Status of the Negative Hydrogen Ion Test Stand at CEA Saclay

At CEA‐Saclay, in 2003, the new 2.45 GHz ECR source, based on pure volume H− ion production, showed a dramatic increase of the H− extracted ion beam. In fact, since the rectangular plasma chamber is separated in two different parts by a stainless steel grid, the extracted H− current rose from few μA to 1.5 mA. Of course the grid position and its potential with respect to the plasma chamber were optimised. Ceramic plates allow increasing the electron density and lead to an improvement of the negative ion production. Plasma characterization by using Langmuir probes and positive charge analysis are also presented. The last results are reported and discussed. This work is part of the High Performance Negative Ion Sources (HPNIS) program and supported by the European Union under contract HPRI‐CT‐2001‐50021.