Study On Comparison Of Luminescence Performance Of GAGG:Ce Ceramic And Crystal Luminescence And α/γ Pulse Shape Discrimination For A YAG:Ce/CsI:Tl Phoswich Detector

Scintillation detectors are the most widely used nuclear radiation detectors in the world today,and their quality is closely related to the choice of scintillator materials.Inorganic scintillation crystals are used in many fields of nuclear technology and physics due to their scintillation properties after interaction with radiation fields.This material is coupled to a photomultiplier tube,which converts the energy of the incident radiation into light through ray-matter interaction,which is channeled through the reflective layer into a photoelectric conversion device that converts the light pulse into an electrical signal,which is amplified to produce a measurable voltage pulse,and this pulse is transmitted to a computer terminal through a multi-channel analyzer.In the last few decades,incredible developments have been made in crystalline scintillators.In recent years,the development of cerium-doped gadolinium aluminum gallium garnet oxide scintillator Gd₃（Al,Ga）₅O₁₂:Ce（GAGG:Ce）materials with high effective atomic number,high optical output,fast attenuation and high energy resolution,which are ideal for new nuclear radiation detectors,has attracted many researchers.Recently,GAGG:Ce materials,produced in ceramic form,have become a popular research topic due to their excellent structural and physical properties,and the optical yield of GAGG:Ce ceramics is as high as 70,000 ph/Me V,which is much higher than that of the corresponding crystalline materials,and the chemical stability and resistance to irradiation damage of scintillation ceramics are better than those of scintillation crystals.Compared to GAGG:Ce ceramics,yttrium aluminum garnet Y₃Al₅O₁₂:Ce（YAG:Ce）scintillation ceramics are a relatively simple material to synthesize with dense,efficient and fast response,which can effectively implementα/γparticle species identification at low radioactivity levels.The rise time discrimination method allows us to easily implement the classification of events,while the processing of mixed field pulses allows for off-line analysis to achieve the actual particle identification effect.In this work,we analyze and measure the types of particles incident into the detector inα/γhybrid radiation field measurements from the basic knowledge of scintillator material luminescence principles,scintillation detector composition and assembly,and pulse shape screening,aiming to provide valuable information for furtherα/γdiscrimination and measurement studies.Our preliminary study is a comparison of the luminescence properties of GAGG:Ce ceramics and crystals,with the experimental aim of demonstrating the feasibility of scintillation ceramic discrimination of radiation.On this basis,we tested theα/γ-ray discrimination capability of GAGG:Ce,tested the assembly of scintillation detectors,and performed pulse processing and energy spectrum analysis.We compared the pulse height spectra ofγ-source ¹³⁷Cs andα-source ²³⁹Pu to obtain theα/γratio per unit energy deposited.Finally,the following conclusions are drawn:（1）the light output of GAGG:Ce scintillation ceramics is higher than that of the corresponding crystal materials;（2）GAGG:Ce scintillation ceramics have a certain pulse shape discrimination ability with anα/γratio of0.207;（3）considering that theα/γof GAGG:Ce crystal materials have been reported in the literature to reach 0.67,the pulse shape discrimination ability of GAGG:Ce scintillation ceramics discrimination ability has much room for improvement.Based on the development potential of these scintillation ceramics for radiation detection,we synthesized a YAG:Ce scintillation ceramic using a high-temperature sintering method to further investigate the application of YAG:Ce ceramics in particle-discriminating phoswich detectors.In the next work,we proposed to design and assemble a YAG:Ce/Cs I:Tl phoswich detector for the determination of low radioactivity levels by coupling a Cs I:Tl crystal and a YAG:Ce scintillation ceramic one after the other on the same photomultiplier tube.Using this phoswich device,signals from different scintillators are distinguished with the help of pulse shape phoswich techniques to experiment theαandγpulse shape phoswich effects and thus achieve the goal of particle identification.In theα/γmixed field,the rise time phoswich method can effectively achieve the role of particle identification.In addition,the quality factor of the phoswich detector is improved compared to that of the scintillation detector.The high reliability,simplicity and low cost of the combined ceramic and crystal design make YAG:Ce ceramics extremely promising for particle species phoswich.