A C-60 monomer as an inherently monodisperse standard particle was produced by a C-60 vapor source equipped with an Am-241 neutralizer, and its mobility spectrum was measured by using a low-pressure differential mobility analyzer (LPDMA). The transfer function was derived from the mobility spectrum and was measured as dependences on aerodynamic and electrodynamic conditions. The experimental transfer function thus obtained was compared with the theoretical transfer function. (C) 2003 Elsevier Ltd. All rights reserved.