W. L. Zhong

Assembly and Installation of the Daya Bay Antineutrino Detectors

The Daya Bay reactor antineutrino experiment is designed to make a precision measurement of the neutrino mixing angle θ_(13), and recently made the definitive discovery of its non-zero value. It utilizes a set of eight, functionally identical antineutrino detectors to measure the reactor flux and spectrum at baselines of ~ 300–2000 m from the Daya Bay and Ling Ao Nuclear Power Plants. The Daya Bay antineutrino detectors were built in an above-ground facility and deployed side-by-side at three underground experimental sites near and far from the nuclear reactors. This configuration allows the experiment to make a precision measurement of reactor antineutrino disappearance over km-long baselines and reduces relative systematic uncertainties between detectors and nuclear reactors. This paper describes the assembly and installation of the Daya Bay antineutrino detectors.

Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Abstract Electron antineutrinos from six 2.9 GWth reactors are detected with six detectors deployed in two near and one far underground experimental halls at Daya Bay. Using 217 days of data, more than 300,000 antineutrino candidates were detected in the three halls. In this talk, a measurement of absolute reactor antineutrino flux and spectrum is described, including comparisons of the measurement to predictions based on different reactor antineutrino flux models. A method for extracting a generic reactor antineutrino spectrum from the measured absolute antineutrino spectrum is presented, which could be used in place of current reactor antineutrino flux models.

Waterproofed Photomultiplier Tube Assemblies for the Daya Bay Reactor Neutrino Experiment

In the Daya Bay Reactor Neutrino Experiment 960 20-cm-diameter waterproof photomultiplier tubes are used to instrument three water pools as Cherenkov detectors for detecting cosmic ray muons. Of these 960 photomultiplier tubes, 341 are recycled from the MACRO experiment. A systematic program was undertaken to refurbish them as waterproof assemblies. In the context of passing the water leakage check, a success rate better than 97% was achieved. Details of the design, fabrication, testing, operation, and performance of these waterproofed photomultiplier-tube assemblies are presented