利用大亚湾低本底中微子探测器研究宇宙线相关放射性同位素产额

宇宙线缪子产生的放射性同位素是稀有事例探测实验（中微子探测、双Beta衰变实验、暗物质实验等）的重要本底来源，精确理解宇宙线产生的放射性同位素本底对现在以及未来一定时间内的实验探测都是极重要的一项任务。国外有相关实验在几个特定能量下测量了缪子在液体闪烁体中对不同放射性同位素的产额，但是其结果都显示与理论模型计算有不小的差距。在新的缪子能量下给出独立测量，将填补国内外数据空白。大亚湾反应堆中微子实验的物理目标是高精度测量中微子振荡混合角theta13，是我国第一个地下、大体积、低本底、多站点不同岩石覆盖深度（特有宇宙线平均能量）、正全效运行的高性能液体闪烁体探测器系统，具有极高的缪子探测效率和优良的探测器性能，为我们实现准确测量相应缪子能量下宇宙线放射性同位素产额，提高其产生截面测量精度，提供了得天独厚的特有条件，将对宇宙线放射性同位素问题的理解产生重大促进作用。

Radioactive isotopes produced through cosmic Muon spallation are improtant background for rare event detection, such as neutrino detections, double-beta-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic background is particularly important for this kind of experiments at present and in future to reduce their background uncertainty. There had several previous experiments (CERN SPS NA54, KamLAND, MINOS, Borexino etc.) had measured the production of radioactive isotopes from Muon or its secondary particals in liquid scintillator with several separate Muon energies, while all the measured results are inconsistent in a certain level with the theoretical model calculation. New and standalone measurement for Muon-induced radioactive isotopes with different Muon energies will contribute a lot to the world to help to improve its understanding and next rare event detections. Daya Bay reactor neutrino experiment is designed to measure the neutrino oscillation mixing angle theta13 with high precision, which has the advantages as China first running, large volume, underground, low background, different rock coverage (3 separate Muon energies), very high Muon detecting efficiency and great detector performance, and can serve us as a new experiment to achieve a precise measurement for Muon-induced radioactive isotopes production..Daya Bay experiment has 3 experiment halls: their averaged Muon energy covered 50~60GeV at near sites ,and ~140GeV at the far site. The cross check among 3 sites is another important advantage to the measurement.