[en] The injection channel region of high current beam from injector up to buncher has been computed. The beam dynamics is considered by the momentum procedure as well as by effective linearizing of spatial charge forces. The channel dimensions optimization under the routine of dialogue ''Man-Machine'' and optimization by the FUMILI program has been held. The effects stipulated by spatial charge non-linearity are considered for selected variant in the super-macro particle model. The chosen dimensions of the channel elements provide the beam transport with different distributions without losses