First positron cooling of antiprotons

Positrons are used to cool antiprotons for the first time. The oppositely c harged positrons and antiprotons are first simultaneously accumulated in se parate Penning trap volumes, and then are spatially merged in a nested Penn ing trap. The antiprotons cool until they reach a low relative velocity wit h respect to the cold positrons, the situation expected to be optimal for t he production of cold antihydrogen. (C) 2001 Published by Elsevier Science B.V.