Feature, 21 January 2011

“Good science always finds applications.”

Chairman of the Management Board Massimo Altarelli speaks about his job, the facility, politics, and international science. This interview was produced for the German physics portal Welt der Physik. In the German version of this article, you can find a short video of the interview as well.

Mr Altarelli, you have been working in solid-state physics for years, and now you are head of a research company with limited liability. What is more complicated: the laws of electrodynamics or German company law?

German company law is dreadful, but you have to face the realities of life. In large research institutions, which cost a lot of money, you are necessarily operating in a legal context. For me, this is a service to the scientific community. It is only reasonable that older people like myself do this. It would be absurd to ask 25-year-old PhD students to take charge of these things.

Do you sometimes wish you were back at the researcher’s desk?

I am trying to build a research instrument, which of course has legal and management aspects, but I am still sitting at the researcher’s desk. I read the scientific literature and in a small fraction of my time, I also write some. I don’t feel so drastically cut off from the word of research as people might think. I still feel like a scientist.

You come from theoretical physics. Now you are director of an experimental research organization. Does this require a different way of thinking?

I studied theoretical physics and I still am a theorist. But I have had close connections with experimental institutions for a long time. So this is nothing new to me.

In 1983 already, when I was 35 years old, I served as temporary head of an experimental research institute in Grenoble. After that, I was research director at the ESRF, the European Synchrotron Radiation Facility, for seven years.

What kind of research will be carried out at the European XFEL?

Free-electron lasers are the latest generation of accelerator-based light sources. We will carry out photon science. Two things will be especially new and interesting. On one hand, our facility will provide very short and brilliant light pulses. It will generate flashes lasting only 10 femtoseconds (10^-14s). These enable researchers to follow physical processes on the same short time scale – much like in a movie. The second interesting aspect is: the European XFEL is a laser in the sense that you have a coherent source with which you can take holographic, that is three-dimensional, images.

This brings us to possible applications, such as studies of the structure and dynamics of molecules without the need to crystalize them first. Materials scientists, chemists and biologists will be able to observe processes in real time and gather information about individual nanostructures or even single molecules. This is very exciting.

And to generate these flashes, you need an approximately three-kilometre-long facility?

Until recently, accelerator-based light sources were circular, for instance synchrotrons such as PETRA III or DORIS at DESY. It was shown, however, that using this ring geometry, you cannot become much better than PETRA III currently is. To achieve a quantum leap in this area, that means to generate fully coherent X-ray radiation in ultra-short pulses, you must switch to a geometry in which the electrons radiate only once. In a ring, they circulate and radiate and radiate and radiate – hundred thousands or millions of times per second. This is not compatible with the electron beam quality required for ultra-short and coherent X-ray flashes. Thus you have to build a linear machine.

For a linear machine, the rule is: the higher the electron energy you want to reach, the longer the facility has to be. The electron accelerator must therefore be long enough to give the electrons an energy of several billion electronvolts.

To generate coherent light, you also need long undulators – periodic arrays of magnets in which the accelerated electrons radiate the X-ray flashes. In the end, the beam is also very colliminated. You thus have to give it a bit of drift space in order to achieve a beam diameter of around half a millimetre at the experiment. And so the whole thing adds up to three kilometres – because of these various necessities.

So the quality requirements for the electron beam are very high?

Yes, this is the reason why our accelerator is superconducting. This is a big advantage over our competitors. The other facility, the LCLS in Stanford, which is already in operation, is based on an old accelerator working at normal temperature. Such a facility is also being constructed in Japan. With an accelerator operating at normal temperature, however, you can only generate 100 or 200 pulses per second. At the European XFEL, we want to produce 27 000 pulses per second and maybe even more. This is a difference of two orders of magnitude in the performance of the machine. And this difference comes from the superconducting technology, which was developed mostly at DESY.

Two orders of magnitude – what does this mean in concrete terms?

For an experiment in which you want to study the structure of a single molecule, you have to make two very small objects collide: an ultra-short light pulse and a molecule. This is very improbable and you have to try it with many pulses before you score a hit. It is a decisive advantage then to have 27 000 pulses per second instead of 200. This is true for all diluted samples.

If you could submit a proposal for beam time at the European XFEL today, what would you like to study?

The idea to study the structure of individual molecules is very ambitious, and maybe we will have to carry out experiments for a few years before we really reach this point. But one could begin by investigating individual nanostructures.

Or the formation of new phases. We know that a liquid cooled down to its freezing point becomes solid. Water turns to ice. By chance, there is sometimes a larger nucleation point at which this happens, and the thing grows. We have a theoretical understanding of this process, and we have been able to observe it in computer simulations. No one has ever observed such processes directly, however. This would be extremely interesting: how these nucleation points are created accidentally and disappear again, or how they stabilize and grow until the whole system changes into a new phase.

