Geometric Area Measurements of Circular Apertures for Radiometry at NIST
J B. Fowler, Maritoni A. Litorja
NIST has established a geometric aperture-area measurement facility for circular apertures. The instrument consists of an interferometrically controlled XY translation stage for high-accuracy positioning and a video microscope for detection fo the aperture edge. Least-squares fitting of the edge points located along the aperture's inner circumference to the equation of a circle is used to determine the geometric area. In this paper we describe the measurement method, based on the work started and described by Fowler, Durvasula and Parr . Analysis and estimation of various contributions to the overall measurement uncertainty, including the effects of diffraction and partial coherence of light on the edge location are also discussed.
and Litorja, M.
Geometric Area Measurements of Circular Apertures for Radiometry at NIST, Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=841640
(Accessed July 3, 2022)