  We present herein gain stabilization studies of SiPMs using a climate chamber
at CERN. We present results for four detectors not tested before, three from
Hamamatsu and one from KETEK. Two of the Hamamatsu SiPMs are novel sensors with
trenches that reduce cross talk. We use an improved readout system with a
digital oscilloscope controlled with a dedicated LabView program. We improved
and automized the analysis to deal with large datasets. We have measured the
gain-versus-bias-voltage dependence at fixed temperature and
gain-versus-temperature dependence at fixed bias voltage to determine the bias
voltage dependence on temperature $V(T)$ for stable gain. We show that the gain
remains stable to better than $\pm 0.5\%$ in the $20^\circ \rm C - 30^\circ C$
temperature range if the bias voltage is properly adjusted with temperature.
