The matrices formed of silicon photomultipliers (SiPMs) are very promising photosensors for the scintillation detectors. We present preliminary results of characterization study of prototype of such detector. The matrix of 8x8 SiPMs from SensL company (ABL-ARRAYB64P-HDR) was chosen as photosensor. Each of the 64 SiPM has size of 6x6 mm^2 and consists of 18 980 micropixels. Measurements of the SiPM operation parameters were carried out for all individual SiPMs of the matrix. The relative change in the quantum efficiency of the SiPMs depending on the angle of incidence of the photon have been measured. Measurements of the proper gamma background of the matrix have been performed. The background count rate of the matrix due to proper radioactivity has been estimated.

INR RAS