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RSS2018 Vol. 30, No. 1
Recommend Articles
column
- Project Progress Report
- Research Letter
- High Power Laser and Optics
- ICF and Laser Plasma
- High Power Microwave
- Terahertz Technology
- Complex Electromagnetic Environment
- Particle Beams Technology
- Micro-nano Technology
- Pulsed Power Technology
- Accelerator Technology
- Nuclear Science and Engineering
- Applications of Laser and Particle Beams
- 本期封面及目录
Display Method:
2018,
30: 010101.
doi: 10.11884/HPLPB201830.170466
Abstract:
A new-type of (8+1) GT-wave fiber was fabricated by our newly-optimized specialty fiber assembly and coating techniques for the first time. This (8+1) GT-wave fiber allowed for 10.66 kW aggregated pump power at 976 nm from 6 counter-pump-ports in a master oscillator power amplifier (MOPA) laser setup and stably presented 8.72 kW laser output at 1 079.4 nm with a high optical-to-optical efficiency of 81.0%. This is the highest power of the fiber amplifiers pumped by commercial laser diodes that has been reported so far, and only limited by the available pump power. Up to this power level, pure output spectrum with narrow 3 dB bandwidth Δλ3 dB of 2.76 nm and without any sign of stimulated Raman scattering and amplified spontaneous emission was obtained. With other ten pump-ports to collect more pump power, a further power scaling towards 10 kW or above can be expected.
A new-type of (8+1) GT-wave fiber was fabricated by our newly-optimized specialty fiber assembly and coating techniques for the first time. This (8+1) GT-wave fiber allowed for 10.66 kW aggregated pump power at 976 nm from 6 counter-pump-ports in a master oscillator power amplifier (MOPA) laser setup and stably presented 8.72 kW laser output at 1 079.4 nm with a high optical-to-optical efficiency of 81.0%. This is the highest power of the fiber amplifiers pumped by commercial laser diodes that has been reported so far, and only limited by the available pump power. Up to this power level, pure output spectrum with narrow 3 dB bandwidth Δλ3 dB of 2.76 nm and without any sign of stimulated Raman scattering and amplified spontaneous emission was obtained. With other ten pump-ports to collect more pump power, a further power scaling towards 10 kW or above can be expected.
2018,
30: 010102.
doi: 10.11884/HPLPB201830.170424
Abstract:
The continuous wave laser oscillation of optically pumped metastable Ar laser was observed. By employing a narrow linewidth diode laser based on volume Bragg grating as the pump source and He-Ar RF capacitive discharge plasma at 0.08 MPa as the gain medium, the power of 912.3 nm output laser was measured to be 0.22 mW from a laser cavity based on a longitudinally double-pass-pumped configuration.
The continuous wave laser oscillation of optically pumped metastable Ar laser was observed. By employing a narrow linewidth diode laser based on volume Bragg grating as the pump source and He-Ar RF capacitive discharge plasma at 0.08 MPa as the gain medium, the power of 912.3 nm output laser was measured to be 0.22 mW from a laser cavity based on a longitudinally double-pass-pumped configuration.
2018,
30: 011001.
doi: 10.11884/HPLPB201830.170295
Abstract:
Based on the jet polishing mechanism of single nozzle structure, the impact caused by the variations of particle diameter and polishing liquid concentration is studied. In consideration of the actual manufacture process, the particle diameters is nonuniform, thus a theoretical model has been established to discuss the material removal characteristic at the non-ideal condition.The impact of different particle size distribution on the material removal characteristics is mainly investigated. The results show that the material removal amount decreases with the increase of particle diameters, it increases with the increase of the mass concentration of the polishing solution. In addition, when the particle size is randomly distributed, significant fluctuation appears in material removal. The magnitude of the fluctuation is directly related to the average diameter of the polishing particles. Compared with the ideal uniform distribution, the removal amount caused by the un-uniform particles is relatively bigger.
Based on the jet polishing mechanism of single nozzle structure, the impact caused by the variations of particle diameter and polishing liquid concentration is studied. In consideration of the actual manufacture process, the particle diameters is nonuniform, thus a theoretical model has been established to discuss the material removal characteristic at the non-ideal condition.The impact of different particle size distribution on the material removal characteristics is mainly investigated. The results show that the material removal amount decreases with the increase of particle diameters, it increases with the increase of the mass concentration of the polishing solution. In addition, when the particle size is randomly distributed, significant fluctuation appears in material removal. The magnitude of the fluctuation is directly related to the average diameter of the polishing particles. Compared with the ideal uniform distribution, the removal amount caused by the un-uniform particles is relatively bigger.
Focusing properties of power-exponent-phase vortex beam focused by high numerical-aperture objective
2018,
30: 011002.
doi: 10.11884/HPLPB201830.170259
Abstract:
Based on vectorial Debye theory, the focusing properties of linearly polarized power-exponent-phase vortex beam focused by a high numerical aperture objective is studied. The influence of the topological charge and power index on the focal intensity and the phase of x-component is investigated in detail. The result shows that different types of focal intensity distribution, such as dark-core shape focal beam with beam size of 2 wavelength, can be generated by controlling the topological charge and power index. In particular, it is found that the phase singularity of power-exponent phase vortex beam has a deviation from the geometrical focus. The potential applications of this study may include particle manipulation.
Based on vectorial Debye theory, the focusing properties of linearly polarized power-exponent-phase vortex beam focused by a high numerical aperture objective is studied. The influence of the topological charge and power index on the focal intensity and the phase of x-component is investigated in detail. The result shows that different types of focal intensity distribution, such as dark-core shape focal beam with beam size of 2 wavelength, can be generated by controlling the topological charge and power index. In particular, it is found that the phase singularity of power-exponent phase vortex beam has a deviation from the geometrical focus. The potential applications of this study may include particle manipulation.
2018,
30: 012001.
doi: 10.11884/HPLPB201830.170269
Abstract:
An effective unconditionally stable implementation of the auxiliary differential equation Crank-Nicolson-approximate-decoupling finite-difference time-domain (ADE-CNAD-FDTD) algorithm for 2-D anisotropic magnetized plasma is proposed. The conventional ADE-FDTD method for 1-D anisotropic dispersive media has high efficiency and accuracy. This paper extends this method to 2-D anisotropic magnetized plasma with the CNAD scheme. The proposed formulations not only solves the problem that incorporates both anisotropy and frequency dispersion at the same time, but also eliminates the Courant-Friedrich-Levy (CFL) stability constraint. A numerical example has been carried out to validate the proposed formulations in the 2-D FDTD domain composed of anisotropic magnetized plasma. The results prove that the proposed formulations significantly save time and perform stably with acceptable accuracy.
