A velocity map imaging (VMI) spectrometer was constructed for observation of the slow ions produced by photofragmentation of C-60 with synchrotron radiation. The spectrometer was tested by observing the ion images of rare gases in the Maxwell-Boltzmann distribution at room temperature, and the effect of a large ionization volume inevitable in our experiment has been quantitatively characterized. Numerical simulations taking into account such instrumental parameters indicate that one can distinguish the two independent formation processes of C-56(+) from the primary precursor C-60(+): i.e., one-step ejection of C-4 and sequential ejections of two C-2 fragments. (C) 2008 Elsevier B. V. All rights reserved.