DETECTION OF THE FREE NEUTRINO - CONFIRMATION
DETECTION OF THE FREE NEUTRINO - CONFIRMATION
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DOI：
10.1126/science.124.3212.103
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发表时间：
1956-01-01
期刊：
影响因子：
56.9
通讯作者：
MCGUIRE, AD
中科院分区：
文献类型：
--
作者：
COWAN, CL;REINES, F;MCGUIRE, AD
1953年在汉福德(1)进行的一次实验中，对自由中微子进行了初步的鉴定。在这项工作中，反应v-+p+-：：“FL++NO(1)”，其中来自大型反应堆中裂变碎片衰变的强烈中微子通量入射到一个含许多目标质子的含氢液体闪烁体的探测器上。反应产物被检测为延迟脉冲对；第一个脉冲是由于正电子的减速和湮灭，第二个脉冲是由于捕获溶解在闪烁体中的镉中的慢化中子。为了识别观测到的信号是中微子引起的，使用了两个脉冲的能量、它们的时延频谱、信号速率与反应堆功率的关系以及与预测速率相比的大小。所采用的屏蔽的计算效率，加上用屏蔽罩外部的乳剂进行的中子测量，似乎排除了反应堆中子和伽马辐射是信号的原因。尽管由于反应堆和宇宙辐射都经历了高本底，但人们认为很可能已经对自由中微子进行了鉴定。
A tentative identification of the free neutrino was made in an experiment performed at Hanford (1) in 1953. In that work the reaction v-+ p+--::" fl++ nO(1)\\'as employed wherein the intense neutrino flux from fission-fragment decay in a large reactor was incident on a detector containing many target protons in a hydrogenous liquid scintillator. The reaction products were detected as a delayed pulse pair; the first pulse being due to the slowing down and annihilation of the positron and the second to capture of the moderated neutron in cadmium dissolved in the scintillator. To identify the observed signal as neutrino-induced, the energies of the two pulses, their timedelay spectrum, the dependence of the signal rate on reactor power, and its magnitude as compared with the predicted rate were used. The calculated effectiveness of the shielding employed, together w'ith neutron measurements made with emulsions external to the shield, seemed to rule out reactor neutrons and gamma radiation as the cause of the signal. Although a high background was experienced due to both the reactor and to cosmic radiation, it was felt that an identification of the free neutrino had probably been made.