Scintillator-photodiode type detectors for multi-energy scanning   introscopy
  Results of experimental studies of detector arrays S-PD (scintillator-photodiode) and PRD (scintillator-photoreceiving device) used for X-ray digital radiography have shown that there exist further possibilities to increase spatial resolution of this system up to 2-3 line pairs per mm. Theoretical analysis and experimental studies show that the two-energy detection method not only allows one to detect organics on the background of metal, but also substantially increases (by 3-5 times) the detection ability of the system as a whole, especially if parameters of the S-PD pair are optimized, in particular, when ZnSe(Te) is used in the low-energy circuit. A possibility to distinguish, in principle, between substances with insignificant differences in atomic number has been theoretically proven -- by transition to multi-energy radiography. 3D-imaging has been realized using S-PD detector arrays. 
V.D. Ryzhikov, S.V. Naydenov, D.N. Kozin, E.K. Lisetskaya, A.D.   Opolonin, V.M. Svishch, T.V. Kulik