Radioactive nanomaterials play important roles in many different fields of science, whether they are natural, incidental or engineered. From an environmental and health impact assessment perspective, refractory radionuclides such as U and Pu released from nuclear sources, including nuclear weapons tests and military or civilian nuclear accidents, are typically associated with radioactive particles. As a result of particle weathering, radionuclides originally associated with large particles or fragments may also occur as submicron and nanoscale particles, with biological uptake properties and environmental impact potentially different from those of ions. There is a need for a better understanding of the sources, transport, ecosystem transfer, and toxic effects of radioactive particles. NanoSIMS provides new possibilities for detailed characterization of radioactive particles and colloids as well as sub-cellular imaging of elemental and isotopic biodistributions of particles-derived radionuclides following exposure in the environment or in laboratory-based toxicity tests.
Beyond the scope of health and environmental impact, the sources and characteristics of particles of fissile materials are important from a nuclear security perspective and play a major role in nuclear forensics. Nuclear forensic particle analysis provides information regarding the origin of the nuclear material and its processing history. As a surface analysis technique, the NanoSIMS can characterize the isotopic compositions and elemental compositions of a variety samples types, from micrometric dust collected in soil after a nuclear accident, seized fuel pellets from power plants, or geologic samples processed by detonation of a nuclear device and contaminated by its products.
The NanoSIMS appears as a versatile tool to characterise the isotopic and chemical signature of a large variety of radiological materials at a sub-micrometer scale. As a unique facility in the Nordic country, the NanoSIMS facility will provide a step-change in deciphering the chemistry and isotopic compotion of radioactive materials pertinent to the environmental, health, and nuclear forensic fields.
Several activities will be executed for this proposal:
1. Development of methods for quantitative imaging of isotopic ratios in particles and solid samples. Development of a library of standards including in-house standards with epoxy or resin matrices containing known concentrations of radionuclides (with focus on U and Th) for calibration and standardization of the NanoSIMS method and used for environmental and biological studies. The concentrations of U and Th in the standards will be determined by ICP-MS by participating labs.
2. A NanoSIMS workshop will be organized on the facility site in Göteborg.The workshop will consist first of a theoretical part focusing on NanoSIMS principles and lectures from specialists on correlated techniques like AMS, ICP-MS, gamma and X-ray spectroscopy, electron microscopy, and second, of a practical part focusing on NanoSIMS training on instrument with data acquisition, data mining, data interpretations, isotopic imaging of radionuclides of a few samples along with certified materials or standards to demonstrate the capabilities of the NanoSIMS.
3. Creation of a network of skilled and competent users of the NanoSIMS capabilities, developing and mastering measurement protocols applied to the isotopic measurement of actinides in various matrices including bio-distribution in exposed biota, artificial, (fuel pellet, certified reference material) and natural samples.
4. Exchange of knowledge and experiences among Nordic scientists of different fields for analysis of radionuclides in the environment using different techniques, which will strengthen the Nordic competence in environmental radioanalysis.
As a unique facility in the Nordic country, the NanoSIMS will contribute in deciphering the history of radiological isotopes in both environmental, health and nuclear forensic fields.