MAGNETOSPHERIC ION COMPOSITION SPECTROMETER ONBOARD THE CRRES SPACECRAFT

The magnetospheric ion composition spectrometer (MICS) in the CRRES scientific payload utilizes time-of-flight and energy spectroscopy in combination with an electrostatic entrance filter to measure the mass A , energy E, and ionic charge Q of particles with energies between 1 keV/charge and 430 keV/charge. An advanced ogive design of the electrostatic filter system provides a narrow angle of acceptance and high sensitivity. Incident particles are postaccelerated prior to entering the detection segment in order to improve the resolution at the lower end of the useful energy range. The principle features of the MICS spectrometer are described in some detail. Selected data gathered in-flight are shown as an illustration of the instrument performance in the operational orbit.