Remote non-destructive monitoring of thermophysical properties using flash technique

The flash method for measuring thermophysical properties (TPP) has attracted wide-spread interest since it was introduced by Parker et al (1961). In an extension of this technique, we introduced a front-face flash-monitoring method (FFFMM) in which a radiative source delivering short heat pulses and an infrared detector to measure temperature excursion with time are positioned on the same side of an investigated object. In principle, front-face methods are more interesting than their rear-face alternatives because of the high signal-to-noise ratio. Moreover, front-face methods like the FFFMM are of vital importance in practice, e.g. when the rear side of the sample is inaccessible so that conventional transmission techniques cannot be applied. Time resolved thermograms allow depth profiling of the TPP of the sample using a dimensionless criterion of thermal homogeneity (DCTH), as described in our numerous reports. We showed that FFFMM can be applied virtually to thin films, coatings, layered materials, anisotropic materials and even to highly excited nuclear matter. Moreover, use of the DCTH gave us the possibility to exclude the influence of heat losses, of heat pulse duration, and of the depth of absorption of the applied heat pulse on the obtained TPP.