LumaSense Technologies M67 User Manual

Page 35

M67, M67S Manual

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.

This manual is related to the following products:

M67S