Spectral tri-function automated reference reflectometer (STARR)

Description:

STARR is the national reference instrument for spectral reflectance measurements of spectrally neutral, non-fluorescent samples at room temperature.

The illuminator has two sources, a xenon (Xe) arc lamp and a quartz-tungsten-halogen (QTH) incandescent lamp, order-sorting filters, a shutter, a single-grating monochromator, a parabolic mirror, a chopper, and a polarizer. An in-plane goniometer is used for bi-directional measurements, meaning the sample normal, illumination axis, and receiver axis are all in a horizontal plane. The receiver is attached to the goniometer and has a precision aperture, a lens, and a photodiode detector, either silicon (Si) or extended indium-gallium-arsenic (InGaAs). An integrating sphere is used for directional-hemispherical measurements, and can accommodate Si and extended InGaAs photodiode detectors.

Specifications / Capabilities:

Conditions for reflectance measurements using STARR

	Bi-directional	Directional-hemispherical
	Specular	Diffuse
*Geometrical*
Illumination Angle	0° to +80°	0° to +80°	6° (specular included) 0° (specular excluded)
Viewing Angle	0° to +80°	0° to +80°	Hemisphere
Sampling Aperture	17 mm	17 mm	25 mm

*Spectral*
Wavelength	250 mm to 2500 nm	250 nm to 1100 nm	250 nm to 2500 nm
Bandwidth	14 mm	14 nm	14 nm
Polarization	0° to 90°	0° to 90°	Slight
Sample Size	50 mm to 300 mm	50 mm to 300 mm	50 mm to 300 mm

*Measurand*
Quantity	Reflectance	BRDF, Reflectance factor	Reflectance factor
Technique	Absolute	Absolute	Relative to PTFE
Range	0.001 to 1	0.001 to 1	0.001 to 1
Uncertainty (k=2)	0.1% to 0.2%	0.15% to 0.6%	0.15% to 0.6%

Associated Programs/Projects:

Spectrophotometry
Reference transmittance spectrophotometer (RTS)
Transfer spectrophotometer

Contact

Name: Catherine Cooksey
Phone: 301-975-6208
Fax: 301-975-6991
Email: ccooksey@nist.gov
Address:
100 Bureau Drive, M/S 8443
Gaithersburg, MD 20899-8443