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RSS2019 Vol. 31, No. 2
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2019,
31: 020101.
doi: 10.11884/HPLPB201931.190025
Abstract:
A 780 nm continuous-wave, which is output by extra-cavity semiconductor laser with a bulk bragg grating, is used as the fundamental input light source of the Second Harmonic Generation (SHG) system. Line width of the fundamental light is 0.13 nm. Based on the type Ⅰ phase-matching and Lithium Triborate (LBO) crystal, 390 nm second harmonic is obtained. The emitted average output power is 30 μW (SHG efficiency is 0.01%). We provide a new technical route for the achievement of high-power UV beams.
A 780 nm continuous-wave, which is output by extra-cavity semiconductor laser with a bulk bragg grating, is used as the fundamental input light source of the Second Harmonic Generation (SHG) system. Line width of the fundamental light is 0.13 nm. Based on the type Ⅰ phase-matching and Lithium Triborate (LBO) crystal, 390 nm second harmonic is obtained. The emitted average output power is 30 μW (SHG efficiency is 0.01%). We provide a new technical route for the achievement of high-power UV beams.
2019,
31: 020201.
doi: 10.11884/HPLPB201931.180254
Abstract:
The international quasi-monoenergetic neutron sources for the single event effect (SEE) study are investigated, the related issues including the 7Li(p, n)7Be nuclear reaction, the facility layout, and the theoretical calculations and experimental measurements of the neutron field parameters such as the neutron flux, the neutron energy spectrum, the neutron beam profile and its uniformity, and the thermal neutron background, are systematically introduced. The quasi-monoenergetic neutron SEE experiments require that the neutron source have a high neutron flux, large and uniform beam spot, and low thermal neutron background, and that an accurate neutron energy spectrum be obtained through experiments. The quasi-monoenergetic neutron SEE experiments and three methods for the tail correction of neutron SEE cross sections are introduced.
The international quasi-monoenergetic neutron sources for the single event effect (SEE) study are investigated, the related issues including the 7Li(p, n)7Be nuclear reaction, the facility layout, and the theoretical calculations and experimental measurements of the neutron field parameters such as the neutron flux, the neutron energy spectrum, the neutron beam profile and its uniformity, and the thermal neutron background, are systematically introduced. The quasi-monoenergetic neutron SEE experiments require that the neutron source have a high neutron flux, large and uniform beam spot, and low thermal neutron background, and that an accurate neutron energy spectrum be obtained through experiments. The quasi-monoenergetic neutron SEE experiments and three methods for the tail correction of neutron SEE cross sections are introduced.
2019,
31: 021001.
doi: 10.11884/HPLPB201931.180331
Abstract:
The synchronous lighting source of high-speed photography is a kind of high brightness flash light source which uses the pulsed xenon lamp as the output load. Its driving circuit adopts pulse forming network PFN circuit, using Orcad Pspice software to simulate the discharge current of FFN, its simulation result has certain guiding significance. The power supply has the function of manual trigger and synchronous trigger, the front and back edges of the output pulse have good time response. The charge voltage of xenon lamp is 0~3.5 kV, and the delay time of trigger signal and optical waveform is 125 μs with light wave shape. The design principle and technical scheme of the power supply are proved by the experiment.
The synchronous lighting source of high-speed photography is a kind of high brightness flash light source which uses the pulsed xenon lamp as the output load. Its driving circuit adopts pulse forming network PFN circuit, using Orcad Pspice software to simulate the discharge current of FFN, its simulation result has certain guiding significance. The power supply has the function of manual trigger and synchronous trigger, the front and back edges of the output pulse have good time response. The charge voltage of xenon lamp is 0~3.5 kV, and the delay time of trigger signal and optical waveform is 125 μs with light wave shape. The design principle and technical scheme of the power supply are proved by the experiment.
