ION MOLECULE REACTIONS IN A 50 MEGACYCLE DISCHARGE.
PURDUE UNIV LAFAYETTE IND PROJECT SQUID HEADQUARTERS
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Studies of ions arriving at the orifice of a sampling probe from a plasma produced by an electrodeless discharge were made primarily by the use of a quadrupole mass spectrometer. Extensive investigation of the dependence of the relative ion intensities on the discharge conditions particularly the pressure and of the relative ionic composition as a function of the energy of the ions issuing from the orifice of the sampling probe were made. The results indicate that the ions collected and observed are formed in a narrow region in front of the probe orifice and that these ions gain most of their energy from the electric field of the sheath in a distance that is much less than a reaction mean free path. The collected and observed ions were found to originate in a distance of approximately one millimeter from the probe orifice. The average reaction time was found to be a few tenths of a microsecond and independent of the vessel geometry and dimensions. The average reaction time was relatively insensitive to changes in pressure. They were found to be reasonably constant for ions in several different gases and an attempt was made to relate them to the mean electron energy and the electron density. The observed reaction rate constants in the plasma were in reasonable agreement with those reported from electron impact sources. Author
- Atmospheric Physics
- Physical Chemistry
- Plasma Physics and Magnetohydrodynamics