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, Available online ,
doi: 10.11884/HPLPB202537.250014
Abstract:
Strong electromagnetic pulse can form nanosecond rising edge pulse conduction disturbance on the cable in the form of field-transmission line coupling, which poses a great threat to the equipment at the end of the cable. For a certain type of relay protection device, the immunity performance is tested first, and then the high-altitude electromagnetic pulse irradiation test under the field-line coupling path is carried out to obtain the coupling characteristics of the device port. When the common mode current coupled to the signal port reaches 32.45A and above, the device malfunctions. At the same time, the pulse current injection test is carried out. When the pulse current injected into the signal port reaches 36.92A and more, the device malfunctions, further confirming the critical interference threshold of the device port. Through the establishment of the field-line coupling model of the secondary cable in the substation and the signal cable in the protective panel cabinet, the coupling quantity of high-altitude electromagnetic pulse in different scenarios is calculated, and the key points of field-line coupling protection are proposed. The research results can provide reference for the evaluation of anti-interference ability and protection technology of relay protection devices in strong electromagnetic pulse environments.
Strong electromagnetic pulse can form nanosecond rising edge pulse conduction disturbance on the cable in the form of field-transmission line coupling, which poses a great threat to the equipment at the end of the cable. For a certain type of relay protection device, the immunity performance is tested first, and then the high-altitude electromagnetic pulse irradiation test under the field-line coupling path is carried out to obtain the coupling characteristics of the device port. When the common mode current coupled to the signal port reaches 32.45A and above, the device malfunctions. At the same time, the pulse current injection test is carried out. When the pulse current injected into the signal port reaches 36.92A and more, the device malfunctions, further confirming the critical interference threshold of the device port. Through the establishment of the field-line coupling model of the secondary cable in the substation and the signal cable in the protective panel cabinet, the coupling quantity of high-altitude electromagnetic pulse in different scenarios is calculated, and the key points of field-line coupling protection are proposed. The research results can provide reference for the evaluation of anti-interference ability and protection technology of relay protection devices in strong electromagnetic pulse environments.
, Available online ,
doi: 10.11884/HPLPB202537.250116
Abstract:
Improving the wide - temperature operation ability of fiber lasers can effectively enhance the environmental adaptability and operation reliability of fiber lasers under extreme high- and low-temperature conditions, ensure their stable output under complex working conditions, and provide support for technological innovation and industrial upgrading in related fields. Recently, the National University of Defense Technology achieved a near-single-mode all-fiber laser oscillator that can operate stably within the temperature range of −50 to +50 ℃ by directly pumping with fiber-coupled semiconductor lasers. The output power reached 2 kW, which is the highest output power level of fiber lasers operating in a wide temperature range reported publicly so far.
Improving the wide - temperature operation ability of fiber lasers can effectively enhance the environmental adaptability and operation reliability of fiber lasers under extreme high- and low-temperature conditions, ensure their stable output under complex working conditions, and provide support for technological innovation and industrial upgrading in related fields. Recently, the National University of Defense Technology achieved a near-single-mode all-fiber laser oscillator that can operate stably within the temperature range of −50 to +50 ℃ by directly pumping with fiber-coupled semiconductor lasers. The output power reached 2 kW, which is the highest output power level of fiber lasers operating in a wide temperature range reported publicly so far.
, Available online ,
doi: 10.11884/HPLPB202537.250062
Abstract:
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Measurement method for areal density of pulsed X-ray photographic images in metal ejection diagnosis
, Available online ,
doi: 10.11884/HPLPB202537.250025
Abstract:
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
, Available online ,
doi: 10.11884/HPLPB202537.240352
Abstract:
As an advanced 4th generation synchrotron radiation facility, the Shenzhen Innovation Light-source Facility (SILF) storage ring is based on multi-bend achromat (MBA) lattices, which enables an emittance reduction of one to two orders of magnitude pushing beyond the radiation brightness and coherence reached by the 3rd generation storage ring. The multipole magnets of many types for SILF storage ring are under preliminary design, which require high integral field homogeneity. As a result, a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D® python script. The procedure considers also the 3D field effect which makes the optimization more straightforward. In this paper, the design of the quadrupole and sextupole magnets for SILF storage ring is firstly presented, followed by the elaboration of the implemented pole shape optimization method.
As an advanced 4th generation synchrotron radiation facility, the Shenzhen Innovation Light-source Facility (SILF) storage ring is based on multi-bend achromat (MBA) lattices, which enables an emittance reduction of one to two orders of magnitude pushing beyond the radiation brightness and coherence reached by the 3rd generation storage ring. The multipole magnets of many types for SILF storage ring are under preliminary design, which require high integral field homogeneity. As a result, a dedicated pole tip optimization procedure with high efficiency is developed for quadrupole and sextupole magnets with Opera-2D® python script. The procedure considers also the 3D field effect which makes the optimization more straightforward. In this paper, the design of the quadrupole and sextupole magnets for SILF storage ring is firstly presented, followed by the elaboration of the implemented pole shape optimization method.
, Available online ,
doi: 10.11884/HPLPB202537.250016
Abstract:
The Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS) has recently initiated the development of an electrostatic high-voltage ion accelerator. As the core component of this accelerator type, the high-voltage generator is required to meet design specifications including a maximum operational voltage of 4.2 MV, voltage instability below ±0.1%, and ripple coefficient under ±0.1%. To achieve these parameters, simulation-based modeling was first implemented for the overall structural design and optimization of the high-voltage generator, thereby enhancing operational safety and stability.For the critical high-frequency transformer subsystem within the generator, a field-circuit coupling methodology was employed to analyze and optimize both its circuit topology and electrical parameters. Concurrently, thermal dissipation structure modifications were implemented to ensure stable output performance of the transformer. Furthermore, a high-precision voltage stabilization scheme was developed for the generator's control system, proposing optimized control strategies to enhance operational reliability.The research demonstrates that the proposed high-voltage generator design meets the specified technical requirements of the project. This systematic approach integrating electromagnetic design, thermal management optimization, and advanced control methodologies provides valuable insights for developing next-generation high-voltage power systems in accelerator applications.
The Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS) has recently initiated the development of an electrostatic high-voltage ion accelerator. As the core component of this accelerator type, the high-voltage generator is required to meet design specifications including a maximum operational voltage of 4.2 MV, voltage instability below ±0.1%, and ripple coefficient under ±0.1%. To achieve these parameters, simulation-based modeling was first implemented for the overall structural design and optimization of the high-voltage generator, thereby enhancing operational safety and stability.For the critical high-frequency transformer subsystem within the generator, a field-circuit coupling methodology was employed to analyze and optimize both its circuit topology and electrical parameters. Concurrently, thermal dissipation structure modifications were implemented to ensure stable output performance of the transformer. Furthermore, a high-precision voltage stabilization scheme was developed for the generator's control system, proposing optimized control strategies to enhance operational reliability.The research demonstrates that the proposed high-voltage generator design meets the specified technical requirements of the project. This systematic approach integrating electromagnetic design, thermal management optimization, and advanced control methodologies provides valuable insights for developing next-generation high-voltage power systems in accelerator applications.
, Available online ,
doi: 10.11884/HPLPB202537.250021
Abstract:
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
, Available online ,
doi: 10.11884/HPLPB202537.250093
Abstract:
When a MV triggered gas switch (TGS) is triggered by an electric pulse, a good electrical connection between the trigger generator and the TGS is required to ensure the trigger effect. Besides, a protective method is also necessary to avoid the damage to the trigger generator which feeds back from the MV main pulse after the TGS is closed. In this paper, a novel trigger pulse feed and protection method is introduced. The trigger pulse is introduced via a protective resistor, which is mounted between the inner and outer cylindrical electrodes of the pulse transmission line. The MV pulse is attenuated because the voltage is resistively divided by the resistor and trigger cable arrangement. Both the complex breakdown processes of the switch and its insulation issues are experimentally studied. The function and the beneficial effects of the protective resistor, installed together with an additional inductor, are discussed. Finally, the structure and parameters of these two protective components are set to 500 Ω and 2 μH, in which conditions the switch is demonstrated to successfully work at 2.6 MV.
When a MV triggered gas switch (TGS) is triggered by an electric pulse, a good electrical connection between the trigger generator and the TGS is required to ensure the trigger effect. Besides, a protective method is also necessary to avoid the damage to the trigger generator which feeds back from the MV main pulse after the TGS is closed. In this paper, a novel trigger pulse feed and protection method is introduced. The trigger pulse is introduced via a protective resistor, which is mounted between the inner and outer cylindrical electrodes of the pulse transmission line. The MV pulse is attenuated because the voltage is resistively divided by the resistor and trigger cable arrangement. Both the complex breakdown processes of the switch and its insulation issues are experimentally studied. The function and the beneficial effects of the protective resistor, installed together with an additional inductor, are discussed. Finally, the structure and parameters of these two protective components are set to 500 Ω and 2 μH, in which conditions the switch is demonstrated to successfully work at 2.6 MV.
, Available online ,
doi: 10.11884/HPLPB202537.240413
Abstract:
In high-energy laser systems, the performance parameters of large-aperture sampling optics determine the accuracy of beam testing and evaluation, as well as the precision of overall system performance control. This paper focuses on the performance testing requirements of sampling optics with high-reflectivity (HR) on the front surface and anti-reflectivity (AR) on the back surface. Utilizing the cavity ring-down (CRD) based reflectivity uniformity testing of large-aperture sampling optics, the reflectivity distribution, optical loss, and high-resolution scanning imaging of defects of sampling optics are obtained by scanning measuring the incident light form both the reflective film surface and the anti-reflective film surface, respectively. Furthermore, by comparing and analyzing the defect distribution maps, the classification of defects in the reflective film, transmissive film, and substrate of the sampling optics can be achieved. Finally, by establishing a dual channel CRD system, the residual reflectance distribution of anti-reflective film and the types of defects in the transmissive film were obtained. The testing and analysis method proposed in this paper provides a systematic and comprehensive characterization tool for the performance evaluation and defect analysis of sampling optics.
