Team aims to develop nuclear detector using noble gases

Plans for a new radiation detector to help stop the illegal supply of nuclear materials could address the growing costs of current technology.

Researchers at Liverpool University are developing a device that relies on xenon and other noble gases instead of an increasingly rare type of helium used in some existing equipment to detect neutron radiation, as part of a €3.3m (£2.7m) EU-funded project.

The academics, working with other universities and commercial partners across Europe, plan to produce a prototype device to help catch smugglers and terrorists handling nuclear materials that could be used to make weapons.

The price of the helium-3 used in current detectors has gone up by a factor of 10 in the last few years, said Liverpool’s research leader Prof Christos Touramanis.

‘Helium-3 is a by-product of the nuclear weapons industry and, as people are not making more plutonium because there’s no need for it, the stockpiles are running out,’ he told The Engineer.

In existing detectors, neutrons collide with the nuclei of helium-3 atoms to produce light at a specific wavelength, which can then be used to identify the source of the neutrons via computer algorithms that analyse the light spectrum.

Touramanis said there were two novel requirements of the research: adapting the technology to work with other noble gases and turning it into a simple, rugged device for use in the field.

‘If you take a detector and just put some noble gas in you will not get out what you want. You need to play with the parameters of the operation [such as] the different wavelengths and amounts of light.

‘The second difference is that most radiation detectors, including those with helium-3, were made for laboratory use and so are not rugged enough for putting in the back of a van.

‘Also, between the detector itself and the computers you need to read it, you end up with something big and heavy that requires expert operators.’

The researchers want the final device, which will be integrated and assembled in Liverpool towards the end of the three-and-a-half year project, to comprise a modular system of small elements, including a simple traffic light-style indicator of whether nuclear materials are present.

Oxford University and Imperial College London are undertaking a similar project that is using the isotope lithium-6 in place of helium-3.