A design for an efficient monochromatic electron source for Inverse Photoemission Spectroscopy （IPES） apparatus is described. The electron source consists of a BaO cathode, a focus electrostatic lens, a hemispherica...A design for an efficient monochromatic electron source for Inverse Photoemission Spectroscopy （IPES） apparatus is described. The electron source consists of a BaO cathode, a focus electrostatic lens, a hemispherical deflection monochromator （HDM）, and a transfer electrostatic lens. The HDM adopts a “slit-in and slit-out” structure and the degradation of first-order focusing is corrected by two electrodes between the two hemispheres, which has been investigated by both analytical methods and electron-ray tracing simulations using the SIMION program. Through the focus lens, the HDM, and the standard five-element transfer lens, an optimal energy resolution is estimated to be about 53 MeV with a beam flux of 27 μA. Pass energy （P.E.） of 10 eV and 5 eV are discussed, respectively.展开更多
This work is concerned with ion beam dynamics and compares the emittance to aberration ratios of two-and three-electrode extraction systems. The study is conducted with the aid of Version 7 of SIMION 3D ray-tracing so...This work is concerned with ion beam dynamics and compares the emittance to aberration ratios of two-and three-electrode extraction systems. The study is conducted with the aid of Version 7 of SIMION 3D ray-tracing software. The beam dependence on various parameters of the extraction systems is studied and the numerical results lead to qualitative conclusions. Ion beam characteristics using diode and triode extraction systems are investigated with the aid of the computer code SIMION 3 D, Version 7.0. The diode （two electrode extraction system） and triode （three- electrode extraction, acceleration-deceleration system） extraction systems are designed and optimized with different geometric parameters of the electrode system, voltage applied to the extraction electrode, and plasma parameters inside the ion source chamber, as well as by the ion beam space charge. This work attempts to describe the importance of the acceleration-deceleration extraction system. It shows that besides an increase of the beam energy, the ion beam has lower emittance than the two-electrode extraction system. Ion beams of the highest quality are extracted whenever the half-angular divergence is minimum for which the perveance current intensity and the extraction gap have optimum value. Knowing the electron temperature of the plasma is necessary to determine plasma potential and the exact beam energy.展开更多
静电四级透镜具有优越的电子光学聚焦成像性能,单一静电四极透镜可实现电子束线聚焦,组合静电四极透镜系统拥有点聚焦的能力。文中对实现点聚焦的双静电四极透镜系统相关参数进行了计算,利用电子光学软件SIMION仿真发现,静电四极透镜之...静电四级透镜具有优越的电子光学聚焦成像性能,单一静电四极透镜可实现电子束线聚焦,组合静电四极透镜系统拥有点聚焦的能力。文中对实现点聚焦的双静电四极透镜系统相关参数进行了计算,利用电子光学软件SIMION仿真发现,静电四极透镜之间的畸变场与两端的边缘场引起的像差会严重影响系统聚焦成像质量。仿真分析了系统像差与发射电子初动能的关系。结果表明:系统在保证点聚焦的情况下,增加电子发射初动能可以有效减小系统像差;当电子初动能增加至1×105 e V时,最大发散角为2°的电子束在聚焦平面上的弥散斑减小至3.2μm×28μm。展开更多
Microchannel plates (MCP) are widely used for particle detection. The gain of chevron MCPs is related to geometrical parameters, but no study has been done through SIMION simulation. The purpose of this study is to mo...Microchannel plates (MCP) are widely used for particle detection. The gain of chevron MCPs is related to geometrical parameters, but no study has been done through SIMION simulation. The purpose of this study is to model a chevron MCP and its secondary emission process using SIMION and determine the relationship between microchannel plate gain, voltage, channel bias angle, and diameter. Two geometry files simulated MCP electric field and shape, and a Lua program simulated secondary emission. Simulation results showed that MCP gain is proportional to voltage, angles between 5 and 15 degrees maximize gain, and gain is inversely proportional to the diameter. This study accurately simulates a chevron MCP and yields the relationship between gain, voltage, channel bias angle, and diameter. Further studies are needed to simulate electron trajectories for improved precision.展开更多
A micro sensor chip of High-field Asymmetric Waveform Ion Mobility Spectrometry(FAIMS) was designed and fabricated by inductively coupled plasma(ICP) etching on the both sides of silicon and double silicon-glass bondi...A micro sensor chip of High-field Asymmetric Waveform Ion Mobility Spectrometry(FAIMS) was designed and fabricated by inductively coupled plasma(ICP) etching on the both sides of silicon and double silicon-glass bonding,with dimensions of 18.8 mm×12.4 mm×1.2mm.The sample ions were created at ambient pressure by VUV lamp ion source,which was equipped with a 10.6 eV photo discharge lamp(λ=116.5 nm).The 2-pentanone was adopted to illustrate the influences of high-field rectangular asymmetric waveform voltage amplitude,frequency and carrier gas flow rate on the performance of FAIMS sensor chip.The experiment results showed that with the frequency or carrier gas flow rate increasing,or voltage amplitude decreasing,the FAIMS sensitivity increases,and that the resolution decreases with the increasing of the frequency or flow rate.The FAIMS simulation results based on the SIMION software was in agreement with the experimental results.The FAIMS detection sensitivity experiment showed that the FAIMS sensor chip can detect positive and negative ions simultaneously,and has detection sensitivity as low as 0.1 ppm for acetic acid.展开更多
基金Supported by National Natural Science Foundation of China(11175239)One Hundred Person Project of Chinese Academy of SciencesInstrument design and development Project of CAS:Spin rosolved Inverse-PES system
文摘A design for an efficient monochromatic electron source for Inverse Photoemission Spectroscopy （IPES） apparatus is described. The electron source consists of a BaO cathode, a focus electrostatic lens, a hemispherical deflection monochromator （HDM）, and a transfer electrostatic lens. The HDM adopts a “slit-in and slit-out” structure and the degradation of first-order focusing is corrected by two electrodes between the two hemispheres, which has been investigated by both analytical methods and electron-ray tracing simulations using the SIMION program. Through the focus lens, the HDM, and the standard five-element transfer lens, an optimal energy resolution is estimated to be about 53 MeV with a beam flux of 27 μA. Pass energy （P.E.） of 10 eV and 5 eV are discussed, respectively.
