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Insight into Neutron Focusing: the Out-of-Focus Condition



Boualem Hammouda, David F. Mildner, A. Brulet, S. Desert


A three-pronged approach is used to investigate neutron focusing for small-angle neutron scattering instruments. The three methods are analytical calculations, resolution measurements, and computer simulations. A source aperture containing a single small-size hole and a sample aperture containing multiple holes are used to produce multiple spots on the high-resolution neutron detector. Focusing elongates off-axis spots in the radial direction. The standard deviation for the size of each spot is estimated using these three approaches. Varying parameters include the neutron wavelength, the number of focusing lenses and the holes location on the sample aperture. Enough agreement for the standard deviation of the individual neutron beams was found between the calculations and the measurements to give confidence in this approach. Good agreement was found between the standard deviations obtained from calculations and simulations. Excellent agreement was found for the mean location of these individual spots. Recommendations are made for the optimization of neutron focusing.
Journal of Applied Crystallography


small-angle neutron scattering, neutron focussing, neutron lenses, mcstas, ray tracing


Hammouda, B. , Mildner, D. , Brulet, A. and Desert, S. (2013), Insight into Neutron Focusing: the Out-of-Focus Condition, Journal of Applied Crystallography, [online], (Accessed July 21, 2024)


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Created October 1, 2013, Updated February 19, 2017