Neutron Sciences Directorate

The EQ-SANS Diffractometer is designed to study non-crystalline, nano-sized materials in solid, liquid, or gas forms such as polymers, micelles, proteins, and other large biological molecular complexes in solution. It offers high neutron flux, broad dynamic Q-range, and overall wide Q-coverage.

EQSANS is located on beam line 6, viewing the top-downstream, coupled supercritical hydrogen moderator. It has a curved multichannel beam bender to avoid the direct line of sight of the moderator, which cleans out the background from the prompt neutron pulse quite effectively. Three bandwidth choppers on the EQ-SANS define a clean wavelength band 3 - 4.3 Å wide at 60 Hz depending on the detector distance being employed. The instrument can operate at 30 Hz to produce two neutron wavelength bands, which provides a wider dynamic Q-range at a single detector distance setting. At present, the instrument has a 1 × 1 m low-angle detector, which could be expanded to 1 × 1.4 m. The low-angle detector can travel along the beam inside the scattering tank, giving a variable sample to detector distances of 1.3 to 9 m.

The available sample environment is an automated sample changer that can be controlled between 5 and 60°C and can accommodate 15 banjo cells or 10 demountable titanium cells. An extended temperature range of 5°C to 130°C can be achieved with improved precision and ramp rates via Peltier units capable to accommodate 12 banjo cells. A furnace is available that can provide temperatures up to 330 °C. A sample tumbler for studying colloids that settle out of solution, and a relative humidity generator that can interface with a goniometer for performing GI-SANS measurements are also available.