MgWO_4-A new crystal scintillator

摘要

Magnesium tungstate (MgWO_4) crystals of～1 cm~3volume were obtained for the first time using a fluxgrowth technique. The crystal was subjected to comprehensive characterisation that included room-temperature measurements of the transmittance, X-ray luminescence spectra, afterglow under X-rayexcitation, relative photoelectron output, energy resolution, non-proportionality of scintillationresponse to y-quanta, response to a-particles, and pulse shape for y-quanta and a-particles. The lightoutput and decay kinetics of MgWO_4were studied over the temperature range 7-305 K. Under X-rayexcitation the crystal exhibits an intense luminescence band peaking at a wavelength of 470 nm; theintensity of afterglow after 20 ms is 0.035. An energy resolution of 9.1 for 662 keV y-quanta of ~(137)Cswas measured with a small (≈0.9 g) sample of the MgWO_4crystal. The photoelectron output of theMgWO_4crystal scintillator is 35 that of CdWO_4and 27 that of Nal(T1). The detector showed pulse-shape discrimination ability in measurements with a-particles and y-quanta, which enabled us toassess the radioactive contamination of the scintillator. The results of these studies demonstrate theprospect of this material for a variety of scintillation applications, including rare event searches.