Radiation Detectors Scintillator-Photodiode on the Base of A2B6 Crystals for Application in Homeland Security and Medical Equipment

We have studied comparative parameters of different scintillators: CsI(Tl), CdWO₄, ZnSe(Te), ZnSe(Te,O) for dual-energy radiography applications. Detectors of the scintillator-photodiode type were obtained on the basis of CsI(Tl), CdWO₄ and ZnSe(Te) crystals, and their comparative study was carried out, aiming at their use in X-ray multi-energy tomography. Because of their low afterglow level (10 ppm after 10 ms), CWO and ZnSe crystals are preferable for this application. Our experiments have demonstrated a possibility for significant distinction between explosives and safe organics, so as between soft and bone tissues. Direct image reconstruction of biological objects (bones) and customs control objects (bags with dangerous items and substances) was obtained by the used method of dual-energy radiography. Theory predicts that, provided the energy selectivity of the detection circuit is improved, separate detection of substances with difference of 5-10% in density and effective atomic number can be possible.