Microlens-Enhanced SiPMs

A novel concept to enhance the photodetection efficiency (PDE) of silicon photomultipliers (SiPMs) has been applied, and remarkable positive results can be reported. This concept uses arrays of microlenses to cover every second SiPM pixel in a chequerboard arrangement and aims to deflect the light from the dead region of the pixelized structure toward the active region in the center of the pixel. The PDE is improved up to 24%, external crosstalk is reduced by 40% compared to a flat epoxy layer, and single photon time resolution (SPTR) is improved. This detector development is conducted in the context of the next-generation Large Hadron Collider beauty (LHCb) scintillating fiber tracker (SciFi Tracker) located in a high radiation environment with a total of 700’000 detector channels. The simulation and measurement results are in good agreement and will be discussed in this work.