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, Available online , 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 with 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 it 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, 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.
, Available online , 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 analysis 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 the 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.
, Available online , doi: 10.11884/HPLPB202537.250246
Abstract:
Background Purpose Methods Results Conclusions
Boron neutron capture therapy (BNCT) dose simulation is the cornerstone of 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.
Inside 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 22 cm depth in the tumour target the boron dose accounts for 80.9% of the total dose.
Developed within weeks and with low licence cost, the system provides an efficient calculation tool for BNCT dose simulation and a reference framework for BNCT dose simulation in research and education.
, 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/HPLPB202537.250109
Abstract:
Background Purpose Methods Results Conclusions
With the rapid development and application of tethered unmanned aerial vehicle (UAV) systems, the lightning strike risk faced by the tethered UAV systems has become a severe issue that can not be ignored. Compared with traditional UAVs, the presence of the tether cable in tethered UAV systems has brought significant changes to the potential lightning strike risks of them, and the relevant influencing factors on the lightning strike probability have also changed.
This study aims to investigate the lightning strike point distribution of typical tethered UAV system by combining electrostatic field analysis and numerical simulation. The goal is to present the lightning strike probability of different parts of the tethered UAV system and identify its main influencing factors.
The ANSYS finite element analysis software was used to analyze the electrostatic field distribution around the tethered UAV system under the background electric field of thunderstorm, and the lightning strike points with higher probability on the tethered UAV system were determined. On this basis, a numerical simulation assessment of lightning strikes on a typical tethered UAV system was carried out by employing the dielectric breakdown model and the sub-grid technology. The lightning strike probability distribution at different parts of the tethered UAV system was obtained, and the influence law of different factors on the lightning strike probability was presented.
The results of the numerical simulation show that the lightning strike probability of the tethered UAV system increases approximately linearly with the increase of the tethered height and the volume charge density of thundercloud. When the tethered UAV system is struck by lightning, the lightning strike probability on the end of the rotor arm is the highest, followed by the UAV fuselage, and the lightning strike probability on the tether cable is relatively low.
By combining electrostatic field finite element analysis with large-sample numerical simulation of lightning discharge, the lightning strike probability distribution characteristics of the tethered UAV system and the surrounding ground under different conditions are determined, which can provide a important reference for the direct lightning protection design of the tethered UAV system.
, Available online , doi: 10.11884/HPLPB202537.250134
Abstract:
Background Purpose Methods Results Conclusions
Autonomous navigation for Unmanned Aerial Vehicles (UAVs) is critical in Global Navigation Satellite System (GNSS)-denied scenarios, particularly within complex electromagnetic environments. Conventional Terrain Aided Navigation (TAN) systems often rely on single-modality sensors, making them susceptible to targeted interference that can degrade feature data and lead to positioning failure. Although multimodal feature fusion has shown potential for enhancing robustness, existing methods often impose significant computational overhead, limiting their suitability for real-time UAV applications.
This study aims to develop a robust and computationally efficient terrain matching algorithm that enhances resilience against electromagnetic interference, mitigates fusion bias caused by disparate feature scales, and improves search efficiency to meet real-time operational requirements.
The proposed algorithm integrates a dual-modality feature fusion framework. Rotation Invariant Uniform Local Binary Pattern (RIULBP) features are extracted from Synthetic Aperture Radar (SAR) imagery to capture noise-resistant spatial textures, while Frequency Energy Distribution (FED) features are derived from Digital Elevation Models (DEM) to represent global terrain structure. A dynamic weighting method based on feature sensitivity is employed to fuse these heterogeneous features, with Z-score normalization used to standardize their scales. The fused Canberra distance serves as the similarity metric for terrain matching. Particle Swarm Optimization (PSO) replaces the conventional sliding-window search, enabling efficient identification of the optimal match within the search area.