2019,
31: 021002.
doi: 10.11884/HPLPB201931.180335
Abstract:
The power output stability of semiconductor laser in the laser system is closely related to the working temperature. As the control precision is not high and control speed of temperature control system is slow in the laser system, this paper discusses a new temperature stabilization system. This system gets laser temperature by PT-100 temperature sensor, and uses the least squares fitting to process the temperature data, thus to ensure the temperature measurement accuracy of 0.01 ℃. And the system adjusts the temperature by PID controller whose parameter is optimized by particle swarm optimization algorithm. Simulation experiments and actual test show that of the temperature system can quickly stabilize the temperature of laser, the time of adjustment is less than 11 s. And the fluctuations of temperature is about ±0.02 ℃ after the system reaching the steady state. Compared with the traditional temperature control method, the system can achieve self-tuning of parameters and automatically adjust the temperature, the laser temperature in the high-power laser system has a good stability.
The power output stability of semiconductor laser in the laser system is closely related to the working temperature. As the control precision is not high and control speed of temperature control system is slow in the laser system, this paper discusses a new temperature stabilization system. This system gets laser temperature by PT-100 temperature sensor, and uses the least squares fitting to process the temperature data, thus to ensure the temperature measurement accuracy of 0.01 ℃. And the system adjusts the temperature by PID controller whose parameter is optimized by particle swarm optimization algorithm. Simulation experiments and actual test show that of the temperature system can quickly stabilize the temperature of laser, the time of adjustment is less than 11 s. And the fluctuations of temperature is about ±0.02 ℃ after the system reaching the steady state. Compared with the traditional temperature control method, the system can achieve self-tuning of parameters and automatically adjust the temperature, the laser temperature in the high-power laser system has a good stability.
2019,
31: 022001.
doi: 10.11884/HPLPB201931.180340
Abstract:
Magnetorheological finishing of first-order discontinuous optical elements is one of the difficult problems that restrict the development of high-precision and high-efficiency optical manufacturing in China. In this paper, a fluid dynamics analysis method for magnetorheological finishing concerning the first order discontinuous optical elements is presented. Firstly, reasonable assumptions are made for the flow field under the practical condition of magnetorheological finishing. Secondly, based on the micro-element hydrodynamic equation, a flow field analysis method suitable for the first order discontinuous surface shape is established. Finally, a numerical calculation method for the flow field governing equation is established based on the finite difference method and numerical iteration method. Through numerical simulation for cutting distance ranging over 1~18 mm, it is found that the pressure distribution pattern of the first-order discontinuous surface obtained by the proposed method is correct, and the discontinuous pressure drop generated by the proposed method is consistent with that of the experimental observation.
Magnetorheological finishing of first-order discontinuous optical elements is one of the difficult problems that restrict the development of high-precision and high-efficiency optical manufacturing in China. In this paper, a fluid dynamics analysis method for magnetorheological finishing concerning the first order discontinuous optical elements is presented. Firstly, reasonable assumptions are made for the flow field under the practical condition of magnetorheological finishing. Secondly, based on the micro-element hydrodynamic equation, a flow field analysis method suitable for the first order discontinuous surface shape is established. Finally, a numerical calculation method for the flow field governing equation is established based on the finite difference method and numerical iteration method. Through numerical simulation for cutting distance ranging over 1~18 mm, it is found that the pressure distribution pattern of the first-order discontinuous surface obtained by the proposed method is correct, and the discontinuous pressure drop generated by the proposed method is consistent with that of the experimental observation.
2019,
31: 022002.
doi: 10.11884/HPLPB201931.180325
Abstract:
In order to investigate the problem of mode transition of radio frequency Ar inductively coupled plasma under the influence of axial magnetic field, a small inductively coupled plasma generator experimental system was designed and built. The impedance analysis method was used in the experiment, also verified correct by Langmuir probe method. It is found out that, when the pressure is 10 Pa, the increase of axial magnetic field intensity will increase the discharge power of E-H and H-E mode transitions. At the same time, the stronger the magnetic field is, the lower the electron density at the center of discharge area is. According to some preliminary analysis, charged particles make cyclotron motion at the influence of Lorentz force, which leads to the reduced collisions of high-energy electrons in the direction perpendicular to the magnetic field. Accordingly, electron density decreases and power coupling efficiency decreases. Further analysis on electron energy probability function (EEPF) has suggested that axial magnetic field has stronger restriction on electronic motion under E mode than H mode. As a result, the reduced collisions lead to a higher high-energy (>27 eV) proportion and a more uniform electron energy probability function under E mode, which has conformed with aforementioned analysis.
