A reflectance spectrometer/environmental chamber for frosts

As part of a study of frost spectral properties, a low incident energy, near ir reflectance spectrometer has been designed and built as an integral part of an environmental chamber. The total incident energy on the sample from the monochromater and cooled chamber, 4 x 10(-3) W cm(-2), is one to two orders of magnitude less than in previous ir spectral measurements of frosts and avoids thermal metamorphism of the sample. All supports, connections, and windows are mounted in the chamber lid allowing very simple, readily interchangeable chambers to be used. This permits growth of samples under a variety of controlled conditions and allows spectral measurements over a wide range of inclinations. The apparatus allowed photography and access to the sample so that sample density, thickness, grain size, and composition of H(2)O-CO(2) frosts could be determined.