Email alert
RSS2019 Vol. 31, No. 6
Recommend Articles
Display Method:
2019,
31: 060000.
2019,
31: 060101.
doi: 10.11884/HPLPB201931.190139
Abstract:
Aiming for electron cyclotron heating application in plasma fusion system, a 28 GHz 50 kW gyrotron has been developed and fabricated. The gyrotron employs a triode magnetron injection gun, a conventional cylindrical cavity working under TE02 mode, a built-in quasi-optical mode converter with conversion efficiency of about 95%. In the experiment, Gaussian beams of 54.8 kW for 1 s pulse and 45.6 kW for 30 s continuous wave at 28.08 GHz were achieved. The corresponding total efficiency is 57%.
Aiming for electron cyclotron heating application in plasma fusion system, a 28 GHz 50 kW gyrotron has been developed and fabricated. The gyrotron employs a triode magnetron injection gun, a conventional cylindrical cavity working under TE02 mode, a built-in quasi-optical mode converter with conversion efficiency of about 95%. In the experiment, Gaussian beams of 54.8 kW for 1 s pulse and 45.6 kW for 30 s continuous wave at 28.08 GHz were achieved. The corresponding total efficiency is 57%.
2019,
31: 061001.
doi: 10.11884/HPLPB201931.180298
Abstract:
We use the swing ion-beam etching method to fabricate short wave infrared convex blazed gratings. This method solves the consistency problem of blaze angles by swing etching through the meridian direction of the gratings. A geometric model is built to analyze the influence of swinging speed and beam slit width on groove evolution. Convex gratings with a 45.5 gr/mm groove density, 67 mm aperture, 156.88 mm radius of curvature and 2.2° blaze angle have been fabricated and measured. Experimental results validate that high-efficiency convex gratings of small blaze angle and high groove consistency can be produced by swing etching to satisfy the requirements for high spectral resolution and miniaturization of imaging spectrometers.
We use the swing ion-beam etching method to fabricate short wave infrared convex blazed gratings. This method solves the consistency problem of blaze angles by swing etching through the meridian direction of the gratings. A geometric model is built to analyze the influence of swinging speed and beam slit width on groove evolution. Convex gratings with a 45.5 gr/mm groove density, 67 mm aperture, 156.88 mm radius of curvature and 2.2° blaze angle have been fabricated and measured. Experimental results validate that high-efficiency convex gratings of small blaze angle and high groove consistency can be produced by swing etching to satisfy the requirements for high spectral resolution and miniaturization of imaging spectrometers.
2019,
31: 062001.
doi: 10.11884/HPLPB201931.180339
Abstract:
This paper studies settles systematically the physical process of the laser indirect-driven ignition target implosion. The theoretical methods and one-dimensional hydro-dynamics simulations are used to give key scaling laws in capsule implosion. Based on these scaling laws, the volcanic islands of capsule mass-radius parameter space are obtained under the given conditions of hohlraum radiation temperature, in-flight adiabat, shaping velocity and ablator material. The variations in performance parameters with radiation temperature, in-flight adiabat, etc. are investigated. When the hohlraum radiation temperature increaseds, the stability of the capsule implosion will be better. And the capsule radius needs to be decreased under the condition that the mass is constant. When the in-flight adiabat increases, the energy gain decreases slightly and the stability becomes better. However the reduction in the one-dimensional ignition threshold factor results in a narrowing of the area of the volcanic island. When the shaping speed increases, the area of the volcanic island becomes slightly larger, and the stability change is not significant. The capsule radius needs to be increased under the condition that the capsule mass is constant, which causes larger aspect ratio. When the shell ablator material is changed to improve the mass ablation rate and the ablation pressure, the energy gain is larger and the stability is better. The capsule radius needs to be decreased under the condition that the capsule mass is constant.
