强短脉冲供电时空心阴极灯的放电特性研究

Characteristics of a High Current Microsecond Pulsed Hollow Cathode Lamp

空心阴极灯是原子光谱分析中常用的线光源。对它的光谱和放电特性的研究已有报道,但多为针对直流供电或一般脉冲供电状态时的空心阴极灯。黄本立等报道了市售空心阴极灯在强短脉冲供电时的时间分辩光谱特性及其作为高强度离子线或原子线光源的可行性。本文通过对Eu空心阴极灯在强短脉冲供电时的伏安特性,以及对直流和强短脉冲供电时空心阴极灯发射光谱差异的研究,探讨了强短脉冲供电时空心阴极灯的放电机制,讨论了离子线和原子线强度增强的过程。 1 实验部分 1.1 仪器 1.0m平面光栅光谱仪(中国科学院长春应用化学研究所),光栅刻线1200条/mm,入射和出射狭缝宽度分别为10和35μm,一级光谱倒色散率0.8nm/mm;MF-1A型脉冲发生器(南通电子仪器厂);自制HCL供电电源和Boxcar积分器;BS-5504型双踪示波器(40 MHz,韩国安罗);瞬态记录仪频率为20 MHz(中国科技大学快电子学实验室),1P28A和EMI 6265型PMT;LM-15型X-Y记录仪;所用HCL为市售商品灯。 1.2 实验装置 研究空心阴极灯(HCL)光谱特性的装置见图1.由脉冲发生器产生的脉冲信号通过灯电源控制HCL,由HCL发射的光经单色仪后由光电倍增管(PMT)将光信号转化为电信号,经前置放大器以及Boxcar积分器或瞬态记录仪后采集并记录脉冲信号。图1中PG为脉冲发生器,HCL

The voltage-current and spectral characteristics of a high current (up to tens of amperes)microsecond pulsed hollow cathode lamp has been studied. The intensities of the atomic and ionic lines emitted by the pulsed HCL are greatly enhanced as compared with those emitted by the same lamp with DC supply, and the enhancement factor is much greater for the ionic lines (104) than for the atomic lines. This implies that the HCMSP HCL could be used as a convenient and inexpensive source for ionic fluorescence spectrometry.