Standard Reference Materials 2053, 2054, 2055, and 2056 are transmission filters designed to have nominally neutral attenuation over the 2 mm to 25 mm wavelength region, with optical densities near 1, 2, 3, and 4, respectively. The filters are made of polished single-crystal Si substrates, 25 mm in diameter and 0.25 mm in thickness, with thin Ni:Cr or Cu:Ni coatings appropriate for the given attenuation level. They are intended to be used for checking the accuracy of the ordinate scale of infrared spectrophotometers. The regular spectral transmittance of each filter has been measured with 8 cm-1 resolution using an FT-IR spectrophotometer. The uncertainty in transmittance of each filter has been determined, including both type-A (statistical) and type-B (systematic) components.
Citation: Special Publication (NIST SP) - 260-123
NIST Pub Series: Special Publication (NIST SP)
Pub Type: NIST Pubs
attentuation, FT-IR spectrophotometer, infrared filter, optical density, transmittance, uncertainty analysis