Timing performance characterization of FBK SiPM NUV-HD-MT technology

Abstract—The improvement of the timing performance is one of the main focus for several fields from high energy physics to biomedical applications such as Time of Flight Positron Emission Tomography (ToF-PET). In the last years, excellent results in terms of Single Photon Time Resolution (SPTR) and Coincidence Time Resolution (CTR) have been achieved thanks to the improvement of the scintillator crystal materials, the electronics readout and the detector development. In this study we will present SPTR and CTR measurements of the recently introduced FBK NUV-HD Metal in Trench (MT) SiPM technology. Thanks to the addition of the optically insulating material inside the trenches, FBK NUV-HD-MT devices show an extremely low CrossTalk (CT) of about ≃ 5% at 47.5V (≃ 15V excess bias). The Photon Detection Efficiency (PDE) reaches the ≃ 65% at the same excess bias at 420nm. By using a femto-second laser with a wavelength of 390nm, we have measured the SPTR for SPADs with different microcell sizes and different versions with a metal mask outside the active area (capacitive coupling). Moreover, a 1mm × 1mm and a 3mm × 3mm SiPM with 40μm cell size and M0 masking version have been tested. The CTR has been measured using a 4mm × 4mm SiPM to match the 3mm × 3mm × 5mm LYSO:Ce:Ca crystal. By using a high frequency readout elec- tronics, we achieved a CTR of about ≃ 80ps FWHM and an outstanding SPTR of about ≃ 19ps and ≃ 30ps FWHM for the SPAD and 1mm × 1mm SiPM with 40μm M0 masking respectively. This work opens the door to further investigations in order to study the worsening of the SPTR as the SPAD size increases but also to understand the role of the metal masking in the timing performance and to discuss about limitations and further improvements.