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用被动探测的方法,在尽量短的时间内,准确探测密封在容器罐中的钚材料的特征属性,譬如同位素丰度、钚材料的年龄等,是核材料控制的一个重要技术手段。用高分辨γ谱仪在钚材料密封容器罐外一定距离处进行一定时间的测量,可以获得高分辨的γ射线能谱,如何从这些能谱中求解出钚材料同位素丰度和年龄是主要的研究内容。相对效率法利用测量对象的能谱信息作自身效率刻度,而不需要使用标准源来进行探测效率的刻度;在相对效率曲线上,绝对探测效率之比等于相对探测效率之比。因此,只要从能谱中求解出任意两个核素不同能量的特征峰峰面积,就可以求出这两种核素的核子比。 相似文献
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以γ射线的能量与强度所构成的二维平面为论域,提出了关于γ射线能谱的二维模糊集合的概念,建立了γ射线能谱二维模糊集合隶属函数.提出和介绍了γ射线能谱指纹模糊识别的基本原理与方法.通过对γ能谱数据的归一化处理,实现了γ射线能谱指纹的类型识别和个体识别.通过引入识别增强因子,获得了较高的识别置信度.对模拟放射性物质的γ射线能谱指纹进行了识别研究,探讨了系统统计涨落以及探测距离变化对识别隶属度的影响.研究表明,γ射线能谱指纹模糊识别方法具有较强的类型识别能力和个体识别能力,可应用于核安全保障等领域.
关键词:
γ能谱指纹
模糊识别
核材料 相似文献
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《物理学报》2020,(11)
蒙特卡罗方法(MC)是模拟核探测问题的理想方法,用中子照射客体,中子诱发产生非弹γ和俘获γ,通过特征γ射线能谱和时间谱分析,确定客体核素组成和重量百分比.本文基于非弹γ和俘获γ时间门测量技术,给出了脉冲源发射下探测器响应计数公式.在中子与核作用产生次级光子方面,采用期望值估计(expect value estimator,EVE)产光.为了避免大量小权光子模拟带来的计算存储量增加,设计了EVE产光与直接估计(direct estimator,DE)产光耦合.仅增加少量计算时间,便实现了特征γ射线解谱.数值模拟在自主MC软件JMCT上开展,计算结果初步验证了方法的正确有效性. 相似文献
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建立了一套基于局域网的核弹头核查系统.系统的硬件组成为:一台网络服务器、两台个人计算机和一台便携式高纯锗γ谱仪.系统的软件(能谱遮盖软件)包括核查方软件、被核查方软件两个模块,它们都采用交互式人机对话,通过局域网进行通讯.核查中,探测器所采集的高分辨γ射线能谱需要经过被核查方软件的防泄密处理后,才能以遮盖能谱或文字显示方式发送给核查方终端.能谱遮盖的原则是,对核查方要求核查的能段,核查方软件必须提供真实、客观的显示;而对其他能段,可根据被核查方对“敏感信息”的认识,作适当的遮盖处理.文字显示方式则是直截了当地回答核查对象是“铀弹”、“钚弹”或“非核弹”.利用能谱遮盖软件对模拟核弹头进行了类型识别和能谱遮盖实验.实验结果表明,所建立的基于局域网的核弹头核查系统具有识别模拟核弹头类型和在核查中保护敏感信息泄漏的功能,特别值得指出的是,核查结果文字显示方式具有较好的防泄密功能,有助于提高核查可信度.实验同时也暴露了该系统的一些不足点,如系统组件过多,集成度不够;被核查方软件的人机交互对话和核查结果的能谱遮盖显示方式可能降低核查的可信度等等
关键词:
核弹头核查
γ射线能谱
能谱遮盖 相似文献
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针对放射性物质异常泄漏、防范核材料的非法转移和任意携带,提出一种基于单探头中子/伽马甄别能谱仪系统,实现敏感控制区中特殊核材料和放射性物质的监测。围绕核信号获取与数字化采集、辐射射线粒子甄别与能谱分析,开展基于FPGA与EJ299-33A的核数据采集电路设计、核信号处理算法设计和Matlab中子/伽马鉴别与能谱离线分析方法等关键技术研究。设计上位机软件实时处理辐射能谱数据,为正确做出应急预案提供数据参考。利用新型探测器和分型频谱数学模型在FPGA内部实现射线种类甄别,有效地解决了采用传统老式探测器和模拟电路的方法鉴别困难的问题,验证了分型频谱法在核信号处理上具有一定的可行性。开发完成集放射性种类判定、核素识别于一体的多功能集成中子/伽马探测器,在中子/伽马的混合辐射场中,既能实现射线甄别又能测量能谱,解决在复杂放射性环境中对不同射线种类的能谱分析和核素识别问题。 相似文献
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密封容器中钚材料同位素丰度和年龄的测量 总被引:1,自引:0,他引:1
根据相对效率法的原理,利用PC/FRAM分析软件,开展了用高分辨γ谱仪测量密封容器中钚材料的同位素丰度和年龄的实验研究.研究结果表明,同位素丰度和年龄的分析精度随能谱测量精度的提高而提高,如果能谱的测量精度不够,通过PC/FRAM分析得出的钚材料的同位素丰度和年龄有偏低的可能.因此,在能谱测量过程中,建议通过监测某个特征峰的峰面积计数来判定239Pu丰度和年龄的测量精度是否已满足测量要求.Based on the concept of relative detection efficiency, some experiments have been conducted to measure the isotopic abundance and the age of the plutonium material in a sealed container by a high-resolution γ-ray spectrometer. The PC/FRAM software analyzes the spectra. The study shows that the analysis precision of the isotopic abundance and the age will rise as the spectral measurement precision increases, and that If the spectral measurement precision is not enough, the analyzed results by the PC/FRAM software might be lower. Hence, the study suggests that a spectral peak is monitored to show lights on the spectral measurement precision during the process of spectrum acquirement. 相似文献
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A. M. Galper S. I. Suchkov N. P. Topchiev I. V. Arkhangelskaja A. I. Arkhangelskiy A. V. Bakaldin Yu. V. Gusakov O. D. Dalkarov A. E. Egorov V. G. Zverev V. V. Kadilin A. A. Leonov P. Yu. Naumov M. F. Runtso M. D. Kheymits Yu. T. Yurkin 《Physics of Atomic Nuclei》2017,80(6):1141-1145
The GAMMA-400 γ-ray telescope installed at the Russian space observatory is intended for precision measurements in the energy range of 20 MeV–1000 GeV of γ-ray emission (with the angular and energy resolutions several times better than that of current γ-ray telescopes) from discrete sources; measurement of the energy spectra of Galactic and extragalactic diffuse γ-ray emission; studies of γ-ray emission from the active Sun; and measurements of fluxes of γ-ray emission and electron–positron cosmicray component, which are probably associated with the annihilation or decay of dark-matter particles. 相似文献