This paper studies settles systematically the physical process of the laser indirect-driven ignition target implosion. The theoretical methods and one-dimensional hydro-dynamics simulations are used to give key scaling laws in capsule implosion. Based on these scaling laws, the volcanic islands of capsule mass-radius parameter space are obtained under the given conditions of hohlraum radiation temperature, in-flight adiabat, shaping velocity and ablator material. The variations in performance parameters with radiation temperature, in-flight adiabat, etc. are investigated. When the hohlraum radiation temperature increaseds, the stability of the capsule implosion will be better. And the capsule radius needs to be decreased under the condition that the mass is constant. When the in-flight adiabat increases, the energy gain decreases slightly and the stability becomes better. However the reduction in the one-dimensional ignition threshold factor results in a narrowing of the area of the volcanic island. When the shaping speed increases, the area of the volcanic island becomes slightly larger, and the stability change is not significant. The capsule radius needs to be increased under the condition that the capsule mass is constant, which causes larger aspect ratio. When the shell ablator material is changed to improve the mass ablation rate and the ablation pressure, the energy gain is larger and the stability is better. The capsule radius needs to be decreased under the condition that the capsule mass is constant.
2019,
31: 062002.
doi: 10.11884/HPLPB201931.180373
Abstract:
With the development of ultra-precision machining technology, complex fluid is increasingly utilized. The analysis of ultra-precision machining fluid field is characterized by complex geometry, diverse constitutive equation and free boundary flow, which results in unsatisfactory analysis if adopting traditional numerical method. Based on general characteristic of fluid field, a robust and widely adaptable fluid analysis method is proposed in this paper by applying D. G. Christopherson's super-relaxation iterative method for nonnegative second order partial differential systems to ultra-precision machining fluid field analysis. Besides, taking magnetorheological finishing as an example, the numerical calculation of pressure field is conducted for the polishing area and it is revealed that the calculated pressure distribution has reasonable morphology and it extends from positive x axis to negative x axis, which agrees with the experiment results by Zheng Ligong et al. Moreover, the in-situ experimental measurement of normal pressure by Kistler sensor is conducted for immersion depth ranging over 0.1 to 0.3 mm, it is demonstrated that the relative errors of calculations against experimental results are all less than 20%, indicating that the proposed method is valid and accurate.
With the development of ultra-precision machining technology, complex fluid is increasingly utilized. The analysis of ultra-precision machining fluid field is characterized by complex geometry, diverse constitutive equation and free boundary flow, which results in unsatisfactory analysis if adopting traditional numerical method. Based on general characteristic of fluid field, a robust and widely adaptable fluid analysis method is proposed in this paper by applying D. G. Christopherson's super-relaxation iterative method for nonnegative second order partial differential systems to ultra-precision machining fluid field analysis. Besides, taking magnetorheological finishing as an example, the numerical calculation of pressure field is conducted for the polishing area and it is revealed that the calculated pressure distribution has reasonable morphology and it extends from positive x axis to negative x axis, which agrees with the experiment results by Zheng Ligong et al. Moreover, the in-situ experimental measurement of normal pressure by Kistler sensor is conducted for immersion depth ranging over 0.1 to 0.3 mm, it is demonstrated that the relative errors of calculations against experimental results are all less than 20%, indicating that the proposed method is valid and accurate.
2019,
31: 063001.
doi: 10.11884/HPLPB201931.190068
Abstract:
Voltage tunable metamaterial of short cross type array based on liquid crystal (LC) is proposed to achieve phase compensation at U-band frequencies. Simulation results show, by increasing bias voltage from 0 to 14 V, the metamaterial presents 250° phase compensation at 52 GHz. Moreover, the resonant frequency is continuously and reversibly shifted from 53.6 GHz to 49.9 GHz. By adjusting the permittivity of the LC excitation region of the metamaterial to change the resonance characteristic of the array unit, phase compensation is achieved, which provides a new method for the design of the planar reflect array antenna.
Voltage tunable metamaterial of short cross type array based on liquid crystal (LC) is proposed to achieve phase compensation at U-band frequencies. Simulation results show, by increasing bias voltage from 0 to 14 V, the metamaterial presents 250° phase compensation at 52 GHz. Moreover, the resonant frequency is continuously and reversibly shifted from 53.6 GHz to 49.9 GHz. By adjusting the permittivity of the LC excitation region of the metamaterial to change the resonance characteristic of the array unit, phase compensation is achieved, which provides a new method for the design of the planar reflect array antenna.
2019,
31: 063002.
doi: 10.11884/HPLPB201931.190024
Abstract:
The high-power microwave (HPM) short pulse radar uses high power microwave as transmitting signal, which doesn't work well with the model of the conventional radar transmitting signal. This paper analyses the characteristics of HPM signal, and finds that it has irregular envelope and jittery phase. Therefore, we fit its envelope by Gauss multi-peak model and its phase by polynomial model. We obtain its pulse modulation model, and verify the method of reconstruction with small residual by Matlab. Our study is significant to the simulation of this new kind of radar.
