Diamond discoveries

Kerry Taylor-Smith left Lab News Towers and ventured into the heart of the Oxfordshire to discover what’s new at the Diamond Light Source - and finds rusty hedgehogs, volcanic diamonds and gold art

The Harwell Science and Innovation Campus is pretty intimidating; not only does it cover a massive area in heart of Oxfordshire, but it’s home to some of the most amazing scientific institutions in the UK – the UK Atomic Energy Authority, the Rutherford Appleton Laboratory and the European Space Agency to name but a few. But the most domineering sight on the sprawling campus has to be the Diamond Light Source – a 45,000m2 doughnut-shaped building which hosts some of the most intrusive scientific investigations currently underway.

Using synchrotron light – which can be as much as 100 billion times brighter than the sun – scientists are able to probe samples in incredible detail, looking at the nature of chemical compounds and how chemicals react, what happens when the Earth’s early conditions are recreated and how materials behave under the stress and strain of everyday life.

The reason for my visit to the campus was to see what’s been going on at Diamond since it opened its doors in 2007: Dr Claire Pizzey, an industrial liaison scientist, showed me around the facility and some of the beamlines currently in use.

While walking around the 561m ring, Claire and I nipped into a few of the support laboratories – jam-packed with state-of-the-art equipment. These labs are available for those using the synchrotron, or those who just need a place to carry out some experiments. Scientists and industry can hire out the labs to undertake experiments that they can’t do in their own labs, and since Diamond is one of the most powerful synchrotrons in the world, people flock from far and wide to make use of the opportunity.

“The aim of Diamond is to help scientists figure out why – why something is arranged the way it is, why it works this way and not that way for example,” Claire explained. “And not everyone – especially industry – has access to the equipment available here, or the know-how to do the experiments so we try help them as best we can by offering them time in our labs or working on their samples for them.”

Diamond is able to generate light from infrared to x¬-ray by firing low energy particles from an electron gun which are accelerated to very high speeds through a series of particle accelerators – the linac, the booster synchrotron and the storage ring. The ring is actually a 24-sided polygon containing dipole magnets to steer electrons – which are moving at near the speed of light – around the ring. As they pass the magnets, the electrons lose energy in the form of incredibly bright synchrotron light which can be channelled out into the beamlines or experimental stations. Insertion devices – or magnets – on the straight parts of the ring cause the electrons’ path to wiggle, which gives a more intense and tuneable light for experiments.

Each beam can be optimised for a different experiment – for example, earth, materials or environmental science – and the ring is colour-coded, split into 12 imaginary sections with each colour corresponding to a different type of experiment.

The first beamline I visited was I22, the non-crystalline diffraction beam which uses small angle x-ray scattering (SAXS) – with an angular range of up to 1° – to look at the structural and dynamic information provided by a sample. A high brilliance insertion device creates high energy x-ray beams and allows structural investigation of materials under extreme conditions. All the x-ray experimental stations are lead-lined to protect users from the potentially harmful beams.

I met with principal beamline scientist Nick Terrill who explained that SAXS is being used to look at liquid crystals, biomaterials and polymers. Unfortunately we weren’t able to go in and look at this beamline closely as it was in use, but Nick explained that it has recently been used to investigate the kinetics and shape of colloidal iron in the environment, in particular at green rust.

“This type of rust forms in wet conditions with no oxygen, like disused mines,” said Nick, “Once it comes into contact with air it goes orange, like the normal rust we see.”

The green rust looks like hedgehogs with fibrils – one sphere on top of another – growing up like spines, explained Nick.

“This green rust can act as a barrier, trapping selenium and chromium in contaminated water,” Nick said, “It’s hoped that one day we might be able to use it as a filter to remove toxic elements from the water, particularly in places like India where most of their drinking water is contaminated.”

Toxic and radioactive species are rendered insoluble and immobile by the green rust, which prevents contamination from spreading and reduces the species’ bioavailability.

Having learnt more about rust than I thought it possible to know I was whisked off to B22, the infrared microspectroscopy beamline which uses bending magnets to generate infrared beams. This beamline is much less damaging than the x-ray beams generated in I beamlines – you can even put your hand through the beam with no detrimental effect – and I was able to sit in the experimental hutch while a team of scientists prepared it for the next day’s experiment.

The day before my arrival, the beamline was used by a group of scientists studying diamonds from volcanoes. “They weren’t the shiny ones you might expect to see in an engagement ring,” said Gianfelice Cinque, the principal beamline scientist on B22, “They were black and grey, and the investigating scientists were interested in how and why they formed.”

The beamline has also been used to examine paintings from Catalonia where a lot of gold and silver leaf was used in composition. The investigating scientists were interested to find out what the paint was made of, and how the paint was layered to give the overall effect. Gianfelice explained that only a small fragment of the painting was required to testing, so the paintings could remain in their galleries largely undamaged.

“I was ushered to the end of the room to sit in front of several computer screens showing webcam images of the inside of the hutch while the team finished their final checks. After everyone was out, principle investigator Matthew Rowles set the countdown going – including flashing blue lights and sirens”

“This beamline is also used to look at medical samples, for example cancerous cells and how they react to chemotherapy,” Gianfelice said, “We hope one day to be able to test a small amount of blood to see how it reacts to chemo before dosing patients up unnecessarily.”

The final beamline I visited – and the first to have an observable experiment underway – was I12, the JEEP (Joint Engineering, Environmental & Processing) beamline. Here I met a group of scientists from Australia who were conducting an experiment to find new ways of refining titanium from the ore.

After a quick peek into the experimental hutch I was ushered to the end of the room to sit in front of several computer screens showing webcam images of the inside of the hutch while the team finished their final checks. After everyone was out, principle investigator Matthew Rowles set the countdown going – and what a countdown it was, in true Hollywood style it included flashing blue lights and sirens – quickly ran around the hutch one last time to check everyone was out before the experiment officially started.

Inside the storage ring: a highly complex system of magnets and cooling equipment

Matthew told me that they’re doing an electrolysis experiment – passing a current to bring about a chemical reaction – to refine titanium and are hoping to figure out what happens to the anode in the reaction. He explains that they’re passing x-ray beams through a furnace containing an aluminium crucible which contains calcium chloride to do this.

“In the melt is an anode of titanium oxide and cathode of TiO2-x – it’s a bit different to the normal cathode,” he said “We’re interested in looking at titanium electrolying so the cathode turns to titanium but the problem is the anode, so we’re doing an experiment to look at the structure of the anode and how that changes as a function of time.”

Titanium is currently produced by the Kroll method, which is messy, complex and wasteful - the hope is to eventually develop a process to make the metal more cheaply. The team consists of seven members who share the 24 hour workload – the team have hired out the beamline for a few days, and their experiment has to be finished in that time. Since the experiment was to run for a few hours I had to make my excuses and head back to Lab News Towers but I’ll be keeping a close eye on the science press for news of the team’s results.

The Diamond Light Source is amazing – not only does the sheer size of the building take your breath away – but there was so much to take in and with such a large range of experiments taking place each day, it’s clear that no two days at Diamond are ever the same. As Claire said: “It really is an exciting place to work, and you learn something new each day.”

Want to know more about how the Diamond Light Source works? Check out the Diamond playlist at www.youtube.com/labnews