The Laser Flash Method measures the thermal diffusivity of a material, which is defined as a material-specific property characterizing the rate of transfer of heat from the hot side to the cold side of a material. Hence, a higher diffusivity represents a material that can transfer heat faster. ASTM E1461 and ISO 22007-4 specify requirements of the apparatus, test sample, and procedure for thermal diffusivity measurement by the laser flash method. This method assumes that the material thickness, density, and specific heat capacity are known from prior separate experiments. With these known factors, the thermal diffusivity can be measured, and then the thermal conductivity can be calculated. To perform the test, the disc shaped sample material is placed in the apparatus so that one plane is parallel to the laser energy pulse. The laser energy pulse is then applied to the sample so that its front side plane is heated up uniformly, and an infrared detector measures the time-dependent temperature rise at the back side of the sample. This method assumes that there is no heat loss laterally, and instead all of the heat travels in one-dimension. Using this measurement output, the thermal diffusivity of the sample can be determined, and then through the relationship between thermal conductivity, thermal diffusivity, density and specific heat capacity, thermal conductivity can be calculated as the equation shows.