7th International Conference on Matter and Radiation at Extremes (ICMRE2024)

Imaging of gamma-ray lines from inertial confinement fusion (ICF) experiments provides fruitful information for studying implosion dynamics. For indirectly driven DT implosions, the 16.75 MeV gamma-ray line produced in DT fusion reactions is a direct signature of total fusion yield and 4.44 MeV gamma-ray line produced by inelastically scattering between fusion neutrons and the remaining ablator of the fusion capsule is directly related to the areal density of the capsule. In this paper, we present an energy-selective gamma-ray imaging system that allows for precise imaging of gamma-ray line from specific nuclear reaction in ICF experiments. The proposed system comprises three components: a Beryllium foil to convert gamma-rays into electrons via Compton scattering, a double-bend beam transport system that spectrally selects and spatially resumes electron information after the foil, and a position-sensitive detector to record the position distribution of electrons. Design considerations and optimizations are detailed. Monte Carlo simulations are accomplished to study the performance in imaging 4.44 MeV gamma-ray line from a broad-band spectrum and the energy resolution and spatial resolution for 4.44 MeV gamma-ray line from a broad-band spectrum achieve 0.41 MeV (FWHM) and 1 mm respectively, under the detection efficiency of 8.5×10^-5 cm², demonstrating the potential of the proposed system in future high-yield ICF experiments.

ion optics,gamma-ray imaging,energy-selective imaging,ICF diagnose