Three-Axis Spectrometer group (TAS)
The instruments of the Three-Axis Spectrometer group of the Institut Laue-Langevin are dedicated to measuring the dynamics of microscopic matter waves in arrays of atoms in single crystals and the analogous excitations of magnetic spins in exotic materials.
The Three-Axis Spectrometer (TAS) was invented en 1952 by the Nobel prize winner B.N. Brockhouse. It uses an analyser crystal to measure the energy of neutrons scattered from the sample. This then can detect that the neutron wavelength (energy) has changed during the scattering process, in contrast to a diffractometer which measures all neutrons scattered by the sample with no distinction.