Experimental evaluations on a diverse dataset, including mountains, plains, and deserts, demonstrated that the proposed algorithm achieved a matching success rate consistently above 90%, outperforming single-modality and fixed-weight fusion methods. The algorithm also exhibited strong robustness in anti-interference tests, where Gaussian, speckle, and impulse noise were injected into SAR images, achieving up to a 30% improvement in matching success rate compared to single-modality approaches. Additionally, the PSO-based search significantly reduced computational time compared to exhaustive search methods.
The proposed algorithm provides an effective solution for UAV autonomous navigation in challenging environments. By combining spatial-domain (RIULBP) and frequency-domain (FED) features through a dynamic weighting strategy, the algorithm enhances robustness against electromagnetic interference while maintaining computational efficiency. The integration of PSO further ensures real-time applicability, validating the effectiveness of multimodal fusion and intelligent optimization for reliable UAV positioning.
, Available online , doi: 10.11884/HPLPB202537.250153
Abstract:
Background Purpose Methods Results Conclusions
In complex electromagnetic environments, electronic devices face risks of strong electromagnetic interference, performance degradation and even damage. Accurate acquisition of internal electromagnetic field distribution is a core prerequisite for analyzing field coupling mechanisms, revealing effect principles and evaluating system safety. Traditional metal electric field probes, due to large size and significant disturbance to the measured field, fail to meet fine measurement needs; electro-optic crystal technology, though with low-disturbance advantage, lacks sufficient sensitivity and frequency selectivity in the GHz band. Rydberg atom-based quantum microwave sensing technology, featuring self-calibration, SI unit traceability and high sensitivity, provides a new solution to the above problems.
To address the defects of traditional measurement technologies, verify the low-disturbance property of quantum microwave sensing technology, establish an accurate method for measuring internal electric fields of devices, realize high-resolution electromagnetic field distribution mapping, and provide technical support for the analysis and evaluation of complex electromagnetic environment effects.
The FDTD algorithm was used to compare field disturbance differences between metal probes and Rydberg atomic vapor cells; an experimental system centered on a cesium atomic vapor cell was built, combining electromagnetically induced transparency (EIT) spectroscopy and atomic superheterodyne technology. 45 measurement points with 2cm intervals were set in a square metal shell-simulated device to complete electric field measurement and data processing.
This technology caused minimal disturbance to the measured field, with measurement resolution reaching the millimeter level (<2 mm); in the simulated device, the maximum field intensity was 14.62 mV/m and the minimum was 1.66 mV/m. It had better frequency selectivity than electro-optic crystal technology, and low-field measurement could effectively reduce device damage risks.
Quantum microwave sensing technology can make up for the shortcomings of traditional technologies. Although high-field real-time monitoring requires combining with spectrum matching and its instantaneous bandwidth is narrow, its engineering application feasibility has been verified. Future research can focus on developing simplified measurement schemes for high-field scenarios.
, Available online , doi: 10.11884/HPLPB202537.250145
Abstract:
Background Purpose Methods Results Conclusions
With the advancement of electronic reconnaissance, communication, and radar technologies, direction-finding systems are facing increasingly higher demands for high precision, wide frequency coverage, large dynamic range, and real-time performance.
To address these developmental needs of direction-finding systems, this paper aims to design an ultra-wideband array direction-finding system. The objectives include achieving key specifications such as a frequency range of 20 MHz to 40 GHz, a maximum instantaneous bandwidth of 1 GHz, and a direction-finding accuracy better than 5 degrees across the entire frequency band, adapting to wide-range usage scenarios in communication, radar, and other fields.
The ultra-wideband array direction-finding system employs a spatial spectrum direction-finding mechanism. This is realized through the detailed design and implementation of hardware components, including a multi-channel direction-finding receiver and a multi-layer antenna array, along with software implementation based on spatial spectrum direction-finding algorithms.
The designed ultra-wideband array direction-finding system achieves an ultra-wide frequency range of 20 MHz to 40 GHz, supports direction-finding tasks with a maximum instantaneous bandwidth of 1 GHz, delivers a direction-finding accuracy better than 3 degrees across the entire band, and possesses the capability to handle three or more same-frequency signals simultaneously.
