Wimmer, C., Berner, J., Heiler, A., Merk, F., Zielke, D., Fantz, U., et al. (2023). From surface production to extraction in negative hydrogen ion sources: diagnosing H- and its precursors. Talk presented at 49th EPS Conference on Plasma Physics. Bordeaux. 2023-07-03 - 2023-07-07.