural parameters effectively optimizes the S-parameters. Particle-in-cell (PIC) simulations with an 18.8 kV, 0.1 A electron beam predict an output power of 18 W with a gain of 14 dB. Experimental measurements of S-parameters are conducted using three substrate materials: Rogers5880 , quartz, and diamond. The quartz substrate exhibits the closest agreement with simulation results. The results advance the development of the microstrip TWTs for high-data-rate communication systems.
Microstrip Traveling Wave Tubes (TWTs) have garnered significant attention due to their potential applications in communication, defense, and industrial systems. This paper presents a compact W-band dual-channel TWT, utilizing a U-shaped microstrip meander line slow wave structure (SWS). High-frequency characteristics are analyzed through simulation and cold tests. The results demonstrate that adjusting structural parameters effectively optimizes the S-parameters. Particle-in-cell (PIC) simulations with an 18.8 kV, 0.1 A electron beam predict an output power of 18 W with a gain of 14 dB. Experimental measurements of S-parameters are conducted using three substrate materials: Rogers
, Available online ,
doi: 10.11884/HPLPB202537.240430
Abstract:
X-ray beam position Monitor (XBPM) can be used to measure the position of synchrotron radiation. The front-end acquisition circuit is mainly used for analog signal acquisition and processing. In this paper, an XBPM electronic analog front-end board (XBPM-AFE) suitable for the front end area of High Energy Photo Source (HEPS) beamline is developed. The functions of current-voltage conversion, range switching, gain control and ADC sampling of the signal of XBPM are designed and implemented. The hardware circuit design and the test results of XBPM-AFE are given.
X-ray beam position Monitor (XBPM) can be used to measure the position of synchrotron radiation. The front-end acquisition circuit is mainly used for analog signal acquisition and processing. In this paper, an XBPM electronic analog front-end board (XBPM-AFE) suitable for the front end area of High Energy Photo Source (HEPS) beamline is developed. The functions of current-voltage conversion, range switching, gain control and ADC sampling of the signal of XBPM are designed and implemented. The hardware circuit design and the test results of XBPM-AFE are given.
, Available online ,
doi: 10.11884/HPLPB202537.250045
Abstract:
In view of the limitations associated with traditional single-spot laser solid-state phase transformation temperature control methods in complex curved workpieces, this paper proposes a Multi-input Multi-output (MIMO) temperature decoupling control strategy based on Active Disturbance Rejection Control (ADRC). Firstly, a finite element model of multi-spot laser-induced solid-state phase transformation was developed, and a model-order reduction method was applied to extract the key dynamic characteristics of the system, significantly reducing computational complexity and laying a foundation for effective control. Subsequently, to address the high-frequency jitter problem encountered by the conventional fal function within small-error regions, an improved bfal function based on Bernstein polynomials was proposed, thereby enhancing system observation accuracy and disturbance rejection capability. Moreover, an improved Particle Swarm Optimization (PSO) algorithm was utilized for the parameter tuning of ADRC controllers, effectively accelerating the optimization process. Finally, co-simulations conducted on the MATLAB/Simulink and COMSOL platforms demonstrated that the proposed PSO-ADRC controller achieves superior performance in terms of response speed, overshoot reduction, and steady-state accuracy compared to the conventional PID and standard ADRC methods. The method thus provides an efficient and precise solution for multi-spot laser solid-state phase transformation temperature control in complex curved workpieces.
In view of the limitations associated with traditional single-spot laser solid-state phase transformation temperature control methods in complex curved workpieces, this paper proposes a Multi-input Multi-output (MIMO) temperature decoupling control strategy based on Active Disturbance Rejection Control (ADRC). Firstly, a finite element model of multi-spot laser-induced solid-state phase transformation was developed, and a model-order reduction method was applied to extract the key dynamic characteristics of the system, significantly reducing computational complexity and laying a foundation for effective control. Subsequently, to address the high-frequency jitter problem encountered by the conventional fal function within small-error regions, an improved bfal function based on Bernstein polynomials was proposed, thereby enhancing system observation accuracy and disturbance rejection capability. Moreover, an improved Particle Swarm Optimization (PSO) algorithm was utilized for the parameter tuning of ADRC controllers, effectively accelerating the optimization process. Finally, co-simulations conducted on the MATLAB/Simulink and COMSOL platforms demonstrated that the proposed PSO-ADRC controller achieves superior performance in terms of response speed, overshoot reduction, and steady-state accuracy compared to the conventional PID and standard ADRC methods. The method thus provides an efficient and precise solution for multi-spot laser solid-state phase transformation temperature control in complex curved workpieces.
, Available online ,
doi: 10.11884/HPLPB202537.250100
Abstract:
This study establishes a thermal radiation pulse transport model to quantify the energy release rate and cumulative energy of thermal radiation across temporal variations, spectral bands, and propagation distances through dimensionless processing and numerical simulations. Special emphasis is placed on analyzing the influence of atmospheric transmittance and air density ratios on the spatial distribution of thermal radiation energy, revealing the propagation characteristics of strong explosion-induced thermal radiation in spatial transmission and its wavelength dependence. The results demonstrate that temporally, the cumulative thermal radiation energy increases with time while exhibiting a gradually decreasing growth rate. During the fireball re-ignition phase, the visible band contributes a marginally higher proportion to cumulative energy, whereas the infrared band dominates during the cooling phase. Spatially, the thermal radiation energy decreases with lower altitude as propagation distance extends, until reaching a stabilization threshold where the spatial distribution becomes relatively constant. The developed model enables prediction of thermal radiation energy distribution at specific locations under arbitrary explosion conditions, providing theoretical support for protective design of wavelength-sensitive materials.
This study establishes a thermal radiation pulse transport model to quantify the energy release rate and cumulative energy of thermal radiation across temporal variations, spectral bands, and propagation distances through dimensionless processing and numerical simulations. Special emphasis is placed on analyzing the influence of atmospheric transmittance and air density ratios on the spatial distribution of thermal radiation energy, revealing the propagation characteristics of strong explosion-induced thermal radiation in spatial transmission and its wavelength dependence. The results demonstrate that temporally, the cumulative thermal radiation energy increases with time while exhibiting a gradually decreasing growth rate. During the fireball re-ignition phase, the visible band contributes a marginally higher proportion to cumulative energy, whereas the infrared band dominates during the cooling phase. Spatially, the thermal radiation energy decreases with lower altitude as propagation distance extends, until reaching a stabilization threshold where the spatial distribution becomes relatively constant. The developed model enables prediction of thermal radiation energy distribution at specific locations under arbitrary explosion conditions, providing theoretical support for protective design of wavelength-sensitive materials.
, Available online ,
doi: 10.11884/HPLPB202537.250027
Abstract:
In order to achieve four-phase images registration, an image registration method based on SIFT (Scale Invariant Features Transform) algorithm is proposed in this paper. The method is divided into four steps. Firstly, the feature points of the reference image and the misregistration images are extracted respectively. In this step, the characteristics of 2D-VISAR images are fully considered and homologous non-fringe images are introduced to obtain more accurate results. The second step is feature points matching. After roughly matching, the two-step-filtering method composed by angle histograms and feature point distance is designed to achieve accurate matching. The third step involves calculating the transformation parameters based on the final matching results. Finally, the transformation parameters are applied to misregistration images for interpolation transformation to achieve image registration. One of the four-phase images is used as the reference image to register the remaining three images. For nonfringe images, experimental results show that the correlation coefficient between registered images and the reference image increases from 0.5 to above 0.9. For fringe images , the calculation accuracy of wrapped phase improves significantly. Therefore, the algorithm in this paper effectively solves the registration problem of 2D-VISAR four-phase images, laying a foundation for further data processing in the future.
