2.0.0 spase://SMWG/Instrument/AE-C/BIMS Bennett Ion-Mass Spectrometer (BIMS) BIMS 2019-05-05T12:34:56Z This experiment was flown to measure, throughout the AE-C orbit, the individual concentrations of all thermal ion species in the mass range of 1 to 72 atomic mass units (u), and in the ambient density range from 8.E1 to 5.E6 ions/cc. Any combination of the following three mass ranges, expressed in u, were selected by ground command: range A, -1 to 4, range B, -2 to 18, range C, -8 to 72. Each range was normally scanned in 1.7 s (approximately 12 km along orbit). Normal operation consisted in sequence ABCABC (1 to 72 u in 5.1 s). Laboratory and inflight determination of spectrometer efficiency and mass discrimination permitted direct conversion of measured ion currents to ambient concentrations. The experiment's four primary mechanical components were guard ring and ion-analyzer tube, collector and preamplifier assembly, vent, and main electronics housing. The guard ring was normally at ground potential, but it could be placed at -6 V by command if desirable, e.g., if the spacecraft acquired a positive charge. A three-stage Bennett tube with 7 to 5 cycle drift spaces was flown and was modified to permit ion concentration measurements to be obtained at low altitudes. The frequency of the 30 V peak-to-peak RF voltage varied with the mass range measured: range A, -10 MHz, range B, -5 MHz, and range C, -2.5 MHz. Primary analog instrument output was a compressed ion current spectrum which displayed the full dynamic range of the amplifier system on a single telemetry channel. Onboard data processing provided a readout of primary experiment data in the form of two digital words for each peak in the ion spectrum. One 8-bit word indicated peak amplitude (current) and the other 8-bit word identified sweep position, i.e., species identification. More complete details can be found in H. C. Brinton et al., Radio Sci., v. 8, n. 4, p. 323, 1973. NSSDC has all the useful data that exist from this investigation. spase://SMWG/Person/Henry.C.Brinton PrincipalInvestigator NSSDC's Master Catalog https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1975-107A-10 Information about the Bennett Ion-Mass Spectrometer (BIMS) experiment on the AE-C mission. Radio Science Journal Article https://onlinelibrary.wiley.com/doi/abs/10.1029/RS008i004p00323 Detailed information about the Bennett Ion-Mass Spectrometer (BIMS) on the AE-C mission. MassSpectrometer Bennett Ion-Mass Spectrometer (BIMS) on AE-C spase://SMWG/Observatory/AE-C