[1] Univ Sydney, Sch Aerosp Mech & Mechatron Engn, Sydney, NSW 2006, Australia
[2] Univ Sydney, Australian Ctr Microscopy & Microanal, Sydney, NSW 2006, Australia
[3] ETH, Zurich, Switzerland
[4] IMEC VZW, B-3001 Heverlee, Belgium
[5] Katholieke Univ Leuven, Inst Kern & Stralingsfys, B-3001 Leuven, Belgium