Electrostatic Energy Analyzer (ESA): Determines fraction of multiply charged ions and ion energy distribution.

An ESA has been developed at PEPL.  The ESA uses two instruments to conduct its measurements:  a 45-degree, Parallel-Plate Energy Analyzer and a TOF.   The parallel plate section of the ESA acts as a velocity per charge filter for a given ion species since only ions of a specific energy-to-charge ratio are collected.  An extension has been machined to allow this device to be used as a time of flight mass spectrometer.  The mass to charge ratios of plume ions can be determined by using the fact that ions of different charge but equal mass are accelerated to different velocities by a given potential drop. The fraction of multiply charged ions can be determined.

1.   Beal, B. E., and Gallimore, A. D., “Energy Analysis of a Hall Thruster Cluster,” IEPC-03-035, 29th    International Electric Propulsion Conference, Toulouse, France, March 17-20, 2003.