PandaX-III high pressure xenon TPC for Neutrinoless Double Beta Decay search

Abstract The PandaX-III experiment uses high pressure Time Projection Chambers (TPCs) to search for Neutrinoless Double Beta Decay (NLDBD) of 136 Xe, with high energy resolution and sensitivity at the China Jin-Ping underground Laboratory II (CJPL-II). Fine-pitch Microbulk Micromegas will be used for charge amplification and readout in order to reconstruct both the energy and track of the NLDBD event. In the first phase of the experiment, the detector, which contains 200 kg of 90% 136 Xe enriched gas operated at 10 bar, will be immersed in a large water tank to ensure 5 m of water shielding. For the final phase, a ton-scale experiment with multiple TPCs will be constructed to improve the detection probability and sensitivity. A 20-kg scale prototype TPC with 7 Micromegas modules has been built to optimize the design of Micromegas readout modules, and to study the energy calibration of the gaseous TPC . The preliminary results of the PandaX-III prototype TPC will be also presented in this paper.