Manual calibration system for Daya Bay Reactor Neutrino Experiment

The Daya Bay Reactor Neutrino Experiment has measured the last unknown neutrino mixing angle, θ 13 , to be non-zero at the 7.7σ level. This is the most precise measurement to θ 13 to date [1,2]. To further enhance the understanding of the response of the antineutrino detectors (ADs), a detailed calibration of an AD with the Manual Calibration System (MCS) was undertaken during the summer 2012 shutdown. The MCS is capable of placing a radioactive source with a positional accuracy of 25 mm in R direction, 12 mm in Z axis and 0.5° in Φ direction. A detailed description of the MCS is presented followed by a summary of its performance in the AD calibration run.