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Just Accepted manuscripts are peer-reviewed and accepted for publication. They are posted online prior to technical editing formatting for publication and author proofing.
Display Method:
, Available online ,
doi: 10.11884/HPLPB202537.250277
Abstract:
Background Purpose Methods Results Conclusions
Human-represented biological intelligence is transplantable into general intelligence across four levels, namely data intelligence, perceptual intelligence, cognitive intelligence, and autonomous intelligence. As intelligent unmanned technologies advance, electronic systems undergo evolution toward higher intelligence and autonomy; concurrently, bionic electromagnetic protection—an approach that enhances compatibility, adaptability, and threat resistance—evolves in tandem with these electronic systems. Nevertheless, significant gaps persist in the translation of biological mechanisms into practical applications for electronic systems.
Focused on drones as the research subject, this study explores the implementation of biomimetic mapping for drone electromagnetic protection across the aforementioned four levels, with the exploration grounded in core drone performances including communication, navigation, detection, and control. The primary objective of this study is to advance the development of electromagnetic protection toward higher levels of intelligence.
Guided by fundamental design principles of structure-function integration and multi-level immune protection, the research categorizes biomimetic mapping into information and signal levels: the information level encompasses spectrum sensing and autonomous decision-making, while the signal level concentrates on limiting and filtering technologies. For key drone systems, an intelligent data link was designed using software-defined radio technology; navigation receivers were optimized through the integration of shielding, filtering, and anti-interference antennas; a GAN-based image self-repair algorithm incorporating hybrid attention was proposed; and the application of neuromorphic circuits and bionic structures for control systems was explored.
The study successfully developed a spectrum-sensing adaptive data link and a reinforced navigation receiver, and verified the initial realization of perceptual intelligence in selected system components.
Biomimetic mapping contributes to the enhancement of drone electromagnetic protection; however, challenges remain, including the refinement of mapping methods, the development of novel devices, and the advancement of intelligent computing. Future research efforts directed at addressing these challenges will facilitate the full realization of autonomous intelligence in drone electromagnetic protection systems.
, Available online ,
doi: 10.11884/HPLPB202537.250023
Abstract:
Background Purpose Method Result Conclusions
Shenzhen Superconducting Soft X-Ray Free Electron Laser (S3FEL) is newly proposed by Institute of Advanced Science Facilities, Shenzhen (IASF). The linear accelerator based on TESLA-type superconducting RF cavity is used to obtain high-repetition-frequency and high-gradient field. The cryomodule is the most challenging core part in S3FEL device and ultra-high vacuum differential system is located at the module beam pipe outlet, which is used to realize the transition from cryomodule to ambient temperature section. The vacuum interlock protection is required on differential system to protect the superconducting RF cavity in cryomodule from emergency.
This study aims to analyze the transient process of quick protection.
Traditional fast closing valve protection process is only calculated according to gas molecular rate, and the finite element method and the Monte Carlo method are used in this paper.
The transient pressure distribution results of sensor-fast closing valve section show that setting the sensor 8-10 m away from the fast closing valve can provide sufficient buffer reaction time.
The differential system analyses show that the pressure here reaches 1E-5 Pa within 2 s when the gate valve is completely closed, corresponding to leakage sizes of 0.5 mm, which still maintains a high-vacuum environment and meets working requirement of ion pumps. This work provides important theory basis for the S3FEL.
, Available online ,
doi: 10.11884/HPLPB202537.250210
Abstract:
Background Purpose Methods Results Conclusions
In recent years, the development of wound-type mica paper capacitors has significantly enhanced their operating voltage and energy density, and they remain highly reliable, showing potential for improving the overall energy storage density of PFN (pulse forming line)-Marx generators.
The lifetime of the capacitor is a crucial factor in ensuring system reliability. The lifetime of the mica paper capacitor reaches up to 100,000 times, meeting the requirements of highly compact pulse power drivers. However, the lifetime characteristics of this capacitor remain unclear, and its optimal operating conditions have not been well-defined.
In this paper, an investigation into the lifetime characteristics of mica paper capacitors under microsecond pulses is presented. First, the structure of the capacitor is analyzed in detail. Subsequently, numerical simulations of the electrical and thermal fields are carried out to further study its characteristics. To accurately test the mica paper capacitors, a lifetime test platform that can operate stably over an extended period was constructed.
Through the utilization of this platform, the electrical degradation parameters and the failure mechanisms of the mica paper capacitors are obtained and analyzed. Based on the test data, the lifetime empirical model of mica capacitors under given operating conditions is modified.
The results of the experiments and calculations of the lifetime empirical model indicate that the model aligns well with the experimental results. This work contributes to the lifetime prediction of mica capacitor and provides design reference for system devices using mica capacitor under microsecond pulses.
, Available online ,
doi: 10.11884/HPLPB202537.250259
Abstract:
Background Purpose Methods Results Conclusions
The increasing electromagnetic radiation poses a serious hazard to electronic devices, human health, and the environment. Carbon-based materials derived from biomass are considered to have excellent electromagnetic absorption potential due to their high porosity, low density, strong dielectric loss, wide range of sources and low cost.
This study aims to analyze the electromagnetic wave absorption characteristics of biomass-derived carbon-based materials.
This study is based on hydrothermal and carbonization processes, using loofah as the carbon precursor, and introducing NiCo2O4 magnetic particles to prepare NiCo2O4/C (NCO) electromagnetic wave absorbing material, with its actual wave-absorbing performance verified through COMSOL simulation software.
The introduction of NiCo2O4 particles not only enhanced the magnetic loss properties of the composites, but also regulated the dielectric properties and optimized the impedance matching. Due to the unique mesh structure and the synergistic effect of interfacial polarization, conductive loss, magnetic loss and other loss mechanisms, the NiCo2O4/C composites obtain good electromagnetic wave absorption properties, with the strongest reflection loss of −47.46 dB, and the widest absorption band of 5.68 GHz (12−17.68 GHz), which covers almost the whole Ku-band. In addition, the study also demonstrated that NCO-2 composites have some practical applications through RCS simulations.
The synergistic effect of dielectric and magnetic properties can significantly modulate the dielectric properties of composites, optimize impedance matching, and enhance loss mechanisms, thereby achieving excellent electromagnetic wave absorption performance. The work provides a theoretical and experimental basis for the development of green and sustainable high-performance biomass-derived carbon-based composites.
Study of field distribution characteristics of large split EMP simulator with distributed terminator
, Available online ,
doi: 10.11884/HPLPB202537.250080
Abstract:
Background Purpose Methods Results Conclusions
There is currently little research on the choice of the effective work-space of large split vertically polarized electromagnetic pulse (EMP) simulator with distributed terminator.
In order to get the distribution characteristics of the peak-value of electric field’s vertical component (called “field peak-value”) inside large simulators,
two typical planes were chosen as testing-planes found on an example of selecting the effective working-space of this type of simulator firstly, then the influences of the maximum width, the maximum height, and the maximum width of the upper plate’s void on (normalized) field peak-value distribution characteristics on the two testing-planes, are studied and analyzed based on parallel finite-difference time-domain (FDTD) method.
The results show that, field peak-values increase on the two testing-planes, as the simulator’s maximum width is wider, maximum height is lower, and maximum width of the upper plate’s void is smaller. The field peak-value uniform along the simulator’s width direction becomes better as the simulator’s maximum width increases; The field peak-value uniform along the simulator’s height direction becomes better, but becomes slightly wrong along the simulator’s width direction, as the simulator’s maximum height increases; The field peak-value uniform along the simulator’s width direction becomes better, but becomes wrong along the simulator’s height direction, as the maximum width of the upper plate’s void increases.
When selecting an effective workspace in practical experiments, it is necessary to select the appropriate size-parameters of the simulator according to the field peak-values required by the effect experiment and the actual size of the effector, combined with the engineering practice.
, Available online ,
doi: 10.11884/HPLPB202537.250119
Abstract:
Background Purpose Methods Results Conclusions
Many traditional electromagnetic protection materials are limited by fixed protection parameters, preventing the passage of both weak electromagnetic information and strong signals from malicious attacks. This cannot meet the current adaptive requirements for electromagnetic protection of high-frequency equipment in the information age. Hence, it is crucial to explore and create a novel self-adaptive and proactive electromagnetic shielding material. ZnO and graphene composites have attracted attention due to their tunable electrical properties and potential for intelligent protection applications.
This study aims to synthesize and characterize ZnO-coated graphene nanocomposites, with a focus on their nonlinear conductive performance for use in adaptive electromagnetic protection. The goal is to achieve tunable switching behavior through compositional adjustment and microstructural control.
The nanocomposites were synthesized using a solvothermal method. The morphology and distribution of ZnO nanoparticles on graphene were characterized by scanning electron microscopy (SEM). The electrical properties, including nonlinear coefficient and switching thresholds, were measured under varying electric fields.
SEM analysis confirmed the uniform coating of ZnO nanoparticles on graphene sheets. The composites exhibited reversible insulating-conductive transition behavior, with threshold electric fields ranging from 0.19 to 0.53 kV/mm and nonlinear coefficients between 4.01 and 5.44 within the 5–8 wt% mass fraction range. The switching threshold was effectively modulated by adjusting the composite concentration.
The GN/ZnO nanocomposites demonstrate promising adaptive performance with tunable switching characteristics, making them suitable for intelligent electromagnetic protection devices. This study provides a foundation for the design of advanced composite materials for electronic protection systems.
, Available online ,
doi: 10.11884/HPLPB202537.250274
Abstract:
Background Purpose Methods Results Conclusions
The development of drone swarms and the low-altitude economy has highlighted the strategic importance of high-power microwave attack and defense technologies.
This study aims to analyze the time-frequency response characteristics of drone navigation antennas and data link antennas under HPM irradiation.
A three-dimensional electromagnetic coupling model was constructed based on COMSOL, and field-circuit co-simulation was employed to investigate the antennas’ responses to HPM exposure across different polarization types and frequency bands.
The results show that the navigation antenna, equivalent to a narrowband phase-shifting network, exhibits waveform distortions such as rising-edge broadening and falling-edge “truncation” under in-band and adjacent broadband pulse excitation due to strong dispersion. In contrast, the data link antenna maintains waveform integrity under various excitations owing to its flat amplitude-frequency and phase-frequency responses with weak dispersion. In the frequency domain, both antennas exhibit maximum coupled voltage at frequencies offset from the center, while the peak power occurs at the center frequency. The navigation antenna responds most strongly to right-hand circular polarization but shows enhanced left-hand coupling at frequency offsets. The data link antenna demonstrates similar responses to all polarizations, indicating polarization insensitivity.
