共查询到19条相似文献,搜索用时 58 毫秒
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采用同位素稀释法由10Be标准参考物质SRM4325制备系列 10Be/9Be标准样品,在北京HI-13串列加速器的AMS系统上对该系列标准(n(10Be)/n(9Be)范围为2.68×10-11~2.38×10-12)进行测量。测量结果显示,n(10Be)/n(9Be)测量值与标称值呈良好线性关系,且归一化后的测量值与标称值吻合。该系列标准可用于北京HI-13串列加速器的AMS系统对地质环境样品中10Be/9Be绝对比值的准确测定。 相似文献
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光电器件门控技术是辐射脉冲选择测量的关键技术之一.本文主要讨论电流型光电倍增管的控制方法,研究了光电子通路门控电路,设计了模拟实验装置,给出了电流型门控倍增管性能的实验测量结果;开关延迟时间300ns,上升时间1200ns,总开关时间1500ns,消光比1000:1. 相似文献
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针对不同评价数据给出的裂变谱中子引起的241Am(n,γ)242Amg,m反应截面存在很大差异的状况,本文提出了一种利用钚材料实验的有关数据推算241Am(n,γ)242Amg,m反应截面的方法,两次实验得到的结果分别为0.506×10-24cm2(4.1%)和0.505×10-24cm2(4.1%)。 相似文献
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大亚湾反应堆中微子实验是一个研究中微子振荡的实验[1],主要目标是利用核反应堆产生的电子反中微子来测定一个具有重大物理意义的参数—中微子混合角θ13。大亚湾中微子实验的目标是将sin22θ13测量到0.01或更高的精度,为实现对大亚湾中微子信号的准确测量,必须要求光电倍增管输出干净脉冲信号到前端电子学(FEE),但在测试实验中,发现光电倍增管输出脉冲含有振铃。针对振铃进行了详尽分析,找到了振铃产生的根源,也确认了电容在高压下的压电效应。 相似文献
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采用T(d,n)~4 He脉冲中子源和中子飞行时间法测量了3种不同尺寸聚乙烯样品在60°方向的泄漏中子飞行时间谱。通过3种模拟模型(点探测器简化模型、点探测器复杂模型和环探测器复杂模型),应用MCNP程序分别模拟得到了泄漏中子飞行时间谱,并与实验数据进行比较。结果显示:对于小体积样品(?13cm×6cm),3种模型的模拟数据和实验结果在n-p散射峰符合均很好;对于大体积样品(30cm×30cm×6cm,40cm×40cm×6cm),采用环探测器复杂模型的计算结果更加接近实验值。该研究工作为将来开展大体积样品基准检验奠定了基础。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(10):771-787
Energy-angle double-differential neutron emission cross sections of lithium isotopes were measured at incident neutron energies of 4.2, 5.4 and 14.2 MeV for 6Li and of 5.4, 6.0 and 14.2 MeV for 7Li using a time-of-flight spectrometer. Care was taken in background subtraction and in data correction for sample-size effects. Detailed comparison of the present results was made with the evaluated data in JENDL-3PR1. A spectrum fitting method was used to extract the 6,7Li(n, n'x)α and (n, 2n) reaction cross sections. Neutrons emitted from the (n, 2n) reactions were well described by the conventional evaporation model. A simple calculation with a final-state Coulomb interaction was effectively applied for the 6,7Li(n, n'x)α reactions. Angle-integrated cross sections of the 7Li(n, n't)α reaction were in good agreement with the JENDL-3PR1 data except the data measured at 6.0MeV. The angular distributions of elastically and inelastically scattered neutrons were successfully analyzed with the coupled-channel method at the incident neutron energy of 14.2 MeV. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):422-427
The neutron energy dependent response of the α-track detector, cellulose nitrate film (Kodak LR-115 type I) in contact with a lithium radiator was calculated. The “mean effective thickness L eff” of the radiator is obtained as a function of the neutron energy and incident angle. The distribution of the etched-through-track density is evaluated from the calculated L eff and compared with the measured results in the fusion blanket assembly. 相似文献
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2H(d,n)3He核反应中子注量的伴随粒子法测量 总被引:1,自引:0,他引:1
^2H(d,n)^3He核反应单能中子源广泛应用于MeV中子的散射和极化实验。采用伴随粒子法测量中子注量,用Si半导体探测器测量^3He粒子,用0.8μm Al箔来屏蔽散射的d束,系统可很好地分辨^3He,d,T和p,可测d^ 束能量到165keV,测量结果与用NE213探测器的结果相比较,一致性好于97%。 相似文献