An effective unconditionally stable implementation of the auxiliary differential equation Crank-Nicolson-approximate-decoupling finite-difference time-domain (ADE-CNAD-FDTD) algorithm for 2-D anisotropic magnetized plasma is proposed. The conventional ADE-FDTD method for 1-D anisotropic dispersive media has high efficiency and accuracy. This paper extends this method to 2-D anisotropic magnetized plasma with the CNAD scheme. The proposed formulations not only solves the problem that incorporates both anisotropy and frequency dispersion at the same time, but also eliminates the Courant-Friedrich-Levy (CFL) stability constraint. A numerical example has been carried out to validate the proposed formulations in the 2-D FDTD domain composed of anisotropic magnetized plasma. The results prove that the proposed formulations significantly save time and perform stably with acceptable accuracy.
2018,
30: 013001.
doi: 10.11884/HPLPB201830.170188
Abstract:
In order to achieve beam steering of mechanical phased array antenna, the brushed direct current motor(BDCM) is adopted to drive a helical antenna element to rotate to a predetermined radiation. The design and implementation of a multi-axis BDCM controller using a field programmable gate array (FPGA) is studied. Based on IP core design methodology, the flexibility of the system on a Programmable Chip(SoPC) in multiple-axis BDCM controller enables the processing of the most position servo control operations by hardware(BDCM controller IP core) and the trajectory computation and communication operations by software (Nios II microprocessor) in the same device. A high performance BDCM controller IP core described in Verilog HDL is designed, and simulation is fulfilled. The reusability of the IP core is demonstrated with the design of a 56 axis SoPC system. The experimental results show that the system can realize high precision control of the 56 axis BDCM, each axis is independent of the others, all parameters are programmable online, and consistency meets the system requirement. The built-up system based on this mode has many advantages, such as easy expansion, high portability and broad applicability. It has been applied to a phased array antenna.
In order to achieve beam steering of mechanical phased array antenna, the brushed direct current motor(BDCM) is adopted to drive a helical antenna element to rotate to a predetermined radiation. The design and implementation of a multi-axis BDCM controller using a field programmable gate array (FPGA) is studied. Based on IP core design methodology, the flexibility of the system on a Programmable Chip(SoPC) in multiple-axis BDCM controller enables the processing of the most position servo control operations by hardware(BDCM controller IP core) and the trajectory computation and communication operations by software (Nios II microprocessor) in the same device. A high performance BDCM controller IP core described in Verilog HDL is designed, and simulation is fulfilled. The reusability of the IP core is demonstrated with the design of a 56 axis SoPC system. The experimental results show that the system can realize high precision control of the 56 axis BDCM, each axis is independent of the others, all parameters are programmable online, and consistency meets the system requirement. The built-up system based on this mode has many advantages, such as easy expansion, high portability and broad applicability. It has been applied to a phased array antenna.
2018,
30: 013002.
doi: 10.11884/HPLPB201830.170158
Abstract:
With the smart grid becoming a national strategy, the security and reliability of the high speed and integration optical fiber communication network has become a key problem we need to focus on. But the fiber converter widely used in the power grid has no protection from high power electromagnetic pulse. If it is interfered or damaged, the whole communication network and power grid may be threatened. To study this problem, the thesis presents the test and analysis on a kind of commonly used fiber converter. Through the high power microwave radiation tests, we found the fiber converter might be disturbed or damaged in a low electromagnetic environment. Through further coupling simulation analysis and mechanism study of typical semiconductor device, it is determined that the main energy coupling channel is heat emission holes, and the coupling energy in L band would be at least an order of magnitude greater than that in S band. Coupling energy works mainly on conversion IC chips by field-circuit coupling, and the intrinsic reason might be the latch-up effect of semiconductor devices.
With the smart grid becoming a national strategy, the security and reliability of the high speed and integration optical fiber communication network has become a key problem we need to focus on. But the fiber converter widely used in the power grid has no protection from high power electromagnetic pulse. If it is interfered or damaged, the whole communication network and power grid may be threatened. To study this problem, the thesis presents the test and analysis on a kind of commonly used fiber converter. Through the high power microwave radiation tests, we found the fiber converter might be disturbed or damaged in a low electromagnetic environment. Through further coupling simulation analysis and mechanism study of typical semiconductor device, it is determined that the main energy coupling channel is heat emission holes, and the coupling energy in L band would be at least an order of magnitude greater than that in S band. Coupling energy works mainly on conversion IC chips by field-circuit coupling, and the intrinsic reason might be the latch-up effect of semiconductor devices.
2018,
30: 013003.
doi: 10.11884/HPLPB201830.170289
Abstract:
Beam steering system serves as the nerve center of high power phased array antenna, and it is responsible for the precise phase control and status monitoring of all element in antenna array. To achieve fast and accurate beam steering conversion, two level distributed beam steering scheme is designed using distributed topology and embedded real-time operating system VxWorks, and beam steering host system of phased array antenna based on VxWorks is developed. Multi-node network communication between beam steering host system and other systems is achieved via UDP protocol, and VxWorks multitask programming interface is utilized to design a Socket communication method based on the buffering queue to meet the high-speed and real-time communication demands, and a custom application layer protocol is designed for parties to accurately interpret communications. Feasibility of the scheme and reliability and stability of the control software have been verified through developing and applying the phased array antenna beam steering host system based on VxWorks.
Beam steering system serves as the nerve center of high power phased array antenna, and it is responsible for the precise phase control and status monitoring of all element in antenna array. To achieve fast and accurate beam steering conversion, two level distributed beam steering scheme is designed using distributed topology and embedded real-time operating system VxWorks, and beam steering host system of phased array antenna based on VxWorks is developed. Multi-node network communication between beam steering host system and other systems is achieved via UDP protocol, and VxWorks multitask programming interface is utilized to design a Socket communication method based on the buffering queue to meet the high-speed and real-time communication demands, and a custom application layer protocol is designed for parties to accurately interpret communications. Feasibility of the scheme and reliability and stability of the control software have been verified through developing and applying the phased array antenna beam steering host system based on VxWorks.
2018,
30: 013004.
doi: 10.11884/HPLPB201830.170210
Abstract:
The one-dimensional system generated electromagnetic pulse(SGEMP) boundary layer is simulated by PIC code of quasi-first principle. The SGEMP effects of monoenergetic emission model are studied—the photoelectrons are emitted normally at 3.3×1020m-2·s-1 all with 2 keV energy from infinitely large dielectric plane while positive charges are left on the plane. When the steady state is reached, the maximum distance the electrons travel is oscillating between 5.8 cm and 7.5 cm, the charge density at z=0 is oscillating within (6.0-9.0)×10－6C/m3 and electric field at the surface is 50-55kV/m. The build-up time of quasi-steady state is 14.0 ns. The simulation results of steady state accord with the theoretic results, and the simulation results could image the forming process and the adiabatic oscillation of the steady state more clearly than the theoretic results. The modeling by PIC code to study SGEMP effects is validated.
