When thermal conductivity and diffusivity are measured with a thermal constants analyzer, sensors of different designs are being used. Sensors are primarily made of nickel foil, arranged in a double spiral, sandwiched between two thin sheets of insulating material. For experiments between 30 and 450 K, the polyimide Kapton has been used as the insulating material. For experiments being performed at temperatures above 450 K, but below 1000 K, Mica can be used as ...