Spin polarization and production rate studies of surface muons in a novel solenoid capture system based on CSNS  

作　　者：Ran Xiao Yan-Fen Liu Xiao-Jie Ni Zi-Wen Pan Bang-Jiao Ye 

机构地区：[1]State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei 230026, China [2]Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China [3]Institute of High Energy Physics, Chinese Academy ofSciences, Beijing 100049, China

出　　处：《Nuclear Science and Techniques》2017年第8期61-68,共8页核技术（英文）

基　　金：supported by the National Natural Science Foundation of China(No.11527811)

摘　　要：A novel surface muon capture system with a large acceptance was proposed based on the China spallation neutron source(CSNS).This system was designed using a superconducting solenoid where a long graphite target was put inside it.Firstly,the spin polarization evolution was studied in a constant uniform magnetic field.As the magnetic field can interact with the spin of the surface muon,both the spin polarization and production rate of the surface muons collected by the new capture system were calculated by the G4beamline.Simulation results showed that the surface muons could still keep a high spin polarization([90%)with different magnetic fields(0–10 T),and the larger magnetic field is,the more surface muons can be captured.Finally,the proton phase space,Courant–Snyder parameters,and intensities of surface muons of different beam fractions were given with magnetic fields of 0 and 5T.The solenoid capture system can focus proton and surface muon beams and collect p?and l?particles.It can also provide an intense energetic positron source.A novel surface muon capture system with a large acceptance was proposed based on the China spal- lation neutron source （CSNS）. This system was designed using a superconducting solenoid where a long graphite target was put inside it. Firstly, the spin polarization evo- lution was studied in a constant uniform magnetic field. As the magnetic field can interact with the spin of the surface muon, both the spin polarization and production rate of the surface muons collected by the new capture system were calculated by the G4beamline. Simulation results showed that the surface muons could still keep a high spin polar- ization （〉90%） with different magnetic fields （0-10 T）, and the larger magnetic field is, the more surface muons can be captured. Finally, the proton phase space, Courant-Snyder parameters, and intensities of surface muons of different beam fractions were given with magnetic fields of 0 and 5 T. The solenoid capture system can focus proton andsurface muon beams and collect π± and μ± particles. It can also provide an intense energetic positron source.

关 键 词：自旋极化率 采集系统 Μ介子 表面 电磁 生产 均匀磁场 自旋相互作用 

分 类 号：O571.53[理学—粒子物理与原子核物理]