The Simulation And Data Reconstruction Of The Compton Telescope

The low capability?i.e.,detection sensitivity?of the conventional Compton telescope to observe?-rays in the medium energy region?200 keV-50 MeV?has resulted in important astrophysical information in this energy region not being fully exploited so far.Therefore,it is of great scientific importance to study a Compton telescope with high sensitivity.In this paper,a study of the high-sensitivity Compton telescope is carried out through the overall design,simulation,and algorithmic design of the data reconstruction of the Compton telescope.The overall design of the Compton telescope was carried out,and the structure of the Compton telescope was determined:the multi-layer double-sided silicon microstrip detector was used as the tracker in the upper of the telescope,the calorimeter in the lower of the telescope adopted a new structure,i.e.,a Cs I crystal array structure based on dual-ended readout,and the outermost anti-coincidence detector was composed of plastic scintillator.The overall simulation of the Compton telescope was carried out using the MEGAlib simulation software to determine the parameters of the sub-detectors and to simulate the interaction of the?-rays of different energies and the various background rays in the corresponding satellite orbits on the sub-detectors and to obtain simulation data.Methods of analyzing the simulated data and event reconstruction were studied.A method for solving clustering of interaction points,a method for identifying positron-electron pair events,and a quality factor method based on the Pearson correlation for reconstructing electronic tracks were designed.The test results showed that the algorithm performed well in data reconstruction.A CsI?-ray detector based on dual-ended readout was developed to serve as a detection unit of the calorimeter.The effects of packaging material,crystal size and photoconverters on the detector performance were investigated,and then the parameters of the detection unit were determined,i.e.,the detection unit was a 5×5×80mm³ crystal packaged with ESR,and used the silicon photomultiplier tube to read signals at both ends.The detection unit was tested by using 662ke V's?-rays,and then the performance parameters of the detection unit were obtained:energy resolution of 5.2%and longitudinal position resolution of about 5.2mm,which can meet the performance requirements of the Compton telescope for the calorimeter.The simulation results show that the Compton telescope designed in this paper has high sensitivity and excellent energy and angular resolution,i.e.the spectral sensitivity is overall better than 1×10^-6ph/cm²/s,the continuous spectral sensitivity is overall better than6×10^-6ph/cm²/s,the energy resolution is better than 4%near 1MeV and the angular resolution is overall less than 1 degree.The overall sensitivity is improved by 1 to 2 orders of magnitudes compared to conventional Compton telescopes,and the energy resolution and angular resolution are also greatly improved.Therefore,the overall design,simulation,and the study of the data reconstruction algorithm of the Compton telescope in this paper allows to obtain the high-sensitivity Compton telescope.The contents,methods and results of this paper can provide a good reference for the development of the next-generation Compton telescopes and the study of related technologies.