Study On Scintillation Performance Of Scintillation Materials(LYSO,GAGG) For Particle Detection

Inorganic scintillator detectors are currently widely used in medical diagnosis,safety inspection,high-energy physics and other fields.Inorganic scintillators have excellent scintillation properties such as high density,high light yield and high transmittance,as well as stable physical and chemical properties.Coupled with photodetectors,they become one of the core detectors in high-energy physics nuclear physics experiments.In recent years,Ce³⁺doped yttrium lutetium silicate(LYSO:Ce)and gadolinium gallium aluminum garnet(GAGG:Ce)have attracted widespread attention in the field of nuclear detection.LYSO:Ce has a high light yield of up to 30000 ph/Me V,its decay time is very fast(<40 ns),and the density is very large(7.1g/cm³),which is very suitable for popular nuclear medical equipment TOF-PET and the field of nuclear radiation detection.The absolute light yield of GAGG:Ce scintillator is very high,up to 60000 ph/Me V,energy resolution can reach 5%@662 ke V,and its decay time is fast,without hygroscopicity and self-radiation problems.In addition,GAGG:Ce contains Gd elements,and its thermal neutron capture cross-section is as high as 255000 b,which is the largest thermal neutron reaction cross-section among known nuclides.This crystal is very suitable for making calorimeters and thermal neutron detectors.In order to respond to the scintillator screening requirements of large scientific projects such as the development of large-scale collider experimental detectors,space load calorimeters,and new medical imaging equipment TOF-PET,our laboratory conducts research on the scintillation performance(emission spectrum,light output,energy resolution,decay time,afterglow and coincidence time resolution,etc.)of scintillators.A complete set of inorganic scintillator performance test programs is designed.The highly researched LYSO:Ce was tested,and compared with the results in the literature to test this program,and successfully applied to the popular scintillator GAGG:Ce performance research,and achieved good test results.In the designed test plan,the emission spectra of the scintillators under different excitation sources were compared to simplify the experimental device.Improve the test accuracy of the afterglow time of the scintillator.The scintillator energy resolution,light output,and time-resolved test conditions are optimized.Optimize the energy resolution,light output and coincidence time resolution test conditions of the scintillator.The results show that the energy resolution of LYSO:Ce can reach 8.05%@662ke V,its light output is 27029 ph/Me V,and after surface roughening,it can reach 36408ph/Me V.Its decay time is 38.7 ns.When coupled with a fast photomultiplier tube,the coincidence time resolution can reach 95.9 ps.The energy resolution of ceramic and single crystal GAGG:Ce are 5.40%and7.09%@662 ke V,respectively.The neutron test experiment was conducted by coupling single crystal GAGG:Ce and silicon photomultiplier tube,and the internal conversion electrons of 33 ke V and77 ke V generated by the interaction between GAGG:Ce and thermal neutrons can be clearly observed in the energy spectrum.When GAGG:Ce composite crystal is used for neutron gamma discrimination,the FOM can reach 2.40,which realizes the obvious discrimination of neutron gamma.