Experimental And Simulant Studies On The Performance Of A Large Size CsI Detector For High Energy Gamma-rays

Measurement of high-energy gamma is an important experimental method for studying the giant dipole resonance of highly excited nuclei in heavy ion collisions.While the energy resolution and detection efficiency of gamma-ray scintillation detector are important parameters in the studies.In order to develop a high-energy gamma detector based on cesium iodide crystals,experimental measurements and Geant4 simulations are carried out and their results compared with each other to investigate the feasibility and performance improvement of using the crystal detector to measure high energy gamma-rays in this thesis.This thesis is mainly consisted of five parts.The first part introduces the research background,the main purpose of the subject,the comparison of different crystal features and the cause of final selection of cesium iodide crystals.The second part is the experimental measurements and offline data analysis work using one detector unit to detect gamma rays of standard radioactive sources,then obtain the detection efficiency curve for discrete gamma energy.In the third part,we simulate the process of detecting the gamma ray with different energy and angular distribution,introducing the Monte Carlo simulation tool--Geant4.The process of the detector modeled in Geant4,physical process,simulating data and key parameter settings are described in detail.The detection result of low-energy gamma-rays obtained in the final simulation is in good agreement with the experimental results,then we give a further prediction on detection efficiency for high-energy gamma-rays.At the same time,a preliminary simulation of the visible light generation and transport process in the crystal of cesium iodide is shown in the third part.The fourth part covers the performance simulation and analysis of the detector array composed by 42 detector units.The detection curve predicts the detector array response to gamma measurements in the future giant resonance gamma measurements.Next in order to optimize the detector configuration,we show a comparison of three structures’detection efficiency curves.In the fifth part,we mainly introduce the proton capture nuclear reaction experiment on the electrostatic accelerator.The calibration energy range for the CsI detector can be expented to 8.9MeV,using the higher energy gamma generated by the ²⁷Al（p,γ）²⁸Si reaction.The experimental setup,online measurement processing,data operation and results are introduced in detail.Finally,the summary and prospect of the topic on the measuring high energy gamma using scintillation crystal detector are proposed.Some suggestions are raised according to the unresolved difficulties during the course of the project.By conducting the study of measuring high-energy gamma-rays with cesium iodide crystals,we have mastered the experiment and simulation methods for the scintillation crystal.The detection efficiency curves of cesium iodide detection units and array for high-energy gamma are obtained,and the simulation and experimental results are in good agreement.The consequences of visible light simulation,array detector multiplicity of trigger,data processing and gamma detector array configuration improvements provide an important reference for the measurement of high-energy gamma-rays.