RITA: The reinvented triple axis spectrometer

Abstract

Since the pioneering work of Brockhouse on inelastic neutron scattering the triple-axis spectrometer has been the instrument of choice for studies of dynamics, both magnetic and structural, in single crystals. In the years since the late fifties improvements in source brightness, beam optics, and detector technology have resulted in increased sensitivity and capabilities of the basic triple-axis design. Work has begun at Risø National Laboratory on a new spectrometer design, RITA, the reinvented triple axis, which attempts to incorporate more recent innovations such as multilayer supermirrors and microstrip proportional counters into a rethinking of the triple-axis spectrometer. By optimizing the beam optics using supermirrors and extending the analyser to map regions of (Q, ω) space using an array of independently controllable pyrolytic graphite crystals focussed on an area detector, we hope to increase the efficiency of single-crystal inelastic experiments by about a factor of 20.