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We are building the SOPHI experiment in Saclay, which is a device based on a small 5 MeV electron linac [1] to produce positrons via pair production on a tungsten target. This device should provide 108 slow e+/s, i.e. a factor 300 greater than the strongest activity Na22 based setup. The SOPHI system has been finalized at the end of 2006 and the main components have been studied and built during 2007 [2]. The experiment is currently being assembled and first results are expected for autumn 2008. The electron linac, positron beam production and transport system will be presented, and expected positron production rate reported.

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.

H− ions have now been observed in currents extracted from the CEA/Saclay ECR proton source. A pulsed, 90 degree dipole magnet has been installed 14.8 cm downstream from an ion beam extraction system designed to operate up to 10 kV. The plasma chamber can be biased by a negative or positive HV power supply and the diagnostics are grounded. The magnetic field is reduced to 200 G at the emission aperture. The measured positive hydrogen ion fractions show a large amount of H2+. A 32 wire profiler has also been installed at the dipole magnet location to analyze the total extracted beam and compare it with calculations. Profile measurements at negative extraction potential indicate an important deflection of the beam when the magnetic filter is installed. To measure a consistent electron to H− ratio, the magnetic filter has been tuned in order to avoid steering the beam off axis. Preliminary results will be reported as well as analysis of the profile. This work is supported by the European Commission under cont...

ECR Ion Sources are well known for their efficient production of Highly Charged Ions [1], and also for the production of intense proton beams [2]. Recently European laboratories have decided to join their efforts to develop and improve various plasma techniques for the production of intense beams of H−, for a future application to the European Spallation Source, and possibly for other high power accelerators. Because of its great experience and skill in ECR plasmas and ion sources, CEA has decided to develop ECR ion sources for negative ion production. At first glance, this seems to be a real challenge, as negative ion production requires a very low electron temperature, incompatible with ECR heating. We will show that this contradiction can be solved. In this article we briefly summarize the present status of Negative Ion Sources (NIS). Then we describe ECR Ion Sources and how they can be of great interest for H− production. Although this domain is still rather unexplored, some work has already been performed in the field of negative ion production with ECR plasmas. That work will be shortly summarized. Eventually promising preliminary results, obtained at CEA Saclay at 2.45 GHz, will be shown.