Effect of Silicon Photomultiplier Optical Crosstalk on
Detection Performance in Organic Scintillators

J. Fritchie - Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois
J. Balajthy - Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois
M. Sweany - Sandia National Laboratories
T. Weber - Sandia National Laboratory
A. Di Fulvio - Sandia National Laboratories
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This paper presents a method to reduce optical crosstalk (OCT) in a MicroFJ30035 silicon photomultiplier (SiPM) by ONSemi, which is a solid-state photon detector capable of detecting single photons. SiPMs are a promising alternative to vacuum photomultiplier tubes in radiation detection scenarios that require low-voltage power requirements, small form factor, and durability. However, the applicability of SiPMs in harsh environments is currently limited due to their temperature-dependent noise, which degrades their signal-to-noise ratio. One of the main sources of noise in SiPMs is OCT, which arises when a photon is produced during an avalanche, and the resulting photon can then trigger another avalanche in neighboring pixels, leading to false counts. Therefore, reducing OCT is crucial to enhance the performance of SiPMs in high-temperature environments. In this report, we explore a method to reduce OCT in 3mm x 3mm SiPMs by placing a series of Schott bandpass filters over the sensor of the SiPM. Filters with various spectral characteristics were tested on their abilities to suppress unwanted crosstalk signals while preserving the desired signal. We demonstrate the effectiveness of the filters by measuring the OCT in the SiPM before and after the filter installation and show a significant reduction in the OCT.