Email alert
RSS2019 Vol. 31, No. 9
Display Method:
2019,
31: 090000.
2019,
31: 091001.
doi: 10.11884/HPLPB201931.190012
Abstract:
For the problem of precision deficiency of the analysis model caused by nonlinear factors of the joint parts in the ϕ150 mm mirror, the equivalent linearized model and the model updating method were presented. First, the experimental modal parameters of the ϕ150 mm mirror within 800 Hz were tested and obtained under the actual assembly and boundary conditions. Then, according to the dynamic characteristics of the interface joints, the equivalent finite element model of the mirror was classified as the connection model of fixed parts, the screw model and the equivalent gap model of the clamping parts, which were modeled by beam elements, rigid elements and spring elements. Finally, taking the measured experimental data including natural frequencies and modal shapes as the objective function, the dynamic model of the ϕ150 mm mirror was corrected by using optimization method. At the same time, the modified model was divided into two parts according to the characteristics of the joints by adopting the idea of hierarchical and step-by-step modification to improve the efficiency of the correction process. The results indicate that the average error of natural frequencies within 800 Hz after model updating is 1.6%, and the minimum value of modal assurance criterion is greater than 0.8, which improves the accuracy of the dynamic model for the reflective mirror. And the equivalent linearized model is also verified.
For the problem of precision deficiency of the analysis model caused by nonlinear factors of the joint parts in the ϕ150 mm mirror, the equivalent linearized model and the model updating method were presented. First, the experimental modal parameters of the ϕ150 mm mirror within 800 Hz were tested and obtained under the actual assembly and boundary conditions. Then, according to the dynamic characteristics of the interface joints, the equivalent finite element model of the mirror was classified as the connection model of fixed parts, the screw model and the equivalent gap model of the clamping parts, which were modeled by beam elements, rigid elements and spring elements. Finally, taking the measured experimental data including natural frequencies and modal shapes as the objective function, the dynamic model of the ϕ150 mm mirror was corrected by using optimization method. At the same time, the modified model was divided into two parts according to the characteristics of the joints by adopting the idea of hierarchical and step-by-step modification to improve the efficiency of the correction process. The results indicate that the average error of natural frequencies within 800 Hz after model updating is 1.6%, and the minimum value of modal assurance criterion is greater than 0.8, which improves the accuracy of the dynamic model for the reflective mirror. And the equivalent linearized model is also verified.
2019,
31: 091002.
doi: 10.11884/HPLPB201931.190019
Abstract:
A high-power LED uniform light source with one large-size near-focus aspherical lens is designed based on the principles of geometric optics and non-imaging optics. First of all, the parameters of the aspherical lens are obtained according to the geometric optics theory. Then, the aspherical lens is optimized in ZEMAX according to the evaluation function to focal length of 76.79 mm and diameter of 200 mm. The aspherical lens is further imported into the software TracePro for ray tracing simulation. According to the simulated results, the aspherical lens is machined for the next experiment. The experimental results indicate that the uniform light source can reach the target with a divergence angle of ±8.53° at 60 cm and uniformity of 95.82%.
A high-power LED uniform light source with one large-size near-focus aspherical lens is designed based on the principles of geometric optics and non-imaging optics. First of all, the parameters of the aspherical lens are obtained according to the geometric optics theory. Then, the aspherical lens is optimized in ZEMAX according to the evaluation function to focal length of 76.79 mm and diameter of 200 mm. The aspherical lens is further imported into the software TracePro for ray tracing simulation. According to the simulated results, the aspherical lens is machined for the next experiment. The experimental results indicate that the uniform light source can reach the target with a divergence angle of ±8.53° at 60 cm and uniformity of 95.82%.