In high-energy laser systems, the performance parameters of large-aperture sampling optics determine the accuracy of beam testing and evaluation, as well as the precision of overall system performance control. This paper focuses on the performance testing requirements of sampling optics with high-reflectivity (HR) on the front surface and anti-reflectivity (AR) on the back surface. Utilizing the cavity ring-down (CRD) based reflectivity uniformity testing of large-aperture sampling optics, the reflectivity distribution, optical loss, and high-resolution scanning imaging of defects of sampling optics are obtained by scanning measuring the incident light form both the reflective film surface and the anti-reflective film surface, respectively. Furthermore, by comparing and analyzing the defect distribution maps, the classification of defects in the reflective film, transmissive film, and substrate of the sampling optics can be achieved. Finally, by establishing a dual channel CRD system, the residual reflectance distribution of anti-reflective film and the types of defects in the transmissive film were obtained. The testing and analysis method proposed in this paper provides a systematic and comprehensive characterization tool for the performance evaluation and defect analysis of sampling optics.
, Available online ,
doi: 10.11884/HPLPB202537.240131
Abstract:
The Peking University (petawatt) laser proton accelerator develops a laser proton radiotherapy system in response to the needs of proton radiation tumor treatment. The common collection section of its horizontal and vertical beam lines mainly consists of three superconducting solenoids (S1-S3). Large stresses are generated in the solenoids during the cooling down and excitation process, in addition, the superconducting solenoids are operated by fast ramping, and the AC loss in the process will have an important impact on the solenoid excitation speed and stable operation. In this paper, the highest field strength and the most complex structure of 7.8T-120 mm solenoid S1 is taken as the research object, and COMSOL Multiphysics software is used to carry out the stress analysis of superconducting solenoids under multi-field conditions, and at the same time, the simulation of the AC loss due to the rapid change of the current is carried out. Subsequently, corresponding experimental studies were carried out to obtain the variation curves of strain with temperature, correlations betweencurrent, magnetic field and strain correspondingly. According to the experiment data, there is a significant positive correlation between the measured values of magnetic field and strain and the change of current, which verifies the rationality of the superconducting solenoid design. It provides experience and reference for the subsequent design and development of similar superconducting magnets.
The Peking University (petawatt) laser proton accelerator develops a laser proton radiotherapy system in response to the needs of proton radiation tumor treatment. The common collection section of its horizontal and vertical beam lines mainly consists of three superconducting solenoids (S1-S3). Large stresses are generated in the solenoids during the cooling down and excitation process, in addition, the superconducting solenoids are operated by fast ramping, and the AC loss in the process will have an important impact on the solenoid excitation speed and stable operation. In this paper, the highest field strength and the most complex structure of 7.8T-120 mm solenoid S1 is taken as the research object, and COMSOL Multiphysics software is used to carry out the stress analysis of superconducting solenoids under multi-field conditions, and at the same time, the simulation of the AC loss due to the rapid change of the current is carried out. Subsequently, corresponding experimental studies were carried out to obtain the variation curves of strain with temperature, correlations betweencurrent, magnetic field and strain correspondingly. According to the experiment data, there is a significant positive correlation between the measured values of magnetic field and strain and the change of current, which verifies the rationality of the superconducting solenoid design. It provides experience and reference for the subsequent design and development of similar superconducting magnets.
, Available online ,
doi: 10.11884/HPLPB202537.240349
Abstract:
In order to improve the performance of waveform digital readout systems based on Analog to Digital Converter (ADC) technology, this paper proposes a multi-channel mismatch error estimation calibration method. Used two domestically produced high-speed ADCs to form a Time-interleaved A/D Conversion (TIADC) system, and the estimation of channel mismatch error (Gain, Time-skew and Offset) can be obtained by integrating particle swarm optimization (PSO) algorithm and gradient descent (GD) method. Meanwhile, using filter equations and Kaiser window truncation to obtain compensation calibration filter coefficient values. This compensation method can be directly implemented on the TIADC hardware platform using Field-Programmable Gate Array(FPGA) as the central processing unit. Moreover this algorithm can achieve online reconstruction of sampling system data. The experimental results show that the algorithm can effectively compensate for channel mismatch errors, and using the behavior level simulation of Vivado development software, the spurious free dynamic range (SFDR) is increased from 32.1 dBFS to 53.1 dBFS, Improve the SFDR to 60.8 dBFS during hardware platform testing. Also this signal reconstruction method is easy to implement in hardware systems and is not limited by the number of channels. has high engineering applicability. This method has high engineering applicability and is simple and easy to implement.
In order to improve the performance of waveform digital readout systems based on Analog to Digital Converter (ADC) technology, this paper proposes a multi-channel mismatch error estimation calibration method. Used two domestically produced high-speed ADCs to form a Time-interleaved A/D Conversion (TIADC) system, and the estimation of channel mismatch error (Gain, Time-skew and Offset) can be obtained by integrating particle swarm optimization (PSO) algorithm and gradient descent (GD) method. Meanwhile, using filter equations and Kaiser window truncation to obtain compensation calibration filter coefficient values. This compensation method can be directly implemented on the TIADC hardware platform using Field-Programmable Gate Array(FPGA) as the central processing unit. Moreover this algorithm can achieve online reconstruction of sampling system data. The experimental results show that the algorithm can effectively compensate for channel mismatch errors, and using the behavior level simulation of Vivado development software, the spurious free dynamic range (SFDR) is increased from 32.1 dBFS to 53.1 dBFS, Improve the SFDR to 60.8 dBFS during hardware platform testing. Also this signal reconstruction method is easy to implement in hardware systems and is not limited by the number of channels. has high engineering applicability. This method has high engineering applicability and is simple and easy to implement.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Display Method:
, Available online ,
doi: 10.11884/HPLPB202537.250032
Abstract:
In this paper, a miniaturized Planar Inverted-F Electromagnetic Protective Antenna is proposed, which achieves adaptive switching between the normal operation mode and the electromagnetic protection mode by loading a U-shaped protective structure on the planar inverted-F antenna. The U-shaped structure is connected to the antenna feed line via PIN diodes. Under normal operation, when the received signal power is below the threshold, the PIN diodes remain in the cutoff state, allowing the antenna to maintain its radiation characteristics without interference from the U-shaped structure. When under high-power microwave attacks, a strong induced electric field is generated across the PIN diodes in the U-shaped structure, causing them to rapidly switch to achieve a low-impedance conduction state. At this point, the U-shaped structure forms a closed loop with the feed line, effectively preventing high-power microwave signals from entering the backend electronic equipment, thereby achieving electromagnetic protection. By optimizing the geometric parameters of the U-shaped structure and the number of loaded diodes, the design maintains its compact size while delivering excellent radiation performance and protection capability. Measurement results show that the antenna achieves a relative bandwidth of 17.2%, with a gain of 2.36 dBi at the center frequency of 1.57 GHz. Simulation results demonstrate a protection level of 16.4 dB in the electromagnetic protection state. The radiator’s electrical dimension is only 0.25λ×0.06λ, realizing a miniaturized design for the electromagnetic protective antenna.
In this paper, a miniaturized Planar Inverted-F Electromagnetic Protective Antenna is proposed, which achieves adaptive switching between the normal operation mode and the electromagnetic protection mode by loading a U-shaped protective structure on the planar inverted-F antenna. The U-shaped structure is connected to the antenna feed line via PIN diodes. Under normal operation, when the received signal power is below the threshold, the PIN diodes remain in the cutoff state, allowing the antenna to maintain its radiation characteristics without interference from the U-shaped structure. When under high-power microwave attacks, a strong induced electric field is generated across the PIN diodes in the U-shaped structure, causing them to rapidly switch to achieve a low-impedance conduction state. At this point, the U-shaped structure forms a closed loop with the feed line, effectively preventing high-power microwave signals from entering the backend electronic equipment, thereby achieving electromagnetic protection. By optimizing the geometric parameters of the U-shaped structure and the number of loaded diodes, the design maintains its compact size while delivering excellent radiation performance and protection capability. Measurement results show that the antenna achieves a relative bandwidth of 17.2%, with a gain of 2.36 dBi at the center frequency of 1.57 GHz. Simulation results demonstrate a protection level of 16.4 dB in the electromagnetic protection state. The radiator’s electrical dimension is only 0.25λ×0.06λ, realizing a miniaturized design for the electromagnetic protective antenna.
, Available online ,
doi: 10.11884/HPLPB202537.240397
Abstract:
The deterministic calculation method based on multi-group cross section has always been an important approach in the design of nuclear reactors. The accuracy of multi-group cross section directly affects the precision of nuclear reactor physics calculations. To generate high-precision cross section data for fast reactors, North China Electric Power University developed the high-precision cross section processing code MGGC2.0. This paper conducts benchmark verification and validation of the code. The infinite homogeneous mixed media UO2, MOX, and U-TRU-Zr fuels are calculated based on the ENDF/B-VII.1 library, and the macroscopic cross sections generated by MGGC2.0 are compared with those produced by MCNP to verify the accuracy of the program in generating multi-group cross sections. The relative deviation of the macroscopic multi-group total cross section from the reference solution of MCNP is generally within 5%. Subsequently, calculations are performed for the Russian fast reactor BFS97-1 experiment, and a homogenization method of the fuel few-group cross section for various fuel arrangements is proposed. The collision probability method in MGGC2.0 is used to calculate the few-group cross section data for the fuel, and the DIF3D program is employed for core calculations. Additionally, this study compares the results obtained using different cross section homogenization methods. The research findings indicate that for BFS97-1, if the cross sections generated directly by critical search are used, the absolute deviation of the keff calculated by DIF3D from that calculated by MCNP is 2.541×10−2. This paper improves the calculation method of axial fuel inhomogeneity, reducing the deviation to below 5.0×10−4. The deviations between the calculated results for BFS97-1, BFS97-2, BFS97-5, and BFS97-6 and the MCNP results are all within3.0×10−3, validating the high accuracy of the code in generating multi-group and few-group cross section, which meets the requirements of engineering design.
