Study On The Performance Of LHAASO-KM2A Experiment And The Expected Observation On Gamma Ray Astronomy

The origin of cosmic rays, acceleration and its propagation are uncertain up to now, this is because the spreading of charged particles in the galaxy will be effected by the magnetic field, so cosmic rays propagation direction will be changed. Neutral gamma ray is not affected by the magnetic field and it carries the important information of cosmic rays, so we can determine the position of the cosmic ray source through the gamma ray direction and understand the mysteries of origin of cosmic rays.In recent decades, high energy gamma astronomical made a great progress, in order to be able to determine the high energy gamma radiation mechanism and search cosmic ray source, the Chinese academy of sciences institute of High energy physics puts forward LHAASO (Large High Altitude Air Shower Observatory) project, and KM2A (one km2array) is one of the main parts of LHAASO project, composing of5341charged particle detectors(ED) and1221muon detectors(MD).The purpose of KM2A is to explore the origin of cosmic rays, acceleration and the spreading of cosmic rays, carry out scanning of gamma source and provide high precise measurement of the gamma ray spectrum, explore radiation mechanism of high-energy particle acceleration, measure single component of cosmic ray spectrum, and confirm the position of "knee"The work of this Master’s thesis is the simulation of KM2A and studying the gamma ray astronomy.The first chapter introduces the basic problems of the cosmic rays and the gamma-ray generation mechanism and observation status.The second chapter mainly introduces the main setting of LHAASO-KM2A, and the simulation results have good agreement with prototype array which has already running at YBJ.The third chapter introduces the basic performance of KM2A array(like threshold energy,energy resolution,angular resolution,core position resolution and so on). Moreover, by means of WCDA (Water Cherenkov Detector Array) which is capable of detecting muons, the sensitivity of KM2Ahas been improved significantly. The fourth chapter is mainly to discuss the analysis of the different sources, such as Crab Nebula, Tycho, MGRO J1908+06and IC443; we give expected spectrum of gamma ray with different energy cutoff measured by the KM2A array.The fifth chapter is full of a summary.The work of this Master’s thesis makes a deep step to the simulation of KM2A array and improves the sensitivity of KM2A array, so we can get the best ratio of price and performance for KM2A array.We also give the best expectation of gamma ray astronomy with KM2A array.