2019,
31: 091003.
doi: 10.11884/HPLPB201931.190046
Abstract:
Laue crystal monochromator are commonly used to monochromate high-energy X-rays (above 50 keV). Through bending the thin crystal, focused monochromatic beams could be obtained. However, twisted deformation would inevitably occur during bending crystal, which seriously affects monochromator efficiency. In this paper, wave optics simulation method was applied to study the influence of the bent crystal twisted on the performance of the Laue crystal monochromator. Moreover, in order to eliminate the crystal twist, a rotary mechanism of rotation angle fine adjustment was designed. The rotary mechanism includes a series of flexure hinges arranged symmetrically. Furthermore, the dynamics performances of the mechanism were also analyzed by using finite element method. The results show that when the rotation angle was within ±2°, the maximum shift of rotation center was less than 20 μm, the angular resolution achieved less than 1″ and dynamic range was up to 104, which totally meet the design requirements.
Laue crystal monochromator are commonly used to monochromate high-energy X-rays (above 50 keV). Through bending the thin crystal, focused monochromatic beams could be obtained. However, twisted deformation would inevitably occur during bending crystal, which seriously affects monochromator efficiency. In this paper, wave optics simulation method was applied to study the influence of the bent crystal twisted on the performance of the Laue crystal monochromator. Moreover, in order to eliminate the crystal twist, a rotary mechanism of rotation angle fine adjustment was designed. The rotary mechanism includes a series of flexure hinges arranged symmetrically. Furthermore, the dynamics performances of the mechanism were also analyzed by using finite element method. The results show that when the rotation angle was within ±2°, the maximum shift of rotation center was less than 20 μm, the angular resolution achieved less than 1″ and dynamic range was up to 104, which totally meet the design requirements.
2019,
31: 091004.
doi: 10.11884/HPLPB201931.190164
Abstract:
This paper researches on laser damage characteristics of Ⅱ-type DKDP crystals used for nonlinear frequency conversion of third harmonic under 355 nm laser with 35 ps, 850 ps and 7.6 ns pulse duration. The damage threshold, probability and the damage pinpoints morphology, density, size under different pulse duration are compared and analyzed. The results show that the laser energy absorption of the precursors is linearly related to the pulse duration. Under 35 ps laser, one type of precursors absorbs laser energy, which results in melting damage pinpoints. Under 850 ps laser, two types of precursors absorb laser energy and generate mechanical response form damaged pinpoints made of melting center point and surrounded by cracks. Under 7.6 ns laser, only one type of precursors takes effect and shares the same pinpoints characteristics with 850 ps laser.
This paper researches on laser damage characteristics of Ⅱ-type DKDP crystals used for nonlinear frequency conversion of third harmonic under 355 nm laser with 35 ps, 850 ps and 7.6 ns pulse duration. The damage threshold, probability and the damage pinpoints morphology, density, size under different pulse duration are compared and analyzed. The results show that the laser energy absorption of the precursors is linearly related to the pulse duration. Under 35 ps laser, one type of precursors absorbs laser energy, which results in melting damage pinpoints. Under 850 ps laser, two types of precursors absorb laser energy and generate mechanical response form damaged pinpoints made of melting center point and surrounded by cracks. Under 7.6 ns laser, only one type of precursors takes effect and shares the same pinpoints characteristics with 850 ps laser.
2019,
31: 091005.
doi: 10.11884/HPLPB201931.190042
Abstract:
We present and demonstrate a fiber-optic sensor based on single-ended detection that measures both temperature and refractive index. The cladding of the two microsphere-structured fibers is spliced together, and the end of the fiber is coated with an aluminum film to increase reflection, thereby forming a microsphere structure sensing head. The experimental results show that the temperature sensitivity and refractive index of the device can reach 50.77 pm/℃ and -21.94 nm/RIU, respectively. This work presents a low-cost, high-resolution and simple fiber-based approach to versatile sensing applications.
We present and demonstrate a fiber-optic sensor based on single-ended detection that measures both temperature and refractive index. The cladding of the two microsphere-structured fibers is spliced together, and the end of the fiber is coated with an aluminum film to increase reflection, thereby forming a microsphere structure sensing head. The experimental results show that the temperature sensitivity and refractive index of the device can reach 50.77 pm/℃ and -21.94 nm/RIU, respectively. This work presents a low-cost, high-resolution and simple fiber-based approach to versatile sensing applications.
