负载线圈功率和采样锥孔径对ICP离子源特性影响模拟研究

SIMULATION INVESTIGATION ON THE INFLUENCE OF LOAD COIL POWER AND SAMPLING CONE APERTURE ON THE CHARACTERISTICS OF ICP ION SOURCE

文章基于三管嵌套式轴对称主流ICP炬管结构模型,模拟研究了负载线圈功率和采样锥孔径对ICP气体温度分布和流场特性的影响。研究结果表明:(1)增加负载功率能够提高ICP高温核心区的气体温度,但超过一定阈值后负载功率对中心通道上的气体温度无明显影响;(2)采样锥孔径扩大将导致负载功率难以输送到中心通道上,负载功率较高,中心通道的高温区段部分(气体温度大于6000K)会变窄;负载功率较低,则锥前气体温度会出现明显下降,而且采样锥孔径扩大后有利于分析易于扩散的元素离子;(3)极低的负载功率或过大的采样锥孔径在中心气流和辅助气流的流动交界面造成微小扰动,但通过适当提高负载功率可以有效消除这些扰动。研究结果可为优化ICP工作参数以及设计新的离子源接口装置提供一定的理论指导。

Basing on three tube nested axis symmetric mainstream inductively coupled plasma（ICP）torch tube model,we study the effects of load coil power and sampler orifice diameter on gas temperature and flow field of ICP.Results show that：1）Increase of the load coil power can raise gas temperature of core area of inductively coupled plasma when the load coil power is lower than threshold power,but the load coil power can hardly have an impact on gas temperature of plasma center channel when it is higher than the threshold power.2）Sampler orifice with enlarged diameter will make it harder to transfer the load coil power to center channel.If load coil power is a little higher,the length of center channel with gas temperature higher than 6000 K will be contracted,but if not,the gas temperature before sampler orifice will drop down obviously.Otherwise,larger orifice diameter is supposed to be very useful for the analysis of elements,whose ions are easy to diffuse.3）Both extremely low load coil power and enlarged orifice diameter can cause infinitesimal disturbance on the interface between injector central gas and auxiliary gas.Appropriately improved load coil power can efficiently eliminate the disturbance.This work can help optimize the working parameters of ICP and provide theoretical references for the design of new ICP interface device of ion source.