A molcular beam mass spectrometer for hall thruster plume studies: Preliminary data
The motivation behind the construction of a Molecular Beam Mass Spectrometer (MBMS) for transport property measurements in Hall thruster plumes is presented. This system utilizes a set of orifice plates to skim off a small beam of plasma from the plume of a Hall thruster. This beam is collimated and energy filtered using a 45 degree parallel plate electrostatic energy analyzer. Data of a preliminary nature is presented including high-resolution ion energy distribution curves of Xe+ propellant in the plume of an SPT-100. These data show a higher than expected most probable energy that is very near the thruster discharge voltage. In addition, the distributions indicate the presence of a high energy “tail” of ions with energies greater than the thruster discharge voltage.
