Investigation of plasma parameters at BATMAN for variation of the Cs evaporation asymmetry and comparing two driver geometries

Performance of the BATMAN RF source with a large racetrack shaped driver

“…In the OES spectra a higher line ratio H /H 2,Fulcher has been measured in the racetrack driver at the same power, which is equivalent to a slightly higher dissociation degree [5].Considering the larger driver volume this corresponds to a much larger flow of hydrogen atoms out of the driver. Because the atoms contribute predominantly to the surface conversion, a more efficient H -production can be expected.…”

“…Another difference is that the walls of the expansion volume are exposed to higher plasma density than in the previous source, so much less Cs can be trapped on the walls. Both issues lead to a different Cs dynamics in the sources [5].The distribution of the plasma light has been observed by a camera from the top side of a 19 cm long expansion volume which is equipped with more diagnostic ports. Figure 3 shows impressively the effect of magnetic filter field on the expanding plasma.…”

“…The diagnostic system includes electrical current measurements, two Langmuir probes, the tips located 7 mm from the plasma grid, optical emission spectroscopy (OES) on the backplates of the drivers, the line of sight perpendicular to the plasma grid on and cavity ring-down spectroscopy (CRDS) 22 mm from the plasma grid [5].…”

Beam characterization at BATMAN for variation of the Cs evaporation asymmetry and comparing two driver geometries

“…In this work a second oven was installed at the bottom part of the source back plate. By evaporating from either the top or the bottom oven the Cs asymmetry in front of the PG changes [4]. The possible influence of this asymmetry on the beam profile was investigated with the two beam diagnostics.…”

“…The effect of these factors is investigated for two modifications applied to the prototype: varying the Cs evaporation asymmetry inside the source and changing the driver geometry. A parallel study focused on the plasma parameters for these modifications was conducted and reported in [4].…”