The Mass-Separating Ion Spectrometer on the AMPTE Ion-Release Module

Mass-Separating Ion Spectrometer (MSIS) flown on the Ion Release Module of the AMPTE Mission was derived from a similar instrument (MASSWE) proposed and accepted for the United States spacecraft of the International Solar Polar Mission (Ulysses). It features an energy-per-charge range of 0.5 V to 14 kV, two separate systems for particle detection, each with a field of view of approximately 3° X 36°, and is distinguished from previously flown instruments by imaging capabilities in mass per charge which are employed for simultaneously detecting the ion species H+, 4He2+, 16O6+, 4He+, (7Li+; 56Fel0+; 56Fe8+), (16O2+; 56Fe7+; 56Fe6+), 16O+, (3He2+, or 137Ba+). Three different measurement modes make possible the adaption to low-energy particle measurements in an ion-release cloud, solar-wind investigations, and magnetospheric plasma measurements.