HIRF Research Articles

Development of a silicon carbide radiation detection system and experimentation of the system performance

Silicon carbide (SiC) detectors have excellent radiation detection capabilities for various radiation particles, including high energy resolution, fast response times, and good radiation resistance. A SiC radiation detection system was developed to measure the neutron fluence rate and the γ-ray dose rate in high intensity radiation fields. The system was composed of two SiC detectors, a temperature monitor, two preamplifiers for each SiC detector, a data acquisition unit with two signal channels, three pairs of communication devices, and an application software to analyze and visualize the measurement data. The two SiC detectors were fabricated based on two kinds of 4H-SiC diodes and used to respectively respond to neutrons and γ-rays. Repeated experiments showed that the two SiC detectors of the system can respond to α-particles, neutrons, and γ-rays. To verify the performance of the SiC detection system, including the response linearity of the neutron fluence rate, the measurement range of the γ-ray dose rate, and the radiation resistance of the SiC radiation detectors, the system was tested in multiple neutron and γ-ray fields. The tests results show the system can measure the neutron fluence rate from 5.64 × 10 2 cm−2 s−1 to 1.03 × 10 5 cm−2 s−1 with excellent linearity response, and the γ-ray dose rate from 0.005 Gy/h to 20 Gy/h. Furthermore, the SiC detectors demonstrated good radiation resistance. The neutron and γ-ray radiation field can still be measured stably by the system after exposure to neutron fluence of 1.07 × 10 14 cm−2 and γ-ray dose of 3.52 × 10 4 Gy. This work is the preliminary research to continue the exploration how to measure the n/γ hybrid fields accurately using SiC detectors considering the different energy of neutrons.

Electromagnetic reverberation characteristic of chamber in high intensity radiation field test

Electromagnetic reverberation characteristic of chamber in high intensity radiation field test

TW-scale few-cycle short-wave infrared laser based on nonlinear compression in a large-core gas-filled hollow core fiber

In this Letter, we present the generation of terawatt-scale few-cycle short-wave infrared (SWIR) lasers using nonlinear compression in a large-core gas-filled hollow core fiber. Through the experimental verification, we investigate the energy scaling properties and nonlinear pulse propagation in the argon-filled hollow core fiber. At static pressure, the system delivers pulses with 5.55 mJ/9.04 fs at a central wavelength of 1.45 μm, resulting in a peak power of about 0.5 TW. Subsequently, based on the chirped input pulses and pressure gradient, the system delivers terawatt-scale two-cycle SWIR pulses with 9.52 mJ/10.65 fs, resulting in a record peak power of about 0.7 TW. This study marks a crucial advancement in the field of SWIR ultra-intense, ultrashort pulse nonlinear interaction platforms. This high-energy, few-cycle SWIR source has significant applications in high-intensity THz radiation, x-ray generation, and other fields of strong-field physics.

Thermal breakdown characteristics and damage mechanisms of novel GaN HEMT aviation nanodevices in high-intensity radiation fields

Thermal breakdown characteristics and damage mechanisms of novel GaN HEMT aviation nanodevices in high-intensity radiation fields

Experimental Realization of Auger Decay in the Field of a Positive Elementary Charge.

Auger electron spectroscopy is an omnipresent experimental tool in many fields of fundamental research and applied science. The determination of the kinetic energies of the Auger electrons yields information about the element emitting the electron and its chemical environment at the time of emission. Here, we present an experimental approach to determine Auger spectra for emitter sites in the vicinity of a positive elementary charge based on electron-electron-electron and electron-electron-photon coincidence spectroscopy. We observe a characteristic redshift of the Auger spectrum caused by the Coulomb interaction with the charged environment. Our results are relevant for the interpretation of Auger spectra of extended systems like large molecules, clusters, liquids, and solids, in particular in high-intensity radiation fields which are nowadays routinely available, e.g., at x-ray free-electron laser facilities. The effect has been widely ignored in the literature so far, and some interpretations of Auger spectra from clusters might need to be revisited.

Continual Residual Reservoir Computing for Remaining Useful Life Prediction

In practical engineering applications, it is inevitable that the production is often faced with different working conditions. Therefore, it is necessary to have a continual learning system, which can adapt to a sequence of tasks and keep learning over the time. In this work, we propose a continual deep residual reservoir computing (DRRC) framework for the practical remaining useful life (RUL) prediction task. Specifically, we propose a novel deep echo state network structure with residual blocks to effectively mitigate the performance degradation of the deep reservoir computing framework and reduce the difficulty of model training. Further, the proposed framework is trained with the elastic weight consolidation (EWC) method to alleviate the impact of catastrophic forgetting in continual learning systems. Extensive experiments are conducted with the FEMTO-ST bearing and high intensity radiated fields (HIRF) battery dataset. And the proposed framework is proved to be effective in multiple continual learning tasks comparing with other state-of-the-art methods.

