镍海绵浸渍氧化物阴极在北京质子加速器中的应用和研究

描述了北京质子直线加速器（ＢＰＬ）双等离子体源中使用的一种低加热功率镍海绵浸渍氧化物阴极的结构、底金属表面的海绵化处理以及浸渍涂料的制备方法。介绍了该阴极的激活方法和实验结果。讨论了影响氧化物阴极使用寿命的主要因素。该阴极的使用寿命已达２１１０ｈ，可供引出脉冲束流２００ｍＡ。     

低能高束流氩离子源的结构及性能

离子源技术是等离子体研究中的一项重要内容,而低能大束流源则是离子源技术研究中的一个重要方向,因为这样的源在离子束刻蚀、离子束溅射镀膜以及荷能粒子与物质相互作用方面都有广泛的应用;本文采用空心阴极空心阳极结构,用热阴极电子发射弧放电驱动并用磁场约束产生等离子体,用曲面发射引出离子束,研制成了氩气放电溅射离子源;研究了灯丝加热电流、弧压对弧流的影响和弧流与工作气体压力对离子束引出的影响规律.离子源的引出电压在0-4.0 kV之间连续可调,最大引出束流为100 mA,束斑面积为φ6.0 cm,以Ti为溅射靶时的最大溅射沉积率为0.45 nm/s,离子源可连续工作160 h.     

750KeV,50mAH—RFQ预注入器调整结果

文章介绍西德DESY研究所750keV负氢离子预注入器的调整结果。通过提高弧流,磁控管型H~-离子源可以引出18keV,60—80mA的H~-脉冲离子流。发现外部磁场可以在螺旋管内部感生一个方向大体相同的磁场。在低能输运段,离子束空间电荷中和所需的时间约100μs。在离子源引出束流约65mA时,经两对螺旋管聚焦和RFQ加速后可以获得能量为750±8.8keV,聚团半宽度约0.8ns,发射度约3mm·mrad,束流为52mA的脉冲H~-流;其中33mA以上的束流处于1mm·mrad以内。     

中子管用PIG负氢离子源及其束流引出实验研究

PIG离子源用于中子管引出正离子,但在使用过程中存在一定问题,如单原子离子比低、靶材料溅射严重及功耗大等。为解决这些问题,提高中子管的寿命和稳定性,本文设计一种中子管用PIG负氢离子源,并对其束流引出进行实验研究。分别测量了离子源的磁场、不同阴极材料及引出阴极离子发射孔径对引出负氢离子束流的影响。实验数据表明,该负氢离子源可用于制作性能指标良好的中子管。     

300keV,5电极负离子束系统的数值模拟研究

根据负离子-中性束注入器中强流负离子束引出、加速系统的特点,建立了为辅助设计强流负离子束系统而对其进行数值模拟研究的模型和计算程序,计算了负离子束和伴随引出的电子束在系统电、磁场共同作用下的运动行为,研究了系统束流密度、负离子初始温度以及负离子剥离损失和末电极孔位移等相关参数对负离子束光学特性的影响,并对系统的电、磁场位形进行了优化。对300keV,5电极负离子束系统的初步优化结果表明:该系统磁场可将伴随引出的电子束在低能下偏转到作为电子接收极的引出电极上;对引出流密度为21mA·cm~(-2)的H~-离子束,当H~-离子在引出区的剥离损失为20％时,由系统出射的各小束的均方根角度和85％小束的散角可分别达到0.327°和0.460°。     

等离子喷涂硼化镧阴极电子枪

一、引言现代大型医用电子直线加速器电子枪的设计有如下特点: 1.要求电子枪束流在大范围内连续可调。对于一个二极型电子枪系统,枪必须工作在温度限制区域内,故阴极发射的稳定性十分重要。2.行波电子直线加速器通常采用可拆性结构,这就要求阴极必须有较好的抗中毒特性。     

纵向多灯丝电子帘加速器的束流不均匀度

束流不均匀度是电子帘加速器束流性能的一重要指标。影响束流不均匀度的主要因素是加速器结构中各电极（阴极、反射极、栅极、阳极）的电位、形状及其相对位置。本工作针对1台纵向多灯丝电子帘加速器的实际结构参数,计算其束流不均匀度,通过分析和比较,讨论了进一步改善束流不均匀度的可能途径,为改进电子帘加速器的设计提供了参考。     

