Speaker
Description
Neutron reflectometry (NR) is a powerful technique to explore the structure of the surface and interfaces of materials. In a typical NR experiment, the sample surface/interface must be uniform over an area of more than 10 cm2 due to the size of the neutron illumination. Therefore, conventional NR has been inapplicable for the structure analysis of the sample with in-plane inhomogeneity. We developed an NR imaging technique to examine the position-dependent NR profile. The spatially resolved NR profile perpendicular to the beam axis is directly measured with the sheet-like neutron illumination and a position-sensitive detector. An NR image is reconstructed by a computer tomography (CT) calculation for the reflectivity at a given momentum transfer, q, dependent on the in-plane rotation angle of the sample. The spatial resolution of the NR-CT method is determined by the collimation condition of the neutron beam and the resolution of the detector. With a neutron reflectometer SHARAKU in J-PARC, the achievable resolution is ca. 0.6 mm. The CT reconstruction images based on the reflectivity at various q provide the NR profile at each image pixel, and the depth structure of the neutron scattering length density can be evaluated at a local area as small as 0.1 mm2. In this presentation, the application of the NR-CT to the analysis of laterally inhomogeneous interfaces of a polymer system is also demonstrated.
| Please select the related topic from the list below | Thin films and interfaces in soft matter and materials science |
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