XMASS-I, the first phase of the XMASS implementation, is dedicated to direct dark matter detection using 832 kg of liquid xenon as target material. To understand the detector response to nuclear recoils, we performed a neutron calibration using a 252Cf source. In this presentation, we discuss the calibration setup and result. In particular we present the obtained scintillation decay time and scintillation efficiency. The MC reproducibility is also shown.
ASJC Scopus subject areas