香港仔隧道實驗室宇宙射線感應中子之研究

Abstract

物理學家計劃在大亞灣興建一個實驗室以量測微中子最後的混合角?13。由於微中子不容易被量測到的特性，我們必須要仔細地研究其周遭的背景以降低背景在實驗方面所造成的誤差。香港仔隧道實驗室座落在香港島上鄰近大亞灣，岩石結構與大亞灣附近的山相似，所以非常適合來研究背景。本論文主要的研究宇宙射線所造成的中子背景，我們利用模擬軟體去估計宇宙射線感應產生的中子流量並加以公式化，利用得到的公式估計香港仔隧道實驗室所得到中子流量，並比較不同模擬軟體間的差異。進一步，我們模擬香港仔隧道真實環境。在香港載隧道實驗取前，對宇宙射線感應的中子流量，以上的結果可以給我們一個合理的預測。

Physicists prepare to measure the last unknown mixing angle $\theta_{13}$ of neutrino in Daya Bay Reactor Neutrino Experiment. Due to the difficult detection of neutrinos, it is necessary to study backgrounds carefully to reduce errors coming from the backgrounds. The Aberdeen Tunnel Laboratory, which is located near Daya Bay and have similar rock compositions as the mountains around Daya Bay,have the advantage to study backgrounds. In this thesis, we mainly focus on the cosmic moun-induced neutron background. We compare the the neutron production rate between three simulation tool kits, FLUKA 2006.3, FLUKA 1999, and Geant4, and obtain a parameterizaion fomula using FLUKA 2006.3. The neutron yield in Aberdeen Tunnel Lab can be estimated via the parameterization fomula. Futhermore, we ha estimate the neutron yield by cosmic muons by relastic simulation in Aberdeen Tunnel Lab. These two results give us a resonable prediction of the Aberdeen Tunnel Experiment.