The ultra-wideband array direction-finding system significantly enhances core performance parameters such as frequency range, instantaneous bandwidth, and direction-finding accuracy. Systems with similar architectures have been successfully deployed in multiple large-scale projects, demonstrating their feasibility and scalability through practical applications.
, Available online , doi: 10.11884/HPLPB202537.250126
Abstract:
Background Purpose Methods Results Conclusions
With the increasing complexity of electromagnetic spectrum, efficient signal modulation identification algorithm is beneficial to electromagnetic spectrum management, which is very important for modern communication system. However, traditional algorithms have limitations in feature extraction and lack of accuracy.
This paper presents an improved algorithm for electromagnetic signal modulation recognition. This algorithm integrates the temporal convolution network (TCN), the bidirectional long-short-term memory (Bi-LSTM) network, and the improved locality-sensitive hashing attention mechanism (LSH Attention) to enhance the accuracy of recognition.
Firstly, Bi-LSTM is designed to capture the bidirectional dependency of time series data and enhance the discrimination ability for complex modulation modes. Secondly, TCN and Bi-LSTM are fused through a cascaded architecture to achieve hierarchical time series feature extraction and bidirectional dynamic modeling. Finally, LSH Attention is added to reduce the complexity of the attention matrix while improving the recognition accuracy. In terms of data preprocessing, a KNN-BH processing method is proposed, which can improve the extraction accuracy of spectral features.
Experimental results on the RML2016.10a dataset show that compared with seven baseline algorithms, the TCN-LSTM-LSH Attention algorithm has the best recognition performance, with an overall recognition accuracy of 64.71% for 11 types of signal modulations.
This algorithm demonstrates great potential in electromagnetic spectrum applications and is highly suitable for use in high-precision modulation recognition tasks in communication systems.
, 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/HPLPB202537.250151
Abstract:
Background Purpose Methods Results Conclusions
In the design process of microwave absorbing structures, due to the larger wavelength of low-frequency electromagnetic waves, the thickness of the corresponding absorbing body will also increase. Therefore, achieving low-frequency broadband absorption in the microwave band with a thin thickness is a challenge.
To address the technical bottleneck of limited bandwidth in thin microwave absorbing materials at low frequenciesthis study proposes a new absorbing body design scheme based on a double-layer magnetic medium and mortise structure, focusing on breaking through the constraint relationship between material thickness and absorption bandwidth to achieve efficient absorption of electromagnetic waves in the L/S frequency bands.
The metamaterial is constructed with a double-layer structure using magnetic material, combined with surface periodically arranged mortise-type metal resonant units, and utilizes the synergistic effect of magnetic loss and structural resonance to enhance electromagnetic energy dissipation.
Simulation results show that within the working frequency band, there are two absorption peaks at f1=1.36 GHz and f2=2.29 GHz, and the absorption rate exceeds 90% in the 1.16-2.82 GHz frequency band, effectively covering the L band and extending to part of the S band. Under thin-layer conditions, it achieves a wideband absorption of 1.66 GHz, resolving the inherent contradiction between thickness and bandwidth of low-frequency absorbing materials.
The novel metamaterial absorber based on double magnetic media and mortise structure can provide a feasible solution for the engineering application of the next-generation thin broadband absorbing bodies.
, Available online , 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 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 < 5×10−6 at a 100 keV energy threshold. Experimental results indicated the detector's pulse height spectrum matched the simulated energy deposition. After background subtraction, its detection efficiencies for 1.8 Å, 2.9 Å, and 4.8 Å 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.
, Available online , 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: 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 combined 4He gas scintillator is proposed, which has the advantages of flat neutron energy response and high n/γ resolution, and 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 on 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 conforms to the expected targets.