放射性核束靶源系统研究进展

一台利用HI-13串列加速器作为驱动加速器提供初级束流轰击厚靶产生放射性核束的ISOL试验装置已经建成并开展了离线实验研究。初步研究了源磁场、阳极电压、阴极电流、进气量等参数对离子源效率的影响,初步的测量结果显示,靶源系统电离、引出及传输的总效率大于0.7％,进一步提高效率的工作正在进行。     

MEVVA型金属离子源

本文报道金属蒸发真空孤放电（ＭＥＶＶＡ）型金属离子源的研究结果。阴极材料分别使用了Ａｌ、Ｔｉ、Ｆｅ和Ｃｕ。阴极触发脉冲１２ｋＶ，脉冲宽度９０μｓ，脉冲重复率１－５次／ｓ。引出束流脉冲宽度３００μｓ。当引出电压为２８ｋＶ时，可引出Ａｌ、Ｔｉ、Ｆｅ和Ｃｕ离子流强度分别为２３０ｍＡ、２５０ｍＡ、２８０ｍＡ和３００ｍＡ     

15-20mA负氢离子源的设计

制约强流质子回旋加速器技术发展的一个主要因素是离子源的束流强度以及束流品质，为提高引出流强、改善束流品质，中国原子能科学研究院一直致力于离子源的发展。2000年建成了平均流强5．2mA的负氢离子源，束流发射度达到了0．65πnm-mrad，2004年建成了高于10mA的负氢离子源。为进一步提高束流流强，满足中国原子能科学研究院串列加速器升级工程的需求，在原有10mA负氢离子源基础上设计1台新的离子源，将平均引出束流提高到15-20mA。     

Characteristics of Single Cathode Cascaded Bias Voltage Arc Plasma

A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the plasma optical emission.The cathode chamber cooling scheme is also modified to be naturally cooled only by light emission without cooling water to improve the optical thin performance in the optical path.A single-parameter physical model has been developed to describe the power dissipated in the cascaded bias voltage arc discharge argon plasmas,which have been investigated by utilizing optical emission spectroscopy(OES) and Langmuir probe.In the experiments,discharge currents from 50 A to 100 A,argon flow rates from 800 sccm to 2000 sccm and magnetic fields of 0.1 T and 0.2 T were chosen.The results show:(a) the relationship between the averaged resistivity and the averaged current density exhibits an empirical scaling law as η∝ j~(-0.63369) and the power dissipated in the arc has a strong relation with the filling factor;(b) through the quartz,the argon ions optical emission lines have been easily observed and are dominating with wavelengths between 340 nm and 520 nm,which are the emissions of Ar~+-434.81 nm and Ar~+-442.60 nm line,and theintensities are increasing with the arc current and decreasing with the inlet argon flow rate;and(c) the electron density and temperature can reach 2.0 × 10~(19) m~(-3) and 0.48 eV,respectively,under the conditions of an arc current of 90 A and a magnetic field of 0.2 T.The half-width of the n_e radial profile is approximatively equal to a few Larmor radii of electrons and can be regarded as the diameter of the plasma jet in the experiments.     

Cooling enhancement of planar-balanced magnetron cathode

In physical vapor deposition on a magnetron cathode, temperature of sensitive components must be kept under threshold limit, so as to ensure the cathode reliability,the process reproducibility, and the best quality of thin films.This can be achieved by an adequate design to enhance the dissipation of heat generated at the cathode. In this paper,temperature distribution and streamlines velocity of the cathode coolant inside a cathode magnetron are analyzed by using CFD solver ANSYS FLUENT in the single-phase method in combination with k–e standards turbulent model.The results show that the design is appropriate under the calculation parameters, and for high heat densities some improvements are necessary to enhance heat dissipation and keep temperature under the threshold limit.     

