NIO1 a Versatile Negative Ion Source

The development of neutral beam injectors (NBI) for tokamaks like the ITER project requires high performance and huge negative ion sources (40 A of D- beam required); it was recently accepted that inductive plasma coupled (ICP) radiofrequency sources are the preferred option. It is therefore useful to have a moderate size source of modu- lar design to test and verify both construction technologies and components and simulation codes; here the NIO1 de- sign (60 kV, 9 beamlets of 15 mA H- each) and construction status are described. Source is assembled from disk shaped modules, for rapid replacement; the beamlets are arranged in 3 times 3 square matrix. Solution for strong electrodes water cooling, magnetic filter control and cesium regula- tion are described.