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Low frequency ECR plasma sources have demonstrated their efficiency, reproducibility and long life time for the production of positive light ions. In 2003, the new 2.45 GHz ECR test stand based on a pure volume H- ion production, developed at CEA/Saclay, showed a dramatic increase of the H- extracted ion beam. In fact, a stainless steel grid now divides the plasma chamber in two different parts: the plasma generator zone and the negative ion production zone. By optimizing the grid position and its potential with respect to the plasma chamber, the negative ion current reached close to 1 mA. Ceramic plates, covering the plasma chamber walls help electron density and lead to an optimisation of the ion production. A 50 % improvement has been observed. A new 6 kW magnetron RF generator now replaces the 1.2 kW previous one and the current will be soon plotted versus the RF power. New Langmuir probe measurements are also expected on both sides of the grid. The last results will be reported and discussed.
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