COSIMA (Cometary Secondary Ion Mass Analyser) is a secondary ion mass spectrometer equipped with a dust collector, a primary ion gun, and an optical microscope for target characterisation. Dust from the near comet environment is collected on a target. The target is then moved under a microscope where the positions of any dust particles are determined. The cometary dust particles are then bombarded with pulses of indium ions from the primary ion gun. The resulting secondary ions are then transferred into a mass spectrometer (time-of-flight mass spectrometer).
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