Energy dispersive X-ray diffraction spectral resolution considerations for security screening applications

Energy dispersive X-ray diffraction (EDXRD) is a very effective method for explosive and narcotic threat detection in baggage screening. The XRD profiles arise from the molecular interference when X-rays are coherently scattered by a substance. The accurate identification of the target material depends on the ability to detect and resolve the peaks present in the coherent scatter profiles. A high-energy resolution High Purity Germanium (HPGe) detector is therefore generally used in such type of systems. To evaluate the suitability of cost-effective room-temperature semiconductor detectors for next-generation baggage screening systems, an assessment of the minimal requirements for the system resolution is required. In this study a hybrid Monte Carlo code has been modified to account for the molecular interference function that gives rise to the coherent scatter signature. A model for a realistic response function for Cadmium Zinc Telluride (CZT) detectors is then used to convolve the spectral output. This simulation tool is then used to assess the system design features and their influence on spectral resolution.