The one-dimensional system generated electromagnetic pulse(SGEMP) boundary layer is simulated by PIC code of quasi-first principle. The SGEMP effects of monoenergetic emission model are studied—the photoelectrons are emitted normally at 3.3×1020m-2·s-1 all with 2 keV energy from infinitely large dielectric plane while positive charges are left on the plane. When the steady state is reached, the maximum distance the electrons travel is oscillating between 5.8 cm and 7.5 cm, the charge density at z=0 is oscillating within (6.0-9.0)×10－6C/m3 and electric field at the surface is 50-55kV/m. The build-up time of quasi-steady state is 14.0 ns. The simulation results of steady state accord with the theoretic results, and the simulation results could image the forming process and the adiabatic oscillation of the steady state more clearly than the theoretic results. The modeling by PIC code to study SGEMP effects is validated.
2018,
30: 013101.
doi: 10.11884/HPLPB201830.170276
Abstract:
With regard to "blackout" problems in aircraft, the transmission characteristics of terahertz (THz) waves in magnetized and homogeneous plasma were studied. Within the established framework of the electromagnetic wave which is inclined to the magnetized plasma transfer model, we compared different performances of terahertz waves in the magnetized plasma, by changing the reflection, the transmission, and the attenuation of their transmission. The simulation results show that the plasma collision frequency, electron density, incident angle and magnetic field intensity have different effects on attenuation. The attenuation value increases at first then decreases when the collision frequency is simply increased. The increase of electron density increases the peak value of the attenuation. Attenuation value decreases with addition of external magnetic field. Thus the "blackout" problem can be effectively solved by applying constant external magnetic field.
With regard to "blackout" problems in aircraft, the transmission characteristics of terahertz (THz) waves in magnetized and homogeneous plasma were studied. Within the established framework of the electromagnetic wave which is inclined to the magnetized plasma transfer model, we compared different performances of terahertz waves in the magnetized plasma, by changing the reflection, the transmission, and the attenuation of their transmission. The simulation results show that the plasma collision frequency, electron density, incident angle and magnetic field intensity have different effects on attenuation. The attenuation value increases at first then decreases when the collision frequency is simply increased. The increase of electron density increases the peak value of the attenuation. Attenuation value decreases with addition of external magnetic field. Thus the "blackout" problem can be effectively solved by applying constant external magnetic field.
2018,
30: 013201.
doi: 10.11884/HPLPB201830.170270
Abstract:
The orientation of corona discharge radiant point was mostly realized by time difference orientation method based on the time-delay estimation. On the testing locales, the precision of the time-delay estimation was influenced by various background noise and interferential signals. The time-delay estimation method of generalized cross correlation was researched in this paper based on analyzing the domestic and international research dynamic state, which aimed at the localization of the basic cross correlation time-delay estimation, such as the low resolution definition and the weak robustness, etc. The time-delay estimation method which was suitable for the corona discharge radiation signal was searched by simulation comparing and experiment validating based on adopting different weight function. The research indicated that the time-delay estimation method of generalized cross correlation based on weighted Hassab-Boucher (HB) had the best restraining effect and highest precision for the periodicity interferential signals in the reality testing environment, and the error of the time-delay estimation was 4.5%. It was feasible to carry out the time-delay estimation and far distance orientation of the corona signals in the actual engineering application.
The orientation of corona discharge radiant point was mostly realized by time difference orientation method based on the time-delay estimation. On the testing locales, the precision of the time-delay estimation was influenced by various background noise and interferential signals. The time-delay estimation method of generalized cross correlation was researched in this paper based on analyzing the domestic and international research dynamic state, which aimed at the localization of the basic cross correlation time-delay estimation, such as the low resolution definition and the weak robustness, etc. The time-delay estimation method which was suitable for the corona discharge radiation signal was searched by simulation comparing and experiment validating based on adopting different weight function. The research indicated that the time-delay estimation method of generalized cross correlation based on weighted Hassab-Boucher (HB) had the best restraining effect and highest precision for the periodicity interferential signals in the reality testing environment, and the error of the time-delay estimation was 4.5%. It was feasible to carry out the time-delay estimation and far distance orientation of the corona signals in the actual engineering application.
2018,
30: 013202.
doi: 10.11884/HPLPB201830.170193
Abstract:
The high resolution simulation of cloud-to-ground lightning leaders on sea surface is presented based on two-dimensional leader progression model, and the fine image of the development process of the lightning leader is acquired. Through the establishment of two-dimensional model of ship, and according to the related standards of ship, the number and height and position of lightning rod are determined, and their lightning protection area is evaluated using proposed method. The test data show that when the ship adopts the single lightning rod protection, the probability of lightning strike is obviously increased, and the protection effect is better in the vicinity of the lightning rod. Compared with the single rod scheme, when the ship adopts double lightning rod protection the overall structure height of the ship is reduced, total number of lightning flashes on the ship will be reduced, and the protective effect will be better. With the development of long air gap discharge test and lightning observation, the protection analysis method will be more thorough and accurate.
The high resolution simulation of cloud-to-ground lightning leaders on sea surface is presented based on two-dimensional leader progression model, and the fine image of the development process of the lightning leader is acquired. Through the establishment of two-dimensional model of ship, and according to the related standards of ship, the number and height and position of lightning rod are determined, and their lightning protection area is evaluated using proposed method. The test data show that when the ship adopts the single lightning rod protection, the probability of lightning strike is obviously increased, and the protection effect is better in the vicinity of the lightning rod. Compared with the single rod scheme, when the ship adopts double lightning rod protection the overall structure height of the ship is reduced, total number of lightning flashes on the ship will be reduced, and the protective effect will be better. With the development of long air gap discharge test and lightning observation, the protection analysis method will be more thorough and accurate.
2018,
30: 013203.
doi: 10.11884/HPLPB201830.170273
Abstract:
Mono-static and bi-static radar cross sections (RCS) of target reflect that whether the target could be separately detected by mono-static and bi-static radars easily. Currently, there is no quantitative index for comparison between mono-static and bi-static RCS. In this paper, definitions of RCS enhancement factor and RCS enhancement ratio of bi-static RCS relative to mono-static are given at first. Then, the two definitions are applied to analyze bi-static RCS of some stealth target and non-stealth target. The result shows that, the RCS enhancement factor is big and RCS enhancement ratio is high for stealth target, but the factor is small and the ratio is low for non-stealth target. Combined with meaning of the two indexes, it can be found that, utilization of bi-static RCS is helpful for detection of stealth target, but this effect is not obvious for non-stealth target, which is consistent with the understanding of the radar community. This also shows that the application of the above two indexes in comparison analysis between mono-static RCS and bi-static RCS is effective. In addition, according to the analysis result of bi-static RCS in narrow bi-static angle for stealth target, the detection effect can be improved when bi-static RCS in bi-static angle range from 20° to 40° is used.
