Mission Statement

A collaboration of the Neutron Sciences Directorate at Oak Ridge National Laboratory and the University of Tokyo, as part of the US-Japan Cooperative Program on Neutron Scattering, the Cold Neutron Triple-Axis Spectrometer (CTAX) will enable better analysis of low-energy excitations in materials, which is useful for studying magnetic effects. More information about how magnetism affects various materials will lead to advancements in storage media, energy, and transportation, as well as many other fields.

Instrument Description

The CG-4C CTAX instrument is a conventional triple-axis spectrometer with variable incident energy and sample-analyzer distances. The Cold Guide 4 bender and guide hall shielding reduce background levels at CG-4C, and the 15-cm-tall guide profile is well exploited by CG-4C′s vertically focusing monochromator (PG 002). To enhance accommodation of strong magnetic fields at the sample position and simplify future polarization analysis, the amount of ferromagnetic material has been minimized in the construction of this instrument.


  • High-resolution measurements of low-energy, atomic-scale dynamics of crystalline solids with high signal-to-noise ratios due to the low background.
  • Studies of magnetic phenomena exploiting the energy range that matches achievable applied fields


Incident energy range:2 - 20 meV
Final energy range:≥3.0meV
Sample scattering angles:-15° ≤ 2Θs ≤ 115°, with additional restrictions depending on Ei
Collimation before mono-chromator:Guide dependent (40′ at 2 meV, 20′ at 20 meV)
Collimation after mono-chromator:10′, 20′, 40′, 80′