The high-power microwave (HPM) short pulse radar uses high power microwave as transmitting signal, which doesn't work well with the model of the conventional radar transmitting signal. This paper analyses the characteristics of HPM signal, and finds that it has irregular envelope and jittery phase. Therefore, we fit its envelope by Gauss multi-peak model and its phase by polynomial model. We obtain its pulse modulation model, and verify the method of reconstruction with small residual by Matlab. Our study is significant to the simulation of this new kind of radar.
2019,
31: 063201.
doi: 10.11884/HPLPB201931.180372
Abstract:
The performance of array antenna with a large number of elements is affected by the emerging failure elements, and the performance restoration can be achieved by the evolution of the remaining normal elements through evolutionary reconfiguration. The array antennas' evolutionary reconfiguration is analyzed. The fitness function types in self-repair process are analyzed. The evaluation process of different fitness functions is designed. Through the self-repair simulation experiment of a Chebyshev linear array, the self-repair results of array antennas with different fitness functions are analyzed. The analysis result shows that the fitness function based on performance parameters and the combination of pattern matching and performance parameters have better performance. The analysis result provides a reference for the fitness function selection in array antenna self-repair.
The performance of array antenna with a large number of elements is affected by the emerging failure elements, and the performance restoration can be achieved by the evolution of the remaining normal elements through evolutionary reconfiguration. The array antennas' evolutionary reconfiguration is analyzed. The fitness function types in self-repair process are analyzed. The evaluation process of different fitness functions is designed. Through the self-repair simulation experiment of a Chebyshev linear array, the self-repair results of array antennas with different fitness functions are analyzed. The analysis result shows that the fitness function based on performance parameters and the combination of pattern matching and performance parameters have better performance. The analysis result provides a reference for the fitness function selection in array antenna self-repair.
2019,
31: 063202.
doi: 10.11884/HPLPB201931.180328
Abstract:
For the complex system of electronic information equipment system of systems(SoS), the former modeling method based on reductionism cannot behave the complexity of electronic equipment SoS, so the object-process methodology(OPM) is adopted to solve this problem. According to the basic difficulty of conventional systemic and systematic modeling method on the methodology, the modeling requirement is analyzed for the complexity of electronic information equipment SoS. The modeling method is studied for electronic information equipment SoS based on OPM, and the modeling is taken for electronic information equipment SoS on the uniform frame. In the modeling, the equipment SoS consists of the framework, function and behavior with different domains and specialties. The electronic information equipment SoS structure and combat process are modeled primarily by OPM, and these two static and dynamic models are combined to form the global concept model. A typical example of air-defense SoS is illustrated, and the SoS conceptual model exploiting method is demonstrated by OPM, and the result shows the validity of the modeling method.
For the complex system of electronic information equipment system of systems(SoS), the former modeling method based on reductionism cannot behave the complexity of electronic equipment SoS, so the object-process methodology(OPM) is adopted to solve this problem. According to the basic difficulty of conventional systemic and systematic modeling method on the methodology, the modeling requirement is analyzed for the complexity of electronic information equipment SoS. The modeling method is studied for electronic information equipment SoS based on OPM, and the modeling is taken for electronic information equipment SoS on the uniform frame. In the modeling, the equipment SoS consists of the framework, function and behavior with different domains and specialties. The electronic information equipment SoS structure and combat process are modeled primarily by OPM, and these two static and dynamic models are combined to form the global concept model. A typical example of air-defense SoS is illustrated, and the SoS conceptual model exploiting method is demonstrated by OPM, and the result shows the validity of the modeling method.