In order to achieve four-phase images registration, an image registration method based on SIFT (Scale Invariant Features Transform) algorithm is proposed in this paper. The method is divided into four steps. Firstly, the feature points of the reference image and the misregistration images are extracted respectively. In this step, the characteristics of 2D-VISAR images are fully considered and homologous non-fringe images are introduced to obtain more accurate results. The second step is feature points matching. After roughly matching, the two-step-filtering method composed by angle histograms and feature point distance is designed to achieve accurate matching. The third step involves calculating the transformation parameters based on the final matching results. Finally, the transformation parameters are applied to misregistration images for interpolation transformation to achieve image registration. One of the four-phase images is used as the reference image to register the remaining three images. For nonfringe images, experimental results show that the correlation coefficient between registered images and the reference image increases from 0.5 to above 0.9. For fringe images , the calculation accuracy of wrapped phase improves significantly. Therefore, the algorithm in this paper effectively solves the registration problem of 2D-VISAR four-phase images, laying a foundation for further data processing in the future.
, Available online ,
doi: 10.11884/HPLPB202537.250030
Abstract:
In order to solve the problem of microwave ignition of solid energetic materials under low power conditions, this paper proposes a low-power high-field microwave ignition technology based on dual-focusing optimization design of rectangular resonant cavity. The developed microwave ignition device consists of a solid-state microwave source, a rectangular resonant cavity, a microwave probe and other parts. Among them, the rectangular resonant cavity is fed by a probe, and the energy is focused once by resonance. Combined with the distortion effect of the probe tip on the electric field and the compression effect of the metal stage on the electric field distribution space, the secondary focusing of the energy in the cavity during resonance is realized, and the electromagnetic compatibility design is used to prevent electromagnetic wave leakage. The simulation and experiment show that the microwave ignition device has multiple operating frequency points in the range of 2−3 GHz and the frequency is adjustable. The maximum field strength can reach MV/m level at 22 W power, and can realize the effective ignition of small black powder. Compared with the existing device, the ignition power is greatly reduced. The developed low-power and high-field microwave ignition technology can provide a platform for the study of microwave ignition of solid energetic materials.
In order to solve the problem of microwave ignition of solid energetic materials under low power conditions, this paper proposes a low-power high-field microwave ignition technology based on dual-focusing optimization design of rectangular resonant cavity. The developed microwave ignition device consists of a solid-state microwave source, a rectangular resonant cavity, a microwave probe and other parts. Among them, the rectangular resonant cavity is fed by a probe, and the energy is focused once by resonance. Combined with the distortion effect of the probe tip on the electric field and the compression effect of the metal stage on the electric field distribution space, the secondary focusing of the energy in the cavity during resonance is realized, and the electromagnetic compatibility design is used to prevent electromagnetic wave leakage. The simulation and experiment show that the microwave ignition device has multiple operating frequency points in the range of 2−3 GHz and the frequency is adjustable. The maximum field strength can reach MV/m level at 22 W power, and can realize the effective ignition of small black powder. Compared with the existing device, the ignition power is greatly reduced. The developed low-power and high-field microwave ignition technology can provide a platform for the study of microwave ignition of solid energetic materials.
Design and validation of a proton beam line based on a rapid-cycling synchrotron for Flash radiation
, Available online ,
doi: 10.11884/HPLPB202537.250003
Abstract:
We design a proton beamline based on a rapid-cycling synchrotron for Flash radiation with ultra-high dose rate. Because proton beams can be extracted within hundreds of nanoseconds in the rapid-cycling synchrotron, its energy may be altered from one cycle to the next with different extraction time. The intended beamline system can realize layer stacking irradiation at an instantaneous dose rate of 107 Gy/s. Each of longitudinal layer requires a different beam intensity. The target is divided longitudinally into different layers, each of which needs a different beam energy, in order to produce a uniform irradiation field. The system, including a double scatter system, a range compensator, a ripple filter, and a multi-leaf collimator to maximize proton fluence into the target, is simulated using the Monte Carlo software FLUKA. Three different kinds of ripple filters are built in the low, medium, and high energy zones based on the original Bragg peaks in order to decrease the number of energy layers and shorten the total irradiation duration. These filters transform the spike region into a Gaussian distribution with flat expansion areas of 2 cm, 6 cm, and 20 cm, respectively. Combining the rapid-cycling synchrotron with the layer stacking irradiation provides a novel method for realizing Flash proton irradiation, which delivers an ultra-high dose rate to the target.
We design a proton beamline based on a rapid-cycling synchrotron for Flash radiation with ultra-high dose rate. Because proton beams can be extracted within hundreds of nanoseconds in the rapid-cycling synchrotron, its energy may be altered from one cycle to the next with different extraction time. The intended beamline system can realize layer stacking irradiation at an instantaneous dose rate of 107 Gy/s. Each of longitudinal layer requires a different beam intensity. The target is divided longitudinally into different layers, each of which needs a different beam energy, in order to produce a uniform irradiation field. The system, including a double scatter system, a range compensator, a ripple filter, and a multi-leaf collimator to maximize proton fluence into the target, is simulated using the Monte Carlo software FLUKA. Three different kinds of ripple filters are built in the low, medium, and high energy zones based on the original Bragg peaks in order to decrease the number of energy layers and shorten the total irradiation duration. These filters transform the spike region into a Gaussian distribution with flat expansion areas of 2 cm, 6 cm, and 20 cm, respectively. Combining the rapid-cycling synchrotron with the layer stacking irradiation provides a novel method for realizing Flash proton irradiation, which delivers an ultra-high dose rate to the target.
, Available online ,
doi: 10.11884/HPLPB202537.250062
Abstract:
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Measurement method for areal density of pulsed X-ray photographic images in metal ejection diagnosis
, Available online ,
doi: 10.11884/HPLPB202537.250025
Abstract:
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
, Available online ,
doi: 10.11884/HPLPB202537.250021
Abstract:
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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, Available online ,
doi: 10.11884/HPLPB202537.250072
Abstract:
To achieve stable transmission of laser with lower loss, single mode, and single polarization in the mid-infrared band, This paper designs a bend-resistant hollow-core anti-resonant fiber configuration with a double-cladding nested structure. The finite element method is used to optimize the structural parameters, and the transmission characteristics of broadband low-loss single polarization of the fiber are verified through simulation. The confinement loss of this fiber is less than 0.01 dB/km within the wavelength range of 2.9−3.3 μm, and the high-order mode extinction ratio exceeds1000 , and the confinement loss is as low as 0.0014 dB/km at 3 μm wavelength. The symmetry of the fiber structure is destroyed by using different nested tube thicknesses, and the single-polarization characteristic of the fiber is theoretically investigated. Within the wavelength range of 2.996−3.004 μm, the polarization extinction ratio exceeds 10000 , demonstrating an extremely stable single polarization effect. In addition, theoretical analysis indicates that this fiber also has excellent bending resistance performance. When the bending radius in the y-direction is greater than 5 cm, it can still ensure single-polarization laser transmission, and the bending loss is less than 3.11 dB/km. The designed hollow-core anti-resonant fiber configuration has great potential for application in mid-infrared fiber laser and other fields.
To achieve stable transmission of laser with lower loss, single mode, and single polarization in the mid-infrared band, This paper designs a bend-resistant hollow-core anti-resonant fiber configuration with a double-cladding nested structure. The finite element method is used to optimize the structural parameters, and the transmission characteristics of broadband low-loss single polarization of the fiber are verified through simulation. The confinement loss of this fiber is less than 0.01 dB/km within the wavelength range of 2.9−3.3 μm, and the high-order mode extinction ratio exceeds
, Available online ,
doi: 10.11884/HPLPB202537.250089
Abstract:
This paper proposes a compact Q-band relativistic backward wave oscillator (RBWO) operating at low magnetic fields, aiming to advance the miniaturization of high-power microwave (HPM) sources. The device consists of a resonant cavity reflector and two sections of periodic slow-wave structures (SWS), designed in a coaxial configuration. By exploiting the inherent characteristics of the coaxial structure, an optimal inner diameter was selected to enhance power handling capacity while mitigating space charge effects induced by the reduced device size. Through comprehensive simulation and optimization, the device achieved a microwave output power of 470 MW with an efficiency of 39.1% under operational conditions of a guiding magnetic field (0.9 T), a diode voltage of 400 kV, and a beam current of 3 kA. The generated microwave signal exhibited a central frequency of 45 GHz.
