LIF Velocity Measurement of Sputtered Boron Atoms from Boron Nitride Target

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83624/1/AIAA-2010-6526-898.pd

Influence of Discharge Oscillation on Hall Thruster Performance *

Influence of discharge oscillations at frequency range of 10-100kHz was investigated using the 1kW class sheath type Hall thruster. Lifetime, that is, wall erosion was examined by means of spectroscopy. The erosion rate in unstable operation was twice as large as that in stable operation. Plume divergence was also measured. The full angle at half maximum of thruster plume was increased from 14.4 to 18.2 degree when the operation was changed from stable operation to unstable operation. However, the oscillation amplitude had little relation with the erosion rate, the plume divergence and the thruster performance. These results would indicate that the ionization zone configuration would affect lifetime, the plume divergence, thruster performance and oscillation rather than oscillation in itself would affect lifetime, the plume divergence and thruster performance

High-Sensitivity Boron Nitride Sputter Erosion Measurements by Continuous-Wave Cavity Ring-Down Spectroscopy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77100/1/AIAA-2008-5091-176.pd

Boron Nitride Sputter Erosion Measurements by Cavity Ring-Down Spectroscopy

Abstract: Sputter erosion is a critically important process in many electric propulsion (EP) devices from the point of view of both lifetime assessment and contamination effects. In many Hall thrusters erosion of boron nitride (BN) is of primary interest. In this contribution we introduce the use of cavity ring-down spectroscopy (CRDS) as a diagnostic for measurement of sputtered BN. The measurement approach is based upon probing sputtered boron atoms in the region of 250 nm. We report proof of principle CRDS measurements of sputtered boron atoms from both boron and BN targets. The measurements are obtained with pulsed CRDS in a diagnostic chamber consisting of an ion beam incident on the target materials. We also outline the design of a higher sensitivity continuous-wave (cw) CRDS system using the fourth harmonic beam from an external cavity diode laser as the light source. The cw-CRDS system will be used for near real time sputter erosion measurements of thruster devices. Anticipated signal levels and signal-to-noise for the cw-CRDS system are discussed. Nomenclatur

アノードレイヤ型ホールスラスタの作動特性

Thrust performance and stable operation conditions of an anode layer type Hall thruster was investigated using a 1.5kW class anode layer type Hall thruster. The thrust efficiency reached at 53% with the specific impulse of 2,000s, which are competitive with these of SPT-100 thrusters. Anode shape and axial position of the anode were changed. Stability of the discharge was found sensitive to the anode configuration and applied magnetic flux density