文摘This work is concerned with ion beam dynamics and compares the emittance to aberration ratios of two-and three-electrode extraction systems. The study is conducted with the aid of Version 7 of SIMION 3D ray-tracing software. The beam dependence on various parameters of the extraction systems is studied and the numerical results lead to qualitative conclusions. Ion beam characteristics using diode and triode extraction systems are investigated with the aid of the computer code SIMION 3 D, Version 7.0. The diode （two electrode extraction system） and triode （three- electrode extraction, acceleration-deceleration system） extraction systems are designed and optimized with different geometric parameters of the electrode system, voltage applied to the extraction electrode, and plasma parameters inside the ion source chamber, as well as by the ion beam space charge. This work attempts to describe the importance of the acceleration-deceleration extraction system. It shows that besides an increase of the beam energy, the ion beam has lower emittance than the two-electrode extraction system. Ion beams of the highest quality are extracted whenever the half-angular divergence is minimum for which the perveance current intensity and the extraction gap have optimum value. Knowing the electron temperature of the plasma is necessary to determine plasma potential and the exact beam energy.
文摘静电四级透镜具有优越的电子光学聚焦成像性能,单一静电四极透镜可实现电子束线聚焦,组合静电四极透镜系统拥有点聚焦的能力。文中对实现点聚焦的双静电四极透镜系统相关参数进行了计算,利用电子光学软件SIMION仿真发现,静电四极透镜之间的畸变场与两端的边缘场引起的像差会严重影响系统聚焦成像质量。仿真分析了系统像差与发射电子初动能的关系。结果表明:系统在保证点聚焦的情况下,增加电子发射初动能可以有效减小系统像差;当电子初动能增加至1×105 e V时,最大发散角为2°的电子束在聚焦平面上的弥散斑减小至3.2μm×28μm。
文摘Microchannel plates (MCP) are widely used for particle detection. The gain of chevron MCPs is related to geometrical parameters, but no study has been done through SIMION simulation. The purpose of this study is to model a chevron MCP and its secondary emission process using SIMION and determine the relationship between microchannel plate gain, voltage, channel bias angle, and diameter. Two geometry files simulated MCP electric field and shape, and a Lua program simulated secondary emission. Simulation results showed that MCP gain is proportional to voltage, angles between 5 and 15 degrees maximize gain, and gain is inversely proportional to the diameter. This study accurately simulates a chevron MCP and yields the relationship between gain, voltage, channel bias angle, and diameter. Further studies are needed to simulate electron trajectories for improved precision.
基金supported by the National Natural Science Foundation of China (Grant Nos 60706030, 20827007)the National Basic Research Program of China ("973" Project)(Grant No 2007CB310504)
文摘A micro sensor chip of High-field Asymmetric Waveform Ion Mobility Spectrometry(FAIMS) was designed and fabricated by inductively coupled plasma(ICP) etching on the both sides of silicon and double silicon-glass bonding,with dimensions of 18.8 mm×12.4 mm×1.2mm.The sample ions were created at ambient pressure by VUV lamp ion source,which was equipped with a 10.6 eV photo discharge lamp(λ=116.5 nm).The 2-pentanone was adopted to illustrate the influences of high-field rectangular asymmetric waveform voltage amplitude,frequency and carrier gas flow rate on the performance of FAIMS sensor chip.The experiment results showed that with the frequency or carrier gas flow rate increasing,or voltage amplitude decreasing,the FAIMS sensitivity increases,and that the resolution decreases with the increasing of the frequency or flow rate.The FAIMS simulation results based on the SIMION software was in agreement with the experimental results.The FAIMS detection sensitivity experiment showed that the FAIMS sensor chip can detect positive and negative ions simultaneously,and has detection sensitivity as low as 0.1 ppm for acetic acid.