This paper proposes a compact Q-band relativistic backward wave oscillator (RBWO) operating at low magnetic fields, aiming to advance the miniaturization of high-power microwave (HPM) sources. The device consists of a resonant cavity reflector and two sections of periodic slow-wave structures (SWS), designed in a coaxial configuration. By exploiting the inherent characteristics of the coaxial structure, an optimal inner diameter was selected to enhance power handling capacity while mitigating space charge effects induced by the reduced device size. Through comprehensive simulation and optimization, the device achieved a microwave output power of 470 MW with an efficiency of 39.1% under operational conditions of a guiding magnetic field (0.9 T), a diode voltage of 400 kV, and a beam current of 3 kA. The generated microwave signal exhibited a central frequency of 45 GHz.
Display Method:
2025, 37: 061001.
doi: 10.11884/HPLPB202537.250096
Abstract:
Mid-infrared lasers hold significant application demands in fields such as medicine, communications, and national defense. In recent years, research on mid-infrared fiber lasers has attracted extensive attention worldwide. This work demonstrates a high-power mid-infrared light source at 4.16 μm utilizing HBr gas-filled anti-resonant hollow-core fiber (AR-HCF). By employing a homemade 2 μm single-frequency fiber amplifier as the pump source and utilizing the intrinsic absorption of gas molecules to achieve population inversion, we have realized over 10 W continuous wave mid-infrared output through backward gas-filling method in large-mode-area (AR-HCF). This optimized configuration simultaneously enhances the optical-to-optical conversion efficiency and effectively suppresses thermal accumulation limitations. At the maximum incident pump power of 63.8 W, the system achieves a maximum continuous output power of 10.37 W with corresponding slope efficiency of approximately 16.8%. The beam quality measurement reveals M2<1.1 at maximum power operation. This research verifies the substantial capability of fiber gas lasers to generate high-power mid-infrared radiation, providing valuable insights for advancing the development and investigation of mid-infrared fiber laser technologies.
Mid-infrared lasers hold significant application demands in fields such as medicine, communications, and national defense. In recent years, research on mid-infrared fiber lasers has attracted extensive attention worldwide. This work demonstrates a high-power mid-infrared light source at 4.16 μm utilizing HBr gas-filled anti-resonant hollow-core fiber (AR-HCF). By employing a homemade 2 μm single-frequency fiber amplifier as the pump source and utilizing the intrinsic absorption of gas molecules to achieve population inversion, we have realized over 10 W continuous wave mid-infrared output through backward gas-filling method in large-mode-area (AR-HCF). This optimized configuration simultaneously enhances the optical-to-optical conversion efficiency and effectively suppresses thermal accumulation limitations. At the maximum incident pump power of 63.8 W, the system achieves a maximum continuous output power of 10.37 W with corresponding slope efficiency of approximately 16.8%. The beam quality measurement reveals M2<1.1 at maximum power operation. This research verifies the substantial capability of fiber gas lasers to generate high-power mid-infrared radiation, providing valuable insights for advancing the development and investigation of mid-infrared fiber laser technologies.
2025, 37: 061002.
doi: 10.11884/HPLPB202537.250004
Abstract:
Laser wireless energy transmission technology has the advantages of high power, long transmission distance, non-contact operation, and simultaneous energy and information transmission, and is expected to become a revolutionary energy transmission method, showing great application potential in consumer electronics, drones, aerospace and other fields. In this paper, the core module of laser wireless energy transmission technology and its development status in the fields of ground, aerospace and underwater at home and abroad are analyzed, and the technical challenges are summarized. Finally, the future development trend of laser wireless energy transmission system is discussed.
Laser wireless energy transmission technology has the advantages of high power, long transmission distance, non-contact operation, and simultaneous energy and information transmission, and is expected to become a revolutionary energy transmission method, showing great application potential in consumer electronics, drones, aerospace and other fields. In this paper, the core module of laser wireless energy transmission technology and its development status in the fields of ground, aerospace and underwater at home and abroad are analyzed, and the technical challenges are summarized. Finally, the future development trend of laser wireless energy transmission system is discussed.
2025, 37: 061003.
doi: 10.11884/HPLPB202537.240433
Abstract:
The output characteristics of a narrow line width optical parametric oscillator with KTP as the nonlinear crystal pumped by a 532 nm wavelength all-solid-state quasi-continuous-wave Nd:YAG laser are studied. A quartz etalon is inserted into the resonant cavity to compress the output laser line width. Through theoretical analysis, the transmission spectra line width of the etalon for the idler wave within the pulsed optical parametric oscillator’s resonant cavity is estimated. Based on the calculation results, the parameters of the etalon for experimental use are designed. By inserting another KTP crystal into the optical parametric oscillator resonant cavity to perform intracavity frequency doubling on the idler, a tunable yellow laser output with a wavelength tuning range of 574.5-577.2 nm and a pm-level line width is achieved. At a repetition rate of 10 kHz and an average pump power of 30 W, the peak wavelength of the frequency doubled yellow light is 575.81 nm, with a corresponding average output power of 155 mW and a pulse width of about 35 ns. The line width at the peak wavelength is only 0.8 pm, and the beam quality factor in the x and y directions is measured respectively as 1.286 and 1.807.
The output characteristics of a narrow line width optical parametric oscillator with KTP as the nonlinear crystal pumped by a 532 nm wavelength all-solid-state quasi-continuous-wave Nd:YAG laser are studied. A quartz etalon is inserted into the resonant cavity to compress the output laser line width. Through theoretical analysis, the transmission spectra line width of the etalon for the idler wave within the pulsed optical parametric oscillator’s resonant cavity is estimated. Based on the calculation results, the parameters of the etalon for experimental use are designed. By inserting another KTP crystal into the optical parametric oscillator resonant cavity to perform intracavity frequency doubling on the idler, a tunable yellow laser output with a wavelength tuning range of 574.5-577.2 nm and a pm-level line width is achieved. At a repetition rate of 10 kHz and an average pump power of 30 W, the peak wavelength of the frequency doubled yellow light is 575.81 nm, with a corresponding average output power of 155 mW and a pulse width of about 35 ns. The line width at the peak wavelength is only 0.8 pm, and the beam quality factor in the x and y directions is measured respectively as 1.286 and 1.807.
2025, 37: 061004.
doi: 10.11884/HPLPB202537.240444
Abstract:
This paper reports on a room-temperature Yb:YAG rod laser with high power and high beam quality. The oscillator utilizes a moderately doped Yb:YAG rod crystal (Yb3+ 2.0 at atomic fraction of %) and employs quasi-continuous-wave end-pumping. At a repetition rate of 100 Hz, it achieved a 22 W linearly polarized laser output, with a slope efficiency of 53.5% and an optical-to-optical efficiency of 47.4%, while maintaining a beam quality of M2 = 1.22. Using acousto-optic Q-switching, the laser produced a 20.8 W pulse output with an energy of 9.9 mJ and a beam quality of M2 = 1.39, demonstrating the laser's capability for high-repetition-rate Q-switched pulse output.
This paper reports on a room-temperature Yb:YAG rod laser with high power and high beam quality. The oscillator utilizes a moderately doped Yb:YAG rod crystal (Yb3+ 2.0 at atomic fraction of %) and employs quasi-continuous-wave end-pumping. At a repetition rate of 100 Hz, it achieved a 22 W linearly polarized laser output, with a slope efficiency of 53.5% and an optical-to-optical efficiency of 47.4%, while maintaining a beam quality of M2 = 1.22. Using acousto-optic Q-switching, the laser produced a 20.8 W pulse output with an energy of 9.9 mJ and a beam quality of M2 = 1.39, demonstrating the laser's capability for high-repetition-rate Q-switched pulse output.
