Ion beamlet divergence characteristics of two-grid multiple-hole ion-accelerator systems

An experimental investigation was performed to determine the divergence cha racteristics (distortion factor, divergence angle, and divergence factor) o f ion beamlets that were commonly formed using multiple-hole, ion-accelerat or systems of ion thrusters. An isolated ion beamlet was observed three dim ensionally using arrayed Faraday probes, and its divergence characteristics were determined as a function of geometrical grid parameters and grid volt ages. Because xenon was used as a propellant and the grid voltages were cho sen being conscious of a recent ion-thruster technology trend, the results can be used for designing ion thrusters by simply translating geometrical g rid parameters. The results did not contradict those in previous studies th at used argon and one- or two-dimensional beam diagnostics.