Page 224 - Neutrons for Sciences and Society

Neutrons for Science
full design power of 1 MW in 2015.] These machines are designed to produce peak fluxes of 1017 neutrons per centimetre squared per second. The solution that comes to mind is to plan now to replace the ILL reactor by a neutron source more modern and more powerful. The nature of this source is known: a spallation source as in the USA and Japan, which produce neutrons by the impact
of high energy protons on a heavy metal target. There is even a pre-project for a European Spallation Source (ESS). The project is estimated to cost €1500 M.
Like the SNS it will offer pulses of neutrons about 100 times as intense (at the peak of the pulse) as the flux from the reactor of
the ILL. To make optimal use of this intensity requires use of
time of flight techniques. In 2003 the project seemed buried by
the withdrawal from the project of Germany and Great Britain. A letter appeared in Nature in July 2004 which offers new hope127.
It is clear that the choice of potential site for this machine will not be made without difficulty. The arguments already put forward by Fender for the implementation of the ESRF on the site of the ILL seem to apply also to the ESS. This would also assure a long term future for the ILL which has shown its capabilities and deserves to last beyond the lifetime of the current reactor. [2018 addition: This hope has materialized but not for Grenoble since ESS is being built at Lund in Sweden128 for a cost of €1843 M based on 2013 estimations. Its first neutrons are expected in the early 2020s.]
127 Schiermeier, Q., Nature 430, 493 (2004). DOI 10.1038/430493b 128 ESS website: https://europeanspallationsource.se
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