2025, 37: 061005.
doi: 10.11884/HPLPB202537.240407
Abstract:
This paper conducts a detailed study on the influence of second-harmonic parasitic effects in non-collinear ultra-broadband degenerate optical parametric amplification (OPA), which is pumped by frequency-doubled Ti:sapphire lasers. We considered both walk-off compensation and non-walk-off compensation scenarios. The study reveals that, under the non-walk-off compensation method, by appropriately increasing the non-collinear angle between the pump and signal beams, the impact of second-harmonic parasitic effects on the signal’s output spectrum can be effectively reduced while ensuring broad-spectrum amplification of the signal. The evolution of the signal’s output spectrum and output flux is investigated for different pump spectral bandwidths, clarifying the requirements for the pump spectral bandwidth given a specific signal output spectral bandwidth. The research findings provide design guidelines for generating ultra-broadband, high-temporal contrast femtosecond seed based on degenerate OPA.
This paper conducts a detailed study on the influence of second-harmonic parasitic effects in non-collinear ultra-broadband degenerate optical parametric amplification (OPA), which is pumped by frequency-doubled Ti:sapphire lasers. We considered both walk-off compensation and non-walk-off compensation scenarios. The study reveals that, under the non-walk-off compensation method, by appropriately increasing the non-collinear angle between the pump and signal beams, the impact of second-harmonic parasitic effects on the signal’s output spectrum can be effectively reduced while ensuring broad-spectrum amplification of the signal. The evolution of the signal’s output spectrum and output flux is investigated for different pump spectral bandwidths, clarifying the requirements for the pump spectral bandwidth given a specific signal output spectral bandwidth. The research findings provide design guidelines for generating ultra-broadband, high-temporal contrast femtosecond seed based on degenerate OPA.
2025, 37: 061006.
doi: 10.11884/HPLPB202537.240346
Abstract:
Aiming at the problems of low extraction accuracy and weak anti-interference ability of line structure light centroids in turbid water bodies, this study proposes an improved internal advancement algorithm, which aims to enhance the accuracy and robustness of the extraction of line structure light centroids in complex environments. Firstly, the median filter is used to preprocess the image to suppress the noise, and combined with the eight-neighborhood method to quickly locate the starting point of the light stripe; subsequently, the grayscale neighborhood attribute method is introduced to dynamically estimate the pixel width of the current line of the line structured light, and based on this range, the maximum interclass variance method is applied to adaptively determine the binarized threshold value, which effectively reduces the background interference; finally, the grayscale gravity method is used to calculate the initial centroid in the constrained range of pixel widths and use this as the basis to advance upward and downward to search for the center point of the line structured light. Comparison tests are conducted in various turbid water environments and different structured light patterns. The results show that compared with the original internal advancement algorithm, the root mean square error of the improved algorithm is reduced by 13.33%, and the running speed of the algorithm is increased by 69.07% compared with Steger’s algorithm, thus realizes the balance between accuracy and speed.
Aiming at the problems of low extraction accuracy and weak anti-interference ability of line structure light centroids in turbid water bodies, this study proposes an improved internal advancement algorithm, which aims to enhance the accuracy and robustness of the extraction of line structure light centroids in complex environments. Firstly, the median filter is used to preprocess the image to suppress the noise, and combined with the eight-neighborhood method to quickly locate the starting point of the light stripe; subsequently, the grayscale neighborhood attribute method is introduced to dynamically estimate the pixel width of the current line of the line structured light, and based on this range, the maximum interclass variance method is applied to adaptively determine the binarized threshold value, which effectively reduces the background interference; finally, the grayscale gravity method is used to calculate the initial centroid in the constrained range of pixel widths and use this as the basis to advance upward and downward to search for the center point of the line structured light. Comparison tests are conducted in various turbid water environments and different structured light patterns. The results show that compared with the original internal advancement algorithm, the root mean square error of the improved algorithm is reduced by 13.33%, and the running speed of the algorithm is increased by 69.07% compared with Steger’s algorithm, thus realizes the balance between accuracy and speed.
2025, 37: 061007.
doi: 10.11884/HPLPB202537.240392
Abstract:
The influence of grating height on the diffraction efficiency of SU-8 micron gratings was studied.The diffraction efficiency of gratings with heights of 6-8 μm, 12-16 μm, and 6-30 μm was simulated and analyzed using rigorous coupled wave theory. The simulation results show that when the grating height is 6 μm, the 0th order diffraction efficiency is the lowest and the 1st order diffraction efficiency is the highest; At 12 μm, the 0th order diffraction efficiency is the highest and the 1st order diffraction efficiency is the lowest. When the grating height continuously changes from 6-30 μm, the diffraction efficiency varies periodically. SU-8 thin films with different thicknesses were prepared, and 40 μm periodic gratings with different gate heights were fabricated using picosecond laser etching technology. The measurement results show that when the grating height of the 40 μm period grating is 6.83 μm, the −1st order diffraction efficiency is 28.4%, and the 0th order diffraction efficiency is about 14.7%; When the grating height is 13.45 μm , the 0th order diffraction efficiency is 31.46% and the 1st order diffraction efficiency is 12.35%. The magnitude of the 0th and 1st order diffraction efficiencies varies with the grating height period. The theoretical simulation and experimental exploration can provide important references for the preparation of SU-8 micron gratings and the improvement of first-order diffraction efficiency.
The influence of grating height on the diffraction efficiency of SU-8 micron gratings was studied.The diffraction efficiency of gratings with heights of 6-8 μm, 12-16 μm, and 6-30 μm was simulated and analyzed using rigorous coupled wave theory. The simulation results show that when the grating height is 6 μm, the 0th order diffraction efficiency is the lowest and the 1st order diffraction efficiency is the highest; At 12 μm, the 0th order diffraction efficiency is the highest and the 1st order diffraction efficiency is the lowest. When the grating height continuously changes from 6-30 μm, the diffraction efficiency varies periodically. SU-8 thin films with different thicknesses were prepared, and 40 μm periodic gratings with different gate heights were fabricated using picosecond laser etching technology. The measurement results show that when the grating height of the 40 μm period grating is 6.83 μm, the −1st order diffraction efficiency is 28.4%, and the 0th order diffraction efficiency is about 14.7%; When the grating height is 13.45 μm , the 0th order diffraction efficiency is 31.46% and the 1st order diffraction efficiency is 12.35%. The magnitude of the 0th and 1st order diffraction efficiencies varies with the grating height period. The theoretical simulation and experimental exploration can provide important references for the preparation of SU-8 micron gratings and the improvement of first-order diffraction efficiency.
2025, 37: 063001.
doi: 10.11884/HPLPB202537.240411
Abstract:
To address the wideband and beam scanning requirements of high-power microwave (HPM) systems, this paper proposes an X-band varactor-based high-power wideband beam-scanning reflectarray antenna. The antenna employs a linearly polarized horn feed and a sandwich-structured embedded patch element, where the nested dual-resonance structure integrated with varactors simultaneously extends the phase tuning range (360°) and operational bandwidth. By eliminating abrupt structural discontinuities and adopting a sandwich dielectric configuration, the design effectively suppresses triple-junction formation, achieving a power capacity of 5 MW in 0.1 MPa SF6 environment. Varactor capacitance adjustment enables a 12% relative tuning bandwidth within 8.55−9.65 GHz. Simulations of an 11×11 rectangular grid reflectarray demonstrate a maximum gain of 25.12 dBi with 54.39% aperture efficiency for a 242 mm aperture and full-band 0°−20° beam scanning capability. Compared with existing technologies, this design exhibits superior tuning bandwidth (12%) and power capacity (5 MW), providing an effective solution for wideband beam control in HPM systems.
To address the wideband and beam scanning requirements of high-power microwave (HPM) systems, this paper proposes an X-band varactor-based high-power wideband beam-scanning reflectarray antenna. The antenna employs a linearly polarized horn feed and a sandwich-structured embedded patch element, where the nested dual-resonance structure integrated with varactors simultaneously extends the phase tuning range (360°) and operational bandwidth. By eliminating abrupt structural discontinuities and adopting a sandwich dielectric configuration, the design effectively suppresses triple-junction formation, achieving a power capacity of 5 MW in 0.1 MPa SF6 environment. Varactor capacitance adjustment enables a 12% relative tuning bandwidth within 8.55−9.65 GHz. Simulations of an 11×11 rectangular grid reflectarray demonstrate a maximum gain of 25.12 dBi with 54.39% aperture efficiency for a 242 mm aperture and full-band 0°−20° beam scanning capability. Compared with existing technologies, this design exhibits superior tuning bandwidth (12%) and power capacity (5 MW), providing an effective solution for wideband beam control in HPM systems.
