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The 6,000-strong international community of users of neutron scattering techniques needs to take a longer-term view of future needs for large machines, and be better organized in mustering political support, if it is to enjoy an adequate supply of neutrons early in the next century.

This is a key message of a report produced by the Megascience Forum of the Organization for Economic Cooperation and Development (OECD). It predicts that the world supply of neutron sources will fall far short of future demand early next century unless decisions to build new ones are taken within the next five yearsFootnote 1.

There are now around 26 major neutron sources in the OECD countries and Russia. But most will reach the end of their lifetimes between 2005 and 2015, and the report warns that, unless prompt action is taken, the capacity of neutron sources in 2010-20 will be one-third of that available today.

Andrew Taylor, director of the ISIS neutron facility in the United Kingdom, endorses the report's comment that, whereas particle physicists plan ahead for the large facilities on which they depend, neutron users have been less well organized.

The problem, says Taylor, is that neutron sources are not big machines used by a few, but a shared tool used by researchers from many disciplines, often for short periods. “It has been difficult to get young scientists interested in something that is not going to exist for twenty years,” he says.

The report warns that a neutron drought would be a “serious threat” to scientists working in many disciplines, including biology, Earth sciences, engineering and materials science. At present, about 4,000 researchers in Europe use neutron scattering techniques, with another 1,000 in the United States and 1,000 in Japan.

The greater activity in Europe reflects the presence of the world's two most powerful neutron sources, the Institut Laue-Langevin (ILL) in France and ISIS. The United States, which was at the forefront of neutron scattering in the 1960s, has since fallen behind.

But the report points out that the planned US$1.3 billion national Spallation Neutron Source at Oak Ridge, Tennessee, will allow the United States to catch up with Europe. The project was approved in the US budget last month (see Nature 395, 531; 1998 ). Japan has plans for similar facilities.

Europe is pressing ahead with plans for a new five-megawatt European Spallation Source, now in the research and development phase. Its proponents hope to complete this by 2003, and to get political backing by 2005 for the machine to come on-line by 2016.

The report encourages neutron users to cooperate in putting together detailed plans for new machines and attracting political support, and says that greater attention needs to be paid to financing adequate instrumentation.

It points out that the ILL reactor provides neutrons to 43 instruments, used by about 1,200 scientists a year from disciplines such as biology chemistry and solid-state physics, whereas the similarly sized source High-Flux Isotope Reactor at Oak Ridge, has only 11 instruments. “New sources attract bright young people and lead to development of new instruments,” adds Taylor.