In order to investigate the problem of mode transition of radio frequency Ar inductively coupled plasma under the influence of axial magnetic field, a small inductively coupled plasma generator experimental system was designed and built. The impedance analysis method was used in the experiment, also verified correct by Langmuir probe method. It is found out that, when the pressure is 10 Pa, the increase of axial magnetic field intensity will increase the discharge power of E-H and H-E mode transitions. At the same time, the stronger the magnetic field is, the lower the electron density at the center of discharge area is. According to some preliminary analysis, charged particles make cyclotron motion at the influence of Lorentz force, which leads to the reduced collisions of high-energy electrons in the direction perpendicular to the magnetic field. Accordingly, electron density decreases and power coupling efficiency decreases. Further analysis on electron energy probability function (EEPF) has suggested that axial magnetic field has stronger restriction on electronic motion under E mode than H mode. As a result, the reduced collisions lead to a higher high-energy (>27 eV) proportion and a more uniform electron energy probability function under E mode, which has conformed with aforementioned analysis.
2019,
31: 022003.
doi: 10.11884/HPLPB201931.180206
Abstract:
Artificial neural network(NN) as a powerful nonlinear data processing method, has been successfully applied to process electron temperature for Thomson scattering system on HL-2A. A type of perception is chosen. The NN has three layers: input layer, hidden layer, and output layer. Calibration data or measured data are the input layer, hidden layer uses sigmoid function as transfer function, and output layer is electron temperature. The calculation results fit well with that results calculated by traditional minimization chi-square method. And its calculation speed, about 1 ms per shot and per spatial point, is about 20 times faster than the minimization chi-square method. Therefore, it is possible for real time feed-back control plasma discharge by electron temperature measured by Thomson scattering on HL-2M, ITER or CFTER.
Artificial neural network(NN) as a powerful nonlinear data processing method, has been successfully applied to process electron temperature for Thomson scattering system on HL-2A. A type of perception is chosen. The NN has three layers: input layer, hidden layer, and output layer. Calibration data or measured data are the input layer, hidden layer uses sigmoid function as transfer function, and output layer is electron temperature. The calculation results fit well with that results calculated by traditional minimization chi-square method. And its calculation speed, about 1 ms per shot and per spatial point, is about 20 times faster than the minimization chi-square method. Therefore, it is possible for real time feed-back control plasma discharge by electron temperature measured by Thomson scattering on HL-2M, ITER or CFTER.
2019,
31: 023001.
doi: 10.11884/HPLPB201931.180365
Abstract:
Based on the interference tolerance of UAV GPS receiver, this paper analyzes the mechanism of GPS ultra-wide spectrum strong electromagnetic pulse effect. It presents the effect test of high-repetition ultra-wide spectrum electromagnetic pulse jammer on typical micro-UAV and analyses high-repetition and ultra-wide spectrum electromagnetic pulse interference effects of UAV GPS receivers in different positions, different heights, different states, and different flight modes. The test results show that the high-frequency ultra-wide-spectrum electromagnetic pulse has different degrees of interference on the GPS, the image transmission system and the lower-view sensor of the UAV, and the interference can be within a certain range by interfering with the GPS receiver of the UAV. The interference can cause drone's failure to take off normally, even make the UAV out of control during the flight process. It is verified that the high-repetition ultra-wide spectrum electromagnetic pulse will cause interference to the GPS receiver, making the GPS unable to work.
