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Mitigating Background Caused by Extraneous Scattering in Small-Angle Neutron Scattering Instrument Design

Published

Author(s)

John Barker, Jeremy C. Cook, Jean Philippe Chabot, Steven R. Kline, Zhenhuan Zhang, Cedric V. Gagnon

Abstract

Measurements, calculations and design ideas to mitigate background caused by backscattering in small-angle neutron scattering (SANS) instruments are presented. Backscattering includes all processes such as incoherent, inelastic, and Bragg diffraction that backscatter neutrons out of a surface. Three primary sources of this type of background are investigated: the beamstop located in front of the detector, the inside lining of the detector vessel and the environment surrounding the sample. SANS measurements were made where materials with different albedo were placed in all three locations. Additional measurements of the angle dependent backscattering over the angle range of 0.7π rad to 0.95π rad were completed on 16 different materials at five wavelengths. The data were extrapolated to cover scattering angles from π/2 to π rad to estimate the materials' albedo. Modifications to existing SANS instruments and sample environments to mitigate the backscattered background are discussed.
Citation
Journal of Applied Crystallography
Volume
54
Issue
2

Keywords

Albedo, Backscattering, SANS, neutron, background, shielding, beamstop

Citation

Barker, J. , Cook, J. , Chabot, J. , Kline, S. , Zhang, Z. and Gagnon, C. (2021), Mitigating Background Caused by Extraneous Scattering in Small-Angle Neutron Scattering Instrument Design, Journal of Applied Crystallography (Accessed October 19, 2021)
Created March 31, 2021, Updated September 16, 2021