The Emu backscattering spectrometer, located at the OPAL reactor at ANSTO, is a state-of-the-art instrument for high-resolution neutron spectroscopy. It enables the investigation of molecular relaxation phenomena with correlation times ranging from tens of picoseconds to nanoseconds. With an energy resolution of 1 µeV (FWHM) and an energy transfer range of ±31 µeV, Emu is particularly well suited for quasi-elastic neutron scattering (QENS) studies of organic and hydrogen-rich materials.
The spectrometer employs Si (111) crystals in a backscattering configuration, providing a Q-range of 0.2–1.95 Å⁻¹. A temperature range from 50 mK to 800 K, together with ancillary equipment such as controlled gas environments, applied electrical fields and pressure cells, enables experiments under a wide variety of conditions. Merit-based access supports an international user community spanning soft-matter physics, materials science, chemistry, and biophysics.
Over nearly ten years of operation, Emu has produced substantial scientific output, consistently generating high-impact publications across diverse research areas. Highlights include studies of polymers, membranes, proteins, nanocomposites, and slow water dynamics. Selected examples will be presented to illustrate the instrument’s scientific capabilities.
By combining advanced performance with ongoing technical developments, Emu continues to play a key role in enabling detailed investigations of molecular dynamics on nanometre length scales and nanosecond time scales, contributing to advances in materials research.