Mono-static and bi-static radar cross sections (RCS) of target reflect that whether the target could be separately detected by mono-static and bi-static radars easily. Currently, there is no quantitative index for comparison between mono-static and bi-static RCS. In this paper, definitions of RCS enhancement factor and RCS enhancement ratio of bi-static RCS relative to mono-static are given at first. Then, the two definitions are applied to analyze bi-static RCS of some stealth target and non-stealth target. The result shows that, the RCS enhancement factor is big and RCS enhancement ratio is high for stealth target, but the factor is small and the ratio is low for non-stealth target. Combined with meaning of the two indexes, it can be found that, utilization of bi-static RCS is helpful for detection of stealth target, but this effect is not obvious for non-stealth target, which is consistent with the understanding of the radar community. This also shows that the application of the above two indexes in comparison analysis between mono-static RCS and bi-static RCS is effective. In addition, according to the analysis result of bi-static RCS in narrow bi-static angle for stealth target, the detection effect can be improved when bi-static RCS in bi-static angle range from 20° to 40° is used.
2018,
30: 013204.
doi: 10.11884/HPLPB201830.170194
Abstract:
This paper studies the principle of radio frequency limiting of PIN, and analyzes how the spike leakage occurs in EMP protection and how to restrain it. On this basis, the structure of passive multi-stage PIN diode is adopted. Through the establishment of its field simulation model, the corresponding S parameters are extracted, and the optimal matching network is optimized. The electromagnetic pulse protection module which works at 1-200 MHz with insertion loss of less than 0.15 dB, VSWR of less than 1.4 dB, response time of less than 1ns is designed. Combined with PIN diode model, ADS simulation software is used to simulate the limiting performance of electromagnetic pulse protection module. The result shows that all the indexes meet the requirements.
This paper studies the principle of radio frequency limiting of PIN, and analyzes how the spike leakage occurs in EMP protection and how to restrain it. On this basis, the structure of passive multi-stage PIN diode is adopted. Through the establishment of its field simulation model, the corresponding S parameters are extracted, and the optimal matching network is optimized. The electromagnetic pulse protection module which works at 1-200 MHz with insertion loss of less than 0.15 dB, VSWR of less than 1.4 dB, response time of less than 1ns is designed. Combined with PIN diode model, ADS simulation software is used to simulate the limiting performance of electromagnetic pulse protection module. The result shows that all the indexes meet the requirements.
2018,
30: 013205.
doi: 10.11884/HPLPB201830.170291
Abstract:
In order to solve the problem of the poor correlation of the radiation susceptibility test results between uniform field and reverberation chamber, this paper analyzes the statistical characteristics of the E-field rectangular component and the antenna's received power in reverberation chamber with statistical theory, and a calculation model of critical radiated interference E-field intensity base on the failure probability of equipment under test is derived. To verify the correctness of the calculation model, the ETS 3142E antenna is taken as equipment under test to perform the critical radiated interference E-field intensity test in uniform field and reverberation chamber. The experiment result shows that the critical radiated interference E-field intensity obtained by the calculation model is well consistent with the test result in uniform field, and the average relative error can be decreased to 2 dB, which indicates that this calculation model can be applied to' actual radiation susceptibility test.
In order to solve the problem of the poor correlation of the radiation susceptibility test results between uniform field and reverberation chamber, this paper analyzes the statistical characteristics of the E-field rectangular component and the antenna's received power in reverberation chamber with statistical theory, and a calculation model of critical radiated interference E-field intensity base on the failure probability of equipment under test is derived. To verify the correctness of the calculation model, the ETS 3142E antenna is taken as equipment under test to perform the critical radiated interference E-field intensity test in uniform field and reverberation chamber. The experiment result shows that the critical radiated interference E-field intensity obtained by the calculation model is well consistent with the test result in uniform field, and the average relative error can be decreased to 2 dB, which indicates that this calculation model can be applied to' actual radiation susceptibility test.
2018,
30: 013206.
doi: 10.11884/HPLPB201830.170172
Abstract:
The mesoband high power electromagnetic pulse is a main development direction of high power microwave technology in recent years, the simulator can be used in the research of radiation environment simulation and effect study of high power electromagnetic pulse.This paper reports the survey of the mesoband high power electromagnetic pulse simulator and the common characteristics of the simulator in the working frequency and technical mode. A mesoband high power electromagnetic pulse is described, in the design, the mesoband antenna can be driven by a Marx generator directly. According to the experimental results of the simulator, the wide spectrum radiation factor is 224 kV, the repetition frequency is 40 Hz, the center radiation frequency is 215 MHz, and the spectrum width is 32%. It is concluded that the design requirement is well satisfied, the simulator can provide reference and test foundation for further development and scientific research.
The mesoband high power electromagnetic pulse is a main development direction of high power microwave technology in recent years, the simulator can be used in the research of radiation environment simulation and effect study of high power electromagnetic pulse.This paper reports the survey of the mesoband high power electromagnetic pulse simulator and the common characteristics of the simulator in the working frequency and technical mode. A mesoband high power electromagnetic pulse is described, in the design, the mesoband antenna can be driven by a Marx generator directly. According to the experimental results of the simulator, the wide spectrum radiation factor is 224 kV, the repetition frequency is 40 Hz, the center radiation frequency is 215 MHz, and the spectrum width is 32%. It is concluded that the design requirement is well satisfied, the simulator can provide reference and test foundation for further development and scientific research.
2018,
30: 013207.
doi: 10.11884/HPLPB201830.170213
Abstract:
The vortex electromagnetic wave has the characteristic of carrying orbital angular momentum. Based on this feature, vortex electromagnetic waves are used as signal carrier to achieve multi-channel signal simultaneous transmission within the same frequency band, which greatly improves the system capacity and bandwidth utilization. In this paper, by utilizing the circular microstrip antenna with a semicircular slotter as an element, a kind of electromagnetic vortex generating antenna array is designed, which can work in the Ku band and K band. The array antenna is modeled and its parameters are optimized with the help of high frequency structure simulator. The analysis of the simulation results indicate that electromagnetic waves generated by the array antenna can carry the orbital angular momentum when the center frequencies are chosen as 17.1 GHz and 19.7 GHz respectively. Therefore, it is concluded that the array antenna can generate dual frequency vortex electromagnetic wave.
The vortex electromagnetic wave has the characteristic of carrying orbital angular momentum. Based on this feature, vortex electromagnetic waves are used as signal carrier to achieve multi-channel signal simultaneous transmission within the same frequency band, which greatly improves the system capacity and bandwidth utilization. In this paper, by utilizing the circular microstrip antenna with a semicircular slotter as an element, a kind of electromagnetic vortex generating antenna array is designed, which can work in the Ku band and K band. The array antenna is modeled and its parameters are optimized with the help of high frequency structure simulator. The analysis of the simulation results indicate that electromagnetic waves generated by the array antenna can carry the orbital angular momentum when the center frequencies are chosen as 17.1 GHz and 19.7 GHz respectively. Therefore, it is concluded that the array antenna can generate dual frequency vortex electromagnetic wave.
