Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanic...Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanical structure of the feedthroughs is designed according to the Computer Simulation Technology(CST)simulation results.Resultsandconclusions Small batches of feedthroughs are manufactured,and the structure is optimized based on mechanical,vacuum,electromagnetic,and other characteristic test results.The performance improved significantly owing to optimization through batch product testing,and quality control-related information from several manufacturers is obtained,which provide a foundation for the development of BPMs for HEPS.展开更多
Based on the minimum settling time （MST） theory and step-response analysis of the second order system in active switched capacitor （SC） networks, a novel clock feedthrough frequency compensation （CFFC） method fo...Based on the minimum settling time （MST） theory and step-response analysis of the second order system in active switched capacitor （SC） networks, a novel clock feedthrough frequency compensation （CFFC） method for a folded-cascode OTA is proposed. The damping factor r/is adjusted by using MOS capacitors to introduce clock feedthrough so that the OTA can obtain the MST state and thus achieve fast settling. Research results indicate that the settling time of the compensated OTA is reduced by 22.7% ;as the capacitor load varies from 0.5 to 2.5pF,the improved settling time increases approximately linearly from 3.62 to 4.46ns： for VGA application, fast settling can also be achieved by modifying the MOS capacitor value accordingly when the closed loop gain of the compensated OTA varies.展开更多
Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency （ICRF） antenna in EAST, along with an electro-analysis and thermal structural analysis, is pre- sented. The electric field, the voltage...Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency （ICRF） antenna in EAST, along with an electro-analysis and thermal structural analysis, is pre- sented. The electric field, the voltage standing wave ratio （VSWR） and the stresses in the vacuum feedthrough are studied. A method using the rings of oxygen-free copper as the cushion and macro- beam plasma arc welding is applied in the assembly to protect the ceramic from being damaged during welding. The vacuum leak test on the prototype of vacuum feedthrough is introduced.展开更多
Optical emission spectroscopy parallel to the axis of a low-pressure radio-frequency discharge in nitrogen was realized, i. e. end-on instead of customary side-on measurements. A specially designed optical feedthrough...Optical emission spectroscopy parallel to the axis of a low-pressure radio-frequency discharge in nitrogen was realized, i. e. end-on instead of customary side-on measurements. A specially designed optical feedthrough was fabricated and installed co-planar with the anode elec- trode, allowing non-invasive observations perpendicular to the plasma sheath. The principal ex- cited species flowing towards the grounded electrode were identified and, by assuming Boltzmann distributions, the vibrational temperature of the molecules on the X1 ∑＋/g and C3Ⅱu levels was estimated under various operating conditions.展开更多
Thermal-actuation and piezoresistive-detection effects have been employed to pump the effective quality factor of MEMS resonators,targeting simple self-oscillation and better sensing performance in the air.However,the...Thermal-actuation and piezoresistive-detection effects have been employed to pump the effective quality factor of MEMS resonators,targeting simple self-oscillation and better sensing performance in the air.However,the ratio of the pumped effective quality factor to the inherent mechanical quality factor,crucial for characterizing the amplification,is hard to obtain.The main difficulty stems from hidden Lorentz peaks caused by feedthrough effects and the pump effect once the current is applied.In this paper,we demonstrated the presence of high-order harmonic components in the output of thermal-piezoresistive resonators when the oscillation amplitude is sufficiently large.By utilizing second-order harmonics,we achieved the improvement in signal-to-bias ratio of,20.85 dB compared to that without feedthrough cancellation and 9.67 dB compared to that using a de-embedded method when the bias current is 6.20 mA.Furthermore,the inherent mechanical quality factor is extracted at a low current of 1.8 mA with a value of 5800 using the second-order harmonics,and a nearly two orders of magnitude enhancement in Q factor can be obtained before entering the self-oscillation regime.An amplitude bias instability as good as 55 ppm and a frequency bias instability as good as 10 ppb are realized in the nonlinear operation regime with a pumped effective quality factor of 576k.The paper contributes to the fundamental understanding of the Q pump effect together with harmonic analysis of the thermal-piezoresistive resonators and also pushes forward the development of low-power consumption self-oscillation resonant sensors.展开更多
