Production and suppression of {sup 11}C in the solar neutrino experiment Borexino

Cosmogenic {sup 11}C is produced in-situ by atmospheric muons and forms the main background for the measurement of solar pep- and CNO-neutrinos. However, FLUKA simulations show that the majority of {sup 11}C is accompanied by a free neutron in the final state, thus allowing for an efficient tagging method, the so-called Three-Fold Coincidence technique. The technique and its first applications on Borexino data are presented.