Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high precision.However,they cannot easily withstand high temperatures exceeding 150 ℃...Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high precision.However,they cannot easily withstand high temperatures exceeding 150 ℃ because of intrinsic material limits.Herein,we proposed and executed a systematic and full-process study of Sic-based MEMS pressure sensors that operate stably from-50 to 300 ℃.First,to explore the nonlinear piezoresistive effect,the temperature coefficient of resistance(TCR)values of 4H-SiC piezoresistors were obtained from-50 to 500 ℃.A conductivity variation model based on scattering theory was established to reveal the nonlinear variation mechanism.Then,a piezoresistive pressure sensor based on 4H-SiC was designed and fabricated.The sensor shows good output sensitivity(3.38 mVN/MPa),accuracy(0.56%FS)and low temperature coefficient of sensitivity(TCS)(-0.067%FS/℃)in the range of-50 to 300 ℃.In addition,the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H_(2)SO_(4) and NaOH solutions and its radiation tolerance under 5 W X-rays.Accordingly,the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction,deep well dilling,aeroengines and gas turbines.展开更多
Purpose The continuous-wave(CW)linear accelerator,SSC-Linac,has been put into operation successfully as the new injector of Separate Sector Cyclotron(SSC)for Heavy Ion Research Facility in Lanzhou(HIRFL).The SSC-Linac...Purpose The continuous-wave(CW)linear accelerator,SSC-Linac,has been put into operation successfully as the new injector of Separate Sector Cyclotron(SSC)for Heavy Ion Research Facility in Lanzhou(HIRFL).The SSC-Linac is operated at the frequency of 53.667 MHz,which is the four times of the SSC operating frequency.In order to improve the longitudinal capture efficiency and increase the beam current extracted from the SSC,an independent multi-harmonics buncher(MHB)operating at a fundamental frequency of 13.417 MHz had been designed and manufactured.Method This buncher adopts the dual-gap structure and sawtooth waveform is generated by multi-harmonics synthetized technology.Beam dynamics simulation with MHB was carried out and discussed in this paper.Furthermore,the beam commissioning using 84Kr14+had been performed on SSC-Linac.Results and conclusion The measured maximum capture efficiency 86.5%was obtained,which was well agreed with the simulation results.Due to the successful commissioning of MHB and the outstanding-performance of SSC-Linac,the extracted beam current from SSC has been improved one order of magnitude higher than before.展开更多
基金support from National Natural Science Foundation of China(No.52175517,51720105016)Zhejiang Lab(2022MG0AB03)+2 种基金China Postdoctoral Science Foundation(No.2017M610634)The Recruitment Program of Global Experts(Grant No.WQ2017610445)Innovation Capability Support Program of Shaanxi Province(No.2021TD-23).
文摘Microelectromechanical system(MEMS)pressure sensors based on silicon are widely used and offer the benefits of miniaturization and high precision.However,they cannot easily withstand high temperatures exceeding 150 ℃ because of intrinsic material limits.Herein,we proposed and executed a systematic and full-process study of Sic-based MEMS pressure sensors that operate stably from-50 to 300 ℃.First,to explore the nonlinear piezoresistive effect,the temperature coefficient of resistance(TCR)values of 4H-SiC piezoresistors were obtained from-50 to 500 ℃.A conductivity variation model based on scattering theory was established to reveal the nonlinear variation mechanism.Then,a piezoresistive pressure sensor based on 4H-SiC was designed and fabricated.The sensor shows good output sensitivity(3.38 mVN/MPa),accuracy(0.56%FS)and low temperature coefficient of sensitivity(TCS)(-0.067%FS/℃)in the range of-50 to 300 ℃.In addition,the survivability of the sensor chip in extreme environments was demonstrated by its anti-corrosion capability in H_(2)SO_(4) and NaOH solutions and its radiation tolerance under 5 W X-rays.Accordingly,the sensor developed in this work has high potential to measure pressure in high-temperature and extreme environments such as are faced in geothermal energy extraction,deep well dilling,aeroengines and gas turbines.
基金supported by the National Natural Science Foundation of China(No.11375243)Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06G373).
文摘Purpose The continuous-wave(CW)linear accelerator,SSC-Linac,has been put into operation successfully as the new injector of Separate Sector Cyclotron(SSC)for Heavy Ion Research Facility in Lanzhou(HIRFL).The SSC-Linac is operated at the frequency of 53.667 MHz,which is the four times of the SSC operating frequency.In order to improve the longitudinal capture efficiency and increase the beam current extracted from the SSC,an independent multi-harmonics buncher(MHB)operating at a fundamental frequency of 13.417 MHz had been designed and manufactured.Method This buncher adopts the dual-gap structure and sawtooth waveform is generated by multi-harmonics synthetized technology.Beam dynamics simulation with MHB was carried out and discussed in this paper.Furthermore,the beam commissioning using 84Kr14+had been performed on SSC-Linac.Results and conclusion The measured maximum capture efficiency 86.5%was obtained,which was well agreed with the simulation results.Due to the successful commissioning of MHB and the outstanding-performance of SSC-Linac,the extracted beam current from SSC has been improved one order of magnitude higher than before.
