Negative ion test facility ELISE—Status and first results

Abstract

The new test facility ELISE (Extraction from a Large Ion Source Experiment) has been designed and installed since November 2009 at IPP Garching to support the development of the radio frequency driven negative ion source for the Neutral Beam System on ITER. The test facility is now completely assembled; all auxiliary systems have been commissioned and are operational. First plasma and beam operation is starting in October 2012.The source is designed to deliver an ion beam of 20A of D− ions, operating at 0.3Pa source pressure at an electron to ion current ratio below 1. Beam extraction is limited to 60kV for 10s every 3minutes, while plasma operation of the source can be performed continuously for 1hour. The ion source and extraction system have the same width as the ITER source, but only half the height, i.e. 1×1 m2 source area with an extraction area of 0.1 m2. The aperture pattern of the extraction system and the multi driver source concept stay as close as possible to the ITER design. Easy access to the source for diagnostic tools or modifications allows to analyze and optimize the source performance. Among other possibilities many different magnetic filter field configurations inside the source can be realized to enhance the negative ion extraction and to reduce the co-extraction of electrons. Beam power and profiles are measured by calorimetry and thermography on an inertially cooled target as well as by beam emission spectroscopy. Cs evaporation into the source is done via two dispenser ovens.