The polarization type and frequency selectivity of antennas dominate the HPM coupling process through intrinsic dispersion mechanisms, determining energy response and waveform integrity. A multi-level protection system incorporating “front-end filtering—transient suppression—system redundancy” is recommended to enhance the electromagnetic resilience of drones. This study provides theoretical support for the countermeasures and protection of drones.
, Available online ,
doi: 10.11884/HPLPB202537.250192
Abstract:
Background Purpose Methods Results Conclusions
As an important part of klystrons, the characteristics of the resonant cavity have a decisive influence on the performance of klystrons. In the field of high-band klystrons, due to the limitation of processing technology and welding technology, the integrally processed rectangular resonant cavity is mostly used.
The traditional integrally processed rectangular resonant cavity is prone to problems such as frequency deviation of the resonant cavity or even inoperability of the resonant cavity when frequency adjustment is performed.
Accordingly, this paper innovatively proposes a practical new frequency-modulation structure: a coupling diaphragm with slots cut into the resonator cavity walls and openings added.
Simulation calculations validate that when this structure is applied to the rectangular resonant cavity, a large-scale frequency adjustment can be achieved, effectively compensating for the frequency deviation caused by the machining tolerance of parts.
During frequency tuning, applying external force deforms the diaphragm to increase cavity frequency, while enlarging the coupling aperture on the diaphragm lowers it. Moreover, the frequency adjustment operation becomes simple and rapid, significantly improving the research and development efficiency of the klystron, thus providing a new technical approach for the optimization and development of high-band klystrons.
, Available online ,
doi: 10.11884/HPLPB202537.250038
Abstract:
Background Purpose Methods Results Conclusions
To enhance the performance of the next-generation X-ray free electron laser (XFEL), a photocathode RF gun capable of providing the required high-quality electron beam with a small emittance has been a significant research objective. In comparison to the conventional L-band or S-band RF gun, the C-band RF gun features a higher acceleration gradient above 150 MV/m and the ability to generate a small-emittance beam. Low-emittance electron beams are critical for enhancing XFEL coherence and brightness, driving demand for advanced RF gun designs. For a bunch charge of 100 pC, a normalized emittance of less than 0.2 mm.mrad has been expected at the gun exit.
This paper presents the design of an emittance measurement device, which can accurately measure such a small emittance at the C-band RF gun exit to ensure beam quality for XFEL applications.
To achieve the desired accuracy, the primary parameters —slit width, slit thickness, and beamlet-drift length—have been systematically optimized through numerical simulations using Astra and Python based on the single-slit-scan method. Dynamic errors, including motor displacement and imaging resolution, were quantified to ensure measurement reliability.
The evaluations indicate that the measurement error of 95% emittance is less than 5%, employing a slit width of 5 μm, a slit thickness of 1 mm, and a beamlet-drift length of 0.11 m under dynamic conditions.
This optimized emittance measurement device supports precise beam quality characterization for XFELs, offering potential for further advancements in electron beam diagnostics.
, Available online ,
doi: 10.11884/HPLPB202537.250019
Abstract:
Background Purpose Methods Results Conclusions
Fiber laser coherent beam combining technology enables high-power laser output through precise phase control of multiple laser channels. However, factors such as phase control accuracy, optical intensity stability, communication link reliability, and environmental interference can degrade system performance.
This study aims to address the challenge of anomaly detection in phase control for large-scale fiber laser coherent combining by proposing a novel deep learning-based detection method.
First, ten-channel fiber laser coherent combining data were collected, system control processes and beam combining principles were analyzed, and potential anomalies were categorized to generate a simulated dataset. Subsequently, an EMA-Transformer network model incorporating a lightweight Efficient Multi-head Attention (EMA) mechanism was designed. Comparative experiments were conducted to evaluate the model's performance. Finally, an eight-beam fiber laser coherent combining experimental setup was established, and the algorithm was deployed using TensorRT for real-time testing.
The proposed algorithm demonstrated significant improvements, achieving approximately 50% higher accuracy on the validation set and a 2.20% enhancement on the test set compared to ResNet50. In practical testing, the algorithm achieved an inference time of 2.153 ms, meeting real-time requirements for phase control anomaly detection.
The EMA-Transformer model effectively addresses anomaly detection in fiber laser coherent combining systems, offering superior accuracy and real-time performance. This method provides a promising solution for enhancing the stability and reliability of high-power laser systems.
, Available online ,
doi: 10.11884/HPLPB202537.250197
Abstract:
Background Purpose Methods Results Conclusions
The ion source system for DC high-voltage accelerators operates at megavolt-level high-potential platforms, where wired communication media such as optical fibers face the risk of dielectric breakdown in compact applications due to voltage withstand constraints.
To address this, a prototype of ion source control and acquisition system based on wireless optical communication (WOC) is designed.
For the analog control and acquisition requirements of high-voltage power supplies, RF power sources, and mass flow controllers in the 2.5 MV DC high-voltage accelerator’s inductively coupled plasma (ICP) ion source system, differential-input analog-to-digital conversion (ADC) is adopted to sample raw control and acquisition signals. After digital processing, signals are transmitted via WOC. The optical signals are converted via photoelectric conversion, then reconstructed into original analog signals through digital-to-analog conversion (DAC) and amplification circuits. In this design, a ZYNQ-based digital processing platform coordinates the acquisition, transmission, and reconstruction processes, which enables ADC/DAC data interaction and stable Ethernet optical communication, ensuring the overall integrity of the wireless optical control system.
An offline test platform verified that the designed WOC system can stably control the relevant equipment in the DC high-voltage accelerator ion source system. The transmission accuracy remained within the 1.5% deviation requirement, and the link operated reliably over long durations.
Experimental results indicate that the WOC system meets the technical requirements of the BNCT project and is feasible for application in the 2.5 MV DC high-voltage accelerator ion source system.
, Available online ,
doi: 10.11884/HPLPB202537.250157
Abstract:
Background Purpose Methods Results Conclusions
The assessment of gamma radiation dose released by strong explosions is an important direction in the research of nuclear emergency protection systems. Traditional research has mostly focused on dose assessment of prompt gamma radiation (duration<1 μs）, while delayed gamma radiation (on the second timescale) is often overlooked due to time delay.
This article focuses on the study of the delayed gamma dose released by fission products after a strong explosion within 0.2-0.5 seconds, as well as the secondary gamma dose generated by neutron leakage, with the aim of systematically evaluating their radiation hazards in the near to medium range.
Based on monte carlo (MC) method, a three-dimensional full-scale model coupling strong explosive source term atmospheric transport surface activation was constructed, and a dynamic dose assessment framework based on MC multi-step calculation was proposed. By modifying the importance card method, the variance of the simulation results at medium to close distances was effectively reduced, and a detailed comparison was made between the changing trends of delayed gamma and prompt gamma doses over time and distance.
The simulation results show that within a time window of 0.2-0.5 seconds: at a distance of 500 meters from the explosion source, the total dose of delayed gamma radiation reaches 0.829 Gy, which is 1.88 times the instantaneous gamma radiation dose (0.441 Gy); At a distance of 1000 meters from the explosion source, the delayed gamma dose generated by fission products alone is 0.0318 Gy, which is 7.6 times the instantaneous gamma dose (0.0042 Gy), indicating that the hazard of delayed gamma is significantly higher than that of instantaneous gamma at longer distances. The secondary gamma dose generated by neutron leakage decays from 0.634 Gy at 500 meters to 0.0485 Gy at 1000 meters.
The dynamic dose assessment framework proposed in this article effectively reveals the significant contribution of delayed gamma radiation in the early radiation field after a strong explosion, especially at a distance where its hazard far exceeds that of instantaneous gamma radiation. This study provides key data support for optimizing nuclear emergency protection strategies.
, Available online ,
doi: 10.11884/HPLPB202537.250124
Abstract:
Background Purpose Methods Results Conclusions
The China Spallation Neutron Source (CSNS) is a high-current proton accelerator, relies on its Beam Loss Monitor (BLM) system for critical roles in equipment machine protection and residual activation dose control; in CSNS Phase I, the BLM system adopted NI’s PXIe-6358 acquisition card combined with self-developed front-end analog electronics, while the Rapid Cycling Synchrotron (RCS) of CSNS-II requires an upgraded and fully localized BLM system to meet enhanced operational demands.
This study aims to develop a novel ZYNQ-based BLM electronics system to replace the existing NI data acquisition system in CSNS-II RCS, realizing comprehensive functions including beam loss signal acquisition, gain control, Machine Protection Signal (MPS) output, and EPICS PV publishing.
The system comprises custom-developed components: a 19-inch 3U chassis with a dedicated backplane bus, 3 kV low-ripple high-voltage power modules, front-end analog boards, and digital acquisition boards based on the ZYNQ7020 System-on-Chip (SOC) integrated with AD7060 and LTC2668 , along with developed Linux drivers AXI-DMA-based ADC driver and AXI-GPIO-based gain control driver and EPICS IOC software; it was subjected to laboratory functional tests using 25 Hz, 50 μs–1 ms pulse signals to simulate ion chamber outputs and on-beam tests at the RCS local station.
Laboratory tests validated key functions such as external trigger waveform acquisition, gain control, MPS threshold output, and background subtraction, while on-beam tests at the RCS local station clearly captured beam loss signals and extraction interference signals, with the system achieving 100% localization and meeting all engineering specifications.
In conclusion, the ZYNQ-based BLM system has completed the development of core components and demonstrated full functionality, enabling it to effectively replace the existing NI acquisition system and making it well-suited for beam loss measurement in CSNS-II.
, Available online ,
doi: 10.11884/HPLPB202537.250066
Abstract:
Surface defects on optical components in high-power solid-state laser systems seriously impair the system’s operational stability and laser output performance. However, precise detection of such defects under few-shot conditions remains a critical challenge, as limited training data often restricts the generalization ability of detection models and creates an urgent need for high-performance defect detection methods adapted to this scenario. To address this issue, this study aims to design and propose an enhanced detection method dubbed ICFNetV2, which is developed based on the existing ICFNet. Its core goal is to improve the accuracy and generalization of optical component surface defect detection under few-shot scenarios. ICFNetV2 integrates data augmentation techniques with deep residual networks: its framework adopts a synergistic design of residual connection mechanisms and decoupled channel convolution operations to construct a 34-layer cascaded network—this structure mitigates gradient decay during deep network training and enhances cross-layer feature transmission efficiency. The network also incorporates spatial dropout layers and implements a data preprocessing pipeline encompassing random rotation, mirror flipping, and Gaussian noise injection, which expands the training dataset to 9 times its original size. Additionally, ablation studies were conducted to verify the efficacy of each individual network module. Experimental results demonstrate that the optimized ICFNetV2 achieves a classification accuracy of 97.4% for three typical defect types, representing a 0.7 percentage point improvement over the baseline ICFNet model. In conclusion, ICFNetV2 effectively enhances defect detection performance under few-shot conditions through architectural optimization and data augmentation. The validation from ablation studies and the observed accuracy gains confirm the effectiveness of its key modules, providing a reliable solution for surface defect detection of optical components in high-power solid-state laser systems and offering reference value for similar few-shot detection tasks.
