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BT5 USANS - Ultra Small Angle Neutron Scattering

BT5 USANS Instrument Schematic

A perfect crystal diffractometer (PCD) for ultra-high resolution small-angle neutron scattering (USANS) measurements has been in operation at the thermal neutron beam port, BT-5 since 2002. The PCD increases the maximum size of features accessible with the NCNR's 30-m long, pinhole collimation SANS instruments by nearly two orders of magnitude, from ~102nm to 104 nm.


USANS geometry diagram
Neutron ray diagram for the BT5 USANS instrument.


Q-range 0.0003 nm-1 to ~0.1 nm-1
Size Regime 0.1 μm to 20 μm
Source Beam Tube (BT-5)
Monochromator Pyrolytic Graphite Premonochromator Followed by a Triple-Bounce Si(220) Monochromator
Wavelength 2.4 Å and 6% Δλ/λ
Flux at Sample <17,000 neutrons-cm-2-s-1
Sample Size Up to 5 cm high x 5 cm wide x 10 mm thick
Analyzer Triple-Bounce Si(220)

Scientific Opportunities/Applications

How BT5 USANS Beam Time is Typically Allocated in Each 38 Day Cycle:

  • 22 Days - BTAC Proposals
  • 16 Days - Proprietary and Collaborative Research
Created September 13, 2018, Updated May 15, 2023