Nonlinear distortion of multicomponent heavy ion beam emittance caused by space charge fields

The beam of 48Ca ions is obtained in an electron cyclotron resonance (ECR)-ion source with helium as plasma supporting gas. The current of helium ions is often greater than the calcium one. The influence of the helium ions self-fields on emittance of calcium beam during the common transportation from the ECR-ion source to analyzing bending magnet is investigated by macroparticles simulation. For a large magnitude of helium space charge, the calcium ions have a holed-beam shape after analyzing magnet and beam emittance strongly increased. The possibilities of elimination of this effect are discussed