Surface defects on optical components in high-power solid-state laser systems seriously impair the system’s operational stability and laser output performance. However, precise detection of such defects under few-shot conditions remains a critical challenge, as limited training data often restricts the generalization ability of detection models and creates an urgent need for high-performance defect detection methods adapted to this scenario. To address this issue, this study aims to design and propose an enhanced detection method dubbed ICFNetV2, which is developed based on the existing ICFNet. Its core goal is to improve the accuracy and generalization of optical component surface defect detection under few-shot scenarios. ICFNetV2 integrates data augmentation techniques with deep residual networks: its framework adopts a synergistic design of residual connection mechanisms and decoupled channel convolution operations to construct a 34-layer cascaded network—this structure mitigates gradient decay during deep network training and enhances cross-layer feature transmission efficiency. The network also incorporates spatial dropout layers and implements a data preprocessing pipeline encompassing random rotation, mirror flipping, and Gaussian noise injection, which expands the training dataset to 9 times its original size. Additionally, ablation studies were conducted to verify the efficacy of each individual network module. Experimental results demonstrate that the optimized ICFNetV2 achieves a classification accuracy of 97.4% for three typical defect types, representing a 0.7 percentage point improvement over the baseline ICFNet model. In conclusion, ICFNetV2 effectively enhances defect detection performance under few-shot conditions through architectural optimization and data augmentation. The validation from ablation studies and the observed accuracy gains confirm the effectiveness of its key modules, providing a reliable solution for surface defect detection of optical components in high-power solid-state laser systems and offering reference value for similar few-shot detection tasks.
, Available online ,
doi: 10.11884/HPLPB202537.250183
Abstract:
Gyrotron traveling wave tube (gyro-TWT) hold significant applications in millimeter-wave radar, communications, electronic warfare, and deep-space exploration. For electron beams operating in the large-orbit regime, interaction occurs exclusively with modes satisfying\begin{document}$ s=m $\end{document} ![]()
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Gyrotron traveling wave tube (gyro-TWT) hold significant applications in millimeter-wave radar, communications, electronic warfare, and deep-space exploration. For electron beams operating in the large-orbit regime, interaction occurs exclusively with modes satisfying
, Available online ,
doi: 10.11884/HPLPB202537.250114
Abstract:
Background Purpose Methods Results Conclusions
Neutral beam injection (NBI) systems are critical to fusion research and require precise control and monitoring of negative ion source. Existing solutions often have limitations in terms of development efficiency and adaptability.
This study aims to design and implement a cost-effective, highly scalable NBI control and monitoring system for negative ion source. The system is specifically designed to address the inherent issues of traditional NI-PXIe hardware and LabVIEW-FPGA architectures, such as lengthy development cycles, high hardware costs, and limited scalability.
A modular control solution is proposed, utilizing a domestically produced PXIe platform, a Linux real-time system, and the Qt5.9 framework. By replacing imported components with locally sourced hardware and leveraging optimizations in the Linux real-time kernel, precise control is achieved. A multi-threaded control program is developed using C++ object-oriented programming to enhance system flexibility and overcome scalability limitations.
Experimental verification confirmed that the system achieved microsecond-level synchronisation accuracy. Compared with traditional methods, this solution has significant advantages in scalability and control accuracy, meeting all experimental requirements for time-sensitive operations in negative ion source NBI.
The QT-based system successfully addresses the limitations of traditional NBI control architectures in terms of cost and scalability. By adopting localised hardware, Linux real-time system, and modular C++ design, the system provides reliable performance for complex ion source experiments. This approach establishes a flexible framework that can adapt to further enhancements in future NBI systems.
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).
Display Method:
, Available online ,
doi: 10.11884/HPLPB202537.250071
Abstract:
Background Purpose Methods Results Conclusions
The Vlasov equation is a cornerstone in plasma physics, governing the evolution of distribution functions in high-temperature, collisionless plasmas. Conventional numerical methods, including Eulerian and Lagrangian approaches, often encounter severe computational challenges due to the rapid increase in cost with fine grid resolutions and the curse of dimensionality. These limitations restrict their effectiveness in large-scale kinetic plasma simulations needed in fusion research and space plasma studies.
This work aims to develop an efficient and scalable computational framework for solving the Vlasov equation that mitigates the drawbacks of traditional methods. The study particularly addresses the need for maintaining accuracy and physical consistency while significantly reducing computational costs in high-dimensional simulations. An approach based on the physics-informed Fourier neural operator (PFNO) is introduced.
The method integrates the high-dimensional function mapping ability of the fourier neural operator with the physical constraints of the Vlasov equation. A physics-informed loss function is constructed to enforce mass, momentum, and energy conservation laws. The framework was evaluated through benchmark tests against finite element and spectral solvers, and its parallel performance was assessed on large-scale computing platforms.
The PFNO approach demonstrates accuracy comparable to conventional solvers while achieving computational efficiency improvements of one to two orders of magnitude. The method shows strong generalization under sparse-data conditions, exhibits grid independence, and scales effectively in parallel computing environments, enabling efficient treatment of high-dimensional plasma dynamics. The study presents a novel paradigm for solving high-dimensional Vlasov equations by combining deep learning operators with physical principles.
The PFNO framework enhances efficiency without sacrificing physical accuracy, making it a promising tool for applications in inertial confinement fusion, astrophysical plasma modeling, and space plasma simulations. Future research directions include extension to multi-species and relativistic plasma systems.
, Available online ,
doi: 10.11884/HPLPB202537.250161
Abstract:
Background Purpose Methods Results Conclusions
The fast orbit feedback (FOFB) system of the high energy photon source (HEPS) has been developed for the beam orbit control in its storage ring. It mainly consists of beam position monitors (BPMs), the algorithms of fast orbit controller (FOC) and fast correction units. To support HEPS commissioning, we have developed a high-performance signal generator to complete the simulation of beam signals.
The developed signal source includes four output ports with independently adjustable signal amplitudes and synchronous triggers. Its goal is to simulate the timing signals, and enable the simulation output of BPM signals under real beam conditions in the laboratory without beam, with the advantages of simple structure, low cost and high repeatability.
The core of the signal source is an FPGA board. Firstly, a 250 MHz clock signal with a 25% duty cycle was generated by the PLL and directly routed through the MRCC pin. After completing the impedance matching, the RF signal was processed via differential circuit to obtain the required simulated beam signals. Then, the required signals were amplified using the RF amplifier. After the 1∶4 power division, beam signals with four adjustable amplitudes output channels were finally acquired. The trigger signal was supplied directly from the FPGA I/O pins configured for LVCMOS33 operation at 3.3 V, to meet the required LVTTL of BPM electronics.
Based on the beam current characteristics of the HEPS storage ring, we tested the beam signal simulation performance of HEPS storage ring with a frequency of 220 kHz and different patterns during the experiment. In addition, the simulation performance of the single trigger signal and BEPCII collision zone with a frequency of 1.21 MHz has also been tested. The test results showed that the developed signal source could simulate the beam signal well and meet the design requirements. Then, we tested the pattern dependence of HEPS BPM electronics with this signal source. The results showed that there was no pattern dependence effect in the HEPS BPM electronics used in this experiment.
This signal generator could be used to assist in the logical design and correctness of DBPM, to debug the data transmission and control logic between the DBPM and FOFB, and to test the latency of the FOFB system. Based on this system, the debugging difficulty of BPM and FOFB systems could be reduced and accelerate the deployment of the FOFB system.
Modeling and calculation of radiation effects of high-energy rays on PCB inside a shielded enclosure
, Available online ,
doi: 10.11884/HPLPB202537.250098
Abstract:
Background Purpose Methods Results Conclusions
X/γ-ray irradiation of an electronic system shielding box will penetrate the box body, generate photoelectrons or Compton electrons on the surface layers or inside the system, and excite electromagnetic pulses. These particles or electromagnetic fields will interfere with or even damage the sensitive electronic components of the electronic system inside the box, affecting the regular operation of the electronic system.
To rapidly assess the particle and electromagnetic environment inside electronic systems under radiation exposure and enable timely protective measures that mitigate radiation-induced damage and ensure reliable operation.
We present a theoretical analysis of irradiation responses arising from two coupling mechanisms: electromagnetic pulses excited by primary particles within the cavity of a shielded enclosure and their field-to-circuit coupling to a printed circuit board (PCB), and direct multi-layer penetration coupling of ionizing radiation. Equivalent-circuit models were constructed to represent these coupling paths, and transient current responses were calculated analytically.
The transient current responses of the shielded enclosure under high-energy radiation, computed using the equivalent-circuit approach, reproduce the trends observed in published experimental measurements and exhibit approximate numerical agreement.
The results validate the proposed theoretical modeling approach, showing that analytical equivalent-circuit analysis can provide rapid, simulation-free estimates of radiation effects on electronic systems. The method can be extended to scenarios that more closely match practical applications.
, Available online ,
doi: 10.11884/HPLPB202537.250149
Abstract:
Background Purpose Methods Results Conclusions
The high peak power and wide spectral characteristics of high-power radar may cause unintended interference to communication systems operating in adjacent frequency bands.
This study aims to clarify the effects of key LFM waveform parameters on interference mechanisms and to describe their governing patterns.
A closed-loop injection platform based on software-defined radio (SDR) was developed to inject synthesized LFM waveforms into a QPSK receiver. Error vector magnitude (EVM) serves as the performance metric, while pulse width, pulse period, and chirp bandwidth are varied systematically under fixed duty-cycle constraints.
Results indicate that increasing the duty cycle significantly raises the EVM value, although its growth moderates beyond a 30% duty cycle. Under constant duty cycles, pulse-period variations show negligible influence on EVM. As chirp bandwidth increases from 1 MHz to 3 MHz, the EVM decreases from −10.5 dB to −19.8 dB, a reduction of 9.3 dB, but remains nearly constant with further bandwidth expansion to 10 MHz.
These findings offer critical insights into radar-communication spectrum coexistence and anti-interference system design, while confirming the effectiveness of SDR-based platforms for investigating high-power microwave (HPM) interference effects.
, Available online ,
doi: 10.11884/HPLPB202537.250160
Abstract:
Background Purpose Methods Results Conclusions
Traveling-wave tubes (TWTs) are widely applied in radar, imaging, and military systems owing to their excellent amplification characteristics. Miniaturization and integration are critical to the future of TWTs, with multi-channel slow-wave structures (SWSs) forming the foundation for their realization in high-power vacuum electronic devices.
