Formations of negative ions in Sf6/N2 mixtures and their transport at atmospheric pressure Yui Okuyama, Martin Sabo, Haruo Itoh and Štefan Matejčík Eur. Phys. J. Appl. Phys., 61 2 (2013) 24320 Published online: 15 February 2013 DOI: 10.1051/epjap/2012120448