iMASS: Evolved NRF Simulations for More Accurate Detection of Nuclear Threats

The intelligent Model-Assisted Sensing System (iMASS) combines computer simulated nuclear resonance fluorescence (NRF), real-time Monte Carlo analysis, and signal data processing for the detection of nuclear materials hidden in cargo containers. There are on average nine million cargo containers entering the US every year. Fast and robust scanning for nuclear materials and explosives is of the outmost importance for a country’s security and safety. This paper presents the Geant4 platform development for direct application in nuclear material detections, including: an improved module to simulate the bremsstrahlung spectra, a model for NRF simulations addressing the Compton continuum background that would be found during an actual scan, and the improvements in output data interpretation. The dynamic flexibility of Geant4 and the ability to be sped up with field programmable gate array (FPGA) and parallelization is also described.