Monte Carlo Simulation with CAD Interface for Calculation of 3D Maps of Residual Dose

Residual radiation caused by activation radioactive isotopes can stay in facilities, on instruments and clothes from several days to many years and there is a need to have a tool for automatic simulation of 3D residual dose distributions in time. Several well-tested high-fidelity Monte Carlo codes can be used to perform such simulations, but they include many ômanualö programming and integration tasks. Moreover, they often use approximate representation of complex CAD geometries and lack user-friendly interfaces to set up and execute the required workflows in a streamlined and errorproof fashion. This problem is being addressed by developing a framework for streamlined calculation of residual dose using the Geant4 Monte Carlo code. We propose to augment a desktop application system that allows complex geometries from CAD to be used in simulations without programming knowledge and manual editing of input files and to run simulations on a variety of computing resources. In Phase I, Tech-X developed software for translating CAD to MARS15 and Geant4 inputs; extensions of MARS15 and Geant4 to increase automation of residual dose calculations, and prototype user interfaces to setup and visualize simulations. Tech-X developed RSim with tools for CAD translation, healing, and scoring mesh generation. All teams have automated of simulations of residual dose in CAD geometries. RSim interfaces for: CAD geometries enriched simulation, creating input files, running Geant4, converting output, and visualizing data for residual dose calculations were created. RSim runs locally on the desktop, remotely on clusters, and on the Amazon Cloud through the browser. We plan to: (1) enrich RSim technical features by making improvements to the GORAD features such as bias techniques and output particle trajectories, controlling the automatic run of simulations based on a desired errors, and probe scorers; (2) increase awareness of RSim commercial value by demonstrating at scientific technical meetings and developing the company website, showcasing RSim with new examples and better documentation, and outreach to the target markets; and (3) improve the RSim user experience and robustness, performing benchmarking between RSim/Geant4 and other established codes (such as FLUKA), and improve running on the Amazon Cloud including high-performance cloud clusters. The developed application will be of immediate use to the US National Laboratories doing research in High-Energy Physics, Nuclear Physics, Nuclear Energy, Fusion, and Non-proliferation: FNAL, JLab, SLAC, ORNL, SNS, BNL, and PPPL. Commercial applications include aerospace, nuclear energy, nuclear medicine and radiotherapy applications and nuclear waste management in these sectors.