2019,
31: 063203.
doi: 10.11884/HPLPB201931.190035
Abstract:
The display is an important part of human-computer interaction. When the human body electrostatic discharge occurs on the surface of the display, it may lead to hardware and software faults. In order to study the experimental characteristics of air electrostatic discharge on display, the air electrostatic discharge current and the displacement current through the display screen were measured by a self-made device. It is found that the peak value of discharge current increases with the increase of approaching velocity, and the rising time decreases with the increase of approaching velocity. In the voltage range of ±10-±12 kV, the rise time increases and the peak current decreases under the influence of arc length. With the increase of the distance between the measurement point and the discharge point, the peak value of the displacement current waveform decreases and the rising time increases. The peak value of the positive polarity discharge is larger and the diffusion range is wider, while the rising time of the negative polarity discharge is more obvious. The charge density can be calculated from the displacement current waveform and its distribution. The charge density decreases with the distance of discharge position increasing. Although the peak value of negative polarity discharge current is lower than that of positive polarity, the charge density is higher.This indicates that the negative polarity discharge has a higher damage risk.
The display is an important part of human-computer interaction. When the human body electrostatic discharge occurs on the surface of the display, it may lead to hardware and software faults. In order to study the experimental characteristics of air electrostatic discharge on display, the air electrostatic discharge current and the displacement current through the display screen were measured by a self-made device. It is found that the peak value of discharge current increases with the increase of approaching velocity, and the rising time decreases with the increase of approaching velocity. In the voltage range of ±10-±12 kV, the rise time increases and the peak current decreases under the influence of arc length. With the increase of the distance between the measurement point and the discharge point, the peak value of the displacement current waveform decreases and the rising time increases. The peak value of the positive polarity discharge is larger and the diffusion range is wider, while the rising time of the negative polarity discharge is more obvious. The charge density can be calculated from the displacement current waveform and its distribution. The charge density decreases with the distance of discharge position increasing. Although the peak value of negative polarity discharge current is lower than that of positive polarity, the charge density is higher.This indicates that the negative polarity discharge has a higher damage risk.
2019,
31: 063204.
doi: 10.11884/HPLPB201931.190126
Abstract:
The complex electromagnetic environment is a great threat to radio fuze, taking continuous wave Doppler radio fuze for example, a method based on frequency entropy by analyzing the frequency domain characteristic fuze detection output signal is proposed. The KFCM algorithm is used for classifying and recognizing target signal and jamming signal. As the end trajectory characteristic of fuze determines the fact that the received jamming signal power increase rapidly and the signal-to-noise ratio gets worse. Thus, combined with the KFCM incremental update model, the classification model is adjusted in real time according to signal-to-noise ratio to get a better effect. The result of experiment indicate that the KFCM algorithm with incremental update has good effect on the classification and recognition of target signal at different signal-to-noise ratio, and it can effectively improve the ability of anti-jamming of radio fuze.
The complex electromagnetic environment is a great threat to radio fuze, taking continuous wave Doppler radio fuze for example, a method based on frequency entropy by analyzing the frequency domain characteristic fuze detection output signal is proposed. The KFCM algorithm is used for classifying and recognizing target signal and jamming signal. As the end trajectory characteristic of fuze determines the fact that the received jamming signal power increase rapidly and the signal-to-noise ratio gets worse. Thus, combined with the KFCM incremental update model, the classification model is adjusted in real time according to signal-to-noise ratio to get a better effect. The result of experiment indicate that the KFCM algorithm with incremental update has good effect on the classification and recognition of target signal at different signal-to-noise ratio, and it can effectively improve the ability of anti-jamming of radio fuze.
2019,
31: 063205.
doi: 10.11884/HPLPB201931.190057
Abstract:
In recent years, the research and development of gas discharge theory, material science and electrical measurement technology, which are related to the field of electrostatic discharge (ESD), have gradually moved from the experimental stage to the practical stage. At the same time, people have gradually found that the harm caused by ESD to human beings is very alarming. It can not only affect the normal life of human beings, but also limit the improvement of automation production level. Based on traditional electrostatic discharge the simulator with single equipment and limited function, can not meet the all-round and multi-purpose experimental requirements of electrostatic discharge. To solve this problem, a complete experimental simulator including electrode simulation, azimuth conversion and circuit transmission was designed and implemented. The device is mainly composed of six parts: base, support frame, metal ball, discharge needle, insulating ring and azimuth dial. It can meet the experimental requirements of electromagnetic field in different polarization directions, and also can judge and identify the basic polarization direction of electromagnetic field in different altitudes and positions. The system is innovative and advanced, and provides powerful hardware support for the study of electromagnetic induced electrostatic discharge experiments.