To provide design insights for multi-channel TWTs and simultaneously enhance their output power, a W-band folded-waveguide TWT with dual electron beams and H-plane power combining was proposed.
Three-dimensional electromagnetic simulations in CST were conducted to verify the high-frequency characteristics, electric field distribution, and amplification performance of the proposed SWS, thereby confirming the validity of the design.
Results indicate that the designed TWT achieves a transmission bandwidth of 10 GHz. With an electron beam voltage of 17.9 kV and a current of 0.35 A, the output power reaches 450 W at 94 GHz, corresponding to an efficiency of 7.18% and a gain of 23.5 dB. Moreover, under fixed beam voltage and current, the TWT delivers over 200 W output power across 91–99 GHz, with a 3 dB bandwidth of 91–98.5 GHz. The particle voltage distribution after modulation further validates the mode analysis.
These results demonstrate the feasibility of compact dual-beam power-combining structures and provide useful guidance for the design of future multi-channel TWTs.
, Available online ,
doi: 10.11884/HPLPB202537.250122
Abstract:
Background Purpose Methods Results Conclusions
Pulse drive sources are critical components of high-power microwave systems. Existing drive sources based on Tesla+PFL or LTD technology offer good waveform quality but are limited by their large size and weight. PFN-Marx technology sequentially stacks voltages during pulse discharge, which requires relatively low insulation and makes it an ideal technical approach for drive source miniaturization. However, current PFN-Marx-based drive sources struggle to balance compact structural design with output waveform quality.
This study aims to design a compact high-power pulse drive source based on PFN-Marx technology to meet the requirements of a specific high-power microwave system.
To achieve this goal, a 7-stage unipolar pulse charging PFN-Marx generator is employed, with a high-power constant-current charging power supply powered by lithium batteries used to charge the primary capacitor of the Tesla transformer. The PFN modules are designed with identical charging loop inductors to ensure synchronized pulse charging waveforms, and their modular structure allows for flexible scalability. Additionally, the air-core Tesla transformer (with a coupling coefficient greater than 0.8) is integrated with the PFN-Marx within a high-voltage chamber filled with SF6 gas to ensure insulation.
The results show that the drive source outputs a single pulse energy of 45.6 J, and can output a quasi-square wave pulse at a 75 Ω load, with an amplitude of −189.2 kV, a pulse width of 93.2 ns, a rise time of 8.4 ns, and a peak power of 477 MW. The lithium-ion battery charging and control power supply has dimensions of 482 mm×443 mm×177 mm and weighs 12.6 kg; the integrated Tesla transformer and PFN-Marx generator have dimensions of ϕ370 mm×848 mm and weigh 28.7 kg. At a repetition rate of 5 Hz, the average output voltage is −183.4 kV, with a voltage dispersion of 4.1%.
Therefore, this compact PFN-Marx-based pulse drive source achieves both miniaturization and high-quality waveform output, laying the foundation for the development of higher-power and higher-performance compact pulse drive sources.
, Available online ,
doi: 10.11884/HPLPB202537.250138
Abstract:
Background Purpose Methods Results Conclusions
High-power microwave (HPM) pulses, which can interfere with or damage electronic components and circuits, have attracted considerable research interest in recent years. Aperture coupling represents a primary mechanism for such pulses to penetrate shielded metallic enclosures, significantly affecting the electromagnetic compatibility and resilience of electronic systems. Although substantial studies have focused on shielding effectiveness and resonant behaviors, the spatial distribution of coupling parameters—particularly the extent of strongly coupled regions within the cavity—remains inadequately investigated. This paper proposes a quantitative metric termed “the coverage rate of strong-coupled region” to better evaluate HPM backdoor coupling effects.
The objective is to systematically examine the influence of key HPM waveform parameters on this coverage rate within a representative metallic cavity.
A three-dimensional simulation model of a rectangular metallic cavity with an aperture was developed using the finite-difference time-domain (FDTD) method. The internal field distribution was monitored via an array of electric field probes. Numerical simulations were performed to assess the effects of various HPM parameters, including frequency, pulse width, the pulse rise time, and polarization angle, on the coverage of strongly coupled regions.
The coverage rate was markedly higher at the cavity’s inherent resonant frequencies than at non-resonant frequencies. Increasing the pulse width led to a saturation of coverage beyond a specific threshold. Variations in polarization angle from horizontal to vertical considerably enhanced the coverage, with vertical polarization yielding the maximum value. Superimposing multiple resonant frequencies effectively compensated for weakly coupled areas, further increasing the overall coverage. In contrast, the pulse rise time had a negligible effect on the coverage rate. The proposed the coverage rate of strong-coupled region effectively addresses the practical dilemma wherein strong local coupling does not necessarily lead to significant system-level effects.
This metric provides a quantitative basis for optimizing the alignment between sensitive components and highly coupled zones. Frequency and polarization are identified as decisive parameters for enhancing coupling effectiveness, while pulse width and multi-frequency excitation can be utilized to achieve more uniform and robust coupling coverage. These findings offer valuable guidance for the design and assessment of HPM protection measures and electromagnetic compatibility analysis.
Column
- Cover and Contents
- Special Issue on Interaction of Ray with Matter
- Theory of Interaction of Ray with Matter and Its Numerical Methods
- Detection Technology and Instruments of Rays
- Nuclear Reactions, Radiation Protection, and Radiation Hardening Technology
- Application of Rays in Materials Science
- Ray Physics in Nuclear Reactors and Accelerators
- Applications of Ray in Medicine and Biological Sciences
- Physics and Technology of Electromagnetic Pulse
- Frontier Technologies in Interaction of Ray with Matter
Display Method:
2025, 37: 106002.
doi: 10.11884/HPLPB202537.250211
Abstract:
Background Purpose Methods Results Conclusions
Radiation imaging technology, as an important diagnostic, has been widely used in scientific devices such as inertial confinement fusion and flash photography. It has been found that unexpected low-frequency components usually exist in the point spread function (PSF) of radiation imaging systems, leading to the so-called low-frequency blur or long-range blur. Because of long-range blur, the image grayscale varies nonlinearly with the ray flux, which in turn interferes with the analysis of the object density or the source intensity. Experimental measurement of the low-frequency components is challenging because of their extremely low intensity. The specific sources of low-frequency components are not very clear currently.
This study aims to address these challenges by proposing a new experimental method for measuring the low-frequency components. The goal is to ensure the reliability of the measurement data on low-frequency components and to identify the main sources of low-frequency components.
A series of experiments were conducted on different components of the imaging system. A collimator called ring-aperture was used to modulate the x-ray or optical photons into a circular pattern, which led to a significant increase in the signal strength from low-frequency components by orders of magnitude.
A direct measurement result of the low-frequency components was obtained for the first time, and the measurement lower limit was extended to 10−6 relative to the peak of PSF. Experiments showed that the surface state of scintillators can have a significant impact on low-frequency components. By blackening the non-light-emitting surface, the low-frequency components caused by scintillator can be reduced by 22% to 62%.
The ring-aperture method provides a reliable experimental approach for measuring low-frequency components of the PSF. The research results indicate that optical photon transport is an important factor leading to long-range blur. By surface treatment of scintillators, such as blackening and polishing, long-range blur can be effectively suppressed.
2025, 37: 106003.
doi: 10.11884/HPLPB202537.250201
Abstract:
Background Purpose Methods Results Conclusions
In near-field pulsed neutron measurements (at distances of less than 1 m), large-sized plastic scintillators (ϕ100 mm × 100 mm) exhibit neutron sensitivity deviation due to geometric discrepancies between calibration and measurement, and the inverse-square law has limited applicability under close-proximity conditions, hindering accurate metrology.
To address this deviation, reduce systematic errors from traditional single-point calibration, and extend the neutron sensitivity calibration range, this study proposes a dual-extrapolation dynamic calibration method combining experimental extrapolation with Monte Carlo (MC) simulation.
An MC model was established to quantify the distance’s effect on sensitivity, and a scattering background extrapolation method was developed via near-field experiments for close-proximity sensitivity measurement.
MC results show that the source-to-detector distance of less than 80 cm significantly impacts sensitivity, with an 8.44% correction factor at 20 cm; experiments validated the simulation accuracy.
This method effectively mitigates sensitivity deviation, clarifies the inverse-square law’s limitations under close proximity, extends the calibration scope, and provides a new technical approach for precise neutron metrology in harsh environments such as pulsed reactor transient diagnostics and fusion devices.
2025, 37: 106004.
doi: 10.11884/HPLPB202537.250158
Abstract:
Background Purpose Methods Results Conclusions
More than 70% of the energy from a high-altitude nuclear explosion is transmitted via X-ray radiation, which serves as the primary source of atmospheric ionization. When the detonation altitude of a high-altitude nuclear explosion exceeds 80 km, the absorption of X rays by air weakens. Consequently, X rays can propagate over a wide range and gradually dissipate their energy through the ionization of the atmosphere. The atmospheric ionization effect of X rays causes drastic fluctuations in the electron density within the Earth’s ionosphere. This, in turn, leads to significant changes in the signals of electromagnetic waves as they pass through the ionosphere, thereby exerting adverse impacts on systems such as satellites, radars, and communications. However, there are currently still problems such as slow calculation speed and incomplete model considerations in the calculation of the atmospheric ionization effect caused by high-altitude X rays.
The purpose of this paper is to propose a new engineering method for calculating the X-ray atmospheric ionization process in the high-altitude rarefied atmosphere.
The model accounts for the transport of high-energy electrons (generated by the interaction between X rays and the atmosphere) in the geomagnetic field as well as the atmospheric ionization issue, and it performs an averaging process on the microscopic interaction processes.
Compared with traditional ray energy deposition models, it improves the calculation accuracy.
This model was used to analyze the influence laws of explosion altitude, latitude, and yield on the ionization density distribution. The results show that: Due to the influence of high-energy electron transport, the symmetry of the ionization density distribution is lost; The ionization density distribution is significantly enhanced in the direction passing through the explosion center and perpendicular to the magnetic field lines; The higher the explosion altitude, the greater the ionization density at high-altitude positions, while the influence caused by high-energy electron transport becomes smaller in high-altitude regions, and the ionization density at low-altitude positions decreases; The yield has a significant impact on the numerical value of the ionization density, but has a relatively small impact on the relative distribution of the ionization density.
2025, 37: 106005.
doi: 10.11884/HPLPB202537.250208
Abstract:
Background Purpose Methods Results Conclusions
Space charge effects pose a significant challenge in high-current ion beam transport, particularly in low-energy beam transport (LEBT) systems where beam intensity is high and energy is relatively low. Active injection of gas has been proposed as an effective method to mitigate these effects. However, for negative hydrogen ion beams, the physical mechanisms involved are highly complex due to competing processes such as ionization, electron stripping, etc.