The deterministic calculation method based on multi-group cross section has always been an important approach in the design of nuclear reactors. The accuracy of multi-group cross section directly affects the precision of nuclear reactor physics calculations. To generate high-precision cross section data for fast reactors, North China Electric Power University developed the high-precision cross section processing code MGGC2.0. This paper conducts benchmark verification and validation of the code. The infinite homogeneous mixed media UO2, MOX, and U-TRU-Zr fuels are calculated based on the ENDF/B-VII.1 library, and the macroscopic cross sections generated by MGGC2.0 are compared with those produced by MCNP to verify the accuracy of the program in generating multi-group cross sections. The relative deviation of the macroscopic multi-group total cross section from the reference solution of MCNP is generally within 5%. Subsequently, calculations are performed for the Russian fast reactor BFS97-1 experiment, and a homogenization method of the fuel few-group cross section for various fuel arrangements is proposed. The collision probability method in MGGC2.0 is used to calculate the few-group cross section data for the fuel, and the DIF3D program is employed for core calculations. Additionally, this study compares the results obtained using different cross section homogenization methods. The research findings indicate that for BFS97-1, if the cross sections generated directly by critical search are used, the absolute deviation of the keff calculated by DIF3D from that calculated by MCNP is 2.541×10−2. This paper improves the calculation method of axial fuel inhomogeneity, reducing the deviation to below 5.0×10−4. The deviations between the calculated results for BFS97-1, BFS97-2, BFS97-5, and BFS97-6 and the MCNP results are all within3.0×10−3, validating the high accuracy of the code in generating multi-group and few-group cross section, which meets the requirements of engineering design.
, Available online ,
doi: 10.11884/HPLPB202537.240280
Abstract:
To improve the vacuum surface flashover performance of insulators, a kind of composite surface structure consisting of micro grooves and molecule self-assembly membrane was proposed and prepared on the surface of alumina vacuum insulators by laser carving, water cleaning and molecule self-assembly. Meanwhile, insulators with only micro grooves or pure molecule membrane were also prepared. The secondary electron emission yield test showed that both the micro groove structure and molecule self-assembly could reduce the secondary electron emission yield of the alumina insulator. Their combination (the composite surface structure) could further reduce the secondary electron emission yield. Correspondingly, the surface flashover voltage test indicated that surface micro groove construction and molecule self-assembly could both improve the surface flashover voltages and their combination could further improve the flashover voltages. The results demonstrate that molecule membrane and the micro grooves in the composite structure can form dual suppression on the development of the vacuum flashover.
To improve the vacuum surface flashover performance of insulators, a kind of composite surface structure consisting of micro grooves and molecule self-assembly membrane was proposed and prepared on the surface of alumina vacuum insulators by laser carving, water cleaning and molecule self-assembly. Meanwhile, insulators with only micro grooves or pure molecule membrane were also prepared. The secondary electron emission yield test showed that both the micro groove structure and molecule self-assembly could reduce the secondary electron emission yield of the alumina insulator. Their combination (the composite surface structure) could further reduce the secondary electron emission yield. Correspondingly, the surface flashover voltage test indicated that surface micro groove construction and molecule self-assembly could both improve the surface flashover voltages and their combination could further improve the flashover voltages. The results demonstrate that molecule membrane and the micro grooves in the composite structure can form dual suppression on the development of the vacuum flashover.
, Available online ,
doi: 10.11884/HPLPB202537.240401
Abstract:
This paper introduces the working principle, composition and configuration of a miniaturized high-throughput neutron source system. It systematically introduces the piezoelectric pulse power source technology, nuclear reaction design technology, spherical electromagnetic field generation technology, particle proximity acceleration technology, particle polarization and resonance collision technology required for the development of this neutron source system. A complete neutron source physical system was developed and tested for energy spectrum and flux. The expected physical phenomena were observed in the experiments, and the occurrence of nuclear reactions was proved by online and offline neutron measurement methods, and the test results showed that the neutron radiation flux of the new miniature neutron source with a diameter of 2 cm and a length of 4 cm reached the level of 1010 n/(cm2·s), which belongs to strong neutron radiation source.
This paper introduces the working principle, composition and configuration of a miniaturized high-throughput neutron source system. It systematically introduces the piezoelectric pulse power source technology, nuclear reaction design technology, spherical electromagnetic field generation technology, particle proximity acceleration technology, particle polarization and resonance collision technology required for the development of this neutron source system. A complete neutron source physical system was developed and tested for energy spectrum and flux. The expected physical phenomena were observed in the experiments, and the occurrence of nuclear reactions was proved by online and offline neutron measurement methods, and the test results showed that the neutron radiation flux of the new miniature neutron source with a diameter of 2 cm and a length of 4 cm reached the level of 1010 n/(cm2·s), which belongs to strong neutron radiation source.
, Available online ,
doi: 10.11884/HPLPB202537.240400
Abstract:
To effectively solve the problem of strong electromagnetic pulse power required to drive particle reactions, a new pulse power synchronous amplification technology based on hydrogen plasma loading and wave-particle resonance mechanism is studied on the basis of piezoelectric ceramic stack pulse source. The amplification mechanism is as follows: first, the energy of hydrogen molecule bonding orbitals is lower than that of antibonding orbitals, and internal energy will be released during the ionization process to promote the efficient occurrence of the ionization process driven by pulse power; Second, after the ionization of hydrogen atoms, the electromagnetic field and electrons undergo wave-particle resonance, and the electron energy is synchronously converted into electromagnetic field energy. After the amplification of wave-particle resonance, a stronger electromagnetic pulse is obtained, which can form a spherical electromagnetic field when applied to the spiral electrode, and has an extremely high acceleration gradient, which can accelerate a large number of protons produced after efficient ionization of hydrogen atoms. The above theory is effectively proved through experimental tests and simulation analysis, and this research is expected to lay a foundation for a miniaturized and low-cost proton generator driven by strong electromagnetic pulses.
To effectively solve the problem of strong electromagnetic pulse power required to drive particle reactions, a new pulse power synchronous amplification technology based on hydrogen plasma loading and wave-particle resonance mechanism is studied on the basis of piezoelectric ceramic stack pulse source. The amplification mechanism is as follows: first, the energy of hydrogen molecule bonding orbitals is lower than that of antibonding orbitals, and internal energy will be released during the ionization process to promote the efficient occurrence of the ionization process driven by pulse power; Second, after the ionization of hydrogen atoms, the electromagnetic field and electrons undergo wave-particle resonance, and the electron energy is synchronously converted into electromagnetic field energy. After the amplification of wave-particle resonance, a stronger electromagnetic pulse is obtained, which can form a spherical electromagnetic field when applied to the spiral electrode, and has an extremely high acceleration gradient, which can accelerate a large number of protons produced after efficient ionization of hydrogen atoms. The above theory is effectively proved through experimental tests and simulation analysis, and this research is expected to lay a foundation for a miniaturized and low-cost proton generator driven by strong electromagnetic pulses.
, Available online ,
doi: 10.11884/HPLPB202537.250056
Abstract:
To investigate the effects of contact and axial power on the thermodynamic performance of the heat pipe cooled reactor core, a thermal-mechanical coupling program was developed based on the FEniCS platform. The program uses a simplified method to solve 2D and 3D contact pressure, primarily including gap heat transfer, linear elastic mechanics, and multidimensional contact pressure solution models. Taking the MegaPower reactor as the subject, the study first validated the accuracy of the program using ANSYS, and then a thermal-mechanical simulation of the core was performed to analyze temperature and Mises stress fields. The results indicate that when considering contact, the peak temperature of the fuel pin significantly decreases and the Mises stress decreases slightly; the peak temperature of the monolith changes little, but the Mises stress increases markedly. The axial power mainly affects the Mises stress of the fuel pin, while the Mises stress of the monolith is primarily influenced by contact pressure.
To investigate the effects of contact and axial power on the thermodynamic performance of the heat pipe cooled reactor core, a thermal-mechanical coupling program was developed based on the FEniCS platform. The program uses a simplified method to solve 2D and 3D contact pressure, primarily including gap heat transfer, linear elastic mechanics, and multidimensional contact pressure solution models. Taking the MegaPower reactor as the subject, the study first validated the accuracy of the program using ANSYS, and then a thermal-mechanical simulation of the core was performed to analyze temperature and Mises stress fields. The results indicate that when considering contact, the peak temperature of the fuel pin significantly decreases and the Mises stress decreases slightly; the peak temperature of the monolith changes little, but the Mises stress increases markedly. The axial power mainly affects the Mises stress of the fuel pin, while the Mises stress of the monolith is primarily influenced by contact pressure.
, Available online ,
doi: 10.11884/HPLPB202537.240270
Abstract:
Traditional methods for analyzing superconduction radio-frequency (SRF) cavity faults rely on a priori knowledge, featuring high labor and time costs, poor accuracy and low consistency. They are less efficient when dealing with complex devices and large amounts of data. In this paper, a method for classifying SRF cavity faults based on machine learning algorithms is investigated. Using the SRF cavity fault data generated during the operation of BEPCII, the classification of SRF cavity faults is achieved through image information extraction, feature selection and optimization, machine learning algorithm training, and analyzing the accuracy and consistency of the model via K-fold cross validation. The results of the study show that Random Forest, Support Vector Machine and Bagging algorithms have better classification results when dealing with faulty pictures. The accuracy and consistency of supervised learning methods are significantly higher than those of unsupervised learning. The fault classification realized in this research achieves high accuracy and consistency. It enables to quickly and efficiently distinguish the faults occurring on the SRF cavity of BEPCII. It also provides a reference for the diagnosis of SRF cavity faults in other particle accelerators.
Traditional methods for analyzing superconduction radio-frequency (SRF) cavity faults rely on a priori knowledge, featuring high labor and time costs, poor accuracy and low consistency. They are less efficient when dealing with complex devices and large amounts of data. In this paper, a method for classifying SRF cavity faults based on machine learning algorithms is investigated. Using the SRF cavity fault data generated during the operation of BEPCII, the classification of SRF cavity faults is achieved through image information extraction, feature selection and optimization, machine learning algorithm training, and analyzing the accuracy and consistency of the model via K-fold cross validation. The results of the study show that Random Forest, Support Vector Machine and Bagging algorithms have better classification results when dealing with faulty pictures. The accuracy and consistency of supervised learning methods are significantly higher than those of unsupervised learning. The fault classification realized in this research achieves high accuracy and consistency. It enables to quickly and efficiently distinguish the faults occurring on the SRF cavity of BEPCII. It also provides a reference for the diagnosis of SRF cavity faults in other particle accelerators.
