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Sweden snares neutron facility

Lund will play host to European Spallation Source.

Sweden seems set to host the ESS. Credit: ESS Scandinavia

Sweden is claiming victory in a long-running battle to host Europe's next-generation neutron-science facility.

The European Spallation Source (ESS), a €1.4-billion (US$2-billion) neutron facility, will be built in Sweden, according to officials there. The site, near the city of Lund, beat rival locations in Spain and Hungary.

The announcement follows a late-night bargaining session between European research ministers ahead of today's Competitiveness Council meeting in Brussels. In the end, seven nations out of 12 potential backers, including France and Germany, voted for the Lund site, with only one, Portugal, voting for the Spanish location, according to Colin Carlile, the director of ESS Scandinavia, the organization in charge of the Swedish bid. The United Kingdom and Czech Republic abstained, and Italy and Switzerland said they would follow the majority.

The vote was a clear endorsement of the Lund site, according to Carlile. "I feel really very pleased," he says. "It's been so long in coming."

But the other candidate host nations are not willing to concede defeat. Yesterday's vote was simply an "opinion", says Lázló Rosta, the project director for ESS Hungary and a scientist at the Budapest Neutron Center. "There is sort of a Swedish advantage, but there is not a final decision," he says. "My feeling is that there should be very important meetings between all the major players."


Neutrons are an important probe for a wide variety of materials and biological molecules. Unlike X-rays, which scatter off electrons on the surface of atoms, neutrons ricochet off atomic nuclei. That allows them to distinguish between different isotopes of the same element, as well as probe nuclear properties such as magnetism. Early on, researchers used reactors to produce neutrons, but more recently they have accelerated protons onto a heavy metal target. This technique, known as spallation, can create higher-powered neutron beams using less energy than required by a reactor.

There is sort of a Swedish advantage, but there is not a final decision. Lázló Rosta , ESS Hungary

The ESS has been on European neutron scientists' drawing board for the best part of a decade. Germany had originally offered to host the site, but later withdrew after the project received only a mediocre review from the nation's science council (see 'German council confounds plans for neutron project'). Since then, it has been in search of a home, and most recently at the centre of a battle between Sweden, Spain and Hungary. In an unusual move, Spain and Hungary had promised to endorse each other's sites if either was chosen over Sweden.

But Sweden appears to have won. Carlile says that under the terms offered to the research ministers, Sweden, together with its Nordic and Baltic partners, will pay 50% of the project's construction costs. The team is looking for at least 35% of the funding to come from other nations such as the UK, France and Germany. The remainder, up to 15%, will be paid for with a bridging loan from the Swedish government.


Rosta says that he believes there may be a way to include the Hungarian and Spanish proposals in the Swedish bid. The idea, he says, would be to develop the ESS accelerator in Spain and the instrumentation in Hungary. Alternatively, he says, one of the two sites could play host to a smaller spallation neutron source. "We would like to see the three sides arrive at a win-win situation," he says.

Since Europe's protracted site selection process began, both the United States and Japan have completed neutron facilities of their own. But the ESS will be more powerful than the competition, according to Peter Tindemans, chairman of the ESS preparatory phase and an independent consultant based in The Hague. When it is completed, the ESS will deliver a 5-megawatt beam of neutrons to some 22 instruments. That will make it more powerful than the US facility, the current global leader.

Carlile says that he hopes an agreement on cost sharing will come within months, so that construction can begin in 2012. That schedule would see the ESS delivering its first neutrons between 2018 and 2019.


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The European Neutron Portal

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Brumfiel, G. Sweden snares neutron facility. Nature (2009).

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