Two-stage Rydberg charge exchange: An efficient method for production of antihydrogen

An efficient method for production of cold antihydrogen ((H) over bar) is proposed. Alkali-metal atoms laser excited to a Rydberg state are charge exchanged with cold trapped positrons, producing Rydberg states of positronium. In a second Rydberg-state charge exchange, the positronium atoms give up their Rydberg positrons to cold trapped antiprotons, producing Rydberg stares of (H) over bar. These (H) over bar atoms soon decay down to the ground state, and, because they are cold, could be trapped in a magnetic trap. The efficiency of the process results from the extremely large cross sections for Rydberg charge exchange. Classical trajectory Monte Carlo calculations indicate an (H) over bar instantaneous production rate of 10-6/S.