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Reference Integrating Sphere for Spectral Reflectance
The reference integrating sphere performs directional-hemispherical reflectance measurements of spectrally neutral, non-fluorescent samples at room temperature. It serves as the national reference instrument for directional-hemispherical reflectance measurements. The sphere uses a tunable, quasi-monochromatic system for illumination of the sample that is shared with the Robotic Optical Scattering Instrument (ROSI) and broadband detection. Directional-hemispherical measurements are made relative to a calibrated standard, pressed polytetrafluoroethylene (PTFE).
Specifications/Capabilities
Conditions for directional/hemispherical reflectance measurements using the reference integrating sphere:
|
Geometrical |
|
|---|---|
|
Illumination Angle |
8° specular included |
|
Viewing Angle |
Hemisphere |
|
Sample size |
Minimum 45 mm |
|
Sampling Aperture |
10 mm |
|
Spectral |
|
|
Wavelength |
250 nm to 2400 nm |
|
Bandwidth |
14 nm |
|
Polarization |
Linear or unpolarized |
|
Measurand |
|
|
Quantity |
Reflectance Factor |
|
Technique |
Relative to PTFE |
|
Range |
0.001 to 1 |
|
Relative uncertainty (k=2)* |
0.4% |
*The listed relative uncertainty is the minimum expected value. Actual values vary due to sample-dependent factors.