  The Hamamatsu UV-light enhanced 64-channel SiPM array of the newest
generation (S13361-3050AS-08) has been examined for the purpose of being used
for the Silicon Elementary Cell Add-on (SiECA) of the EUSO-SPB balloon
experiment. Characterization measurements have been performed with the newly
installed Single Photon Calibration Stand at KIT (SPOCK). The results of the
characterization measurements including the breakdown voltage, the gain, the
PDE, the dark-count rate and the crosstalk probability of all 64 SiPM channels
are presented. Additional measurements of the SiPM sensitivity to photons with
wavelengths lower than 400nm show an improved PDE for small wavelengths
compared to the SiPM array S12642-0808PA-50, which was also investigated for
comparison. The response dynamics have been investigated for low numbers of
incoming photons. Temperature dependent measurements of the gain, the PDE, the
dark-count rate and the crosstalk probability have been performed for one
channel of the SiPM array.
