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).     

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.     

Electrical Parameter Measurement System of the Ion Source for EAST Neutral Beam Injector

Neutral beam injection (NBI) is recognized as one of the most effective means of plasma heating. A virtual instrument (VI) has been designed to provide electrical parameter measurement for the ion source of EAST-NBI. The VI is written using the National Instruments LabVIEW graphical programming language. All data acquisition (DAQ) is accomplished using ADLINK DAQ hardware interface and Task-oriented DAQ Driver. The VI can measure filament voltage, filament current, arc voltage, arc current and accelerating voltage etc. The data obtained from the VI are feedback of the ion source operation state and helpful to direct the operation parameter optimization of the ion source.     

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.     

基于多元线性回归模型的中性束质子比分析

中性束质子比的高低对其注入等离子体后的加热效果具有重要的影响。实验中,强流离子源的灯丝电压、弧压、进气量等宏观运行参数决定了中性束质子比的大小。以东方超环中性束注入测试台束引出实验为基础,利用多元线性回归模型对引出中性束质子比进行分析,建立了影响中性束质子比的预测方程,并对该模型的正确性进行了检验。结果表明,中性束质子比可利用以灯丝电压和弧压为自变量的多元线性回归模型进行分析,灯丝电压是影响质子比的关键参数,弧压次之。     

弗里曼源热阴极弧放电在高温下应用中的几个问题

介绍弗里曼源在典型气体流量下弧室内、源缝口侧、引出缝口后３００ｍｍ处和监控处的真 空度间的关系，纯灯丝热和弧放电热引起的弧室内壁、料炉末端的温升分布特性，以及微渗水 蒸汽使高温灯丝氧化对放电特性的影响。同时研究了几种特殊气体放电的氦离子辅助以及灯丝 电极夹下垂引起的灯丝外短路问题。     

Investigation of Arc Regulation of Hot Cathode Ion Source with Langmuir Probe

The neutral beam injector (NBI) is one of the main plasma heating methods for nuclear fusion devices. For the hot cathode high current ion source, the arc current and beam current tends to increase during the beam pulse. In order to gets long pulse beam extraction, the arc regulation technology is employed. The Langmuir probes are installed on the experimental advanced superconducting tokamak-NBI ion source, to feedback control the arc discharge and beam extraction. The experimental results show that, the long pulse of 100 s ion beam is extracted with beam energy of 30 keV with arc regulation. More the results are presented in this paper.     

强流双潘宁离子源弧特性研究

针对22cm双潘宁离子源,研究了其弧流与放电调节参数的关系以及二次进气的效果,确定了拉长弧流脉宽、提高弧流强度与稳定性、达成离子源合适工作状态的措施,为获得高品质的弧流提供了依据.离子源弧特性测试研究结果对提高强流离子源的工作性能以实现NBI系统强流准稳态运行有重要的指导意义.     

串列加速器358型双等离子体离子源改进及性能研究

为提高北京师范大学GIC4117型串列加速器358型双等离子体离子源束流强度及灯丝使用寿命,改进了离子源灯丝涂覆材料中Ba、Sr、Ca元素的占比、灯丝涂覆方法及离子源保护措施。讨论了在不同灯丝电流下,进气量、弧流、约束磁铁电流对离子源输出束流强度的影响。灯丝累积使用寿命达到200 h以上,靶室束流强度较原来采用860A溅射源提高约500倍。同时本文对358型双等离子体离子源调试过程中的异常断弧情况进行了分析和改进。     

大功率离子源负载端数据采集系统研制

大功率离子源是整个中性束注入装置的核心部件。离子源灯丝、弧等关键部件的运行状态对系统实验参数设定、故障判断至关重要。为了实时监控灯丝、弧的运行状态,设计了一款大功率离子源负载端数据采集系统。系统采用伏频(V/F)转换技术实现了采样信号的远程隔离传输。PXI系统和Lab VIEW将采样信号进行实时显示。实验结果表明,在直流和调制注入模式下,系统实现了离子源灯丝和弧电压的远程实时监控。     

Comparison of pulse-modulated and continuous operation modes of a radio-frequency inductive ion source

The paper describes an experimental study of the characteristics of a pulse-modulated radiofrequency(RF) discharge sustained at low pressures, typical of the operating modes of RF gridded ion sources. The motivation for the study is the question of whether the RF pulsemodulated mode can increase the efficiency of the ion source. The ion current values extracted from an RF inductive ion source operating in continuous and pulse-modulated modes were compared. The experimental data were also compare...     

Versatile plasma ion source with an internal evaporator

A novel construction of an ion source with an evaporator placed inside a plasma chamber is presented. The crucible is heated to high temperatures directly by arc discharge, which makes the ion source suitable for substances with high melting points. The compact ion source enables production of intense ion beams for wide spectrum of solid elements with typical separated beam currents of ∼100-150 μA for Al⁺, Mn⁺, As⁺ (which corresponds to emission current densities of 15-25 mA/cm²) for the extraction voltage of 25 kV. The ion source works for approximately 50-70 h at 100% duty cycle, which enables high ion dose implantation. The typical power consumption of the ion source is 350-400 W. The paper presents detailed experimental data (e.g. dependences of ion currents and anode voltages on discharge and filament currents and magnetic flux densities) for Cr, Fe, Al, As, Mn and In. The discussion is supported by results of Monte Carlo method based numerical simulation of ionisation in the ion source.     