, Available online ,
doi: 10.11884/HPLPB202537.240163
Abstract:
The quantitative study of combat effectiveness index is crucial for the informatization construction of the armed forces. To solve the problems of limits of quantitative research, low method accuracy, and weak robustness in the study of combat effectiveness index, and to break through the limitations of dominating complex rules, multivariate mathematical models, and strong coupling of influencing factors in the combat effectiveness index function, inspired by the mathematical analysis methods of rules in fuzzy logic theory, we proposed a local approximation based method for fitting combat effectiveness index function. Combining the powerful self-learning and self-deduction capabilities of neural networks, we constructed a corresponding quantitative calculation model based on radial basis function (RBF). Simulation comparative experiments show that the proposed method has an error rate of about 2% and 6% lower than the current best performing method using global approximation, and exhibits stronger robustness. Our method has strong practicality, can be migrated to other military fields, and has good engineering application prospects.
The quantitative study of combat effectiveness index is crucial for the informatization construction of the armed forces. To solve the problems of limits of quantitative research, low method accuracy, and weak robustness in the study of combat effectiveness index, and to break through the limitations of dominating complex rules, multivariate mathematical models, and strong coupling of influencing factors in the combat effectiveness index function, inspired by the mathematical analysis methods of rules in fuzzy logic theory, we proposed a local approximation based method for fitting combat effectiveness index function. Combining the powerful self-learning and self-deduction capabilities of neural networks, we constructed a corresponding quantitative calculation model based on radial basis function (RBF). Simulation comparative experiments show that the proposed method has an error rate of about 2% and 6% lower than the current best performing method using global approximation, and exhibits stronger robustness. Our method has strong practicality, can be migrated to other military fields, and has good engineering application prospects.
, Available online ,
doi: 10.11884/HPLPB202537.240435
Abstract:
With the in-depth study of particle accelerator physics experiments, the requirements higher for beam quality have gradually increased. To obtain a magnetic field environment with extremely high stability and extremely low noise, a high-precision DC excitation power supply combining switching mode and linear mode was analyzed and designed. The front-end switching power supply provides a stable power source, and the back-end linear power supply is connected in series to control the linear amplification of the current for output. Based on the control loop of power supply current and tube voltage drop, the stability of the output current has been further improved through temperature compensation measures for key components. Through the modular design of the back-end linear power supply, the volume of the power supply has been reduced and the convenience of operation and maintenance has been improved. The measured results show that the long-term current stability for 8 h reaches 1.3×10−6, and the noise is extremely low.
With the in-depth study of particle accelerator physics experiments, the requirements higher for beam quality have gradually increased. To obtain a magnetic field environment with extremely high stability and extremely low noise, a high-precision DC excitation power supply combining switching mode and linear mode was analyzed and designed. The front-end switching power supply provides a stable power source, and the back-end linear power supply is connected in series to control the linear amplification of the current for output. Based on the control loop of power supply current and tube voltage drop, the stability of the output current has been further improved through temperature compensation measures for key components. Through the modular design of the back-end linear power supply, the volume of the power supply has been reduced and the convenience of operation and maintenance has been improved. The measured results show that the long-term current stability for 8 h reaches 1.3×10−6, and the noise is extremely low.
, Available online ,
doi: 10.11884/HPLPB202537.250002
Abstract:
In ultrafast high-power laser systems, achromatic lens groups are typically used to replace standard beam expanders to eliminate spatio-temporal coupling (STC) distortions caused by chromatic aberrations. However, alignment errors in these achromatic lens groups can introduce new STC distortions, reducing far-field power density and compromising the desired correction. This paper quantitatively analyzes the STC distortions induced by three types of alignment errors using a broad-spectrum pulse laser transmission model and a thick lens equivalent phase screen model. The impact of these errors on far-field focusing power density is evaluated, and permissible error ranges for each type are established.
In ultrafast high-power laser systems, achromatic lens groups are typically used to replace standard beam expanders to eliminate spatio-temporal coupling (STC) distortions caused by chromatic aberrations. However, alignment errors in these achromatic lens groups can introduce new STC distortions, reducing far-field power density and compromising the desired correction. This paper quantitatively analyzes the STC distortions induced by three types of alignment errors using a broad-spectrum pulse laser transmission model and a thick lens equivalent phase screen model. The impact of these errors on far-field focusing power density is evaluated, and permissible error ranges for each type are established.
Display Method:
2025, 37: 061001.
doi: 10.11884/HPLPB202537.250096
Abstract:
Mid-infrared lasers hold significant application demands in fields such as medicine, communications, and national defense. In recent years, research on mid-infrared fiber lasers has attracted extensive attention worldwide. This work demonstrates a high-power mid-infrared light source at 4.16 μm utilizing HBr gas-filled anti-resonant hollow-core fiber (AR-HCF). By employing a homemade 2 μm single-frequency fiber amplifier as the pump source and utilizing the intrinsic absorption of gas molecules to achieve population inversion, we have realized over 10 W continuous wave mid-infrared output through backward gas-filling method in large-mode-area (AR-HCF). This optimized configuration simultaneously enhances the optical-to-optical conversion efficiency and effectively suppresses thermal accumulation limitations. At the maximum incident pump power of 63.8 W, the system achieves a maximum continuous output power of 10.37 W with corresponding slope efficiency of approximately 16.8%. The beam quality measurement reveals M2<1.1 at maximum power operation. This research verifies the substantial capability of fiber gas lasers to generate high-power mid-infrared radiation, providing valuable insights for advancing the development and investigation of mid-infrared fiber laser technologies.
Mid-infrared lasers hold significant application demands in fields such as medicine, communications, and national defense. In recent years, research on mid-infrared fiber lasers has attracted extensive attention worldwide. This work demonstrates a high-power mid-infrared light source at 4.16 μm utilizing HBr gas-filled anti-resonant hollow-core fiber (AR-HCF). By employing a homemade 2 μm single-frequency fiber amplifier as the pump source and utilizing the intrinsic absorption of gas molecules to achieve population inversion, we have realized over 10 W continuous wave mid-infrared output through backward gas-filling method in large-mode-area (AR-HCF). This optimized configuration simultaneously enhances the optical-to-optical conversion efficiency and effectively suppresses thermal accumulation limitations. At the maximum incident pump power of 63.8 W, the system achieves a maximum continuous output power of 10.37 W with corresponding slope efficiency of approximately 16.8%. The beam quality measurement reveals M2<1.1 at maximum power operation. This research verifies the substantial capability of fiber gas lasers to generate high-power mid-infrared radiation, providing valuable insights for advancing the development and investigation of mid-infrared fiber laser technologies.
2025, 37: 061002.
doi: 10.11884/HPLPB202537.250004
Abstract:
Laser wireless energy transmission technology has the advantages of high power, long transmission distance, non-contact operation, and simultaneous energy and information transmission, and is expected to become a revolutionary energy transmission method, showing great application potential in consumer electronics, drones, aerospace and other fields. In this paper, the core module of laser wireless energy transmission technology and its development status in the fields of ground, aerospace and underwater at home and abroad are analyzed, and the technical challenges are summarized. Finally, the future development trend of laser wireless energy transmission system is discussed.
Laser wireless energy transmission technology has the advantages of high power, long transmission distance, non-contact operation, and simultaneous energy and information transmission, and is expected to become a revolutionary energy transmission method, showing great application potential in consumer electronics, drones, aerospace and other fields. In this paper, the core module of laser wireless energy transmission technology and its development status in the fields of ground, aerospace and underwater at home and abroad are analyzed, and the technical challenges are summarized. Finally, the future development trend of laser wireless energy transmission system is discussed.
2025, 37: 061003.
doi: 10.11884/HPLPB202537.240433
Abstract:
The output characteristics of a narrow line width optical parametric oscillator with KTP as the nonlinear crystal pumped by a 532 nm wavelength all-solid-state quasi-continuous-wave Nd:YAG laser are studied. A quartz etalon is inserted into the resonant cavity to compress the output laser line width. Through theoretical analysis, the transmission spectra line width of the etalon for the idler wave within the pulsed optical parametric oscillator’s resonant cavity is estimated. Based on the calculation results, the parameters of the etalon for experimental use are designed. By inserting another KTP crystal into the optical parametric oscillator resonant cavity to perform intracavity frequency doubling on the idler, a tunable yellow laser output with a wavelength tuning range of 574.5-577.2 nm and a pm-level line width is achieved. At a repetition rate of 10 kHz and an average pump power of 30 W, the peak wavelength of the frequency doubled yellow light is 575.81 nm, with a corresponding average output power of 155 mW and a pulse width of about 35 ns. The line width at the peak wavelength is only 0.8 pm, and the beam quality factor in the x and y directions is measured respectively as 1.286 and 1.807.
The output characteristics of a narrow line width optical parametric oscillator with KTP as the nonlinear crystal pumped by a 532 nm wavelength all-solid-state quasi-continuous-wave Nd:YAG laser are studied. A quartz etalon is inserted into the resonant cavity to compress the output laser line width. Through theoretical analysis, the transmission spectra line width of the etalon for the idler wave within the pulsed optical parametric oscillator’s resonant cavity is estimated. Based on the calculation results, the parameters of the etalon for experimental use are designed. By inserting another KTP crystal into the optical parametric oscillator resonant cavity to perform intracavity frequency doubling on the idler, a tunable yellow laser output with a wavelength tuning range of 574.5-577.2 nm and a pm-level line width is achieved. At a repetition rate of 10 kHz and an average pump power of 30 W, the peak wavelength of the frequency doubled yellow light is 575.81 nm, with a corresponding average output power of 155 mW and a pulse width of about 35 ns. The line width at the peak wavelength is only 0.8 pm, and the beam quality factor in the x and y directions is measured respectively as 1.286 and 1.807.
2025, 37: 061004.
doi: 10.11884/HPLPB202537.240444
Abstract:
This paper reports on a room-temperature Yb:YAG rod laser with high power and high beam quality. The oscillator utilizes a moderately doped Yb:YAG rod crystal (Yb3+ 2.0 at atomic fraction of %) and employs quasi-continuous-wave end-pumping. At a repetition rate of 100 Hz, it achieved a 22 W linearly polarized laser output, with a slope efficiency of 53.5% and an optical-to-optical efficiency of 47.4%, while maintaining a beam quality of M2 = 1.22. Using acousto-optic Q-switching, the laser produced a 20.8 W pulse output with an energy of 9.9 mJ and a beam quality of M2 = 1.39, demonstrating the laser's capability for high-repetition-rate Q-switched pulse output.
