Full-size lamellar grating for the cosmic beamline at ALS-U

We have developed an innovative fabrication process for ultra-precise lamellar x-ray gratings, utilizing e-beam lithography, nanoimprinting, and isotropic wet etching. This process allows for the control of groove depth during the etching, achieving sub-nanometer accuracy and ensuring exceptional groove depth uniformity across the grating area. We successfully fabricated a full-size 179 lines/mm lamellar grating for the Cosmic beamline at ALS-U. The VLS grating pattern, measuring 175 × 20 mm², was etched onto a 200 × 40 × 50 mm³ silicon substrate from JTEC. At-wavelength measurements have confirmed the near-theoretical diffraction efficiency and bandwidth of the grating.