This work discusses the prospects of antiparticle flux measurements with the proposed PEBS detector. The project foresees long duration balloon flights at one of Earths poles at an altitude of 40 km. The sky coverage of flights at the poles is presen
ted. In addition, cosmic-ray measurements at the poles (small rigidity cut-offs) give the possibility to study solar modulation effects down to energies of about 0.1 GeV. Furthermore, systematic effects due to interactions of cosmic rays in the atmosphere are important. These effects were studied with the Planetocosmics simulation software based on GEANT4 in the energy range 0.1 - 1000 GeV.