2019,
31: 091006.
doi: 10.11884/HPLPB201931.190252
Abstract:
Accurate focus positioning of a laser beam is an important basis for improving laser engraving, cutting and welding accuracy, but the traditional methods are not fit for automatically finding high-power laser focuses. The plasma caused by laser ablating metal is able to emit a large amount of ultraviolet radiation. Therefore, in this paper a focus automatic positioning method for high-power infrared lasers is proposed and the relevant device is fabricated with a GaN Schottky photodiode as sensor and a 304 stainless-steel laser target as consumable material. As a contrast experiment, the depths of the laser ablation pits on the stainless-steel target are measured with a confocal microscope to find the deepest pits. The focal position difference is 24 μm between the two positioning methods, when the experiments using a 1064-nm-wavelength fiber laser engraving machine with a pulse width of 100 ns, a repetition frequency of 20 kHz and an average power of 10 W.
Accurate focus positioning of a laser beam is an important basis for improving laser engraving, cutting and welding accuracy, but the traditional methods are not fit for automatically finding high-power laser focuses. The plasma caused by laser ablating metal is able to emit a large amount of ultraviolet radiation. Therefore, in this paper a focus automatic positioning method for high-power infrared lasers is proposed and the relevant device is fabricated with a GaN Schottky photodiode as sensor and a 304 stainless-steel laser target as consumable material. As a contrast experiment, the depths of the laser ablation pits on the stainless-steel target are measured with a confocal microscope to find the deepest pits. The focal position difference is 24 μm between the two positioning methods, when the experiments using a 1064-nm-wavelength fiber laser engraving machine with a pulse width of 100 ns, a repetition frequency of 20 kHz and an average power of 10 W.
2019,
31: 093001.
doi: 10.11884/HPLPB201931.190084
Abstract:
In order to broaden the bandwidth of high power microwave radiation antenna, an X-band high power circularly polarized reflectarray antenna constructed by mechanically rotational helical elements is proposed and investigated. The array antenna is fed by an X-band left-handed circularly polarization circular horn. The variable rotation of helical element enables full 360° phase adjustment with low reflection loss. The rectangular reflectarray antenna of 225-element is put forward and simulated. Full-wave simulation result shows that at 9.3 GHz, the antenna gain is 28 dB, the antenna axial ratio is 0.53 dB and the aperture efficiency is 52.6%. In the range of 8.5 to 10.9 GHz, the gain is over 26.8 dB, the axial ratio is below 1.14 dB, and both the 1-dB gain bandwidth and the 40% aperture efficiency bandwidth are over 21%. The power handling capacity of the reflectarray antenna is found to be 207 MW in vacuum.
In order to broaden the bandwidth of high power microwave radiation antenna, an X-band high power circularly polarized reflectarray antenna constructed by mechanically rotational helical elements is proposed and investigated. The array antenna is fed by an X-band left-handed circularly polarization circular horn. The variable rotation of helical element enables full 360° phase adjustment with low reflection loss. The rectangular reflectarray antenna of 225-element is put forward and simulated. Full-wave simulation result shows that at 9.3 GHz, the antenna gain is 28 dB, the antenna axial ratio is 0.53 dB and the aperture efficiency is 52.6%. In the range of 8.5 to 10.9 GHz, the gain is over 26.8 dB, the axial ratio is below 1.14 dB, and both the 1-dB gain bandwidth and the 40% aperture efficiency bandwidth are over 21%. The power handling capacity of the reflectarray antenna is found to be 207 MW in vacuum.
