High dynamic range measurement of CdWO4 afterglow

The notable feature of cadmium tungstate (CWO) is quite long (similar to 14.5 mu s) 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 similar to 0.5 MeV, 6 mu s 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.