The Daya Bay Reactor Neutrino Experiment

The Daya Bay reactor neutrino experiment is a high sensitivity experiment designed to determine the last unknown neutrino mixing angle theta₁₃ by measuring disappearance of reactor antineutrinos emitted from six 2.9 GW_th reactors at the Daya Bay Nuclear Power Station. There are eight identical Gd-loaded liquid scintillator detectors deployed in two near (flux-weighted baseline 512 $m$ and 561 $m$) and one far (1579 $m$) underground experimental halls to detect the inverse beta decay interaction. This dissertation describes the Daya Bay Experiment and individual contributions to this experiment. Chapter 1 reviews the history of the neutrino and the neutrino oscillation phenomena. The reactor based neutrino experiments in different times are described in this chapter in detail. It presents the motivation of the Daya Bay Experiment. In Chapter 2, the neutrino detection method and the theta₁₃ relative measurement method are introduced. This chapter focuses on the design of the Daya Bay Experiment, including antineutrino detector, calibration system, muon veto system and muon tagging system. Chapter 3 shows the design, development, construction, and assembly of Muon Pool PMT calibration system, and presents an algorithm of calculating the muon pool PMT timing offset values. Chapter 4 focuses on the manufacture, installation and commissioning of RPC HV system. Chapter 5 presents the analyses of the radioactive isotopes induced by comic muons. The Daya Bay detector energy response model is also described in detail. The relative rate analysis results exclude a zero value from sin²2theta₁₃ with a significance of 7.7 standard deviation using 139 days of data, 28909 (205308) antineutrino candidates which were recorded at the far hall (near halls) and shows sin²2theta₁₃ = 0.089pm0.011 in a three-neutrino framework. A combined analysis of the overline nu_e rates and energy spectra based on the detector energy response model improved measurement of the mixing angle sin²2theta₁₃ = 0.090^+0.008_-0.009 by using 217 days of data, 41589 (203809 and 92912) antineutrino candidates were detected in the far hall (near halls). Also the first direct measurement of the overline nu_e mass-squared difference |Delta m²_ee|= (2.59^+0.19_-0.20)times10^-3 eV². It is consistent with |Delta m²_mumu| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Physics

Department dc:contributor.department

Physics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2014

Author dc:creator

• Meng, Yue

Chair dc:contributor.committeechair

• Link, Jonathan M.

Committee members dc:contributor.committeemember

• Pitt, Mark L.
• Huber, Patrick
• Soghomonian, Victoria G.

• Neutrino Oscillation
• PMT Timing Calibration
• Cosmogenic Isotopes
• Energy Response Model

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:3670

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/50534