Setup for terahertz low temperature emissivity measurements

We report on first results obtained with the use of a new setup for direct passive measurements of the low temperature terahertz emissivity of different materials - metals, superconductors, and others. The setup allows estimating the level of noise originating from the thermal radiation of mirrors in terahertz space missions. This setup also makes it possible to develop the passive terahertz emissivity spectroscopy of different materials.