Alberto Gola (FBK)
We characterized the RGB SiPMs with Ultra-High-Density cells (RGB-UHD) manufactured at Fondazione Bruno Kessler (FBK), Trento. The devices feature circular cells, with a pitch of 7.5 um, 10 um and 12.5 um, corresponding to a cell density of 20500, 11500 and 7400 cells/mm2, respectively. Depending on different layout splits that we tested, the fill factor (FF) of the cells varies between 33% and 57%, for the 7.5um cell, and between 47% and 68%, for the 10 um cell. These cells have a very small capacitance and gain, thus featuring very fast recovery time, lower correlated noise and less sensitivity to radiation damage, when compared to larger cells built with a similar technology. Such characteristics are of great interest in applications that require high dynamic range and/or good resistance to radiation damage, such as the CMS ECAL upgrade. We tested samples of the UHD-SiPM technology, featuring a circular active area with 1.5 mm diameter. The experimental characterization showed that all the cell sizes and layout splits were working and capable of single-photon resolution. The microcell recharge time constant was 3.5 ns and 4.5 ns, for the 7.5 um and 10 um cells, respectively. At an overvoltage of 6 V, we measured an Excess Noise Factor below 1.1 for all cells and a DCR in the order of 200 KHz/mm2. The PDE at 515 nm was 22%, 26% and 29%, for the 7.5 um, 10 um and 12.5 um cells, respectively, which are very high values, considering the small cell sizes.
Alberto Gola (FBK)
Alessandro Ferri (FBK) Arjan Heering (University of Notre Dame (US)) Claudio Piemonte (FBK) Fabio Acerbi (FBK) Gaetano Zappalà (FBK) Giovanni Paternoster (FBK) Nicola Zorzi (FBK) Randy Ruchti (University of Notre Dame (US)) Veronica Regazzoni (FBK) Yuri Musienko (University of Notre Dame (US) and INR (Moscow))