膝区宇宙线广延大气簇射次级成分的特征  

Properties of secondary components in extensive air shower of cosmic rays in knee energy region

作　　者：张丰 刘虎 祝凤荣[1] Zhang Feng;Liu Hu;Zhu Feng-Rong(School of Physical Science and Technology,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]西南交通大学物理科学与技术学院,成都611756

出　　处：《物理学报》2022年第24期466-479,共14页Acta Physica Sinica

基　　金：四川省科技厅项目(批准号:2021YFSY0031,2020YFSY0016);国家重点研发计划(批准号:2018YFA0404201);国家自然科学基金(批准号:12205244,12147208)资助的课题。

摘　　要：膝区反映了银河系宇宙射线源加速粒子能力的极限或银河系对宇宙线束缚能力的极限,分成分能谱的测量是理解膝区物理的重要手段,而宇宙线的成分鉴别和能量重建精度是分成分能谱测量的基础.本文通过CORSIKA软件模拟了不同原初成分的膝区宇宙线的广延大气簇射,对不同次级成分(包括正负电子、伽马射线、缪子、中子和切伦科夫光子)的宇宙线能量重建精度和鉴别能力进行了研究.结果表明:在膝区能段使用次级粒子中的电磁粒子(电子、伽马射线和切伦科夫光)进行能量重建精度较好,其中对于质子,能量重建精度约为10%—19%;对于铁核,能量重建精度约为4%—8%.对于原初宇宙线的鉴别能力,缪子粒子数密度在低能段(约100 TeV)和高能段(约10 PeV)的鉴别能力均最好,在低能段正负电子和伽马射线横向分布形状的年龄参数的鉴别能力较好,在高能段中子的粒子数密度的鉴别能力较好.本文还对使用EPOS-LHC和QGSJet-Ⅱ-04强相互作用模型模拟的不同次级粒子成分的横向分布差异进行了研究.结果表明正负电子、伽马射线和切伦科夫光在距簇射轴垂直距离大于20 m的区域内,差异在5%以内,缪子的粒子数在距簇射轴垂直距离大于100 m的区域内,差异在5%以内,而中子成分的粒子数更依赖于强相互作用模型,两种强相互作用模型的差异大于10%.该研究可为地面膝区能段宇宙线实验的能量重建和成分鉴别时次级成分的选取以及探测器类型的选取提供参考.The“knee”of cosmic ray spectra reflects the maximum energy accelerated by galactic cosmic ray sources or the limit to the ability of galaxy to bind cosmic rays.The measuring of individual energy spectra is a crucial tool to ascertain the origin of the knee.However,the measuring of energy and the identifying of primary nuclei are the foundation of measuring the energy spectra of individual components.The Extensive Air Shower of cosmic rays in the knee energy region is simulated via CORSIKA software.The energy resolution for different secondary components(include electron,gamma,muon,neutron and Cherenkov light)and primary nuclei identification capability are studied.The energy reconstruction by using electromagnetic particles(electron,gamma and Cherenkov light)in the energy around“knee”is better than by using other secondary particles.The resolution is 10%–19%for proton,and 4%–8%for iron.For the case of primary nuclei identification capability,the discriminability of density of muons is best both at low(~100 TeV)and high(~10 PeV)energy,the discriminability of the shape of lateral distribution of electron and gamma-rays are good at low energy and the discriminability of density of neutrons is good at high energy.The differences between the lateral distributions of secondary particles simulated by EPOS-LHC and QGSJet-Ⅱ-04 hadronic model are studied.For electron,gamma and Cherenkov light,the differences of the number of particles are within 5%;for muon,when the perpendicular distance from the shower axis is greater than 100 m,the difference of the muon number is within 5%;for neutron,the difference in neutron number between the two models is larger than 10%.The results in this work can provide important information for selecting the secondary components and detector type during energy reconstruction and identifying the primary nuclei of cosmic rays in the knee region.

关 键 词：广延大气簇射 宇宙线 粒子鉴别 能量重建 

分 类 号：P172.4[天文地球—天文学]