Key-words: Calibration, IR thermometer, low temperature
The low temperature blackbody can be used for high precision calibrations of IR thermometers or as reference at temperatures down to -80°C using a vertical blackbody cavity inserted into a calibration bath with stirred methanol. The low temperature blackbody has a unique anti-ice purge system that operates using filtered compressed air from ambient to below -70°C for weeks.
The blackbody cavity is made of brass. The cavity is mounted in stainless steel adaptor with double o-ring seal. Outside surface of cavity is coated to reduce corrosion problems. Inside of cavity is coated with two types of black absorbing paint to increase the effective emissivity of the blackbody. The emissivity of the cavity is larger than 0.9990 for an inner diameter of cavity of 50 mm, 250 mm long and with bottom tilted 30°.
Special blackbody designs and complete tested systems can be delivered on request. Manual with details and instructions is available.
Options: Acreddited calibration, installation and training
Geometry and dimensions of blackbody cavity and adaptor. Heat conduction from bath to ambient is reduced using stainless steel adaptor with small wall thickness.
Picture of calibration bath mounted with blackbody cavity and purge system for reduction of ice formation at cavity opening and in cavity. A purge flow of dry air prevents ice formation in cavity and at opening. Dry air is distributed around blackbody opening via the anti-ice purge ring (black in picture).