Characterization of undoped CsI at cryogenic temperatures

Doped CsI (Cesium iodide) and NaI(Sodium iodide) are widely used as detectors to detector the neutrinos event. 185Kg NaI[Tl] has been used as detector in COHERENT. But pure CSI can only perform well at low temperature due to its scintillator mechanism. The light yield at low temperature is even better than that of doped CsI and NaI. So, we want to study its characterization at low temperature. The light yield has been measured over the temperature range from 1.7K to 300K. But the nuclear recoil quenching factor haven’t been measured at low temperature. In this talk, we will describe the experiment of our light yield and quenching factor measurement of the pure CsI at 77K.