The heavy ion analyser PICCA for the Comet Halley fly-by with Giotto

Abstract

The heavy ion analyser RPA2-PICCA is designed to identify the composition and distribution of thermal positive ions in the coma of Comet Halley. The instrument is an electrostatic analyser which takes advantage of the large relative fly-by velocity and the fact that the ions in the inner coma should have low temperatures and be predominantly singly charged. Thus the E/Q (energy/charge) measurements can be directly related to the mass distribution of the ions. Mass identification will be provided in the range from 10 to 203 amu (atomic mass units) with a mass resolution of either Delta m=0.4 amu or Delta m=1 amu dependent on the ion mass.