The theory and implementation of an experiment aimed at studying heat behavior on a very short time scale (up to 10(-11) s) is explained. A detailed thermal model, based on the hyperbolic heat conduction equation, shows that a non-diffusive (or even oscillating) heat behavior with relaxation time influence (in Vernotte’s meaning) needs to be considered. There is also some discussion about the theoretical problem of compatibility with the second law of thermodynamics. The first results from the Validation stage, concerning the ’slow’ version of the experiment (time scale : 10(-9)-10(-6) s), are presented. Work on the ’fast’ version is currently in progress.