Understanding of the noise of the SiPM

The prototype detector of the ICAL experiment at the India-based Neutrino Observatory, the mini-ICAL is in operation at the IICHEP, Madurai. A Cosmic Muon Veto detector (CMVD) around the mini-ICAL is being commissioned using extruded plastic scintillators with embedded WLS fibers. The SiPM is used as a photo-transducer and that will be calibrated using an ultrafast LED driver. Other than the basic efficiency and gain study for the CMVD as a function of overvoltage ($V_{ov}$), an experimental setup was designed to characterise the SiPMs in a temperature controlled environment. The readout electronics involves trans-impedance amplifiers followed by an opamp buffer stage to drive the outputs of combined gain 1.24 mV/$\mu$A and a digital storage oscilloscope for the data collection without much distortion of SiPM signal. The characteristics of the correlated and uncorrelated noise of Hamamatsu SiPM (S13360-2050VE) were studied as a function of $V_{ov}$, the ambient temperature and those are described in this paper.