IMPROVEMENT ON PROPERTY AND WORKING LIFE OF FREEMAN SOURCE

The magnetic mirror field caused by a pair of mild steel circular in 15mm diameter,2mm thickness placed outside the discharge chamber can increase the atom ion ratio of nitrogen from 66% to 81% ,and the heating filament current can be decreased from 130A down to 100A for a new filament of 2mm in diameter,The Mo shield cylinders in 14mm diameter put behind the reflect cathode surrounding the BN insulator prevent the metallization of BN insulators,and result in increasing the stability of arc discharge till to the end of filament working life.Because it restricts the deposition of the sputtered W and Mo atoms on the BN insulator,and maintains a high resistance of 70 MΩ between the anode and cathode.The combination of cathode shield cylinder and forming magnetic mirror field improves the running property,life of the Freeman source being about 40h.     

Characteristics of a High Current P.I.G. Ion Source at Low Gas Pressure

The characteristics of a 10 cm P.I.G. (Penning ionization gauge) discharge and its application as an ion source at a low pressure are given. Using a hot cathode two regions of operation are found, one above and the other below 1 micron. Pulsed ion current reaching 1 Ampere could be extracted from this source through a 10 cm diameter gridded cathode at a discharge current of about 20 Amperesand a gas pressure of 0.5 micron. The cathode discharge current was found to contain electrons. The ion current to the reflector cathode is about 10% of the discharge current.     

Simulation,Design, Construction of Duoplasmatron and Diagnostic Neutral Beam System for Alborz Tokamak

Diagnostic Neutral Beam (DNB) has been used for measuring plasma parameters of tokamaks such as ion and electron temperature, safety factor, impurity concentration and etc. Ion source and electrical power supply specification are the main part of DNB. Arc discharge current value is affected by filament current and anode voltage. Beam current changes with arc current signal in our experiment that agree with theoretical relations. Sixty milli-ampere (60 mA) pulse beam current is because of arc current of about 40 A and extraction voltage of about 20 kV. The increase of beam current with arc current has been reported experimentally and effect of arc current on beam current has been investigated for several high extraction voltages. Optimum condition, which means having a telescopic beam (minimum divergence) for specific parameters of duoplasmatron, has been simulated and verified with experimental test. The best extraction voltage for these parameters has been found to be about 16-kV. The ratio of the perpendicular velocity to parallel velocity has been calculated to be about 0.012. It has been shown experimentally with optical emission spectroscopy that increase in arc current and magnetic current increase proton content of beam.     

HL-2AMW级中性束注入系统弧流电源设计

中性束注入是磁约束受控核聚变实验装置中加热等离子体最有效的方法之一。针对中国环流器2号中性束大功率离子源的特点,从系统功能、主电路拓扑结构、控制硬件及控制时序等方面对弧流电源进行设计。整个电源由低位移相交流调压、高压隔离降压变压器、整流滤波和电流快速转移电路4部分组成。IGBT与电阻串联组成电流快速转移阵列电路,与离子源并联,可实现电流单次或多次快速转移、参数远程设定,有效用于强流离子束的引出和保护。选用DSP和CPLD电路技术实现低位与高位控制器。实验数据显示,该电源最大输出为200kW/1000A,纹波小于2％,开关上升下降时间达μs级。目前,该电源已安全运行3年,可靠性高,完全满足装置离子源及系统要求,也可应用于其它等离子体技术应用场合。     

真空弧离子源脉冲工作瞬间的放电行为

采用高速摄影和光谱诊断的方法研究了真空弧离子源脉冲工作瞬间的放电行为。拍摄了离子源放电瞬间吸氢电极上阴极斑的形成过程，分析了不同放电电流时阴极斑的发射光谱。实验结果表明，当脉冲工作电流为10^1—10^2A时，真空弧离子源放电区一般只有单个阴极斑，阴极斑的位置在同一次放电中的变化很小；较大的脉冲工作电流有利于提高阴极斑的温度，并最终导致氢离子浓度的增加，但也会使阴极材料的溅射更加严重，造成离子源等离子体品质下降。     

A Source for Multiply-Charged Ions and Acceleration of C, N and O Ions by IPCR Cyclotron

The design and performance of the ion source which is now used in the IPCR variable energy cyclotron are described. The source is of the electron-bombarded hot cathode type having two cylindrical cathodes of tungsten and a water-cooled copper anode containing a replaceable molybdenum slit plate. The arc discharge is established continuously but not pulsed. The source is usually operated very stably under an arc power of 1.5 to 3kW with a gas flow rate of 1 to 2 cc/min. The lifetime of the source is mainly limited by the erosion of the upper tungsten cathode at about 24 hours. At present, C4+, N4+, O4+, N5+ and O5+ ions are accelerated up to 48~100, 56~1100, 70~95, 56~125 and 70~125 MeV respectively, and a few micro-amperes of these ions are extracted from the cyclotron. The vacuum obtainable in the accelerating chamber is usually 2 ~ 4 × 10-6 mHg, and the loss of ion beam by the charge exchange effect is comparatively small. Extracted ion beams are used in several experiments for about 1900 hours in a year.     

EAST强流离子源电源系统的初步测试运行

测试NBI大功率强流离子源的综合测试台正在建设,已研制了离子源等离子体发生器电源系统、等离子体电极高压电源及梯度极分压器、抑制极负高压电源等电源系统,以及高压传输线及缓冲器,在测试台上开展了对EAST中性束注入器第一台兆瓦级强流离子源样机进行整体电源系统测试和离子源起弧放电的初步测试,完成了离子源电源系统初步性能测试及...