THz continuum absorption of H2O ice particles at different temperatures
The submillimeter-wavelength absorption of water ice and its temperature dependence are still poorly known. We have made use of facilities at IGEP Braunschweig to produce thick layers of water ice particles by freezing of micron-sized droplets in a LN2-temperature environment. While these layers were brought to increasingly warmer regions of the experiment, the absorption for submillimeter radiation was measured using a time-domain THz spectrometer. From the measurement of the pulse delay, the packing density of the particles was determined and the measured absorption was compared to simulations using bulk optical constants and effective-medium models.