LOW-ANGLE X-RAY SCATTER FOR EXPLOSIVES DETECTION - A GEOMETRY OPTIMIZATION

A geometry has been established for a low angle X-ray scatter (LAXS) s ystem for the detection of sheet explosive in passenger baggage. The e nergy dispersive diffraction profiles of two typical explosives, PE4 a nd Semtex, have been investigated under a wide range of geometric cond itions. A scatter angle of 5 degrees and a slit collimation arrangemen t with an angular resolution of 20% has been found to satisfy the requ ired criteria of well-defined, high intensity diffraction profiles at the sufficiently high energies necessary to penetrate baggage items. A n investigation of typical benign suitcase contents under the optimal geometry show in general broad low-order diffraction profiles in contr ast to the highly characteristic diffraction from the explosives. Real time measurement of explosives show that characteristic diffraction p rofiles can be measured in times as short as 0.1 s although a large st atistical uncertainty results. Copyright (C) 1997 Elsevier Science Ltd