Silicon photomultiplier multichannel arrays for the LHCb scintillating fibre tracker

A scintillating fibre tracker read out by silicon photomultipliers (SiPMs) will be used in the upgrade particle tracking system of the LHCb detector at CERN. The multichannel SiPM array from Hamamatsu HPK is optimized for high photo-detection efficiency (PDE)and low correlated noise. The selected SiPM shows a peak PDE of up to 52% at 475 nm, low pixel-to-pixel cross-talk (3%) and almost zero after-pulse. Measurements on detectors irradiated with neutrons up to 12 × 10¹¹ n_eq/cm² demonstrate that the detector characteristics remain unchanged after irradiation apart from a large increase of the dark count rate (DCR).