Awaiting Public Project Summary

X-ray screening is high priority for securing borders from the influx of firearms, narcotics, and contraband. The ability of an x-ray screening system to detect photons attenuated by dense cargo directly affects the radiographic image quality that an operator uses to identify such illicit material. When screening cargo and vehicles, high-energy high-dose pulsed linear accelerators are used to generate the x rays. The detection package integrates the signal over the duration of a single pulse and this forms the basis of each pixel value in the image. However, with no means to reject low-energy photons scattered into the detectors or electronic dark current, the signals include a large degree of noise that distorts the final radiographic images. The technological advances in recent years and the exploitation of spectroscopic techniques present an opportunity to utilise novel detector material and off-the-shelf fast electronic components to identify individual photons. This will vastly improve the performance of screening systems and increase image quality, particularly in areas of high attenuation. To this end, this project seeks to investigate new detector material, design, construct and test a prototype detection system capable of photon counting in such high x-ray flux environments. Detector characterisation and design will be carried out at the University of Manchester. Experimental investigations will require the use of the new Compact Linac facility at Daresbury laboratory, capable of producing low-dose x-ray pulses so that algorithms to control the detection package can be developed and the limitations obtained. The detection package will then be used at Rapiscan Systems facility at Stoke using a field-ready linac to prove its capabilities.

There are many examples when taking a transmission X-ray image where correct interpretation of that image would benefit from being able to correctly identify and characterise the materials that are present. If the object is anything other than a thin sheet the ability to isolate and characterise materials in 3D space becomes important. An example where this ability could transform the use of X-ray imaging is security. We will target four areas of application: 1. Explosives and weapons - Weapons and explosives illegally imported into the UK are used in violent crime and terrorist activities. Detection and identification of these items at UK points of entry is a priority for the UK Government and is key to reducing crime and disrupting the UK based terrorist threat. 2. Illicit drugs - The use of illicit drugs costs the UK £15.4 billion per year, and has massive implications for public health due to physical harm to users, drug dependencies, and the effect on families, community and society. The UK Government implemented a new strategy in 2010 with a main aim of restricting the supply of drugs, and the Home Office CAST is very active in developing new technology for the detection of drugs and other contraband substances. 3. New psychoactive substances (NPS) - Similarly NPS or 'legal highs' can carry serious health risks. Typically the chemicals they contain are not endorsed for human consumption and the resulting effects are unknown and unpredictable. In a recent review, the UK Government outlined an action plan for dealing with the growing NPS problem. Central to the action plan was for the UK Border Agency to be able to identify shipments of NPS entering the UK so they can be seized and destroyed. 4. Counterfeit drugs - The sale of substandard and counterfeit pharmaceutical products accounts for 10% of global trade and is affecting many countries (mainly developing countries but also developed countries to a lesser extent), causing serious downstream expense, resource shortages and detriment to health. One of the main aims of the UK Medicines and Healthcare Regulatory Agency (MHRA) is preventing counterfeit drugs entering the supply chain with more responsibility being put on the wholesaler to ensure drugs are sourced from legitimate suppliers and to report any suspicious activity. The proposal is to deliver an X-ray imaging and analysis system that is capable of non-invasively identifying explosives, illicit drugs, legal highs and counterfeit pharmaceuticals within baggage, packets, boxes and other containers. The system will provide high resolution transmission images as well as the analysis and position of selected materials within a larger 3D volume (e.g. a packet of illegal drugs within a parcel containing other items). Central to this project is a novel X-ray diffraction technique developed at UCL with Home Office and Department of Homeland Security backing, which has been proven to be highly effective for this purpose. This will now be enhanced such that rapid, full 3D capability will allow larger, more complex containers, as are found in real-world applications, to be analysed.

The United Nations (UN) have announced that "With more than 30,000 foreign terrorist fighters from some 100 countries around the world, terrorism is a global threat requiring a comprehensive and unified response." This statement followed a spate of recent terrorist attacks, including those in France and Germany (July 2016), and a growing sense of global uncertainty in the western world. Promoting improvements to the identification and location of metallic threat items is an important aspect of the unified response and is an area where engineering and science can make a significant impact. Improvements in metal detection (MD) technology also provides wider benefits to the humanitarian cause of clearing landmines in developing countries. Wider benefits exist for the technology being transferred to MD companies developing devices for the non-destructive testing (NDT) of materials for safe structures, ensuring food safety, improved scrap metal sorting, as well as in medical imaging and archaeological searches. Of course current metal detectors do find highly conductive objects and their simple design (and portability) has made them a highly cost effective modality for safety and security applications. Unfortunately, current technology is not able (or has limited capability) to distinguish between objects of different shape and materials of objects and can only detect objects within a small stand-off distance (or buried depth). This proposal is aimed at overcoming these drawbacks through an interdisciplinary approach to improving MD technology, combing engineering, mathematics and scientific computation. Our hypothesis is that the response of metallic items in low frequency electromagnetic fields can be accurately described using a tensor based approximation. To test this hypothesis, we will develop a complete laboratory demonstration of our MD approach. This includes the following novel aspects: an efficient and adaptable software that can compute tensor coefficients for in-homogeneous objects, an algorithm for identifying different targets from field measurements with embedded uncertainty quantification as well as enhancing MD measurements by building new coil arrays based on optimised coil design. The goal is that our complete software and measurement package will lead to a step change in MD.