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RSS2017 Vol. 29, No. 11
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2017,
29: 110101.
doi: 10.11884/HPLPB201729.170217
Abstract:
This paper presents the high-power master-oscillator-main-amplifier(MOPA) structured superfluorescent fiber source(SFS) based on tandem pumping technology for high output power. Firstly, broadband seed source is generated from the home-made superfluorescent source with a full-width at half-maximum (FWHM) linewidth of 10.3 nm. Then, narrowband seed source with a FWHM linewidth of 1.8 nm is obtained by employing spectral filter. The narrowband seed light is enhanced to 104.4 W with the aid of two pre-amplifiers. As to the main amplification stage, the ultimate output power is 3.14 kW with an optical-to-optical conversion efficiency of 80.74%. The corresponding FWHM linewidth and M2 values of the amplified light are 4.68 nm and 1.59, respectively. Furthermore, the output power is only limited by the pump power, and further power scaling of this SFS system is available.
This paper presents the high-power master-oscillator-main-amplifier(MOPA) structured superfluorescent fiber source(SFS) based on tandem pumping technology for high output power. Firstly, broadband seed source is generated from the home-made superfluorescent source with a full-width at half-maximum (FWHM) linewidth of 10.3 nm. Then, narrowband seed source with a FWHM linewidth of 1.8 nm is obtained by employing spectral filter. The narrowband seed light is enhanced to 104.4 W with the aid of two pre-amplifiers. As to the main amplification stage, the ultimate output power is 3.14 kW with an optical-to-optical conversion efficiency of 80.74%. The corresponding FWHM linewidth and M2 values of the amplified light are 4.68 nm and 1.59, respectively. Furthermore, the output power is only limited by the pump power, and further power scaling of this SFS system is available.
2017,
29: 111001.
doi: 10.11884/HPLPB201729.170129
Abstract:
In order to understand the chemical etching process of fused silica, the reaction mechanism, processing parameters and the influence of HF etching on the etched surface quality are investigated. The effects of HF concentration, temperature and NH4F concentration on etching rate are obtained by performing the single factor experiment. The surface roughness, morphology, impurity content and damage threshold of the post-etched components are measured, and the experimental results indicate that the etching rate is influenced by a variety of factors, in which the effect of HF concentration is the greatest. The morphology of the HF-etched fused silica surface is complex, containing scratches, pits, impurities and other defects. And the main forms of defects are transverse and longitudinal scratches. The content of the main impurity defect decreases with the increase of etching time. The laser damage test shows that the damage threshold of fused silica is increased by 59.6% through the HF etching process.
In order to understand the chemical etching process of fused silica, the reaction mechanism, processing parameters and the influence of HF etching on the etched surface quality are investigated. The effects of HF concentration, temperature and NH4F concentration on etching rate are obtained by performing the single factor experiment. The surface roughness, morphology, impurity content and damage threshold of the post-etched components are measured, and the experimental results indicate that the etching rate is influenced by a variety of factors, in which the effect of HF concentration is the greatest. The morphology of the HF-etched fused silica surface is complex, containing scratches, pits, impurities and other defects. And the main forms of defects are transverse and longitudinal scratches. The content of the main impurity defect decreases with the increase of etching time. The laser damage test shows that the damage threshold of fused silica is increased by 59.6% through the HF etching process.
2017,
29: 111002.
doi: 10.11884/HPLPB201729.170110
Abstract:
High power semiconductor laser arrays (bars) have been widely used in many fields. Thermal stress induced by mismatch of thermal expansion coefficients between the bar and heat sink leads to smile effect. Larger smile can induce a lower beam quality which causes difficulty in collimation of laser beam. Thermal uniformity of the bar can be achieved by reducing temperature of the intermediate light emitting unit caused by thermal crosstalk. This paper presents the optimization of heat sink structure for temperature uniformity of the bar. Graphene on copper foil (GCF) with high thermal conductivity and two symmetrical holes (each beside an end of the foil) are adopted to optimize the traditional conduction cooled semiconductor (CS) heat sink. Numerical simulations on the thermal behavior of the CS-packaged bar show that, when the GCF foil is 8 mm long, the temperature difference is reduced from 7.94 ℃ to 3.65 ℃; the through holes cause temperature rise of emitters on both sides of the bar, and the temperature difference is further reduced to 3.18 ℃.
High power semiconductor laser arrays (bars) have been widely used in many fields. Thermal stress induced by mismatch of thermal expansion coefficients between the bar and heat sink leads to smile effect. Larger smile can induce a lower beam quality which causes difficulty in collimation of laser beam. Thermal uniformity of the bar can be achieved by reducing temperature of the intermediate light emitting unit caused by thermal crosstalk. This paper presents the optimization of heat sink structure for temperature uniformity of the bar. Graphene on copper foil (GCF) with high thermal conductivity and two symmetrical holes (each beside an end of the foil) are adopted to optimize the traditional conduction cooled semiconductor (CS) heat sink. Numerical simulations on the thermal behavior of the CS-packaged bar show that, when the GCF foil is 8 mm long, the temperature difference is reduced from 7.94 ℃ to 3.65 ℃; the through holes cause temperature rise of emitters on both sides of the bar, and the temperature difference is further reduced to 3.18 ℃.
2017,
29: 112001.
doi: 10.11884/HPLPB201729.170257
Abstract:
As an important diagnostic, Compton Radiography provides a means to measure the areal density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. How to mitigate background noise is very important but difficult. This paper analyzes each source of background noise in detail, and point out how to reduce the background noise, respectively. By optimizing the configuration of the detector and minimizing noise onto the detector, it will achieve 20 signal to noise ratio for neutron yields up to 1013 sr-1 and electron temperature of capsule core up to 5 keV, allowing fuel areal density to be measured with an accuracy of 5%.
As an important diagnostic, Compton Radiography provides a means to measure the areal density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. How to mitigate background noise is very important but difficult. This paper analyzes each source of background noise in detail, and point out how to reduce the background noise, respectively. By optimizing the configuration of the detector and minimizing noise onto the detector, it will achieve 20 signal to noise ratio for neutron yields up to 1013 sr-1 and electron temperature of capsule core up to 5 keV, allowing fuel areal density to be measured with an accuracy of 5%.