2018,
30: 013208.
doi: 10.11884/HPLPB201830.170267
Abstract:
Battlefield electromagnetic environment is becoming more and more complex, which seriously affects the normal use of weapons and equipment. Active jamming is one of the most important menaces, and is the research object of this paper. According to the different characteristics of deception jamming and barrage jamming, this paper analyzes them from three aspects of time, frequency and energy, and presents the method of quantitative description of interference. It uses the energy spectrum and the formula of energy calculation to complete the characterization of barrage jamming, adopts the correlation algorithm and puts forward the concept of degree of coincidence spectrum to complete the characterization of deception jamming. The feasibility of the method is verified by Simulink/Matlab simulation. This quantitative description method is helpful for the evaluation of electromagnetic environment in battlefield.
Battlefield electromagnetic environment is becoming more and more complex, which seriously affects the normal use of weapons and equipment. Active jamming is one of the most important menaces, and is the research object of this paper. According to the different characteristics of deception jamming and barrage jamming, this paper analyzes them from three aspects of time, frequency and energy, and presents the method of quantitative description of interference. It uses the energy spectrum and the formula of energy calculation to complete the characterization of barrage jamming, adopts the correlation algorithm and puts forward the concept of degree of coincidence spectrum to complete the characterization of deception jamming. The feasibility of the method is verified by Simulink/Matlab simulation. This quantitative description method is helpful for the evaluation of electromagnetic environment in battlefield.
2018,
30: 013209.
doi: 10.11884/HPLPB201830.170286
Abstract:
The fact that switch chip in the UAV is easily damaged by the ESD electromagnetic pulse severely affects the normal communication of UAV data link. To solve the problem, this paper presents an approach by building human body-metal ESD circuit model and proceeds with a simulation analysis. It is shown that the protection effect of the chosen TVS device is significant under the 15 kV level of ESD. A comparison test of immunity to ESD electromagnetic pulse was carried out for the transceiver circuit before and after the installation of TVS protection devices respectively. The test shows that when the protection devices was installed in the circuit, the protection capacity against ESD electromagnetic pulse was maximally enhanced 7.4 times that before the installation.
The fact that switch chip in the UAV is easily damaged by the ESD electromagnetic pulse severely affects the normal communication of UAV data link. To solve the problem, this paper presents an approach by building human body-metal ESD circuit model and proceeds with a simulation analysis. It is shown that the protection effect of the chosen TVS device is significant under the 15 kV level of ESD. A comparison test of immunity to ESD electromagnetic pulse was carried out for the transceiver circuit before and after the installation of TVS protection devices respectively. The test shows that when the protection devices was installed in the circuit, the protection capacity against ESD electromagnetic pulse was maximally enhanced 7.4 times that before the installation.
2018,
30: 014001.
doi: 10.11884/HPLPB201830.170356
Abstract:
TiH alloy is a highly hydrogenated metal, which could be used as electrode of vacuum arc ion source and produces strong hydrogen ion current. TiH electrode surface has molten craters as the pure metal cathode does, and many pores form while hydrogen gas is released from the alloy. Hence TiH electrode surface has some special characteristics. This paper uses SEM to research the cathode surface appearances after single discharge and many times of discharges. The results are that the cathode spots are continuous distributions around the micro cracks, the gas pores make the surface look like cotton fiber, the numbers of cathode spots grow when the arc current grows, the spots move towards the place containing more hydrogen. These results are helpful to understand the progress of vacuum arc discharge with hydrogenated electrode, and to the applications of such morphology.
TiH alloy is a highly hydrogenated metal, which could be used as electrode of vacuum arc ion source and produces strong hydrogen ion current. TiH electrode surface has molten craters as the pure metal cathode does, and many pores form while hydrogen gas is released from the alloy. Hence TiH electrode surface has some special characteristics. This paper uses SEM to research the cathode surface appearances after single discharge and many times of discharges. The results are that the cathode spots are continuous distributions around the micro cracks, the gas pores make the surface look like cotton fiber, the numbers of cathode spots grow when the arc current grows, the spots move towards the place containing more hydrogen. These results are helpful to understand the progress of vacuum arc discharge with hydrogenated electrode, and to the applications of such morphology.
2018,
30: 014101.
doi: 10.11884/HPLPB201830.170112
Abstract:
In order to ensure the performance of the filter, reduce the volume of the filter and increase the number of chips on the wafer, a design method for the bulk acoustic wave (BAW) ladder filter is proposed. This method consists of 11 design rules and a design flow. The 11 design rules limit the shape and position of the BAW resonators (BAWRs), the distance between the BAWRs, the distance between the BAWRs and the pads and the interconnecting wire. There are 7 steps in the design flow: The first step is to preset the shape of each BAWR according to its active area value. The second step is to arrange BAWRs according to the BAW ladder filter circuit topology. The third step, "compression" layout. The fourth step, the BAWRs apodization, fine-tuning and rotation. The fifth step is to wire BAWRs and pads together. The sixth step is to detect if the layout of the filter meets the design rules. The seventh step, the use of a combined acoustic-electromagnetic BAW filter simulation method to verify the layout result. This paper presents the design rules and design flow of a 5-order BAW ladder filter with 10 series/parallel connected BAWRs. The optimized filter layout area utilization rate is 44%. Compared with the non-optimized filter layout, the optimized filter layout has lower insertion loss and higher out-of-band rejection. Thus we validate the feasibility of the layout design method.
In order to ensure the performance of the filter, reduce the volume of the filter and increase the number of chips on the wafer, a design method for the bulk acoustic wave (BAW) ladder filter is proposed. This method consists of 11 design rules and a design flow. The 11 design rules limit the shape and position of the BAW resonators (BAWRs), the distance between the BAWRs, the distance between the BAWRs and the pads and the interconnecting wire. There are 7 steps in the design flow: The first step is to preset the shape of each BAWR according to its active area value. The second step is to arrange BAWRs according to the BAW ladder filter circuit topology. The third step, "compression" layout. The fourth step, the BAWRs apodization, fine-tuning and rotation. The fifth step is to wire BAWRs and pads together. The sixth step is to detect if the layout of the filter meets the design rules. The seventh step, the use of a combined acoustic-electromagnetic BAW filter simulation method to verify the layout result. This paper presents the design rules and design flow of a 5-order BAW ladder filter with 10 series/parallel connected BAWRs. The optimized filter layout area utilization rate is 44%. Compared with the non-optimized filter layout, the optimized filter layout has lower insertion loss and higher out-of-band rejection. Thus we validate the feasibility of the layout design method.
2018,
30: 015001.
doi: 10.11884/HPLPB201830.170330
Abstract:
Based on the performance characteristics of Insulated Gate Bipolar Translator(IGBT), a new type of switch driving circuit for pulsed power system has been designed. The switch turns on quickly with this driving circuit. The principle of this driving circuit is elaborated, and the circuit based on transformer is designed to offer gate pulses voltage as high as 60 V, so that switching speed can be improved. The driving circuit and pulse forming network are simulated by software. Meanwhile, experiment confirms this strategy using pulse forming network in Blumlein construction. By this strategy of driving, both pulse current through IGBT and the current slope are improved. Extended results of the performance of driving circuit are presented, which show that, the peak current is 470.53 A and the current slope is 9.41 A/ns at the voltage of 1 kV. The target of high-speed gate driving is achieved, and the current slope is 7.53 times the data given by the datasheet.
