Cryogenic characterization of Hamamatsu HWB MPPCs for the DUNE photon detection system

Abstract

The Deep Underground Neutrino Experiment (DUNE) is a next generation experiment aimed to study neutrino oscillation. Its long-baseline configuration will exploit a Near Detector (ND) and a Far Detector (FD) located at a distance of ∼1300 km. The FD will consist of four Liquid Argon Time Projection Chamber (LAr TPC) modules. A Photon Detection System (PDS) will be used to detect the scintillation light produced inside the detector after neutrino interactions. The PDS will be based on light collectors coupled to Silicon Photomultipliers (SiPMs). Different photosensor technologies have been proposed and produced in order to identify the best samples to fullfill the experiment requirements. In this paper, we present the procedure and results of a validation campaign for the Hole Wire Bonding (HWB) MPPCs samples produced by Hamamatsu Photonics K.K. (HPK) for the DUNE experiment, referring to them as `SiPMs'. The protocol for a characterization at cryogenic temperature (77 K) is reported. We present the down-selection criteria and the results obtained during the selection campaign undertaken, along with a study of the main sources of noise of the SiPMs including the investigation of a newly observed phenomenon in this field.

Enhancement of the DUNE FD1 X-ARAPUCA Photon Detection Efficiency and upgrade of the FD2 Photon Collector

“…For the three XA configurations, 𝜏 t was found to range from 910 ns to 1510 ns corresponding to a maximal LAr purity correction (for the 910 ns value) of ∼ 10%. As for the SiPMs X-talk, it has been measured at 77 K (11.0 ± 1.0)% and (16.05 ± 0.32)% for the HPK [19] and FBK SiPMs respectively. The PDE assessed by the MiB method (𝜖 MiB ) is the average of the PDE values measured along the XA device length (usually 6-12 points) and accounts for the devices non uniformity as the SiPM-to-WLS gaps originated from the components tolerances, (slightly) different SiPMs gain etc.…”

“…The number of detected photons is then corrected for the actual LAr yield, measured at each filling i.e. for each XA configuration by the LAr triplet half-life (𝜏 t ) [18], and for the SiPMs cross-talk [19]. At each filling, the 𝜏 t is measured and monitored along the one-day long PDE measurement campaign.…”