A New Instrument for Thermal Electron Attachment at High Temperature: NF3 and CH3Cl Attachment Rate Constants up to 1100 K
Abstract
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: NF3 (300-900 K) and CH3Cl (600-1100 K). Electron attachment rate constants for NF3 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. CH3Cl attaches electrons too weakly to study with the low temperature FALP but reaches a value of ~10(exp -9) cu cm/s at 1100 K. F- is produced in NF3 attachment at all temperatures and Cl- in CH3Cl 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2009
- Accession Number
- ADA510246
Entities
People
- Albert A Viggiano
- Jeffrey F. Friedman
- John S. Williamson
- Linda C. Schaffer
- Thomas M Miller
Organizations
- Air Force Research Laboratory