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K. M. Belotsky A. M. Galper B. I. Luchkov 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(7):915-917
A statistically significant correlation between the position of unidentified discrete γ-ray sources with star formation regions in the Galaxy has been obtained. The fraction of unidentified discrete γ-ray sources coincident with star formation regions was found to be 47 ± 8%. The coincident γ-ray sources have on average more rigid spectra and higher fluxes in comparison with other unidentified discrete γ-ray sources. A possible mechanism of γ radiation from star formation regions is the annihilation of particles of the dark matter concentrated in the star formation regions. 相似文献
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H. Göktürk B. Ekström E. Lund B. Fogelberg 《Zeitschrift für Physik A Hadrons and Nuclei》1986,324(1):117-118
The half lives and the γ-ray branching ratios of neutron rich Cd and In isotopes have been investigated by simultaneous measurements of β- and γ-ray spectra. The results presented contain information on 21 different β-decaying isotopes or isomers of Cd and In in the mass region A=123–129. Four previously unknown or little known isotopes of Cd are reliably characterized for the first time. 相似文献
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G. Landaud A. Baldit J. Castor A. Devaux G. Roche C. Le Brun M. Louvel J. Yonnet 《Nuclear Physics A》1982,384(3):323-344
A p-γ coincidence experiment has been performed with 400 MeV protons on medium nuclei. The angular and momentum analysis of the scattered protons demonstrates a nucleon primary quasi-free process. No indication of knockout reactions on clusters has been seen. The residual nuclei which have been identified from γ-ray spectra are mainly produced by evaporation processes. Intranuclear cascades followed by evaporation are sufficient to describe the multinucleon removal but residual nuclei near the target nucleus are sensitive to the nuclear structure. 相似文献
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为了测定聚变-裂变反应堆模型钍包层中的钍俘获率以及钍-铀转化率, 探索了一种新的钍活化离线γ测量法. 利用测量232Th俘获反应产物233Th衰变链中233Pa衰变放出的311.98 keV 特征γ射线, 来反推计算并最终确定232Th(n,γ)233Th的反应率, 测试实验中不确定度约6% (233Th/232Th量级为10-17情况下). 详细介绍了此方法的背景和原理方法, 并进行简单的校验实验, 证明其能够较好地得到模拟装置中的俘获率. 与瞬发γ测量法以及质谱分析法进行对比, 本方法更适合用于聚变-裂变反应堆模型钍包层中的钍俘获率以及钍-铀转化率测量, 并有望进一步测量其他相关参数. 相似文献
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研制了一种基于微通道板的超快脉冲中子探测器,对其γ射线灵敏度进行了理论和实验研究。建立了探测器的γ射线灵敏度理论计算模型,利用蒙特卡罗方法模拟计算了不同能量γ射线在不同厚度聚乙烯靶中产生的出射电子能谱和出射角度分布,并结合经验公式计算了单个电子在微通道板(MCP)孔道中产生的二次电子产额,最后得到了探测器的γ射线灵敏度,结果表明当聚乙烯靶厚度大于某一值时,γ射线灵敏度基本相同。利用西北核技术研究所的标准γ射线放射源对探测器的γ射线灵敏度进行了实验标定,实验结果与理论计算结果一致。 相似文献
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简要地介绍了中子俘获瞬发γ射线数据及其衰变纲图的评价方法技术、主要程序及其功能、数据评价流程、强度平衡检验,以及对A=1-44的稳定核素和A>190的部分稳定核素的热中子俘获瞬发γ射线数据及其衰变纲图评价的具体应用.The method of prompt γ-ray data evaluation for neutron capture and how to calculate the prompt γ-ray intensities of neutron capture have been briefly presented. The prompt γ-ray data of thermal-neutron capture of some stable nuclei for A=1-44 and A>190 have been evaluated. The ENSDF format has been adopted. The checks of intensity balance and format have been made. The examples are given to illustrate its application. 相似文献
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Two kinds of time differential Mössbauer spectra of57Co-labelled Co(BrO3)2·6H2O were measured at room temperature by delayed coincidence technique, i.e., one was the delayed coincidence between 122 keV γ ray and 14.4 keV γ ray (γ, γ-ray coincidence), and another was the coincidence between 6.3 keV KX ray and 14.4 keV γ ray (X, γ-ray coincidence). The time dependence of chemical states of57Fe-species were observed on γ, γ-ray and X, γ-ray coincidence Mössbauer spectra. The relative area intensities of57Fe(II) observed on the X, γ-ray coincidence spectra were larger than those on the γ, γ-ray coincidence spectra on every time windows. 相似文献