Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and vali...Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.展开更多
An IC+PSSD telescope for the identification of heavy ion reaction products atlow energies is developed,The performence of the IC detector is tested with α-particlesfrom the <sup>241</sup>Am source.The mea...An IC+PSSD telescope for the identification of heavy ion reaction products atlow energies is developed,The performence of the IC detector is tested with α-particlesfrom the <sup>241</sup>Am source.The measured energy resolution is limited by the energy lossstraggling in the gas and is close to optimum value of this kind of detectors.展开更多
为在HIRFL(Heavy Ion Rescarch Facility,Lanzhou)上进行重离子生物效应的研究,我们研制了一种在线平行板雪崩探测器,利用其电极分块的办法可以测定45mm直径束流截面上的均匀度和平均强度,对^(239)Pu α源,当极间距离为3mm,工作气体为1...为在HIRFL(Heavy Ion Rescarch Facility,Lanzhou)上进行重离子生物效应的研究,我们研制了一种在线平行板雪崩探测器,利用其电极分块的办法可以测定45mm直径束流截面上的均匀度和平均强度,对^(239)Pu α源,当极间距离为3mm,工作气体为1kPa的异丁烯,工作电压为750V时,快前置放大器的输出信号幅度可达0.8—1.2V。每个子探测器记录48MeV/u C^(6+)离子时的最高平均计数率为340k计数/s。该探测器结构紧凑,使用方便,经实验使用基本满足研究工作的要求。展开更多
基金supported by the National Key Basic Research Program of China(973 Program)2015CB251002National Natural Science Foundation of China under Grant 51521065,51577145+1 种基金the Fundamental Research Funds for the Central UniversitiesShaanxi Province Natural Science Foundation 2013JM-7010
文摘Influence of the gassing materials, such as PA6, PMMA, and POM on the dielectric properties of air are investigated. In this work, the fundamental electron collision cross section data were carefully selected and validated. Then the species compositions of the air–organic vapor mixtures were calculated based on the Gibbs free energy minimization. Finally, the Townsend ionization coefficient, the Townsend electron attachment coefficient and the critical reduced electric field strength were derived from the calculated electron energy distribution function by solving the Boltzmann transport equation. The calculation results indicated that H;O with large attachment cross sections has a great impact on the critical reduced electric field strength of the air–organic vapor mixtures. On the other hand, the vaporization of gassing materials can help to increase the dielectric properties of air circuit breakers to some degree.
文摘An IC+PSSD telescope for the identification of heavy ion reaction products atlow energies is developed,The performence of the IC detector is tested with α-particlesfrom the <sup>241</sup>Am source.The measured energy resolution is limited by the energy lossstraggling in the gas and is close to optimum value of this kind of detectors.
