The interaction of ionizing radiation such as X-rays with biological samples causes damage to the samples. Recent work from our group with various protein crystals, peptides and amino acids showed that the formation of hydrogen upon irradiation is one of the major origins for radiation damage. We now want to test this hypothesis on DNA. Large Z-DNA crystals will be exposed with high doses of X-rays. Possible radiation induced structural changes to the DNA will be analyzed by subsequent single crystal neutron diffraction. The poor visibility of hydrogen atoms in X-ray data might be the reason, why X-ray experiments conducted in the field have failed so far. The experimental method has been well established in two previous experiments. With this experiment we expect to get a better understanding of radiation damage to DNA on the atomic level.