High dynamic range measurement of CdWO₄ afterglow

The notable feature of cadmium tungstate (CWO) is quite long (∼14.5μs) decay time of its brightest scintillation component. In this paper, the technique and results of high dynamic range measurements of CWO afterglow are discussed. Samples were irradiated by bremsstrahlung of a ∼0.5 MeV, 6μs electron beam. The afterglow tail of the scintillation curve was measured down to the relative amplitude <10⁻⁵. At such intensities, a parasitic fluorescence of a photomultiplier essentially contributes to the total signal. The CWO light emission dynamics is determined by known scintillation components to at least 10⁻⁵ level. Constraints on the existence of a possible slower fluorescence component are discussed.