Abstract: An instrument for determining thermophysical properties of a solid sample of uniform thickness is disclosed. The instrument comprises a furnace, an elliptical mirror outside the furnace, a light source at one focus of the elliptical mirror that is closest to the elliptical mirror, a beam guide having one end at the other focus of the elliptical mirror and the other end inside the furnace, a sample holder inside the furnace capable of holding at least two diffusivity samples with the front and back surface of a sample exposed, an indexing system for moving the sample holder so as to place samples held by the sample holder in the path of light leaving the beam guide, and an infrared detector for quantifying changes in the temperature of the back surface of a sample that is in the path of the light. Methods for determining the thermal diffusivity, specific heat capacity, thermal conductivity, coefficient of thermal expansion, density, and temperature of a sample using this instrument are also disclosed.