Sensitivity of positron transport and annihilation to elastic scattering across the noble gases

Abstract We present a systematic investigation of the sensitivity of positron transport and annihilation to variations in elastic scattering phase shifts across the noble gases (He-Rn). Using a time-dependent Boltzmann equation solver, we compute the evolution of the effective annihilation parameter ⟨Zeff ⟩ during thermalization for cross sections derived from perturbed phase shifts. We demonstrate that the strong sensitivity previously observed in xenon persists across the noble gas series. We find that the total elastic scattering cross section provides rather modest constraints, whereas annihilation measurements provide significantly stronger constraints on the allowable scattering phase shifts. These results highlight the complementary role of transport, scattering and effective annihilation experiments in determining positron-atom interactions.