In this paper we consider the possibilities for producing a dense gas of N≃ 10 5 triplet
positronium (Ps) atoms in vacuum contained in small cavity V≃ 10− 13 cm 3. We then
consider the scenario where this dense gas of polarized Ps atoms may cool through a
weakly interacting Bose transition. The rates for thermalization with the wall, equilibrium in
the bulk, and loss of polarization by exchange collisions are calculated. A method for
observing the transition is also discussed.

… We suggest that a dense (n=10’8cm-3) gas of positronium (Ps) atoms will show ideal Bose
condensation. … In this paper we would like to suggest that a dense gas of positronium (Ps)
atoms is a good … Under our conditions we will be able to “see” the condensate with good
resolution, study the kinetics of the Bose condensation, understand in detail the size of then
Ps atom collision cross section and just possibly see some deviations from ideal behavior. …