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补偿中子测井受到环境温度的影响,利用数值模拟计算来进行修正,但目前的理论计算程序MCNP缺乏水的精细温度相关的热中子散射数据库。为了解决蒙特卡罗模拟热中子散射S(α,β)模型只能求解特定温度条件下中子输运问题的局限性,基于热中子散射的S(α,β)原理,采用内插法得到不同温度下水的频谱分布、振动;在最新的ENDFB-VII.1数据库上,利用NJOY99程序制作了ACE格式的轻水热中子散射截面数据库。利用系列次临界基准题对数据的准确性进行了验证,不同数据库之间的计算结果及基准题的结果符合得很好。自制的数据应用于测井仪器中的温度效应修正,取得了较好的效果。 相似文献
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在中子检测爆炸物的研究中,利用14 MeV中子与原子序数大于5的原子核相互作用可产生特征射线的特性,采用伴随粒子法结合D-T中子飞行时间技术,使用尺寸为12.5 cm20 cm的大体积NaI(Tl)探测器,对爆炸物所含元素C,N,O以及一些模拟炸药样品进行了瞬发谱测量。获得了几种典型样品的特征谱,并对其进行了分析。实验结果与欧盟同期结果进行了比较,表明本实验研究达到了目前国际同类实验的水平,可以为中子检测爆炸物识别技术提供实验支持。 相似文献
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A VME-based experiment system for n-y discrimination using the charge comparison method was established.A data acquisition program for controlling the programmable modules and processing data online via VME64X bus was developed through the use of Lab VIEW.The two-dimensional(2D) scatter plots of the charge in the slow component vs.the total charge from ~(241)Am-Be and ~(252)Cf neutron sources are presented.The 2D scatter plots of the energy vs.the ratio of the charge in the slow component to the total charge of the pulses are also presented.The quality of n-γ discrimination was checked by the figure-of-merit,and the results showed good performance of n-γ discrimination at the low energy range.Neutrons and γ-rays were separated above 50 keVee(electron-equivalent energy).The quality of n-γ discrimination has been improved compared with others' results at five energies(150,250,350,450,550 keVee). 相似文献
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瞬发裂变中子谱(prompt fission neutron spectrum,PFNS)是用于核实验诊断过程中十分重要的参数数据,传统的测量主锕系核素(U,Pu)PFNS的技术手段是采用裂变室,利用裂变碎片标识裂变中子,通过中子飞行时间技术获得裂变中子谱.目前出现了一种新的用于PFNS测量的技术,其原理是基于如下的物理事实:在一次裂变过程中,释放中子的同时伴随着释放7–8个γ射线光子,而非弹性散射效应产生的γ射线光子只有1–2个.据此,可以通过裂变γ射线的多重性将裂变中子和其他杂散中子甄选出来,达到测量PFNS的目的.本文建立了基于裂变γ标识技术的PFNS测量实验系统.利用该系统对252Cf中子源的PFNS进行了实验测量,测量结果与传统的裂变碎片标识法及ENDF/B-VⅡ数据库的标准谱进行了比较,对新方法的裂变标识率以及实验不确定度也一并进行了分析. 相似文献
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A fusion-fission hybrid conceptual reactor is established. It consists of a DT neutron source and a spherical shell of depleted uranium and hydrogen lithium. The tritium production rate (TPR) distribution in the conceptual reactor was measured by DT neutrons using two sets of lithium glass detectors with different thicknesses in the hole in the vertical direction with respect to the D~+ beam of the Cockcroft-Walton neutron generator in direct current mode. The measured TPR distribution is compared with the calculated results obtained by the threedimensional Monte Carlo code MCNP5 and the ENDF/B-Ⅵ data file. The discrepancy between the measured and calculated values can be attributed to the neutron data library of the hydrogen lithium lack S (α,β) thermal scattering model, so we show that a special database of low-energy and thermal neutrons should be established in the physics design of fusion-fission hybrid reactors. 相似文献
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