1. Solar Process Technology, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
2. MGC-Plasma AG, CH-4132 Muttenz, Switzerland
3. Institute of Energy Technology, Department of Mechanical and Process Engineering, ETH - Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zurich, Switzerland and Solar Process Technology, Paul Scherrer Institute, CH-5232 Villigen, Switzerland