2011 MRes projects
- The development of a backscatter X-ray system for cargo & vehicle screening
- Self-organisational behaviour patterns in crowds within the context of crime at bus stops
- Hippo Foraging and Poaching Using Agent Based Modelling
- Obstructions and Requirements for Coercion Resistance
- Using Semiconducting Metal Oxide Gas Sensors to Detect Explosives - A Feasibility Study
- Speed Up Effects in Security Procedure on Delhi Metro Rail : Implications for Queuing Theory and Rail Security
- 'Have Gun - Will Travel’: The Movement and Re-use of Firearms in England and Wales
- Time-of-Flight X-Ray Compton Scatter Imaging for Cargo Security: A Preliminary Study
- Is High Performance Liquid Chromatography Analysis a Useful Addition to Current Geo-Forensic Analytical Techniques?
- A Comparison of the Spread of Extreme Protest Behaviours Through Two Activist Networks
- On the Feasibility of Using Probably Approximately Correct Search Over BitTorrent Tracking Information
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Time-of-Flight X-Ray Compton Scatter Imaging for Cargo Security: A Preliminary Study
22 March 2013
Nick Calvert
Cargo security is of increasing global concern due to the large volume of sea based freight that requires securing. Inefficient screening processes leads to delays in the delivery of goods leading to significant losses. Current screening methods rely on low energy X-Ray backscatter and high energy transmission imaging systems, restricted to providing two dimensional images. This thesis introduces the concept of Time-of-Flight (ToF) x-ray Compton scatter imaging (CSI), an imaging modality that utilises ToF information to acquire three dimensional scatter images. A mixture of simulation and experimental work was undertaken in order to assess the feasibility of such an imaging system by considering four key aspects required for a ToF CSI system. Monte Carlo simulations were performed to generate 4 MeV and 6 MeV spectra and to suggest optimal target design for a possible x-ray source. Optimal target design was found to be dependent on a number of factors relating to photon and electron yield, and photon energy. The problems of attenuation and multiple scatter were considered by performing Monte Carlo simulations of a cargo container and measuring the ToF of photons undergoing Compton scattering. ToF simulations suggested multiple scatter reached 30% for the geometry simulated and led to blurring in the ToF measured. Attenuation led to fewer counts from more distant objects, but penetration was calculated to be at least 20 cm in plastic. The timing response of a new silicon detector was experimentally compared to that of a traditional detector ,and was found to be up to 4 times slower and therefore not suitable for ToF imaging. This thesis shows that ToF CSI has potential, however future experimental work is required to verify the Monte Carlo simulations undertaken.
