Measurement of neutral atoms and ions in Mercury's exosphere

The Mercury apparatus for ions and atoms (MAIA) is a linear time-of-flight mass spectrometer operating in two modes, a neutral mode and an ion mode, w hich are used alternatively. MAIA is designed to determine the composition of Mercury's exosphere and possibly its crust. The mass resolution of MAIA is sufficient to resolve all elements up to mass 300 amu. In both optional modes the mass range extends from 1 to 100 amu, and, if required, it can be increased up to 300 amu by changing the data acquisition mode. Even isotop es could be resolved, however, the partial pressures at Mercury are most li kely too low for identification. (C) 2001 Elsevier Science Ltd. All rights reserved.