Top hat electrostatic analyzer for far-field electric propulsion plume diagnostics

The design, development, and testing of the top hat electric propulsion plume analyzer (TOPAZ) are presented for far-field electric propulsion plume diagnostics. The trend towards high-power thruster development will require plume diagnostic techniques capable of measuring high-energy particles as well as low-energy ions produced from charge-exchange collisions due to elevated facility background pressures. TOPAZ incorporates a “top hat” design with a geometrical analyzer constant of 100 resulting in a wide energy range and a high-energy resolution. SIMION, an ion trajectory analysis program, was used to predict characteristics of the analyzer. An ion beam accelerator system confirms the computational results. TOPAZ provides an energy resolution of 2.7%, field of view of $112°×26°$ (azimuthal by elevation) with an angular resolution in each direction of 2°, and a demonstrated energy-per-charge acceptance range of $5–15keV$⁠. An energy profile measurement of the NASA-173Mv1 Hall thruster demonstrates instrument operation in a Hall thruster plume.