, 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/HPLPB202537.250220
Abstract:
Background Purpose Methods Results Conclusions
Extreme nuclear events typically generate intense explosions and release radioactive fission products. Fission product γ, emitted during radioactive decay of fission products, can affect radiation dose fields for 10−5 to 15 seconds. 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.
, Available online , 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.
, Available online , 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 of 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.
, Available online , 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 Monte Carlo methods for photon transport and 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.
, Available online , 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 experiential, testing, computation or the 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, too high cost and too long term 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, the computer control system vulnerability for 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. The risk analysis, electromagnetic compatibility (EMC) analysis and the 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 in despite of 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.
, Available online , doi: 10.11884/HPLPB202537.250201
Abstract:
Background Purpose Methods Results Conclusions
In near-field pulsed neutron measurements (＜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 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 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 source-to-detector distance ＜80 cm significantly impacts sensitivity, with an 8.44% correction factor at 20 cm; experiments validated simulation accuracy.
This method effectively mitigates sensitivity deviation, clarifies the inverse-square law’s limitations under close proximity, extends calibration scope, and provides a new technical pathway for precise neutron metrology in harsh environments like pulsed reactor transient diagnostics and fusion devices.
, Available online , 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 kilometers, 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 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.
, Available online , 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 shockwave that may affects the transport of delayed neutron and consequently influence delayed neutron dose assessment. Understanding the influence of the shockwaves on the transport of delayed neutron is critical for accurate radiological evaluation in such scenarios.
This study aims to investigate the influence of 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 Monte Carlo method. The LAMBR model, based on a mirroring technique, was used to calculate the complex air density distribution arised by shockwave at around the delayed neutron source. By combing 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 neutron becomed 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, ground-reflected shockwave may attenuate the transport of delayed neutron.
The transport of delayed neuron was significantly influenced by the shockwave, furthermore the influence is closely related to height and strength of the shockwave source. These findings provided valuable insights for improving dose assessment in accident conditions involving explosions.
, Available online , 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 simulation, 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～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.
, Available online , doi: 10.11884/HPLPB202537.250075
Abstract:
Background Purpose Methods Results Conclusions
Electromagnetic pulses (EMPs) can couple into electronic equipment cavities through apertures, causing severe interference and potential damage. Understanding the coupling characteristics and resonance mechanisms is critical for improving electromagnetic protection design.
This study aims to investigate the coupling effects of EMPs on rectangular cavities with apertures, focusing on field distribution, resonance behavior, and the impact of incidence conditions.
A numerical model of a perfectly conducting rectangular cavity was established using the Finite-Difference Time-Domain (FDTD) method. The study analyzed electromagnetic field distributions inside the cavity under varying incidence angles and continuous pulse excitations. A time-frequency joint analysis method was applied to reveal the resonance mechanisms of aperture coupling.
The results show that aperture coupling produces significant electric field enhancement at specific frequencies, with peak amplitudes several times larger than the incident field. Normal incidence yields the strongest resonant effects, while oblique incidence leads to different responses in electric field components due to boundary constraints. Continuous pulse excitation results in electric field energy accumulation, though limited by standing-wave effects. The resonant frequencies were found to be strongly dependent on cavity dimensions, confirming the frequency-selective characteristics of aperture coupling.
This research establishes the theoretical basis for understanding EMP aperture coupling and provides technical references for designing protection measures in high-intensity electromagnetic environments.
, Available online , doi: 10.11884/HPLPB202537.250111
Abstract:
Background Purpose Methods Results Conclusions
As for the electromagnetic pulse (EMP) effect experiment in limited space or for large under test system, 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, local refinement strategy is used to reduce the field leakage on 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 typical biconical-wire grating antenna in +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, and a work range about 20 m×20 m is provided. Meanwhile, the polarized E-field components in +Y and 45° directions are reduced relatively fast. The E-field contour lines in +Y direction of the new antenna are gradually compressed and converged to the antenna’s convergence points, looking as a rugby.