In recent years, the research and development of gas discharge theory, material science and electrical measurement technology, which are related to the field of electrostatic discharge (ESD), have gradually moved from the experimental stage to the practical stage. At the same time, people have gradually found that the harm caused by ESD to human beings is very alarming. It can not only affect the normal life of human beings, but also limit the improvement of automation production level. Based on traditional electrostatic discharge the simulator with single equipment and limited function, can not meet the all-round and multi-purpose experimental requirements of electrostatic discharge. To solve this problem, a complete experimental simulator including electrode simulation, azimuth conversion and circuit transmission was designed and implemented. The device is mainly composed of six parts: base, support frame, metal ball, discharge needle, insulating ring and azimuth dial. It can meet the experimental requirements of electromagnetic field in different polarization directions, and also can judge and identify the basic polarization direction of electromagnetic field in different altitudes and positions. The system is innovative and advanced, and provides powerful hardware support for the study of electromagnetic induced electrostatic discharge experiments.
2019,
31: 063206.
doi: 10.11884/HPLPB201931.190053
Abstract:
The uniformity of high-intensity electromagnetic radiation field is mainly realized by multiple tests at a single point presently, which will inevitably lead to measurement errors due to the time-varying characteristics of the radiation signal itself. Moreover, the method of multiple tests at a single point greatly increases the test time and lowers the test efficiency. To solve these problems, a device realizing multi-points test was designed. The test area can be adjusted automatically. The simulation results show that the device can meet the 9-point uniformity test of radiation field in the range of 500 mm×500 mm-1500 mm×1500 mm. In the 1000 mm×1000 mm test area, the experimental verification was carried out for the two frequency points of 1.35 GHz and 2.88 GHz. The experiment shows that the designed test device can meet the 9-point automatic test requirement of high-intensity radiation field uniformity, which greatly improves the test efficiency and automation.
The uniformity of high-intensity electromagnetic radiation field is mainly realized by multiple tests at a single point presently, which will inevitably lead to measurement errors due to the time-varying characteristics of the radiation signal itself. Moreover, the method of multiple tests at a single point greatly increases the test time and lowers the test efficiency. To solve these problems, a device realizing multi-points test was designed. The test area can be adjusted automatically. The simulation results show that the device can meet the 9-point uniformity test of radiation field in the range of 500 mm×500 mm-1500 mm×1500 mm. In the 1000 mm×1000 mm test area, the experimental verification was carried out for the two frequency points of 1.35 GHz and 2.88 GHz. The experiment shows that the designed test device can meet the 9-point automatic test requirement of high-intensity radiation field uniformity, which greatly improves the test efficiency and automation.
2019,
31: 065001.
doi: 10.11884/HPLPB201931.180300
Abstract:
Magneto-hydrodynamic (MHD) code has been widely used in the field of high current pulse technology, astrophysics and so on. Especially in recent years, with the rapid development of high pulse technology and magnetically driven experiments such as Z-pinch, magnetically driven flyer plate and magnetically driven quasi-isentropic/shock compression, experimental researchers and designers pay more and more attention to the correctness and reliability of MHD code. The verification and validation of the two dimensional magnetically driven simulation code MDSC2 is an important means to evaluate its correctness and reliability. In this paper, the MDSC2 code is verified by ways of comparison with artificial solutions, mesh convergence analysis and comparison with mature codes, and it is also validated by experiments, using magnetically driven one-sided flyer plate, magnetically driven two-sided flyer plates and magnetically driven solid liner. The numerical simulation shows that, the MDSC2 code not only correctly represents the MHD equations, but also can correctly simulate the magnetically driven experiments.
Magneto-hydrodynamic (MHD) code has been widely used in the field of high current pulse technology, astrophysics and so on. Especially in recent years, with the rapid development of high pulse technology and magnetically driven experiments such as Z-pinch, magnetically driven flyer plate and magnetically driven quasi-isentropic/shock compression, experimental researchers and designers pay more and more attention to the correctness and reliability of MHD code. The verification and validation of the two dimensional magnetically driven simulation code MDSC2 is an important means to evaluate its correctness and reliability. In this paper, the MDSC2 code is verified by ways of comparison with artificial solutions, mesh convergence analysis and comparison with mature codes, and it is also validated by experiments, using magnetically driven one-sided flyer plate, magnetically driven two-sided flyer plates and magnetically driven solid liner. The numerical simulation shows that, the MDSC2 code not only correctly represents the MHD equations, but also can correctly simulate the magnetically driven experiments.
