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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/HPLPB202537.250062
Abstract:
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Aiming at the electromagnetic pulse protection requirements of RF front-end in complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in L-band is designed. This circuit takes PIN diode as the core device, adopts a multi-level PIN diode cascade protection structure, connects each stage through microstrip transmission lines and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, return loss is less than 11.93 dB, and standing wave ratio is less than 1.68. It has good signal transmission performance; Under the injection of 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast edge pulse. Combined with the low loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
Measurement method for areal density of pulsed X-ray photographic images in metal ejection diagnosis
, Available online , doi: 10.11884/HPLPB202537.250025
Abstract:
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulse X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images, obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed areal density measurement method can accurately obtain the areal density information of metal ejection experimental X-ray images.
, Available online , doi: 10.11884/HPLPB202537.250021
Abstract:
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
Common power equipment in the factory and maintenance needs lightning impact voltage testing to detect the level of insulation equipment. This paper proposes a miniaturized impulse voltage generator different from the traditional gas ball gap. It adopts a modular multi-stage structure, uses the Marx topology as the main circuit, and uses MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, which the host computer can flexibly adjust. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output; when 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
, 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/HPLPB202537.250116
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/HPLPB202537.240413
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/HPLPB202537.240352
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/HPLPB202537.240131
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.