2019,
31: 093002.
doi: 10.11884/HPLPB201931.190077
Abstract:
According to the miniaturization and high performance, the characteristic of a second-order bandpass filter (BPF) with in-line ports based on dual-mode square-shaped resonator is researched, and higher-order BPFs with in-line ports using single-mode resonators and dual-mode resonators are proposed. The proposed filters can be modeled by the box-like coupling scheme, which can realize flexible frequency responses. Moreover, the positions of transmission zeros (TZs) can be easily adjusted to satisfy different applications. An additional TZ can be achieved by the proposed filter in box-like topology for the parasitic coupling in the diagonal cross-coupling path. To verify the proposed structure and design method, third-order and fifth-order filters with center frequency of 5.2 GHz are designed, fabricated and measured. The responses of coupling matrix, simulated and measured results are in good agreement, which demonstrates the feasibility of the proposed filters with high performance.
According to the miniaturization and high performance, the characteristic of a second-order bandpass filter (BPF) with in-line ports based on dual-mode square-shaped resonator is researched, and higher-order BPFs with in-line ports using single-mode resonators and dual-mode resonators are proposed. The proposed filters can be modeled by the box-like coupling scheme, which can realize flexible frequency responses. Moreover, the positions of transmission zeros (TZs) can be easily adjusted to satisfy different applications. An additional TZ can be achieved by the proposed filter in box-like topology for the parasitic coupling in the diagonal cross-coupling path. To verify the proposed structure and design method, third-order and fifth-order filters with center frequency of 5.2 GHz are designed, fabricated and measured. The responses of coupling matrix, simulated and measured results are in good agreement, which demonstrates the feasibility of the proposed filters with high performance.
2019,
31: 093201.
doi: 10.11884/HPLPB201931.190161
Abstract:
The failure mechanism of Xilinx's FPGA chip XC7A200T-2FBG676 under RF interference is studied. When RF interference injects into the power supply pins of the FPGA core, it is found that with the increase of interference intensity at the some frequencies, three types of FPGA failures occur successively, namely core failure, I/O failure and configuration failure. Test analysis and HSPICE simulation show that the core failure is due to the poor disturbance immunity of the logic layer of BRAM, the I/O failure is due to the simultaneous distortion of input/output signals under RF interference, and the configuration failure is due to the configuration system reading the wrong configuration enable signal. This study could provide guidance for the electromagnetic compatibility design of this kind of FPGA chip or system, as well as the formulation of electromagnetic immunity detection scheme of this kind of FPGA.
The failure mechanism of Xilinx's FPGA chip XC7A200T-2FBG676 under RF interference is studied. When RF interference injects into the power supply pins of the FPGA core, it is found that with the increase of interference intensity at the some frequencies, three types of FPGA failures occur successively, namely core failure, I/O failure and configuration failure. Test analysis and HSPICE simulation show that the core failure is due to the poor disturbance immunity of the logic layer of BRAM, the I/O failure is due to the simultaneous distortion of input/output signals under RF interference, and the configuration failure is due to the configuration system reading the wrong configuration enable signal. This study could provide guidance for the electromagnetic compatibility design of this kind of FPGA chip or system, as well as the formulation of electromagnetic immunity detection scheme of this kind of FPGA.
2019,
31: 093202.
doi: 10.11884/HPLPB201931.190133
Abstract:
Infrared target tracking is heavily influenced by illumination variation, small size and complex background, and the lack of target information makes the algorithm lose targets easily. Therefore, an algorithm based on convolution features and feature selection method is presented in this paper to track IR targets. First, several filters in target patches of the first frame are used to obtain strong features. Then, the boosting method is utilized to train the features with redundant information, thus, the algorithm performance of accuracy and execution efficiency can be improved. Finally, particle weights are represented by the response of the native Bayes classifier. Experimental results show that the presented algorithm obtains good performance.
Infrared target tracking is heavily influenced by illumination variation, small size and complex background, and the lack of target information makes the algorithm lose targets easily. Therefore, an algorithm based on convolution features and feature selection method is presented in this paper to track IR targets. First, several filters in target patches of the first frame are used to obtain strong features. Then, the boosting method is utilized to train the features with redundant information, thus, the algorithm performance of accuracy and execution efficiency can be improved. Finally, particle weights are represented by the response of the native Bayes classifier. Experimental results show that the presented algorithm obtains good performance.