Based on the performance characteristics of Insulated Gate Bipolar Translator(IGBT), a new type of switch driving circuit for pulsed power system has been designed. The switch turns on quickly with this driving circuit. The principle of this driving circuit is elaborated, and the circuit based on transformer is designed to offer gate pulses voltage as high as 60 V, so that switching speed can be improved. The driving circuit and pulse forming network are simulated by software. Meanwhile, experiment confirms this strategy using pulse forming network in Blumlein construction. By this strategy of driving, both pulse current through IGBT and the current slope are improved. Extended results of the performance of driving circuit are presented, which show that, the peak current is 470.53 A and the current slope is 9.41 A/ns at the voltage of 1 kV. The target of high-speed gate driving is achieved, and the current slope is 7.53 times the data given by the datasheet.
2018,
30: 015002.
doi: 10.11884/HPLPB201830.170323
Abstract:
The demagnetization current is applied to pulse transformer to improve the utilization ratio of the magnetic core. A pulse reset circuit working at low voltage was studied to generate a pulse current contrary to the main discharge current. The effectiveness of magnetic core reset under different capacitances and charging voltages was studied. The result implied that the power saved in the capacitor had a positive correlation with the effectiveness of reset circuit. Considering the output targets, a larger capacitance with a lower working voltage was selected. The output characteristics of the pulse transformer with a toroidal magnetic core emphasized the necessity of reset circuit. Experiments showed that the reset circuit could run steadily for a long time under 50 Hz repetition rate.
The demagnetization current is applied to pulse transformer to improve the utilization ratio of the magnetic core. A pulse reset circuit working at low voltage was studied to generate a pulse current contrary to the main discharge current. The effectiveness of magnetic core reset under different capacitances and charging voltages was studied. The result implied that the power saved in the capacitor had a positive correlation with the effectiveness of reset circuit. Considering the output targets, a larger capacitance with a lower working voltage was selected. The output characteristics of the pulse transformer with a toroidal magnetic core emphasized the necessity of reset circuit. Experiments showed that the reset circuit could run steadily for a long time under 50 Hz repetition rate.
2018,
30: 015101.
doi: 10.11884/HPLPB201830.170261
Abstract:
The test stand of CADS Injector Ⅰ is built at the Institute of High Energy Physics(IHEP). The 3.2 MeV, 10 mA beam from the RFQ will be transported and matched by medium energy transport line (MEBT1) to the superconductive accelerating section. To minimize the beam loss from mismatch, the Twiss parameters at the exit of RFQ should be got. The method of scanning quadrupole strength with wire scanner is used in CADS Injector Ⅰ. As to the data process, the traditional method based on matrix will bring errors for high intensity accelerators, especially at low energy when the space charge force is very strong. This paper introduces the traditional method and the new method considering space charge effect, which is based on MOGA. The result proves that the space charge should be considered when calculating the Twiss parameters for high intensity low energy accelerators.
The test stand of CADS Injector Ⅰ is built at the Institute of High Energy Physics(IHEP). The 3.2 MeV, 10 mA beam from the RFQ will be transported and matched by medium energy transport line (MEBT1) to the superconductive accelerating section. To minimize the beam loss from mismatch, the Twiss parameters at the exit of RFQ should be got. The method of scanning quadrupole strength with wire scanner is used in CADS Injector Ⅰ. As to the data process, the traditional method based on matrix will bring errors for high intensity accelerators, especially at low energy when the space charge force is very strong. This paper introduces the traditional method and the new method considering space charge effect, which is based on MOGA. The result proves that the space charge should be considered when calculating the Twiss parameters for high intensity low energy accelerators.
Coupled stochastic-deterministic method for accelerator-driven subcritical system transient analysis
2018,
30: 016001.
doi: 10.11884/HPLPB201830.170243
Abstract:
In accelerator-driven subcritical system (ADS), the transient characteristic is quite different from that of traditional critical system due to its strong external neutron source and its fuel composition for transmutation. This paper presents a coupled stochastic-deterministic method for analysing the transient characteristic of ADS. After comparing various reactor transient calculation methods, predictor-corrector improved quasi-static method was chosen to handle the time variable of neutron space-time kinetics equation. Considering the specific neutron spectrum, Monte Carlo method was used to handle the corresponding spatial, angle and energy variables. The main problem encountered is the Monte Carlo iteration instability for slightly subcritical system. Numerical results demonstrates the effectiveness of the new method.
In accelerator-driven subcritical system (ADS), the transient characteristic is quite different from that of traditional critical system due to its strong external neutron source and its fuel composition for transmutation. This paper presents a coupled stochastic-deterministic method for analysing the transient characteristic of ADS. After comparing various reactor transient calculation methods, predictor-corrector improved quasi-static method was chosen to handle the time variable of neutron space-time kinetics equation. Considering the specific neutron spectrum, Monte Carlo method was used to handle the corresponding spatial, angle and energy variables. The main problem encountered is the Monte Carlo iteration instability for slightly subcritical system. Numerical results demonstrates the effectiveness of the new method.
2018,
30: 016002.
doi: 10.11884/HPLPB201830.170219
Abstract:
Amplified Source Method(ASM) is based on point kinetics model. While used in Accelerator Driven System(ADS) with deep subcriticality and strong external source, its result is affected by the external source effect, the fundamental flux effect and the spatial effect seriously. In order to solve this problem, an annular detector positioning method with calibration has been given. In order to test the practicality of this method, further study is performed against the Kyoto University Critical Assembly by Super Monte Carlo Program for Nuclear and Radiation Simulation(SuperMC) with the HENDL database. Numerical results demonstrate that the proposed method works well for the problem and the six fission chambers in the assembly can give a good measurement result. And more detectors arranged on the fringes of the core are needed in the upcoming experiments to get more accurate measurement results.
Amplified Source Method(ASM) is based on point kinetics model. While used in Accelerator Driven System(ADS) with deep subcriticality and strong external source, its result is affected by the external source effect, the fundamental flux effect and the spatial effect seriously. In order to solve this problem, an annular detector positioning method with calibration has been given. In order to test the practicality of this method, further study is performed against the Kyoto University Critical Assembly by Super Monte Carlo Program for Nuclear and Radiation Simulation(SuperMC) with the HENDL database. Numerical results demonstrate that the proposed method works well for the problem and the six fission chambers in the assembly can give a good measurement result. And more detectors arranged on the fringes of the core are needed in the upcoming experiments to get more accurate measurement results.
