Measurement of Prompt Neutron Decay Constant and Large Subcriticality by the Feynman-α Method
Measurement of Prompt Neutron Decay Constant and Large Subcriticality by the Feynman-α Method
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费曼-α法测量瞬发中子衰变常数和大亚临界度
DOI：
10.13182/nse104-53
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发表时间：
1990
影响因子：
1.2
通讯作者：
K. Kanda
中科院分区：
文献类型：
--
作者：
T. Misawa;S. Shiroya;K. Kanda
在京都大学临界装置上，使用装载高浓缩铀燃料的轻水慢化和反射堆芯进行了费曼-{α}实验。为了提高测量精度，缩短测量时间，提出了一种采用多通道标度器的实验技术。然后，测量了具有不同中子能谱的单芯和耦合芯的{beta}{sub eff}/l值，以证明本技术测量提示中子衰变常数{alpha}的能力。此外，费曼-{α}方法被应用于测量大的亚临界。通过这些实验，发现该方法大大提高了{α}测量的精度，并且一点反应堆近似适用于紧耦合堆芯。还发现，只要选择好中子探测器的位置，这种方法可以测量到大约{-}35 $的亚临界，并且可以将费曼-{α}方法应用于亚临界监测系统。
The Feynman-{alpha} experiments have been carried out using light-water-moderated and -reflected cores loaded with highly enriched uranium fuel at the Kyoto University critical assembly. An experimental technique using a multichannel scaler was developed to improve the accuracy of measurement and to shorten measuring time. Then, the {beta}{sub eff}/l values of single and coupled cores with different neutron spectra were measured to demonstrate the capability of the present technique for measuring the prompt neutron decay constant {alpha}. Moreover, the Feynman-{alpha} method was applied to measuring large subcriticalities. Through these experiments, it is found that the present technique greatly improves the accuracy of {alpha} measurement, and the one-point reactor approximation is applicable to a tightly coupled core. It is also found that the subcriticality down to approximately {minus} 35 $ can be measured by this method if the position of the neutron detector is chosen carefully, and the present Feynman-{alpha} method can be applied to a subcriticality monitoring system.