Triple-axis spectrometry (TAS, T also resolved as "three", S also resolved as "

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...

") 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 Scattering is a term used in physics to describe a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including ...

function at any point in energy and

momentum In Newtonian mechanics, momentum (more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. If is an object's mass an ...

space physically accessible by the spectrometer.

History

{{expand section, date=February 2019 The triple-axis spectrometry method was first developed by

Bertram Brockhouse Bertram Neville Brockhouse, (July 15, 1918 – October 13, 2003) was a Canadian physicist. He was awarded the Nobel Prize in Physics (1994, shared with Clifford Shull) "for pioneering contributions to the development of neutron scatterin ...

at the National Research Experimental

NRX NRX (National Research Experimental) was a heavy-water-moderated, light-water-cooled, nuclear research reactor at the Canadian Chalk River Laboratories, which came into operation in 1947 at a design power rating of 10 MW (thermal), increasing to ...

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.

shared the 1994 Nobel prize for Physics for this development, which allowed elementary excitations, such as

phonon In physics, a phonon is a collective excitation in a periodic, Elasticity (physics), elastic arrangement of atoms or molecules in condensed matter physics, condensed matter, specifically in solids and some liquids. A type of quasiparticle, a phon ...

s 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 The Research Neutron Source Heinz Maier-Leibnitz (Forschungsreaktor München II or FRM II) (german: Forschungs-Neutronenquelle Heinz Maier-Leibnitz) is a leading German research reactor and neutron source, named in honor of the physicist Heinz Ma ...
Forschungsneutronenquelle Heinz Maier-Leibnitz

*PANDA - a

cold neutron The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are Neutron moderator, moderate ...

triple-axis spectrometer. *PUMA - a thermal neutron triple-axis spectrometer with multianalyser-detector option. *TRISP - a thermal neutron triple-axis spin echo spectrometer. *KOMPASS - a cold triple-axis spectrometer with polarization analysis *MIRA - a cold triple-axis spectrometer

Helmholtz-Zentrum Berlin für Materialien und Energie Helmholtz-Zentrum Berlin für Materialien und Energie (Helmholtz Centre for Materials and Energy, HZB) is part of the Helmholtz Association of German Research Centres. The institute studies the structure and dynamics of materials and investigate ...

FLEX
- a cold neutron triple-axis spectrometer with optional Neutron Resonance Spin Echo mode.
E1
- a thermal neutron triple-axis spectrometer with Polarization Analysis.

Paul Scherrer Institut

RITA-II
- a cold-neutron triple-axis spectrometer.
TASP
- a cold-neutron triple-axis spectrometer with polarization analysis and neutron spherical polarimetry.
EIGER
- a thermal-neutron triple-axis spectrometer.

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 Polarization or polarisation may refer to: Mathematics *Polarization of an Abelian variety, in the mathematics of complex manifolds *Polarization of an algebraic form, a technique for expressing a homogeneous polynomial in a simpler fashion by ...

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

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

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 The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
Center for Neutron Research

SPINS
- a cold-neutron triple-axis spectrometer with

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

capability.
MACS
- a high-flux cold-neutron multi-axis spectrometer.

ORNL Oak Ridge National Laboratory (ORNL) is a U.S. multiprogram science and technology national laboratory sponsored by the U.S. Department of Energy (DOE) and administered, managed, and operated by UT–Battelle as a federally funded research and ...

HFIR The High Flux Isotope Reactor (HFIR) is a nuclear research reactor at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, United States. Operating at 85 MW, HFIR is one of the highest flux reactor-based sources of neutrons for condense ...

CTAX
- a cold-neutron triple-axis spectrometer.
PTAX(HB1)
- a thermal-neutron triple-axis spectrometer specifically designed for

measurements.
FIETAX (HB1A)
- a fixed incident energy thermal-neutron triple-axis spectrometer.
TAX (HB3)
- a high-flux thermal-neutron triple-axis spectrometer.

ANSTO Bragg Institute

TAIPAN
- a thermal-neutron triple-axis spectrometer with

capability an
beryllium-filter option

SIKA
- a cold-neutron triple-axis spectrometer with

capability.

MURR
University of Missouri Research Reactor

Triax
- a thermal-neutron triple-axis spectrometer.

External links

Nobelprize.org page for the 1994 Nobel Prize for Physics
Neutron-related techniques