This study aims to investigate the interaction mechanisms between negative hydrogen ion beams and gas within an LEBT system, and to evaluate the influence of gas species and pressure on beam parameters including emittance and beam current.
Numerical simulations based on the particle-in-cell (PIC) method were conducted using the Warp code, incorporating physical processes including ionization, electron stripping, and elastic scattering. A three-dimensional simulation model was established to analyze space charge compensation effects under nitrogen and argon gas environments. Experimental measurements of beam current and emittance were simultaneously carried out at the XiPAF accelerator facility to validate simulation results.
Both simulations and experiments revealed that the effects of gas scattering and electron stripping cannot be neglected in space charge compensation of negative hydrogen ion beams.
This research highlights the complexity of space charge compensation in negative hydrogen ion beams and emphasizes the need to consider multiple physical interactions in the design and operation of high-current LEBT systems. The findings provide practical insights for optimizing gas compensation parameters in similar accelerator facilities.
2025, 37: 106006.
doi: 10.11884/HPLPB202537.250218
Abstract:
Background Purpose Methods Results Conclusions
A radiation field with a significant mixture of neutrons and gamma rays exhibits the following characteristics: a wide range of neutron energy, serious mixing of neutron and gamma ray, etc. Therefore, to measure the total neutron emission from such a source with relatively high precision, the detector must possess high neutron sensitivity, a flat energy response, and a strong n/γ discrimination capability.
To this end, a neutron detector based on a combined 4He gas scintillator is proposed, which has the advantages of a flat neutron energy response and high n/γ resolution. The neutron sensitivity of the detector is studied in this paper.
Using the Monte Carlo method, simulations were conducted to calculate the energy deposition of recoil protons and recoil helium nuclei generated by interactions of neutrons with polyethylene targets and 4He nuclei in the gas, as well as the neutron sensitivity of the detector.
The computational results indicate that the energy deposition curve for 1–15 MeV neutrons in the 4He gas is remarkably flat, with the detector’s neutron sensitivity to 1–15 MeV neutrons reaching approximately 4.0×10−15 C·cm2. Experimental calibration of the detector’s neutron sensitivity was performed using the K600 high-voltage multiplier at the China Institute of Atomic Energy.
The theoretical results of neutron sensitivity are in good agreement with the experimental results. The theoretical calculation model of the detector proposed in this paper correctly calculates the neutron sensitivity, and the detector's performance meets the expected targets.
2025, 37: 106007.
doi: 10.11884/HPLPB202537.250230
Abstract:
Background Purpose Methods Results Conclusions
With the continuous development of national strategic needs, multiple large-scale radiation simulation facilities have been constructed, imposing increasingly stringent requirements on the temporal and spatial resolution of radiation detection. Researchers have been actively developing novel techniques to achieve higher resolution. Against this background, the technique utilizing the transient refractive index response of semiconductor crystals for radiation detection has gained significant attention.
This study presents a novel approach based on refractive index changes in indium phosphide (InP) crystals to enhance the temporal and spatial resolution of radiation detection. A proof-of-principle experiment was conducted to validate the effectiveness of the proposed technique for pulsed radiation detection.
A radiation imaging system was constructed based on a Michelson interferometer configuration. This system used a 350 μm thick iron-doped InP crystal as the radiation sensor.
Using this setup, images of refractive index changes within the crystal induced by laser pulse excitation with a wavelength of 532 nm were successfully captured. Pump-probe measurements revealed that the iron-doped InP crystal exhibited a time response of 1.5 ns under pump laser irradiation. Spatial resolution was characterized by placing a resolution target in the pump beam path; image reconstruction achieved a system spatial resolution of 1 lp/mm.
These experimental results demonstrate the feasibility of the ultrafast image detection technology based on InP refractive index changes. This system has the potential to significantly advance pulsed radiation beam detection technology, offering high temporal and spatial resolution capabilities.
2025, 37: 106008.
doi: 10.11884/HPLPB202537.250227
Abstract:
Background Purpose Methods Results Conclusions
Efficient neutron detectors are widely used in national security, neutron scattering, and nuclear energy development. The 3He proportional tube, a commonly used neutron detector, faces a global shortage of 3He resources. Meanwhile, existing alternative detectors like BF3 proportional tubes have low efficiency and toxicity, and most large-area boron-lined gas detectors adopt a flow-gas design requiring gas cylinders, causing inconvenience in use and maintenance.
To address the above issues, this study aims to develop a sealed large-area neutron detector based on a boron-lined multi-wire proportional chamber (MWPC) for nuclear environment safety monitoring and fusion pulsed neutron measurement.
The Geant4 software with the FTFP_BERT_HP physics library was used to simulate the effect of boron coating thickness on detection efficiency, energy deposition of secondary particles in the working gas, and γ-ray sensitivity. A double-layer sealed detector with a 1.6 μm boron coating and a 10 cm×10 cm effective area was fabricated. Performance tests (pulse height spectrum and neutron detection efficiency) were conducted at the 20th beamline (BL20) of the China Spallation Neutron Source (CSNS), using a self-developed readout electronics system and a standard 3He tube as a reference.
Simulation showed that thermal neutron detection efficiency was 1%−7% when boron coating thickness was 0.1−2.5 μm, and γ-ray sensitivity was less than 5×10−6 at a 100 keV energy threshold. Experimental results indicated that the detector’s pulse height spectrum matched the simulated energy deposition. After background subtraction, its detection efficiencies for 0.18 nm, 0.29 nm, and 0.48 nm neutrons were 4.2%, 6.0%, and 9.4%, respectively, consistent with the 10B neutron absorption cross-section law.
The developed sealed large-area boron-lined MWPC neutron detector avoids complex gas circulation systems. Future optimization of boron coating thickness and conversion layer number can further improve efficiency, providing a new solution for nuclear safety monitoring and fusion pulsed neutron measurement.
2025, 37: 106009.
doi: 10.11884/HPLPB202537.250196
Abstract:
Background Purpose Methods Results Conclusions
Gallium nitride (GaN) exhibits exceptional optoelectronic properties, making it highly suitable for applications in high-power devices, light-emitting diodes (LEDs), high-electron-mobility transistors (HEMTs), and radiation detectors. Particularly in radiation detection, GaN can function as both a semiconductor and a scintillator. As a scintillator material, it demonstrates high luminescence efficiency. However, the yellow luminescence band induced by defects in the material often leads to slow time response, limiting its broader application. On the other hand, GaN-based LEDs with multi-quantum well (MQW) structures can achieve excellent electroluminescence performance. Nevertheless, MQW-enhanced scintillators generally suffer from drawbacks such as a thin sensitive layer and low energy deposition efficiency.
To leverage the advantageous properties of GaN comprehensively and achieve higher overall performance in detection, this study proposes a radiation-to-optical conversion detection mode that combines GaN semiconductor devices for simultaneous radiation energy deposition and carrier recombination luminescence. By constructing a PN junction structure incorporating MQWs on a high-resistivity, high-mobility GaN substrate, a radiation detection device capable of both radiation-to-carrier conversion and carrier recombination luminescence is realized.
A 400 μm-thick unintentionally doped high-resistivity GaN single crystal was used as the radiation energy deposition layer. A PN junction structure with MQWs was epitaxially grown on the high-resistivity GaN substrate via metal-organic chemical vapor deposition (MOCVD). The epitaxial layer was segmented into independent regions using inductively coupled plasma (ICP) etching. Transparent indium tin oxide (ITO) electrodes were subsequently fabricated via magnetron sputtering, followed by the deposition of metal electrodes on both the top and bottom surfaces of the device.
The device exhibited low dark current and sensitive X-ray response characteristics. A multi-quantum well recombination structure with a luminescence peak at 410 nm was incorporated into the device. Luminescence spectrum tests and imaging analysis confirmed the device’s response to varying radiation doses and changes in luminescence efficiency under different applied voltages.
The designed device enables directional drift and recombination luminescence of carriers generated by radiation energy deposition under an applied electric field. By leveraging semiconductor device design and electric-field-regulated carrier behavior, the luminescence efficiency, response time, and emission spectrum of the device can be effectively modulated. This approach offers a novel technical pathway for radiation detection.
2025, 37: 106010.
doi: 10.11884/HPLPB202537.250202
Abstract:
Background Purpose Methods Results Conclusions
A new NPN structure detector based on SiC with internal gain characteristics was designed successfully.
This study aims to analyze the effect of area on the NPN detectors.
This research involves the design and fabrication of three dual-end SiC-based NPN structure radiation detectors with different areas. Their DC X-ray response characteristics were experimentally evaluated.
The results demonstrate that these detectors operate under the combined effects of externally biased voltage and photovoltaic voltage, exhibiting four distinct knee-points that divide the I-V characteristic curve into five stages. Under identical DC X-ray irradiation conditions, larger-area detectors absorb more X-ray energy, leading to stronger output signals. Smaller-area detectors show higher knee-points on the I-V characteristic curve, indicating a greater ability to withstand voltage. Additionally, the response time of the detectors is closely related to their size, with larger areas resulting in longer switch-off times. The 90%-10% fall time of the 1 cm×1 cm detector is approximately 12.2 ms longer than that of the 0.25 cm×0.25 cm detector.
These findings emphasize the importance of considering area in the design of radiation detectors and highlight the need to optimize this parameter to enhance the detector performance.
2025, 37: 106011.
doi: 10.11884/HPLPB202537.250269
Abstract:
Background Purpose Methods Results Conclusions
The space radiation environment poses a critical threat to spacecraft electronics, with single-event upset (SEU) being one of the most representative transient radiation effects. Understanding the spatial distribution and driving mechanisms of SEUs is essential for improving radiation-hardened design and mission reliability.
This study aims to systematically investigate the relationship between on-orbit SEUs and space environment parameters, and to quantify the contribution of high-energy protons to SEU occurrence.
On-orbit SEU monitoring data from static random-access memory (SRAM) devices were analyzed in conjunction with particle flux measurements, geomagnetic parameters, and proton energy spectra. The spatial distribution of SEUs was mapped in L-shell coordinates, and statistical correlation analysis was performed between the flux of protons at or above 10 MeV and on-orbit soft error rate (SER). Theoretical SER was calculated using ground-based proton irradiation cross sections and compared with observed values.
A total of 97.5% of SEU events were concentrated within the South Atlantic Anomaly (SAA), with a peak at L ≈ 1.24−1.25, coinciding with enhanced the flux of protons at or above 10 MeV regions. A significant power-law correlation (R ≈ 0.73) was found between the flux of protons at or above 10 MeV and SER, confirming high-energy protons as the dominant driver of SEUs. The calculated SER agreed with observations within one order of magnitude but was systematically lower, indicating the need for extending the spectral range to improve prediction accuracy. No SEUs were detected during three minor solar proton events, while geomagnetic storms caused significant SER decreases due to proton flux depletion in the SAA.
