NIST Reference Reflectometer: STARR Facility
The Spectral Tri-function Automated Reference Reflectometer (STARR) is the national reference instrument for spectral reflectance measurements of spectrally neutral, non-fluorescent samples at room temperature. STARR performs absolute measurements of bi-directional reflectance on samples with widths from 50 mm (2 in) to 300 mm (12 in). The measurements are all in-plane, meaning the sample normal, illumination axis, and receiver axis are all in a horizontal plane. Diffuse reflectance can be measured at wavelengths from 250 nm to 1100 nm, while specular reflectance can be measured at wavelengths from 250 nm to 2500 nm. The fundamental quantity for bi-directional reflectance measurements is the bi-directional reflectance distribution function (BRDF), from which the reflectance and reflectance factor can be calculated. STARR also performs relative measurements of directional-hemispherical reflectance on samples with widths from 50 mm (2 in) to 300 mm (12 in). The primary standard is pressed polytetrafluoroethylene (PTFE). The reflectance can be measured with either a 6º or 0º angle of illumination, specular component included or excluded, respectively, at wavelengths from 250 nm to 2500 nm. The fundamental quantity for directional-hemispherical reflectance measurements is the reflectance factor.
For technical information or questions, contact: Maria E. Nadal Phone: (301) 975-4632 FAX: (301) 869-5700 maria.nadal@nist.gov OTD Home Page   |   Site Comments Online: September 1997  -  Last updated: May 2003