ANTIPROTON ANNIHILATION ON NUCLEI AT INTERMEDIATE ENERGIES RESULTING FROM ONE, 2 AND AN INFINITE NUMBER OF COLLISIONS

Antiproton annihilation cross sections on nuclei from Ne-20 to Pb-208 are calculated in the framework of a microscopic optical model in the kinetic energy range E(L) = 50 - 2000 MeV both directly in the initial channel and after single quasi-free collision. The part of annihilati on yield after one quasi-free nucleon knock-out from the nucleus in 20 -25% of the contribution to the annihilation cross section in the init ial channel. The sensitivity of this cross section to the parameters o f antinucleon-nucleon scattering amplitude is investigated. Calculated ratios of volume to surface annihilation cross sections are compared with experimental ones.