  The Alpha Magnetic Spectrometer (AMS), whose final version AMS-02 is to be
installed on the International Space Station (ISS) for at least 3 years, is a
detector designed to measure charged cosmic ray spectra with energies up to the
TeV region and with high energy photon detection capability up to a few hundred
GeV, using state-of-the art particle identification techniques. Among several
detector subsystems, AMS includes a proximity focusing RICH enabling precise
measurements of particle electric charge and velocity. The combination of both
these measurements together with the particle rigidity measured on the silicon
tracker endows a reliable measurement of the particle mass. The main topics of
the AMS-02 physics program include detailed measurements of the nuclear
component of the cosmic-ray spectrum and the search for indirect signatures of
dark matter. Mass separation of singly charged particles, and in particular the
separation of deuterons and antideuterons from massive backgrounds of protons
and antiprotons respectively, is essential in this context. Detailed Monte
Carlo simulations of AMS-02 have been used to evaluate the detector's
performance for mass separation at different energies. The obtained results and
physics prospects are presented.
