Studying the Operation of Silicon Photomultiplier Matrices at Cryogenic Temperatures

— The performance of MPPC 13360-6050PE SiPM matrices with parallel and series connections of elements under conditions of an experiment with a two-phase detector has been investigated, and theoretical calculations of the signal characteristics have been performed for these matrices. It is shown that the signal duration does not change with a high accuracy when SiPMs are connected in series but increases with the number of SiPMs in the matrix when SiPMs are connected in parallel. Within the measurement accuracy, the integral amplitude of the signal does not depend on the number of elements in a matrix in case of the parallel connection. For the series connection, the expected decrease in the amplitude is observed, and this decrease is inversely proportional to the number of elements in the matrix. Based on the results of this study, an SiPM matrix consisting of four parallel-connected elements has been selected for further use in a two-phase cryogenic dark-matter detector since reliable detection of single-photoelectron pulses by this matrix has been demonstrated at an acceptable signal duration.