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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 \times\,4 mm SiPMs produced at FBK coupled to 3.8 mm \times\,3.8 mm \times\,5 mm Teflon-wrapped LYSO crystals. [ABSTRACT FROM AUTHOR]

Abstract: The use of Silicon Photo-Multipliers (SiPMs) as photon detectors in Positron Emission Tomography (PET) modules offers significant advantages over conventional light sensors, including application in a magnetic field, better resolution and easier operation. Different types of SiPMs have been tested: Photonique, 2.1×2.1mm2, Hamamatsu 3×3mm2 and STMicroelectronics 3.5×3.5mm2. Dark noise, surface sensitivity, photon detection efficiency and linearity at low light intensities have been measured. A LYSO crystal was coupled to a SiPM to test the performance as a photon detector for PET. We will present the results of the measurements for different samples and types. [ABSTRACT FROM AUTHOR]

Abstract: A novel photon detector, the Silicon Photomultiplier (SiPM), has been tested in view of a photosensitive device for Positron Emission Tomography (PET), which is one of the most important non-invasive methods for in-depth and in vivo imaging of tissue. Such a device offers advantages over existing ones, including application in a magnetic field, better resolution and easier operation. Two PET modules have been constructed by coupling an array of Hamamatsu 3mm×3mm Multi-pixel photon Counters (MPPCs) and Photonique 2.2mm×2.2mm Solid-state Photomultipliers (SSPMs) to LYSO scintillation crystals. The results of studies of the two module prototypes are presented. [ABSTRACT FROM AUTHOR]