Detection of primordial antimatter at the 10−7 level

Abstract In order to search for cosmic antimatter at the 10 −7 level, a new instrument, combining a counter system with scintillation fiber imaging is under development for Antarctica balloon flights. The counter system selects candidates of antimatter at 10 −5 sensitivities as confirmed by an experiment using accelerator antiproton beams. The candidate events selected by the counter system will be identified by topological methods with scintillation fiber imaging. One Antarctica balloon flight will reach flux sensitivities of around the 10 −7 level for antiprotons as well as antihelium and heavier antinuclei.