Study of Neutron Phase Diffraction Grating at Very High Resolution SANS Diffractometer KWS3

The very high resolution focusing SANS diffractometer KWS3, providing the Q-resolution of about 3.8×10Å at λ=12.8Å, is used for studies of the phase diffraction grating with the rectangular surface relief (the period of 3.3μm) obtained by photolithography and electrolytic deposition of Ni. Multiple diffraction orders are simultaneously recorded using a high-resolution 2-D position-sensitive detector. The presence of even diffraction orders in the angular spectrum is explained by non-rectangular trapezoidal-like distortions of the surface relief, which is reconstructed using the expansion in the Fourier series. The inclination of the grating leads to the increase in the phase modulation and, in turn, in higher intensity of high diffraction orders allowing for retrieving sharp features of the surface relief.