The Na2W2O7 crystal: a crystal scintillator for dark matter search experiment

Abstract

A single crystal of Na 2W 2O 7?(NWO) was grown by a low-thermal-gradient Czochralski technique (LTG-CZ). The scintillation properties of the crystal were evaluated for the first time as a potential material for dark matter search experiments. The luminescence and scintillation characteristics of the crystal were studied at room temperature and low temperatures by using a light-emitting diode (LED) and a 90Sr beta source. The luminescence and scintillation light yield at 10?K were significantly higher than those at room temperature. The crystal showed higher light yield at 10?K than a CaMoO4?(CMO) crystal. The decay time of the crystal was investigated at temperatures between 10 and 300?K. The sensitivity to spin-independent weakly interacting massive particle-nucleon interactions based on 10?kg (2?months) and 50?kg (12?months) data for the NWO crystal detectors was estimated by a simulated experiment using the standard halo model. The luminescence, scintillation, and sensitivity results revealed that the NWO crystal is a promising candidate for a dark matter search experiment in the near future. (c) 2018, The Author(s)