Summary The central theme of this P01 is to investigate the role of proton/electron/carbon radiation dose rate in normal tissue damage and tumor killing. Delivery of precise doses of radiation with varying dose rates to experimental tumors and normal tissue in animal model systems is a critical task of each project. This Core will provide the dosimetric infrastructure to ensure that each participating institution and radiation modality (electron, proton, and carbon) will have consistent and robust FLASH doses. The proposal includes a multi-disciplinary group with radiation oncologists and biologists who will work very closely with physicists to ensure procedural consistency for FLASH radiation. Reliable and consistent irradiations and determination of dose and dose rate are the primary functions of the Core. The specific aims to enhance capabilities towards this outcome are: Specific Aim 1: Develop and maintain a dosimetry infrastructure for accurate determination and calibration of absorbed physical dose, beam delivery sequence, dose rate and dose-time structure across experimental systems. Specific Aim 2: Develop animal specific treatment techniques and dosimetric support systems. Specific Aim 3: Develop interlock and irradiation logging systems for safe and reproducible experiments across all projects.