This paper reports on a room-temperature Yb:YAG rod laser with high power and high beam quality. The oscillator utilizes a moderately doped Yb:YAG rod crystal (Yb3+ 2.0 at atomic fraction of %) and employs quasi-continuous-wave end-pumping. At a repetition rate of 100 Hz, it achieved a 22 W linearly polarized laser output, with a slope efficiency of 53.5% and an optical-to-optical efficiency of 47.4%, while maintaining a beam quality of M2 = 1.22. Using acousto-optic Q-switching, the laser produced a 20.8 W pulse output with an energy of 9.9 mJ and a beam quality of M2 = 1.39, demonstrating the laser's capability for high-repetition-rate Q-switched pulse output.
2025, 37: 061005.
doi: 10.11884/HPLPB202537.240407
Abstract:
This paper conducts a detailed study on the influence of second-harmonic parasitic effects in non-collinear ultra-broadband degenerate optical parametric amplification (OPA), which is pumped by frequency-doubled Ti:sapphire lasers. We considered both walk-off compensation and non-walk-off compensation scenarios. The study reveals that, under the non-walk-off compensation method, by appropriately increasing the non-collinear angle between the pump and signal beams, the impact of second-harmonic parasitic effects on the signal’s output spectrum can be effectively reduced while ensuring broad-spectrum amplification of the signal. The evolution of the signal’s output spectrum and output flux is investigated for different pump spectral bandwidths, clarifying the requirements for the pump spectral bandwidth given a specific signal output spectral bandwidth. The research findings provide design guidelines for generating ultra-broadband, high-temporal contrast femtosecond seed based on degenerate OPA.
This paper conducts a detailed study on the influence of second-harmonic parasitic effects in non-collinear ultra-broadband degenerate optical parametric amplification (OPA), which is pumped by frequency-doubled Ti:sapphire lasers. We considered both walk-off compensation and non-walk-off compensation scenarios. The study reveals that, under the non-walk-off compensation method, by appropriately increasing the non-collinear angle between the pump and signal beams, the impact of second-harmonic parasitic effects on the signal’s output spectrum can be effectively reduced while ensuring broad-spectrum amplification of the signal. The evolution of the signal’s output spectrum and output flux is investigated for different pump spectral bandwidths, clarifying the requirements for the pump spectral bandwidth given a specific signal output spectral bandwidth. The research findings provide design guidelines for generating ultra-broadband, high-temporal contrast femtosecond seed based on degenerate OPA.
2025, 37: 061006.
doi: 10.11884/HPLPB202537.240346
Abstract:
Aiming at the problems of low extraction accuracy and weak anti-interference ability of line structure light centroids in turbid water bodies, this study proposes an improved internal advancement algorithm, which aims to enhance the accuracy and robustness of the extraction of line structure light centroids in complex environments. Firstly, the median filter is used to preprocess the image to suppress the noise, and combined with the eight-neighborhood method to quickly locate the starting point of the light stripe; subsequently, the grayscale neighborhood attribute method is introduced to dynamically estimate the pixel width of the current line of the line structured light, and based on this range, the maximum interclass variance method is applied to adaptively determine the binarized threshold value, which effectively reduces the background interference; finally, the grayscale gravity method is used to calculate the initial centroid in the constrained range of pixel widths and use this as the basis to advance upward and downward to search for the center point of the line structured light. Comparison tests are conducted in various turbid water environments and different structured light patterns. The results show that compared with the original internal advancement algorithm, the root mean square error of the improved algorithm is reduced by 13.33%, and the running speed of the algorithm is increased by 69.07% compared with Steger’s algorithm, thus realizes the balance between accuracy and speed.
Aiming at the problems of low extraction accuracy and weak anti-interference ability of line structure light centroids in turbid water bodies, this study proposes an improved internal advancement algorithm, which aims to enhance the accuracy and robustness of the extraction of line structure light centroids in complex environments. Firstly, the median filter is used to preprocess the image to suppress the noise, and combined with the eight-neighborhood method to quickly locate the starting point of the light stripe; subsequently, the grayscale neighborhood attribute method is introduced to dynamically estimate the pixel width of the current line of the line structured light, and based on this range, the maximum interclass variance method is applied to adaptively determine the binarized threshold value, which effectively reduces the background interference; finally, the grayscale gravity method is used to calculate the initial centroid in the constrained range of pixel widths and use this as the basis to advance upward and downward to search for the center point of the line structured light. Comparison tests are conducted in various turbid water environments and different structured light patterns. The results show that compared with the original internal advancement algorithm, the root mean square error of the improved algorithm is reduced by 13.33%, and the running speed of the algorithm is increased by 69.07% compared with Steger’s algorithm, thus realizes the balance between accuracy and speed.
2025, 37: 061007.
doi: 10.11884/HPLPB202537.240392
Abstract:
The influence of grating height on the diffraction efficiency of SU-8 micron gratings was studied.The diffraction efficiency of gratings with heights of 6-8 μm, 12-16 μm, and 6-30 μm was simulated and analyzed using rigorous coupled wave theory. The simulation results show that when the grating height is 6 μm, the 0th order diffraction efficiency is the lowest and the 1st order diffraction efficiency is the highest; At 12 μm, the 0th order diffraction efficiency is the highest and the 1st order diffraction efficiency is the lowest. When the grating height continuously changes from 6-30 μm, the diffraction efficiency varies periodically. SU-8 thin films with different thicknesses were prepared, and 40 μm periodic gratings with different gate heights were fabricated using picosecond laser etching technology. The measurement results show that when the grating height of the 40 μm period grating is 6.83 μm, the −1st order diffraction efficiency is 28.4%, and the 0th order diffraction efficiency is about 14.7%; When the grating height is 13.45 μm , the 0th order diffraction efficiency is 31.46% and the 1st order diffraction efficiency is 12.35%. The magnitude of the 0th and 1st order diffraction efficiencies varies with the grating height period. The theoretical simulation and experimental exploration can provide important references for the preparation of SU-8 micron gratings and the improvement of first-order diffraction efficiency.
The influence of grating height on the diffraction efficiency of SU-8 micron gratings was studied.The diffraction efficiency of gratings with heights of 6-8 μm, 12-16 μm, and 6-30 μm was simulated and analyzed using rigorous coupled wave theory. The simulation results show that when the grating height is 6 μm, the 0th order diffraction efficiency is the lowest and the 1st order diffraction efficiency is the highest; At 12 μm, the 0th order diffraction efficiency is the highest and the 1st order diffraction efficiency is the lowest. When the grating height continuously changes from 6-30 μm, the diffraction efficiency varies periodically. SU-8 thin films with different thicknesses were prepared, and 40 μm periodic gratings with different gate heights were fabricated using picosecond laser etching technology. The measurement results show that when the grating height of the 40 μm period grating is 6.83 μm, the −1st order diffraction efficiency is 28.4%, and the 0th order diffraction efficiency is about 14.7%; When the grating height is 13.45 μm , the 0th order diffraction efficiency is 31.46% and the 1st order diffraction efficiency is 12.35%. The magnitude of the 0th and 1st order diffraction efficiencies varies with the grating height period. The theoretical simulation and experimental exploration can provide important references for the preparation of SU-8 micron gratings and the improvement of first-order diffraction efficiency.
2025, 37: 063001.
doi: 10.11884/HPLPB202537.240411
Abstract:
To address the wideband and beam scanning requirements of high-power microwave (HPM) systems, this paper proposes an X-band varactor-based high-power wideband beam-scanning reflectarray antenna. The antenna employs a linearly polarized horn feed and a sandwich-structured embedded patch element, where the nested dual-resonance structure integrated with varactors simultaneously extends the phase tuning range (360°) and operational bandwidth. By eliminating abrupt structural discontinuities and adopting a sandwich dielectric configuration, the design effectively suppresses triple-junction formation, achieving a power capacity of 5 MW in 0.1 MPa SF6 environment. Varactor capacitance adjustment enables a 12% relative tuning bandwidth within 8.55−9.65 GHz. Simulations of an 11×11 rectangular grid reflectarray demonstrate a maximum gain of 25.12 dBi with 54.39% aperture efficiency for a 242 mm aperture and full-band 0°−20° beam scanning capability. Compared with existing technologies, this design exhibits superior tuning bandwidth (12%) and power capacity (5 MW), providing an effective solution for wideband beam control in HPM systems.
To address the wideband and beam scanning requirements of high-power microwave (HPM) systems, this paper proposes an X-band varactor-based high-power wideband beam-scanning reflectarray antenna. The antenna employs a linearly polarized horn feed and a sandwich-structured embedded patch element, where the nested dual-resonance structure integrated with varactors simultaneously extends the phase tuning range (360°) and operational bandwidth. By eliminating abrupt structural discontinuities and adopting a sandwich dielectric configuration, the design effectively suppresses triple-junction formation, achieving a power capacity of 5 MW in 0.1 MPa SF6 environment. Varactor capacitance adjustment enables a 12% relative tuning bandwidth within 8.55−9.65 GHz. Simulations of an 11×11 rectangular grid reflectarray demonstrate a maximum gain of 25.12 dBi with 54.39% aperture efficiency for a 242 mm aperture and full-band 0°−20° beam scanning capability. Compared with existing technologies, this design exhibits superior tuning bandwidth (12%) and power capacity (5 MW), providing an effective solution for wideband beam control in HPM systems.
2025, 37: 063002.
doi: 10.11884/HPLPB202537.250028
Abstract:
The signal compensation method based on Wiener filtering has been demonstrated to have excellent compensation performance towards the signal distortion induced by the long-distance transmission in coaxial cable. However, factors affect the compensation performance of this method had not been investigated and analyzed, thus we carried out a systematic study on the effect of the parameters and the means of this modified method. The results show the main factors are the signal-to-noise ratio (SNR), the sampling frequency interval Δf in S21 parameter measurement, and the power spectrum estimation method. When the SNR is less than 25 dB, the compensation performance continuously improves as the SNR increases. Once the SNR exceeds 25 dB, the relative error (δ) between the compensated signal and input signal nearly keeps unchanged. The compensation performance keeps unchanged when Δf is small, and it slowly deteriorates as Δf exceeds a certain value. It is proved that among the traditional power spectrum estimation methods, the Burg method can obtain the best compensation performance. This study can provide a beneficial reference for the application of the signal compensation method based on Wiener filtering.