Approximation of High Intensity Radiated Field by Direct Current Injection using matrix methods based on Characteristic Mode Analysis

Abstract. This contribution discusses the approximation of radiated by conducted immunity tests by the example of High Intensity Radiated Field (HIRF) and Direct Current Injection (DCI) based on a surface current analysis. For this purpose, Characteristic Mode Analysis (CMA) is applied to provide basis functions for a surface current expansion in Characteristic Modes. Via a matrix-based basis transformation algorithm involving Characteristic Mode data of both HIRF and DCI test setups, suitable DCI surface currents are derived. The approximation of HIRF surface currents by the computed DCI surface currents is analyzed for exemplary DUTs over a broad frequency range. Within this frequency range, those DCI frequencies leading to an optimal approximation of the HIRF current are determined. Concerning practical issues in DCI testing, the influence of DCI adapter parameters on the surface current approximation is elucidated. The numerical results show that DCI can approximate HIRF at low frequencies largely independent from the DCI adapter setting, whereas at high frequencies an approximation is difficult to realize.

Research on the Coupling Effect of HIRF on UAV

The electromagnetic environment of low-altitude airspace has become extremely complex due to the rapid advancement of radio technology. In particular, the electromagnetic energy of HIRF (High Intensity Radiation Field) that is frequently emitted by radar, radio stations, radios, and various ships/airborne impacts negatively aircraft flight safety. In this paper, based on the modeling of a consumer UAV, the HIRF effect is simulated using UWB-HPM, and the electric field variation law at key position and antenna coupling law of the UAV under plane wave irradiation in different directions are analyzed with the help of CST simulation software. The results show that for front-door coupling, the shorter the pulse width of the interference signal is, the stronger the interference for the antenna is, while for back-door coupling, irritation direction and pulse width play a significant role in the coupling effect.

The XYU-GEM: Ambiguity-free coordinate readout of the Gas Electron Multiplier

We describe the development of a position-sensitive Gas Electron Multiplier detector prototype, providing for each ionizing event three coordinates: the cartesian X and Y, and U at 45°. Simultaneous recording of the three projections permits ambiguity-free reconstruction of multiple tracks, and aims at operation in very high intensity radiation fields.

Low Profile Dynamic Patch Antenna Array With High-Intensity Radiation Fields (HIRF) Protection

A 1-bit low-profile patch antenna array integrating beam scanning and adaptive high-intensity radiation fields (HIRF) protection is proposed in this paper. Each antenna element consists of two dielectric layers, two radiation patches, a ground plane, and a feeding network. By electronically controlling a pair of coding diodes in the same direction, the antenna element can achieve 180 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> phase difference, producing two logical states, namely “0” and “1”. It has good beam scanning capability in the range of −60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> to 60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> . When the proposed antenna is exposed to HIRF, the protective diodes mounted over the grounded coplanar waveguide (GCPW) transmission line are triggered, dramatically reducing the overall gain of the antenna array. By optimizing design, the element possesses a bandwidth of 8.8 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 9.3 GHz. The grating lobe of the antenna array is suppressed by 17.5 dB thanks to the adoption of the non-uniform feed. The simulation results indicate that the proposed antenna element and array have a high isolation degree of 22.4 dB and 23.2 dB when exposed to HIRF, respectively. Finally, a prototype of the antenna is fabricated, and the validity of the proposed design is experimentally verified. The experimental results are in good agreement with the simulation results, demonstrating the validity of the proposed design.

Design of a Quasi-TEM Waveguide for the High-Intensity-Field Measurement of the Field-Induced Metasurfaces

Field-induced metasurface is an applicable technique to prevent the high-intensity-radiated-field (HIRF). To improve the measurement accuracy, this article presents the design of a waveguide that forms high-intensity TEM waves within its closed transverse boundaries. The proposed quasi-TEM waveguide adopts two artificial magnetic conductors (AMCs) on the sidewalls of a standard rectangular waveguide. And the construction of the AMC is based on the theory of high impedance surface (HIS), which performs perfect magnetic conductor (PMC) properties at its resonant frequency. Then, a prototype is designed and fabricated to measure the electric field distributions and demonstrate the theoretical analysis and simulation. The measurement results indicate that the proposed waveguide could realize a 1 dB rippled electric-field distribution in more than 90% region, compared to that of 30% in the standard waveguide. Finally, high-intensity-field measurements of a field-induced sample, energy selective surface (ESS), are compared in the proposed waveguide and a standard waveguide. The comparison result has proved that the proposed waveguide could better evaluate the HIRF performance of the field-induced metasurface.