Based on the interference tolerance of UAV GPS receiver, this paper analyzes the mechanism of GPS ultra-wide spectrum strong electromagnetic pulse effect. It presents the effect test of high-repetition ultra-wide spectrum electromagnetic pulse jammer on typical micro-UAV and analyses high-repetition and ultra-wide spectrum electromagnetic pulse interference effects of UAV GPS receivers in different positions, different heights, different states, and different flight modes. The test results show that the high-frequency ultra-wide-spectrum electromagnetic pulse has different degrees of interference on the GPS, the image transmission system and the lower-view sensor of the UAV, and the interference can be within a certain range by interfering with the GPS receiver of the UAV. The interference can cause drone's failure to take off normally, even make the UAV out of control during the flight process. It is verified that the high-repetition ultra-wide spectrum electromagnetic pulse will cause interference to the GPS receiver, making the GPS unable to work.
2019,
31: 023002.
doi: 10.11884/HPLPB201931.180292
Abstract:
The conventional high power microwave (HPM) radiation measurement system often consists of antennas, attenuators, detectors and other components. There will always be parametric selection dilemma when the conventional system is used in HPM beat-wave radiation measurement, because the system is designed and tested on single frequency while beat-wave signal is composed of many frequency components. Furthermore, the utilization of detectors in beat-wave radiation measurement will lead to new beat-wave frequency components due to their nonlinear feature. It is commonly difficult to measure the output waveform accurately when the signal is superimposed with the new beat-wave frequency components. To solve these problems, a new measurement method based on frequency separation and electric field backstepping is proposed. The application of the proposed method is able to effectively reduce uncertainty of beat-wave radiation measurement to less than 0.3 dB, which satisfies the requirement of accurate HPM beat-wave radiation measurement.
The conventional high power microwave (HPM) radiation measurement system often consists of antennas, attenuators, detectors and other components. There will always be parametric selection dilemma when the conventional system is used in HPM beat-wave radiation measurement, because the system is designed and tested on single frequency while beat-wave signal is composed of many frequency components. Furthermore, the utilization of detectors in beat-wave radiation measurement will lead to new beat-wave frequency components due to their nonlinear feature. It is commonly difficult to measure the output waveform accurately when the signal is superimposed with the new beat-wave frequency components. To solve these problems, a new measurement method based on frequency separation and electric field backstepping is proposed. The application of the proposed method is able to effectively reduce uncertainty of beat-wave radiation measurement to less than 0.3 dB, which satisfies the requirement of accurate HPM beat-wave radiation measurement.
2019,
31: 023201.
doi: 10.11884/HPLPB201931.180338
Abstract:
The standard texts (Recommendations, Manuals, Reports, etc.) in ITU-R SG3 related to the interference and compatibility analysis are systematically organized and analyzed in this contribution. The main propagation mechanisms leading to radio signal interference are introduced. The propagation models of interference and compatibility analysis are also briefly introduced. In particular, the latest developments of related propagation models and standards are also given in this paper, while the development of standards and models is proposed in the conclusion.
The standard texts (Recommendations, Manuals, Reports, etc.) in ITU-R SG3 related to the interference and compatibility analysis are systematically organized and analyzed in this contribution. The main propagation mechanisms leading to radio signal interference are introduced. The propagation models of interference and compatibility analysis are also briefly introduced. In particular, the latest developments of related propagation models and standards are also given in this paper, while the development of standards and models is proposed in the conclusion.
2019,
31: 023202.
doi: 10.11884/HPLPB201931.180322
Abstract:
Due to the problem of behavior failure or functional safety for electronic system caused by electromagnetic interference (EMI), the electromagnetic susceptibility characteristics of programmable integrated circuit (IC) based on the conducted coupling of power supply network are studied. The topology structure of power supply network and the EMI conducted coupling mechanism of typical FPGA are analyzed, and the immunity test platform based on EMI direct power injection method is designed. The electromagnetic susceptibility feature of typical functional units are measured when the EMI is conducted to the power supply network of the IC under test, then the susceptibility thresholds of internal phase-locked loop (PLL) circuit, logic element (LE) and input/output port is obtained and the influence law of LE redundancy design on EMS characteristic of corresponding circuits is given. The results show that, for interference frequencies in the range of 10 MHz-1 GHz, functional units with EMI susceptibility from high to low are PLL, LE and IO, and the EMI susceptibility of IC ground network is 2-7 dBmW higher. LE redundancy design can effectively improve the EMS of logical functional units.
