  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.
