用于痕量分析的热腔离子源磁-电双聚焦同位素质谱计

摘要

A tube type thermal ionization cavity (TIC) ion source was developed and introduced into a self-made magnetic-electronic double focus mass spectrometer. High efficiency and low background was obtained by using ohmic heat and relatively independent control of sample evaporation and ionization. The evaluation measurements for trace analysis showed that the system detect efficiency for U and Pu was 1 % and 6% in average, the relative standard deviation of R235/233 for 50 pg natural uranium and R240/239 for 0. 1 pg plutonium (about 10 fg 240Pu contained) was less than 1% in the peak jump mode with one channel ion counting detector.%研制了一种管状热腔离子源并引入实验室自行研制的磁电双聚焦质谱系统中.离子源采用欧姆加热方式并可相对独立地控制样品蒸发和电离,因此在高效电离的同时保持了传统热表面电离质谱低本底特性.对该质谱系统痕量分析性能的初步测试表明:仪器对铀和钚的系统探测效率平均约为1％和6％；在跳峰计数法丰度比测试模式下,50 pg天然铀标样R235/238和0.1 pg钚标样(240P含量约10 fg)R2240-239的同位素分析的相对标准偏差小于1％.