Advanced NBI beam characterization capabilities at the recently improved test facility BATMAN Upgrade

• Published in: Fusion engineering and design Vol. 146; pp. 212 - 215
• Main Authors: Fantz, U., Bonomo, F., Fröschle, M., Heinemann, B., Hurlbatt, A., Kraus, W., Schiesko, L., Nocentini, R., Riedl, R., Wimmer, C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2019; Elsevier Science Ltd
• Subjects: Divergence; Hydrogen ions; Ion sources; ITER; Negative ion source; Negative ions; Neutral beam injection; Radio frequency source; Spatial resolution; Thermocouples; Tungsten; Wire; Neutral beam injection; Negative ion source; ITER; Radio frequency source
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2018.12.020

The test facility BATMAN was dedicated since its start in 1996 to the development of radio frequency driven negative hydrogen ion sources for ITER NBI with focus on formation and extraction of negative ions, technological developments and improved concepts. During 2017, the test facility was upgraded in order to replace the former extraction system with a new ITER-like extraction system comparable in size to one ITER beamlet group and having the option to flow a current through the grid creating a magnetic filter field as foreseen for the ITER sources. In addition, the beam diagnostics has been extended: beam emission spectroscopy is located at two positions from the grounded grid (26 cm and 129 cm) with spatial resolution in vertical direction. A newly developed tungsten wire calorimeter is placed just 19 cm downstream the grounded grid to provide quantitative measurements of individual beamlets, whereas the tungsten wire calorimeter at 180 cm distance is still in use for qualitative beam profile diagnostics. Together with a beam dump calorimeter with a crosswise arrangement of thermocouples, beam divergence and uniformity can be studied. This is accompanied by modeling the beamlet transport from the extraction system up to the calorimeter. Results from the first experimental campaign are reported, being very promising for detailed understanding of features measured on large beams.