Optical crosstalk in SiPMs

HAMPEL, M.R.; FUSTER, A.; VARELA, C.; PLATINO, M.; ALMELA, A.; LUCERO, A.; WUNDHEILER, B.; ETCHEGOYEN, A.

NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH A - ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPAMENT

ELSEVIER SCIENCE BV

Año: 2020 vol. 976

0168-9002

t was observed that the optical crosstalk probability (𝐶𝑇) of the silicon photomultipliers (SiPMs) of the electronics in all the AMIGA muon counter modules installed at the Pierre Auger Observatory was reduced by a factor of ∼2.68 after its deployment. This effect motivated the study of the optical crosstalk in SiPMs, in particular, the external interface optical crosstalk (𝐸𝐼𝐶𝑇 ). In this paper, two laboratory measurements were performed to evaluate the 𝐶 𝑇 , and a model to simulate the 𝐸 𝐼𝐶 𝑇 is proposed. We show that combining 𝐶 𝑇 measurements with simulations, the 𝐸𝐼𝐶𝑇 can be precisely estimated. We also obtained the internal optical crosstalk of the tested SiPM and it was (1.27 ± 0.05)%. This study shows that the thickness of the protective window of the SiPM and the optical system to which the SiPM is coupled affects optical crosstalk. We conclude that the 𝐸𝐼𝐶𝑇 is not negligible and for some cases it is the main contribution to the total optical crosstalk in SiPMs. Taking advantage of the 𝐶𝑇 variations depending on the optical system to which the SiPM is connected, we propose a method to validate the proper installation of the electronics in the muon counters modules of AMIGA.