The Nuclear and Ionic Charge Distribution Particle Experiments on the ISEE-1 and ISEE-C Spacecraft

The ISEE-1 and ISEE-C instruments have been designed to measure the elemental abundances, charge state composition, energy spectra, and angular distributions of energetic ions in the energy range 2 keV/charge to 80 MeV/nucleon and of electrons between 75 and 1300 keV. By covering the energy range between solar wind and low-energy cosmic rays the instrument will fill a gap in the knowledge especially of the nuclear and ionic composition of solar, interplanetary, and magnetospheric accelerated and trapped particles. The instrument consists of three different sensor systems: ULECA is an electrostatic deflection analyzer system with rectangular solid-state detectors as energy determining devices, its energy range is ~3 to 560 keV/charge; the ULEWAT is a double dE/dX versus E thin-window flow-through proportional counter/solid-state detector telescope covering the energy range from 0.2 to 80 MeV/nucleon (Fe); the ULEZEQ sensor consists of a combination of an electrostatic deflection analyzer and a thin-window dE/dX versus E system with a thin-window proportional counter and a positionsensitive solid-state detector. The energy range is 0.4 MeV/nucleon to 6 MeV/nucleon. While the ULECA and the ULEWAT sensors are designed mainly for interplanetary and outer magnetospheric studies, the ULEZEQ sensor will also obtain composition data in the trapped radiation zone. 65 rates and pulse-height data can be obtained with sectoring in up to 16 sectors.