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中子源常见事故及处置方案 被引量:1
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作者 李明 李雁 +1 位作者 高博跃 张强 《科技视界》 2017年第8期222-223,共2页
补偿中子测井,是在中子测井的基础上进行图版校正,克服井眼不规则变化影响的一种中子测井方法。它同时记录长短源距探头的计数值,可在裸眼井或套管井中测量地层孔隙度。其中,Baker Hughes公司的补偿中子测井仪(2446XA)在各油田得到广泛... 补偿中子测井,是在中子测井的基础上进行图版校正,克服井眼不规则变化影响的一种中子测井方法。它同时记录长短源距探头的计数值,可在裸眼井或套管井中测量地层孔隙度。其中,Baker Hughes公司的补偿中子测井仪(2446XA)在各油田得到广泛应用,但在测井作业中,也时常出现各种放射源事故,造成人员过量照射,给个人及公司及带来巨大损失。本文就补偿中子仪器及所用放射源(Am-241/Be)展开研究,分析其设计结构及作业中可能遇到的问题,提供了一些解决办法,提高了作业的安全性和时效性。 展开更多
关键词 Baker HUGHES 补偿中子 测井 2446XA am-241/be
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Gamma-ray compton spectrum analysis to enhance medical imaging using wavelet transformation
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作者 Saman Ebrahimi Ali Pazirandeh 《Natural Science》 2011年第11期963-970,共8页
Cs-137 radioactive source with 661.7 keV gamma- ray energy and Am-241 with 59.5 keV gamma-ray energy were used to study the body structure of materials by examining transmitted gamma-ray spectrum using a scintillation... Cs-137 radioactive source with 661.7 keV gamma- ray energy and Am-241 with 59.5 keV gamma-ray energy were used to study the body structure of materials by examining transmitted gamma-ray spectrum using a scintillation detector, NaI(Tl). Due to specific characteristic properties of the medium, the passing Compton broad scattering spectrum contains valuable information. It is possible to mark and to specify the Compton spectrum caused by atomic specifications of Al, Cu, bone, muscle, and lipid as interactive materials. Wavelet transforms and other multi-scale analysis functions have been used for compact signal and image representations in de-noising, compression and feature detection processing problems for about twenty years. Comparing the transmitted spectra through muscle, bone and a tumor-like (fat) and analyzing each spectrum by wavelet analysis, the differences of the medium were shown. This study is devoted to use of wavelet transform for feature extraction associated with gamma spectrum, which corresponds to image pixel, and their classification in comparison with the Haar and Rbio3.1 transforms. 展开更多
关键词 Wavelet HAAR Rbio3.1 COMPTON Scattering MATLAB Al Cu MUSCLE Bone LIPID am-241 CS-137
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