Unshielded Two-Wire Circuit Systems under Weak Unbalance for High-Intensity Radiated Field Radiated Susceptibility by Double Bulk Current Injection

In unshielded two-wire circuits of weapon systems, the equipment at both ends of the cable needs to be tested at the same time. The theoretical model of substituting double bulk current injection (DBCI) for high-intensity radiated field (HIRF) electromagnetic radiation is established, which aims to calculate the relationship between the injection excitation voltage source and the radiation field intensity. Additionally, the conditions required for linear extrapolation is clarified. Subsequently, the test method of using DBCI for the HIRF radiated susceptibility (RS) is proposed. Next, the verification of the CST studio and the pass-through load test are performed. All results shows that the test method can avoid the influence of the impedance parameters of the two equipment at both ends, which can be applied to nonlinear terminals for the HIRF RS test.

An integrated approach for electromagnetic compatible commercial aircraft engine cable harnessing

Signal transmission reliability of cable harnesses is essential to commercial aircraft engine performance and flight safety as a commercial aircraft operates in growingly complex electromagnetic (EM) environments. Investigating EM responses of aircraft engine cable harnesses under high-intensity radiated field (HIRF) excitations enables optimization of cable harness configurations, and ensures satisfaction of airworthiness requirements of electromagnetic compatibility (EMC). Comprehending EM responses of aircraft engine cable harnesses also significantly improves robustness of the engine control system against EM disturbances. In alignment with industrial information integration engineering (IIIE), this work develops an integrated EM compatible cable harnessing model consisting sub-models accounting for disciplinary concerns of engine system performance, cable materials, cable structures, EM interferences, electric loadings, control robustness, etc. Then, this work verifies and validates the proposed cable harnessing models by conducting numerical experiments on a given cable harness subject to a number of EM wave interferences. The cable harnessing models and the tandem numerical analysis approaches developed in this work appreciably overcomes deficiencies appeared in relevant previous studies, and substantially support developments of a commercial aircraft engine.

Analysis and Optimization of Nonlinear Diode Grids for Shielding of Enclosures With Apertures

Lumped-element grids provide an attractive option for wave propagation control in electromagnetic compatibility (EMC) engineering. This article investigates the peak shielding effectiveness (SE) of a diode grid used for protection of enclosures with apertures against high-intensity radiation fields (HIRFs). The nonlinearly loaded aperture is investigated with an efficient hybrid field-circuit simulation approach. Numerical experiments show that design aspects, e.g., aperture and enclosure size, grid density, impedance characteristic of lumped loads, play an important role in the field transmission through a diode grid which is nonlinear and time-variant. With a physics-based analysis of the interaction between the grid and the enclosure-backed aperture, nonlinear shielding techniques are identified that allow a control of the peak SE between 0 and 26 dB in novel ways. For the first time, the peak SE curve of a diode grid is demonstrated with four different field intensity dependencies, i.e., intensity low-pass, intensity high-pass, intensity bandpass, and intensity band-stop selectivities from tens V/m to hundreds of V/m. By considering design aspects into a two-step optimization procedure, practical guidelines are provided for the nonlinear shielding implementation.

A Study on the Radiated Susceptibility of Printed Circuit Boards and the Effects of Via Fencing

Because modern electronic systems are likely to be exposed to high intensity radiated fields (HIRF) environments, there is growing interest in understanding how electronic systems are affected by such environments. Backdoor coupling in particular is an area of concern for all electronics, but there is limited understanding about the mechanisms behind backdoor coupling. In this work, we present a study on printed circuit board (PCB) backdoor coupling and the effects of via fencing. Existing work focuses on ideal stackups and indicates that edge radiation is significantly reduced by via fencing. In this study, both full wave electromagnetic modeling and experimental verification are used to investigate both ideal and practical PCB stackups. In the ideal scenario, we find that via fencing substantially reduces coupling, which is consistent with prior work on emissions. In the practical scenario, we incorporate component footprints and traces which naturally introduce openings in the top ground plane. Both simulation and experimental data indicate that via fencing in the practical scenario does not substantially mitigate coupling, suggesting that PCB edge coupling is not the dominant coupling mechanism, even at varying angles of incidence and polarization.