The signal compensation method based on Wiener filtering has been demonstrated to have excellent compensation performance towards the signal distortion induced by the long-distance transmission in coaxial cable. However, factors affect the compensation performance of this method had not been investigated and analyzed, thus we carried out a systematic study on the effect of the parameters and the means of this modified method. The results show the main factors are the signal-to-noise ratio (SNR), the sampling frequency interval Δf in S21 parameter measurement, and the power spectrum estimation method. When the SNR is less than 25 dB, the compensation performance continuously improves as the SNR increases. Once the SNR exceeds 25 dB, the relative error (δ) between the compensated signal and input signal nearly keeps unchanged. The compensation performance keeps unchanged when Δf is small, and it slowly deteriorates as Δf exceeds a certain value. It is proved that among the traditional power spectrum estimation methods, the Burg method can obtain the best compensation performance. This study can provide a beneficial reference for the application of the signal compensation method based on Wiener filtering.
2025, 37: 063003.
doi: 10.11884/HPLPB202537.240386
Abstract:
During the integration of High Power Microwave (HPM) systems, the docking condition of the microwave source and the transmission-emission subsystem affects the HPM system performance directly. Poor docking conditions may cause radio frequency breakdown at the connection surface, which will result in the reduction of the entire system’s output power. Therefore, diagnosing the docking state of the system is of great engineering significance. For this reason, a non-contact high-power microwave transmission technology is investigated in this paper, and an injection power measurement method is proposed for a Ku-band GW-level HPM system using a conical horn as the feed source. Based on simulation designs, key subassembly of the technology was developed. In addition, the small signal test and power handling capacity assessment of the subassembly were carried out. The experimental outcomes demonstrated that the reflection coefficient was consistently below −26 dB, the coupling coefficient was (−0.31±0.07) dB within the frequency band of (15±0.15) GHz, and the power handling capacity exceeded 900 MW. The experimental and simulation results show that the proposed measurement technology not only has the characteristics of stable coupling coefficient and low test errors, but also can effectively measure the microwave power injected by HPM source through the feed-horn and diagnose the docking state of the HPM system.
During the integration of High Power Microwave (HPM) systems, the docking condition of the microwave source and the transmission-emission subsystem affects the HPM system performance directly. Poor docking conditions may cause radio frequency breakdown at the connection surface, which will result in the reduction of the entire system’s output power. Therefore, diagnosing the docking state of the system is of great engineering significance. For this reason, a non-contact high-power microwave transmission technology is investigated in this paper, and an injection power measurement method is proposed for a Ku-band GW-level HPM system using a conical horn as the feed source. Based on simulation designs, key subassembly of the technology was developed. In addition, the small signal test and power handling capacity assessment of the subassembly were carried out. The experimental outcomes demonstrated that the reflection coefficient was consistently below −26 dB, the coupling coefficient was (−0.31±0.07) dB within the frequency band of (15±0.15) GHz, and the power handling capacity exceeded 900 MW. The experimental and simulation results show that the proposed measurement technology not only has the characteristics of stable coupling coefficient and low test errors, but also can effectively measure the microwave power injected by HPM source through the feed-horn and diagnose the docking state of the HPM system.
2025, 37: 064001.
doi: 10.11884/HPLPB202537.240240
Abstract:
In response to the timing requirements for the commissioning and offline operation of many pre-research equipments at the China Spallation Neutron Source Phase II (CSNS-II), a timing system has been designed and developed independently based on “high-precision timing generator + low-jitter fiber optical transmission link”, which provides accurate triggers for the pre-research equipments in accordance with the physical design requirements. The hardware mainly consists of with cost-effective master boards and terminal boards, which realize strict synchronization and low-jitter transmission. Meanwhile, the master board has the ability to expand the number of output channels by using multimode optical fiber to realize the cascade connection of the hardware boards through high-speed serial transmission links; the upper software adopts adopts the method of “Serial Server + PC soft IOC” to realise the data interaction mechanism between the master board and Experimental Physics and Industrial Control System (EPICS), which can accurately configure the frequency, delay, pulse width and other parameters remotely. The synchronous timing system has been successfully used in the commissioning and operation of key pre-research equipments such as the radio frequency ion source of the CSNS-II, which has been operated stably and reliably for a long period of time. In addition, compared with commercial products, the timing system has the advantages of flexible design, strong anti-interference capability, and high versatility, which can provide a practical technical reference for the design and realisation of timing system for particle accelerator equipment at home and abroad.
In response to the timing requirements for the commissioning and offline operation of many pre-research equipments at the China Spallation Neutron Source Phase II (CSNS-II), a timing system has been designed and developed independently based on “high-precision timing generator + low-jitter fiber optical transmission link”, which provides accurate triggers for the pre-research equipments in accordance with the physical design requirements. The hardware mainly consists of with cost-effective master boards and terminal boards, which realize strict synchronization and low-jitter transmission. Meanwhile, the master board has the ability to expand the number of output channels by using multimode optical fiber to realize the cascade connection of the hardware boards through high-speed serial transmission links; the upper software adopts adopts the method of “Serial Server + PC soft IOC” to realise the data interaction mechanism between the master board and Experimental Physics and Industrial Control System (EPICS), which can accurately configure the frequency, delay, pulse width and other parameters remotely. The synchronous timing system has been successfully used in the commissioning and operation of key pre-research equipments such as the radio frequency ion source of the CSNS-II, which has been operated stably and reliably for a long period of time. In addition, compared with commercial products, the timing system has the advantages of flexible design, strong anti-interference capability, and high versatility, which can provide a practical technical reference for the design and realisation of timing system for particle accelerator equipment at home and abroad.
2025, 37: 064002.
doi: 10.11884/HPLPB202537.240257
Abstract:
To facilitate online replacement and maintenance of solid-state power sources in particle accelerators, a cavity power combiner with online decoupling capability is required. While cavity combiners offer high power capacity, adjustable input coupling has not been achieved online. Therefore, we designed a 650 MHz eight-in-one cavity power combiner with a rotatable decoupling system. By integrating non-contact open-circuit slits at the RF input port and separating the coupling loop from the cavity, we enabled online rotation adjustment of the magnetic coupling loop. This adjustment allows real-time tuning of input coupling according to the operational status of solid-state power sources, facilitating hot-swapping and efficiency optimization. Simulation results demonstrate high synthesis efficiency and minimal power loss, with excellent amplitude consistency between input and output ports (deviations within 0.25 dB). The ability to adjust coupling online enhances RF isolation at input ports, enabling seamless hot-swappable replacement of power amplifier modules and significantly improving maintainability and flexibility.
To facilitate online replacement and maintenance of solid-state power sources in particle accelerators, a cavity power combiner with online decoupling capability is required. While cavity combiners offer high power capacity, adjustable input coupling has not been achieved online. Therefore, we designed a 650 MHz eight-in-one cavity power combiner with a rotatable decoupling system. By integrating non-contact open-circuit slits at the RF input port and separating the coupling loop from the cavity, we enabled online rotation adjustment of the magnetic coupling loop. This adjustment allows real-time tuning of input coupling according to the operational status of solid-state power sources, facilitating hot-swapping and efficiency optimization. Simulation results demonstrate high synthesis efficiency and minimal power loss, with excellent amplitude consistency between input and output ports (deviations within 0.25 dB). The ability to adjust coupling online enhances RF isolation at input ports, enabling seamless hot-swappable replacement of power amplifier modules and significantly improving maintainability and flexibility.
2025, 37: 064003.
doi: 10.11884/HPLPB202537.240271
Abstract:
The ionization profile monitor (IPM) can provide critical beam distribution information required for real-time debugging and stable operation of high-current proton accelerators. The IPM system of the China Spallation Neutron Source (CSNS) Linac adopts a compact structural design. It collects data in ion mode and performs one-dimensional transverse beam distribution measurement through an optical imaging system. However, the honeycomb mesh structure at the electrode plate apertures blocks some ions or electrons from entering the microchannel plate, causing imaging shadows and introducing beam distribution distortion. Offline numerical algorithms must be used for correction. In this paper, partial differential equation (PDE) restoration and machine learning algorithms are used to correct the imaging shadows and beam distribution distortion caused by the honeycomb mesh of the IPM in the CSNS linac. The unsupervised machine learning method DIP (Deep Image Prior) was employed, and the corrected beam size deviates from the theoretical expectation by less than 10%, while maintaining a good signal-to-noise ratio.
The ionization profile monitor (IPM) can provide critical beam distribution information required for real-time debugging and stable operation of high-current proton accelerators. The IPM system of the China Spallation Neutron Source (CSNS) Linac adopts a compact structural design. It collects data in ion mode and performs one-dimensional transverse beam distribution measurement through an optical imaging system. However, the honeycomb mesh structure at the electrode plate apertures blocks some ions or electrons from entering the microchannel plate, causing imaging shadows and introducing beam distribution distortion. Offline numerical algorithms must be used for correction. In this paper, partial differential equation (PDE) restoration and machine learning algorithms are used to correct the imaging shadows and beam distribution distortion caused by the honeycomb mesh of the IPM in the CSNS linac. The unsupervised machine learning method DIP (Deep Image Prior) was employed, and the corrected beam size deviates from the theoretical expectation by less than 10%, while maintaining a good signal-to-noise ratio.
2025, 37: 064004.
doi: 10.11884/HPLPB202537.240299
Abstract:
For a facility using multi-group magnetic cores, its operation stability will be affected by the different working points of the multi-group magnetic cores being reset in parallel. A direct current reset system of the multi-pulse induction cells is developed instead of the original parallel pulsed reset system for a multi-pulse high power Linear Induction Accelerator (LIA) at burst mode. Resetting multi-group magnetic cores one by one is realized by a separate relay switch for every induction cell and constant current sources with periodical output using the direct current reset system, and the problem of inconsistency in working points caused by parallel pulsed reset is effectively resolved. During engineering implementation, the system operates with two sets of constant current sources and eight switch control boxes to reset 94 groups of induction cell magnetic cores, significantly reducing system complexity and maintenance costs. Practical validation demonstrates that the improved accelerator exhibits enhanced multi-pulse stability, with beam centroid position jitter reduced from 1.3 mm to less than 1 mm. This paper describes the physical design of the direct current reset unit, introduces the layout of the whole reset system which includes the main units, and presents the improvement effect.
