A NEW METHOD FOR ANALYZING LOW VELOCITY PARTICLE IMPACTS

Particle detection and characterization by piezoceramic acoustic detectors was tested for lowvelocity impacts of ice/dust particles with respect to comet simulation (KOSI) experiments. In these experiments ice/dust samples consisting of water and carbon dioxide ice, as well as mineral dust grains are irradiated with simulated solar light. As a consequence the sample emits particles in a wide size range up to a few millimetres. To detect these particles and to get information on their physical parameters like size, momentum, mass and velocity, acoustic detectors are used. It has been shown that piezoceramic detectors are suitable for characterizing low-velocity particle impacts at speeds of about 1m s- and at particle diameters > 200 μm. Agglomerates with high porosities (filamentary sublimate residues) show only weak and complex piezoelectric signals because of their inhomogeneous momentum transfer to the acoustic detector during impact processes. It has been shown that at least some fraction of emitted particles in the KOSI experiments still contains a large amount of icy constituents. © 1990.