This study systematically elucidates the spatial distribution characteristics and primary driving mechanisms of on-orbit SRAM SEUs, demonstrating that high-energy proton flux is the dominant contributor to SEU occurrence. These findings advance the understanding of space radiation effects and provide essential theoretical and experimental support for radiation effect modeling, radiation-hardened design, and mission reliability assessment.
2025, 37: 106012.
doi: 10.11884/HPLPB202537.250193
Abstract:
Background Purpose Methods Results Conclusions
Accurate resonance calculation for multi-ring fuel elements remains a significant challenge in reactor physics due to the complex spatial self-shielding effects and strong mutual interference between resonant nuclides. Traditional resonance methods, such as the subgroup method, often struggle to achieve a balance between computational efficiency and accuracy when dealing with such configurations. This is particularly critical for high-fidelity analysis of advanced reactors and experimental facilities like the high-flux engineering test reactor, where precise characterization of resonance phenomena is essential for predicting core performance and safety parameters.
This study aims to address the limitations of existing resonance calculation methods for multi-ring fuel systems by developing a novel global-local coupling framework. The primary objectives are to enhance the accuracy of effective self-shielding cross-section computation for resonant nuclides, improve computational efficiency, and validate the method’s applicability for both assembly-level and full-core simulations.
A multi-ring fuel resonance calculation method based on the global-local coupling method (MRFRCM) was proposed specifically for multi-ring fuel analysis. In this approach, when handling global spatial effects, the entire multi-ring fuel is treated as an integrated black body. This process simplifies the multi-ring fuel problem into an equivalent rod-type fuel problem for calculating the global Dancoff correction factor. Subsequently, an equivalent one-dimensional local problem is established through a conservation-based search of the Dancoff correction factor. Finally, the problem is reverted to a one-dimensional multi-ring fuel configuration, where the ultra-fine group method is employed to obtain precise self-shielding cross-sections. The method was implemented and tested on multi-ring fuel assembly problems to evaluate its precision and efficiency. Furthermore, it was applied to two-dimensional and three-dimensional full-core models of a high-flux engineering test reactor to assess its performance in practical scenarios.
The proposed method demonstrated superior accuracy and computational efficiency compared to the traditional subgroup method. In assembly-level calculations, the global-local approach reduced errors in effective cross-section estimation while maintaining competitive computation times. For full-core simulations, the results showed good agreement with reference solutions. The method also exhibited robust performance in handling complex geometries and heterogeneous material configurations.
The MRFRCM provides an effective solution for high-accuracy resonance modeling in multi-ring fuel systems. It significantly outperforms the traditional subgroup method in both precision and efficiency, making it suitable for large-scale reactor physics applications. The successful application to 2D and 3D full-core analyses confirms its practicality and reliability for simulating high-fidelity reactor core behavior. Future work will focus on extending the method to broader energy ranges and more complex reactor types.
2025, 37: 106013.
doi: 10.11884/HPLPB202537.250214
Abstract:
Background Purpose Methods Results Conclusions
Phase-locked loops (PLL) circuit plays a significant role in microprocessor clock circuits and high-speed interface circuits. Conducting research on the strong radiation effect of PLL circuits could provide basic data for evaluating their overall damage response.
In consideration of transistors’ energy deposition fluctuation to be more close to practical radiation, the total ionizing dose (TID) effect of a typical 0.18 μm process phase-locked loops circuit (PLL) was equivalently studied, which could make up for the deficiencies of previous related research.
Employing Monte Carlo sampling method to modify the sensitive parameters of the transistor SPICE model, the TID effect of PLL circuit was studied, where the statistical distributions of output frequency f, phase difference δ, and control voltage Vvco_in under different TID ranging from 0 to 200 krad (SiO2) are given.
Results demonstrate that the values of f and δ would be changed in various degrees under TID effect without considering the energy deposition fluctuations, and they could eventually return to normal through the circuit’s feedback mechanism. On the contrary, when considering the energy deposition fluctuations, the PLL circuit shows an unexpected frequency response after phase locking, which may lead to data loss during the communication process and disturbances to the processor’s functionality, thus leading to a disaster’s impact on the overall behavior of the circuit.
The simulation methods and results in this paper could provide references for considering or evaluating TID effect of PLL circuits under real conditions, and further offer suggestions on the design of anti-TID effect of PLL circuits.
2025, 37: 106014.
doi: 10.11884/HPLPB202537.250246
Abstract:
Background Purpose Methods Results Conclusions
Boron neutron capture therapy (BNCT) dose simulation is the cornerstone for equipment development, drug iteration, and clinical trials.
To meet the need for BNCT dose simulation and analysis based on clinical CT, we propose and build a brand-new BNCT dose simulation system.
Within the medical-image platform MeVisLab, we complete DICOM registration, target delineation, and RTStruct/RTDose interfaces; the open-source Monte Carlo code OpenMC is used as the engine to execute neutron-transport simulation, realizing HU-to-material mapping and variable-mesh calculation.
Validation with clinical CT data simulated by the system shows that at a depth of 22 cm in the tumour target, the boron dose accounts for 80.9% of the total dose.
Developed within weeks and with low licence costs, the system provides an efficient calculation tool for BNCT dose simulation and a reference framework for BNCT dose simulation in research and education.
2025, 37: 106015.
doi: 10.11884/HPLPB202537.250212
Abstract:
Neutron diffraction technology has become a vital characterization tool in semiconductor material research due to its penetration capability, sensitivity to light elements, and dynamic detection advantages. By analyzing diffraction peak characteristics, this technique reveals lattice distortions, strain distributions, and defect evolution patterns, providing atomic-scale insights into material properties. It enables quantitative analysis of defects such as dislocation density and cation occupancy while investigating magnetic ordering and spin interaction mechanisms, supporting the development of novel electronic devices. Its in-situ testing capability allows real-time observation of defect reorganization during phase transitions and structural responses under external fields, overcoming the limitations of conventional methods, particularly in extreme-environment material studies. Current research focuses on establishing correlations between microstructural evolution and macroscopic performance, advancing in-situ dynamic testing methods for precise material behavior prediction. With upgrades to large-scale scientific facilities, neutron diffraction will play an increasingly significant role in both fundamental research and engineering applications of semiconductor materials, especially in harsh-environment material development. Future advancements will prioritize enhancing multiscale characterization capabilities and innovating in-situ experimental approaches, providing robust technical support for semiconductor materials science.
Neutron diffraction technology has become a vital characterization tool in semiconductor material research due to its penetration capability, sensitivity to light elements, and dynamic detection advantages. By analyzing diffraction peak characteristics, this technique reveals lattice distortions, strain distributions, and defect evolution patterns, providing atomic-scale insights into material properties. It enables quantitative analysis of defects such as dislocation density and cation occupancy while investigating magnetic ordering and spin interaction mechanisms, supporting the development of novel electronic devices. Its in-situ testing capability allows real-time observation of defect reorganization during phase transitions and structural responses under external fields, overcoming the limitations of conventional methods, particularly in extreme-environment material studies. Current research focuses on establishing correlations between microstructural evolution and macroscopic performance, advancing in-situ dynamic testing methods for precise material behavior prediction. With upgrades to large-scale scientific facilities, neutron diffraction will play an increasingly significant role in both fundamental research and engineering applications of semiconductor materials, especially in harsh-environment material development. Future advancements will prioritize enhancing multiscale characterization capabilities and innovating in-situ experimental approaches, providing robust technical support for semiconductor materials science.
2025, 37: 106016.
doi: 10.11884/HPLPB202537.250215
Abstract:
Background Purpose Methods Results Conclusions
System-generated electromagnetic pulse (SGEMP) effects induced by X-ray irradiation pose a significant threat to electronic systems in aerospace and nuclear environments. Accurate quantification of electron emission parameters, which are critical current sources for SGEMP simulations, remains challenging because of the complex coupled photon-electron transport processes involved.
This study aims to systematically investigate the characteristics of backward- and forward-emitted electrons from typical materials (e.g., aluminum) under X-ray irradiation and develop efficient analytical models for predicting electron yields without relying on computationally intensive Monte Carlo (MC) simulations for each new scenario.
Photon-electron coupled transport simulations were performed using a Monte Carlo module combining the condensed history and single-event methods. The energy and angular distributions of emitted electrons were analyzed for X rays (0.1–100 keV) normally incident on aluminum plates of varying thicknesses. Analytical models for backward and forward electron yields were derived based on photon mean free path, electron maximum range, and attenuation laws, with a cumulative correction factor introduced to improve forward yield accuracy.
Backward electron energy spectra exhibited a double-peak structure (Compton and photoelectron peaks), with angular distributions following a cosine law. A saturation thickness of about 3 photon mean free paths was identified for backward yield, beyond which yields remained constant. For forward emission, yields peaked at the electron maximum range thickness and decreased with further increasing plate thickness. The proposed analytical formulas for both backward and forward yields achieved relative errors within 10% compared to direct MC simulations across the studied energy and thickness ranges.
The derived analytical models provide efficient and accurate predictions of electron emission coefficients for SGEMP source terms, reducing the need for repeated MC simulations. The methodology is generalizable to other materials and supports rapid assessment of X-ray-induced electron emission in complex systems. Future work will explore machine learning techniques to further enhance computational efficiency for broader applications.
2025, 37: 106017.
doi: 10.11884/HPLPB202537.250195
Abstract:
Background Purpose Methods Results Conclusions
The performance of scintillation is directly related to the photoluminescence spectrum, scintillation luminescence time, etc.
In order to study the typical spectral response of the trihalide perovskite CH3NH3PbCl3 single crystal scintillator, the characteristic of differential luminescence spectrum response was found.
Perovskite monocrystalline samples were prepared by reversed-temperature crystal growth method. The differential luminescence spectra of CH3NH3PbCl3 were studied under different conditions, such as particle excitation, surface roughness and crystal temperature.
The experimental results show that both the surface roughness and the crystal temperature have obvious effects on the luminescence spectrum. And the perovskite crystal exhibits different scintillation luminescence time under X-ray and laser excitations, respectively.
The differential luminescence response has been discovered under several conditions. The results can play an important supplementary role in the applied research of perovskite scintillator in X-ray detection.
2025, 37: 106018.
doi: 10.11884/HPLPB202537.250222
Abstract:
Background Purpose Methods Results Conclusions
Delayed neutron, as a key signature of nuclear fission, plays a significant role in nuclear technology and engineering. Major nuclear reactor accidents (e.g., Chernobyl, Fukushima) are often accompanied by explosions, which generated shockwaves that may affece the transport of delayed neutrons and consequently influence the delayed neutron dose assessment. Understanding the influence of the shockwaves on the transport of delayed neutrons is critical for accurate radiological evaluation in such scenarios.
