This activity supports the operation of three DOE neutron scattering facilities, which are unique and effective tools for probing the structure of matter. Neutron scattering is particularly well-suited for determining the atomic positions of both light and heavy atoms in a solid and thermal fluctuations in these positions. In addition the neutron scatters from magnetic moments in the material thus providing information on the magnetic structure as well. The neutron energy is well-matched to that of elementary atomic and magnetic excitations (spin waves and phonons) in a material and, via inelastic scattering, can provide data crucial for understanding basic phenomena in superconductors, magnetic systems, and multi-ferroic materials.
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is a 1 MW next-generation short-pulse spallation neutron source for neutron scattering that is among the world’s highest intensity neutron sources The SNS consists of a linear accelerator coupled to a pulse compressor ring that delivers short (microsecond) proton pulses to a target/moderator system where neutrons are produced by a process called spallation. The neutrons so produced are then used for neutron scattering experiments. Specially designed scientific instruments use these pulsed neutron beams for a wide variety of investigations. There is currently one target station that can accommodate 24 instruments, and the potential exists for adding a second target station later and additional instruments.
The High Flux Isotope Reactor(HFIR) at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that began full-power operations in 1966 at the design power level of 100 megawatts. Currently, HFIR operates at 85 megawatts to provide state-of-the-art facilities for neutron scattering, materials irradiation, and neutron activation analysis and is the world's leading source of elements heavier than plutonium for research, medicine, and industrial applications. The neutron-scattering instruments installed on the four horizontal beam tubes are used in fundamental studies of materials of interest to solid-state physicists, chemists, biologists, polymer scientists, metallurgists, and colloid scientists. Recently, a number of improvements at HFIR have increased its neutron scattering capabilities to 14 state-of-the-art neutron scattering instruments. These upgrades include the installation of larger beam tubes and shutters, a high-performance liquid hydrogen cold source, and a cold-neutron guide system. The new installation of the cold source provides beams of cold neutrons for scattering research that are as bright as any in the world. Use of these forefront instruments by researchers from universities, industries, and government laboratories are granted on the basis of scientific merit.
The Lujan Neutron Scattering Center (Lujan Center) at Los Alamos National Laboratoryis an intense pulsed neutrons source serving a variety of instruments for neutron scattering studies. The Lujan Center features instruments for measurement of the local atomic and magnetic structure of materials, high-pressure and high-temperature diffraction, strain and texture measurement, and polarized and unpolarized beam relectometers for study of magnetic, polymer and biological systems. In addition a single crystal machine is available for protein structure studies. The facility has a long history and extensive experience in handling actinide samples. The Lujan Center is part of the Los Alamos Neutron Science Center (LANSCE), which is comprised of a 800-MeV proton linear accelerator, a proton storage ring, and neutron production targets delivering neutrons to the Lujan Center and the Weapons Neutron Research facility for national security and civilian research.
Dr. James J. Rhyne and Dr. Peter L. Lee