Abstract
The small-angle neutron scattering instruments at the Oak Ridge National Laboratorys High Flux Isotope Reactor recently upgraded the area detectors from the large, single volume crossed-wire detectors originally installed to staggered arrays of linear position-sensitive detectors (LPSDs). The specific geometry of the LPSD array requires that approaches to data reduction traditionally employed be modified. Here, two methods for correcting the geometric distortion produced by the LPSD array are presented and compared. The first method applies a correction derived from a detector sensitivity measurement performed using the same configuration as the samples are measured. In the second method, a solid angle correction is derived that can be applied to data collected in any instrument configuration during the data reduction process in conjunction with a detector sensitivity measurement collected at a sufficiently long camera length where the geometric distortions are negligible. Both methods produce consistent results and yield a maximum deviation of corrected data from isotropic scattering samples of less than 5% for scattering angles up to a maximum of 35°. The results are broadly applicable to any SANS instrument employing LPSD array detectors, which will be increasingly common as instruments having higher incident flux are constructed at various neutron scattering facilities around the world.
Original language | English |
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Pages (from-to) | 63-70 |
Number of pages | 8 |
Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
Volume | 775 |
DOIs | |
State | Published - Mar 1 2015 |
Funding
The research at Oak Ridge National Laboratory was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy . S.Q. acknowledges the support of the Office of Biological and Environmental Research of the United States Department of Energy through the Center for Structural Molecular Biology at Oak Ridge National Laboratory . The authors thank Yuri B. Melnichenko for providing single crystal vanadium sample and also thank Yuri B. Melnichenko, Volker S. Urban, Sai Venkatesh Pingali and Christopher Stanley for their technical discussions and Kevin D. Berry for information about the detection efficiency of the LPSDs.
Keywords
- Linear position-sensitive detector
- Small-angle neutron scattering
- Solid angle correction
- Staggered array geometry
- Tube detector shadowing