https://doi.org/10.1140/epjc/s10052-025-14381-w
Regular Article - Experimental Physics
Characterization of external cross-talk from silicon photomultipliers in a liquid xenon detector
1
Physics Department, McGill University, H3A 2T8, Montreal, QC, Canada
2
TRIUMF, V6T 2A3, Vancouver, BC, Canada
3
Department of Physics, Carleton University, K1S 5B6, Ottawa, ON, Canada
4
Université de Sherbrooke, J1K 2R1, Sherbrooke, QC, Canada
5
Istituto Nazionale di Fisica Nucleare, 56127, Pisa, PI, Italy
6
Department of Physics, Queen’s University, K7L 3N6, Kingston, ON, Canada
7
Department of Physics and Astronomy, University of British Columbia, V6T 1Z1, Vancouver, BC, Canada
8
Department of Physics, Simon Fraser University, V5A 1S6, Burnaby, BC, Canada
9
Stanford University, 94305, Stanford, CA, USA
10
Research Center for Nuclear Physics, Osaka University, Osaka, Japan
11
University of Toronto, M5S 3E4, Toronto, ON, Canada
a
david.gallacher@mail.mcgill.ca
Received:
25
February
2025
Accepted:
28
May
2025
Published online:
24
June
2025
The Light-only Liquid Xenon experiment (LoLX) employs a small-scale detector equipped with 96 Hamamatsu VUV4 silicon photomultipliers (SiPMs) submerged in 5 kg of liquid xenon (LXe) to perform characterization measurements of light production, transport and detection in xenon. In this work, we perform a novel measurement of the “external cross-talk” (ExCT) of SiPMs, where photons produced in the avalanche escape the device and produce correlated signals on other SiPMs. SiPMs are the photodetector technology of choice for next generation rare-event search experiments; understanding the sources and effects of correlated noise in SiPMs is critical for producing accurate estimates of detector performance and sensitivity projections. We measure the probability to observe ExCT through timing correlation of detected photons in low-light conditions within LoLX. Measurements of SiPM ExCT are detector dependent; thus the ExCT process is simulated and modelled using the Geant4 framework. Utilizing simulations, we determine the average transport and detection efficiency for ExCT photons within LoLX, a necessary input to extract the true ExCT probability and detector independent photon emission intensity. For an applied overvoltage of 4 V and 5 V, we measure a mean number of photons emitted into LXe per avalanche of 
and 
respectively. Using an optical model to describe photon transmission through the SiPM surface, this corresponds to an estimated photon yield inside the bulk silicon of 
and 
photons per avalanche. The relative increase in intensity of SiPM ExCT emission between 4 and 5 V is consistent with expectation for the linear increase of gain with respect to overvoltage.
This work was supported by the respective institutions and includes updated correspondence details.
© The Author(s) 2025
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Funded by SCOAP3.