Due to the problem of behavior failure or functional safety for electronic system caused by electromagnetic interference (EMI), the electromagnetic susceptibility characteristics of programmable integrated circuit (IC) based on the conducted coupling of power supply network are studied. The topology structure of power supply network and the EMI conducted coupling mechanism of typical FPGA are analyzed, and the immunity test platform based on EMI direct power injection method is designed. The electromagnetic susceptibility feature of typical functional units are measured when the EMI is conducted to the power supply network of the IC under test, then the susceptibility thresholds of internal phase-locked loop (PLL) circuit, logic element (LE) and input/output port is obtained and the influence law of LE redundancy design on EMS characteristic of corresponding circuits is given. The results show that, for interference frequencies in the range of 10 MHz-1 GHz, functional units with EMI susceptibility from high to low are PLL, LE and IO, and the EMI susceptibility of IC ground network is 2-7 dBmW higher. LE redundancy design can effectively improve the EMS of logical functional units.
2019,
31: 024101.
doi: 10.11884/HPLPB201931.180374
Abstract:
With the development of channel down-scaling of low-voltage low-power CMOS technology, the optimal operation points are shown to shift from the strong inversion toward lower moderated inversion and weak inversion regimes. High-frequency equivalent circuit modeling is a prerequisite for finding the physical mechanism of MOSFET device, and is essential for the HF integrated circuits. Based on the physical structure of 45 nm MOSFET device and its Y parameters analysis, a quasi-static approximate RF equivalent circuit model and its high-precision simplified parameter extraction algorithm is proposed by taking into account the intrinsic physical characteristics of the device, the electromagnetic characteristics of the pin and the parasitic characteristics of the test pad and test interconnects, which are used to describe the bias dependence from the strong inversion and weak inversion regimes. Therefore, the device characterizations offer excellent accuracy, continuity and smoothness under different bias condition, and can be easily implanted into commercial EDA tools. Direct extraction method is performed by S-parameter analysis including the intrinsic and the extrinsic components and the substrate-related effect. Finally, the practicability and the accuracy of the proposed model and its parameters extract algorithm are verified by the consistency comparison of the simulated results by using ADS2013 tool and the measured S parameters. The experimental results show the bias dependence of 45nm MOSFET.
With the development of channel down-scaling of low-voltage low-power CMOS technology, the optimal operation points are shown to shift from the strong inversion toward lower moderated inversion and weak inversion regimes. High-frequency equivalent circuit modeling is a prerequisite for finding the physical mechanism of MOSFET device, and is essential for the HF integrated circuits. Based on the physical structure of 45 nm MOSFET device and its Y parameters analysis, a quasi-static approximate RF equivalent circuit model and its high-precision simplified parameter extraction algorithm is proposed by taking into account the intrinsic physical characteristics of the device, the electromagnetic characteristics of the pin and the parasitic characteristics of the test pad and test interconnects, which are used to describe the bias dependence from the strong inversion and weak inversion regimes. Therefore, the device characterizations offer excellent accuracy, continuity and smoothness under different bias condition, and can be easily implanted into commercial EDA tools. Direct extraction method is performed by S-parameter analysis including the intrinsic and the extrinsic components and the substrate-related effect. Finally, the practicability and the accuracy of the proposed model and its parameters extract algorithm are verified by the consistency comparison of the simulated results by using ADS2013 tool and the measured S parameters. The experimental results show the bias dependence of 45nm MOSFET.
2019,
31: 025001.
doi: 10.11884/HPLPB201931.180279
Abstract:
This paper introduces a topology structure of Buck-Boost converter based on AC-Link series resonant. The state-plane analysis method is used to analyze the working process of series resonant circuit in Buck mode and Boost mode. This method is relatively direct, accurate and simple compared with the simple basic wave equal effect analysis method. A detailed derivation is given and a control algorithm is proposed. The simulation model of Matlab/Simulink is set up. The simulation results show that the control algorithm can realize the function of Buck and Boost, and low current harmonic content. And the converter can adjust the output voltage in a wide range.
