General Antiparticle Spectrometer (GAPS) is a planned experiment that will utilize a high-altitude balloon flying in Antarctica to look for antideuteron particles from outer space cosmic rays, in an effort to search for dark matter. Anti-deuterons can be produced by the annihilation of hypothetical weakly interacting massive particles (WIMPs). The goal of the GAPS experiment is to captured anti-deuterons in a target material, to form an exotic atom in an excited state. The exotic atom would quickly decay, producing detectable X-rays energies with pion signature from nuclear annihilation.
The GAPS ground test was successfully using an particle accelerator at KEK in 2004 and 2005. The first high-altitude balloon test was done in June 2012 with six Si(Li) detectors.