  Gain and photon detection efficiency (PDE) of silicon photomultipliers
(SiPMs) are important characteristics to understand SiPM-based detector systems
in low light level applications. In this work, experimental setups are
developed to quantify SiPM gain and PDE at different temperatures and bias
voltages with a light source of fixed wavelength 405 nm, where a novel
light-tight connected device of two integrating spheres is implemented to
produce weak light onto SiPM. We present methods and results of the breakdown
voltage, gain and PDE measurements for a Hamamatsu S13360-2050VE MPPC. At 25
Celsius, consistent results are obtained with the datasheet from the
manufacturer. The temperature and bias voltage dependence of SiPM performances
can guide its usage, such as in gain compensation at readout circuits, optical
modeling of SiPMs and optimization of operating conditions of SiPM-based
detectors.
