Development of a positron trap for the laser cooling experiment of positronium

A cloud of ortho-positronium produced at the room temperature can be cooled down to 0.6 K utilizing a long pulse 180 ns. laser with 243 nm wavelength. We developed a time bunching system of a slow positron beam to synchronize production of positronium atoms to the laser pulse. After a theoretical examination using a Monte Carlo simulation, an experiment was made for confirmation. q1999 Published by Elsevier Science B.V. All rights reserved.