2018,
30: 016003.
doi: 10.11884/HPLPB201830.170230
Abstract:
A Monte Carlo Code MCNP5 is used to analyse the energy deposition ratio and power distribution in thorium-based molten salt experiment reactor with solid fuel (TMSR-SF1). Since MCNP5 could not deal with the deposition energy from delayed beta and gamma ray photons, an analog equivalent method is used to take them into account. Then, the energy deposition rate and power distribution in TMSR-SF1 are calculated during the beginning, the middle and the end of the reactor life cycle. The results indicate that, compared with the PWR fuel rod (which is about 95%-97%), the energy deposition ratio in the pebble of TMSR-SF1 is smaller (about 93%). At the same time, TMSR-SF1 behaves good safety feature due to its low power peak factor (about 1.5).
A Monte Carlo Code MCNP5 is used to analyse the energy deposition ratio and power distribution in thorium-based molten salt experiment reactor with solid fuel (TMSR-SF1). Since MCNP5 could not deal with the deposition energy from delayed beta and gamma ray photons, an analog equivalent method is used to take them into account. Then, the energy deposition rate and power distribution in TMSR-SF1 are calculated during the beginning, the middle and the end of the reactor life cycle. The results indicate that, compared with the PWR fuel rod (which is about 95%-97%), the energy deposition ratio in the pebble of TMSR-SF1 is smaller (about 93%). At the same time, TMSR-SF1 behaves good safety feature due to its low power peak factor (about 1.5).
2018,
30: 016004.
doi: 10.11884/HPLPB201830.170250
Abstract:
This paper proposes a Shannon entropy-based strategy for adjusting history number of time-dependent transport problem automatically. By dividing the total history number of each step into many batches and simulating all batches one by one, we calculate the Shannon entropy of the survival particle distribution after each batch. If the on-the-fly diagnostic of convergence of entropy shows the survival particle distribution has converged, the calculation of the current step will be stopped in advance and the next step will be activated immediately. Test for a one-dimensional model shows this strategy has decreased the calculation time greatly while keeping the results almost unchanged simultaneously.
This paper proposes a Shannon entropy-based strategy for adjusting history number of time-dependent transport problem automatically. By dividing the total history number of each step into many batches and simulating all batches one by one, we calculate the Shannon entropy of the survival particle distribution after each batch. If the on-the-fly diagnostic of convergence of entropy shows the survival particle distribution has converged, the calculation of the current step will be stopped in advance and the next step will be activated immediately. Test for a one-dimensional model shows this strategy has decreased the calculation time greatly while keeping the results almost unchanged simultaneously.
2018,
30: 016005.
doi: 10.11884/HPLPB201830.170246
Abstract:
Prompt gamma activation imaging (PGAI) is a new type of element distribution imaging method in a non-destructive way. At present, the PGAI measure platforms which have been completed are all applied under the ideal model, and only for analyzing small pieces of sample by using the neutron source at the reactor. To discuss the accuracy and validate the feasibility of PGAI technology based on cold and thermal neutron, the ideal model of PGAI was analyzed by using Monte Carlo software. A homogeneous sample of 5 cm×5 cm×1 cm which consisted of pure iron was measured by adopting collimated neutron beam and the high-purity Ge detector, the dimension of the isovolume was 1 cm×1 cm×1 cm. It is shown that two kinds of energy neutrons all has been successfully used in PGAI. But no matter what kind of energy neutrons, when measuring the homogeneous single element sample, the consistency of image reconstruction results can't be guaranteed because of the neutron self-absorption, neutron scattering and γ-ray self-absorption. Therefore we need to analyze the physical mechanism and establish proper correction model in our later work.
Prompt gamma activation imaging (PGAI) is a new type of element distribution imaging method in a non-destructive way. At present, the PGAI measure platforms which have been completed are all applied under the ideal model, and only for analyzing small pieces of sample by using the neutron source at the reactor. To discuss the accuracy and validate the feasibility of PGAI technology based on cold and thermal neutron, the ideal model of PGAI was analyzed by using Monte Carlo software. A homogeneous sample of 5 cm×5 cm×1 cm which consisted of pure iron was measured by adopting collimated neutron beam and the high-purity Ge detector, the dimension of the isovolume was 1 cm×1 cm×1 cm. It is shown that two kinds of energy neutrons all has been successfully used in PGAI. But no matter what kind of energy neutrons, when measuring the homogeneous single element sample, the consistency of image reconstruction results can't be guaranteed because of the neutron self-absorption, neutron scattering and γ-ray self-absorption. Therefore we need to analyze the physical mechanism and establish proper correction model in our later work.
2018,
30: 016006.
doi: 10.11884/HPLPB201830.170163
Abstract:
Monte Carlo method is extensively employed in radiation shielding calculation with the advantages of high fidelity geometry modeling, complex radiation source description and continuous-energy cross sections. However, the simulation is impractical for Monte Carlo particles that have little chance of being transported to the far-source area and the statistical error may be unacceptable. Accordingly, effective global variance reduction method (GVR) is significant for Monte Carlo deep-penetration radiation shielding calculation. This work constructs weight window parameters based on forward Monte Carlo calculation to bias the particles position and energy during transport. According to the validation of shielding benchmark, particles have been guided to far-source area by using the weight window. The relative error has been decreased to less than 10%, and almost all the mesh cells have been tallied. The results show that the transport parameters obtained from forward Monte Carlo calculation could realize global variance reduction.
Monte Carlo method is extensively employed in radiation shielding calculation with the advantages of high fidelity geometry modeling, complex radiation source description and continuous-energy cross sections. However, the simulation is impractical for Monte Carlo particles that have little chance of being transported to the far-source area and the statistical error may be unacceptable. Accordingly, effective global variance reduction method (GVR) is significant for Monte Carlo deep-penetration radiation shielding calculation. This work constructs weight window parameters based on forward Monte Carlo calculation to bias the particles position and energy during transport. According to the validation of shielding benchmark, particles have been guided to far-source area by using the weight window. The relative error has been decreased to less than 10%, and almost all the mesh cells have been tallied. The results show that the transport parameters obtained from forward Monte Carlo calculation could realize global variance reduction.
2018,
30: 016007.
doi: 10.11884/HPLPB201830.170199
Abstract:
With wide application of nuclear techniques, accidents of lost radioactive sources increase. The airborne gamma spectrometer can be used for searching the lost radiation sources on the ground level. However, for radioactive sources lost in water, the use of gamma spectrometer is limited as a result of the shielding of gamma rays by water. So detection of underwater radioactive source based on Cherenkov light generated by the radioactive source is becoming important. With applications of combined simulation of Geant4 and MCNP, and continuation simulation method in Geant4, distributions and transmission of Cherenkov light generated by underwater Co-60 sealed source were simulated. The simulation reveals that wavelength of Cherenkov light is between 300~600 nm through transmission in water. The light intensity becomes stronger from the edge to the center, and the distribution range approximately equals to the depth of the radioactive source in water. The light flux is about 100 Cherenkov photons·cm-2 after 300 m transmission in water. The Cherenkov light can be detected by the characteristics of its wavelength spectrum and intensity distribution.
