Speaker
Description
Silicon photomultipliers (SiPMs) are increasingly adopted as the photosensors of choice in next-generation dark matter experiments due to their high photodetection efficiency and low operating voltage. In large detector arrays, however, SiPM performance can be significantly degraded by correlated noise processes, particularly external cross-talk, in which photons emitted from the triggering of one sensor induce spurious signals in neighboring devices. Understanding and mitigating this effect is critical for achieving the sensitivity required for rare-event dark matter searches such as DarkSide-20k.
I present a comprehensive experimental characterization of DarkSide-20k SiPMs performed under experiment-like cryogenic and vacuum conditions. Measurements were carried out using the Vacuum Emission Reflection and Absorption (VERA) setup at TRIUMF to determine key parameters involved in quantifying correlated noise, including dark count rate (DCR), breakdown voltage, and angular photodetection efficiency.
A particular focus of this work is the measurement of the angular dependence of SiPM photodetection efficiency, which directly influences the probability and spatial distribution of external cross-talk in densely packed SiPM arrays. The measured angular response provides new data that will be used in Monte Carlo simulations of correlated noise in DarkSide-20k. These results enable more realistic modeling of external cross-talk and allow quantitative assessment of its impact on detector performance and overall experimental sensitivity as a function of detector geometry and operating parameters.
The characterization data presented here represent an important step toward improving the accuracy of SiPM noise modeling in large noble-liquid detectors. Incorporating these measurements into simulation frameworks will aid in the optimization of detector design and experimental geometry, contributing to enhanced sensitivity in current and future SiPM-based dark matter searches.
| Keyword-1 | Silicon photomultipliers |
|---|---|
| Keyword-2 | External cross-talk |
| Keyword-3 | Detector instrumentation |