DISTINGUISH: Detection of explosive substances by tomographic inspection using neutron and gamma-ray spectroscopy

There is a need for inspection systems that are able to detect explosives (or drugs) hidden in for example luggage. These systems are most efficient if they can inspect the object without having to investigate by hand. e.g. a person does not have to search each piece of luggage or container. Explosives almost universally comprise hydrogen, carbon, nitrogen and oxygen is different ratios. A system that will detect elements like these is based on sending a beam of neutrons into the system. The different elements will emit gamma rays of different energies which are unique to the isotopes concerned. These gamma rays can be measured accurately with a germanium gamma-ray detector and hence the amount of each element determined. This information can then be used to determined the ratios of the four elements and hence whether explosives (or drugs etc.) are present. By using modern technology the germanium detector can also be used to make an image of the object under investigate, similar to an airport baggage scanner. In this case the gamma-rays and scattered neutrons will be detected simultaneously to make a clearer image. By the end of the project we hope to have demonstrated in the laboratory that these ideas are effective and to determine the potential sensitivity.