With wide application of nuclear techniques, accidents of lost radioactive sources increase. The airborne gamma spectrometer can be used for searching the lost radiation sources on the ground level. However, for radioactive sources lost in water, the use of gamma spectrometer is limited as a result of the shielding of gamma rays by water. So detection of underwater radioactive source based on Cherenkov light generated by the radioactive source is becoming important. With applications of combined simulation of Geant4 and MCNP, and continuation simulation method in Geant4, distributions and transmission of Cherenkov light generated by underwater Co-60 sealed source were simulated. The simulation reveals that wavelength of Cherenkov light is between 300~600 nm through transmission in water. The light intensity becomes stronger from the edge to the center, and the distribution range approximately equals to the depth of the radioactive source in water. The light flux is about 100 Cherenkov photons·cm-2 after 300 m transmission in water. The Cherenkov light can be detected by the characteristics of its wavelength spectrum and intensity distribution.
2018,
30: 016008.
doi: 10.11884/HPLPB201830.170218
Abstract:
Super Monte Carlo Program for Nuclear and Radiation Simulation (SuperMC), a general, intelligent, accurate and precise simulation software system for the design and safety evaluation of nuclear systems, is developed by FDS team of key laboratory of neutronics and radiation safety. In order to validate the accuracy of SuperMC in calculating MOX-fueled system, it was benchmarked with the VENUS-Ⅱ MOX-fueled core model released by OECD/NEA. Both cell and core calculations were performed. A series of key parameters of cell infinite multiplication factor, reaction rates per heavy isotope, core effective multiplication factor, and axial fission rate distribution of six fuel pins were calculated. The computational results are compared with measured data and the MCNP calculated results, showing that the SuperMC results agree well with the experimental results and the MCNP calculated results. The correctness and reliability of SuperMC calculating neutron transport in MOX-fuelled system are preliminarily verified.
Super Monte Carlo Program for Nuclear and Radiation Simulation (SuperMC), a general, intelligent, accurate and precise simulation software system for the design and safety evaluation of nuclear systems, is developed by FDS team of key laboratory of neutronics and radiation safety. In order to validate the accuracy of SuperMC in calculating MOX-fueled system, it was benchmarked with the VENUS-Ⅱ MOX-fueled core model released by OECD/NEA. Both cell and core calculations were performed. A series of key parameters of cell infinite multiplication factor, reaction rates per heavy isotope, core effective multiplication factor, and axial fission rate distribution of six fuel pins were calculated. The computational results are compared with measured data and the MCNP calculated results, showing that the SuperMC results agree well with the experimental results and the MCNP calculated results. The correctness and reliability of SuperMC calculating neutron transport in MOX-fuelled system are preliminarily verified.
2018,
30: 016009.
doi: 10.11884/HPLPB201830.170242
Abstract:
The solution of time dependent neutronics equations still remains a challenging problem. A weighted Monte Carlo kinetics method (wMCk) is proposed based on traditional analog Monte Carlo kinetics method (aMCk). The "implicit capture" is introduced to avoid the problem of low efficient tallies in aMCk; the definition of particle weighting leads to a more compact simulation flow due to the elimination of stack operation to particle bank. Using this method, a code named NECP-Dandi was developed in mono-energetic point-kinetics model for numerical verification and analysis. 11 test cases with different reactivity insertions were employed to verify the method. Numerical results demonstrate that wMCk is superior to aMCk in terms of accuracy, efficiency and code structure.
The solution of time dependent neutronics equations still remains a challenging problem. A weighted Monte Carlo kinetics method (wMCk) is proposed based on traditional analog Monte Carlo kinetics method (aMCk). The "implicit capture" is introduced to avoid the problem of low efficient tallies in aMCk; the definition of particle weighting leads to a more compact simulation flow due to the elimination of stack operation to particle bank. Using this method, a code named NECP-Dandi was developed in mono-energetic point-kinetics model for numerical verification and analysis. 11 test cases with different reactivity insertions were employed to verify the method. Numerical results demonstrate that wMCk is superior to aMCk in terms of accuracy, efficiency and code structure.
2018,
30: 016010.
doi: 10.11884/HPLPB201830.170252
Abstract:
Monte Carlo is a statistical method widely used in solving particle transport problems. A Monte Carlo code has the advantages of much flexible geometry and high fidelity. Taking advantage of this, reactor core analysis can be solved with high fidelity, although much computing cost is needed. With the feedback of a thermal hydraulic code, the core in hot full power condition on steady state can be computed by a Monte Carlo code. In this paper, JMCT, a Monte Carlo code, and COBRA-EN, a subchannel code, are coupled through the method of internal coupling. Picard iteration is used between neutron transport calculation and thermal-hydraulic calculation. The HFP steady-state calculation in a mini-core benchmark in NURISP project is used to validate the coupling code. The result agrees with that of SERPENT2/SUBCHANFLOW and TRIPOLI/SUBCHANFLOW, verifying the accuracy of this code.
Monte Carlo is a statistical method widely used in solving particle transport problems. A Monte Carlo code has the advantages of much flexible geometry and high fidelity. Taking advantage of this, reactor core analysis can be solved with high fidelity, although much computing cost is needed. With the feedback of a thermal hydraulic code, the core in hot full power condition on steady state can be computed by a Monte Carlo code. In this paper, JMCT, a Monte Carlo code, and COBRA-EN, a subchannel code, are coupled through the method of internal coupling. Picard iteration is used between neutron transport calculation and thermal-hydraulic calculation. The HFP steady-state calculation in a mini-core benchmark in NURISP project is used to validate the coupling code. The result agrees with that of SERPENT2/SUBCHANFLOW and TRIPOLI/SUBCHANFLOW, verifying the accuracy of this code.
2018,
30: 019001.
doi: 10.11884/HPLPB201830.170180
Abstract:
The flammable liquid detection, especially the emote flammable liquid dynamic monitoring, is of great importance to public security, customs and civil aviation. Hence, a near infrared (NIR) multi-spectral imaging system based on liquid crystal tunable filter was developed. To increase the speed of scanning imaging and data processing, the number of spectral channel was reduced remarkably by band selection method. The experiment of flammable liquid detection by the system was carried out in different environments, and the result show that the detection accuracy of the system is 100% when the object was motionless, and it is more than 95% when the movement speed of object was less than 0.2 m/s.
The flammable liquid detection, especially the emote flammable liquid dynamic monitoring, is of great importance to public security, customs and civil aviation. Hence, a near infrared (NIR) multi-spectral imaging system based on liquid crystal tunable filter was developed. To increase the speed of scanning imaging and data processing, the number of spectral channel was reduced remarkably by band selection method. The experiment of flammable liquid detection by the system was carried out in different environments, and the result show that the detection accuracy of the system is 100% when the object was motionless, and it is more than 95% when the movement speed of object was less than 0.2 m/s.
2018,
30: 010000.
