Feasibility Verification of Single Pixel Imaging Based on Rotating Modulation Collimator for Prompt Gamma Imaging

Abstract

Prompt Gamma Neutron Activation Imaging (PGAI) is an element distribution detection method based on Prompt Gamma Neutron activation analysis (PGNAA). However, detection of the prompt gamma rays in PGAI is limited by the lack of intrinsic spatial resolution in high-energy resolution detectors, such as HPGe. A single-pixel imaging approach is proposed to enhance the spatial resolution capability of a single detector. In this study, a prototype of a single-layer thick collimator based on the principle of rotating modulation collimators (RMC) is proposed. The prototype was encoded by the skew-Hadamard Uniformly Redundant Array (URA). The system matrix was obtained by MCNP5. Monte Carlo simulations and experimental measurements were conducted to investigate the response of the prototype to both single and multiple gamma isotope sources. The MLEM was used for image reconstruction of the gamma distribution. The results show that the reconstructed images can indicate the location of point sources, and the image quality is characterized by SNR and SSIM. For a single gamma point source, the SSIM of the reconstructed image can exceed 0.906. For three Co-60 sources, the SSIM of the reconstructed image is 0.457. Experimental validation with gamma sources showed that the reconstructed images can verify the true positions. These results will guide future studies on measuring the distribution of prompt gamma rays emitted by neutrons.

Keywords: PGAI, rotating modulation collimators, skew-Hadamard URA, reconstruction image