A prototype for explosives detection based on CXRS (coherent x-ray scattering) has been developed within a Philips research project, funded in part by the German Ministry of the Interior (BMI). The system uses primary x-radiation from a high power x-ray tube (160 kV) to generate coherent scatter which is measured at a small fixed angle in the forward direction. Scatter spectra from many volume elements ('voxels') of a piece of luggage are accumulated with an energy-resolving multi-channel germanium detector. For most military and industrial explosives, the scatter spectra exhibit characteristic diffraction peaks corresponding to their polycrystalline structure. The technique thus lends itself to a fully automatic inspection process. The system is to be tested and refined during a test phase at Hamburg airport. Its principle, geometry and design are presented along with some results concerning CXRS material selectivity.
"CXRS explosives-detection airport prototype", Proc. SPIE 2936, Physics-Based Technologies for the Detection of Contraband, (6 February 1997); doi: 10.1117/12.266268; https://doi.org/10.1117/12.266268