NIST Measurement Services: Regular Spectral Transmittance

Abstract

This document describes measurement services, instrumentation, and measurement techniques for regular spectral transmittance over the spectral range from 250 nm to 2500 nm at the National Institute of Standards and Technology. Section 2 explains the basic theory in deriving the transmittance, while the complex details of the derivation are reserved for the interested reader in Appendix A. A description of the reference instrument hardware, software, validation, procedures, and uncertainties are included in Section 3, while the same detailed information are described for the transfer instrument in Section 4. Appendices B and C contain a sample calibration report and sample data, respectively. Appendix D includes detailed instructions on how to request Regular Spectral Transmittance Calibrations. The measurement services are described to foster an understanding in the role this laboratory plays and the suitability to various customers. The instruments, measurement procedure, and uncertainties are described in sufficient detail to provide enough information to make comparisons with instruments at other laboratories.