2019,
31: 065002.
doi: 10.11884/HPLPB201931.180270
Abstract:
To realize the research of high voltage plasma discharge, we have developed a pulse power system that meets the load requirements. The power system uses a pulse-capacitor power topology scheme combined with theoretical calculations to provide a key guiding solution for actual power supply development. In order to better select the device parameters, the simulation model is built using the PSpice software, and the device parameters satisfying the system requirements are obtained through the response waveform analysis. In addition, the power system has also developed a control system that meets plasma discharge requirements. The control system adopts the communication mode for serial communication, Labview to build the upper computer interface and the FPGA to complete the logic system configuration of the lower computer, and the system is simple and efficient.
To realize the research of high voltage plasma discharge, we have developed a pulse power system that meets the load requirements. The power system uses a pulse-capacitor power topology scheme combined with theoretical calculations to provide a key guiding solution for actual power supply development. In order to better select the device parameters, the simulation model is built using the PSpice software, and the device parameters satisfying the system requirements are obtained through the response waveform analysis. In addition, the power system has also developed a control system that meets plasma discharge requirements. The control system adopts the communication mode for serial communication, Labview to build the upper computer interface and the FPGA to complete the logic system configuration of the lower computer, and the system is simple and efficient.
2019,
31: 065101.
doi: 10.11884/HPLPB201931.190020
Abstract:
According to low-emittance, short-pulse and low-charge-in-single-bunch properties of laser-driven proton beam, we study the feasibility of cavity beam position monitor (BPM) to measure the transverse position of proton beam generated by laser accelerator. In view of the large transverse distribution and divergence angle of proton beam, we derive the output signal when it goes through the cavity BPM, and the result shows that the output signal is identical to that generated by the beam passing through the symmetry center of the transverse distribution and at a certain angle of inclination. Based on the above principle, we use CST software to design and simulate cavity BPM, and determine the scheme of rectangular cavity with coupling waveguide. We discuss the applicability of this scheme for laser-accelerated beam and the resolution of different laser-driven proton beam parameters, and estimate the resolution of PW laser acceleration system.
According to low-emittance, short-pulse and low-charge-in-single-bunch properties of laser-driven proton beam, we study the feasibility of cavity beam position monitor (BPM) to measure the transverse position of proton beam generated by laser accelerator. In view of the large transverse distribution and divergence angle of proton beam, we derive the output signal when it goes through the cavity BPM, and the result shows that the output signal is identical to that generated by the beam passing through the symmetry center of the transverse distribution and at a certain angle of inclination. Based on the above principle, we use CST software to design and simulate cavity BPM, and determine the scheme of rectangular cavity with coupling waveguide. We discuss the applicability of this scheme for laser-accelerated beam and the resolution of different laser-driven proton beam parameters, and estimate the resolution of PW laser acceleration system.
2019,
31: 065102.
doi: 10.11884/HPLPB201931.180291
Abstract:
The structure of thick pinhole with double cones is studied and designed for the spot size measurement of the high-energy intense-current linear induction accelerator (LIA) light source. The theoretical model for numerical calculations is built up according to the parameters of the light source and the practical layout of the experimental measurement. The imaging process of photons penetrating through the thick pinhole structure is simulated, and the impact of the spot size, distribution and off axis on the source spot measurement is analyzed. Calculated results show that the spatial resolution on the source plane reaches 5 lp/mm.
The structure of thick pinhole with double cones is studied and designed for the spot size measurement of the high-energy intense-current linear induction accelerator (LIA) light source. The theoretical model for numerical calculations is built up according to the parameters of the light source and the practical layout of the experimental measurement. The imaging process of photons penetrating through the thick pinhole structure is simulated, and the impact of the spot size, distribution and off axis on the source spot measurement is analyzed. Calculated results show that the spatial resolution on the source plane reaches 5 lp/mm.
