Studies of Nuclear Processes in Scintillator Materials Using Event-Based Cameras

Recently developed event-based camera systems offer a novel approach for scintillator characterization and scintillator-based applications such as radiographic imaging and spectroscopy. Event-based cameras can capture the spatial and temporal information of emission light from scintillators induced by particle interactions within the scintillator. Currently (without the event-based approach), radiographic and spectroscopic signals are integrated from a multitude of events that are triggered from incident x-rays and neutrons. Simulations of these integrated signals are challenging because of the complex nature of the processes in the scintillator. X-rays and neutrons produce secondary particles, e.g., electrons and protons, through atomic and nuclear reactions. The secondary particles interact with scintillator materials to produce emission light. Simulation codes like Geant4 are designed to track particles and secondaries with detailed spatial and timing information. However, the abundance of information from detailed simulation runs are mostly useless when comparing simulated data to measured data since the events are integrated. With event-based camera systems, where it is possible to capture the spatial and temporal information (~1.6ns) of emission light, direct comparison between detailed simulation tracks and measured tracks can be made. Nuclear reaction data plays a critical role in the new approach to scintillator characterization and modelling. This is especially true for incident particles with unique spectral characteristics. We will present results from comparisons of Geant4 simulation runs to measured data. We will discuss some of the open questions and highlight the gaps in the data libraries.



^*This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344