2019,
31: 093203.
doi: 10.11884/HPLPB201931.180388
Abstract:
A large number of various radar signals in modern warfare make the electromagnetic environment more and more complex. It is urgent to quickly and accurately obtain the category information of the target track from a large number of radar data, and provide accurate and effective information for the battlefield command. The traditional radar-based target recognition method based on human experience or cognition is unable to effectively cope with the ever-changing battlefield and massive data. Based on the characteristics of actual radar data, this paper proposes a logarithmic preprocessing method and constructs a deep learning model based on convolutional neural network. The deep learning model realizes the recognition and detection of the target track in radar confrontation. The built model is tested based on the radar target track data generated by the simulation. Experiments show that the model can effectively detect and identify the target track.
A large number of various radar signals in modern warfare make the electromagnetic environment more and more complex. It is urgent to quickly and accurately obtain the category information of the target track from a large number of radar data, and provide accurate and effective information for the battlefield command. The traditional radar-based target recognition method based on human experience or cognition is unable to effectively cope with the ever-changing battlefield and massive data. Based on the characteristics of actual radar data, this paper proposes a logarithmic preprocessing method and constructs a deep learning model based on convolutional neural network. The deep learning model realizes the recognition and detection of the target track in radar confrontation. The built model is tested based on the radar target track data generated by the simulation. Experiments show that the model can effectively detect and identify the target track.
2019,
31: 093204.
doi: 10.11884/HPLPB201931.190052
Abstract:
Aiming at the problem that there is no unified understanding about the current electromagnetic situational cognition, this paper takes the radar confrontation situation in the electromagnetic situation as the research object, proposes the concept of situational layered cognition, and studies the acquisition and analysis of radar confrontation situation knowledge. To solve the problem of situational knowledge representation, the radar anti-situation knowledge representation model is established, which provides a basis for the subsequent calculation of electromagnetic situational factors and situational representation. This paper also sorts out the relationship between the confrontational situation and the electromagnetic situation, and provides support for the next step of the radar confrontation situation to adapt to the electromagnetic situation.
Aiming at the problem that there is no unified understanding about the current electromagnetic situational cognition, this paper takes the radar confrontation situation in the electromagnetic situation as the research object, proposes the concept of situational layered cognition, and studies the acquisition and analysis of radar confrontation situation knowledge. To solve the problem of situational knowledge representation, the radar anti-situation knowledge representation model is established, which provides a basis for the subsequent calculation of electromagnetic situational factors and situational representation. This paper also sorts out the relationship between the confrontational situation and the electromagnetic situation, and provides support for the next step of the radar confrontation situation to adapt to the electromagnetic situation.
2019,
31: 093205.
doi: 10.11884/HPLPB201931.190159
Abstract:
To evaluate the threat of high-altitude electromagnetic pulse HEMP environment on a shortwave receiving antenna system, pulsed current injection tests for the front-end equipments near the antenna, including some commercial surge protection devices, have been conducted. Both a fast rise-time nanosecond square waveform pulser and a double exponential waveform pulser with high current output, are adopted to check the responses of various surge protection measures. Results show that three protection devices have played essential roles in preventing against HEMP conducted disturbance. Firstly a gas discharge tube at the end of the whip antenna breaks down within a few nanoseconds, since it suffers an overvoltage much higher than its nominal DC breakdown voltage. Then a transient voltage suppressor (TVS) in the commercial signal surge protection device also responses quickly to clamp the line voltage. And the amplifiers in the signal transmission equipments also limit the residual voltage of the disturbance propagating forward, as they are readily to enter the saturation mode under excess inputs. Therefore, the system can withstand either a fast rise-time nanosecond square waveform pulse with an voltage amplitude of 3.5 kV, or a double exponential (20/500 ns) waveform current pulse with an amplitude of 1.8 kA. The only effect is that the latter signal transmission equipment outputs a disturbance signal with a saturated amplitude (< 3 V) which lasts for several microseconds. This implies that, when combining the selected commercial surge protection devices properly, it is practicable to protect similar low working voltage antenna systems against both lightning electromagnetic pulse and HEMP.
