Study of the quenched lifetime of an interacting positronium gas

By using a kinetic approach, we study the evolution of a gas composed of interacting ortho- and para-positronium atoms. We calculate the total lifetime of the gas and study the orthopositronium quenching effect induced by the bi-atomic scattering mechanisms with spin exchange. We analyze a realistic situation where the positronium is formed by highly energetic positrons impinging on a solid surface. In the case of a spin-polarized source of positrons, the spinpolarization time of the final positronium gas is estimated.