2019,
31: 065103.
doi: 10.11884/HPLPB201931.180245
Abstract:
The new RF system of Radio Frequency Quadrupole (RFQ) accelerator in ADS project at the Institute of Modern Physics (IMP) was upgraded in the beginning of 2017, the original tetrode amplifier was replaced by two new unconditionally stable solid-state amplifiers (SSAs) for proton acceleration, which have the same 80 kW nominal power and combine at least 120 kW inside the cavity with two uniform couplers. In the SSAs, the multiple power modules were amplitude-modulated and phase-optimized for power combination, but one or a couple of damaged circulators (including sink loads) might cause failure of the whole RF system. Especially, according to experiments and simulation, when the transmission line between the two different level combiners met a specific condition, the scattering parameter of the system would have great fluctuations, even cut-off, if damages occurred in circulators or sink loads. In this paper, the simulation methods for multi-level synthetic amplifying are introduced in detail; as a new design concept of the amplifier, the failure analysis and related experiments focusing on amplification links of SSA under special circumstances are also presented.
The new RF system of Radio Frequency Quadrupole (RFQ) accelerator in ADS project at the Institute of Modern Physics (IMP) was upgraded in the beginning of 2017, the original tetrode amplifier was replaced by two new unconditionally stable solid-state amplifiers (SSAs) for proton acceleration, which have the same 80 kW nominal power and combine at least 120 kW inside the cavity with two uniform couplers. In the SSAs, the multiple power modules were amplitude-modulated and phase-optimized for power combination, but one or a couple of damaged circulators (including sink loads) might cause failure of the whole RF system. Especially, according to experiments and simulation, when the transmission line between the two different level combiners met a specific condition, the scattering parameter of the system would have great fluctuations, even cut-off, if damages occurred in circulators or sink loads. In this paper, the simulation methods for multi-level synthetic amplifying are introduced in detail; as a new design concept of the amplifier, the failure analysis and related experiments focusing on amplification links of SSA under special circumstances are also presented.
2019,
31: 065104.
doi: 10.11884/HPLPB201931.180313
Abstract:
This paper introduces the stripline beam position monitor system we designed for the linac to ring beam transport(LRBT) of China Spallation Neutron Source(CSNS). The system's physical design and parameter optimization of monitor are done based on stripline type, mechanical calibration is done to reduce error caused by machining, and the electronic system is using a commercial data processing system. The system gives effective position data in actual accelerator running, and an analysis of online measurement data is done with SVD method. According to the analysis result, accuracy of beam orbit measurement has reached the intended design goal and can meet physical tuning needs.
This paper introduces the stripline beam position monitor system we designed for the linac to ring beam transport(LRBT) of China Spallation Neutron Source(CSNS). The system's physical design and parameter optimization of monitor are done based on stripline type, mechanical calibration is done to reduce error caused by machining, and the electronic system is using a commercial data processing system. The system gives effective position data in actual accelerator running, and an analysis of online measurement data is done with SVD method. According to the analysis result, accuracy of beam orbit measurement has reached the intended design goal and can meet physical tuning needs.
2019,
31: 066001.
doi: 10.11884/HPLPB201931.180330
Abstract:
HfO2 film with the thickness of 7.8nm is deposited on p type silicon by using atomic layer deposition method, and aluminum is sputtered on top of the HfO2 film to form Al/HfO2/Si MOS structure. The surface morphology of HfO2 is taken by using atomic force microscopy, and the surface quality is approved to be high with low surface roughness and high uniformity. The radiation induced oxide and interface trapped charge density are in the order of 1012cm-2, which is larger than that in SiO2 with the same equivalent oxide thickness. Moreover, the radiation induced oxide trapped charge density increases with the increase of irradiation total dose, the radiation induced interface trapped charge can be either positive or negative. The chemical structure of the HfO2 film is measured by XPS and oxygen vacancy is found to be the dominant radiation induced traps inside the film HfO2.
HfO2 film with the thickness of 7.8nm is deposited on p type silicon by using atomic layer deposition method, and aluminum is sputtered on top of the HfO2 film to form Al/HfO2/Si MOS structure. The surface morphology of HfO2 is taken by using atomic force microscopy, and the surface quality is approved to be high with low surface roughness and high uniformity. The radiation induced oxide and interface trapped charge density are in the order of 1012cm-2, which is larger than that in SiO2 with the same equivalent oxide thickness. Moreover, the radiation induced oxide trapped charge density increases with the increase of irradiation total dose, the radiation induced interface trapped charge can be either positive or negative. The chemical structure of the HfO2 film is measured by XPS and oxygen vacancy is found to be the dominant radiation induced traps inside the film HfO2.
