Microlens-enhanced SiPMs

TL;DR

This paper introduces a microlens array technique to significantly improve the photo-detection efficiency and reduce cross-talk in silicon photomultipliers, enhancing their performance for high-radiation environments.

Contribution

The study presents a novel microlens-based design for SiPMs that increases PDE and reduces cross-talk, validated through simulation and experimental measurements.

Findings

PDE improved up to 24%

External cross-talk reduced by 40%

Enhanced single photon time resolution

Abstract

A novel concept to enhance the photo-detection 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 checkerboard arrangement and aims to deflect the light from the dead region of the pixelised structure towards the active region in the center of the pixel. The PDE is improved up to 24%, external cross-talk is reduced by 40% compared to a flat epoxy layer, and single photon time resolution is improved. This detector development is conducted in the context of the next generation LHCb scintillating fibre 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.