Investigation of nuclear material using a compact modified uniformly redundant array gamma camera

• Published in: Nuclear engineering and technology Vol. 50; no. 6; pp. 923 - 928
• Main Authors: Lee, Taewoong, Kwak, Sung-Woo, Lee, Wonho
• Format: Journal Article
• Language: Korean
• Published: 2018
• Subjects: Minimum Required Detection Time; UO_2$ Pellet; Modified Uniformly Redundant Array Coded; Aperture; Antimask Subtractive Method
• ISSN: 1738-5733; 2234-358X

We developed a compact gamma camera based on a modified uniformly redundant array coded aperture to investigate the position of a $UO_2$ pellet emitting characteristic X-rays (98.4 keV) and ${\gamma}-rays$ (185.7 keV). Experiments using an only-mask method and an antimask subtractive method were conducted, and the maximum-likelihood expectation maximization algorithm was used for image reconstruction. The images obtained via the antimask subtractive method were compared with those obtained using the only-mask method with regard to the signal-to-noise ratio. The reconstructed images of the antimask subtractive method were superior. The reconstructed images of the characteristic X-rays and the ${\gamma}-rays$ were combined with the obtained image using the optical camera. The combined images showed the precise position of the $UO_2$ pellet. According to the self-absorption ratios of the nuclear material and the minimum number of effective events for image reconstruction, we estimated the minimum detection time depending on the amount of nuclear material.