Electron Microscopy Sciences Grating – Ronchi Ruling 100 Lines Per mm . — 50 mm X 50 mm B270 Glass, 1.5 mm Thick, Ruled Over 30 mm Wid

Electron Microscopy Sciences Metallic grating pattern on glass squares with opaque lines approximately 50% of the pitch. Stock items are on 50 mm x 50 mm squares of glass 1.5 mm thick. The glass is b270 with refractive index of 1.52. Mutually perpendicular pairs produce a screen of square apertures. Vacuum deposited chrome gratings on glass substrate. Typically used for testing of resolution, field distortion and parfocal stability, but may be paired to provide interference patterns. - EMS