1994 Volume 8 Issue 3 Pages 143-148
A high speed infrared radiation thermometer was developed for laser flash thermal diffusivity measurements. The radiation thermometer consists of an InSb detector, a reflection type finder, a reference blackbody and a simple infrared optical system. The elimination of a mechanical chopper from the optical system realized the response time at temperature detection as short as 1μs.
The radiation thermometer is calibrated in the temperature range from 0 to 300°C, where nonlinear dependence of the output on temperature must be corrected for accurate thermal diffusivity measurements. The measurable temperature range can be extended up to 1500°C by attenuation of incident radiation with an iris diaphragm. The noise equivalent temperature difference is 0.039°C at room temperature for an integration time of 1.6μs.
A thermal diffusivity measurement with the half rise time as short as 1.85ms and the maximum temperature rise of 6.6°C is feasible with a laser flash system using this infrared radiation thermometer.