2025, 37: 063002.
doi: 10.11884/HPLPB202537.250028
Abstract:
The signal compensation method based on Wiener filtering has been demonstrated to have excellent compensation performance towards the signal distortion induced by the long-distance transmission in coaxial cable. However, factors affect the compensation performance of this method had not been investigated and analyzed, thus we carried out a systematic study on the effect of the parameters and the means of this modified method. The results show the main factors are the signal-to-noise ratio (SNR), the sampling frequency interval Δf in S21 parameter measurement, and the power spectrum estimation method. When the SNR is less than 25 dB, the compensation performance continuously improves as the SNR increases. Once the SNR exceeds 25 dB, the relative error (δ) between the compensated signal and input signal nearly keeps unchanged. The compensation performance keeps unchanged when Δf is small, and it slowly deteriorates as Δf exceeds a certain value. It is proved that among the traditional power spectrum estimation methods, the Burg method can obtain the best compensation performance. This study can provide a beneficial reference for the application of the signal compensation method based on Wiener filtering.
The signal compensation method based on Wiener filtering has been demonstrated to have excellent compensation performance towards the signal distortion induced by the long-distance transmission in coaxial cable. However, factors affect the compensation performance of this method had not been investigated and analyzed, thus we carried out a systematic study on the effect of the parameters and the means of this modified method. The results show the main factors are the signal-to-noise ratio (SNR), the sampling frequency interval Δf in S21 parameter measurement, and the power spectrum estimation method. When the SNR is less than 25 dB, the compensation performance continuously improves as the SNR increases. Once the SNR exceeds 25 dB, the relative error (δ) between the compensated signal and input signal nearly keeps unchanged. The compensation performance keeps unchanged when Δf is small, and it slowly deteriorates as Δf exceeds a certain value. It is proved that among the traditional power spectrum estimation methods, the Burg method can obtain the best compensation performance. This study can provide a beneficial reference for the application of the signal compensation method based on Wiener filtering.
2025, 37: 063003.
doi: 10.11884/HPLPB202537.240386
Abstract:
During the integration of High Power Microwave (HPM) systems, the docking condition of the microwave source and the transmission-emission subsystem affects the HPM system performance directly. Poor docking conditions may cause radio frequency breakdown at the connection surface, which will result in the reduction of the entire system’s output power. Therefore, diagnosing the docking state of the system is of great engineering significance. For this reason, a non-contact high-power microwave transmission technology is investigated in this paper, and an injection power measurement method is proposed for a Ku-band GW-level HPM system using a conical horn as the feed source. Based on simulation designs, key subassembly of the technology was developed. In addition, the small signal test and power handling capacity assessment of the subassembly were carried out. The experimental outcomes demonstrated that the reflection coefficient was consistently below −26 dB, the coupling coefficient was (−0.31±0.07) dB within the frequency band of (15±0.15) GHz, and the power handling capacity exceeded 900 MW. The experimental and simulation results show that the proposed measurement technology not only has the characteristics of stable coupling coefficient and low test errors, but also can effectively measure the microwave power injected by HPM source through the feed-horn and diagnose the docking state of the HPM system.
During the integration of High Power Microwave (HPM) systems, the docking condition of the microwave source and the transmission-emission subsystem affects the HPM system performance directly. Poor docking conditions may cause radio frequency breakdown at the connection surface, which will result in the reduction of the entire system’s output power. Therefore, diagnosing the docking state of the system is of great engineering significance. For this reason, a non-contact high-power microwave transmission technology is investigated in this paper, and an injection power measurement method is proposed for a Ku-band GW-level HPM system using a conical horn as the feed source. Based on simulation designs, key subassembly of the technology was developed. In addition, the small signal test and power handling capacity assessment of the subassembly were carried out. The experimental outcomes demonstrated that the reflection coefficient was consistently below −26 dB, the coupling coefficient was (−0.31±0.07) dB within the frequency band of (15±0.15) GHz, and the power handling capacity exceeded 900 MW. The experimental and simulation results show that the proposed measurement technology not only has the characteristics of stable coupling coefficient and low test errors, but also can effectively measure the microwave power injected by HPM source through the feed-horn and diagnose the docking state of the HPM system.
2025, 37: 064001.
doi: 10.11884/HPLPB202537.240240
Abstract:
In response to the timing requirements for the commissioning and offline operation of many pre-research equipments at the China Spallation Neutron Source Phase II (CSNS-II), a timing system has been designed and developed independently based on “high-precision timing generator + low-jitter fiber optical transmission link”, which provides accurate triggers for the pre-research equipments in accordance with the physical design requirements. The hardware mainly consists of with cost-effective master boards and terminal boards, which realize strict synchronization and low-jitter transmission. Meanwhile, the master board has the ability to expand the number of output channels by using multimode optical fiber to realize the cascade connection of the hardware boards through high-speed serial transmission links; the upper software adopts adopts the method of “Serial Server + PC soft IOC” to realise the data interaction mechanism between the master board and Experimental Physics and Industrial Control System (EPICS), which can accurately configure the frequency, delay, pulse width and other parameters remotely. The synchronous timing system has been successfully used in the commissioning and operation of key pre-research equipments such as the radio frequency ion source of the CSNS-II, which has been operated stably and reliably for a long period of time. In addition, compared with commercial products, the timing system has the advantages of flexible design, strong anti-interference capability, and high versatility, which can provide a practical technical reference for the design and realisation of timing system for particle accelerator equipment at home and abroad.
In response to the timing requirements for the commissioning and offline operation of many pre-research equipments at the China Spallation Neutron Source Phase II (CSNS-II), a timing system has been designed and developed independently based on “high-precision timing generator + low-jitter fiber optical transmission link”, which provides accurate triggers for the pre-research equipments in accordance with the physical design requirements. The hardware mainly consists of with cost-effective master boards and terminal boards, which realize strict synchronization and low-jitter transmission. Meanwhile, the master board has the ability to expand the number of output channels by using multimode optical fiber to realize the cascade connection of the hardware boards through high-speed serial transmission links; the upper software adopts adopts the method of “Serial Server + PC soft IOC” to realise the data interaction mechanism between the master board and Experimental Physics and Industrial Control System (EPICS), which can accurately configure the frequency, delay, pulse width and other parameters remotely. The synchronous timing system has been successfully used in the commissioning and operation of key pre-research equipments such as the radio frequency ion source of the CSNS-II, which has been operated stably and reliably for a long period of time. In addition, compared with commercial products, the timing system has the advantages of flexible design, strong anti-interference capability, and high versatility, which can provide a practical technical reference for the design and realisation of timing system for particle accelerator equipment at home and abroad.
2025, 37: 064002.
doi: 10.11884/HPLPB202537.240257
Abstract:
To facilitate online replacement and maintenance of solid-state power sources in particle accelerators, a cavity power combiner with online decoupling capability is required. While cavity combiners offer high power capacity, adjustable input coupling has not been achieved online. Therefore, we designed a 650 MHz eight-in-one cavity power combiner with a rotatable decoupling system. By integrating non-contact open-circuit slits at the RF input port and separating the coupling loop from the cavity, we enabled online rotation adjustment of the magnetic coupling loop. This adjustment allows real-time tuning of input coupling according to the operational status of solid-state power sources, facilitating hot-swapping and efficiency optimization. Simulation results demonstrate high synthesis efficiency and minimal power loss, with excellent amplitude consistency between input and output ports (deviations within 0.25 dB). The ability to adjust coupling online enhances RF isolation at input ports, enabling seamless hot-swappable replacement of power amplifier modules and significantly improving maintainability and flexibility.
