A time-resolution study with a plastic scintillator read out by a   Geiger-mode Avalanche Photodiode
  In this work we attempt to establish the best time resolution attainable with a scintillation counter consisting of a plastic scintillator read out by a Geiger-mode Avalanche Photodiode. The measured time resolution is inversely proportional to the square root of the energy deposited in the scintillator, and scales to 18ps (sigma) at 1MeV. This result competes with the best ones reported for photomultiplier tubes. 
A.Stoykov, R.Scheuermann, K.Sedlak
physics.ins-det