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The use of scattered radiation in the production of signatures for explosive detection has been studied. Signatures have beenmeasured and the spectral analysis of these using multivariate statistics has demonstrated that explosives within realisticenvironments can be recognised '. The problem remains of how to use this information in the time frame allowed by airportbaggage security checks. To address these problems we have developed a 'tuned' system approach. The energy-angle spacediagrams have been created and the areas containing the greatest information density in the presence of an explosive havebeen identified. A specially designed detector (CdZnTe) array has been built to match these regions. The array has beenused to identify explosives hidden within realistic case situations.Keywords - scattering, CdZnTe, energy-angle space, detector array 1. INTRODUCTION X-ray security and custom systems have been in use since 1898 but it was the advent of aircraft hijacks in the 1960's thatprovided the impetus for widespread use of such devices at airports. Since their introduction various developments havetaken place such as the folded detector array for a more complete survey volume of any article examined, the use ofdifferential attenuation measurements to classify examined materials as organic, inorganic or metallic and more recently theapplication of tomography or stereoscopic techniques to enable depth information to be encoded in the image. However, theability of the system to uniquely identify an energetic material embedded within a typical suitcase is poor and current |
