LumaSense Technologies M67 - Manual (Page 35)

M67, M67S Manual
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9.2 Emissivity compensation when using auxiliary windows
Auxiliary viewing windows are required in many situations to shield the INFRADUCER from very hot or hostile environments.
Such windows can be made from a variety of materials, which are consistent with spectral response codes as shown below:
WINDOW MATERIAL USEFUL WITH SPECTRAL
RESPONSE CODE
THICKNESS TRANSMITANCE
Pyrex Glass H, P, Q 1.5 mm 0.89
Quartz H, P, Q 1.5 mm 0.94
Calcium Fluoride E, P, Q 1.5 mm 0.94
Note that the window selected must conform to the spectral response code of the INFRADUCER chosen for a given application
and also must possess the strength and corrosion resistance required. No window transmits 100% of the thermal radiation
emitted by the target in any spectral band. The only method available is to offset the window transmissivity (supplied by
/XPD6HQVH for the spectral band of the target).
For example, if the target emissivity is 0.83 and the window transmissivity is 0.93, the INFRADUCER emissivity setting should
be 0.83 x 0.93 = 0.77 or 77%.
If the window transmissivity is not known, the emissivity calibration method of Section 9.1, page 33 may be used with the
window in place. This will ensure that the window transmissivity compensation is included in the calibration emissivity.