To facilitate online replacement and maintenance of solid-state power sources in particle accelerators, a cavity power combiner with online decoupling capability is required. While cavity combiners offer high power capacity, adjustable input coupling has not been achieved online. Therefore, we designed a 650 MHz eight-in-one cavity power combiner with a rotatable decoupling system. By integrating non-contact open-circuit slits at the RF input port and separating the coupling loop from the cavity, we enabled online rotation adjustment of the magnetic coupling loop. This adjustment allows real-time tuning of input coupling according to the operational status of solid-state power sources, facilitating hot-swapping and efficiency optimization. Simulation results demonstrate high synthesis efficiency and minimal power loss, with excellent amplitude consistency between input and output ports (deviations within 0.25 dB). The ability to adjust coupling online enhances RF isolation at input ports, enabling seamless hot-swappable replacement of power amplifier modules and significantly improving maintainability and flexibility.
2025, 37: 064003.
doi: 10.11884/HPLPB202537.240271
Abstract:
The ionization profile monitor (IPM) can provide critical beam distribution information required for real-time debugging and stable operation of high-current proton accelerators. The IPM system of the China Spallation Neutron Source (CSNS) Linac adopts a compact structural design. It collects data in ion mode and performs one-dimensional transverse beam distribution measurement through an optical imaging system. However, the honeycomb mesh structure at the electrode plate apertures blocks some ions or electrons from entering the microchannel plate, causing imaging shadows and introducing beam distribution distortion. Offline numerical algorithms must be used for correction. In this paper, partial differential equation (PDE) restoration and machine learning algorithms are used to correct the imaging shadows and beam distribution distortion caused by the honeycomb mesh of the IPM in the CSNS linac. The unsupervised machine learning method DIP (Deep Image Prior) was employed, and the corrected beam size deviates from the theoretical expectation by less than 10%, while maintaining a good signal-to-noise ratio.
The ionization profile monitor (IPM) can provide critical beam distribution information required for real-time debugging and stable operation of high-current proton accelerators. The IPM system of the China Spallation Neutron Source (CSNS) Linac adopts a compact structural design. It collects data in ion mode and performs one-dimensional transverse beam distribution measurement through an optical imaging system. However, the honeycomb mesh structure at the electrode plate apertures blocks some ions or electrons from entering the microchannel plate, causing imaging shadows and introducing beam distribution distortion. Offline numerical algorithms must be used for correction. In this paper, partial differential equation (PDE) restoration and machine learning algorithms are used to correct the imaging shadows and beam distribution distortion caused by the honeycomb mesh of the IPM in the CSNS linac. The unsupervised machine learning method DIP (Deep Image Prior) was employed, and the corrected beam size deviates from the theoretical expectation by less than 10%, while maintaining a good signal-to-noise ratio.
2025, 37: 064004.
doi: 10.11884/HPLPB202537.240299
Abstract:
For a facility using multi-group magnetic cores, its operation stability will be affected by the different working points of the multi-group magnetic cores being reset in parallel. A direct current reset system of the multi-pulse induction cells is developed instead of the original parallel pulsed reset system for a multi-pulse high power Linear Induction Accelerator (LIA) at burst mode. Resetting multi-group magnetic cores one by one is realized by a separate relay switch for every induction cell and constant current sources with periodical output using the direct current reset system, and the problem of inconsistency in working points caused by parallel pulsed reset is effectively resolved. During engineering implementation, the system operates with two sets of constant current sources and eight switch control boxes to reset 94 groups of induction cell magnetic cores, significantly reducing system complexity and maintenance costs. Practical validation demonstrates that the improved accelerator exhibits enhanced multi-pulse stability, with beam centroid position jitter reduced from 1.3 mm to less than 1 mm. This paper describes the physical design of the direct current reset unit, introduces the layout of the whole reset system which includes the main units, and presents the improvement effect.
For a facility using multi-group magnetic cores, its operation stability will be affected by the different working points of the multi-group magnetic cores being reset in parallel. A direct current reset system of the multi-pulse induction cells is developed instead of the original parallel pulsed reset system for a multi-pulse high power Linear Induction Accelerator (LIA) at burst mode. Resetting multi-group magnetic cores one by one is realized by a separate relay switch for every induction cell and constant current sources with periodical output using the direct current reset system, and the problem of inconsistency in working points caused by parallel pulsed reset is effectively resolved. During engineering implementation, the system operates with two sets of constant current sources and eight switch control boxes to reset 94 groups of induction cell magnetic cores, significantly reducing system complexity and maintenance costs. Practical validation demonstrates that the improved accelerator exhibits enhanced multi-pulse stability, with beam centroid position jitter reduced from 1.3 mm to less than 1 mm. This paper describes the physical design of the direct current reset unit, introduces the layout of the whole reset system which includes the main units, and presents the improvement effect.
2025, 37: 065001.
doi: 10.11884/HPLPB202537.240383
Abstract:
The insulating property of water medium affects the operation state of pulse power device, and air bubbles in water are the main factor causing breakdown of water medium. To remove air bubbles and dissolved gases in the water medium, we analyzed the causes of air bubbles in the water medium. For the removal of body-phase air bubbles and surface adsorption air bubbles in the water medium, we compared the methods of removing air bubbles using vortex separators and reverse osmosis membranes, and we have carried out experimental research to study the performance of these two methods. The results show that the vortex separator’s low cyclonic strength leads to low separation (which can remove the gas bubbles and dissolved gases in the water) efficiency, and the reverse osmosis membrane degassing makes the surface adsorbed bubbles re-dissolve by reducing the solubility of the gas in the water, and the separation efficiency is high. This study is of great significance for the stable operation of the pulsed power device.
The insulating property of water medium affects the operation state of pulse power device, and air bubbles in water are the main factor causing breakdown of water medium. To remove air bubbles and dissolved gases in the water medium, we analyzed the causes of air bubbles in the water medium. For the removal of body-phase air bubbles and surface adsorption air bubbles in the water medium, we compared the methods of removing air bubbles using vortex separators and reverse osmosis membranes, and we have carried out experimental research to study the performance of these two methods. The results show that the vortex separator’s low cyclonic strength leads to low separation (which can remove the gas bubbles and dissolved gases in the water) efficiency, and the reverse osmosis membrane degassing makes the surface adsorbed bubbles re-dissolve by reducing the solubility of the gas in the water, and the separation efficiency is high. This study is of great significance for the stable operation of the pulsed power device.
2025, 37: 065002.
doi: 10.11884/HPLPB202537.240412
Abstract:
With the continuous development of photoconductive microwave technology towards high-frequency, high-power, long-life, and high-efficiency directions, lateral photoconductive devices have the potential to achieve high photoelectric gain and high main frequency response due to intrinsic light triggering and low parasitic capacitance. We investigated the photocurrent response of intrinsic light back-illuminated lateral silicon carbide (SiC) photoconductive switches. Based on semiconductor numerical simulation, the output photocurrent of the device under intrinsic light triggering with different substrate thicknesses and different light powers was compared for front and back illumination. The internal current and electric field distribution of the device were analyzed and compared. Finally, experimental tests were conducted on the front and back triggering of a 50 μm lateral SiC photoconductive switch. The experimental results show that under a 40 kW peak light power, the on-resistance of the back-triggered device is reduced by 40% compared to the front-triggered device, confirming the high photoelectric conversion efficiency of the back-illuminated device, and the internal electric field and current of the back-triggered device are more uniform, which is more conducive to improving the device’s high-power capacity. The results provide simulation and experimental references for the intrinsic triggering of planar photoconductive switches.
