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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 | |
|---|---|
| Spectral | |
| Measurand | |
| Illumination Angle | 8° specular included |
| Viewing Angle | Hemisphere |
| Sample size | Minimum 45 mm |
| Sampling Aperture | 10 mm |
| Wavelength | 250 nm to 2400 nm |
| Bandwidth | 14 nm |
| Polarization | Linear or unpolarized |
| 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.