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The Bennett ion‐mass spectrometer on Atmosphere Explorer‐C and ‐E
Author(s) -
Brinton H. C.,
Scott L. R.,
Pharo M. W.,
Coulson J. T.
Publication year - 1973
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs008i004p00323
Subject(s) - spectrum analyzer , ion , calibration , mass spectrometry , spectrometer , range (aeronautics) , physics , sensitivity (control systems) , time of flight , spectral line , body orifice , computational physics , analytical chemistry (journal) , optics , materials science , chemistry , ecology , chromatography , quantum mechanics , astronomy , electronic engineering , composite material , biology , engineering
The Bennett spectrometer to be flown on Atmosphere Explorer‐C and ‐E (AE‐C and AE‐E) is designed to measure, throughout the 120 to 4000‐km orbit, the concentrations of all thermal positive ions in the mass range 1 to 72 amu and number density range 5 to 5 × 10 6 ions cm −3 . To reduce the buildup of ram pressure and facilitate measurements at low altitude, the analyzer is vented, and a multigrid ion‐current collector is employed. An extensive command capability permits optimization of instrument parameters for particular measurement objectives; commandable functions include mass‐scan range and period, the sensitivity‐resolution characteristic of the analyzer, orifice potential, and in‐flight calibration. Any combination of three mass ranges (1 to 4, 2 to 18, 8 to 72 amu) may be selected as the mass‐scan mode; each range is normally scanned in 1.6 sec, corresponding to a distance of 12 km along the orbit. Ion spectra will be simultaneously telemetered in both analog and digital form; the digital data result from on‐board processing of the analog spectra and consist only of ion‐peak coordinates. The three overlapping mass ranges will enable in‐flight evaluation of mass discrimination within the ion analyzer. Verification of absolute instrument sensitivity will require correlation of the spectrometer data with results from the companion electrostatic probe and retarding‐potential analyzer. Such correlations should permit individual ion concentrations to be determined with an accuracy of ±10%.