Micrometre-sized ice particles for planetary science experiments – CoPhyLab cryogenic granular sample production and storage

Abstract In this work, we present a comprehensive investigation into the production, characteristics, handling, and storage of micrometre-sized granular water-ice. The focus of this research is to provide well-characterized analogue samples for laboratory experiments simulating icy bodies found in the Solar System, particularly comets. These experiments are conducted as part of the CoPhyLab (Comet Physics Laboratory) project, an international collaboration aimed at studying cometary processes to gain insights into the underlying physics of cometary activity. Granular water-ice, along with other less abundant but more volatile ices, plays a crucial role in the ejection of gas and dust particles when comets approach the Sun. To facilitate large-scale laboratory experiments, an ice-particle machine was developed, capable of autonomously producing sufficient quantities of granular water-ice. Additionally, a cryogenic desiccator was designed to remove any residual moisture from the ice using liquid nitrogen. The resulting ice particles can be mixed with other materials and stored within the desiccator or a cryogenic transport can, enabling easy shipment to any laboratory, including via air transport. To analyse the ice grains, cryogenic scanning electron microscopy was employed to determine their particle shape and size-frequency distribution. These analyses contribute to a better understanding of the properties of granular water-ice and its behavior under cryogenic conditions, supporting the objectives of the CoPhyLab project.