An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of ...An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of fast ions in the HL-2A/3 tokamak.The E//B NPA contains three main units,i.e.the stripping unit,the analyzing unit and the detection unit.A gas stripping chamber was adopted as the stripping unit.The results of the simulations and beam tests for the stripping chamber are presented.Parallel electric and magnetic fields provided by a NdFeB permanent magnet and two parallel electric plates were designed and constructed for the analyzing unit.The calibration of the magnetic and electric fields was performed using a 50 kV electron cyclotron resonance ion source(ECRIS)platform.The detection unit consists of 32lutetium-yttrium oxyorthosilicate(LYSO)detector modules arranged in two rows.The response functions ofα,hydrogen ions(H^(+),H_(2)^(+)and H_(3)^(+))andγfor a detector module were measured with^(241)Am,^(137)Cs and^(152)Eu sources together with the 50 kV ECRIS platform.The overall results indicate that the designed E//B NPA device is capable of measuring the intensity of neutral hydrogen and deuteron atoms with energy higher than 20 keV.展开更多
Readout electronics is developed for a prototype time-of-flight(TOF) ion composition spectrometer for in situ measurement of the mass/charge distributions of major ion species from 200 to 100 ke V/e in space plasma.By...Readout electronics is developed for a prototype time-of-flight(TOF) ion composition spectrometer for in situ measurement of the mass/charge distributions of major ion species from 200 to 100 ke V/e in space plasma.By utilizing a constant fraction discriminator(CFD) and time-to-digital converter(TDC), challenging dynamic range measurements were performed with high time resolution and event rates. CFD was employed to discriminate the TOF signals from the micro-channel plate and channel electron multipliers. TDC based on the combination of counter and OR-gate delay chain was designed in a highreliability flash field programmable gate array. Owing to the non-uniformity of the delay chain, a correction algorithm based on integral nonlinearity compensation was implemented to reduce the time uncertainty. The test results showed that the electronics achieved a low timingerror of < 200 ps in the input range from 35 to 500 m V for the CFD, and a time resolution of ～550 ps with time uncertainty < 180 ps after correction and a time range of6.4 ls for the TDC. The TOF spectrum from an electron beam experiment of the impacting N_2 gas further indicated the good performance of this readout electronic.展开更多
An ultra-high vacuum （UHV） compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope （STM） to study ...An ultra-high vacuum （UHV） compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope （STM） to study the spatially localized electron energy spectrum on a surface. A tip-sample system composed of a piezo-driven field-emission tungsten tip and a sample of highly ordered pyrolytic graphite （HOPG） is employed to test the performance of the spectrometer. Two-dimensional images of the energy-resolved and angle-dispersed electrons backscattered from the surface of HOPG are obtained, the performance is optimized and the spectrometer is calibrated. A complete electron energy loss spectrum covering the elastic peak to the secondary electron peaks for the HOPG surface, acquired at a tip voltage of -140 V and a sample current of 0.5 pA, is presented, demonstrating the viability of the spectrometer.展开更多
Recently, the demand for REEs （rare earth elements） has been heavily increasing, as they are used in many high-tech products （e.g., because of their specific magnetic behavior）. As a result, the supply situation f...Recently, the demand for REEs （rare earth elements） has been heavily increasing, as they are used in many high-tech products （e.g., because of their specific magnetic behavior）. As a result, the supply situation for REEs is worsening and the world market is depending on Chinese exports, so that it may be worthwhile to recycle e-waste （electronic waste） in European countries. This article describes an analytical method to analyze REEs in different kinds of e-waste with the help of a simultaneous ICP-OES （ICP optical emission spectrometer）. The task is challenging because samples show significant differences in terms of major, minor and trace element concentrations. Depending on the field of application, the level of matrix elements and target elements differs completely, resulting in a wide variety of spectral interferences. The method presented in this article allows an accurate quantification of REEs as well as a high sample throughput. In addition to REEs, other elements of economic interest can be determined in the same way. The development of a sample preparation process is another important issue and considered as well.展开更多
北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个...北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个斜长石成分剖面电子探针分析表明,它们众数成分为 An=29的更长石。但是,其成分变化范围极宽(An=14～56),晶体内不同部位的成分有很大差别,出现正常环带的 An 值较低(14～42),内环带的 An 值较高(24～56)的特殊情况,指示斜长石结晶环境的改变,暗示具有富钙基性岩浆的加入。从岩体边部到中心,斜长石 An 牌号逐渐降低,但相邻岩相单元之间有较大的重叠,表明不同岩石单元中的斜长石成分主要受控于岩浆成分的变化,与分离结晶作用无关。斜长石的韵律性环带、特别是内环带的发育则是岩浆混合作用机制的有力证据。基性岩浆的反复注入不仅改变寄主岩浆的成分,而且也控制了它的温度、定位机制和岩石的结构特征。因此,房山岩体的形成过程还包含了镁铁质岩浆多次注入的历史,并且从外到里基性岩浆的作用逐渐减弱。展开更多
基金supported by the National Magnetic Confinement Fusion Energy R&D Program of China(No.2018YFE0310200)National Natural Science Foundation of China(Nos.11705242,11805138 and 12175156)the Fundamental Research Funds for the Central Universities in China(Nos.YJ201820 and YJ201954)。
文摘An E//B neutral particle analyzer(NPA)has been designed and is under development at Sichuan University and Southwestern Institute of Physics.The main purpose of the E//B NPA is to measure the distribution function of fast ions in the HL-2A/3 tokamak.The E//B NPA contains three main units,i.e.the stripping unit,the analyzing unit and the detection unit.A gas stripping chamber was adopted as the stripping unit.The results of the simulations and beam tests for the stripping chamber are presented.Parallel electric and magnetic fields provided by a NdFeB permanent magnet and two parallel electric plates were designed and constructed for the analyzing unit.The calibration of the magnetic and electric fields was performed using a 50 kV electron cyclotron resonance ion source(ECRIS)platform.The detection unit consists of 32lutetium-yttrium oxyorthosilicate(LYSO)detector modules arranged in two rows.The response functions ofα,hydrogen ions(H^(+),H_(2)^(+)and H_(3)^(+))andγfor a detector module were measured with^(241)Am,^(137)Cs and^(152)Eu sources together with the 50 kV ECRIS platform.The overall results indicate that the designed E//B NPA device is capable of measuring the intensity of neutral hydrogen and deuteron atoms with energy higher than 20 keV.
