X-Ray Multi-Energy Introscopy Systems with New Semiconductor   Scintillators
  Theoretical background and data on the ways of practical realization are presented, related to the problem of detection of dangerous organic objects (explosives, drugs, etc.) in the presence of other organic substances with atomic number differing by no more than 20-30%. For this purpose, multi-energy X-ray introscopy is used. It has been shown that the "weakest link" in the existing multi-energy introscopes used for safety inspection and medicine are detectors of ionizing radiation. In particular, critical is the type of scintillator used in the low-energy detection subsystem. Data are presented on design principles and properties of combined detectors based on a new type of semiconductor scintillators (SCS) -- $ZnSe(Te,O)$, with conversion efficiency of 19-22%, afterglow level less then $0.05 %$ after $10 ms$, and radiation stability up to $500 Mrad$. Results are given on the practical use of experimental samples of the low-energy detector subsystem based on the new SCS material in two-energy introscopes of the 4th and 5th generation. 
V.D. Ryzhikov, N.G. Starzhinskiy, S.V. Naydenov, E.K. Lisetskaya, L.P.   Gal'chinetskii, V.I. Silin