Design And Development Of μSR Spectrometer Based On Experimental Muon Source At China Spallation Neutron Source

μSR(Muon Spin Rotation/Relaxation/Resonance)technology is widely used in the research of magnetic materials,superconducting materials,semiconductor materials,particle transport,etc.Muon based on accelerator has many advantages,such as high polarizability,extremely sensitive to magnetism,and suitable for various types of samples,and has received more and more attention and applications in recent years.The μSR spectrometer is the terminal of the μSR technology application,and the development of the μSR spectrometer technology is the key point of the μSR experiment.China Spallation Neutron Source will build the first μ beam in China and theμSR spectrometer should be designed to fit the μ beam.The main work of this thesis is to design and develop the first-generation μSR spectrometer of China,which is optimal under the current design parameters of China Spallation Neutron Source,and to design the second-generation ultra-high array μSR(UHAM)spectrometer,which lays the foundation for the design and development of the future μSR spectrometer in China.In this thesis,a 256-channel μSR spectrometer is simulated and designed,and a 128-channel μSR spectrometer prototype is developed successfully.According to the design parameters of the Experimental Muon Source at China Spallation Neutron Source,the design of the 256-channel μSR spectrometer has been completed.All indicators meet the requirements,and its asymmetry factor reaches international leading level.It is determined that the spectrometer will be developed in two stages,and the prototype of the 128-channel μSR spectrometer has been developed as the first stage.The assembly and test of the single-channel detector and the test of the electronic system are completed,and it is confirmed that the performance of the single-channel detector meets the requirements.The construction of the 128-channel μSR spectrometer prototype has been completed,and the acceptance test has been successfully passed.All indicators are better than the project requirements,and some indicators have certain international competitiveness.In this thesis,the influence of detector geometry on the performance of μSR spectrometer is simulated and analyzed.The influence of the geometric structure of a single detector on the performance of the μSR spectrometer is studied,and the conclusion that the cuboid detector is better than the frustum detector is obtained.The concept of feature length and angle discrimination capability was proposed,and the use of 50 mm long cuboid detectors was determined.The influence of the geometric structure of the single detector ring on the performance of the μSR spectrometer is studied,and the influence of the multiple counts is analyzed.It is concluded that Pointing Arrangement is better than Parallel Arrangement.In this thesis,an ultra-high array μSR spectrometer is simulated and designed.Six different μSR spectrometer structures are proposed:cylindrical structure at Parallel Arrangement,cylindrical structure at Pointing Arrangement,conical structure at Parallel Arrangement,conical structure at Pointing Arrangement,spherical structure at Parallel Arrangement,spherical structure at Pointing Arrangement.The asymmetry factor,count rate,percentage of multiple counts,and figure of merit of different structures are studied in the zero-field and longitudinal-field environments.Based on the general figure of merit,the concept of quality is proposed to evaluate the performance of the μSR spectrometer.Finally,it is concluded that the conical structure at Pointing Arrangement with 50 mm long cuboid detectors is the optimal structure.