For a facility using multi-group magnetic cores, its operation stability will be affected by the different working points of the multi-group magnetic cores being reset in parallel. A direct current reset system of the multi-pulse induction cells is developed instead of the original parallel pulsed reset system for a multi-pulse high power Linear Induction Accelerator (LIA) at burst mode. Resetting multi-group magnetic cores one by one is realized by a separate relay switch for every induction cell and constant current sources with periodical output using the direct current reset system, and the problem of inconsistency in working points caused by parallel pulsed reset is effectively resolved. During engineering implementation, the system operates with two sets of constant current sources and eight switch control boxes to reset 94 groups of induction cell magnetic cores, significantly reducing system complexity and maintenance costs. Practical validation demonstrates that the improved accelerator exhibits enhanced multi-pulse stability, with beam centroid position jitter reduced from 1.3 mm to less than 1 mm. This paper describes the physical design of the direct current reset unit, introduces the layout of the whole reset system which includes the main units, and presents the improvement effect.
2025, 37: 065001.
doi: 10.11884/HPLPB202537.240383
Abstract:
The insulating property of water medium affects the operation state of pulse power device, and air bubbles in water are the main factor causing breakdown of water medium. To remove air bubbles and dissolved gases in the water medium, we analyzed the causes of air bubbles in the water medium. For the removal of body-phase air bubbles and surface adsorption air bubbles in the water medium, we compared the methods of removing air bubbles using vortex separators and reverse osmosis membranes, and we have carried out experimental research to study the performance of these two methods. The results show that the vortex separator’s low cyclonic strength leads to low separation (which can remove the gas bubbles and dissolved gases in the water) efficiency, and the reverse osmosis membrane degassing makes the surface adsorbed bubbles re-dissolve by reducing the solubility of the gas in the water, and the separation efficiency is high. This study is of great significance for the stable operation of the pulsed power device.
The insulating property of water medium affects the operation state of pulse power device, and air bubbles in water are the main factor causing breakdown of water medium. To remove air bubbles and dissolved gases in the water medium, we analyzed the causes of air bubbles in the water medium. For the removal of body-phase air bubbles and surface adsorption air bubbles in the water medium, we compared the methods of removing air bubbles using vortex separators and reverse osmosis membranes, and we have carried out experimental research to study the performance of these two methods. The results show that the vortex separator’s low cyclonic strength leads to low separation (which can remove the gas bubbles and dissolved gases in the water) efficiency, and the reverse osmosis membrane degassing makes the surface adsorbed bubbles re-dissolve by reducing the solubility of the gas in the water, and the separation efficiency is high. This study is of great significance for the stable operation of the pulsed power device.
2025, 37: 065002.
doi: 10.11884/HPLPB202537.240412
Abstract:
With the continuous development of photoconductive microwave technology towards high-frequency, high-power, long-life, and high-efficiency directions, lateral photoconductive devices have the potential to achieve high photoelectric gain and high main frequency response due to intrinsic light triggering and low parasitic capacitance. We investigated the photocurrent response of intrinsic light back-illuminated lateral silicon carbide (SiC) photoconductive switches. Based on semiconductor numerical simulation, the output photocurrent of the device under intrinsic light triggering with different substrate thicknesses and different light powers was compared for front and back illumination. The internal current and electric field distribution of the device were analyzed and compared. Finally, experimental tests were conducted on the front and back triggering of a 50 μm lateral SiC photoconductive switch. The experimental results show that under a 40 kW peak light power, the on-resistance of the back-triggered device is reduced by 40% compared to the front-triggered device, confirming the high photoelectric conversion efficiency of the back-illuminated device, and the internal electric field and current of the back-triggered device are more uniform, which is more conducive to improving the device’s high-power capacity. The results provide simulation and experimental references for the intrinsic triggering of planar photoconductive switches.
With the continuous development of photoconductive microwave technology towards high-frequency, high-power, long-life, and high-efficiency directions, lateral photoconductive devices have the potential to achieve high photoelectric gain and high main frequency response due to intrinsic light triggering and low parasitic capacitance. We investigated the photocurrent response of intrinsic light back-illuminated lateral silicon carbide (SiC) photoconductive switches. Based on semiconductor numerical simulation, the output photocurrent of the device under intrinsic light triggering with different substrate thicknesses and different light powers was compared for front and back illumination. The internal current and electric field distribution of the device were analyzed and compared. Finally, experimental tests were conducted on the front and back triggering of a 50 μm lateral SiC photoconductive switch. The experimental results show that under a 40 kW peak light power, the on-resistance of the back-triggered device is reduced by 40% compared to the front-triggered device, confirming the high photoelectric conversion efficiency of the back-illuminated device, and the internal electric field and current of the back-triggered device are more uniform, which is more conducive to improving the device’s high-power capacity. The results provide simulation and experimental references for the intrinsic triggering of planar photoconductive switches.
2025, 37: 065003.
doi: 10.11884/HPLPB202537.240186
Abstract:
When the photoconductive switch operates continuously under the working conditions of long pulse width and high repetition frequency, due to the existence of a certain conduction resistance, the thermal deposition phenomenon inside the switch is relatively serious, which is likely to cause thermal damage and thermal breakdown of the photoconductive switch, seriously affecting its service life. Therefore, it is necessary to effectively dissipate heat from the high-power photoconductive switch. The conventional cooling circulation system uses the method of pumping out by a circulation pump to cool the object. There are problems such as very high or low pressure of the cooling medium during the circulation process, resulting in uneven cooling of the object, which is extremely likely to cause damage to the object. In addition, the impeller of the circulation pump will generate bubbles during the circulation process, reducing the insulation strength of the photoconductive switch and leading to flashover breakdown along the surface. To address these issues, we have developed a cooling system that eliminates bubbles based on the negative pressure suction mechanism and achieves precise temperature control through a dual-loop system. This system has achieved good heat dissipation for the photoconductive switch. Under the conditions of a working voltage of 11 kV, an output current of 560 A, a pulse width of 55 ns, and a repetition frequency of 1 kHz, the service life of the photoconductive switch has reached 106 times, which is significantly increased.
When the photoconductive switch operates continuously under the working conditions of long pulse width and high repetition frequency, due to the existence of a certain conduction resistance, the thermal deposition phenomenon inside the switch is relatively serious, which is likely to cause thermal damage and thermal breakdown of the photoconductive switch, seriously affecting its service life. Therefore, it is necessary to effectively dissipate heat from the high-power photoconductive switch. The conventional cooling circulation system uses the method of pumping out by a circulation pump to cool the object. There are problems such as very high or low pressure of the cooling medium during the circulation process, resulting in uneven cooling of the object, which is extremely likely to cause damage to the object. In addition, the impeller of the circulation pump will generate bubbles during the circulation process, reducing the insulation strength of the photoconductive switch and leading to flashover breakdown along the surface. To address these issues, we have developed a cooling system that eliminates bubbles based on the negative pressure suction mechanism and achieves precise temperature control through a dual-loop system. This system has achieved good heat dissipation for the photoconductive switch. Under the conditions of a working voltage of 11 kV, an output current of 560 A, a pulse width of 55 ns, and a repetition frequency of 1 kHz, the service life of the photoconductive switch has reached 106 times, which is significantly increased.
2025, 37: 065004.
doi: 10.11884/HPLPB202537.240426
Abstract:
This study focuses on the performance of vertical photoconductive semiconductor switch (PCSS) based on Fe: β-Ga2O3 under high voltage. The results show that deep levels in Fe: β-Ga2O3 can provide carriers of non-intrinsic excitation. The device did not exhibit breakdown tendencies when subjected to a 20 kV input voltage with single-shot laser triggering. After more than5000 trigger cycles at 15 kV by a 10 Hz laser, the switch eventually failed. Nevertheless, pulse performance remained stable throughout the effective data collection period, preliminarily demonstrating the potential of Ga2O3 PCSS for applications in extreme conditions such as high power and high frequency. Failure analysis indicates that a wide bandgap is not the sole determinant of high breakdown voltage. In addition to employing precise doping techniques to introduce specific defects and modify material properties, further improvements in existing material growth methods and device packaging structures can also contribute to enhancing the output and lifetime of PCSS.
This study focuses on the performance of vertical photoconductive semiconductor switch (PCSS) based on Fe: β-Ga2O3 under high voltage. The results show that deep levels in Fe: β-Ga2O3 can provide carriers of non-intrinsic excitation. The device did not exhibit breakdown tendencies when subjected to a 20 kV input voltage with single-shot laser triggering. After more than
2025, 37: 066001.
doi: 10.11884/HPLPB202537.250011
Abstract:
The geoelectric fields induced by late-time high altitude electromagnetic pulse (HEMP E3) and geomagnetic storms lead to low frequency geomagnetically induced currents in the transmission grids, and the resulting half-cycle saturation of a large number of transformers could potentially threaten the power system voltage stability. However, in the existing study on HEMP E3 effect evaluation, it typically assumes a uniform or 1D layered earth structure, without adequately considering the influence of lateral variations in earth conductivity on the induced geoelectric fields. Thus, it is difficult to rigorously assess the electromagnetic security of power systems under complex geological conditions such as coasts. This paper establishes a 3D computational model for HEMP E3 geoelectric fields based on finite element method, then studies the influence of complex earth conductivity structure on the spatiotemporal distribution of HEMP E3 geoelectric fields, and finally evaluates the power system voltage stability via electromagnetic transient simulation method. The results uncover substantial changes in the amplitude and duration of HEMP E3 geoelectric fields near the conductivity interface, which may lead to significant deviation in the voltage stability results of the power system. The method developed in this paper provides an important basis for the HEMP effect evaluation and protection of infrastructure located in complex geological areas.