2017,
29: 113001.
doi: 10.11884/HPLPB201729.170133
Abstract:
Phase characteristic is one of the key parameters which limit the promotional applications of intense relativistic klystron amplifier. In order to reduce the phase jitter and improve the stability of device, an S-band intense relativistic klystron amplifier (RKA) with three cavities and annular beams is studied theoretically. The theoretical results indicate that fluctuation of intense pulse, self-oscillation, non-uniform of beam emission and transmission are the main reasons for phase fluctuation. Then some optimization works are done as follows: (1) The structure of diode are optimized to improve the uniformity of electric beams; (2) Microwave absorbing materials are added in the drift to suppress the self-oscillation; (3) On the condition of output power greater than GW level, the parameters of cavities are optimized to reduce the phase jitter caused by fluctuation of pulse voltage. At last, an experiment research is carried out on the LTD accelerator to confirm the effectiveness of optimization. The experiment results show: on the condition of output power greater than GW level, the standard deviation of output microwave phase is about 10 within 100 ns in single shot and about 20in 5 Hz repeat. The phase difference jetter between two RKAs is about 20.
Phase characteristic is one of the key parameters which limit the promotional applications of intense relativistic klystron amplifier. In order to reduce the phase jitter and improve the stability of device, an S-band intense relativistic klystron amplifier (RKA) with three cavities and annular beams is studied theoretically. The theoretical results indicate that fluctuation of intense pulse, self-oscillation, non-uniform of beam emission and transmission are the main reasons for phase fluctuation. Then some optimization works are done as follows: (1) The structure of diode are optimized to improve the uniformity of electric beams; (2) Microwave absorbing materials are added in the drift to suppress the self-oscillation; (3) On the condition of output power greater than GW level, the parameters of cavities are optimized to reduce the phase jitter caused by fluctuation of pulse voltage. At last, an experiment research is carried out on the LTD accelerator to confirm the effectiveness of optimization. The experiment results show: on the condition of output power greater than GW level, the standard deviation of output microwave phase is about 10 within 100 ns in single shot and about 20in 5 Hz repeat. The phase difference jetter between two RKAs is about 20.
2017,
29: 113002.
doi: 10.11884/HPLPB201729.170159
Abstract:
Accurate power coupler design is one of the key points to ensure high quality for RF gun used in FEL facility. In order to meet the design requirements of the RF gun, the simulation and test of coupling performance for the independent tunable RF gun applied in the HUST FEL-THz were conducted. First of all, the electromagnetic simulation software CST was used to calculate the RF gun both in frequency domain and eigenmode, and the results of these two methods are consistent with each other. The resonant frequencies are 2856.10 MHz and 2856.07 MHz respectively, while the coupling coefficients are 1.624 and 1.620. Additionally, the coupling performance of the RF gun which had been installed on the accelerator was measured by reflection coefficient method and cavity loss method respectively. The coupling coefficient of the 2nd cell is 1.78 and the resonant frequency is 2 855.77 MHz based on the former method on single point. Combined with both methods on this resonance point, the coupling coefficient is 1.785 by means of multipoint fitting. The results show that good agreements are achieved between simulations and measurements.
Accurate power coupler design is one of the key points to ensure high quality for RF gun used in FEL facility. In order to meet the design requirements of the RF gun, the simulation and test of coupling performance for the independent tunable RF gun applied in the HUST FEL-THz were conducted. First of all, the electromagnetic simulation software CST was used to calculate the RF gun both in frequency domain and eigenmode, and the results of these two methods are consistent with each other. The resonant frequencies are 2856.10 MHz and 2856.07 MHz respectively, while the coupling coefficients are 1.624 and 1.620. Additionally, the coupling performance of the RF gun which had been installed on the accelerator was measured by reflection coefficient method and cavity loss method respectively. The coupling coefficient of the 2nd cell is 1.78 and the resonant frequency is 2 855.77 MHz based on the former method on single point. Combined with both methods on this resonance point, the coupling coefficient is 1.785 by means of multipoint fitting. The results show that good agreements are achieved between simulations and measurements.
2017,
29: 113003.
doi: 10.11884/HPLPB201729.170097
Abstract:
In order to improve 3 dB axial ratio beamwidth (ARBW) of the microstrip antenna, a miniaturized wide 3 dB ARBW circularly polarized microstrip antenna is proposed, and it is designed by using the structure of bilayer dielectric substrates and the methods of grooving on radiation patches, feeding by single point coaxial probe and perturbing by truncated corners. The size of the antenna is 0.40800.40800.0360 at central wavelength (0), and the operating frequency covers IEEE 802.16e (3.5 GHz) frequency band. Using the simulation software (Ansoft HFSS15.0) based on finite element method to optimize and simulate the antenna, the design results show that 3 dB ARBW is 230~255, the band of voltage standing-wave ratio (VSWR) less than 2 is 290 MHz, the peak gain is 4.11 dB at 3.5 GHz. Also, the test results are in good agreement with the simulation results. So ARBW of antenna can be broadened by the proposed structure and method effectively.
In order to improve 3 dB axial ratio beamwidth (ARBW) of the microstrip antenna, a miniaturized wide 3 dB ARBW circularly polarized microstrip antenna is proposed, and it is designed by using the structure of bilayer dielectric substrates and the methods of grooving on radiation patches, feeding by single point coaxial probe and perturbing by truncated corners. The size of the antenna is 0.40800.40800.0360 at central wavelength (0), and the operating frequency covers IEEE 802.16e (3.5 GHz) frequency band. Using the simulation software (Ansoft HFSS15.0) based on finite element method to optimize and simulate the antenna, the design results show that 3 dB ARBW is 230~255, the band of voltage standing-wave ratio (VSWR) less than 2 is 290 MHz, the peak gain is 4.11 dB at 3.5 GHz. Also, the test results are in good agreement with the simulation results. So ARBW of antenna can be broadened by the proposed structure and method effectively.
