RPC-ICA: The ion composition analyzer of the Rosetta Plasma Consortium

The Ion Composition Analyzer (ICA) is part of the Rosetta Plasma Consortium (RPC). ICA is designed to measure the three-dimensional distribution function of positive ions in order to study the interaction between the solar wind and cometary particles. The instrument has a mass resolution high enough to resolve the major species such as protons, helium, oxygen, molecular ions, and heavy ions characteristic of dusty plasma regions. ICA consists of an electrostatic acceptance angle filter, an electrostatic energy filter, and a magnetic momentum filter. Particles are detected using large diameter (100 min) microchannel plates and a two-dimensional anode system. ICA has its own processor for data reduction/compress ion and formatting. The energy range of the instrument is from 25 eV to 40 keV and an angular field-of-view of 360 degrees x 90 degrees is achieved through electrostatic deflection of incoming particles.