This study aims to investigate the influence of a shockwave on the transport of delayed neutron released from fission products and to calculate the resulting dose field at ground-level monitoring points.
A correspondence between mass thicknesses and delayed neutron doses was established by using the Monte Carlo method. The LAMBR model, based on a mirroring technique, was used to calculate the complex air density distribution arising by the shockwave at around the delayed neutron source. By combining the mass-thickness equivalent attenuation law with the LAMBR model, the delayed neutron dose fields of typical fission nuclides were calculated.
The results indicated that when the strength of the shockwave source is fixed, the enhancing effect of the shockwave on the transport of delayed neutrons becomes more pronounced as the source height increased. Conversely, when the source is close to the ground and the strength of the shockwave source is sufficiently strong, the ground-reflected shockwave may attenuate the transport of delayed neutrons.
The transport of delayed neutrons is significantly influenced by the shockwave, and furthermore the influence is closely related to the height and strength of the shockwave source. These findings provide valuable insights for improving dose assessment in accident conditions involving explosions.
2025, 37: 106019.
doi: 10.11884/HPLPB202537.250233
Abstract:
Background Purpose Methods Result Conclusions
Semiconductor laser devices (LDs) are a kind of laser with semiconductor material as its working material. LDs are the general name of optical oscillator and optical amplifier produced by photon excited emission caused by electron-optical transition in semiconductor material. LDs have the advantages of small volume, light weight, low power consumption, long life, simple structure, direct modulation and fast response. Thus, LDs are widely used as light source devices in the fields of optics communication, measurement, imaging, display, illumination, industrial processing, medical diagnosis, and so on.
With the application of LD in space optics communication, large hadron collider, nuclear industry, and other radiation environments, LDs operated in space radiation or nuclear radiation environment will suffer radiation damage. The reliability of LD-based optics communication system in radiation environment has attracted much attention. In view of the few reports on LD irradiation damage test methods at home and abroad, this paper mainly focuses on the radiation damage effects on the LDs used in radiation environment.
Referring to domestic and foreign standards, specifications and guidelines related to the radiation effects on the electronic components, combining LD irradiation damage test, radiation particle transport simulation and radiation effect simulation, and radiation damage mechanism analysis, the test methods of LD irradiation damage effect are studied from the aspects of irradiation source selection, test flow, irradiation bias conditions, etc.
The radiation test procedures for the LD displacement effect, ionization total dose effect, and transient dose rate effect are established respectively to form the test method of radiation damage effects on LDs.
The research provides the experimental technical supports for the evaluation of LD radiation damage and the test of LD radiation hardening.
2025, 37: 106020.
doi: 10.11884/HPLPB202537.250254
Abstract:
Background Purpose Methods Results Conclusions
Microreactors exhibit closely coupled neutronic-thermal-mechanical responses during operation, accompanied by highly non-uniform temperature distributions. Traditional on-the-fly cross-section generation methods, such as Doppler broadening in MCNP, are limited to the resolved resonance region and cannot handle temperature-dependent thermal neutron scattering laws (TSL), which are critical for thermal-spectrum systems.
To address this gap, this study aims to develop an on-the-fly TSL cross-section generation capability within MCNP based on statistical sampling, with a focus on thermal neutron scattering in high-temperature moderators such as ZrHₓ, and to enable high-fidelity neutronic-thermal coupling analysis in microreactor simulations.
A statistical sampling approach was implemented for on-the-fly computation of thermal scattering cross-sections. Multi-temperature cross-section evaluations were carried out for hydrogen in ZrHₓ, comparing discrete and continuous TSL treatments. The method was macroscopically validated through keff calculations in TRIGA and TOPAZ reactors. Furthermore, integrated neutronic-thermal coupling simulations were performed using unstructured-mesh MCNP coupled with ABAQUS.
The developed on-the-fly cross-section method produces keff values in good agreement with those obtained using pre-generated offline libraries. The integration with unstructured particle transport in MCNP allows spatially precise accounting for temperature feedback in the moderator region.
The new on-the-fly TSL capability enhances the accuracy of temperature-dependent neutronics modeling in thermal-spectrum microreactors. Coupled with unstructured meshing, it provides an essential foundation for high-fidelity multi-physics simulations of solid-state compact microreactors.
2025, 37: 106021.
doi: 10.11884/HPLPB202537.250223
Abstract:
Background Purpose Methods Results Conclusions
In small integrated reactors, the control rod drive mechanism (CRDM) is located within a high-intensity radiation field. The sealing coil of the CRDM may experience performance degradation due to intense irradiation, making accurate dose rate assessment essential for predicting maintenance cycles.
This study aims to evaluate the irradiation dose rate at the CRDM sealing coil in a small reactor during normal operation, identifying the main contributors to the dose rate.
Radiation source terms, including core fission neutrons and photons, fission and activated corrosion products in the primary coolant, and activation product N-16, were calculated. Computational models were developed using the Monte Carlo methods for photon transport and the point-kernel integration for dose rate evaluation. Conservative assumptions were applied to coolant density and source distribution.
The total dose rate at the CRDM sealing coil was found to be 4.1 Gy·h−1. N-16, produced via neutron activation in the coolant, was the dominant contributor, accounting for nearly the entire dose. Contributions from fission products, activated corrosion products, and core fission photons were negligible (less than 1%).
The irradiation dose rate at the CRDM sealing coil is primarily due to N-16 decay gamma rays, with the majority originating from coolant within a 1.5-meter thick region centered around the dose point. These results provide a basis for predicting coil lifespan and planning replacement intervals.
2025, 37: 106022.
doi: 10.11884/HPLPB202537.250220
Abstract:
Background Purpose Methods Results Conclusions
Extreme nuclear events typically generate intense explosions and release radioactive fission products. Gamma radiation from fission products, emitted during radioactive decay of fission products, can affect radiation dose fields for 10 μs to 15 s. During this period, the source intensity, spectrum, and spatial distribution exhibit significant temporal variations. Concurrently, shock-waves induce complex atmospheric density changes, creating hydrodynamic enhancement effects.
This study aims to develop a computational model for simulating time-varying fission product γ transport in non-uniform atmospheres perturbed by shock-waves, specifically quantifying the hydrodynamic enhancement effect on γ radiation dose fields.
A computational model for atmospheric density distribution was constructed using the LAMBR theory for shock-wave flow-field evolution. Based on radiation transport time-discrete theory, a transient variable-time-step Monte Carlo (MC) method was developed using the PHEN particle transport code.
A validation via 20 kt TNT-equivalent detonation simulations at 400 m altitude was conducted to evaluate the hydrodynamic enhancement effect of fission product γ of 235U. The results demonstrate that, compared to a uniform atmospheric model, the hydrodynamic enhancement effect can amplify the γ dose by 2—3 times at some locations.
The proposed transient variable-time-step Monte Carlo simulation method can effectively capture the hydrodynamic enhancement effect of the shock wave-perturbed atmospheric density field on the fission product γ radiation fields.
2025, 37: 106023.
doi: 10.11884/HPLPB202537.250247
Abstract:
Background Purpose Methods Results Conclusions
The investigation of radioactive source terms serves as a critical basis for formulating reactor decommissioning plans, estimating costs and schedules, and ensuring adequate radiation protection and emergency preparedness.
During neutron irradiation, reactor components undergo neutron activation reactions that generate significant quantities of radionuclides. The decay photons emitted by these nuclides constitute the primary source of radiation exposure for personnel during reactor decommissioning.
A combined approach using Monte Carlo particle transport programs (cosRMC, MCNP) and activation calculation programs (DEPTH, ALARA) was employed to calculate the nuclide atom density, activity, and radiation dose rates for key components after a specified operational period.
Comparing results from the two activation programs shows relative deviations within acceptable limits.
The comparison demonstrates the reliability and accuracy of cosRMC’s activation calculations and dose rate assessment capabilities for reactor decommissioning analysis.
2025, 37: 106024.
doi: 10.11884/HPLPB202537.250229
Abstract:
Background Purpose Methods Results Conclusions
Particle therapy is highly sensitive to respiratory motion, and low-latency respiratory gating is essential to ensure dose accuracy. Surface-guided radiation therapy (SGRT), featuring continuous monitoring and a non-ionizing workflow, is increasingly adopted in particle therapy and has become an important approach to respiratory gating. However, validation of gating latency for SGRT-guided proton and heavy ion systems remains limited in this area.
To measure the gate-on and gate-off latencies of an SGRT-proton and heavy ion radiotherapy system using two different methods, compare the two experimental approaches, and evaluate the latency performance of the SGRT-guided system to inform its clinical application.
Two measurements were conducted using a PPL film method and a high-speed camera-detector method. In the film method, a proton beam traversed a 1.5-mm-diameter aperture in a lead collimator, producing on the film a striped pattern that encodes latency; the films were digitized at 0.10 mm resolution for analysis. In the camera-detector method, a 240 frames/s high-speed camera recorded the instant the gating condition was met, and gate-on and gate-off delays were computed from the time difference to the detector-registered radiation signal. End-to-end latency was measured with both methods, and results were cross-validated using combined uncertainty.
The gate-on latency measured by the film method and the camera–detector method was 79 ms±10 ms and 67 ms±10 ms, respectively; the corresponding gate-off latency was 101 ms±9 ms and 129 ms±5 ms. Across two measurement methods, gate-on latencies were concordant within the combined standard uncertainty, whereas gate-off latency showed a significant method-dependent discrepancy, indicating systematic bias.
The SGRT-proton and heavy ion gating system meets our clinical requirements. This study demonstrates the feasibility and necessity of multi-method cross-validation of gating latency and provides quantitative evidence for the commissioning and acceptance test of SGRT in particle therapy.
2025, 37: 106025.
doi: 10.11884/HPLPB202537.250225
Abstract:
Background Purpose Methods Results Conclusions
Power equipment ports exhibit significant variations in characteristics, resulting in severe waveform distortion and low coupling efficiency, especially when operating at high voltages. Traditional testing methodologies in powered states present risks of system failures, complicating the evaluation of equipment resilience under such conditions. Notably, there is a lack of established testing methods or platforms for assessing the effects of high-altitude electromagnetic pulse (HEMP) on power equipment, both domestically and internationally.
This study aims to explore the physical interactions between power systems and HEMP current injection test systems, ultimately developing a novel testing method to evaluate the impact of HEMP on power equipment safely and effectively.
We propose a pulse disturbance loading method predicated on an equivalent "zero potential," which addresses significant limitations related to insulation withstand voltage and power capacity in existing pulse sources that struggle with power frequency voltages. The method allows for phase-controllable loading of nanosecond pulses onto millisecond-level power frequency signals. This approach enhances the coupling efficiency between the pulse source output and the power equipment, facilitating accurate measurements.