2017,
29: 113004.
doi: 10.11884/HPLPB201729.170265
Abstract:
Based on the global model, within O- detachment process, the repetition frequency pulse relaxation model of high power microwave is rebuilt, and the relaxation process characteristics are analyzed. The relationship between electron density with time is simulated on different attachment frequency, detachment frequency and initial electron density. The results show that the electron density relaxation process is divided into the rapid-decay process and slow-decay process; electron density is significantly improved at the later stage of relaxation process. Detachment frequency and attachment frequency have opposite effects on the relaxation process. The higher the detachment frequency is, the higher electron density of the slow-decay process is, but electron density of the rapid-decay process doesnt change significantly. The higher the attachment frequency is, the sharper the change of the electron density on the rapid-decay process and the lower electron density in the slow-decay process is.
Based on the global model, within O- detachment process, the repetition frequency pulse relaxation model of high power microwave is rebuilt, and the relaxation process characteristics are analyzed. The relationship between electron density with time is simulated on different attachment frequency, detachment frequency and initial electron density. The results show that the electron density relaxation process is divided into the rapid-decay process and slow-decay process; electron density is significantly improved at the later stage of relaxation process. Detachment frequency and attachment frequency have opposite effects on the relaxation process. The higher the detachment frequency is, the higher electron density of the slow-decay process is, but electron density of the rapid-decay process doesnt change significantly. The higher the attachment frequency is, the sharper the change of the electron density on the rapid-decay process and the lower electron density in the slow-decay process is.
2017,
29: 113101.
doi: 10.11884/HPLPB201729.170096
Abstract:
Excitation of magnetic field with short pulse current coils is one of the important technological approaches for achieving ultra-strong magnetic field in high frequency vacuum electronic devices, in which eddy-current would be excited at the same time and influence the distribution of magnetic field inside the tube. Impact of eddy-current on the distribution of short pulse magnetic field is studied in this paper, the effects of pulse duration, conductivity and thickness of the metallic structure on eddy-current are analyzed. The results show that the influence of eddy current on the internal magnetic field increases with the decrease of the pulse width of the coil current, the increase of the conductivity and the thickness of the metal, which leads to failure of effective excitation of magnetic field inside the tube. Two methods for suppressing eddy current are proposed including electroplated coating of good conductor on high-resistivity metallic material and longitudinal slotting, the calculation results show that the two methods could effectively depress the influence of eddy-current on the distribution of magnetic field in the device.
Excitation of magnetic field with short pulse current coils is one of the important technological approaches for achieving ultra-strong magnetic field in high frequency vacuum electronic devices, in which eddy-current would be excited at the same time and influence the distribution of magnetic field inside the tube. Impact of eddy-current on the distribution of short pulse magnetic field is studied in this paper, the effects of pulse duration, conductivity and thickness of the metallic structure on eddy-current are analyzed. The results show that the influence of eddy current on the internal magnetic field increases with the decrease of the pulse width of the coil current, the increase of the conductivity and the thickness of the metal, which leads to failure of effective excitation of magnetic field inside the tube. Two methods for suppressing eddy current are proposed including electroplated coating of good conductor on high-resistivity metallic material and longitudinal slotting, the calculation results show that the two methods could effectively depress the influence of eddy-current on the distribution of magnetic field in the device.
2017,
29: 113201.
doi: 10.11884/HPLPB201729.170208
Abstract:
In order to study the shielding effectiveness of the unmanned aerial vehicle(UAV) enclosure, based on the numerical simulation software CST, the calculation model of the UAV enclosure was established, and the influence of electromagnetic wave radiation direction and polarization mode on the electromagnetic field distribution of the UAV was analyzed, the variation of shielding effectiveness with the electromagnetic parameters of the enclosure material was obtained. The method of testing the shielding effectiveness of the UAV enclosure using the frequency stirring reverberation chamber was proposed, the test procedure was given and the test system was built. The experimental results show that the method was effective. The results show that the frequency stirring reverberation chamber could get the statistics of the electromagnetic field in the enclosure of the UAV, and the shielding effectiveness of the enclosure in the 1-10 GHz band was about 8-10 dB. The probability of shielding effectiveness test results with deviation less than 3 dB of different measurement positions was 94%.
In order to study the shielding effectiveness of the unmanned aerial vehicle(UAV) enclosure, based on the numerical simulation software CST, the calculation model of the UAV enclosure was established, and the influence of electromagnetic wave radiation direction and polarization mode on the electromagnetic field distribution of the UAV was analyzed, the variation of shielding effectiveness with the electromagnetic parameters of the enclosure material was obtained. The method of testing the shielding effectiveness of the UAV enclosure using the frequency stirring reverberation chamber was proposed, the test procedure was given and the test system was built. The experimental results show that the method was effective. The results show that the frequency stirring reverberation chamber could get the statistics of the electromagnetic field in the enclosure of the UAV, and the shielding effectiveness of the enclosure in the 1-10 GHz band was about 8-10 dB. The probability of shielding effectiveness test results with deviation less than 3 dB of different measurement positions was 94%.
2017,
29: 113202.
doi: 10.11884/HPLPB201729.170216
Abstract:
High power electromagnetic pulse interference and even destruction of unmanned aerial vehicles is a very effective way to deal with the threat of small unmanned aerial vehicles (UAVs).The interference and damage of high power electromagnetic pulse to UAV system is mainly through the way of front door coupling and back door coupling. In this study, the damage of UAVs by high power electromagnetic pulse are analyzed, and the target vulnerability of UAVs under the electromagnetic pulse source is analyzed. According to the damage effect, the damage level of the high frequency electromagnetic pulse to UAVs is divided into three levels, namely the interference level, the damage level and the failure level, and the main targets of electromagnetic pulse are analyzed. The results show that the most vulnerable parts of the UAVs are the receiver and the electronic governor. Therefore, in future research and practical application, it is necessary to study the damage and destruction of the electromagnetic pulse to the receiver and the electronic governor. And the optimum frequency of damage should be determined based on the circuit configurations of the receiver and the electronic governor.
