[en] A source of gas ions is described which forms an ion beam of 200 mm in diameter with a current-density-distribution nonuniformity of ≤ ±10% over the cross-section and a current of up to 30 mA at an accelerating voltage of up to 50 kV. Nitrogen, argon, and air were used as working gases. Ion-emitting plasma was generated by a volume reflecting discharge that was initiated and supported by electrons injected from auxiliary reflecting cold-cathode discharge. Ion acceleration and formation of the beam were performed with a three-electrode multiaperture ion-optical system