The Daya Bay Experiment III: Design, Construction, and Calibration of the Active Water Shield

The Daya Bay Experiment aims to measure the neutrino mixing angle $\theta_{13}$ precisely. In order to achieve the sensitivity of 0.01 in $\sin^2(2\theta_{13})$, muon has to be identified with the design efficiency of 99.5\%. This talk will give an overview on the Daya Bay muon system: Water Cherenkov Detector, and Resistive Plate Chambers (RPCs), its construction and calibration. Performance on real data will be discussed.