High power electromagnetic pulse interference and even destruction of unmanned aerial vehicles is a very effective way to deal with the threat of small unmanned aerial vehicles (UAVs).The interference and damage of high power electromagnetic pulse to UAV system is mainly through the way of front door coupling and back door coupling. In this study, the damage of UAVs by high power electromagnetic pulse are analyzed, and the target vulnerability of UAVs under the electromagnetic pulse source is analyzed. According to the damage effect, the damage level of the high frequency electromagnetic pulse to UAVs is divided into three levels, namely the interference level, the damage level and the failure level, and the main targets of electromagnetic pulse are analyzed. The results show that the most vulnerable parts of the UAVs are the receiver and the electronic governor. Therefore, in future research and practical application, it is necessary to study the damage and destruction of the electromagnetic pulse to the receiver and the electronic governor. And the optimum frequency of damage should be determined based on the circuit configurations of the receiver and the electronic governor.
2017,
29: 113203.
doi: 10.11884/HPLPB201729.170135
Abstract:
Normally, transmission lines uncertainty quantification analysis based on Monte Carlo (MC) method need very large number of samples. This paper chooses the polynomial chaos expansion (PCE) method to analyse the uncertainty quantification of random field coupling to transmission lines. In the case where input uncertain parameters are of non typical distributions, the corresponding orthogonal polynomial basis is constructed and the telegraph equation by PCE method is expanded. Finally, the statistical information of far end current is computed in the case of random field with two uncertain parameters coupling to transmission lines. It is proved that the PCE method is valid and more efficient compared with MC method.
Normally, transmission lines uncertainty quantification analysis based on Monte Carlo (MC) method need very large number of samples. This paper chooses the polynomial chaos expansion (PCE) method to analyse the uncertainty quantification of random field coupling to transmission lines. In the case where input uncertain parameters are of non typical distributions, the corresponding orthogonal polynomial basis is constructed and the telegraph equation by PCE method is expanded. Finally, the statistical information of far end current is computed in the case of random field with two uncertain parameters coupling to transmission lines. It is proved that the PCE method is valid and more efficient compared with MC method.
2017,
29: 113204.
doi: 10.11884/HPLPB201729.170215
Abstract:
This paper studies the effect of the initial values of different potentials on the surface potential attenuation of spacecraft dielectric materials. The method is as follows: charge the PI and PTFE dielectric materials to different potential values using spacecraft simulation equipment, then close the electron gun and measure the attenuation curve of the surface potential of the dielectric material with a potentiometer, and theoretically analyze the cross-over phenomenon. The result shows that, the higher the initial potential value of the dielectric material, the faster the surface potential decay rate, and the potential decay efficiency increases with the initial potential value in a certain period of time, under the same vacuum condition, for the two sets of attenuation curves with the same sum of initial potentials, the closer the initial potential values are, the more likely the cross-over phenomenon will occur; the time at which the cross-over occurs is related to the mobility of the electrons, under the same initial potentials, the longer the mobility, the shorter the time before the cross-over occur and the faster the potential attenuates. It is concluded that the values of the charge potential on the surface of the spacecraft affects the attenuation efficiency and the decay rate of the potential.
This paper studies the effect of the initial values of different potentials on the surface potential attenuation of spacecraft dielectric materials. The method is as follows: charge the PI and PTFE dielectric materials to different potential values using spacecraft simulation equipment, then close the electron gun and measure the attenuation curve of the surface potential of the dielectric material with a potentiometer, and theoretically analyze the cross-over phenomenon. The result shows that, the higher the initial potential value of the dielectric material, the faster the surface potential decay rate, and the potential decay efficiency increases with the initial potential value in a certain period of time, under the same vacuum condition, for the two sets of attenuation curves with the same sum of initial potentials, the closer the initial potential values are, the more likely the cross-over phenomenon will occur; the time at which the cross-over occurs is related to the mobility of the electrons, under the same initial potentials, the longer the mobility, the shorter the time before the cross-over occur and the faster the potential attenuates. It is concluded that the values of the charge potential on the surface of the spacecraft affects the attenuation efficiency and the decay rate of the potential.
2017,
29: 113205.
doi: 10.11884/HPLPB201729.170154
Abstract:
There are strong electromagnetic interferences on instantaneous electron beam parameters measurement system in LIA. The transient pulses, which may affect both circuits and measurement system, are harmful to electronic devices and capturing effective data. The principle of instantaneous electron beam parameters measurement system is introduced in this paper, while the formation mechanism and the suppression method of transient pulse interferences are analyzed. Arrangement of the system is also proposed. The effects on electron devices performance by transient pulse interference and the preventive method are discussed, too. By using optical fiber, which effectively reduced the delay jitter of narrow pulses, the reliability requirement of high-speed control signal propagation was fulfilled. To provide better protection for the electronic devices of beam parameter measurements, the anti-electromagnetic interference ability of the system was enhanced by compactly-embedded method. The reliability of the overall measurement system was significantly improved as a result.
There are strong electromagnetic interferences on instantaneous electron beam parameters measurement system in LIA. The transient pulses, which may affect both circuits and measurement system, are harmful to electronic devices and capturing effective data. The principle of instantaneous electron beam parameters measurement system is introduced in this paper, while the formation mechanism and the suppression method of transient pulse interferences are analyzed. Arrangement of the system is also proposed. The effects on electron devices performance by transient pulse interference and the preventive method are discussed, too. By using optical fiber, which effectively reduced the delay jitter of narrow pulses, the reliability requirement of high-speed control signal propagation was fulfilled. To provide better protection for the electronic devices of beam parameter measurements, the anti-electromagnetic interference ability of the system was enhanced by compactly-embedded method. The reliability of the overall measurement system was significantly improved as a result.
