The high power CO 2 laser study on system of traceability dynamic calibration

Abstract

In the paper, a principle is proposed, that is, a high frequency modulated high power CO₂ laser is used as the driving source to heat up the sensor. Using the continual beam and the pulsed beam sent out by the same laser in the same system to carry on the static calibration of the infrared detector and the dynamic calibration of the temperature sensor to be checked, the differences in the environment of the sensor installing and the error caused by the change of thermo physical property can be avoided. Thus the difficult problem of traceable temperature dynamic calibration is solved. Tellurium-cadmium-mercury infrared detector which has good response to the CO₂ laser beam of 10.6μm wavelength is used to measure the surface temperature time (72μs) excited by the CO₂ laser. This dynamic calibration system was used to test the response times of two kinds of thermocouples. The experimental results have shown that this calibration system can be used to calibrate transient surface temperature sensor with a time response of the seconds to sub-milliseconds order and 2000°C. Many thermocouples of company Omega have been tested on the system. The experimental results show that the new calibration method can be used to calibrate surface temperature sensors.