  An experimental method to characterize the crosstalk and afterpulsing in
silicon photomultipliers has been developed and applied to two detectors
fabricated by Hamamatsu. An analytical model of optical crosstalk that we
presented in a previous publication has been compared with new measurements,
confirming our results. Progresses on a statistical model to describe
afterpulsing and delayed crosstalk are also shown and compared with preliminary
experimental data.
