CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF PHYSICS
We present a calculation of the imaginary part of the self energy Sigma sub 1 of a positron in an electron gas. Sigma sub 1 is inversely proportional to the inelastic collision rate between the positron and the electron gas. The calculation was done using standard many body techniques and within the RPA approximation. There are two contributions to Sigma sub 1 one arising from particle-hole pair excitation, the other from plasmon excitation.