共查询到19条相似文献,搜索用时 828 毫秒
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在实验室天体物理研究中,电子束离子阱(EBIT)是极端紫外(EUV)和X射线波段能谱分析的重要实验平台,其中EBIT中心残余的中性气体对离子产生存在显著影响。研究了阱区中心残余中性气体对电荷态分布的影响,发现阱区中心残余中性气体和高电荷态离子之间的电荷/能量交换过程不仅影响离子的电荷分布, 而且对激发函数(离子分布比例随电子能量关系曲线)有着极大的影响。利用电离平衡分析方法成功诊断出阱区中心区域残留的中性气体分子数密度,以及内腔室的真空度。 相似文献
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综述了双辉光离子渗金属这一新颖的等离子体表面冶金技术,介绍了双辉光交链增强型放电这一独特的放电现象,讨论了双辉光交链增强的条件和交链增强的机理以及它在双辉光离子渗金属技术中的作用,介绍了双辉光离子渗金属的实验研究结果及在国内工业化推广应用的情况,评述了它的应用前景及在推广应用中应注意的问题。 相似文献
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在采用双辉光放实施的离子渗金属加工中,存在强烈的边角效应。从等离子体性能入手,在实验研究了这种边角效应,并分析了该种边角效应产生的原因,讨论了它对双辉光放电离子渗金属和加工的影响。 相似文献
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蛋白质是生物体内含量最丰富的生物大分子物质,在人体代谢中扮演重要的角色,它的分析测定在医学和生物学研究中有着重要的意义。荧光方法是研究蛋白质结构,功能和定性定量分析的一种重要方法,而稀土离子及其配合物是荧光分析中最常用的探针技术。本文介绍了近十几年来稀土离子及其配合物荧光探针在蛋白质分析中的应用。 相似文献
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介绍一种使用闪烁体耦合电子倍增电荷耦合器件(EMCCD)的方式对离子进行记录的汤姆逊能谱仪,可实现对离子能谱的实时单发测量。同时,该谱仪利用倾斜电极板对离子进行偏转,可减少由于离子打在电极板上产生的电磁噪声,能够提高实验结果的信噪比。该谱仪在北京大学4.5 MV静电加速器和2×6MV串列加速器上进行了标定实验,测量了闪烁体将离子转化成光子后的探测效率,实验结果也验证了该谱仪的可行性和稳定性。该汤姆逊谱仪将用于北京大学激光加速器CLAPA对离子束流的测量研究。 相似文献
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本文介绍一台采用双潘宁型多电荷重离子源的200kV重离子加速器,简述它在GaP光探测器的研制、聚合物材料和金属材料的离子注入改性等方面的研究与应用。 相似文献
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The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed. The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombination spectroscopy and VUV/x-ray spectroscopy. The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region, ion-induced fragmentation mechanisms of molecules, hydrogen-bound and van de Waals bound clusters, interference, and phase information observed in ion-atom/molecule collisions. With this achievements, two aspects of theoretical studies related to low energy and relativistic energy collisions are presented. The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed. At the end of this review, some future prospects of research related to highly charged ions are proposed. 相似文献
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W. Quint J. Dilling S. Djekic H. Häffner N. Hermanspahn H.-J. Kluge G. Marx R. Moore D. Rodriguez J. Schönfelder G. Sikler T. Valenzuela J. Verdú C. Weber G. Werth 《Hyperfine Interactions》2001,132(1-4):453-457
HITRAP is a planned ion trap facility for capturing and cooling of highly charged ions produced at GSI in the heavy-ion complex
of the UNILAC-SIS accelerators and the ESR storage ring. In this facility heavy highly charged ions up to uranium will be
available as bare nuclei, hydrogen-like ions or few-electron systems at low temperatures. The trap for receiving and studying
these ions is designed for operation at extremely high vacuum by cooling to cryogenic temperatures. The stored highly charged
ions can be investigated in the trap itself or can be extracted from the trap at energies up to about 10 keV/q. The proposed
physics experiments are collision studies with highly charged ions at well-defined low energies (eV/u), high-accuracy measurements
to determine the g-factor of the electron bound in a hydrogen-like heavy ion and the atomic binding energies of few-electron systems, laser
spectroscopy of HFS transitions and X-ray spectroscopy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Mass analyzed highly charged ion beams of energy ranging from a few keV to a few MeV plays an important role in various aspects
of research in modern physics. In this paper a unique low energy ion beam facility (LEIBF) set up at Nuclear Science Centre
(NSC) for providing low and medium energy multiply charged ion beams ranging from a few keV to a few MeV for research in materials
sciences, atomic and molecular physics is described. One of the important features of this facility is the availability of
relatively large currents of multiply charged positive ions from an electron cyclotron resonance (ECR) source placed entirely
on a high voltage platform. All the electronic and vacuum systems related to the ECR source including 10 GHz ultra high frequency
(UHF) transmitter, high voltage power supplies for extractor and Einzel lens are placed on a high voltage platform. All the
equipments are controlled using a personal computer at ground potential through optical fibers for high voltage isolation.
Some of the experimental facilities available are also described. 相似文献
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根据Penning阱存储离子的探测原理,系统分析了阱内离子信号及信号本身的噪声、实验仪器及探测电路的噪声干扰,采用适当的品质因数和电子束流,得到较高信噪比和分辨率的离子谱。为深入开展Hn^+(n≥3)对离子的形成机制、离子与中性气体原子或分子碰撞过程等问题的研究创造了更好的条件。 相似文献
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利用质量分离的低能离子束沉积技术,得到了非晶碳膜.所用离子能量为50—200eV,衬底温度从室温到800℃.在沉积的能量范围内,衬底为室温时薄膜为类金刚石,表面非常光滑;而600℃下薄膜主要是石墨成分,表面粗糙.沉积能量大于140eV,800℃时薄膜表面分立着高度取向的、垂直衬底表面、相互平行的开口碳管.用高分辨电子显微镜看到了石墨平面的垂直择优取向,离子的浅注入和应力是这种优先取向的主要机理.
关键词:
非晶碳
表面形貌
质量分离低能离子束 相似文献
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H. Häffner N. Hermanspahn P. Indelicato H. J. Kluge E. Lindroth V. Natarajan W. Quint S. Stahl J. Verdú G. Werth 《Hyperfine Interactions》2000,127(1-4):271-276
The mass of a highly charged ion is the sum of the mass of the nucleus, the mass of the electrons and the electronic binding
energies. High accuracy mass measurements on highly charged ions in a sequence of different charge states yield informations
on atomic binding energies, i.e., the ionisation potentials. In our contribution we discuss the possibility of determining
atomic binding energies of highly charged ions to better than 20 eV via cyclotron frequency measurements in a Penning trap.
At this level of accuracy different contributions to the binding energies, like relativistic corrections, Breit corrections
and QED corrections, can be measured.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献