The feasibility and validity of the presented scheme has been tested by antenna experiment, which also presents the characteristics of convenience for installation and maintenance.
, Available online , doi: 10.11884/HPLPB202537.250122
Abstract:
Background Purpose Methods Results Conclusions
Pulse drive sources are a critical component 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, requiring relatively low insulation, making 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 (coupling coefficient >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 × 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, higher-performance compact pulse drive sources.
, Available online , doi: 10.11884/HPLPB202537.250107
Abstract:
Background Purpose Methods Results Conclusions
The operational reliability of Unmanned Aerial Vehicles (UAVs) is critically dependent on their Global Navigation Satellite Systems (GNSS). However, in increasingly contested electromagnetic environments, the inherent weakness of GNSS signals makes them highly susceptible to suppression jamming, leading to performance degradation or mission failure. Existing test standards often focus on single-jammer, static scenarios and lack the quantitative rigor needed to assess the performance of advanced multi-element antenna systems under complex, dynamic conditions.
This research aims to address this gap by developing and validating a standardized, quantitative test methodology for evaluating the anti-suppression-jamming performance of UAV GNSS systems. The objective is to create a reproducible framework that can simulate dynamic, multi-source interference and provide a comprehensive assessment from the RF front-end to the complete system level.
A hybrid test methodology integrating direct Radio Frequency (RF) injection and over-the-air (OTA) spatial irradiation was established within a microwave anechoic chamber. This “injection-irradiation” approach facilitates a full-link evaluation. Both static and dynamic tests were conducted on a seven-element GNSS adaptive array receiver. Static tests involved assessing performance against an increasing number of jammers (one to six) from fixed spatial locations. Dynamic tests simulated UAV maneuvers by placing the receiver on a turntable rotating at 2°/s, exposing it to a changing interference geometry. Performance was quantified by the jamming-to-signal (J/S) ratio threshold, carrier-to-noise ratio, and positioning success rate.
Static tests quantified a distinct saturation effect on the receiver’s spatial filtering capability; the J/S ratio threshold for positioning failure decreased from 106 dB against a single continuous-wave jammer to 60 dB against six broadband noise jammers. Critically, dynamic tests revealed a complex spatio-temporal coupling effect. In the six-jammer scenario, the system maintained a 100% positioning success rate at a J/S ratio of 70 dB while rotating, paradoxically outperforming its 60 dB static failure threshold. This demonstrates that the constant change in interference geometry can prevent the algorithm from settling into a worst-case nulling solution.
The proposed combined injection-irradiation and dynamic test methodology provides a robust and standardized framework for the quantitative assessment of UAV GNSS anti-jamming capabilities. The findings reveal that static tests alone are insufficient for predicting performance, as dynamic conditions can fundamentally alter the system’s response to multi-source interference. This research offers a critical tool for the realistic evaluation, design optimization, and validation of navigation systems intended for operation in complex electromagnetic environments.
, Available online , doi: 10.11884/HPLPB202537.250127
Abstract:
Background Purpose Methods Results Conclusions
With the increasing application of rotorcraft drones in fields such as airborne detection of thunderstorm electromagnetic fields, their operational safety in near-lightning environments has drawn widespread attention. The intense electromagnetic pulses generated by nearby lightning strikes can induce coupled currents in the internal cables of drones, thereby posing a risk of damage to the drone system.
This paper aims to investigate the electromagnetic coupling effects of nearby lightning pulse electromagnetic fields on the internal cables of rotorcraft drones and to evaluate and analyze the induced currents generated on different functional modules.
By simulating near-lightning pulse electromagnetic field environments experimentally, under various conditions including electric field strengths of 240 kV, 280 kV, and 320 kV, and magnetic field strengths ranging from 80 to 1600 A/m, induced current measurements were conducted on key internal cables connected to the motor, electronic speed controller (ESC), flight control module, GPS, and receiver.