Does this satisfy the curiosity of the scientists only or are there any applications?

Of course there are applications. People always emphasize the difference between pure and applied science. I think it is more important to differentiate between good and bad science. Good science always finds applications. It is just difficult to say if this will happen in one year, in five years, in 15 years or even later. There is nothing that is really completely useless if it is scientifically sound and well founded.

For example: the purest and most abstract realm of mathematics is number theory. Since the 17th century, people have been studying the properties of prime numbers. This may be interesting, a kind of Sudoku game for mathematicians, but does it make sense? Yes! Two hundred years later, computers were devised which make use of this mathematics. The fact that your credit card account will not be plundered by a hacker tomorrow if you pay with it today on the Internet, is owed to theorems of number theory that were discovered in the 18th century.

And then all our solid-state technology – semiconductors, integrated circuits! It is based on discoveries made in the 1940s and 1950s in solid-state physics. At first, people had very few ideas what it could be good for, but meanwhile one could say that it is a basis of out civilization.

If the science is good, it finds an application.

To be less philosophical: when I talk about decoding the structure of individual molecules, this could lead to new applications in the pharmaceutical industry. I cannot say that it could be used to heal cancer, but we also cannot exclude it.

But one has to be patient.

You are a full-blooded scientist. Were there ever any alternatives for you?

I chose physics as my discipline relatively early, but for some time I also considered becoming a doctor. But there is a lot of chance involved in such choices. I have an older brother who is a particle physicist. This is how physics came into the family.

The research at the European XFEL will bring medical aspects into your life.

Yes, this is true. There will be medical applications. But I wanted to become a doctor to have the close contact with the patient.

You have been in the USA, in Italy, in France, and you have carried out research in Germany for a long time. Are there national ways to do science?

The research itself is the same everywhere. The laws of nature do not change from France to the USA. What does change is the way research is organized. In the past, there were rich persons like Lord Kelvin who had a private laboratory in his cellar. Today, however, research is a highly structured and highly organized activity. This structuring and organization of the research institutions is different in all countries, because the culture and the institutions are different. In the US there is the phenomenon of the private university. Harvard and Princeton are beacons of science. This is something that does not exist in Germany.

But regardless of where a young scientist is brooding over a problem, in Harvard, in a Max Planck Institute or in an institute in Japan – he does the same work.

Politically the European XFEL was to be a European project right from the start. It did not become a project of the EU, however. Germany holds over 50%, Russia joined in later with 25%. How much Europe is in the European XFEL?

First of all: Germany and Russia are part of Europe, as far as I know. But I agree that the other European countries should have contributed more. Our staff is very international, however, and we will do our best to ensure that this will remain so. Our surroundings too are truly European. We don’t want to have only scientists from Hamburg-Lurup or Hamburg, but the best scientists from all of Europe.

I believe that the European Community should participate more in such international research institutions as the European XFEL, which are very important for the European research strategy. However, the EC helped us with a small, albeit very timely injection of funds to reach a critical mass.

The whole thing is sometimes politically tricky. The international negotiations were dragging on. Were you surprised about how difficult this was to be?

Not really. I followed the birth of the European Synchrotron Radiation Facility in Grenoble. It was not very different. With one distinction: the world today is in a very difficult economical and financial situation.

But the perennial discussions about individual words and where the commas have to be set in the agreements, this is something I had already witnessed. It seems to be an unavoidable aspect of international cooperation.

On the other hand: in international institutions, you have to fix a lot in the beginning, but afterwards they are very stable. Once they got moving, they have no problems to come from each year to the next. National institutions in contrast are much weaker. Here, national political and financial disruptions can have a much higher impact.

The DESY research centre is the main shareholder. How is the cooperation between the two institutes?

Excellent. WE have been more or less adopted by DESY. We started as a project at DESY, we were employed by DESY, paid by DESY, thanks to DESY we had access to lots of scientific services and infrastructure.

Now we are starting to become a bit more independent, though DESY is still very closely involved in the project. DESY will conduct and coordinate the construction of the accelerator. This is a huge job. DESY is also still our host laboratory. We are using many DESY services and infrastructures in our daily work.

When the facility will be completed, you will have reached the age of retirement. Is this comforting or disappointing?

It is not especially comforting to get older, it is irritating. But life goes and we go too. When the European XFEL will be completed, I will be 67 or 68. Maybe people will say: now is time for quietness, and I will go into retirement. Or maybe I can still do something. One thing is sure: my interest in science will not be switched off. I will have more time for research. There is no law that retirees are not allowed to think and write. I am not very worried about this.

Thank you very much for your time.

Interview: Dirk Rathje // Translation: Ilka Flegel