High energy target facilities have been recognized as a critical challenge in development of future particle accelerators. Specifically, beam windows and targets in accelerators are exposed to radiation with very high energy protons, posing severe requirements on the materials used in these applications. Radiation can cause direct damage in the material and it leads to production of transmutation products (especially Helium), both phenomena having a potential adverse effect on the stability and durability of targets and windows. At high enough temperatures, Helium can aggregate to form gas bubbles, which in turn can cause significant dimensional changes (swelling), enable easy crack propagation, and eventually cause failure by fracture. On the other hand, if the temperature is too low, radiation damage accumulates in the form of internal defects (e.g., dislocations), leading to hardening and a decreased ductility of the material.
In this project we propose to develop an experimentally validated computational framework capable of predicting radiation damage evolution in beryllium, which is a promising material for applications in the current and future particle accelerators. In particular, our proposed multi-scale model is focused on Helium bubble formation and growth as a function of irradiation temperature and on the contribution of these bubbles to swelling. In addition, we propose to carry out a series of targeted ex-situ and in-situ dual-beam experiments using low-energy protons to provide critical data for validation of the model on the effects of radiation on Helium clustering, Helium bubble distribution, and dislocation loop density/size in proton irradiated Be.