Scattering coded imaging system and its optimal design

Abstract [Background] With the development of high-current pulsed power devices, intense pulsed gamma radiation measurement and diagnostic techniques face new challenges as conventional methods are limited in spatial arrangement and interference resistance. [Purpose] This study aims to propose a scattering coded imaging system for accurately measuring the dose field intensity distribution of intense pulsed gamma radiation, with an optimized design of the coded aperture to enhance the imaging performance of the system. [Methods] Firstly, a thin scattering target was used to reduce gamma ray intensity, protecting the imaging detector from dose rate damage while minimizing changes to the pulsed radiation field parameters. Secondly, the ring aperture was chosen as the coded aperture for the imaging system, with its inner diameter, ring width, and thickness optimized through the application of genetic algorithms in conjunction with the MCNP code. Thirdly, to validate the optimization results, the spatial resolution of the imaging systems corresponding to the optimized ring aperture, ring aperture without optimal parameters, and pinhole aperture was quantitatively evaluated using a line-pairs source of varying widths. Additionally, the imaging quality of the three systems was compared under conditions of misalignment and non-uniform source intensity. Finally, bilateral filtering was applied to the reconstructed images to enhance contrast and achieve a more uniform distribution. [Results] The genetic algorithm optimization shows that the optimal reconstructed image correlation coefficient is achieved with an inner diameter of 2.730 cm, a ring width of 2.147 cm, and a thickness of 4.230 cm. The imaging system employing the optimized ring aperture as the coded aperture demonstrates superior spatial resolution compared to both the ring aperture without optimal parameters and the traditional pinhole aperture. Additionally, under conditions of misalignment and non-uniform source intensity, the optimized ring aperture maintains higher reconstruction quality than the other two systems. The application of bilateral filtering further enhances the contrast and uniformity of the reconstructed images, bringing the optimized ring aperture reconstruction closer to the actual source image. [Conclusions] This study proposes a novel scattering coded imaging system with an optimized design aimed at accurately measuring the intensity distribution of the dose field in intense pulsed gamma radiation fields. Through optimization, the system achieves high robustness and accuracy within a compact space, effectively addressing radiation imaging needs in extreme radiation environments. This system provides a new way to realize radiation imaging in extreme radiation environments.