The source of “background” fission events in experiments on superheavy elements S. Heinz, S. Hofmann, V. Comas, D. Ackermann, J. Heredia, F. P. Heßberger, J. Khuyagbaatar, B. Kindler, B. Lommel and R. Mann Eur. Phys. J. A, 48 3 (2012) 32 Published online: 19 March 2012 DOI: 10.1140/epja/i2012-12032-7