2017,
29: 113206.
doi: 10.11884/HPLPB201729.170272
Abstract:
Focusing on the concepts of joint electromagnetic spectrum operations(JEMSO) proposed by U.S. DoD, this paper fully analyzes the related electromagnetic operational environment(EMOE) from the viewpoints of JEMSO, complex electromagnetic environment(EME) and electromagnetic orders of battle(EOB); then points out that the compositions of newly proposed EMOE are actually similar to that of the complex EME well known by us；finally, it shows with case studies the weird complexity of EMOE effects.
Focusing on the concepts of joint electromagnetic spectrum operations(JEMSO) proposed by U.S. DoD, this paper fully analyzes the related electromagnetic operational environment(EMOE) from the viewpoints of JEMSO, complex electromagnetic environment(EME) and electromagnetic orders of battle(EOB); then points out that the compositions of newly proposed EMOE are actually similar to that of the complex EME well known by us；finally, it shows with case studies the weird complexity of EMOE effects.
2017,
29: 113207.
doi: 10.11884/HPLPB201729.170176
Abstract:
In the perspective of systematology, it is a complex system to solve the problem of system of systems (SoS) combat test. The concept and connotation of SoS were studied based on the basic theory of complex system, and a typical example of SoS was illustrated. On the basis of the demonstration and trait of complex system of SoS combat and SoS combat test, the complexity of SoS combat test was analyzed on two important items including non-linearity and emergency. Through analyzing the basic traits of custom performance test method, it was summarized that performance test method cannot adapt to SoS combat test from these traits, and the fundamental cause was that the reductionism did not adapt to the complexity of SoS combat test. The deficiency of performance test method was analyzed on methodology emphatically under the condition of SoS combat. Aiming at the deficiency of the performance test method on methodology, it was concluded that the methodology should be studied from the perspective of complex system in order to adapt to SoS combat test.
In the perspective of systematology, it is a complex system to solve the problem of system of systems (SoS) combat test. The concept and connotation of SoS were studied based on the basic theory of complex system, and a typical example of SoS was illustrated. On the basis of the demonstration and trait of complex system of SoS combat and SoS combat test, the complexity of SoS combat test was analyzed on two important items including non-linearity and emergency. Through analyzing the basic traits of custom performance test method, it was summarized that performance test method cannot adapt to SoS combat test from these traits, and the fundamental cause was that the reductionism did not adapt to the complexity of SoS combat test. The deficiency of performance test method was analyzed on methodology emphatically under the condition of SoS combat. Aiming at the deficiency of the performance test method on methodology, it was concluded that the methodology should be studied from the perspective of complex system in order to adapt to SoS combat test.
2017,
29: 113208.
doi: 10.11884/HPLPB201729.170262
Abstract:
With the increase of working frequency, electromagnetic interferences (EMI) become more and more serious for electronic equipment. High-speed connectors are the main interference sources. Numerical simulation of EMI/EMC for complicated communication system still suffers from many challenges such as too many complicated details, wideband frequency response, and inconsistency with real testing. In this paper, a simplified simulation model is proposed firstly with the aid of measurement and theory of reverberation. Then, a cooperative simulation is achieved through domain decomposition method (DDM). Furthermore, a superposition method is adopted to investigate the random effect brought by the uncertainty of transmission signals. The resonance and loss characteristics of chassis can be modeled exactly by the proposed method. Besides, the analysis of random effect is simplified. Consequently, the leakage field through the chassis is accurately predicted.
With the increase of working frequency, electromagnetic interferences (EMI) become more and more serious for electronic equipment. High-speed connectors are the main interference sources. Numerical simulation of EMI/EMC for complicated communication system still suffers from many challenges such as too many complicated details, wideband frequency response, and inconsistency with real testing. In this paper, a simplified simulation model is proposed firstly with the aid of measurement and theory of reverberation. Then, a cooperative simulation is achieved through domain decomposition method (DDM). Furthermore, a superposition method is adopted to investigate the random effect brought by the uncertainty of transmission signals. The resonance and loss characteristics of chassis can be modeled exactly by the proposed method. Besides, the analysis of random effect is simplified. Consequently, the leakage field through the chassis is accurately predicted.
2017,
29: 114101.
doi: 10.11884/HPLPB201729.170195
Abstract:
An S band narrowband bandpass filter bulk acoustic wave(BAW)with center frequency 2.460 GHz, bandwidth 41 MHz, band insertion loss -1.154 dB, passband ripple 0.9 dB, out of band rejection about -42.5 dB@2.385 GHz and -45.5 dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, each FBAR stack was designed in BAW filter by using Mason model, each FBARs shape was designed with the method of apodizied electrode. The acoustic-electromagnetic co-simulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and it has two characteristics: (1) an acoustic-electromagnetic(AEM) co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time;(2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and outputs necessary in-plane geometry information to the AEM co-simulation model.
An S band narrowband bandpass filter bulk acoustic wave(BAW)with center frequency 2.460 GHz, bandwidth 41 MHz, band insertion loss -1.154 dB, passband ripple 0.9 dB, out of band rejection about -42.5 dB@2.385 GHz and -45.5 dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, each FBAR stack was designed in BAW filter by using Mason model, each FBARs shape was designed with the method of apodizied electrode. The acoustic-electromagnetic co-simulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and it has two characteristics: (1) an acoustic-electromagnetic(AEM) co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time;(2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and outputs necessary in-plane geometry information to the AEM co-simulation model.
2017,
29: 115001.
doi: 10.11884/HPLPB201729.170189
Abstract:
Linear transformer driver (LTD) is a new electrical circuit topology developed in recent years which has a number of significant advantages such as compactness, flexible output parameters and high energy transfer efficiency. According to the requirement for flash X-ray radiography, the pulsed driver which can deliver 3 MV on a 40 rod pinch diode (RPD) has been designed. The machine is composed of 30 square pulse LTD stages in series with a total length of 8 meters. Each LTD stage contains 12 fundamental bricks each consisting of two 10 nF capacitors and a multi-gap switch connected in series and 4 harmonic bricks each consisting of two 1 nF capacitors and a multi-gap switch connected in series. The transformer oil is used as voltage adder insulator. According to the equivalent circuit simulation, the generator can produce more than 3 MV fast pulse in 16.8 ns with 98 ns FWHM.
