Instrument Description

CORELLI is a statistical chopper spectrometer with energy discrimination. It's designed and optimized to probe complex disorder in crystalline materials through diffuse scattering of single-crystal samples. The momentum transfer ranges from 0.5 to 12 Å-1, and the energy of incident neutrons ranges from 10 to 200 meV.

This instrument combines the high efficiency of white-beam Laue diffraction with energy discrimination by modulating the beam with a statistical chopper. A cross-correlation method is used to reconstruct the elastic signal from the modulated data. Accurate modeling of the short-range order associated with the diffuse scattering requires measurements over large volumes of three-dimensional reciprocal space, with sufficient momentum resolution to distinguish the diffuse signal from the strong Bragg peaks.

Applications

  • Material science, including colossal magnetoresistance materials, ferroelectric relaxors, and fast ion conductors
  • Condensed matter physics, including high-temperature superconductors, geometrically frustrated systems, and quantum critical phenomena
  • Molecular systems, including molecular solids and microporous framework systems

Specifications

ModeratorAmbient H2O decoupled poisoned
Source- to-sample distance20 m
Sample- to-detector distance2.5 m
Anular coverage-21.9 to +148.2° horizontally ±28.5°vertically
Energy resolutionΔE/Einc~ 8% (FWHM) at Einc=100 meV
Momentum resolutionΔQ/Q ≤ 7x10-3at 90oat Q=10 Å-1
Incident energy range10–200 meV
Momentum transfer1 - 12 Å-1
Beam size at sample position~1cm2
Minimum solid angle coverage0.8 sr

Sample Environment

  • Low background close cycle refrigerator (CCR), with option of high temperature sample stick (6K < T < 750 K)
  • Orange cryostat (1.6 K < T < 300 K)
  • 3Helium insert (300 mK < T < 300 K)
  • Pressure cell ( P < 1.8 GPa)
  • Magnetic field ( H < 5 Tesla)
  • Pulsed magnetic field (H < 30 Tesla, please contact instrument scientist for details)