A miniature version of the ICAL experiment at the India-based Neutrino Observatory, the mini-ICAL
is in operation at the IICHEP, Madurai. The commissioning work of a Cosmic Muon Veto detector (CMVD)
on top of the mini-ICAL is continued using extruded plastic scintillators with embedded
WLS fibers and the SiPM as a photo-transducer. The CMVD is being built to study the
feasibility of a cosmic muon veto for a shallow-depth neutrino experiment. The SiPM is calibrated
using an ultrafast LED driver and
the same calibration techniques will be used during the data taking period with a simplified LED in the
same readout PCB. An experimental setup was
designed to characterise the SiPMs in a temperature controlled environment. The readout electronics
involves trans-impedance amplifiers and a voltage followers of combined gain 1.24 mV/$\mu$A and a
digital storage oscilloscope for the data collection with a minimal distortion of SiPM signal.
Various characteristics of the Hamamatsu SiPM (S13360-2050VE), e.g. signal shape, optically correlated
and uncorrelated noise, recovery time etc were studied as a function of $V_{ov}$, number of photoelectrons,
the ambient temperature and the humidity. This paper will cover the details of those results.

