Laboratory simulation improvements for hypervelocity micrometeorite impacts with a new dust particle source

Cosmic dust, consisting of micrometeoroids with grain sizes below 200 μm, is investigated in situ with impact ionisation detectors on spacecraft measuring the electric charge of the ions produced by the impact of a particle at a speed above 1 km/s. Time-of-flight mass spectrometers incorporated into the detectors determine the chemical components of an impacting projectile. To calibrate the dust detector instruments particles with similar compositions and speeds as the expected micrometeoroids are needed as projectiles in the laboratory. The Heidelberg dust accelerator, a 2 MV electrostatic accelerator, equipped with a special dust particle source, provides micrometer-sized particles as projectiles for hypervelocity impact experiments. s paper, we describe a new dust source that has been developed to expand both, the charge and impact speed ranges, and to use various projectile materials. We present the results of accelerating particles with grain sizes between 0.02 and 6.0 μm, made from metals, carbon, and polymer-coated latex using the new dust source at the 2 MV accelerator and at a test setup with 20 kV acceleration voltage. With this dust source we achieved also a higher charging of iron particles (13.4 C/kg for a 1 μm particle) than with our old source (11.9 C/kg), resulting in speeds up to 18 km/s for a particle of 0.2 μm size, and 100 km/s for a particle of 0.02 μm size.