Purpose The superfast kickers are required for the HEPS storage ring on-axis injection system due to its very small dynamic aperture.A 750-mm-long stripline pair type of kicker prototype was researched and developed t...Purpose The superfast kickers are required for the HEPS storage ring on-axis injection system due to its very small dynamic aperture.A 750-mm-long stripline pair type of kicker prototype was researched and developed to demonstrate achieved performance of bandwidth,impedance,kicker strength,field uniformity and beam power loss.Methods The cross sections of the kicker main body and the end of taper part are optimized for a good impedance matching and field uniformity.3D simulation further optimizes the taper part to minimize the beam power loss and maintain a lower reflection.The high-voltage feedthrough is also designed and optimized by 3D CST.RF and high-voltage measurements are taken to verify the design of kicker assembly.Results The testing transmission odd-mode impedance is 50±0.5Ω,the even-mode impedance is 60±0.5Ω,and return loss is less than−13 dB.The peak voltage and the rise time of pulse width inserting kicker assembly just decrease 3%of 20 kV and slow down 80 ps,respectively.Conclusions RF testing results agree well with the simulation ones,which meet the design specification.The kicker assembly works well at±20 kV pulse.展开更多
The heat transfer characteristics of feedthrough flange under high alternating current excitation were investigated by threedimensional finite element model.The correlations between the heat transfer behaviors and sys...The heat transfer characteristics of feedthrough flange under high alternating current excitation were investigated by threedimensional finite element model.The correlations between the heat transfer behaviors and system parameters including applied current,ceramic thickness and working time were discussed comprehensively.A remarkable absorbed power beyond 100 W in flange would be produced by the electromagnetic field from wires.Under natural cooling condition,there is an obvious temperature rise about 40℃in the flange center after 10 min of current excitation.Three types of water cooling solutions acting on flange surface,e.g.line type,circle type and S type solutions,were proposed to reduce the flange temperature under high alternating current and long working time condition.By the S type water cooling mode,the best cooling effect can be achieved that the maximum temperature rise is about 20℃and the average temperature rise is less than 5℃.展开更多
基金funded by the Youth Innovation Promotion Association CAS(Nos.2019013 and Y202005)the National Natural Science Foundation of China(No.11975254).
文摘Purpose Based on the requirements of the High Energy Photon Source(HEPS),the key components for strip-type and button-type beam position monitors(BPMs)and feedthroughs are designed and manufactured.Method The mechanical structure of the feedthroughs is designed according to the Computer Simulation Technology(CST)simulation results.Resultsandconclusions Small batches of feedthroughs are manufactured,and the structure is optimized based on mechanical,vacuum,electromagnetic,and other characteristic test results.The performance improved significantly owing to optimization through batch product testing,and quality control-related information from several manufacturers is obtained,which provide a foundation for the development of BPMs for HEPS.
文摘Based on the minimum settling time （MST） theory and step-response analysis of the second order system in active switched capacitor （SC） networks, a novel clock feedthrough frequency compensation （CFFC） method for a folded-cascode OTA is proposed. The damping factor r/is adjusted by using MOS capacitors to introduce clock feedthrough so that the OTA can obtain the MST state and thus achieve fast settling. Research results indicate that the settling time of the compensated OTA is reduced by 22.7% ;as the capacitor load varies from 0.5 to 2.5pF,the improved settling time increases approximately linearly from 3.62 to 4.46ns： for VGA application, fast settling can also be achieved by modifying the MOS capacitor value accordingly when the closed loop gain of the compensated OTA varies.
文摘Detailed design of the vacuum feedthrough for the ion cyclotron radio frequency （ICRF） antenna in EAST, along with an electro-analysis and thermal structural analysis, is pre- sented. The electric field, the voltage standing wave ratio （VSWR） and the stresses in the vacuum feedthrough are studied. A method using the rings of oxygen-free copper as the cushion and macro- beam plasma arc welding is applied in the assembly to protect the ceramic from being damaged during welding. The vacuum leak test on the prototype of vacuum feedthrough is introduced.
