  A measurement of the cosmic ray positron fraction e+/(e+ + e-) in the energy
range of 1-30 GeV is presented. The measurement is based on data taken by the
AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton
background suppression on the order of 10^6 is reached by identifying converted
bremsstrahlung photons emitted from positrons.