Linear transformer driver (LTD) is a new electrical circuit topology developed in recent years which has a number of significant advantages such as compactness, flexible output parameters and high energy transfer efficiency. According to the requirement for flash X-ray radiography, the pulsed driver which can deliver 3 MV on a 40 rod pinch diode (RPD) has been designed. The machine is composed of 30 square pulse LTD stages in series with a total length of 8 meters. Each LTD stage contains 12 fundamental bricks each consisting of two 10 nF capacitors and a multi-gap switch connected in series and 4 harmonic bricks each consisting of two 1 nF capacitors and a multi-gap switch connected in series. The transformer oil is used as voltage adder insulator. According to the equivalent circuit simulation, the generator can produce more than 3 MV fast pulse in 16.8 ns with 98 ns FWHM.
2017,
29: 115002.
doi: 10.11884/HPLPB201729.170101
Abstract:
A compact type high power subnanosecond pulse former which is based on triple transmission line type pulse compression is presented in this paper. The pulse former is designed and simulations are carried out through adopting Pspice software, the simulation has verified the analysis. An experiment based on the pulse power generator CKP1000 has been made to study the complete pulse-compression system. The results show that when the input pulse width is 5 ns, the output pulse can be compressed to be 800 ps in half-width and the front edge is only 400 ps. The power gain is up to 1.8.
A compact type high power subnanosecond pulse former which is based on triple transmission line type pulse compression is presented in this paper. The pulse former is designed and simulations are carried out through adopting Pspice software, the simulation has verified the analysis. An experiment based on the pulse power generator CKP1000 has been made to study the complete pulse-compression system. The results show that when the input pulse width is 5 ns, the output pulse can be compressed to be 800 ps in half-width and the front edge is only 400 ps. The power gain is up to 1.8.
2017,
29: 115003.
doi: 10.11884/HPLPB201729.170130
Abstract:
To describe the operation mechanism of series resonant capacitor charging power supply(SR-CCPS) which is a high-order, multi-operating-mode nonlinear system visually, a hybrid automata model is built in this paper utilizing hybrid system theory. Based on the model, a piecewise linear(P-L) charging control method is proposed to realize multi-speed charging for S-R CCPS. The simulation results have verified the validation of the proposed model and method.
To describe the operation mechanism of series resonant capacitor charging power supply(SR-CCPS) which is a high-order, multi-operating-mode nonlinear system visually, a hybrid automata model is built in this paper utilizing hybrid system theory. Based on the model, a piecewise linear(P-L) charging control method is proposed to realize multi-speed charging for S-R CCPS. The simulation results have verified the validation of the proposed model and method.
2017,
29: 115004.
doi: 10.11884/HPLPB201729.170146
Abstract:
As a one-time miniaturized device used to generate and radiate electromagnetic pulse, the radio frequency explosive magnetic flux compression generator (RF MFCG) still has the bottle-neck in application because of the structure and properties of its radiation antenna. In order to solve this problem, the mechanism that the RF MFCG generates and radiates electromagnetic pulse is studied first in this paper. Then an RF MFCG miniaturization conformal antenna suitable for the actual demand is put forward on this basis. The antenna is designed to be a part of the body of the magnetic flux compression generator, which ensures the miniaturization and practicability of the device in terms of structure. The results of CST simulation and physical test show that the conformal antenna has good radiation characteristics in the frequency band of 0.5 GHz to 10.3 GHz, and it also can meet the practical demand of the RF MFCG in radiation performance.
As a one-time miniaturized device used to generate and radiate electromagnetic pulse, the radio frequency explosive magnetic flux compression generator (RF MFCG) still has the bottle-neck in application because of the structure and properties of its radiation antenna. In order to solve this problem, the mechanism that the RF MFCG generates and radiates electromagnetic pulse is studied first in this paper. Then an RF MFCG miniaturization conformal antenna suitable for the actual demand is put forward on this basis. The antenna is designed to be a part of the body of the magnetic flux compression generator, which ensures the miniaturization and practicability of the device in terms of structure. The results of CST simulation and physical test show that the conformal antenna has good radiation characteristics in the frequency band of 0.5 GHz to 10.3 GHz, and it also can meet the practical demand of the RF MFCG in radiation performance.
2017,
29: 115101.
doi: 10.11884/HPLPB201729.170258
Abstract:
This paper presents a new method to measure bunch length of linac with single cavity. Compared with the traditional way, the new method does not need reference cavity. Two eigenmodes of a rectangular cavity are utilized to measure bunch length, so that the improved device is simplified and compact. A single cavity bunch length monitor is designed for the National Synchrotron Radiation Laboratorys Tunable Infrared Laser for Fundamentals of Energy Chemistry. The positions of coaxial probes are optimized to avoid interference modes according to the electromagnetic field distribution. To control the working frequencies of the eigenmodes, the tuning screws are introduced in the cavity, and the method of dimension parameter optimization is put forward. A series of simulations based on CST is performed to verify the feasibility. The simulation results reveal that this monitor meets the requirements of bunch length measurement, and its relative error is less than 5%.
This paper presents a new method to measure bunch length of linac with single cavity. Compared with the traditional way, the new method does not need reference cavity. Two eigenmodes of a rectangular cavity are utilized to measure bunch length, so that the improved device is simplified and compact. A single cavity bunch length monitor is designed for the National Synchrotron Radiation Laboratorys Tunable Infrared Laser for Fundamentals of Energy Chemistry. The positions of coaxial probes are optimized to avoid interference modes according to the electromagnetic field distribution. To control the working frequencies of the eigenmodes, the tuning screws are introduced in the cavity, and the method of dimension parameter optimization is put forward. A series of simulations based on CST is performed to verify the feasibility. The simulation results reveal that this monitor meets the requirements of bunch length measurement, and its relative error is less than 5%.
