Neutron beams offer security imaging solution
A technique that promises clearer images of baggage and cargo scans at airports and other transport hubs is being developed by a University of Huddersfield researcher in the UK.
Physicist Simon Albright is investigating the use of safer neutron sources that generate minimal radioactivity for the imaging technique called pulsed fast neutron analysis. He is currently completing his PhD in the University’s International Institute for Accelerator Applications (IIAA).
Most x-rays, currently used for probing cargoes, produce two-dimensional images in which concealed items can be hard to detect. But, after computer analysis, an image produced by neutron beam scanning can be exceptionally clear and easy to interpret.
‘All the clutter, all the clothes and shoes, are taken out of the image and the operator sees only the possible threats, such as drugs or bombs,’ said Albright.
It is vital that neutron beam scanning become a practical possibility, he added.
‘At the moment we just don’t have good enough image recognition. With current technology, if someone brings in a container that mostly consists of potatoes, for example, you would not be able to tell that in the middle they have hidden a huge block of cocaine.’
However, although the theory of pulsed fast neutron analysis is well established, the challenge is to produce compact, safe scanners. Devices known as sealed tube neutron generators do exist, in the form of metal tubes that require the use of an isotope of hydrogen named tritium. But its radioactivity means that strict controls are necessary.
‘You can’t have these sitting around at a port, running through a few hundred of them a year. They would have to be stored in a very secure warehouse, which is simply not practical,’ Albright said.
Albright’s PhD project investigates the use of safer neutron sources that generate minimal radioactivity. Oxygen, lithium and beryllium are among the safer alternatives to tritium. Albright is also examining lower and more variable energies of beam, so that compact, cost-effective neutron scanners would become a more practical possibility.