Monte Carlo Study of Ortho-Positronium Laser Cooling

抄録

On the basis of three dimensional (3-D) Monte Carlo simulation, we studied details of laser cooling (Doppler cooling) of ortho-Positronium (o-Ps) which would be applied to the achievement of Bose-Einstein condensation of positronium. The cooling is carried out by an ultraviolet laser with a wavelength of 243 nm being equivalent to the 1S-2P transition energy of o-Ps. For this purpose, we have constructed a laser cooling apparatus which consists of a slow positron generator and a long pulse, wide linewidth laser. A 3-D Monte Carlo calculation, which incorporated various parameters of laser beam and positronium distributions expected in the current laser cooling apparatus, revealed that 7% of o-Ps was able to be cool down to 1 K and to be confined in a relatively small volume without employing a special trap.