1.1 This test method covers the determination of the thermal diffusivity of primarily homogeneous isotropic solid materials. Thermal diffusivity values ranging from 10-7 to 10-3 m2/s are measurable by this test method from about 75 to 2800 K. 1.2 This test method is a more detailed form of Test Method C 714, having applicability to much wider ranges of materials, applications, and temperatures, with improved accuracy of measurements. 1.3 This test method is intended to allow a wide variety of apparatus designs. It is not practical in a test method of this type to establish details of construction and procedures to cover all contingencies that might offer difficulties to a person without pertinent technical knowledge, or to stop or restrict research and development for improvements in the basic technique. 1.4 This test method is applicable to the measurements performed on essentially fully dense (preferably, but low porosity would be acceptable), homogeneeous, and isotropic solid materials that are opaque to the specimen of applied energy pulse. Experience has shown, however, that some deviation from these strict guidelines can be accommodated with care and proper experimental design, substantially broadening the usefulness of the method. 1.5 This test method can be considered an absolute (or primary) method of measurement, since no reference standards are required. It is advisable to use reference materials to verify the performance of the instrument used. 1.6 The values stated in SI units are to be regarded as the standard. 1.7 For systems employing lasers as power sources, it is imperative that the safety requirement be fully met.. 1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.