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Proceedings Paper

Analysis of noise power spectrum of gamma rays camera
Author(s): Hongwei Xie; Faqiang Zhang; Jianhua Zhang; Jinchuan Chen; Dingyang Chen; Linbo Li
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Paper Abstract

Gamma rays camera is widely used in many studies, including the image diagnostics of the radiation sources, flash photography, and nondestructive assessment (NDA), etc. As a major component of the high sensitivity gamma rays camera, the MCP image intensifier is characterized in the intensified image, tunable shutter time and gain. The gamma rays camera is consisting with rays-fluorescence convertor, the optical imaging system, the MCP image intensifier, CCD and other devices. The performance of the gamma rays camera is mainly dependent on such parameters as the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE), etc. All of the parameters are somewhat limited by the noise characteristics of the system. Compared with the standard derivative noise distribution, the NPS, which can reflect the evolution characteristics of the noise of the imaging system with the change of the spatial frequency, could convey more information on the noise distribution in the system. In this paper, theoretical analysis is presented on the major sources of the noise in the gamma rays camera. Based on the analysis, the noise power spectra of the gamma rays camera were calibrated under various radiation dosages respectively with the visible light and gamma rays radiation sources (0.2MeV and 1.25MeV in energy, respectively). As indicated by the experimental results, the noise is majorly induced by the fluctuations of the gain of the MCP image intensifier. And the remarkable noise peak occurs nearby the spatial frequency of about 0.633 Hz/mm. And almost the same phenomena were found with both the 0.2MeV and 1.25MeV radiation energy. Besides, the noise power spectra are in circular symmetrical distribution, whose intensities are rapidly decreased with the increasing spatial frequencies.

Paper Details

Date Published: 3 February 2014
PDF: 9 pages
Proc. SPIE 9016, Image Quality and System Performance XI, 90160S (3 February 2014); doi: 10.1117/12.2035275
Show Author Affiliations
Hongwei Xie, Institute of Nuclear Physics and Chemistry (China)
Faqiang Zhang, Institute of Nuclear Physics and Chemistry (China)
Jianhua Zhang, Institute of Nuclear Physics and Chemistry (China)
Jinchuan Chen, Institute of Nuclear Physics and Chemistry (China)
Dingyang Chen, Institute of Nuclear Physics and Chemistry (China)
Linbo Li, Institute of Nuclear Physics and Chemistry (China)

Published in SPIE Proceedings Vol. 9016:
Image Quality and System Performance XI
Sophie Triantaphillidou; Mohamed-Chaker Larabi, Editor(s)

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