To evaluate the threat of high-altitude electromagnetic pulse HEMP environment on a shortwave receiving antenna system, pulsed current injection tests for the front-end equipments near the antenna, including some commercial surge protection devices, have been conducted. Both a fast rise-time nanosecond square waveform pulser and a double exponential waveform pulser with high current output, are adopted to check the responses of various surge protection measures. Results show that three protection devices have played essential roles in preventing against HEMP conducted disturbance. Firstly a gas discharge tube at the end of the whip antenna breaks down within a few nanoseconds, since it suffers an overvoltage much higher than its nominal DC breakdown voltage. Then a transient voltage suppressor (TVS) in the commercial signal surge protection device also responses quickly to clamp the line voltage. And the amplifiers in the signal transmission equipments also limit the residual voltage of the disturbance propagating forward, as they are readily to enter the saturation mode under excess inputs. Therefore, the system can withstand either a fast rise-time nanosecond square waveform pulse with an voltage amplitude of 3.5 kV, or a double exponential (20/500 ns) waveform current pulse with an amplitude of 1.8 kA. The only effect is that the latter signal transmission equipment outputs a disturbance signal with a saturated amplitude (< 3 V) which lasts for several microseconds. This implies that, when combining the selected commercial surge protection devices properly, it is practicable to protect similar low working voltage antenna systems against both lightning electromagnetic pulse and HEMP.
2019,
31: 093206.
doi: 10.11884/HPLPB201931.190134
Abstract:
A mathematical method is proposed to calculate the field distribution theoretically of folded half mode substrate integrated waveguide(FHMSIW) for the first time. The phase constant is also given using an improved multi-line method, verifying its equivalence with conventional waveguide and substrate integrated waveguides. The FHMSIW transmission line properties of resonance effect, quasi-rotational symmetry of two PCB layers and high-pass feature are proposed. An FHMSIW equalizer loaded equivalent HMSIW resonant cavities, and an FHMSIW bandpass filter loaded folded quarter-wave FHMSIW resonators are designed. The two components share the same structure with a little difference. The model analysis, simulated results and measured results are all provided. The FHMSIW equalizer is achieved without increasing extra excitation structures. The measured results show a good performance and are in agreement with the simulated results. Compared with the other planar circuits, these structures have superiorities of small size, simple structure, low loss and high Q, suitable for the miniaturization development, and are easily integrated with other circuits.
A mathematical method is proposed to calculate the field distribution theoretically of folded half mode substrate integrated waveguide(FHMSIW) for the first time. The phase constant is also given using an improved multi-line method, verifying its equivalence with conventional waveguide and substrate integrated waveguides. The FHMSIW transmission line properties of resonance effect, quasi-rotational symmetry of two PCB layers and high-pass feature are proposed. An FHMSIW equalizer loaded equivalent HMSIW resonant cavities, and an FHMSIW bandpass filter loaded folded quarter-wave FHMSIW resonators are designed. The two components share the same structure with a little difference. The model analysis, simulated results and measured results are all provided. The FHMSIW equalizer is achieved without increasing extra excitation structures. The measured results show a good performance and are in agreement with the simulated results. Compared with the other planar circuits, these structures have superiorities of small size, simple structure, low loss and high Q, suitable for the miniaturization development, and are easily integrated with other circuits.
2019,
31: 095001.
doi: 10.11884/HPLPB201931.190152
Abstract:
In this paper, a high voltage and high frequency pulse generator based on metal oxide semiconductor field effect transistor (MOSFET) switch is designed. Several series MOSFETs triggered by optical fiber signal isolation are used as high voltage switches, and the control signal is provided by the FPGA. The generator is composed of the same MOSFET tube, triggered in parallel and in sequence, synchronized with the reference signal. The circuit and working mode overcome the power consumption limitation of the MOSFET tube generator and significantly improve the pulse repetition rate. This paper introduces the working principle and fabrication process of the MHz high voltage pulse generator in detail. The preliminary test was carried out to verify the performance of the generator. Under the high repetition rate of 1 MHz, the output flat-top pulse had the rise time more than 10 ns, the pulse width 100 ns, and the voltage amplitude greater than 1 kV.
