Time‐resolved mass and energy analysis by position‐sensitive time‐of‐flight detection

• Published in: Review of Scientific Instruments 1990-10, Vol.61 (10), p.3134-3136
• Main Authors: Pollard, J. E., Lichtin, D. A., Janson, S. W., Cohen, R. B.
• Format: Article
• Language: English
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 700102 - Fusion Energy- Plasma Research- Diagnostics; ELECTRON MULTIPLIER DETECTORS; ENERGY RESOLUTION; Exact sciences and technology; ION DRIFT; MASS SPECTROMETERS; MEASURING INSTRUMENTS; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges; PLASMA DIAGNOSTICS; POSITION SENSITIVE DETECTORS; RADIATION DETECTORS; RESOLUTION; SPECTROMETERS; TIME-OF-FLIGHT SPECTROMETERS
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1141705

We describe a method for time‐resolved mass and kinetic energy analysis of ionic or neutral species (1–150 amu, 0.5–500 eV) in diagnostic measurements on spacecraft electric thrusters. Time‐of‐flight mass spectrometry is combined with position‐sensitive detection to measure energy spectra for multiple masses at sampling rates as high as 50 kHz. A rectangular microchannel plate detector with a 96‐element metal anode array is read out by fast analog‐to‐digital converters or by discriminators and scalers. The ion drift time varies as the square root of the mass‐to‐charge ratio, and the displacement along the detector varies as the square root of the energy‐to‐charge ratio. The energy resolution is enhanced by minimizing the field distortion near grid wires.