With the continuous development of photoconductive microwave technology towards high-frequency, high-power, long-life, and high-efficiency directions, lateral photoconductive devices have the potential to achieve high photoelectric gain and high main frequency response due to intrinsic light triggering and low parasitic capacitance. We investigated the photocurrent response of intrinsic light back-illuminated lateral silicon carbide (SiC) photoconductive switches. Based on semiconductor numerical simulation, the output photocurrent of the device under intrinsic light triggering with different substrate thicknesses and different light powers was compared for front and back illumination. The internal current and electric field distribution of the device were analyzed and compared. Finally, experimental tests were conducted on the front and back triggering of a 50 μm lateral SiC photoconductive switch. The experimental results show that under a 40 kW peak light power, the on-resistance of the back-triggered device is reduced by 40% compared to the front-triggered device, confirming the high photoelectric conversion efficiency of the back-illuminated device, and the internal electric field and current of the back-triggered device are more uniform, which is more conducive to improving the device’s high-power capacity. The results provide simulation and experimental references for the intrinsic triggering of planar photoconductive switches.
2025, 37: 065003.
doi: 10.11884/HPLPB202537.240186
Abstract:
When the photoconductive switch operates continuously under the working conditions of long pulse width and high repetition frequency, due to the existence of a certain conduction resistance, the thermal deposition phenomenon inside the switch is relatively serious, which is likely to cause thermal damage and thermal breakdown of the photoconductive switch, seriously affecting its service life. Therefore, it is necessary to effectively dissipate heat from the high-power photoconductive switch. The conventional cooling circulation system uses the method of pumping out by a circulation pump to cool the object. There are problems such as very high or low pressure of the cooling medium during the circulation process, resulting in uneven cooling of the object, which is extremely likely to cause damage to the object. In addition, the impeller of the circulation pump will generate bubbles during the circulation process, reducing the insulation strength of the photoconductive switch and leading to flashover breakdown along the surface. To address these issues, we have developed a cooling system that eliminates bubbles based on the negative pressure suction mechanism and achieves precise temperature control through a dual-loop system. This system has achieved good heat dissipation for the photoconductive switch. Under the conditions of a working voltage of 11 kV, an output current of 560 A, a pulse width of 55 ns, and a repetition frequency of 1 kHz, the service life of the photoconductive switch has reached 106 times, which is significantly increased.
When the photoconductive switch operates continuously under the working conditions of long pulse width and high repetition frequency, due to the existence of a certain conduction resistance, the thermal deposition phenomenon inside the switch is relatively serious, which is likely to cause thermal damage and thermal breakdown of the photoconductive switch, seriously affecting its service life. Therefore, it is necessary to effectively dissipate heat from the high-power photoconductive switch. The conventional cooling circulation system uses the method of pumping out by a circulation pump to cool the object. There are problems such as very high or low pressure of the cooling medium during the circulation process, resulting in uneven cooling of the object, which is extremely likely to cause damage to the object. In addition, the impeller of the circulation pump will generate bubbles during the circulation process, reducing the insulation strength of the photoconductive switch and leading to flashover breakdown along the surface. To address these issues, we have developed a cooling system that eliminates bubbles based on the negative pressure suction mechanism and achieves precise temperature control through a dual-loop system. This system has achieved good heat dissipation for the photoconductive switch. Under the conditions of a working voltage of 11 kV, an output current of 560 A, a pulse width of 55 ns, and a repetition frequency of 1 kHz, the service life of the photoconductive switch has reached 106 times, which is significantly increased.
2025, 37: 065004.
doi: 10.11884/HPLPB202537.240426
Abstract:
This study focuses on the performance of vertical photoconductive semiconductor switch (PCSS) based on Fe: β-Ga2O3 under high voltage. The results show that deep levels in Fe: β-Ga2O3 can provide carriers of non-intrinsic excitation. The device did not exhibit breakdown tendencies when subjected to a 20 kV input voltage with single-shot laser triggering. After more than5000 trigger cycles at 15 kV by a 10 Hz laser, the switch eventually failed. Nevertheless, pulse performance remained stable throughout the effective data collection period, preliminarily demonstrating the potential of Ga2O3 PCSS for applications in extreme conditions such as high power and high frequency. Failure analysis indicates that a wide bandgap is not the sole determinant of high breakdown voltage. In addition to employing precise doping techniques to introduce specific defects and modify material properties, further improvements in existing material growth methods and device packaging structures can also contribute to enhancing the output and lifetime of PCSS.
This study focuses on the performance of vertical photoconductive semiconductor switch (PCSS) based on Fe: β-Ga2O3 under high voltage. The results show that deep levels in Fe: β-Ga2O3 can provide carriers of non-intrinsic excitation. The device did not exhibit breakdown tendencies when subjected to a 20 kV input voltage with single-shot laser triggering. After more than
2025, 37: 066001.
doi: 10.11884/HPLPB202537.250011
Abstract:
The geoelectric fields induced by late-time high altitude electromagnetic pulse (HEMP E3) and geomagnetic storms lead to low frequency geomagnetically induced currents in the transmission grids, and the resulting half-cycle saturation of a large number of transformers could potentially threaten the power system voltage stability. However, in the existing study on HEMP E3 effect evaluation, it typically assumes a uniform or 1D layered earth structure, without adequately considering the influence of lateral variations in earth conductivity on the induced geoelectric fields. Thus, it is difficult to rigorously assess the electromagnetic security of power systems under complex geological conditions such as coasts. This paper establishes a 3D computational model for HEMP E3 geoelectric fields based on finite element method, then studies the influence of complex earth conductivity structure on the spatiotemporal distribution of HEMP E3 geoelectric fields, and finally evaluates the power system voltage stability via electromagnetic transient simulation method. The results uncover substantial changes in the amplitude and duration of HEMP E3 geoelectric fields near the conductivity interface, which may lead to significant deviation in the voltage stability results of the power system. The method developed in this paper provides an important basis for the HEMP effect evaluation and protection of infrastructure located in complex geological areas.
The geoelectric fields induced by late-time high altitude electromagnetic pulse (HEMP E3) and geomagnetic storms lead to low frequency geomagnetically induced currents in the transmission grids, and the resulting half-cycle saturation of a large number of transformers could potentially threaten the power system voltage stability. However, in the existing study on HEMP E3 effect evaluation, it typically assumes a uniform or 1D layered earth structure, without adequately considering the influence of lateral variations in earth conductivity on the induced geoelectric fields. Thus, it is difficult to rigorously assess the electromagnetic security of power systems under complex geological conditions such as coasts. This paper establishes a 3D computational model for HEMP E3 geoelectric fields based on finite element method, then studies the influence of complex earth conductivity structure on the spatiotemporal distribution of HEMP E3 geoelectric fields, and finally evaluates the power system voltage stability via electromagnetic transient simulation method. The results uncover substantial changes in the amplitude and duration of HEMP E3 geoelectric fields near the conductivity interface, which may lead to significant deviation in the voltage stability results of the power system. The method developed in this paper provides an important basis for the HEMP effect evaluation and protection of infrastructure located in complex geological areas.
2025, 37: 066002.
doi: 10.11884/HPLPB202537.240408
Abstract:
In a surface nuclear leakage scenario, radiation neutrons undergo multiple scatterings with atomic nuclei in the material, rapidly reducing their energy to the thermal neutron range (a few eV). The activation of thermal neutrons significantly impacts the nuclear reaction process. In solid and liquid materials, nuclei typically exist in bound states, differing from free nuclei in gaseous form regarding their interaction with matter. To accurately assess nuclear radiation effects, we investigated the impact of bound-nucleus effects on thermal neutron activation. Using the Monte Carlo method for particle transport simulation, we developed an air-ground interface model based on surface nuclear radiation scenarios. We modeled neutron beam interactions with soil, seawater, and concrete, focusing on thermal neutron activation reactions. By incorporating bound-nucleus effects through adjusted reaction cross-sections, we calculated and compared changes in secondary gamma flux before and after considering these effects. The results show that accounting for bound-nucleus effects enhances thermal neutron activation in solid and liquid media, thereby increasing surface secondary gamma field intensity. Due to factors such as elemental composition and particle shielding, the maximum increases in secondary gamma flux were 18%, 8%, and 11% for the three media, with varying patterns of flux increase over detection distances.