基金supported by the National Key Scientific Instrument and Equipment Development Projects of the National Natural Science Foundation of China(No.41327802)China Mars Project
文摘Readout electronics is developed for a prototype time-of-flight(TOF) ion composition spectrometer for in situ measurement of the mass/charge distributions of major ion species from 200 to 100 ke V/e in space plasma.By utilizing a constant fraction discriminator(CFD) and time-to-digital converter(TDC), challenging dynamic range measurements were performed with high time resolution and event rates. CFD was employed to discriminate the TOF signals from the micro-channel plate and channel electron multipliers. TDC based on the combination of counter and OR-gate delay chain was designed in a highreliability flash field programmable gate array. Owing to the non-uniformity of the delay chain, a correction algorithm based on integral nonlinearity compensation was implemented to reduce the time uncertainty. The test results showed that the electronics achieved a low timingerror of < 200 ps in the input range from 35 to 500 m V for the CFD, and a time resolution of ～550 ps with time uncertainty < 180 ps after correction and a time range of6.4 ls for the TDC. The TOF spectrum from an electron beam experiment of the impacting N_2 gas further indicated the good performance of this readout electronic.
基金supported by the National Basic Research Program of China (Grant No. 2010CB923301)the National Natural Science Foundation of China (GrantNos. 11327404 and 11174268)
文摘An ultra-high vacuum （UHV） compatible electron spectrometer employing a double toroidal analyzer has been de- veloped. It is designed to be combined with a custom-made scanning tunneling microscope （STM） to study the spatially localized electron energy spectrum on a surface. A tip-sample system composed of a piezo-driven field-emission tungsten tip and a sample of highly ordered pyrolytic graphite （HOPG） is employed to test the performance of the spectrometer. Two-dimensional images of the energy-resolved and angle-dispersed electrons backscattered from the surface of HOPG are obtained, the performance is optimized and the spectrometer is calibrated. A complete electron energy loss spectrum covering the elastic peak to the secondary electron peaks for the HOPG surface, acquired at a tip voltage of -140 V and a sample current of 0.5 pA, is presented, demonstrating the viability of the spectrometer.
文摘Recently, the demand for REEs （rare earth elements） has been heavily increasing, as they are used in many high-tech products （e.g., because of their specific magnetic behavior）. As a result, the supply situation for REEs is worsening and the world market is depending on Chinese exports, so that it may be worthwhile to recycle e-waste （electronic waste） in European countries. This article describes an analytical method to analyze REEs in different kinds of e-waste with the help of a simultaneous ICP-OES （ICP optical emission spectrometer）. The task is challenging because samples show significant differences in terms of major, minor and trace element concentrations. Depending on the field of application, the level of matrix elements and target elements differs completely, resulting in a wide variety of spectral interferences. The method presented in this article allows an accurate quantification of REEs as well as a high sample throughput. In addition to REEs, other elements of economic interest can be determined in the same way. The development of a sample preparation process is another important issue and considered as well.
文摘北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个斜长石成分剖面电子探针分析表明,它们众数成分为 An=29的更长石。但是,其成分变化范围极宽(An=14～56),晶体内不同部位的成分有很大差别,出现正常环带的 An 值较低(14～42),内环带的 An 值较高(24～56)的特殊情况,指示斜长石结晶环境的改变,暗示具有富钙基性岩浆的加入。从岩体边部到中心,斜长石 An 牌号逐渐降低,但相邻岩相单元之间有较大的重叠,表明不同岩石单元中的斜长石成分主要受控于岩浆成分的变化,与分离结晶作用无关。斜长石的韵律性环带、特别是内环带的发育则是岩浆混合作用机制的有力证据。基性岩浆的反复注入不仅改变寄主岩浆的成分,而且也控制了它的温度、定位机制和岩石的结构特征。因此,房山岩体的形成过程还包含了镁铁质岩浆多次注入的历史,并且从外到里基性岩浆的作用逐渐减弱。
