New emissin spectrometers for multielement analysis with pulse operated plasma source and time-gated detector

为实现痕量元素分析，设计并建造了一种新型的微波等离子体源，它由几百瓦的短脉宽微波驱动，选择性地发射时间强度较高的原子线。它的显著特点是使用非冷却腔体，不需要重型同轴电缆。为了直接汽化固体材料和精确控制引入源的原子蒸气，安装了一个时间和空间稳定的火花源。调制的MIP和火花原子化器的结合非常有效地产生了简单而尖锐的原子线光谱，背景信号可以忽略不计，便于高精度的定量元素分析。针对脉冲操作等离子体源的时间分辨强度比测量等应用，对其线性和动态范围进行了详细的测量和理论分析。研制了一种新型的以射频脉冲氯化氢为激发源的时间门控原子荧光光谱仪，并对其进行了评价。发现了一种光子计数操作的峰面积检测模式，有效地扩展了元素分析的动态范围。

A new MIP source driven with several hundred-watt microwave of short duration, which selectively emitts temporally-intense atomic lines, was designed and constructed for allowing the trace element analysis. The use of non-cooled cavity and no requirement of heavy duty coaxial power cable are part of its notable features. For the direct vaporization of solid materials and precise control of the atom vapor introduction to the source, a tenporally and spacially stable spark source was attached. The combination of the modulated MIP and the spark atomizer was extreamely effective to yield simple and sharp atomic line spectra with a negligibly low back ground signal, facilitating quantitave element analysis with high precision.A miltichannel detection system using a gated silicon intensified target(SIT) vidicon was constructed for dynamic spectrophotometry. The linearity and dynamic range were carefully measured and theoretically analyzed for applications such as time-resolved intensity ratio measurements of pulse operated plasma sources.A new time-gated atomic fluorescence spectrometer with RF pulsed HCL as an excitation source was developed and evaluated for trace element analysis. A peak area detection mode of photon counting operation was found effective to extend the dynamic range of the element analysis.