An improved spherical energy analyzer (a type of electrostatic mass spectrometer) is under development for use in analyzing a beam of ions generated by a Hall thruster. The major improvement, relative to a commercial spherical energy analyzer, is the addition of a quadrupole stage (with refocusing electron optics) for separating ions of different charge states. The development work also includes efforts to make the instrument smaller and lighter than the commercial version in order to make it possible to translate and rotate the instrument through the ion beam inside a vacuum chamber that contains the Hall thruster.

This work was done by Dennis Fitzgerald and James Cooley of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tspunder the Physical Sciences category.

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