In a surface nuclear leakage scenario, radiation neutrons undergo multiple scatterings with atomic nuclei in the material, rapidly reducing their energy to the thermal neutron range (a few eV). The activation of thermal neutrons significantly impacts the nuclear reaction process. In solid and liquid materials, nuclei typically exist in bound states, differing from free nuclei in gaseous form regarding their interaction with matter. To accurately assess nuclear radiation effects, we investigated the impact of bound-nucleus effects on thermal neutron activation. Using the Monte Carlo method for particle transport simulation, we developed an air-ground interface model based on surface nuclear radiation scenarios. We modeled neutron beam interactions with soil, seawater, and concrete, focusing on thermal neutron activation reactions. By incorporating bound-nucleus effects through adjusted reaction cross-sections, we calculated and compared changes in secondary gamma flux before and after considering these effects. The results show that accounting for bound-nucleus effects enhances thermal neutron activation in solid and liquid media, thereby increasing surface secondary gamma field intensity. Due to factors such as elemental composition and particle shielding, the maximum increases in secondary gamma flux were 18%, 8%, and 11% for the three media, with varying patterns of flux increase over detection distances.
2025, 37: 069001.
doi: 10.11884/HPLPB202537.250001
Abstract:
Terahertz waves, spanning the millimeter and submillimeter wavelength ranges between the microwave and far-infrared regions (approximately 3 mm to 30 μm), represent a critical spectral range in astrophysical and cosmological research. Of the photons detectable since the beginning of the universe, approximately 98% fall within the terahertz and far-infrared bands. A significant proportion of these photons originate from the cosmic microwave background radiation, while others arise from excited molecules that exhibit bright spectral emissions in the terahertz range. As a result, terahertz-based astronomical observation techniques are becoming increasingly essential for investigating the universe’s fundamental properties. Through the observation of interstellar atoms, molecules, and dust, terahertz astronomy provides valuable insights into the internal conditions of the interstellar medium and offers a unique observational window into the formation and evolution of stars, planets, galaxies, and the universe itself. In recent years, many large astronomical telescopes have begun incorporating terahertz detectors based on microwave kinetic inductance detector (MKID), positioning MKID as a pivotal technology in the field of terahertz astronomical detection. This paper outlines the fundamental principles of MKID, reviews recent advancements in the application of MKIDs to terahertz detection, and discusses future developments in this promising area of research.
Terahertz waves, spanning the millimeter and submillimeter wavelength ranges between the microwave and far-infrared regions (approximately 3 mm to 30 μm), represent a critical spectral range in astrophysical and cosmological research. Of the photons detectable since the beginning of the universe, approximately 98% fall within the terahertz and far-infrared bands. A significant proportion of these photons originate from the cosmic microwave background radiation, while others arise from excited molecules that exhibit bright spectral emissions in the terahertz range. As a result, terahertz-based astronomical observation techniques are becoming increasingly essential for investigating the universe’s fundamental properties. Through the observation of interstellar atoms, molecules, and dust, terahertz astronomy provides valuable insights into the internal conditions of the interstellar medium and offers a unique observational window into the formation and evolution of stars, planets, galaxies, and the universe itself. In recent years, many large astronomical telescopes have begun incorporating terahertz detectors based on microwave kinetic inductance detector (MKID), positioning MKID as a pivotal technology in the field of terahertz astronomical detection. This paper outlines the fundamental principles of MKID, reviews recent advancements in the application of MKIDs to terahertz detection, and discusses future developments in this promising area of research.
2025, 37: 069002.
doi: 10.11884/HPLPB202537.240360
Abstract:
A simple and effective improved A* algorithm is proposed to solve the problem of robot path planning in the integrated installation of large-scale laser devices. Compared with the traditional A* algorithm, the algorithm has been improved in three steps. Firstly, the walking direction is limited, which avoids the phenomenon of crossing obstacles occurred in the traditional A* algorithm; Secondly, the heuristic function is optimized as a weighted Manhattan distance function, which accelerates the expansion of nodes in the x direction or y direction, and reduces the surge of traversal nodes caused by limiting the walking direction. Thirdly, the turning penalty term is introduced to reduce the number of turns in the path planning process, and improve the search efficiency and quality. The performance of the three-step improved A* algorithm is verified in different size raster maps, and compared with the traditional A* algorithm. Experimental results show that in simple maps, the number of nodes traversed by the three-step improved A* algorithm is slightly higher than that of the traditional A* algorithm, and the number of turns is equivalent to that of the traditional A* algorithm, but the obstacle avoidance performance is obviously better than that of the traditional A* algorithm, which is more conducive to the safe walking of robots. In complex maps, considering the priority relationship of traversal nodes, turn times and path length, the parameters of the three-step improved A* algorithm can be adjusted to obtain the optimal path planning result.
A simple and effective improved A* algorithm is proposed to solve the problem of robot path planning in the integrated installation of large-scale laser devices. Compared with the traditional A* algorithm, the algorithm has been improved in three steps. Firstly, the walking direction is limited, which avoids the phenomenon of crossing obstacles occurred in the traditional A* algorithm; Secondly, the heuristic function is optimized as a weighted Manhattan distance function, which accelerates the expansion of nodes in the x direction or y direction, and reduces the surge of traversal nodes caused by limiting the walking direction. Thirdly, the turning penalty term is introduced to reduce the number of turns in the path planning process, and improve the search efficiency and quality. The performance of the three-step improved A* algorithm is verified in different size raster maps, and compared with the traditional A* algorithm. Experimental results show that in simple maps, the number of nodes traversed by the three-step improved A* algorithm is slightly higher than that of the traditional A* algorithm, and the number of turns is equivalent to that of the traditional A* algorithm, but the obstacle avoidance performance is obviously better than that of the traditional A* algorithm, which is more conducive to the safe walking of robots. In complex maps, considering the priority relationship of traversal nodes, turn times and path length, the parameters of the three-step improved A* algorithm can be adjusted to obtain the optimal path planning result.
2025, 37: 069003.
doi: 10.11884/HPLPB202537.240229
Abstract:
To optimize the performance of the pulsed xenon lamp sterilization device, the influence of spectral range and specifications of lamps on the sterilization effect is studied based on a self-developed high-energy microsecond pulse power supply and xenon lamps with different specifications. The results show that in the UV-visible spectrum of a xenon lamp with an arc length of 50 mm and a pressure of 50 kPa, the UV accounts for 38.5% and the UVC accounts for 17.6%. Increasing the arc length and decreasing the pressure can both increase the spectral intensity, and the latter can also increase the ratio of UV. The xenon lamp with an arc length of 100 mm and a pressure of 50 kPa can basically inactivate all Escherichia coli in 3 s with a discharge energy of 20 J. The sterilization rate is positively correlated with arc length and discharge energy of the lamp, negatively correlated with pressure. All bands of xenon lamp radiation have sterilization effects, with UV accounting for 87.7% in log value and the wavelength band less than 280 nm accounting for 64.6%. The AFM images show that pulsed xenon lamp changed the morphology and mechanical properties of Escherichia coli, hence the bacteria shrank, their surface roughness, elasticity, and adhesion increased.
To optimize the performance of the pulsed xenon lamp sterilization device, the influence of spectral range and specifications of lamps on the sterilization effect is studied based on a self-developed high-energy microsecond pulse power supply and xenon lamps with different specifications. The results show that in the UV-visible spectrum of a xenon lamp with an arc length of 50 mm and a pressure of 50 kPa, the UV accounts for 38.5% and the UVC accounts for 17.6%. Increasing the arc length and decreasing the pressure can both increase the spectral intensity, and the latter can also increase the ratio of UV. The xenon lamp with an arc length of 100 mm and a pressure of 50 kPa can basically inactivate all Escherichia coli in 3 s with a discharge energy of 20 J. The sterilization rate is positively correlated with arc length and discharge energy of the lamp, negatively correlated with pressure. All bands of xenon lamp radiation have sterilization effects, with UV accounting for 87.7% in log value and the wavelength band less than 280 nm accounting for 64.6%. The AFM images show that pulsed xenon lamp changed the morphology and mechanical properties of Escherichia coli, hence the bacteria shrank, their surface roughness, elasticity, and adhesion increased.