The experimental results show that under pulsed electric fields, all tested cables exhibited significant induced currents, with the highest peak current of 12 A occurring between the motor and the ESC. Pulsed magnetic fields mainly induced currents during the voltage signal rise phase, reaching a peak value of 0.18 A under the 1600 A/m condition.
When operating in a near-lightning environment, drones generate induced currents, which pose certain risks to their normal operation. Therefore, certain protective measures are necessary for critical modules such as GPS and key cables. Owing to time constraints, this study did not further analyze the impact of near-lightning electromagnetic environments on data links, and the influence of drone cable layout on induced currents warrants further investigation.
, Available online , doi: 10.11884/HPLPB202537.250205
Abstract:
Background Purpose Methods Results Conclusions
Modern battlefields are increasingly characterized by complex electromagnetic environments (EME), posing significant challenges to unmanned aerial vehicle (UAV) operational effectiveness.
To address this issue, this study aims to quantitatively evaluate how complex EME affects UAV operational effectiveness using a multi-level framework, incorporating defined key metrics including anti-jamming capability verification.
A three-tier evaluation model was developed, incorporating EME complexity, subsystem performance, and operational capabilities. EME complexity was characterized by four metrics weighted via AHP. Critical subsystem indicators—such as communication reliability and navigation accuracy—and operational capabilities like mission execution and anti-jamming performance were causally mapped within an environment-effectiveness mapping. This mapping enabled the model to be normalized and integrated using sensitivity coefficients, and stochastic jamming scenarios were simulated in MATLAB to validate the approach.
The results demonstrated a distinct negative exponential relationship between EME complexity and operational effectiveness. Performance declined progressively with intensified EME, but notably, UAVs equipped with advanced anti-jamming systems maintained higher effectiveness under identical conditions.
This study confirms the critical importance of anti-jamming technologies in preserving UAV combat capability in complex EME, the evaluation framework offers practical insights for developing robust UAV systems suited to contested electromagnetic spectra.
, Available online , 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.
, Available online , 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 on 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.
, 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/HPLPB202537.250161
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 has been generated by the PLL and directly routed through the MRCC pin. After completing the impedance matching, the RF signal has been processed via differential circuit to obtain the required simulated beam signals. Then, the required signals have been amplified using the RF amplifier. After the 1:4 power division, beam signals with four adjustable amplitudes output channels have been acquired finally. The trigger signal has been supplied directly from the FPGA I/O pins configured for LVCMOS33 operation at 3.3V, to meet the required LVTTL of BPM electronics.
Based on the beam current characteristics of the HEPS storage ring, we have tested the beam signal simulation performance of HEPS storage ring with a frequency of 220kHz and different patterns during the experiment. In addition, the simulation performance of the single trigger signal and BEPCII collision zone with a frequency of 1.21MHz 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 have tested the pattern dependence of HEPS BPM electronics with this signal source. The results showed that there is no pattern dependence effect in the HEPS BPM electronics used in this experiment.
This signal generator could be used to assist the logical design and correctness of DBPM, as well as the debugging of the data transmission and control logic between the DBPM and FOFB, and testing the latency of the FOFB system. Based on this system, the debugging difficulty of BPM and FOFB systems could be reduced and accelerating the deployment of the FOFB system.
, Available online , 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 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 robust of BWs during operation, the thermo-structural analyses was 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 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.
, 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.
, Available online , doi: 10.11884/HPLPB202537.250141
Abstract:
Background Purpose Methods Results Conclusions
As a kind of equipment in the field of electromagnetic compatibility testing, the application research of reverberation chamber covers airborne platforms, electronic and electrical equipment, automotive electronic components, etc. At present, the demand for radiation susceptibility testing in military and civil standards using reverberation chamber is growing, but there are significant differences in test standards, and the requirements of key indicators (such as frequency range, waveform characteristics, field uniformity, etc.) are not unified, which restricts the accuracy of product verification in high field strength environment.
