Fabrication of an alpha particle counter: spin coated films of synthesized nanocrystalline cadmium tungstate powder

Background: CdWO4 is a scintillator with some unique properties. For example, high density, thermal and chemical stability and so on. Different applications of this scintillator such as X-ray scintillator has been investigated thoroughly so far. However, there is limited number of studies reporting the characteristics of CdWO4 as an alpha counter. Materials and Methods: The CdWO4 powder was synthesized by a simple co-precipitation method. Then, the CdWO4 films with different thicknesses were prepared by spin coating method on glass substrates. The CdWO4 powder and films were characterized by X-ray diffraction, photoluminescence, scanning electron microscopy, Fourier transformed-infrared spectroscopy, and ion beam induced luminescence. Finally, the response of samples with different thicknesses was measured using a 241Am alpha source with 1860 Bq activity. Results: The analyses revealed that the nanocrystalline CdWO4 with about 30 nm size was successfully synthesized without any impurity. Besides, the CdWO4 films had the same luminescence emission peak characteristics as CdWO4 powder had. Conclusion: It was observed that the sample with 2.9 mg/cm2 thickness had the best counting efficiency (over 2π geometry) among the others.