A cathodic arc enhanced middle-frequency magnetron sputter system for deposition of hard protective coatings

1Introduction Hard coating is a type of coating that includes metallic nitrides,metallic carbides,diamond,dia-mond-like carbon(DLC),and ceramic.These coatings can effectively reduce friction coefficients and wear rates of the workpieces and increase surface hardness,toughness,and resistance to chemical corrosion;hence,they are widely used as protective coatings on cutting tools and on wear-exposed components.[1-3]Plasma chemical vapor deposition(PCVD),magnetron sput-tering,and cathode arc d…     

Analysis of Effects of the Arc Voltage on Arc Discharges in a Cathode Ion Source of Neutral Beam Injector

A hot cathode bucket ion source is used for the EAST(experimental advanced superconducting tokamak)neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by the electric field formed by the arc voltage,which is applied between the arc chamber of the ion source and the cathode.This paper analyzes the effects of arc voltage on the arc discharge in a hot cathode high current ion source.     

Parametric Study on Arc Behavior of Magnetically Diffused Arc

A model coupling the plasma with a cathode body is applied in the simulation of the diffuse state of a magnetically rotating arc.Four parametric studies are performed:on the external axial magnetic field (AMF),on the cathode shape,on the total current and on the inlet gas velocity.The numerical results show that:the cathode attachment focuses in the center of the cathode tip with zero AMF and gradually shifts off the axis with the increase of AMF;a larger cathode conical angle corresponds to a cathode arc attachment farther away off axis;the maximum values of plasma temperature increase with the total current;the plasma column in front of the cathode tip expands more severely in the axial direction,with a higher inlet speed;the cathode arc attachment shrinks towards the tip as the inlet speed increases.The various results are supposed to be explained by the joint effect of coupled cathode surface heating and plasma rotating flow.     

Three-dimensional non-equilibrium modeling of a DC multi-cathode arc plasma torch

In this paper, a three-dimensional non-equilibrium steady arc model is used to investigate the temperature, velocity and electromagnetic field in multi-cathode arc torch, and the formation mechanism of a large-area, uniform and diffused arc plasma is analyzed. The numerical simulation results show that a large volume plasma region can be formed in the central region of the generator during discharge. During this process, the maximum electron temperature appears near the cathode and in the central convergence region, while the maximum heavy particle temperature only appears in the central convergence region. This phenomenon is consistent with the experimental arc images. Near the cathode tip, the arc column is in a contraction state. In the area slightly away from the cathode, the six arc columns begin to join together. In the plasma generator, there is a large-scale current distribution in all directions of X, Y and Z, forming a stable arc plasma with a wide range of diffusion. The calculated electron temperature distribution is in good agreement with the measured electron temperature. The results suggest that the largearea diffused arc plasma in the multi-cathode arc torch is the combined effect of current distribution, convection heat transfer and heat conduction.     

Hot Cathode’s Working Voltage Impacts on the Operation of High Current Ion Source

High power ion source is one of the important parts of the neutral beam injection. It produces high energy beam by extracting and accelerating ions from its arc chamber. The hot cathode (filaments) in the arc chamber of the ion source operates in two modes. Operation mode of the cathode has great effect on the stable operation of the ion source. Based on the theory of hot cathode and experimental results, this paper presents the operation results (beam current, arc efficiency) of an ion source with various cathode temperatures (controlled by voltage applied to the cathode).     

六硼化镧阴极在双等离子体离子源中的应用

一、引言早在50年代初,J.M.Lafferty就研究了六硼化镧阴极的电子发射特性。70年代中期以后,六硼化镧阴极广泛地应用于现代技术的许多领域。例如,等离子体发生器、强流离子源(包括用于聚变研究中的中性束注入源)、电子显微镜、质谱仪和一些电子器件(真空规管,热电离变换器等)。     

间热式大面积六硼化镧中空阴极

介绍了适用于强流离子源的间热式大面积六硼化镧中空阴极。在１５ｃｍ双潘宁离子湖泊 上放电特性研究表明，该阴极性能良好，能可靠工作，使用过程中多次暴露于大气中，发射性能并未变坏，加热功率为１．４５ｋＷ，ＬａＢ６发射电流密度为２０Ａ／ｃｍ＾２，放电电流４００Ａ，脉冲宽度３０ｍｓ，放电波形重复性很好。使用１００ｈ后，发射体尺寸无明显变化。