The Radiation Research Core Facility provides a comprehensive irradiation service, including the exposure of small animals, mammalian cells in culture, microorganisms and macromolecules to gamma-rays, x-rays and 254 nm UV light. Research goals are diverse and include such tasks as creating double strand breaks or bulky lesions in DNA, irradiating mice before injection of cells to test tumorigenicity, creating transformed cells, preparing feeder layers for tissue culture, irradiating mice specifically in their eyes to analyze cataractogenesis, and measuring radiosensitivity of yeast, mouse, hamster or human cells.