Neutron triple-axis spectrometry

Triple-axis spectrometry (TAS, T also resolved as "three", S also resolved as "spectroscopy") is a technique used in inelastic neutron scattering. The instrument is referred to as triple-axis spectrometer (also called TAS). It allows measurement of the scattering function at any point in energy and momentum space physically accessible by the spectrometer.

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History

The triple-axis spectrometry method was first developed by Bertram Brockhouse at the NRX research reactor at the Chalk River Laboratories in Canada. The first results from the prototype triple-axis spectrometer were published in January 1955 and the first true triple-axis spectrometer was built in 1956. Bertram Brockhouse shared the 1994 Nobel prize for Physics for this development, which allowed elementary excitations, such as phonons and magnons, to be observed directly. The Nobel citation was "for pioneering contributions to the development of neutron scattering techniques for studies of condensed matter" and "for the development of neutron spectroscopy".

TAS Instruments in current use

FRM-II Forschungsneutronenquelle Heinz Maier-Leibnitz

• PANDA - a cold neutron triple-axis spectrometer.

• PUMA - a thermal neutron triple-axis spectrometer with multianalyser-detector option.

Institut Laue-Langevin

• IN1 - a hot neutron triple-axis spectrometer.

• IN3 - a thermal neutron triple-axis spectrometer for tests.

• IN8 - a high-flux thermal neutron triple-axis spectrometer.

• IN12 - a cold neutron triple-axis spectrometer.

• IN14 - a cold neutron triple-axis spectrometer with polarized neutron capability.

• IN20 - a thermal neutron triple-axis spectrometer with polarized neutron capability.

• IN22 - a thermal neutron triple-axis spectrometer with polarized neutron capability.

• D10 - a thermal neutron four-circle diffractometer with a triple-axis energy analysis option.

CEA/Saclay Laboratoire Léon Brillouin

• 1T-1 - a double-focusing thermal neutron triple-axis spectrometer.

• 2T-1 - a thermal neutron triple-axis spectrometer.

• 4F-1 - a cold neutron triple-axis spectrometer.

• 4F-2 - a cold neutron triple-axis spectrometer.

NIST Center for Neutron Research

• SPINS - a cold neutron triple-axis spectrometer with polarized neutron capability.

• BT-7 - a thermal neutron triple-axis spectrometer with polarized neutron capability.

• BT-9 - a thermal neutron triple-axis spectrometer.