Indirect Dark Matter Search: Cosmic Positron Fraction Measurement from 1 to 50 GeV with AMS-01

A new measurement of the cosmic ray positron fraction in the energy range of 1-50 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 in the order of 10^6 is reached by identifying converted bremsstrahlung photons emitted from electrons and positrons.