Conceptual design of a gamma-to-electron energy-selective imaging system for high-flux MeV gamma rays

A novel design for energy-selective imaging of high-flux gamma rays in the multi-MeV range is presented. The proposed system is based on gamma-to-electron conversion and energy-selective imaging of the electrons. The main components of the system include a low-Z foil that converts MeV gamma-ray photons into electrons through Compton scattering, and a double-bend beam transport system that performs energy selection and pointto-point imaging for the electrons. The image of the energy-selected electrons can be used to obtain spatial information for incident gamma rays of interest energy, enabling energy-selective imaging of broad-spectrum gamma-ray beams. Design considerations and optimizations are detailed. Monte Carlo simulations are conducted to evaluate the performance in energy-selective imaging of broad-spectrum gamma-ray beams. The energy resolution for 4.44 MeV gamma-ray achieves 0.41 MeV (FWHM) with a quantum efficiency of 2.5 x 10-6-6 e/ gamma, and the spatial resolution is approximately 1 mm and 2.5 mm within a 60 x 60 mm field of view in the horizontal (x) x ) and vertical (y) y ) directions, respectively.