Microscopy and Analysis talks to Diamond Light Source chief executive, Professor Andrew Harrison, on future plans for the UK synchrotron.
Diamond has been up and running for a decade now; what does it offer researchers today?
Diamond is a national facility with 28 operational beamlines, and is free at the point of access for researchers from UK universities and industry. Traditionally researchers want to use X-rays to look at the atomic-scale structure of a material and find out its crystal structure; this is crucial to understanding function. And with our brilliant beams at Diamond a researcher can study structure in a fraction of a second. We are now moving away from looking at static materials 'post-mortem' to looking at how materials change during a reaction or physical transition; our X-ray brightness allows you to look at such dynamic changes much more quickly. So if, say, you want to study a catalyst that might be used in a car exhaust, you can look at real transformations in operando.
How else is Diamond being used now?
X-rays can form the basis of spectroscopy with, for example, X-ray fluorescence providing a very sensitive probe down to parts per million. Researchers are mapping the distribution of chemical elements within a material to sub-micron resolution. For example, life scientists investigating degenerative brain diseases can look at the correlation between abnormalities in brain tissue and the concentration of certain elements.
Metal composition of a sixth century Anglo-Saxon brooch found at Oakington, Cambridgeshire [Duncan Sayer]
Meanwhile in the physical sciences, researchers can find out which chemical elements are present, in what oxidation state, during a catalytic reaction. At the same time, 3D tomography at micron resolution is also important and very useful in many engineering problems when you wish to look at the microstructure of a composite material or alloy. We offer this under real operating conditions, allowing researchers to observe microstructure changes at sub-second timescales.
Who uses Diamond?
In any typical year we receive around 9000 user visits, resulting in published papers of which half are in the life sciences and half in the physical sciences. In the past, users were typically physicists with expertise in synchrotron techniques but this has changed. Scientists are becoming increasingly aware of how synchrotron radiation can be applied to their research so we get researchers coming from a massive range of fields, even archaeology and palaentology. But even in traditional areas, such as structural biology, more and more researchers are coming to us.
Ultrahigh resolution microscopy at Diamond Light Source. [Diamond]
Which new scientific fields are accessing Diamond?
Cultural heritage is a small but growing area and we are trying to build bridges towards people in museums, for example, that wouldn't necessarily think to use X-rays. We are also seeing more and more work on biomaterials. X-rays were traditionally used to look at the structure of crystalline materials or to image objects with a significant contrast in absorption. However, synchrotron X-rays are not only bright and able to be focused to a fine point, but are also highly coherent. We exploit this coherence to bring out contrast in different regions of a sample where the X-ray absorption is actually very similar. Take the tissue in a knee joint; everything is very light and absorbs X-rays to a similar degree. However, we can measure changes in the phase of the coherent X-ray wave as it passes through the tissue; so the bottom line is we can now image soft materials much more powerfully.
Are there other research growth areas you are excited about?
Environmental and Earth sciences; we've always had the hard core users that look at rock physics, but more and more of these researchers are using X-ray absorption spectroscopy at Diamond. For example, a researcher might want to measure the parts per million levels of toxic elements taken up by plants through contaminated water supplies. Likewise, researchers in the nuclear industry track low quantities of radioisotopes; X-rays provide a very sensitive, non-destructive way of doing this.
At Diamond we have emerging technologies, such as additive manufacturing, starting to apply X-ray analysis. Take a titanium component; instead of using a lathe to carve out a component from a titanium block, the component could be additively manufactured using laser deposition. Researchers can now understand how the structure of the material differs according to the manufacturing method. As more and more new areas of science and technology emerge we expect X-ray synchrotron radiation to be applied to them.
X-ray tomogram shows detail of hoverfly's five eyes; imaged at the Diamond-Manchester branchline [Taylor et al/Lund/Diamond]
In 2016, Diamond had its first users at the electron Bio-Imaging Centre with cryo-electron microscopy and now we have the electron Physical Science Imaging Centre with high resolution electron microscopy for materials science. Why bring in these methods now?
Thanks to developments in direct detectors, we've been seeing a revolution in cryo-electron microscopy. Our Life Sciences director, Professor Dave Stuart, wanted researchers to use cryo-EM as a complementary technique for structural and cellular biology at Diamond (see 'An eye on electrons'), so we brought this in. We've seen similar developments in the physical sciences, and our collaboration with Johnson Matthey and the University of Oxford recognised that for non-biological materials, a combination of X-ray and electron microscopy analysis provides complementary views.
How do you ensure that these different methods are used seamlessly?
Users can prepare samples in a standard way and move the samples from a beamline to an electron microscope, combining information from the different methods; we have also co-located expertise to support this. Crucially, not every single university has, for example, a cryo-electron microscope, so it makes sense for researchers to be able to access a pool of technical expertise in a centralised facility that runs 24 hours a day. Right now the number of high-end operators that can fully exploit these microscopes is limited, so it makes sense to have this facility.
Given the cutting-edge analytical facilities at Diamond, is data-handling an issue?
Data-handling is a tremendous challenge and we have devoted considerable resources to ensuring we have enough storage capacity for analysis. But in the mid- to long-term I don't think any single laboratory should take on this issue alone. We need to pool resources and confront the problems such as storing, transporting and analysing the vast quantities of data together. We will provide the in-house facilities to allow our users to rapidly analyse data at the time of experiment, but the data associated with post-experiment analysis is vast; alternative solutions are needed. Given this, we are looking at partnerships across Europe. This isn't something we should tackle alone in the UK, every country with a research base has this issue and we want to partner with other countries that have these challenges.