Far Infrared Transmission and Reflection of Irtran 1 through Irtran 6 at Low Temperatures.

Transmission and reflection measurements in the infrared region between 340 and 40 cm(-1) are presented for Irtrans 1-6. Measurements have been performed at room temperature and at liquid nitrogen and liquid helium temperatures.

Low Temperature Filter for Photometry in the 20-micro Atmospheric Window.

In a search for a filter for a 20-micro astronomical photometer the reststrahlen reflection of Irtran-1 and a ZnO pellet has been measured at low temperatures in the 15-50-micro range. With a mean reflection of 82% between. 16 micro and 22.3 micro the Irtran-1 material appears to be a efficient low temperature filter suitable for this spectral window, especially when using several reflections.