Matter in the corona and solar wind is derived from the outer
convective zone (OCZ) of the Sun. Isotopic abundances of the
less volatile elements in the solar atmosphere are probably very
similar to terrestrial, lunar and meteoritic abundances. From
such elements it is possible to infer the amount of isotopic
fractionation under varying conditions in the solar wind source
region. For many species, the solar wind provides the only
source of information, which is important for many cosmochemical
and astrophysical applications. Knowledge of the isotopic
composition of the OCZ will yield information on the early solar
nebula and the history of the solar system. The CELIAS solar
wind mass spectrometer (MTOF, Mass Time-of-Flight sensor) has
unprecedented mass resolution for solar wind composition
studies, and has already measured rare elements and isotopes
that were previously not resolvable from more abundant
neighboring species, or were not previously observable at all.
The MTOF sensor is routinely measuring isot