13. May 2015
Research geared towards the futureResearch Using Synchrotron Light Large Research Facilities Materials Research Micro- and Nanotechnology SwissFEL
Interview with Gabriel Aeppli
Gabriel Aeppli has been head of synchrotron radiation and nanotechnology research at PSI since 2014. Previously, the Swiss-born scientist set up a leading research centre for nanotechnology in London. In this interview, Aeppli ex-plains how the research approaches of the future can be implemented at PSI's large research facilities and talks about his view of Switzerland.
The main problem with today's electronics is its high energy consumption. A common comparison is the fact that information systems (IS) produce more CO2 than the aviation industry. Someone once told me that the energy consumption involved in a somewhat complicated Google search is similar to that of making toast. IS energy consumption is increasing exponentially because too much of that energy is still being converted into heat. The energy can be converted into information or heat – and currently it's mainly heat.
And how can this problem be addressed?
The development of new materials is a potentially important step towards the future here. For instance, I research materials that, electrically speaking, behave differently on the surface than in their bulk. They can be metallic on the surface and insulating on the inside. In the long run, this opens up application possibilities for thin nanoelectric components that conduct electricity very well and do that with a very low degree of heat loss. In the research on existing electronics, it is essential to identify flaws, i.e. to see where energy is lost. You have to ask questions like: What happens in an integrated circuit if a transistor is switched on? How do the electrons and the atoms move?
So the path leads to ever smaller components?
We need to understand how electronic components work in detail. Research is increasingly being conducted in the nanoworld and examining how entire units and systems work over time. We see this trend across the board in research, from biology to micro and nanoelectronics. It is no longer merely about single-phase materials. Over the next few years, we will increasingly start examining biological cells or nanoelectronic components in action.
This requires research facilities of a suitable level, of course.
The Swiss Light Source SLS already produces cutting-edge results. However, the new x-ray laser SwissFEL, currently under construction, is a major step for PSI – as is of course the upgrade of the SLS, which, by the way, was also adopted in the Swiss Roadmap for Research Infrastructures 2017–2020.
What will be different about the future SLS compared to today's machine?
The future SLS will have a considerably higher brilliance than the machine currently in operation. This will essentially be achieved by reducing the size of the components – i.e. mainly the magnets – in the accelerator ring, which will enable the beam to be tuned more precisely, leading to a stronger focusing of the electrons. This change will increase the brilliance by one to two orders of magnitude. Such a reduction in the size of the components is the direction in which ring accelerator development is currently heading worldwide.
And what possibilities does SwissFEL offer future research?
The major possibilities of SwissFEL stem from time resolution in the femto-second range and also from the concomitant avoidance of radiation damage. A continuous light source damages the sample over the course of time. In the case of SwissFEL, the photons hit the sample quickly and simultaneously, meaning that they arrive and disappear again before the damage can take effect.
So the sample doesn't even notice...
Precisely. The sample is destroyed or at least seriously damaged, but only after the light has passed through it. This means that to study a process over time, identical copies of a sample that you examine throughout the process stages need to be available. SwissFEL is particularly useful for biological or chemical questions as you can produce exact copies of relatively complex systems. It's a bit trickier in engineering; no two transistors are ever exactly the same.
So you could say that PSI's large research facilities keep on developing.
Yes, and that's essential. Take the example of neuroscience. Here, the spatial resolution you need to understand how the brain works and is constructed from start to finish simply isn't sufficient yet. Research at PSI could help improve the existing models of the brain. The ultimate goal would be to observe processes in the brain in action, too. The details of this remain to be worked out, but X-ray based functional imaging would definitely have impact on this topic which has great clinical and social relevance.
Because the diagnostic and therapeutic possibilities in neurological diseases could be improved as a result?
Yes – on the one hand, it is, of course about the bigger questions: how do we think? What's our consciousness? On the other hand, from a clinical perspective neurological diseases are nowhere near as well understood as either cancer or cardiovascular diseases. Considering current global demographic developments, progress in this area is needed because neurodegeneration constitutes one of the principal challenges faced by ageing people.
While a large research facility is unique on the one hand, the number of similar types of facility is on the increase worldwide. What is the relationship between them – is there a lot of competition?
Naturally, we're all competing against each other but it's a healthy competition. There aren't that many facilities. No single facility can afford to develop everything alone, meaning that facility development remains extremely cooperative. Every facility is part of a global evolution. We're constantly in contact with the other facilities – that's the beauty of it – and we learn from each other. The people involved here are excited that the technology is developing everywhere.
You were born in Switzerland but have spent your entire life in the US and Great Britain?
That's correct – but I've had strong ties with Switzerland for my whole life. At home, we only spoke Swiss German. And as a child, I spent several summers at my grandparents' house in Switzerland. I've often been to Europe and especially Switzerland for work, too. But Switzerland is a bit different, of course…
“Different” in what respect?
In a way, Switzerland is more international than Europe's big countries. Great Britain, France and Germany are quite self-contained. Switzerland can't afford this. In terms of population, the country is approximately the size of London; in other words, the same size as a major European metropolitan area. In China, it would be a medium-sized city. Without an international dimension, Switzerland wouldn't be competitive due to its small size.
Interview: Martina Gröschl