Charge exchange collisions in the presence of competing processes: an integral equation approach

Abstract

The neutral fraction and spin depolarisation of positively charged particles during charge exchange have been investigated theoretically without simulations. In the charge exchange regime, both positive and neutral charge states contribute to the energy loss of the particle and the final product after thermalisation is determined by the competition between the charge exchange process and other energy-loss mechanisms. Integral equations for the neutral fraction and spin polarisation are expressed directly in terms of the cross sections of the atomic processes contributing to the slowing down of the particles. The integral equations for the positive muon in Ne have been solved self-consistently, where the cross section for the charge exchange, elastic and ionisation processes for positive as well as neutral species (muon and muonium, respectively) are obtained from the corresponding proton and hydrogen data by simple scaling schemes.