High Accuracy Aperture Area Measurement Facilities at the National Institute of Standards and Technology

Published

January 1, 1998

Author(s)

J B. Fowler, R Durvasula, Albert C. Parr

Abstract

The uncertainty in the measurement of aperture area can limit high-accuracy radiometric and photometric measurements. Relative total uncertainties in some measurements have now been determined at or below the 0.1% level, making substantially smaller aperture-area measurements uncertainties necessary. The National Institute of Standards and Technology (NIST) has recently implemented an absolute aperture-area measurement facility and a relative aperture-area measurement facility; the two facilities together are designed to determine aperture areas with low uncertainty. The absolute instrument measures the aperture-area using optical edge detection, along with high-precision positioning of the optical edge relative to the sensor, resulting in an expected relative combined standard uncertainty of less than 10^-4. The relative instrument uses optical flux transfer to compare aperture areas and also has an expected relative combined standard uncertainty, of less than 10^-4. The absolute instrument will be used to measure the area of standard apertures for use with the relative instrument.

Citation

Metrologia

Volume

35

Pub Type

Journals

Keywords

absolute, aperture, area, Flux-transfer, high-accuracy, non-contract, relative

Citation

Fowler, J. , Durvasula, R. and Parr, A. (1998), High Accuracy Aperture Area Measurement Facilities at the National Institute of Standards and Technology, Metrologia (Accessed July 20, 2025)