A thermal Triple-Axis Spectrometer (TAS) is in a suite of eight instruments to be built around the new “Replacement Research Reactor” (OPAL) at the “Australian Nuclear Science and Technology Organisation” (ANSTO, Sydney). This TAS will be based at the reactor face. Its main features will be presented: compact shielding, variable incident neutron energy, double focusing monochromator and analyser, polarisation-analysis mode. Triple-Axis Spectrometery is a key technique for the measurement of excitations in materials – collective excitations (phonons and magnons), diffusive excitations like spin fluctuations and localised excitations arising from the hopping of charge in materials, crystal-field levels and some intramolecular modes. It is likely that it will become important in soft matter studies in the future. Some examples will be presented.
Bragg Institute, Australian Nuclear Science and Technology Organisation, ANSTO