[en] The first experimental results on the source of D^- negative ions developed at SIG confirm a certain number of essential points: (1) the use of a positive ion source obtained by a resonance electronic cyclotron permits the production of D⁺ ion beams with a very small gas output, therefore it has a very good gas efficiency; (2) the supersonic cesium target obtained after the release of a high temperature cesium vapor functions perfectly with the desired characteristics; (3) the conversion efficiency measured in D^- ions is close to those which were deduced from experimental cross sections; and (4) the mean density of D^- ion currents is on the order of 10 mA/cm² at 1 keV. They could be 15 at 25 mA/cm² at 300 eV. This presupposes that we modify the extraction optic for the D⁺ ions to extract 60 at 70 mA/cm² of D⁺ at 300 eV with a maximum electric field of 30 DV/cm and a greater perveance of the optic