文摘Optical emission spectroscopy parallel to the axis of a low-pressure radio-frequency discharge in nitrogen was realized, i. e. end-on instead of customary side-on measurements. A specially designed optical feedthrough was fabricated and installed co-planar with the anode elec- trode, allowing non-invasive observations perpendicular to the plasma sheath. The principal ex- cited species flowing towards the grounded electrode were identified and, by assuming Boltzmann distributions, the vibrational temperature of the molecules on the X1 ∑＋/g and C3Ⅱu levels was estimated under various operating conditions.
基金supported by the National Key R&D Program of China No.2023YFB3208800the National Science Foundation of China No.52475606 and 52435012+1 种基金the Fundamental Research Funds for the Central Universities,Innovation Capability Support Program of Shaanxi(Program No.2024RS-CXTD-17)Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2023JC-XJ-07).
文摘Thermal-actuation and piezoresistive-detection effects have been employed to pump the effective quality factor of MEMS resonators,targeting simple self-oscillation and better sensing performance in the air.However,the ratio of the pumped effective quality factor to the inherent mechanical quality factor,crucial for characterizing the amplification,is hard to obtain.The main difficulty stems from hidden Lorentz peaks caused by feedthrough effects and the pump effect once the current is applied.In this paper,we demonstrated the presence of high-order harmonic components in the output of thermal-piezoresistive resonators when the oscillation amplitude is sufficiently large.By utilizing second-order harmonics,we achieved the improvement in signal-to-bias ratio of,20.85 dB compared to that without feedthrough cancellation and 9.67 dB compared to that using a de-embedded method when the bias current is 6.20 mA.Furthermore,the inherent mechanical quality factor is extracted at a low current of 1.8 mA with a value of 5800 using the second-order harmonics,and a nearly two orders of magnitude enhancement in Q factor can be obtained before entering the self-oscillation regime.An amplitude bias instability as good as 55 ppm and a frequency bias instability as good as 10 ppb are realized in the nonlinear operation regime with a pumped effective quality factor of 576k.The paper contributes to the fundamental understanding of the Q pump effect together with harmonic analysis of the thermal-piezoresistive resonators and also pushes forward the development of low-power consumption self-oscillation resonant sensors.
基金Funding was provided by National Natural Science Founda-tion of China(Grant Nos.11475200 and 11675194).
文摘Purpose The superfast kickers are required for the HEPS storage ring on-axis injection system due to its very small dynamic aperture.A 750-mm-long stripline pair type of kicker prototype was researched and developed to demonstrate achieved performance of bandwidth,impedance,kicker strength,field uniformity and beam power loss.Methods The cross sections of the kicker main body and the end of taper part are optimized for a good impedance matching and field uniformity.3D simulation further optimizes the taper part to minimize the beam power loss and maintain a lower reflection.The high-voltage feedthrough is also designed and optimized by 3D CST.RF and high-voltage measurements are taken to verify the design of kicker assembly.Results The testing transmission odd-mode impedance is 50±0.5Ω,the even-mode impedance is 60±0.5Ω,and return loss is less than−13 dB.The peak voltage and the rise time of pulse width inserting kicker assembly just decrease 3%of 20 kV and slow down 80 ps,respectively.Conclusions RF testing results agree well with the simulation ones,which meet the design specification.The kicker assembly works well at±20 kV pulse.
基金supported by the National Natural Science Foundation of China(Grant Nos.51734008,51522102,51327901 and 51474175)the National Key R&D Program of China(Grant No.2018YFB2001800)the Shannxi Key Industry Chain Program(Grant No.2019ZDLGY05-10)。
文摘The heat transfer characteristics of feedthrough flange under high alternating current excitation were investigated by threedimensional finite element model.The correlations between the heat transfer behaviors and system parameters including applied current,ceramic thickness and working time were discussed comprehensively.A remarkable absorbed power beyond 100 W in flange would be produced by the electromagnetic field from wires.Under natural cooling condition,there is an obvious temperature rise about 40℃in the flange center after 10 min of current excitation.Three types of water cooling solutions acting on flange surface,e.g.line type,circle type and S type solutions,were proposed to reduce the flange temperature under high alternating current and long working time condition.By the S type water cooling mode,the best cooling effect can be achieved that the maximum temperature rise is about 20℃and the average temperature rise is less than 5℃.
