论文标题
在中国地下实验室的宇宙背景研究
Cosmogenic background study for a 100Mo-based bolometric demonstration experiment at China JinPing underground Laboratory
论文作者
论文摘要
我们对基于10公斤的$^{100} $ MO的验证示范实验进行了模拟研究。基于GEANT4 TOOLKIT研究了基于cry库中的模拟宇宙射线数据，研究了$^{100} $ mo-富集锂晶体和检测器系统的铜成分的宇宙源产生。研究了宇宙源性放射性核素的背景能谱，包括$^{56} $ CO，$^{82} $ rb和$^{88} $ y，这对$^{100} $ MO基于$0νββ$实验是有害的。然后，我们评估$^{100} $ MO $0νβ$搜索能量的搜索能量区域（ROI）中的总宇宙背景水平（ROI）。经过一年的地下冷却后，剩余的背景贡献分别为1.8 $ \ times $ 10 $^{ - 6} $ CTS/kg/kg/kev/yr和3.3 $ \ times $ 10 $^{ - 4} $ CTS/kg/kg/kg/kev/kev/yr，分别来自水晶和铜组件。此外，根据中子和质子在CJPL中的模拟光谱计算铜和钼酸锂晶体的地下宇宙激活。发现地下宇宙背景在ROI中可以忽略不计。
We perform simulation study for a 10-kg $^{100}$Mo-based bolometeric demonstration experiment for neutrinoless double-beta decay ($0νββ$) search at China JinPing underground Laboratory (CJPL). Cosmogenic production of radionuclides in $^{100}$Mo-enriched lithium molybdate crystals and copper components of the detector system are studied using Geant4 toolkit based on the simulated cosmic ray data from the CRY library. Background energy spectra of the cosmogenic radionuclides including $^{56}$Co, $^{82}$Rb and $^{88}$Y which are harmful for the $^{100}$Mo-based $0νββ$ experiment are investigated. We then evaluate the total cosmogenic background level in the $^{100}$Mo $0νββ$ search energy region of interest (ROI) for the demonstration experiment. After one year of cooling down underground, the residual background contribution is found to be 1.8$\times$10$^{-6}$ cts/kg/keV/yr and 3.3$\times$10$^{-4}$ cts/kg/keV/yr from crystals and copper components, respectively. Furthermore, underground cosmogenic activation of copper and lithium molybdate crystal is calculated based on the simulation spectra of neutron and proton in CJPL. The underground cosmogenic background is found to be negligible in the ROI.
