Simulation Study of a Shield-Free Directional Gamma-Ray Detector Using Small-Angle Compton Scattering

Abstract Gamma-ray imaging is a technique for visualizing the spatial distribution of radioactive materials. has recently been applied to research on environmental restoration and decommissioning Fukushima Daiichi Nuclear Power Station (FDNPS). In this paper, we present an elemental technology study gamma-ray imager using small-angle scattering (GISAS), which intended application at FDNPS site. GISAS consists set directional detectors that do not require shield. study, investigated feasibility shield-free detector by simulation. The simulation result suggests measuring scattered-electron energies several keV scatterer detector, gamma rays with ultrasmall-angle could be selected. Using Compton kinematics, directivity about 10 deg may feasible. By arranging in array, expect able realize GISAS, small, light, capable quantitative measurement.