This paper introduces a topology structure of Buck-Boost converter based on AC-Link series resonant. The state-plane analysis method is used to analyze the working process of series resonant circuit in Buck mode and Boost mode. This method is relatively direct, accurate and simple compared with the simple basic wave equal effect analysis method. A detailed derivation is given and a control algorithm is proposed. The simulation model of Matlab/Simulink is set up. The simulation results show that the control algorithm can realize the function of Buck and Boost, and low current harmonic content. And the converter can adjust the output voltage in a wide range.
2019,
31: 025002.
doi: 10.11884/HPLPB201931.180242
Abstract:
This paper introduces a single-shot compact pulsed power source (PPS) based on an explosively driven flux compression generator (FCG) for some off-grid applications. The PPS was designed to rapidly charge a capacitive load of 65 pF to hundreds of kilo volts. Considering the impedance mismatch between the FCG and the load, a power conditioning module mainly consisting of an intermediate capacitor, an electro-explosive opening switch (EEOS) and an air-cored transformer was employed. This paper presents the design and experimental results in detail. Besides, it analyzes the experimental results and discusses the possible improvements in future. It is indicated that the capacitive load was successfully charged to -352 kV with a rising time of about 10 ns.
This paper introduces a single-shot compact pulsed power source (PPS) based on an explosively driven flux compression generator (FCG) for some off-grid applications. The PPS was designed to rapidly charge a capacitive load of 65 pF to hundreds of kilo volts. Considering the impedance mismatch between the FCG and the load, a power conditioning module mainly consisting of an intermediate capacitor, an electro-explosive opening switch (EEOS) and an air-cored transformer was employed. This paper presents the design and experimental results in detail. Besides, it analyzes the experimental results and discusses the possible improvements in future. It is indicated that the capacitive load was successfully charged to -352 kV with a rising time of about 10 ns.
2019,
31: 025101.
doi: 10.11884/HPLPB201931.180276
Abstract:
In the RF system of the accelerator, when the reflected power back to the klystron in the current RF pulse exceeds certain threshold, the system should send out an alarm signal before the next RF pulse arrives, and then cut off the trigger signal. By this way, the klystron ceramic window can be protected by reducing the damage caused by the high-power RF reflection; the online lifetime of the klystron can be prolonged. Three cost-effective and easy-to-implement solutions have been introduced: the mask alarm scheme by using the PicoScope virtual oscilloscope, the chip-made reflective protection plug-in based on the RF detection and alarm output functions, and the upgrade of the original RF power meter. The "3+1" reflection protection response time test method was innovatively proposed, it was used to thoroughly test the above three schemes. Finally, better results were obtained by using the latter two schemes. After comprehensive consideration, the upgraded RF power meter was used in the final implementation plan. At present, the upgraded RF power meter has been operating online stably and reliably for more than one year.
In the RF system of the accelerator, when the reflected power back to the klystron in the current RF pulse exceeds certain threshold, the system should send out an alarm signal before the next RF pulse arrives, and then cut off the trigger signal. By this way, the klystron ceramic window can be protected by reducing the damage caused by the high-power RF reflection; the online lifetime of the klystron can be prolonged. Three cost-effective and easy-to-implement solutions have been introduced: the mask alarm scheme by using the PicoScope virtual oscilloscope, the chip-made reflective protection plug-in based on the RF detection and alarm output functions, and the upgrade of the original RF power meter. The "3+1" reflection protection response time test method was innovatively proposed, it was used to thoroughly test the above three schemes. Finally, better results were obtained by using the latter two schemes. After comprehensive consideration, the upgraded RF power meter was used in the final implementation plan. At present, the upgraded RF power meter has been operating online stably and reliably for more than one year.
