What Living organisms are constantly exposed to radiation, which can be both beneficial (radiotherapy) and detrimental (radiation damage). The goal of this project is to unravel how radiation damage occurs on the molecular scale - and how we may control it for targeted cell protection or destruction. Why Today we know that radiation damage of living tissue such as irreparable strand breaks in DNA, is mainly caused by secondary species instead of the primary radiation. But the elementary processes of formation of secondary species, in particular slow electrons, are only now being explored. To devise new strategies for protecting against radiation damage or for using it in a controlled way, it is essential to understand it in detail and on the scale of atoms and molecules. How Using synchrotron radiation, we will probe isolated biomolecules and specifically designed complexes thereof with regard to their response to ionizing radiation (ultraviolet up to x-ray). By detecting electrons, ions and photons created by the radiation, we will get detailed insights into the elementary steps leading to radiation damage. SSR The main long-term aspect of SSR is that the project will contribute to the fundamental understanding of radiation-induced damage of biological matter. On the one hand side, this will help developing new strategies to protect living organisms against ionizing radiation. Undoubtedly, protection of humans, animals and plants against ultraviolet sun light, medical x-rays, cosmic radiation, and radioactivity has considerable societal relevance. On the other hand, new approaches to radiation therapy may arise mainly from improved capabilities to control the ionizing radiation (photon energy, intensity, time structure). New instrumentation and data analysis software will be developed in the course of the project paying particular attention to their potential for patenting and commercialization.