Abstract
The National Metrology Institute of Japan designed a system to supply reliable thermal diffusivity data efficiently and quickly to society. The system was founded on the technology for thermal diffusivity measurement by using a laser flash method, by establishing a metrological standard and reference materials, and by standardization of measurement technology. Uncertainty in measurement of thermal diffusivity with practical apparatus by the laser flash method was reduced using elemental technologies to homogenize the laser beam, a fast response infrared thermometer, and a curve fitting method to analyze temperature response curves. JIS and ISO standards were established or revised based on the developed technologies. In addition, methods to evaluate uncertainty in measurement of thermal diffusivity and calibration procedure by reference materials are described in the latest update of the JIS standard for the laser flash method. A procedure to obtain intrinsic thermal diffusivity is also described. Traceable thermophysical quantity data produced by this social system can be accumulated in a database system developed and operated by the National Metrology Institute of Japan (NMIJ), which is accessible via the Internet.