HIRF Broadband Full-Wave Virtual Testing and Experimental Validation

This manuscript reports a broadband full-wave virtual testing with experimental validation of a high intensity radiated fields (HIRF) environment, using a 4 m-long composite aircraft (CFC) prototype of a first stage aircraft fuselage. A numerical methodology based on finite-element method (FEM) and method of moments (MoM) is proposed for efficiently predicting HIRF assay results from 200 MHz to 9 GHz for the first time in literature. Experiments under real conditions and using typical HIRF assays components successfully endorse the proposed approach, with the purpose of significantly saving time and money in the aeronautical industry, as a result of using accurate numerical simulations before the HIRF certification processes.

A quantification control method of electromagnetic environmental effects for complex systems

ABSTRACT Modern aircraft, ship, and other systems have different consequences when faced with the own and external radio frequency, lightning and other electromagnetic environments (EME) radiation, that is called electromagnetic environmental effects (E3). In this paper, a new method of system-level E3 quantitative control is proposed. A two factor E3 impact degree model composed of susceptible receptor importance and consequence severity is established. The selection and calculation method of relevant parameters is given. The application process of this method is illustrated with examples of high intensity radiated fields (HIRF), lightning, electromagnetic interference (EMI) and radiation hazard elements for aircraft. It is proved that this method can quantitatively, clearly and accurately express the impact degree of E3, balance the conflict of multi-index and multi-objective design, and achieve the engineering optimization when solving the whole system, whole element and whole process E3 control problems.

PIN-Diode-Based High-Intensity Radiation Fields (HIRF) Protection of a Printed Dipole Antenna

In this article, a PIN-diode-based high-intensity radiation fields (HIRF) protection method was proposed and the sensitivity to the field intensity of incident wave has been verified by a printed dipole antenna loaded with three pairs of PIN diodes at S-band. To illustrate this method, an equivalent linear circuit was raised to analyze the basic operation principle of the proposed antenna. With a low-power incident wave, the PIN diodes are in off-state and the gain of the proposed antenna remains unaffected; while it drops considerably as the PIN diodes are triggered by HIRF. Furthermore, extensive parametric studies of the structure were analyzed by full-wave simulation to investigate the key factors affecting the performance of HIRF protection and antenna characteristics. Finally, a prototype was fabricated and experiments were implemented to verify the feasibility, which shows a high isolation of 19 dB. To the best of our knowledge, the proposed antenna is the first one to achieve HIRF protection through integrated antenna technology, which features with low cost and compact structure, providing a new perspective.

Coupling Effect Analysis of Airborne Cable under High Intensity Radiation Field Environment

With the improvement of equipment informatization, the importance of electromagnetic compatibility and the adaptability of complex electromagnetic environment has become increasingly prominent, and the influence of high intensity radiation fields (HIRF) on aircraft electronic equipment has become more and more significant, which has seriously threatened flight safety. In order to examine the coupling characteristics of airborne cables under HIRF irradiation, this paper used FEKO electromagnetic simulation software for analyse and study. The influence of different radiation fields, cable types, installed positions and gap structure on the simulation results was analyzed. And coupling patterns of airborne cables in the HIRF environment were obtained. The conclusions obtained in this paper have a definite guiding significance of the research on airborne cable protection for HIRF.

Design and performance of high-temperature furnace and cell holder for in situ spectroscopic, electrochemical, and radiolytic investigations of molten salts.

To facilitate the development of molten salt reactor technologies, a fundamental understanding of the physical and chemical properties of molten salts under the combined conditions of high temperature and intense radiation fields is necessary. Optical spectroscopic (UV-Vis-near IR) and electrochemical techniques are powerful analytical tools to probe molecular structure, speciation, thermodynamics, and kinetics of solution dynamics. Here, we report the design and fabrication of three custom-made apparatus: (i) a multi-port spectroelectrochemical furnace equipped with optical spectroscopic and electrochemical instrumentation, (ii) a high-temperature cell holder for time-resolved optical detection of radiolytic transients in molten salts, and (iii) a miniaturized spectroscopy furnace for the investigation of steady-state electron beam effects on molten salt speciation and composition by optical spectroscopy. Initial results obtained with the spectroelectrochemical furnace (i) and high-temperature cell holder (ii) are reported.