Obtaining velocity distribution using a xenon ion line with unknown hyperfine constants
We present and validate a method for extracting velocity distribution functions from laser-induced fluorescence measurements obtained using a xenon ion line with unknown hyperfine constants. The method involves a direct deconvolution of intermodulated experimental results from the laser-induced fluorescence measurements. The intermodulated experiments were done on the 5d[4]7/2 → 6p[3]°5/2 transition for singly-charged xenon at 834.7 nm. The hyperfine constants for this line are large enough to distort the results but small enough to have eluded accurate measurement. This approach is validated using both simulated results and a set of measurements taken in a Hall thruster environment. The validity of the method is scrutinized through the uncertainty analysis that follows. The method was determined to contribute at most ±0.1% to the absolute uncertainty of the velocities and at most a 4% decrease to the full-width-at-half-maximum of the velocity distribution functions measured in the accelerating plasma of the Hall thruster. Copyright © 2009 by Wensheng Huang.
