The Triple-Axis Spectrometers at the High Flux Isotope Reactor

Abstract

Since the development of the first triple-axis spectrometer by Brockhouse in the 1950s, this type of instrument has remained the most versatile tool to study the elementary excitations of solids, such as phonons and magnons. This versatility arises from the ability to measure the scattering function at any point in momentum-energy space physically accessible by the spectrometer. Currently there are three thermal triple axis spectrometers at the High Flux Isotope Reactor (HFIR) with complementary capabilities. A cold neutron triple axis spectrometer will be installed at the new HFIR cold neutron guide hall within the next year. The high flux and a wide range of incident energies (between 5 and 120 meV) makes these instruments particularly well-suited for the study of current problems in condensed matter physics like that of magnetic excitations in high-Tc superconductors, multiferroic, colossal magnetoresistance manganites, heavy fermions, “bad” metals, quantum magnets, magnetic multilayers, and commercial magnetic alloys.