The DLED Algorithm for Timing Measurements on Large Area SiPMs Coupled to Scintillators

One of the main factors limiting the precision of timing measurements with silicon photomultipliers coupled to scintillators is the dark noise, especially in the case of large devices. In order to cope with it, a suitable signal processing should be employed. The method we propose is called differential leading edge discriminator (DLED) and allows an effective compensation of the baseline fluctuations due to the dark counts of the detector. In this paper we show a comparison between the measurements obtained using the traditional Leading Edge Discriminator technique and the DLED. The improvement we observe is remarkable. Combining this baseline correction algorithm with low temperatures, we were able to reach a coincidence resolving time of 180 ps FWHM, using 4 mm x 4 mm SiPMs produced at FBK coupled to 3.8 mm x 3.8 mm x 5 mm Teflon-wrapped LYSO crystals.