In this paper, a high voltage and high frequency pulse generator based on metal oxide semiconductor field effect transistor (MOSFET) switch is designed. Several series MOSFETs triggered by optical fiber signal isolation are used as high voltage switches, and the control signal is provided by the FPGA. The generator is composed of the same MOSFET tube, triggered in parallel and in sequence, synchronized with the reference signal. The circuit and working mode overcome the power consumption limitation of the MOSFET tube generator and significantly improve the pulse repetition rate. This paper introduces the working principle and fabrication process of the MHz high voltage pulse generator in detail. The preliminary test was carried out to verify the performance of the generator. Under the high repetition rate of 1 MHz, the output flat-top pulse had the rise time more than 10 ns, the pulse width 100 ns, and the voltage amplitude greater than 1 kV.
2019,
31: 095101.
doi: 10.11884/HPLPB201931.190072
Abstract:
A beam orbit stability of 0.1 μm is required by the High Energy Photon Source (HEPS). As an important system of the storage ring, the beam position monitors (BPMs), together with the measured data, play an important role in the beam orbit monitoring and stabilization. Resolution of 0.1μm and long-term stability is required for the BPMs. In order to suppress the mechanical deformation caused by mechanical vibration and temperature variation, an independent and stable support system for the BPM-pick-ups is indispensable to have a higher eigen-frequency in lateral, a smaller vibration amplification ratio, and a minimum temperature deformation factor. In this paper, Invar36 alloy is selected as the main material of the support structure since it has good temperature stability. To ease manufacture and installation, the rod and plate structure is selected for the support prototype, and thorough simulation is done to find the optimal structure. With the methods of topology optimization in ANSYS, the structure prototype of the maximum eigen-frequency is found to guide the design of the support. The support is tested in the laboratory. Comparison between the measurements and the simulation results is made for installation improvement. Four methods of installation is tested and the results will provide reference for the support installation in the storage in the future.
A beam orbit stability of 0.1 μm is required by the High Energy Photon Source (HEPS). As an important system of the storage ring, the beam position monitors (BPMs), together with the measured data, play an important role in the beam orbit monitoring and stabilization. Resolution of 0.1μm and long-term stability is required for the BPMs. In order to suppress the mechanical deformation caused by mechanical vibration and temperature variation, an independent and stable support system for the BPM-pick-ups is indispensable to have a higher eigen-frequency in lateral, a smaller vibration amplification ratio, and a minimum temperature deformation factor. In this paper, Invar36 alloy is selected as the main material of the support structure since it has good temperature stability. To ease manufacture and installation, the rod and plate structure is selected for the support prototype, and thorough simulation is done to find the optimal structure. With the methods of topology optimization in ANSYS, the structure prototype of the maximum eigen-frequency is found to guide the design of the support. The support is tested in the laboratory. Comparison between the measurements and the simulation results is made for installation improvement. Four methods of installation is tested and the results will provide reference for the support installation in the storage in the future.
2019,
31: 096001.
doi: 10.11884/HPLPB201931.190023
Abstract:
In order to reflect the behavior of the nuclear materials in the operating reactor veritably and roundly, and to supply reliable data for the safety review of the nuclear materials, the most effective solution is building a fuel test loop (FTL) based on the real pressurized water reactor in the research reactor. To ensure the safety of the fuel test loop and the research reactor, it is necessary to analyze the safety of the fuel test loop during accident transient. This article simulates and analyzes two typical kinds of accidents—small break loss-of-coolant accidents (LOCA) and loss-of-flow accidents (LOFA)—based on the origin design of the fuel test loop in China's Mianyang Research Reactor (CMRR). The peak cladding temperature in cold leg SBLOCA and hot leg small break LOCA is 880.6 ℃ and 367.6 ℃ respectively, which is under the critical value (1204 ℃). During the total LOFA, the MDNBR is greater than 1.5, which means there is no departure from nucleate boiling. In the clamp shaft accident, the cladding temperature is 734.1 ℃, which is less than 1482 ℃. The results obtained are consistent with the safety criteria.