The implementation of this novel loading method successfully captures strong electromagnetic pulse phenomena and establishes threshold data for power equipment, simulating conditions closely aligned with real operational scenarios. This advancement significantly improves the reliability of test results in understanding equipment behavior under HEMP exposure.
The developed pulse disturbance loading method offers a promising solution for evaluating the effects of HEMP on power equipment, addressing previously encountered challenges in testing. This research contributes to the establishment of reliable testing protocols for assessing the resilience of power systems against HEMP threats, ultimately enhancing the safety and robustness of critical infrastructure.
2025, 37: 106026.
doi: 10.11884/HPLPB202537.250111
Abstract:
Background Purpose Methods Results Conclusions
As for the electromagnetic pulse (EMP) effect experiment in limited space or for the large system under test, the inverted V-shaped biconical-wire grating antenna based on typical structure may not meet the requirements.
In this paper, a novel horizontally polarized radiation-wave antenna deriving from the typical structure is proposed.
Firstly, a local refinement strategy is used to reduce the field leakage on the x axis near the center of the grating wires. In this way, the polarization component of the electric fields (E-fields) in this direction is enhanced and the field uniformity is improved at the same time. Secondly, the grating antenna is asymmetrically designed and the layout of the typical biconical-wire grating antenna in the +y direction is adjusted so as to provide enough space for adjustment.
Results show that the energy fed to the antenna can be redistributed by adjusting the layout of the wire grating antenna. Compared with the typical biconical-wire grating antenna, the polarized E-field component of the proposed antenna on x axis at (20, 0, 3.2) m is increased about 20% when the antenna is set up to 20 m high, and a working range about 20 m×20 m is provided. Meanwhile, the polarized E-field components in +y and 45° directions are reduced relatively rapidly. The E-field contour lines in +y direction of the new antenna are gradually compressed and converged to the antenna’s convergence points, looking like a rugby.
The feasibility and validity of the presented scheme have been tested by an antenna experiment, which also presents the characteristics of convenience for installation and maintenance.
2025, 37: 106027.
doi: 10.11884/HPLPB202537.250221
Abstract:
Background Purpose Methods Results Conclusions
High-altitude electromagnetic pulse (HEMP), generated by nuclear explosions at high altitudes, is characterized by an extremely high amplitude, broad pulse width, and extensive geographic coverage. It poses a severe threat to modern electronic systems, communication infrastructures, and power grids. Accurate and efficient prediction of the HEMP environment is essential for evaluating its potential impact and formulating protective measures.
Traditional numerical methods for HEMP prediction are often computationally intensive and time-consuming. This paper aims to develop a fast and accurate prediction model based on an artificial neural network (ANN) to overcome these limitations and enhance computational efficiency while maintaining prediction accuracy.
The proposed model integrates the Karzas–Latter high-frequency approximation model with the World Magnetic Model to establish a physical basis for HEMP simulation. A deep neural network architecture is constructed, comprising one input layer, eight hidden layers, and one output layer. The Sigmoid function is adopted as the activation function, and the mean squared error is used as the loss function during training.
Experimental results demonstrate that the ANN-based model can accurately predict the peak electric field intensity of HEMP across a wide area within a very short computation time. Compared with conventional numerical methods, the model significantly reduces the required calculation time while achieving high predictive accuracy, making it suitable for rapid environment estimation and scenario analysis.
The developed ANN model provides an efficient and reliable tool for fast prediction of the HEMP environment. It offers substantial practical value for HEMP risk assessment, emergency response planning, and design of protection strategies for critical infrastructure. The research outcomes can serve as a valuable reference for both academic and applied disciplines concerned with electromagnetic pulse effects.
2025, 37: 106028.
doi: 10.11884/HPLPB202537.250224
Abstract:
Background Purpose Methods Result Conclusions
Distribution transformers in the high altitude electromagnetic pulse (HEMP) conduction environment are subjected to nanosecond electrical stress, which can easily cause insulation failure or damage between the winding leads.
This paper takes the transformer winding model as the basis to study the relationship between the volt-second characteristics of oil-immersed paper, breakdown probability, pulse voltage amplitude, and cumulative number of withstand times with different half-height widths and rising edge of the nanosecond voltage pulses (U-N characteristics) .
Modify the circuit components to alter the output voltage’s half-width and rise time, thereby investigating the impact of these changes on the breakdown characteristics of oil-immersed paper. Apply the Weibull distribution function to fit and analyze the resulting data.
When the fixed rising edge is 20 ns, the breakdown voltage decreases as the half-height width increases; when the fixed half-height width is 500 ns, the breakdown voltage increases as the rising edge increases.
The effects of different voltage parameters on the volt-second characteristics and breakdown probability are more obvious, and it is found that the probability of breakdown of oil immersed paper wave head decreases with the increase of full width at half maximum, and increases with the increase of rising edge, resulting in changes in breakdown probability and volt-second characteristics. The change in U-N characteristics is more affected by the magnitude of voltage amplitude, and less affected by changes in voltage characteristic parameters.
2025, 37: 106029.
doi: 10.11884/HPLPB202537.250226
Abstract:
Background Purpose Methods Results Conclusions
As the most challenging issue in the field of the electromagnetic pulse effects, no uniform method of the system vulnerability assessment against the high-altitude electromagnetic pulse (HEMP) has been established. The system design, use and test organizations stand on the different perspectives and the different criteria, which lead to the severe discrepancy in the assessment results. On the other hand, the basic data come from several sources, such as the experience, testing, computation or, subjective judgements, and there is great uncertainty in these data. So the creditability of the assessment conclusions is vital to be validated from the objective and subjective information. However, the high cost and long duration will prohibit the conduct of the whole system test or computation, such as the communication and power infrastructures. Thus the assessment validation is a hard subject.
In this paper, vulnerability the of a computer control system to HEMP is taken as an illustration to validate the effectiveness of different assessment methods.
Here, three approaches relatively from the fields of the system use, design and test (i.e. risk analysis, electromagnetic compatibility (EMC) analysis and Bayesian networks (BN)) are adopted and independently evaluate the HEMP susceptibility of the item under test (IUT).
Three evaluation results indicate that the assessment methods are effective despite their different thoughts, emphasizes and knowledge fields.
The BN method can preferably respond to the inherent characteristic of HEMP effect assessments, such as the conductivity, uncertainty, synthesis and subjectiveness, so the BN method is potentially promising in the practices.
2025, 37: 106030.
doi: 10.11884/HPLPB202537.250235
Abstract:
Background Purpose Methods Results Conclusions
Light radiation, the primary mode of energy dissipation in nuclear explosions, profoundly impacts both the ecological environment and human society. A thorough understanding of its characteristics, propagation dynamics, and energy distribution is therefore essential for evaluating and protecting against nuclear explosion damage effects.
This study introduces the Kolmogorov-Arnold network (KAN) to construct an interpretable model for predicting the area of light radiation damage. The model utilizes multiple optimization algorithms to invert key source term parameters, namely the explosion yield, height of explosion, and explosion location.
Based on the theory of nuclear explosion fireballs, a light radiation model was developed and integrated with ArcGIS Pro software to visualize thermal energy distribution on real-world maps. A dataset correlating explosion yield and height with damage area was then generated, quantified according to established standards for biological burn injuries. The KAN was trained on this dataset, leveraging its unique advantage of providing explicit, interpretable formulas for prediction. To validate its efficacy, the KAN's performance was benchmarked against eight other algorithms, including Gated Recurrent Unit (GRU), Extreme Learning Machine (ELM), and Random Forest (RF). A loss function was constructed for the radiation model to facilitate the inversion of source term parameters via multiple optimization algorithms.
The results demonstrate that the KAN model achieves high prediction accuracy while yielding an interpretable formula for the damage area. Furthermore, both the genetic algorithm and the Hippopotamus optimization algorithm successfully inverted the nuclear source term parameters with high fidelity.
This methodology facilitates both the rapid prediction of damage effects and the accurate inversion of source parameters, thereby enhancing emergency response efficiency and aiding in strategic protective decision-making.
2025, 37: 106031.
doi: 10.11884/HPLPB202537.250207
Abstract:
Background Purpose Methods Results Conclusions
The Hefei Advanced Light Facility (HALF), as one of the world’s most advanced fourth-generation synchrotron radiation sources, has achieved remarkable improvements in beam brightness and coherence. However, these advances impose stricter requirements on radiation protection, and traditional shielding methods developed for third-generation facilities are insufficient, particularly in accounting for solid bremsstrahlung induced by the Touschek effect.
This study aims to establish a comprehensive framework for evaluating radiation sources at HALF beamline stations and to provide a reliable basis for shielding design.
Taking the BL10 beamline station as the case study, a multi-physics coupled simulation approach was developed: ELEGANT was used to model Touschek-induced beam losses, FLUKA was employed to simulate bremsstrahlung transport and energy deposition, and STAC8 was applied to calculate synchrotron radiation dose distributions.
The results indicate that the Touschek effect contributes significantly to overall radiation levels in fourth-generation light sources and cannot be neglected in shielding assessments. Moreover, the integrated framework enables systematic analysis of multiple radiation sources under complex geometry and operational transitions.
The proposed method has been successfully applied to the radiation assessment and shielding design verification of HALF beamline stations, and it also provides a valuable reference for radiation protection studies in new-generation synchrotron facilities.
2025, 37: 106032.
doi: 10.11884/HPLPB202537.250179
Abstract:
Background Purpose Methods Results Conclusions
The electron beam test platform, as the pre-research project of Shenzhen Superconducting Soft X-ray Free Electron Laser (S3FEL), will be used to overcome several major key technologies in high repetition frequency free electron laser.
Based on the previously proposed beam window (BW) design integrated into the beam dump, this study aims to conduct the radiation safety analysis and the thermo-structural analyses under non-ideal conditions during operation.
The radiation dose at the beam window was calculated and analysed using the Monte Carlo method. To evaluate the robustness of BWs during operation, the thermo-structural analyses were conducted using the finite element analysis method under non-ideal situations, including beam eccentricity, beam shrinkage, and reduced cooling water flow rate.
The results show that the radiation dose at 30 cm outside the side walls and ceiling complies with Chinese national standards, verifying the radiation safety of the scheme. Besides, the results indicate that beam eccentricity has negligible effects on the temperature, stress, and deformation of the beam window. Both beam shrinkage and reduced cooling water flow rate lead to increased temperature, stress, and deformation.
However, the standard deviation of the beam shrinkage must not fall below 10% of its original value, and the cooling water flow rate must not be lower than 0.2 m/s; otherwise, the safe operation of the beam window would be compromised. This paper clarifies the safety operation threshold for the beam window, providing a theoretical basis for its secure operation.
