Experiments

Production of Cometary Analog Material

	Fig. 1: Facility for the production of 'Cometary Analog Material' (CAM). A 'cometary analog' mixture of water and mineral dust is pumped through an ultra-sound disperser to avoid clumping. With compressed air the mixture is sprayed via spraying guns into a dewar-container with liquid nitrogen (LN2) at -196oC. The droplets freeze instantly and sediment down at the bottom of the LN2-container.
	Fig. 2 (above) shows CAM under the microscope. Fig. 3 (left): Grainsize distribution of a sieve fraction of CAM smaller than 630 mu-m. On four microscopic photographs the number of grains inside a size interval was counted out.
	Fig. 4: Setup for the production of ice spheres of mm-size. From a reservoir pre-cooled water drops through a glas tip into liquid nitrogen (LN2). At a temperature of -196oC the water drops freeze in a few seconds and sink down to the bottom of the LN2 container, where they can be stored without changing.
	Fig. 5: Size distribution of the ice spheres. The diameter is strongly depending on the size of the glas tip. But in a drop series, the diameter stays constant within a tenth of a mm.

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