A large aperture Hall current accelerator has been developed for ion cleaning of substrates before vacuum arc deposition of protective and decorative layers. The accelerator has a large aperture of 1400 mm and a power up to 10 kW. High ion currents permit one to use the source also for ion implantation. Various gases can be used for both purposes: argon, nitrogen, oxygen, etc. The current-voltage characteristics for nitrogen at various pressures are presented. The ion implantation of nitrogen was performed into austenitic stainless steel at a discharge voltage of 900 V and a discharge current of 3 A. The depth profiles were measured with the aid of secondary-ion mass spectroscopy. The load dependence of the microhardness after ion nitriding was measured.