In order to reflect the behavior of the nuclear materials in the operating reactor veritably and roundly, and to supply reliable data for the safety review of the nuclear materials, the most effective solution is building a fuel test loop (FTL) based on the real pressurized water reactor in the research reactor. To ensure the safety of the fuel test loop and the research reactor, it is necessary to analyze the safety of the fuel test loop during accident transient. This article simulates and analyzes two typical kinds of accidents—small break loss-of-coolant accidents (LOCA) and loss-of-flow accidents (LOFA)—based on the origin design of the fuel test loop in China's Mianyang Research Reactor (CMRR). The peak cladding temperature in cold leg SBLOCA and hot leg small break LOCA is 880.6 ℃ and 367.6 ℃ respectively, which is under the critical value (1204 ℃). During the total LOFA, the MDNBR is greater than 1.5, which means there is no departure from nucleate boiling. In the clamp shaft accident, the cladding temperature is 734.1 ℃, which is less than 1482 ℃. The results obtained are consistent with the safety criteria.
2019,
31: 096002.
doi: 10.11884/HPLPB201931.190080
Abstract:
As a part of the reflectometer in China Spallation Neutron Source (CSNS), data acquisition system (DAQ) of 3He tubes detector should not only have basic functions of data readout and processing, but also coordinate the whole operation of spectrometer and interact with other heterogeneous systems stably and reliably. By planning the whole frame, adopting effective methods, optimizing the key components of DAQ system, choosing and integrating appropriate third-party software, DAQ system achieves goals of convenient and flexible operation, having complete functions and running stably, reliably and efficiently. It meets the demands of the reflectometer. The reflectometer with the DAQ has passed national acceptance. By now, this DAQ system has been applied in neutron beam tests on the reflectometer successfully.
As a part of the reflectometer in China Spallation Neutron Source (CSNS), data acquisition system (DAQ) of 3He tubes detector should not only have basic functions of data readout and processing, but also coordinate the whole operation of spectrometer and interact with other heterogeneous systems stably and reliably. By planning the whole frame, adopting effective methods, optimizing the key components of DAQ system, choosing and integrating appropriate third-party software, DAQ system achieves goals of convenient and flexible operation, having complete functions and running stably, reliably and efficiently. It meets the demands of the reflectometer. The reflectometer with the DAQ has passed national acceptance. By now, this DAQ system has been applied in neutron beam tests on the reflectometer successfully.
2019,
31: 096003.
doi: 10.11884/HPLPB201931.190016
Abstract:
A high-performance real-time control system is designed for magnet power supply in tokomak, which is based on LabVIEW RT and field programmable gate array (FPGA) techniques. According to the real-time control requirements of the magnetic power supply, a reflective memory card was used to realize real-time data transformation, and a real-time operation system is applied to ensure the reliability and determinism of the power supply system. Then NI DAQ 7813R data acquisition card was used to control thyristor converter. The experimental results of the real-time control system for the power supply are presented, which demonstrate that the control system meets the design requirement and has high-reliability and determinism.
A high-performance real-time control system is designed for magnet power supply in tokomak, which is based on LabVIEW RT and field programmable gate array (FPGA) techniques. According to the real-time control requirements of the magnetic power supply, a reflective memory card was used to realize real-time data transformation, and a real-time operation system is applied to ensure the reliability and determinism of the power supply system. Then NI DAQ 7813R data acquisition card was used to control thyristor converter. The experimental results of the real-time control system for the power supply are presented, which demonstrate that the control system meets the design requirement and has high-reliability and determinism.
