Cryogenic characterization of FBK NUV-HD-Cryo 3T SiPM sensors for the DUNE photon detection system

TL;DR

The paper evaluates FBK NUV-HD-Cryo 3T SiPMs for the DUNE FD-HD PDS to enable cryogenic detection of argon scintillation photons. It compares 1T and 3T layouts, showing that the 54 μm pitch with triple DTIs (3T) provides higher gain while maintaining low cross-talk, leading to its selection for DUNE. A large, cross-lab cryogenic characterization program measures IV, DCR, gain, and PDE at 87 K using a unified protocol and the VER A PDE setup, confirming performance targets and identifying burst noise as a main caveat. PDE measurements across 350–600 nm show favorable response with no significant degradation relative to room temperature within the tested range, and the sensors meet the required PDE. The work provides a validated, reproducible assessment framework for deploying FBK 3T sensors in the DUNE PDS and informs design choices for the photon detection system.

Abstract

The Deep Underground Neutrino Experiment (DUNE) is a long-baseline neutrino experiment based in the USA and composed of a Near Detector (ND) complex at Fermi National Laboratory (FNAL), and a Far Detector (FD) complex located at the Sanford Underground Research Facility (SURF) $\sim$1300\,km distant. DUNE will study neutrino oscillations looking for unresolved issues of the Standard Model of particle physics (SM) such as CP violation in the leptonic sector, neutrino mass ordering and others, starting from the early 2030s. The FD, with a mass of $\sim$17\,kt, that will exploit both ionization and scintillation signals to detect neutrino interactions with Argon. Scintillating photons in LAr will be detected by the photon detection system (PDS) based on light collectors coupled to Silicon Photomultipliers (SiPMs). During a test campaign, different laboratories of the collaboration performed an investigation of the best SiPM candidates that fulfill the DUNE FD requirements. We identified two models of SiPM, produced by Hamamatsu Photonics K.K. (HPK) and Fondazione Bruno Kessler (FBK), respectively. In this paper, we focus on the FBK selected model showing its main features. We will describe the characterization protocol, the results at both room and cryogenic temperatures and the photon detection efficiency measurements.

Figures (14)

• Figure 1: a) Cross-section of the 30 µ m cell pitch device with a standard single DTI (1T – 30 µ m), b) Cross-section of the 54 µ m cell pitch device with three DTIs (3T – 54 µ m). High-field region in pink, quenching resistor in red, metal contact in black, passivation layer in blue, Active Reflective Coating in light blue and Deep Trench Isolation in gray.
• Figure 2: Comparison of the Gain as a function of the overvoltage between the two different splits (1T – 30 µ m; 3T – 54 µ m). Error bars lower than 1% not visible in the graph.
• Figure 3: Comparison of the direct CT probability as a function of the overvoltage between the two different splits (1T – 30 µ m; 3T – 54 µ m).
• Figure 4: Comparison of the PDE at room temperature and 435 nm as a function of the overvoltage between the two different splits (1T – 30 µ m; 3T – 54 µ m).
• Figure 5: Setup used for the characterization of the sensors. a) Sketch of the apparatus used for IV measurements. b) Sketch of the apparatus used for DCR study, c) Temperature of the PT100 sensor placed near the SiPM as a function of time during the diving in LN2 phase.