New high-flux small-angle neutron scattering instrumentation and the Center for Structural and Molecular Biology at Oak Ridge National Laboratory

A number of upgrades are currently being undertaken at the High Flux Isotope Reactor (HFIR), including the installation of a supercritical hydrogen moderator (T ~ 20 K) that will be one of the "brightest" cold sources currently available. It will feed four cold neutron guides (CG1-4), each with new instrumentation. CG2 and CG3 are reserved for two new small-angle neutron scattering (SANS) instruments. A 40 m SANS instrument (SANS1), funded by the Department of Energy (DOE) Office of Basic Energy Sciences and the University of Tennessee, Knoxville is designed for CG2. Our 35 m small-angle neutron scattering facility (SANS2 on CG3) is optimized for the study of biological systems as part of a Center for Structural and Molecular Biology (CSMB), funded by the DOE Office of Biological and Environmental Research. In addition to the new SANS facilities, there will be suite of instruments including a reflectometer and a cold triple-axis spectrometer. Both SANS facilities will have variable wavelength and large area (1m²) high count-rate detectors that can translate 45 cm off axis to increase the dynamic Q-range (< 0.001-1 Å^-1 overall). As the HFIR is one of only two reactors with a core flux > 10¹⁵ neutrons/s/cm², the beam intensities (up to 10⁷/s/cm²) will be comparable to the best facilities worldwide and this will enhance our ability to collect data from synthetic and biological macromolecules more quickly and study smaller sample quantities.