The National Spallation Neutron Source (NSNS) project

The need and justification for new sources and instrumentation in neutron science have been firmly established by numerous assessments since the early 1970s by the scientific community and the U.S. Department of Energy (DOE). In their 1996 budget, the DOE Office of Energy Research asked ORNL to lead the R&D and conceptual design effort for a next-generation spallation neutron source to be used for neutron scattering. To accomplish this, the NSNS collaboration involving five national laboratories (ANL, BNL, LANL, LBNL, and ORNL) has been formed. The NSNS reference design is for a 1-GeV linac and accumulator ring which delivers 1-MW proton beams in microsecond pulses to a mercury target; neutrons are produced by the spallation reaction, moderated, and guided into an experimental hall for neutron scattering. The design includes the necessary flexibility to upgrade the source in stages to significantly higher powers in the future and to expand the experimental capabilities. This paper describes the origins of NSNS, the current funding status, progress on the technical design, user community input and intended uses, and future prospects.