ASD Document 600541 Rev. G 40 TerraSpec® User Manual
www.asdi.com Chapter 6 Field Measurements
Reflectance = Energy reflected from target/energy incident on target
6.4.2 Maintaining Spectralon References
Spectralon is an optical standard and should be handled in much the same way
as other optical standards. Although the material is very durable, care should
be taken to prevent contaminants such as finger oils from contacting the
material’s surface. Always wear clean gloves when handling Spectralon.
To clean a lightly soiled Spectralon white reference
If the material is lightly soiled, it may be air brushed with a jet of clean dry air
or nitrogen.
WARNING! DO NOT use Freon.
To clean a heavily soiled Spectralon white reference
Sand the Spectralon material under running water with a 220-240 grit
waterproof emery cloth or sandpaper until the surface is totally hydrophobic
(water beads and runs off immediately).
Step 1 Use a flat surface, such as a thick, flat piece of glass.
Step 2 Place the glass into the sink.
Step 3 Place 220 grade wet sandpaper onto the glass.
Step 4 Gently move the Spectralon reference in a figure 8 motion on the sandpaper,
using water as needed to wash away the thin layer that is sanded off.
Step 5 Blow dry with clean air or nitrogen or allow the material to air dry.
Step 6 If the material requires high resistance to deep UV radiation, the piece should
be prepared as above, then either of the following two treatments performed.
1 Flush the Spectralon piece with >18 milli-ohm distilled, deionized water
for 24 hours.
2300 0.972
2400 0.955
2500 0.950
Table 6-1Labsphere's published reflectance data for uncalibrated Spectralon (+/- 0.5%)
Wavelength (nm)
SRM-990 “Uncalibrated”
Spectralon Reflectance
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