The geoelectric fields induced by late-time high altitude electromagnetic pulse (HEMP E3) and geomagnetic storms lead to low frequency geomagnetically induced currents in the transmission grids, and the resulting half-cycle saturation of a large number of transformers could potentially threaten the power system voltage stability. However, in the existing study on HEMP E3 effect evaluation, it typically assumes a uniform or 1D layered earth structure, without adequately considering the influence of lateral variations in earth conductivity on the induced geoelectric fields. Thus, it is difficult to rigorously assess the electromagnetic security of power systems under complex geological conditions such as coasts. This paper establishes a 3D computational model for HEMP E3 geoelectric fields based on finite element method, then studies the influence of complex earth conductivity structure on the spatiotemporal distribution of HEMP E3 geoelectric fields, and finally evaluates the power system voltage stability via electromagnetic transient simulation method. The results uncover substantial changes in the amplitude and duration of HEMP E3 geoelectric fields near the conductivity interface, which may lead to significant deviation in the voltage stability results of the power system. The method developed in this paper provides an important basis for the HEMP effect evaluation and protection of infrastructure located in complex geological areas.
2025, 37: 066002.
doi: 10.11884/HPLPB202537.240408
Abstract:
In a surface nuclear leakage scenario, radiation neutrons undergo multiple scatterings with atomic nuclei in the material, rapidly reducing their energy to the thermal neutron range (a few eV). The activation of thermal neutrons significantly impacts the nuclear reaction process. In solid and liquid materials, nuclei typically exist in bound states, differing from free nuclei in gaseous form regarding their interaction with matter. To accurately assess nuclear radiation effects, we investigated the impact of bound-nucleus effects on thermal neutron activation. Using the Monte Carlo method for particle transport simulation, we developed an air-ground interface model based on surface nuclear radiation scenarios. We modeled neutron beam interactions with soil, seawater, and concrete, focusing on thermal neutron activation reactions. By incorporating bound-nucleus effects through adjusted reaction cross-sections, we calculated and compared changes in secondary gamma flux before and after considering these effects. The results show that accounting for bound-nucleus effects enhances thermal neutron activation in solid and liquid media, thereby increasing surface secondary gamma field intensity. Due to factors such as elemental composition and particle shielding, the maximum increases in secondary gamma flux were 18%, 8%, and 11% for the three media, with varying patterns of flux increase over detection distances.
In a surface nuclear leakage scenario, radiation neutrons undergo multiple scatterings with atomic nuclei in the material, rapidly reducing their energy to the thermal neutron range (a few eV). The activation of thermal neutrons significantly impacts the nuclear reaction process. In solid and liquid materials, nuclei typically exist in bound states, differing from free nuclei in gaseous form regarding their interaction with matter. To accurately assess nuclear radiation effects, we investigated the impact of bound-nucleus effects on thermal neutron activation. Using the Monte Carlo method for particle transport simulation, we developed an air-ground interface model based on surface nuclear radiation scenarios. We modeled neutron beam interactions with soil, seawater, and concrete, focusing on thermal neutron activation reactions. By incorporating bound-nucleus effects through adjusted reaction cross-sections, we calculated and compared changes in secondary gamma flux before and after considering these effects. The results show that accounting for bound-nucleus effects enhances thermal neutron activation in solid and liquid media, thereby increasing surface secondary gamma field intensity. Due to factors such as elemental composition and particle shielding, the maximum increases in secondary gamma flux were 18%, 8%, and 11% for the three media, with varying patterns of flux increase over detection distances.
2025, 37: 069001.
doi: 10.11884/HPLPB202537.250001
Abstract:
Terahertz waves, spanning the millimeter and submillimeter wavelength ranges between the microwave and far-infrared regions (approximately 3 mm to 30 μm), represent a critical spectral range in astrophysical and cosmological research. Of the photons detectable since the beginning of the universe, approximately 98% fall within the terahertz and far-infrared bands. A significant proportion of these photons originate from the cosmic microwave background radiation, while others arise from excited molecules that exhibit bright spectral emissions in the terahertz range. As a result, terahertz-based astronomical observation techniques are becoming increasingly essential for investigating the universe’s fundamental properties. Through the observation of interstellar atoms, molecules, and dust, terahertz astronomy provides valuable insights into the internal conditions of the interstellar medium and offers a unique observational window into the formation and evolution of stars, planets, galaxies, and the universe itself. In recent years, many large astronomical telescopes have begun incorporating terahertz detectors based on microwave kinetic inductance detector (MKID), positioning MKID as a pivotal technology in the field of terahertz astronomical detection. This paper outlines the fundamental principles of MKID, reviews recent advancements in the application of MKIDs to terahertz detection, and discusses future developments in this promising area of research.
Terahertz waves, spanning the millimeter and submillimeter wavelength ranges between the microwave and far-infrared regions (approximately 3 mm to 30 μm), represent a critical spectral range in astrophysical and cosmological research. Of the photons detectable since the beginning of the universe, approximately 98% fall within the terahertz and far-infrared bands. A significant proportion of these photons originate from the cosmic microwave background radiation, while others arise from excited molecules that exhibit bright spectral emissions in the terahertz range. As a result, terahertz-based astronomical observation techniques are becoming increasingly essential for investigating the universe’s fundamental properties. Through the observation of interstellar atoms, molecules, and dust, terahertz astronomy provides valuable insights into the internal conditions of the interstellar medium and offers a unique observational window into the formation and evolution of stars, planets, galaxies, and the universe itself. In recent years, many large astronomical telescopes have begun incorporating terahertz detectors based on microwave kinetic inductance detector (MKID), positioning MKID as a pivotal technology in the field of terahertz astronomical detection. This paper outlines the fundamental principles of MKID, reviews recent advancements in the application of MKIDs to terahertz detection, and discusses future developments in this promising area of research.
2025, 37: 069002.
doi: 10.11884/HPLPB202537.240360
Abstract:
A simple and effective improved A* algorithm is proposed to solve the problem of robot path planning in the integrated installation of large-scale laser devices. Compared with the traditional A* algorithm, the algorithm has been improved in three steps. Firstly, the walking direction is limited, which avoids the phenomenon of crossing obstacles occurred in the traditional A* algorithm; Secondly, the heuristic function is optimized as a weighted Manhattan distance function, which accelerates the expansion of nodes in the x direction or y direction, and reduces the surge of traversal nodes caused by limiting the walking direction. Thirdly, the turning penalty term is introduced to reduce the number of turns in the path planning process, and improve the search efficiency and quality. The performance of the three-step improved A* algorithm is verified in different size raster maps, and compared with the traditional A* algorithm. Experimental results show that in simple maps, the number of nodes traversed by the three-step improved A* algorithm is slightly higher than that of the traditional A* algorithm, and the number of turns is equivalent to that of the traditional A* algorithm, but the obstacle avoidance performance is obviously better than that of the traditional A* algorithm, which is more conducive to the safe walking of robots. In complex maps, considering the priority relationship of traversal nodes, turn times and path length, the parameters of the three-step improved A* algorithm can be adjusted to obtain the optimal path planning result.
A simple and effective improved A* algorithm is proposed to solve the problem of robot path planning in the integrated installation of large-scale laser devices. Compared with the traditional A* algorithm, the algorithm has been improved in three steps. Firstly, the walking direction is limited, which avoids the phenomenon of crossing obstacles occurred in the traditional A* algorithm; Secondly, the heuristic function is optimized as a weighted Manhattan distance function, which accelerates the expansion of nodes in the x direction or y direction, and reduces the surge of traversal nodes caused by limiting the walking direction. Thirdly, the turning penalty term is introduced to reduce the number of turns in the path planning process, and improve the search efficiency and quality. The performance of the three-step improved A* algorithm is verified in different size raster maps, and compared with the traditional A* algorithm. Experimental results show that in simple maps, the number of nodes traversed by the three-step improved A* algorithm is slightly higher than that of the traditional A* algorithm, and the number of turns is equivalent to that of the traditional A* algorithm, but the obstacle avoidance performance is obviously better than that of the traditional A* algorithm, which is more conducive to the safe walking of robots. In complex maps, considering the priority relationship of traversal nodes, turn times and path length, the parameters of the three-step improved A* algorithm can be adjusted to obtain the optimal path planning result.
2025, 37: 069003.
doi: 10.11884/HPLPB202537.240229
Abstract:
To optimize the performance of the pulsed xenon lamp sterilization device, the influence of spectral range and specifications of lamps on the sterilization effect is studied based on a self-developed high-energy microsecond pulse power supply and xenon lamps with different specifications. The results show that in the UV-visible spectrum of a xenon lamp with an arc length of 50 mm and a pressure of 50 kPa, the UV accounts for 38.5% and the UVC accounts for 17.6%. Increasing the arc length and decreasing the pressure can both increase the spectral intensity, and the latter can also increase the ratio of UV. The xenon lamp with an arc length of 100 mm and a pressure of 50 kPa can basically inactivate all Escherichia coli in 3 s with a discharge energy of 20 J. The sterilization rate is positively correlated with arc length and discharge energy of the lamp, negatively correlated with pressure. All bands of xenon lamp radiation have sterilization effects, with UV accounting for 87.7% in log value and the wavelength band less than 280 nm accounting for 64.6%. The AFM images show that pulsed xenon lamp changed the morphology and mechanical properties of Escherichia coli, hence the bacteria shrank, their surface roughness, elasticity, and adhesion increased.
To optimize the performance of the pulsed xenon lamp sterilization device, the influence of spectral range and specifications of lamps on the sterilization effect is studied based on a self-developed high-energy microsecond pulse power supply and xenon lamps with different specifications. The results show that in the UV-visible spectrum of a xenon lamp with an arc length of 50 mm and a pressure of 50 kPa, the UV accounts for 38.5% and the UVC accounts for 17.6%. Increasing the arc length and decreasing the pressure can both increase the spectral intensity, and the latter can also increase the ratio of UV. The xenon lamp with an arc length of 100 mm and a pressure of 50 kPa can basically inactivate all Escherichia coli in 3 s with a discharge energy of 20 J. The sterilization rate is positively correlated with arc length and discharge energy of the lamp, negatively correlated with pressure. All bands of xenon lamp radiation have sterilization effects, with UV accounting for 87.7% in log value and the wavelength band less than 280 nm accounting for 64.6%. The AFM images show that pulsed xenon lamp changed the morphology and mechanical properties of Escherichia coli, hence the bacteria shrank, their surface roughness, elasticity, and adhesion increased.
