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NG7 SANS - Small Angle Neutron Scattering


Perspective view of NG7 SANS instrument at NCNR

The 30 meter long Small-Angle Neutron Scattering (SANS) instrument on neutron guide NG7 was the first new instrument to go into operation in the NCNR guide hall in May 1991. Jointly developed and sponsored by the NCNR, the ExxonMobil Research and Engineering Co., and the University of Minnesota, the instrument has undergone a number of improvements over the years to remain, along with its near-twin on guide NGB, the best such instruments in the U.S. The improvements, including a higher resolution 2D detector, and focusing refractive lenses have extended the Q-range of the instrument from 0.01 nm-1 to 7.0 nm-1 to elucidate structural features in materials ranging from roughly 1 nm to over 500 nm to be probed. A polarizing guide and RF flipper were installed in 2014. Fully polarized beam measurements are possible with the use of a 3He analyzer.


NG7 SANS flux at the sample


Q-Range 0.01 nm-1 to 7.0 nm-1
Size Regime ~1 nm to ~500 nm
Source Neutron Guide (NG-7), cross-section: 50 mm x 50 mm
Monochromator Mechanical velocity selector with variable speed and pitch
Wavelength Range 4.5 Å to 20.0 Å
Wavelength Resolution 11% to 30% Δλ/λ (FWHM)
Source-to-Sample Distance 4 m to 16 m in 1.5m steps via insertion of guide sections
Collimation Circular pinhole collimation or focusing biconcave lenses
Sample Size 5 mm to 25 mm diameter
Sample-to-Detector Distance 1.0 m to 15.3 m continuously variable
Detector 640 mm x 640 mm 3He position-sensitive proportional counter with a 5.08 mm x 5.08 mm resolution
Optional Capabilities
  • Focusing biconcave lenses
  • Polarizing guide and RF flipper

Scientific Opportunities/Applications

How NG7 SANS Beam Time is Typically Allocated in Each 38 Day Cycle:

  • 3 days - ExxonMobil Co.
  • 3 days - University of Minnesota
  • 10 days minimum - BTAC Proposals
  • Balance (22 days or less) - Proprietary and Collaborative Research
Created October 1, 2018, Updated January 14, 2020