Silicon photomultiplier (SiPM), a new type of photosensor, is considered a substitute for traditional photomultiplier tube (PMT) in the next generation of dark matter and neutrino detectors, especially in noble gas detectors like liquid argon. However, the design of compact SiPM arrays and their cryogenic electronics that can work in liquid argon is barely developed. Thus, two candidate SiPM arrays from Hamamatsu and Onsemi were selected to verify the feasibility and effectiveness of the design. In this work, we successfully developed a cryogenic electronics read-out system that connects and works with 1-inch 4×4 SiPM arrays at 87 K. The power dissipation of amplifiers is less than 10 µW/mm 2 . Furthermore, multiply significant characteristics of both types of SiPM arrays were measured at liquid argon temperature, such as dark count rate (DCR), breakdown voltage (V bd ), single photoelectron (SPE) performance, signal to noise ratio (SNR) and correlated signal probability.

83m Kr and 22 Na have been used in calibrating a liquid argon (LAr) detector. 83m Kr atoms are produced through the decay of 83 Rb and introduced into the LAr detector through the circulating purification system. The light yield reaches 7.26±0.02 photonelectrons/keV for 41.5keV from 83m Kr and 7.66±0.01 photonelectrons/keV for the 511keV from 22 Na, as a comparison. The light yield varies with the drift electric field from 50 to 200V/cm have been also reported. After stopping fill, the decay rate of 83m Kr with a fitted half-life of 1.83±0.11 h, which is consistent with the reported value of 1.83±0.02 h.

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