Final Activity Report Summary - CERIS (Cold Electron chemical Reactions and physical Interactions with Solids: fundamental experiments on damage and synthesis of biomolecules) Many agents may provide insight into the structure and properties of materials which form the basis of both the natural world and modern technology. Among these agents, electrons, the tiny charged particles which are the constituents of all atoms and molecules, play a dominating role. We freed electrons from their atoms, using energetic light from the synchrotron radiation source at Aarhus University, Denmark, and unified these electrons into beams. Our first achievement was to create electron beams at extremely low energy, in a regime in which other experiments could not work, by a factor of a hundred. We investigated how these beams interacted with fundamental compounds, such as ice or acetic acid. Our aim in doing this was twofold. In the first place, electrons impinge on ices, which include all condensed compounds in the natural world, as for example in the cold upper atmosphere of the Earth and other planets and beyond the solar system in outer space. In the second place, knowledge of interactions of electrons with solid material should underpin emerging technologies in the nano-sciences, particularly in electron-controlled chemical lithography in which chemical patterning might be achieved in the future through electron beams. Our second major achievement was to gather data on how very low energy 'cold' electrons passed through, e.g. in water ice or in acetic acid ice. Acetic acid was found to gather cold electrons very efficiently and prevent their passage, with the material being strongly charged. Water ice, the most prevalent ice in the natural world, demonstrated a most extraordinary and unexpected property. In contrast to other ices, water ice allowed for the passage of electrons with 100 % efficiency at very low energy and was transparent to electrons. This electrical property of water ice could have important consequences regarding our understanding of the role of ice-covered particles in nature and future nano-electronics.