Neutron microscope could aid speedier measurements

British engineers have unveiled a neutron microscope that could enable scientists to make measurements up to 30 times faster than existing UK facilities.

The £4m Polaris instrument, which was installed at the Science and Technology Facilities Council’s ISIS neutron research centre last Friday, could help analyse molecules and materials for developing drugs and electronic components.

The machine uses a larger array of neutron detectors than previous technology to examine how a substance deflects the high-speed particles and so study its structure at the nanometre scale.

Dr Stephen Hull, lead scientist on the project, said: ‘Polaris will allow us to make measurements up to 30 times faster than we could before and follow chemical reactions in real time, opening up new areas of science.’

Possible uses for Polaris include: improving the performance of laptop and mobile phone batteries; understanding how drugs interact with molecules in the body responsible for diseases such as Alzheimer’s; and developing magnetic materials that can be used to make new forms of computer memory.

David McPhail, one of the STFC engineers who helped design and build the instrument over five years, told The Engineer that one of the biggest challenges was fitting all the detectors into the machine, which sits in a 20m3 vacuum tank.

‘When the neutrons hit the sample they go in all directions and often the scientists have to move the detectors around to try and catch them. With this larger coverage, the neutrons come to them.’

The detectors effectively turn the neutrons into photons that are transmitted through ‘code-paired optical fibres’ that are then picked up and converted into electronic signals.

‘We had to put all these detectors into a very small space [and] we had to fit in hundreds of kilometres of optical fibre. If you bend them too tightly you lose signals through the walls of the fibres so you have to keep them quite straight.’

To do this, the machine’s design was divided into different modules and simulations used to determine the ideal position of the detectors within each one.

‘I was asked to place the detectors along these lines that were often way, way back where there was no space so it was a constant battle between the engineers and scientists,’ said McPhail.

Because each detector also had to be pointing towards the oncoming neutrons they had to be made in many different shapes, so the team used 3D CAD modelling and laser sintering additive manufacturing to cheaply produce the many different molds required.