Mr Zhongquan Zhang (Shandong University)
Large High Altitude Air Shower Observation (LHAASO) is a proposed cosmic ray experiment which will be built in Daocheng, Sichuan Province of China, 4400m in altitude. One square kilometer detector array (KM2A) is focused on the exploring for origin of cosmic ray and studying on the `knee` physics, etc, which consists of 5242 electromagnetic particle detectors (EDs) and 1146 muon detectors (MDs). ED array is designed to measure the densities and arrival times of their secondary particles in the extensive air showers (EASs). ED is plastic scintillation detector, in which a layer of 5mm-thick lead installed to increase the detection efficiency of secondary gammas. The performances of ED have been studied, such as detection efficiency, time resolution. Especially, a wide dynamic particle density range from 1 to 10000particles/m2 is realized with the design of PMT divider.