不同金属带的非还原热离子发射特性

本文对在石墨存在下热电离质谱中常用且具有不同功函数的 Ta、Re、W、Pt四种金属带的 Cs2 Cl+和Cs2 BO2 +离子的非还原热离子发射特性进行了比较。研究结果表明 ,采用 Ta、Re、W、Pt四种金属带均能获得强的 Cs2 Cl+和 Cs2 BO2 +离子的发射 ,得到高精度的硼、氯同位素组成的测定。但是功函数较低的 Ta带的发射温度更低 ,测量精度更高 ,这表明在石墨存在下 Cs2 Cl+和 Cs2 BO2 +离子的发射与金属带的功函数无关

The Characteristics of Non-reductive Thermal Ion Emission of Filament Made of Various Materials

The characteristics of non-reductive thermal ion emission of Cs 2BO 2 + and Cs 2Cl + with graphite load, using four kinds of common ionization filaments Ta, Re, W and Pt having different work function, are compared in this paper. The results show that strong Cs 2BO 2 + and Cs 2Cl + ion beams, meanwhile high-precision isotopic measurement of boron and chlorine can be obtained by using Ta, Re, W and Pt filaments. The temperatures for emitting Cs 2BO 2 + and Cs 2Cl + ions using Ta filament with lower work function are lower and the precisions are higher. This result suggests that the emissions of Cs 2BO 2 + and Cs 2Cl + ions by loading graphite are not relative to the work function of the ionization filament. Ta and Re filaments are more suitable to isotopic measurement of boron and Ta and W filaments are more suitable to isotopic measurement of Chlorine. Meanwhile, the formation of oxidation layer on the surface of filament is favorable to obtain high precision isotope measurement of chlorine.