2017,
29: 115102.
doi: 10.11884/HPLPB201729.170170
Abstract:
The injector Ⅰ of China Accelerator Driven Subcritical System (CADS) is composed of an ECR ion source, a low energy beam transport line, a radio frequency quadrupole accelerator, a medium energy beam transport line and cryomodules with SRF cavities to boost the beam energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam energy as well as beam current and beam losses. Though many of these are conventional designs, they can provide efficient operation of injector linac. This paper gives an overview of CADS linac beam instrumentation and a discussion of the system design.
The injector Ⅰ of China Accelerator Driven Subcritical System (CADS) is composed of an ECR ion source, a low energy beam transport line, a radio frequency quadrupole accelerator, a medium energy beam transport line and cryomodules with SRF cavities to boost the beam energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam energy as well as beam current and beam losses. Though many of these are conventional designs, they can provide efficient operation of injector linac. This paper gives an overview of CADS linac beam instrumentation and a discussion of the system design.
2017,
29: 116001.
doi: 10.11884/HPLPB201729.170155
Abstract:
To evaluate the detection cases and predict experiment results rapidly, a fast estimation model of neutron cell flux was established. Theoretically, the neutron cell flux in an enclosed space is inversely proportional to the square of the characteristic length, and the magnitude of neutron cell flux can reflect the intensity of scattering neutron flux. The neutron cell flux in enclosed experimental hall was calculated by Monte Carlo method, and the scattering neutron flux at different distances from neutron source was obtained. The relationship between the neutron cell flux and the hall size is obtained by fitting the simulation results. The relationship between the scattering neutron flux at different distances from neutron source x and the hall size L is also fitted, and the relative deviation between the fitting results and Monte Carlo simulation results is within 10%. The results show that the neutron cell flux in spherical structure is inversely proportional to the 1.905 power of the sphere radius; the neutron cell flux in strip experimental hall is inversely proportional to the 1.948 power of cross section width of experimental hall, also inversely proportional to the 0.775 power of ratio of length to width of experimental hall. The average track length of each single source neutron in spherical structure is 5 times the sphere radius, while in the enclosed experimental hall, the average track length of each source neutron is 2~3 times the characteristic size of experimental hall.
To evaluate the detection cases and predict experiment results rapidly, a fast estimation model of neutron cell flux was established. Theoretically, the neutron cell flux in an enclosed space is inversely proportional to the square of the characteristic length, and the magnitude of neutron cell flux can reflect the intensity of scattering neutron flux. The neutron cell flux in enclosed experimental hall was calculated by Monte Carlo method, and the scattering neutron flux at different distances from neutron source was obtained. The relationship between the neutron cell flux and the hall size is obtained by fitting the simulation results. The relationship between the scattering neutron flux at different distances from neutron source x and the hall size L is also fitted, and the relative deviation between the fitting results and Monte Carlo simulation results is within 10%. The results show that the neutron cell flux in spherical structure is inversely proportional to the 1.905 power of the sphere radius; the neutron cell flux in strip experimental hall is inversely proportional to the 1.948 power of cross section width of experimental hall, also inversely proportional to the 0.775 power of ratio of length to width of experimental hall. The average track length of each single source neutron in spherical structure is 5 times the sphere radius, while in the enclosed experimental hall, the average track length of each source neutron is 2~3 times the characteristic size of experimental hall.
2017,
29: 116002.
doi: 10.11884/HPLPB201729.170168
Abstract:
In nuclear neutronics/thermal-hydraulics coupling analysis, grid size will affect the speed and accuracy of calculation. This paper assesses the effect of the grid size on coupling results by establishing a PWR cell model at different levels of grid size and coupling calculation using the Monte Carlo neutron photon transport code MCNP5, the computation fluid dynamics code FLUENT, and our interface program MF_COUP. The relationship of grid temperature difference, grid density difference, and relative errors of the infinite neutron multiplier and power density distribution are demonstrated. The grid size causes errors less than 10-4 to keff and errors less than 1% to power distribution while the gird temperature difference of fuel is less than 50 K and the grid density difference of moderator is less than 3 kg/m3. Furthermore, a PWR single cell model and a PWR 33 cell model are calculated based on our mesh scheme. The results show that the using our mesh scheme is concise and effective while the total number of grid and computation time decrease significantly.
In nuclear neutronics/thermal-hydraulics coupling analysis, grid size will affect the speed and accuracy of calculation. This paper assesses the effect of the grid size on coupling results by establishing a PWR cell model at different levels of grid size and coupling calculation using the Monte Carlo neutron photon transport code MCNP5, the computation fluid dynamics code FLUENT, and our interface program MF_COUP. The relationship of grid temperature difference, grid density difference, and relative errors of the infinite neutron multiplier and power density distribution are demonstrated. The grid size causes errors less than 10-4 to keff and errors less than 1% to power distribution while the gird temperature difference of fuel is less than 50 K and the grid density difference of moderator is less than 3 kg/m3. Furthermore, a PWR single cell model and a PWR 33 cell model are calculated based on our mesh scheme. The results show that the using our mesh scheme is concise and effective while the total number of grid and computation time decrease significantly.
2017,
29: 116003.
doi: 10.11884/HPLPB201729.170139
Abstract:
To assess the radiation hardness of the power supply circuit, the models of electronic components and circuit were built based on Saber platform, and were validated by the testing circuits. Data of critical performance parameters were obtained by -dose experiments radiation of pivotal components. With these data, radiation hardness of power supply circuit was simulated, and data about critical performance parameter were obtained. On these bases, gamma-dose radiation hardness of power supply circuit was evaluated by quantification of margins and uncertainties (QMU) method, and the results were in good agreement with those obtained experimentally.
To assess the radiation hardness of the power supply circuit, the models of electronic components and circuit were built based on Saber platform, and were validated by the testing circuits. Data of critical performance parameters were obtained by -dose experiments radiation of pivotal components. With these data, radiation hardness of power supply circuit was simulated, and data about critical performance parameter were obtained. On these bases, gamma-dose radiation hardness of power supply circuit was evaluated by quantification of margins and uncertainties (QMU) method, and the results were in good agreement with those obtained experimentally.
