07 August 2015

Today a piece of prime farmland, in six years a scientific facility
worth billions – a gigantic microscope, if you will. After years of
preparation and periods of close calls with disaster, the European
Spallation Source (ESS) is now taking form on the drawing board.
Linköping University Professor Karl-Fredrik Berggren piloted the project past some critical pitfalls.

Berggren, now a professor of Theoretical Physics, grew up in Uppsala and was the first student in his family. But his path to the white cap was a crooked one. When he was taking the step from primary to secondary school, it came to light that he did not know how to multiply by eleven.

“We’d just gotten to the tens table...”

He still managed to get into university and get a PhD in the new subject quantum chemistry. His research has focused around electron structures and quantum transport in nanosystems, and included several stints at Cambridge.

In his four decades at Linköping University, his everyday work has been teaching and advising a steady stream of undergraduate and PhD students. In his more open role as Professor Emeritus, he is going more in-depth into, among other things, quantum chaos – the erratic movements of particles in the quantum world, which can be visualised in beautiful images.

From this point of view, his involvement in the ESS was a sidetrack.

Berggren entered the picture at the beginning of 2003 as a spokesman for ESS-S, the Scandinavian initiative in the competition to become the host of this facility for atomic studies. Behind him was a successful effort on Myfab, a national infrastructure for micro- and nanomanufacture, as well as the establishment of MAX-lab and the National Supercomputer Centre in Sweden.

In the 1990s, the ESS Council - an initiative among leading European neutron research laboratories - had outlined a report on how the neutron source should be designed, with technical solutions, economic calculations, and safety assessments. In 2002, the door was open for interested countries to submit tenders. Among the interested parties were two initiatives from Germany, two from Great Britain, and the ESS Scandinavia (ESS-S) located in Lund.

“Everyone took it for granted that Germany would bring home the prize. The little mouse up north couldn’t be taken seriously,” Berggren says.

But by the following year the major German initiative backed out, followed by others. Now it was time for the mouse to flex its muscles. Three driving forces – Berggren as guest professor and head of the project, neutron researcher Patrik Carlsson, and coordinator Carina Johansson, gathered in Lund to continue their work on the Scandinavian initiative.

“We had to work with a very tight planning budget. Both funding and belief in the project were sagging. No Scandinavian government had bitten, while Hungary and Spain had entered as serious competitors.

So it became a question of bringing the issue to the Government Offices, but none of the research ministers at the time showed any interest, much less the Swedish prime minister, Mr Göran Persson. At the same time, both environmental organisations and agricultural representatives mobilised in protest against the project, which was regarded as involving radiation risks and destruction of valuable cultivated land.

“It was a delicate project, and we were on the way towards bankruptcy. We were ready to pack it in when the Knut and Alice Wallenberg Foundation came in with one year of funding. Without that, it would have been finito.”

Another push that got things moving was a ranking of European infrastructure efforts, where the ESS was considered high priority. Suddenly the project gained credibility in the world of research and among decision makers. In the same turn, in 2006, Sweden got a new research minister in Lars Leijonborg, who had a different agenda than his predecessors. Berggren got an audience, Leijonborg got the minister of finance to open his wallet... and the biggest hurdle was cleared.

“An ESS secretariat was formed in Lund in 2007, the money started rolling in, and I’d done my part. But even today, seven years later, the issue of funding remains. The Nordic countries guaranteed 50%, binding agreements with another 17 countries are still missing but they’ll be signed during 2013. It could be a laborious process, given the current economic situation in Europe,” Berggren says.

Neutrons reveal the innermost structure

Spallation originally means “breakdown” and was used in the beginning in the mining industry: breaking down ore into smaller bits. In a neutron source like ESS, tungsten, for example, is bombarded with high-energy protons. Neutrons are then released, which are conducted to experiment stations where they are pushed into the smallest recesses of an object. They are equivalent to the high-energy photons used in an X-ray machine, or electron beams in an electron microscope.

When the neutrons have passed through the object – without destroying it – they are picked up by detectors that measure the changes in velocity and direction. This data yields detailed information on the innermost structure of the sample.

The big challenge is also to make steps in biotechnology. Here, the neutrons occupy a unique position since, in contrast to X-ray beams, they “see” hydrogen atoms – for example how they function in DNA. This helps researchers understand biological systems at the cellular level.

Previously, helium-3 – a much rarer and more expensive material – was used in the detectors. Now, however, researchers at Linköping University have succeeded in baking in thin coatings of another suitable isotope, boron-10.

Text: Åke Hjelm  2013-05-15

Top picture: Schematisk överblick över det tänkta ESS-laboratoriet. Foto: Henning Larsen Architects.

Other pictures: Karl-Fredrik Berggren. Photo: Göran Billeson.