Parallel-Plate Energy Analyzer
An electrostatic diagnostic that determines ion energy distribution and examines ion energy properties.
Figure 1. Schematic of the parallel-plate energy analyzer.
Figure 2. Photograph of PEPL's parallel-plate energy analyzer with cover removed (from ref. 2).
A parallel-plate type electrostatic energy analyzer consists of two parallel plates separated by a distance d.
One of the plates is electrically grounded while the other is biased to a positive potential, Vr.
Ions enter through a sampling orifice and transit through a drift tube before entering the section composed of the two charged plates.
The electrostatic field between these plates causes the ion trajectories to curve in a parabola.
At the output of the analyzer is a slit that leads to a detector.
Due to the geometry of the system, only ions with a specific energy-to-charge ratio will reach the detector.
By varying the field between the charged plates, the entire spectrum of ion energies can be measured.
However, while a doubly charged ion will be accelerated to twice the kinetic energy of a singly charged ion, they will have the same energy-to-charge ratio.
In order to examine the difference between these states, it is necessary to use a second instrument, a Time of Flight Mass Spectrometer (TOF).
Selected Relevant Publications
Beal, B. E., "Clustering of Hall Effect Thrusters for High-Power Electric Propulsion Applications,"
Ph.D. Dissertation, University of Michigan, 2004.
Walker, M. L. R., "Effects of Facility Backpressure on the Performance and Plume of a Hall Thruster,"
Ph.D. Dissertation, University of Michigan, 2005.