A refractive focusing lens system for small-angle neutron scattering

Simple neutron optics measurements have been performed using optical-quality concave lenses as a function of neutron wavelength on a 30 m SANS instrument. The variation in the width of the beam spot on the detector at wavelengths different from the focused condition has been observed. The movement of the beam on the detector when the centerline of the lens combination is shifted from the incident-beam centerline has also been observed. These results are compared with theoretical predictions.