Miller Thomas M, Friedman Jeffrey F, Williamson John S, Schaffer Linda C, Viggiano A A
Air Force Research Laboratory, Space Vehicles Directorate, 29 Randolph Road, Hanscom Air Force Base, Massachusetts 01731-3010, USA.
Rev Sci Instrum. 2009 Mar;80(3):034104. doi: 10.1063/1.3097185.
A new high temperature flowing afterglow Langmuir probe (HT-FALP) apparatus is described. A movable Langmuir probe and a four-needle reactant gas inlet were fitted to an existing high temperature flowing afterglow apparatus. The instrument is suitable for study of electron attachment from 300-1200 K, the upper limit set to avoid softening of the quartz flow tube. We present results for two reactions over extended ranges: NF(3) (300-900 K) and CH(3)Cl (600-1100 K). Electron attachment rate constants for NF(3) had been measured earlier using our conventional FALP apparatus. Those measurements were repeated with the FALP and then extended to 900 K with the HT-FALP. CH(3)Cl attaches electrons too weakly to study with the low temperature FALP but reaches a value of approximately 10(-9) cm(3) s(-1) at 1100 K. F(-) is produced in NF(3) attachment at all temperatures and Cl(-) in CH(3)Cl attachment, as determined by a quadrupole mass spectrometer at the end of the flow tube. Future modifications to increase the plasma density should allow study of electron-ion recombination at high temperatures.
介绍了一种新型高温流动余辉朗缪尔探针（HT-FALP）装置。在现有的高温流动余辉装置上安装了一个可移动的朗缪尔探针和一个四针反应气体入口。该仪器适用于研究300至1200K的电子附着过程，设定上限是为了避免石英流管软化。我们给出了两个反应在扩展温度范围内的结果：NF(3)（300至900K）和CH(3)Cl（600至1100K）。NF(3)的电子附着速率常数此前已使用我们传统的FALP装置进行了测量。用FALP重复了这些测量，然后用HT-FALP将其扩展到900K。CH(3)Cl对电子的附着太弱，无法用低温FALP进行研究，但在1100K时达到约10(-9) cm(3) s(-1)的值。通过流管末端的四极质谱仪确定，在NF(3)附着过程中所有温度下都会产生F(-)，在CH(3)Cl附着过程中会产生Cl(-)。未来为提高等离子体密度而进行的改进应能实现对高温下电子-离子复合的研究。
