Two approaches for H- ion production with 2.45 GHz ion sources

For few years, the accelerator community requests progress to improve the development of negative hydrogen ion sources. For spallation sources like SNS or ESS, pulsed high intensity H- beams ranging few tens of milli amperes were required with duty cycle close to 10 %. New facilities like CERN ask also high performance negative ion beams. After CEA undertook an ECR based ion source program, a European network devoted to high performance negative ion source development was created. In this group, several laboratories developing 2.45 GHz ECR sources follow different approaches to increase the extracted current. At Saclay, with a solenoidal magnetic structure based on coils, close to 4 mA of H- ion beam is now extracted in pulsed mode (2 ms/100ms). At Ecole Polytechnique, on the source Camembert III, photodetachment measurements showed comparable H- ion creation whether the primary electrons are provided by filaments or small ECR modules inserted in the plasma chamber. Both experiments as well as future plans will be reported. (author)