论文标题
开发具有高电离效率的电子冲击离子源为未来的行星任务开发
Development of an electron impact ion source with high ionization efficiency for future planetary missions
论文作者
论文摘要
使用电子撞击电离（EI）方法的离子源在质谱中已被广泛接受，用于行星勘探任务，因为它们的简单性。以前的太空源质谱仪主要是使用rhenium Tungsten合金丝的EI方法设计的，在典型情况下最多可实现200 UA的发射。希望增强发射水平，因为质谱仪的灵敏度是对未来与测量行星样品中痕量成分有关的原位质谱法的关键要求。在这项研究中，我们使用Y2O3涂层的虹膜丝开发了一种新的高发射EI离子源，该虹膜的功能比Rhenium Tungsten合金较低。离子源的大小为30 mm * 26毫米 * 70毫米，其重量为70 g。我们确认，当消耗3.0 W功率时，离子源会发出超过2 mA电子，这比以前的型号电子发射水平大10倍。 EI离子源的电离效率与电子发射量成正比，这意味着我们的新模型提高了电离效率10倍。我们对3.0 W加热条件的原型进行了性能测试，确认了高电离效率（10^4 na/pa）。此外，我们进行了离子源的耐力测试，并证明了30分钟 * 100循环的电离效率的持久性。
Ion sources using electron impact ionization (EI) methods have been widely accepted in mass spectrometry for planetary exploration missions because of their simplicity. Previous space-borne mass spectrometers were primarily designed with the EI method using rhenium tungsten alloy filaments, enabling up to 200 uA emission in typical cases. The emission level is desired to be enhanced because the sensitivity of mass spectrometers is a critical requirement for the future in situ mass spectrometry related to the measurement of trace components in planetary samples. In this study, we developed a new high-emission EI ion source using a Y2O3-coated iridium filament, which has a lower work function than rhenium tungsten alloy. The size of the ion source was 30 mm * 26 mm * 70 mm, and its weight was 70 g. We confirmed that when consuming 3.0 W power, the ion source emits more than 2 mA electrons, which is 10 times greater than the previous models electron emission level. Ionization efficiency of the EI ion source is proportional to the amount of electron emission, which implies our new model increased the ionization efficiency 10 times. We conducted performance tests on the prototype with the 3.0 W heating condition, confirming a high ionization efficiency (10^4 nA/Pa). In addition, we conducted endurance tests of the ion source and demonstrated the persistence of the ionization efficiency for 30 min * 100 cycles.
