Shulga D. Forming of high brightness ion beams in helicon sources

The dissertation is devoted to a problem of production of ion beams with high paraxial brightness to increase resolution of facilities with focused ion beams, and production of high-current beams for application in neutron generators based on the electrostatic accelerator. Measurements of the beam mass structure shown, that proton percentage is 80 % of the general beam structure. Energy spread of helium and hydrogen ion beams is less than 30 eV. In an operating mode of helicon ion source with a non-uniform magnetic field at Р=200 W, current density of helium beam reaches j=120 mA/cm2. Calculations of the ion beam phase portrait in plane of the exit aperture with diameter of 1,5-mm and 1-mm were performed. Differential brightness of 65 А/m2rad2eV and 95 А/m2rad2eV were obtained experimentally after beam passing through the exit aperture with diameter of 1,5 mm and 1mm, respectively. High-current extraction system permitting to obtain current strength of 4 mА for hydrogen ion beams, 4,5 mА for helium ion beams at 350 W RF power and current density of a proton beam 127 mА/сm2 was designed and constructed. High brightness extraction system with the metal extraction aperture separated from plasma electrode by insulating quartz disk and thus being under floating plasma potential was constructed. Paraxial brightness of 313 А/m2rad2eV was obtained experimentally after beam passing through the exit aperture with diameter of 1 mm.