The purpose of this study is to systematically analyzes the radiation susceptibility test standards and methods of reverberation chamber in different standards, reveals the limitations of existing standards, and puts forward the solution of military and civil standards collaborative optimization, which provides the basis and guidance for product design verification.
Through standard comparison, focus on the following two research paths: first, standard comparison, sort out the domestic test standards for airborne platforms, electronic and electrical equipment, automotive electronic components, etc; second, parameter analysis, show the differences of key indicators such as frequency range, waveform characteristics, field uniformity, etc.
First, standard difference. the test frequency range of military products is higher than that of civil fields, such as 40GHz; The requirements for waveform characteristics of military products and electronic and electrical equipment are simpler than others; Military products and electronic and electrical equipment require higher field uniformity (in the low frequency band) than other requirements, which is 2dB higher. Second, parameter influence. the difference in the test frequency range may lead to inconsistent sensitivity response in the high frequency band of the product; Different waveform characteristics lead to inconsistent response of products to different waveforms; The difference of field uniformity leads to the difference of construction cost of reverberation chamber.
It is suggested to promote the unification of key indicators of military and civilian standards, establish a standardized field strength evaluation system, and optimize military test standards. The research results can help product designers accurately grasp the key points of design verification under high field strength environment and improve the efficiency of R&D.
, 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.
, Available online , doi: 10.11884/HPLPB202537.250149
Abstract:
Background Purpose Methods Results Conclusions
Unintended spectral leakage from high-power linear frequency-modulated (LFM) radar can seriously degrade adjacent QPSK communication links.
To clarify the effects of key LFM waveform parameters on interference mechanisms and to describe their governing patterns,
this study develops a closed-loop injection platform based on software-defined radio (SDR) 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 offer design insights into multi-channel TWTs and simultaneously enhance 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, with 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/HPLPB202537.250066
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/HPLPB202537.250211
Abstract:
Background Purpose Methods Results Conclusions
The 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 exit in the point spread function (PSF) of radiation imaging system, 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. An experimental measurement of the low-frequency components is challenging because of the 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 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 is 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 orders below the peak of PSF. Experiments shown 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%～62%.
The ring- aperture method provides a reliable experimental approach for measuring low-frequency components of 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.
, Available online , doi: 10.11884/HPLPB202537.250206
Abstract:
This paper conducts an equivalence study on honeycomb structures with dispersion characteristics and anisotropy based on an improved S-parameter inversion method. Using three-dimensional electromagnetic simulation software CST and a free-space measurement system, the modeling, simulation, and practical testing of the honeycomb structure and its equivalent flat plate were successfully accomplished. By varying the incident angle of the plane wave, the scattering parameters of the honeycomb model were obtained under both normal and oblique incidence conditions. Through an inversion procedure, the equivalent electromagnetic parameters corresponding to each incident condition were sequentially derived and subsequently applied to the equivalent homogeneous flat plate, thereby achieving the equivalency treatment of the honeycomb structure. The accuracy and feasibility of this method are verified by comparing the simulation and measurement results of scattering parameters before and after the equivalence of the honeycomb structure.
This paper conducts an equivalence study on honeycomb structures with dispersion characteristics and anisotropy based on an improved S-parameter inversion method. Using three-dimensional electromagnetic simulation software CST and a free-space measurement system, the modeling, simulation, and practical testing of the honeycomb structure and its equivalent flat plate were successfully accomplished. By varying the incident angle of the plane wave, the scattering parameters of the honeycomb model were obtained under both normal and oblique incidence conditions. Through an inversion procedure, the equivalent electromagnetic parameters corresponding to each incident condition were sequentially derived and subsequently applied to the equivalent homogeneous flat plate, thereby achieving the equivalency treatment of the honeycomb structure. The accuracy and feasibility of this method are verified by comparing the simulation and measurement results of scattering parameters before and after the equivalence of the honeycomb structure.
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 in the various layers of the system surface or internal photoelectron or Compton electrons, and excitation of electromagnetic pulse, 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.
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/HPLPB202537.250183
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
