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Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction

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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： Ding-Han Zhu Xiong Zhang Xiao-Qiang Li Peng Li Yan-Bin Wang Shuang Zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays scattering correction Analytical method Monte Carlo method

Study on scattering correction in fast neutron tomography at NECTAR facility

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 244-250页

作者： LIU ShuQuan BCHERL Thomas ZOU YuBin WANG Sheng LU YuanRong GUO ZhiYu State Key Lab of Nuclear Physics and Technology & School of Physics Peking University Technische Universit t München ZTWB Radiochemie München RCMWalther-Meissner-Str. 3Garching 85748Germany

Fast neutron tomography has been established as an inspection and detection tool at the NECTAR facility at the FRM-II reac- tor. Scattered neutrons from the object become a major disturbance and bring in artifacts and deviations in reconstruction re- suits, especially for hydrogenous material object. In this article, an iterative scattering correction method for fast neutron to- mography was proposed. In each loop of iteration the scattering component of the projections will be simulated by Mon- te-Carlo program MCNPX based on the previous reconstruction result and then it will be subtracted from original projections. The differences between scattering components at different perspectives were quantitatively evaluated and an average scatter- ing component image was used for all projections finally. Smooth and uniform slices with more clear edges were obtained and the new reconstructed attenuation coefficients are quite close to the real one compared to the results without scattering correc- tion, in which case the relative error of the reconstructed attenuation coefficients is about 10%-30%.

关键词： fast neutron scattering correction neutron tomography NECTAR

Improvement of scattering correction for in situ coastal and inland water absorption measurement using exponential fitting approach

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Journal of Oceanology and Limnology 2018年第4期36卷 1198-1215页

作者： YE Huping LI Junsheng ZHU Jianhua SHEN Qian LI Tongji ZHANG Fangfang YUE Huanyin ZHANG Bing LIAO Xiaohan Institute of Remote Sensing and Digital Earth Chinese Academy of SciencesBeijing 100094China University of Chinese Academy of Sciences Beijing 100049China National Ocean Technology Center Tianjin 300112China Sino-Afriea Joint Research Center Chinese Academy of SciencesWuhan 430074China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

The absorption coefficient of water is an important bio-optical parameter for water optics and water color remote sensing. However, scattering correction is essential to obtain accurate absorption coefficient values in situ using the nine-wavelength absorption and attenuation meter AC9. Establishing the correction always fails in Case 2 water when the correction assumes zero absorption in the near-infrared(NIR) region and underestimates the absorption coefficient in the red region, which affect processes such as semi-analytical remote sensing inversion. In this study, the scattering contribution was evaluated by an exponential fitting approach using AC9 measurements at seven wavelengths(412, 440, 488, 510, 532, 555, and 715 nm) and by applying scattering correction. The correction was applied to representative in situ data of moderately turbid coastal water, highly turbid coastal water, eutrophic inland water, and turbid inland water. The results suggest that the absorption levels in the red and NIR regions are significantly higher than those obtained using standard scattering error correction procedures. Knowledge of the deviation between this method and the commonly used scattering correction methods will facilitate the evaluation of the effect on satellite remote sensing of water constituents and general optical research using different scatteringcorrection methods.

关键词： absorption coefficient scattering correction AC9/ACS exponential fitting method