Strategy of intense ion beam accumulation by use of charge exchange injection

Accumulation of ions in a storage ring using charge exchange injection give s the possibility of storing the ion beam with parameters applicable to pla sma experiments. Beam quality on the target can be defined by the factor of beam quality K-b = 1.5Pa, where P is specific power, and a is beam radius. A simple formula, which allows one to estimate the value of K-b, for arbitr ary accelerator parameters, is derived. This formula shows that in the abse nce of an electron cooling system (ECS) the main limitations appear due to intra beam scattering, increasing momentum spread of the stored beam. A mor e accurate analysis for ITEP-TWAC project is made by use of Monte-Carlo cod e. Four different storage scenarios are considered: fast scenarios with hig h intensity of injected beam and comparatively short accumulation time (10- 20 injection cycles); slow scenarios with long accumulation time (100-200 i njected cycles) (for both cases options with and without ECS have been cons idered). For all options, central injection scheme is used, where charge ex change target coincides with the center of the coasting beam. By optimizati on of the factor K-b the optimal parameters (number of injections, intensit y, emittance, momentum spread) have been calculated for each scenario. (C) 2001 Elsevier Science B.V. All rights reserved.