Diamond Light Source: Just call it The Eureka Doughnut

Abstract: The DLS is a bit like the LHC, except it works…

“Sure the DLS is a VIP, but it’s certainly no LHC.” My wife shook her head rather sadly at my pathetic attempt to introduce a bit of pop culture into the realm of physics. She was right. All I had succeeded in doing was making a comparison between two very important particle-accelerators (VIPs) sound like a rap-off between a couple of boy bands.

It’s hard to argue that CERN’s Large Hadron Collider (LHC) hasn’t hogged most of the limelight in the recent study of particle physics – it’s big, really big, very expensive and, amongst other things, is apparently looking for all the answers of the Universe – but they’re hidden in something particularly small called, rather humbly, The God Particle.

As such the LHC holds all the ingredients of a good story: power, mystery, money, and, depending on who’s telling it, mayhem – with the theorized side effect of creating a black hole, into which we’re all going to get sucked and killed.

Whereas some of this is true, some is greatly exaggerated and some of it is pure nonsense.

What is a good story, though, is that while attention has been drawn to the LHC, another particle accelerator – Diamond Light Source – has been quietly getting on with the job. And “job”, here, is the operative word.

This Diamond works wonders

Diamond Light Source – or “Diamond” as it is affectionately known by those who work there – is, like the LHC, a particle accelerator, but it’s totally different.

First, there’s the size. Although they both fire particles around a giant circular structure, the circumference of Diamond’s accelerator is 561.6m – just over half a kilometre – whereas the LHC’s is 26.6 kilometres.

Secondly, Diamond is easy to see – it sits rather demurely next to other buildings that make up the Harwell Science and Innovation Campus tucked away near the town of Didcot, in Oxfordshire. The LHC, on the other hand, is hidden 175 metres underground, and it straddles the border between France and Switzerland.

Thirdly, whereas the LHC fires protons and ions around its circular collider tunnel and smashes them together to see what’s inside, Diamond fires electrons around a circular storage ring and then bleeds off tiny beams of the intense light produced to examine the behaviour and structure of different types of matter.

And it’s this use of the accelerator that defines the fourth, and most fascinating, difference between the two: whereas the LHC will, hopefully, go a long way toward clarifying key theories of physics, Diamond has very real practical applications across virtually all spheres of science.

The science behind Diamond

Although the science behind Diamond is incredibly technical, it can be explained with the simple analogy of a car: when electrons are produced and fired around the large circular storage ring, they travel its circumference about half a million times a second. Just as the tyres of a car travelling rapidly around a tight, circular circuit will protest by producing a squealing noise; electrons protest by producing intense light – called synchrotron radiation.

This electromagnetic radiation is across a wide spectrum and includes x-rays, UV, infra-red and visible light and can be used to examine the behaviour and structure of all manner of matter, from viruses and human cells to metals used in the manufacture of aircraft.

The observations are made in “beamlines”. These are experimental stations attached to the storage ring. Essentially they open up a window into the storage ring, tap off some of the intense light, filter it, focus it, and then direct it at whatever they need to examine. The resultant scattering of light is then interpreted to give a picture of what is happening inside the sample.

Numerous applications

Claire Pizzey, an industrial liaison scientist at Diamond, is only too happy to list some of the numerous applications that have benefited from this technology: designing new materials, investigating the properties of chemicals and examining the structure of viruses.
As such, it has been used in the fields of chemistry, earth science, environmental science, physics and materials science, as well as life sciences. In fact, 40 per cent of research done at Diamond falls under life sciences.

And if you want specific examples, Pizzey points to one of the most critical components of human health: medicines. “The route to modern drug discovery is through the use of a process called ‘structure-based drug discovery’… and it heavily involves the use of synchrotron radiation,” she explains.

In fact, the entire life cycle of a drug can be studied by Diamond, from examining the structure of a component compound or the most successful system to deliver that drug – through to examining competitor drugs for evidence of patent infringement.

With 18 beamlines fully operational and another four under construction to try and meet the demands for the insights Diamond can deliver, there are, according to Pizzey, “lots of little breakthroughs happening every day that lead up to bigger breakthroughs”.

I thought this deserving of another analogy to explain the importance of the Diamond Light Synchrotron to my wife, this time steering clear of cars: “It’s like a giant eureka doughnut.”

She shook her head. I must be losing my touch.

Originally published in Elements, 3 March 2012