Measurement of ambient neutrons in an underground laboratory at Kamioka Observatory and future plan
Measurement of ambient neutrons in an underground laboratory at Kamioka Observatory and future plan
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神冈天文台地下实验室的环境中子测量和未来计划
DOI：
10.1088/1742-6596/1468/1/012247
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Yoshida Sei
中科院分区：
文献类型：
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作者：
Mizukoshi Keita;Taishaku Ryosuke;Hosokawa Keishi;Kobayashi Kazuyoshi;Miuchi Kentaro;Naka Tatsuhiro;Takeda Atsushi;Tanaka Masashi;Wada Yoshiki;Yorita Kohei;Yoshida Sei
环境中子是寻找罕见事件的地下实验最重要的背景之一。用3He正比计数器测量了神冈天文台地下实验室的环境中子通量。由于探测器的响应在很大程度上取决于光谱形状，因此通过蒙特卡罗模拟估计了从岩石传输到实验室的中子的能谱。热中子通量与总中子通量之比取决于岩石的热化效率。因此，使用不加主持人的计数率与有主持人的计数率之比来确定该参数。从而得到了由实验结果确定的参数的模拟所预测的最可能的中子谱。这一结果表明了一种有趣的光谱形状，这在以前的研究中没有显示出来。总的环境中子通量是
Ambient neutrons are one of the most serious backgrounds for underground experiments in search of rare events. The ambient neutron flux in an underground laboratory of Kamioka Observatory was measured using a 3 He proportional counter with various moderator setups. Since the detector response largely depends on the spectral shape, the energy spectra of the neutrons transported from the rock to the laboratory were estimated by Monte-Carlo simulations. The ratio of the thermal neutron flux to the total neutron flux was found to depend on the thermalizing efficiency of the rock. Thus, the ratio of the count rate without a moderator to that with a moderator was used to determine this parameter. Consequently, the most-likely neutron spectrum predicted by the simulations for the parameters determined by the experimental results was obtained. The result suggests an interesting spectral shape, which has not been indicated in previous studies. The total ambient neutron flux is