共查询到20条相似文献,搜索用时 281 毫秒
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介绍了一台基于电偏转扫描方法的强流离子束发射度仪,讨论了发射度仪硬件的系统构成和设计要点,该发射度仪采用阶梯型电压对通过前缝的束流进行扫描来获得束流散角信息。并对测量计算软件和数据处理方法进行了介绍,采用了先扣除本底,再设置阈值的方法进行数据处理。处理后的数据利用程序可获得均方根和边界发射度、束斑大小、最大正负散角以及发射度相图。利用该发射度仪对ECR离子源引出的强流质子束的发射度进行了测量,并对测量数据进行了分析。对于引出电压为50 kV、脉冲重复频率为166 Hz、脉冲宽度为1 ms、平均束流强度为4 mA的质子脉冲束,其归一化均方根发射度为0.27 pmm·mrad。 相似文献
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为全面研究ECR(Electron Cyclotron Resonance)离子源引出的高电荷态离子束流品质,获取ECR离子源引出离子束流的横向四维相空间分布,提高向加速器的注入效率,中国科学院近代物理研究所研制了一台高精度Pepper Pot型发射度测量仪PEMiL(Pepper pot Emittance Meter in Lanzhou)。根据使用需求,利用KBr晶体喷涂技术取代传统的CsI闪烁体成像技术,解决了束流光斑重叠效应,获得了边界清晰的束流图像;并开发了相应的数据处理分析程序,以分析处理得到的束流横向四维相空间分布。利用PEMiL获得了75 keV,170 eμA的O5+束流横向四维发射度。分析结果表明:PEMiL测量分析后的束流发射度结果可靠性高,荧光屏电荷累积效应造成的发射度差异不超过25%,PEMiL可作为ECR离子源引出离子束流品质诊断的有效装置。 相似文献
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高增益、短波长自由电子激光器需要发射度低、峰值电流高的短脉冲电子束流.采用发射度补偿技术,设计了一台S波段、一个半腔体的光阴极微波电子枪以用于建议中的SDUV-FEL装置.POISSON,SUPERFISH和PARMELA程序的计算表明:当微脉冲电量为2nC时,这种设计能产生εn,rms=2.3π·mm·mrad、Ek=4.8MeV的电子束流.报道了该枪的设计考虑和模拟结果. 相似文献
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3.5 MeV 注入器是“神龙一号”直线感应加速器的束源,在注入器束流调试中,首先通过数值模拟方法,初步确定束流过聚焦和聚焦不足两种极端情况下引出线圈输运磁场峰值的变化范围;然后以注入器出口束流波形为参考,通过实验调试找到了这两种情况下引出线圈输运磁场峰值的实际配置;再通过测量束流的剖面或发射度,在这两种配置中选定一个折中的引出线圈磁场配置,并最终确定了注入器输运磁场的总体配置。经过调试完成后的注入器束流为3.6 MeV,流强为2.8 kA,归一化边发射度为1 040 mm·mrad,达到了预期的指标。 相似文献
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We present here a self consistent theory of small amplitude double layers associated with electrostatic ion cyclotron waves in a plasma containing hot electrons, cold ions and traversed by an ion beam. It has been shown that compressive type of double layers solution exists when θb (beam temperature) < αb (beam concentration) < 1. 相似文献
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介绍了现阶段两种用于聚焦离子束系统的离子源——液态金属离子源和气体场发射离子源的基本原理, 并对比了它们的优缺点。由于目前这两种离子源都难以满足纳米加工领域不断提高的技术要求, 因此提出了一种用于聚焦离子束的新型离子源——电子束离子源, 并介绍了电子束离子源的基本原理, 给出了设计参数、 模拟结果(20 kV的Ar+离子束, 发射度约为5.8×10-5·mm·mrad, 束斑约为1 μm)和初步的实验结果。 There are two kinds of ion sources, Liquid Metal Ion Source and Gas Field Ion Source, used to provide ion beams for the Focus Ion Beam system. The working mechanism of the two kinds of sources is presented and their advantages and disadvantages are summarized. With the rapid development in the nano technology, the requirements are hardly met with these two kinds of ion sources. Therefore, a new kind of ion source, electron beam ion source, is developed for the Focus Ion Beam system. The basic principle of the electron beam ion source is introduced and the design parameters, the result of the simulation (20 kV Ar+, extracted emittance is 5.8×10-5π·mm·mrad, raduis of the ion beam about 1 μm.) and the primary experimental results are presented 相似文献
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The power balance in the inductive discharge of a radio-frequency ion source is worked out by calculating the power losses caused by plasma deposition on the surfaces bordering it, by the power consumed for positive-ion generation and pre-acceleration, by eddy currents, and by propellant-atom excitation. The relationship between the minimal consumption of high-frequency power per unit of ion current of the thruster and electron temperature and geometric parameters of the gas-discharge chamber is presented. 相似文献
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《中国物理快报》2017,(1)
The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than T_e/(γi2 T_(i2))~(1/2), where Te is the electron temperature, and γ_(i2) and T_(i2) represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature. 相似文献
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G. Weyer 《Hyperfine Interactions》1986,27(1-4):249-262
Some developments in applications of Mössbauer spectroscopy to investigate ion-implanted radioactive source isotopes in solids are presented. Emphasis is layed on impurity and defect studies in metals and semiconductors. The particular role of Mössbauer spectroscopy in comparison to and in combination with other analytical techniques is illustrated. Recently developed on-line implantation techniques are described, their merits and prospects are discussed. 相似文献
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G. Langouche 《Hyperfine Interactions》1992,68(1-4):95-106
The extreme sensitivity of Mössbauer Spectroscopy to the local atomic and electronic configuration around ion implanted Mössbauer probes is demonstrated in a number of recent defect configuration studies in semiconductors and metals. A surge of interest is observed towards Mössbauer studies on high dose implantations connected with materials research: recent studies are reviewed dealing with ion beam synthesis, ion beam modification and ion beam mixing of materials. 相似文献
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W. K. Hensinger D. M. Segal R. C. Thompson 《Applied physics. B, Lasers and optics》2012,107(4):881-881
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利用最新自行研制的电扫描发射度探测系统, 在ECR离子源上进行了一系列关于ECR离子源引出束流发射度的研究. 这套电扫描发射度探测系统安装在中国科学院近代物理研究所(兰州)的LECR3试验平台的束运线上. 试验中, 通过测量相关参数, 研究了磁场、微波、掺气效应及负偏压效应等对引出束流发射度的影响. 利用实验所得的结果与关于ECR等离子体和离子源束流发射度的半经验理论, 分析推导了离子源各可调参数与ECR等离子体的直接关系, 这为分析探索ECR离子源的工作机制提供了一定的参考依据. 相似文献