Light pulses to photomultiplier tubes from extended scintillators

Light pulses seen by photomultiplier tubes (PMTs) after propagation within long scintillator slats or rods, or large disc-shaped scintillators are investigated and compared with those from point-like scintillators. Results of experimental tests for the disc-shaped configuration, performed with the single photon counting technique, are presented and compared with numerical calculations. These calculations were performed describing the light pulse shape by means of a new, quite general analytical method based on the geometrical optics concepts of virtual light paths and images. The associated electric pulses produced by the PMTs coupled to the scintillators are then discussed with particular emphasis on their dependence on the distance between light source and photocathode.