2019,
31: 025102.
doi: 10.11884/HPLPB201931.019003
Abstract:
Power supply monitoring system provides important real-time data for machine research, auto beam adjustment and deep learning on HIRFL (Heavy Ion Research Facility Lanzhou). During the EPICS upgrade of HIRFL, the power supply monitoring system was redesigned and a distributed structure was adopted to form an extended layout of the upper layer/middleware and the bottom layer. The middleware processes the upper layer data and sends data to the lower layer, avoiding invalid parameters applied to the lower devices and simplifying the handling of exception. To facilitate beam adjustment, the display interface is integrate, displaying large amounts of data on different OPI is optimized and the display is improved. In order to carry on the off-line analysis of the data, a NoSQL database cluster was built to realize multiple copies of high priority data and to store multi-node real-time data, also to improve data security and database read/write speed, in addition to avoid designing complicated table structure and to expand database cluster optimization and nodes increasing.
Power supply monitoring system provides important real-time data for machine research, auto beam adjustment and deep learning on HIRFL (Heavy Ion Research Facility Lanzhou). During the EPICS upgrade of HIRFL, the power supply monitoring system was redesigned and a distributed structure was adopted to form an extended layout of the upper layer/middleware and the bottom layer. The middleware processes the upper layer data and sends data to the lower layer, avoiding invalid parameters applied to the lower devices and simplifying the handling of exception. To facilitate beam adjustment, the display interface is integrate, displaying large amounts of data on different OPI is optimized and the display is improved. In order to carry on the off-line analysis of the data, a NoSQL database cluster was built to realize multiple copies of high priority data and to store multi-node real-time data, also to improve data security and database read/write speed, in addition to avoid designing complicated table structure and to expand database cluster optimization and nodes increasing.
2019,
31: 026001.
doi: 10.11884/HPLPB201931.180222
Abstract:
Aluminum alloy, as a kind of important structural materials used in laser-driven Inertial Confinement Fusion (ICF) facilities, will be exposed to high-energy neutrons with high yields. The activation level of aluminum alloys should be taken into account when selecting the materials used in ICF facilities during design. Specific activities and dose rates for three different aluminum alloys after irradiation by 14 MeV neutrons were calculated and compared using the FISPACT inventory code. The results show that both specific activity and dose rate decrease 3 magnitudes in one week after irradiation. It is found that aluminum contributes to more than 90% of the total activity (dose rate) in the first week while Manganese and zinc in aluminum alloys are dominant in longer cooling times. The main residual nuclides are 24Na, 54Mn and 65Zn.For safety considerations, it is better to choose aluminum alloys with lower Mn and Zn contents.
Aluminum alloy, as a kind of important structural materials used in laser-driven Inertial Confinement Fusion (ICF) facilities, will be exposed to high-energy neutrons with high yields. The activation level of aluminum alloys should be taken into account when selecting the materials used in ICF facilities during design. Specific activities and dose rates for three different aluminum alloys after irradiation by 14 MeV neutrons were calculated and compared using the FISPACT inventory code. The results show that both specific activity and dose rate decrease 3 magnitudes in one week after irradiation. It is found that aluminum contributes to more than 90% of the total activity (dose rate) in the first week while Manganese and zinc in aluminum alloys are dominant in longer cooling times. The main residual nuclides are 24Na, 54Mn and 65Zn.For safety considerations, it is better to choose aluminum alloys with lower Mn and Zn contents.
2019,
31: 026002.
doi: 10.11884/HPLPB201931.180377
Abstract:
The real-time algorithm of correlation calculation is presented for neutron pulse series up to 1 GHz sampling rates based on PC. The method is proposed based on the special structure of the series. Simulation demonstrates that the calculation time of the proposed correlation function algorithm is less than 1 h, the algorithm meets the demand of real-time correlation calculation, which make it possible to detect the quality and abundance of uranium components in real time.
The real-time algorithm of correlation calculation is presented for neutron pulse series up to 1 GHz sampling rates based on PC. The method is proposed based on the special structure of the series. Simulation demonstrates that the calculation time of the proposed correlation function algorithm is less than 1 h, the algorithm meets the demand of real-time correlation calculation, which make it possible to detect the quality and abundance of uranium components in real time.
2019,
31: 020000.
