Measuring Photon Time Spread Distribution of Scintillators on the Picosecond Time Scale

In the search for scintillators that have a faster response than existing ones, better knowledge on the processes that take place during the first 100 ps of the scintillation process is required. For that one needs detailed information on the intrinsic rise time of a scintillation pulse. However, the observed rise time, also of direct importance to the timing resolution, is strongly affected by the time spread of photons leaving the scintillator. In this work we pioneered the use of a 120 fs Ti-sapphire laser in combination with a streak camera system to measure those photon time spreads with time resolution up to 5 ps. With this setup the photon time spread distributions of scintillator crystals with different size and/or surface treatment were measured. The potential to study the effect of Teflon packaging on this distribution was also investigated.