2017,
29: 116004.
doi: 10.11884/HPLPB201729.170089
Abstract:
Tritium self-sufficiency of Z-pinch driven fusion-fission hybrid reactor (Z-FFR) is the basis of its long-term operation. In order to analyse the conditions of tritium self-sufficiency, a modified tritium fuel cycle model and equations of Z-FFR based on mean residence time calculation method were established. Through theoretical analysis and calculation, the tritium mass-flow of Z-pinch exhaust processing system(ZEP), tritium extraction system(TES), isotope separation system(ISS), water detriation system(WDS) were got. The results of tritium mass-flow are 52.30, 25.40, 81.30, 3.60 g/day, and tritium inventory are 52.30, 25.40, 8.13, 1.80 g. Meanwhile, criteria of tritium self-sufficiency were given out based on mass-flow. The design parameters can meet this requirements. Then the complementary relationship of burning rate, tritium breeding ratio and extraction efficiency under tritium self-sufficiency critical condition were analyzed.
Tritium self-sufficiency of Z-pinch driven fusion-fission hybrid reactor (Z-FFR) is the basis of its long-term operation. In order to analyse the conditions of tritium self-sufficiency, a modified tritium fuel cycle model and equations of Z-FFR based on mean residence time calculation method were established. Through theoretical analysis and calculation, the tritium mass-flow of Z-pinch exhaust processing system(ZEP), tritium extraction system(TES), isotope separation system(ISS), water detriation system(WDS) were got. The results of tritium mass-flow are 52.30, 25.40, 81.30, 3.60 g/day, and tritium inventory are 52.30, 25.40, 8.13, 1.80 g. Meanwhile, criteria of tritium self-sufficiency were given out based on mass-flow. The design parameters can meet this requirements. Then the complementary relationship of burning rate, tritium breeding ratio and extraction efficiency under tritium self-sufficiency critical condition were analyzed.
2017,
29: 116005.
doi: 10.11884/HPLPB201729.170244
Abstract:
In nuclear waste drum inspection by Segmented Gramma Scanning(SGS), the detector counts are different with the point sources at different positions during the rotation process, and the attenuation distance needs to be calibrated. We used the Matlabs data fitting method and numerical calculation method to get the corrected attenuation distance. The Monte-Carlo code was used to simulate the radionuclide in a waste barrel uniformly filled with polyethylene material with density of 1.0 g/cm3. Then the count distributions of 137Cs point sources at seven different locations in the barrel were obtained. The detector counts were simulated every 30 degrees on seven different rotational circles, and the corrected average attenuation distance was given by calculating the partial area with high contribution rate. The relative error of the activity estimation obtained by this method is between 0.6% and 25.2%. Compared to traditional methods (the relative error of the activity estimation is between 11.8% and 209.9%), the error is decreased obviously.
In nuclear waste drum inspection by Segmented Gramma Scanning(SGS), the detector counts are different with the point sources at different positions during the rotation process, and the attenuation distance needs to be calibrated. We used the Matlabs data fitting method and numerical calculation method to get the corrected attenuation distance. The Monte-Carlo code was used to simulate the radionuclide in a waste barrel uniformly filled with polyethylene material with density of 1.0 g/cm3. Then the count distributions of 137Cs point sources at seven different locations in the barrel were obtained. The detector counts were simulated every 30 degrees on seven different rotational circles, and the corrected average attenuation distance was given by calculating the partial area with high contribution rate. The relative error of the activity estimation obtained by this method is between 0.6% and 25.2%. Compared to traditional methods (the relative error of the activity estimation is between 11.8% and 209.9%), the error is decreased obviously.
2017,
29: 119001.
doi: 10.11884/HPLPB201729.170147
Abstract:
The selective laser melting (SLM) process of cobalt-chromium alloy and the effect of heat treatment on microstructure, mechanical properties were systematically studied. The orthogonal experiment was designed to optimize the process parameters by using EOS M290 SLM equipment. The microstructure, phase and mechanical properties were observed and tested by XRD, SEM, hardness tester and universal material testing machine. The results show that the optimum hatch distance is 0.08 mm, the scanning speed is 1110 mm/s, the laser power is 335W, the energy density is 4.8 J/mm2, the density is as high as 99.18%, and the optimum hatch angle is 67. The phase of Co-Cr alloy formed by SLM is mainly composed of (fcc) and a small amount of (hcp) phases, and the microstructure of the alloy consists of fine uniform cell crystal and columnar crystal. The hardness, tensile strength and elongation of the Co-Cr alloy formed by SLM are 41.0 HRC, 1032 MPa, 10%, and the main fracture is transgranular ductile fracture. After heat treatment, the phase transition will occur, the microstructure is mainly composed of phase and a small amount of phase, and produces a small amount of an enhanced phase M23C6(M=Cr, Mo, W); the hardness, tensile strength and elongation are increased by 6.1%, 35.9% and 17.6%, respectively; the main fracture is quasi-cleavage fracture.
The selective laser melting (SLM) process of cobalt-chromium alloy and the effect of heat treatment on microstructure, mechanical properties were systematically studied. The orthogonal experiment was designed to optimize the process parameters by using EOS M290 SLM equipment. The microstructure, phase and mechanical properties were observed and tested by XRD, SEM, hardness tester and universal material testing machine. The results show that the optimum hatch distance is 0.08 mm, the scanning speed is 1110 mm/s, the laser power is 335W, the energy density is 4.8 J/mm2, the density is as high as 99.18%, and the optimum hatch angle is 67. The phase of Co-Cr alloy formed by SLM is mainly composed of (fcc) and a small amount of (hcp) phases, and the microstructure of the alloy consists of fine uniform cell crystal and columnar crystal. The hardness, tensile strength and elongation of the Co-Cr alloy formed by SLM are 41.0 HRC, 1032 MPa, 10%, and the main fracture is transgranular ductile fracture. After heat treatment, the phase transition will occur, the microstructure is mainly composed of phase and a small amount of phase, and produces a small amount of an enhanced phase M23C6(M=Cr, Mo, W); the hardness, tensile strength and elongation are increased by 6.1%, 35.9% and 17.6%, respectively; the main fracture is quasi-cleavage fracture.
