Apparatus for determining the thermal conductivity of a solid material

摘要

The sample 1 is heated by means of a laser flash and the change in temperature at the surface of the sample 1 facing the differential temperature pyrometer 6 is measured. An optimum temperature resolution in a temperature range from 20 to 3000 DEG C is achieved by using three detectors 8, 9, 10 comprising different detector materials. To screen the pyrometer 6 from the laser flash, a second camera shutter 11 closes the beam path to the pyrometer 6 for 2 ms. A first camera shutter 7, which is inverted with respect to the second camera shutter 11, simultaneously opens the beam path from the laser apparatus to the sample 1 and then keeps any stray light from the sample 1 out of the laser apparatus 4. Advantages are the wide temperature range from 20 to 3000 DEG C accompanied by high temperature sensitivity, the short dead time prior to the start of the measurement, the fact that the measuring signal is free of radiation components from the laser apparatus 4, and the fact that the pyrometer 6 does not require screening from the stray laser light. <IMAGE>