Daya Bay Antineutrino Detectors Research Articles

Energy response model of Daya Bay antineutrino detectors

Energy response model of Daya Bay antineutrino detectors

Automated calibration system for a high-precision measurement of neutrino mixing angle θ13 with the Daya Bay antineutrino detectors

We describe the automated calibration system for the antineutrino detectors in the Daya Bay Neutrino Experiment. This system consists of 24 identical units instrumented on 8 identical 20-ton liquid scintillator detectors. Each unit is a fully automated robotic system capable of deploying an LED and various radioactive sources into the detector along given vertical axes. Selected results from performance studies of the calibration system are reported.

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 θ13, 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 spectrumat 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.

Target mass monitoring and instrumentation in the Daya Bay antineutrino detectors

The Daya Bay experiment measures sin 22θ13 using functionally identical antineutrino detectors located at distances of 300 to 2000 meters from the Daya Bay nuclear power complex.Each detector consists of three nested fluid volumes surrounded by photomultiplier tubes.These volumes are coupled to overflow tanks on top of the detector to allow for thermal expansion of the liquid.Antineutrinos are detected through the inverse beta decay reaction on the proton-rich scintillator target.A precise and continuous measurement of the detector's central target mass is achieved by monitoring the the fluid level in the overflow tanks with cameras and ultrasonic and capacitive sensors.In addition, the monitoring system records detector temperature and levelness at multiple positions.This monitoring information allows the precise determination of the detectors' effective number of target protons during data taking.We present the design, calibration, installation and in-situ tests of the Daya Bay real-time antineutrino detector monitoring sensors and readout electronics.

Daya Bay Antineutrino Detector gas system

The Daya Bay Antineutrino Detector gas system is designed to protect the liquid scintillator targets of the antineutrino detectors against degradation and contamination from exposure to ambient laboratory air. The gas system is also used to monitor the leak tightness of the antineutrino detector assembly. The cover gas system constantly flushes the gas volumes above the liquid scintillator with dry nitrogen to minimize oxidation of the scintillator over the five year lifetime of the experiment. This constant flush also prevents the infiltration of radon or other contaminants into these detecting liquids keeping the internal backgrounds low. Since the Daya Bay antineutrino detectors are immersed in the large water pools of the muon veto system, othergas volumes are needed to protect vital detector cables or gas lines. These volumes are also purged with dry gas. Return gas is monitored for oxygen content and humidity to provide early warning of potentially damaging leaks. The design and performance of the Daya Bay Antineutrino Detector gas system is described.

Low-background monitoring cameras for the Daya Bay Antineutrino Detectors

The Daya Bay Reactor Neutrino Experiment is designed to measure the neutrino mixing angle θ13 to world-leading precision. The experiment deploys identical antineutrino detectors at distances of 400-1900 m from six reactors in Daya Bay, China. Each detector incorporates two general-purpose monitoring cameras to ensure their safe construction, transportation and operation. The cameras must meet usage goals while satisfying stringent constraints on radioactivity, materials compatibility, interference and reliability. This article describes the system design, integration, operation and performance.

Long-term testing and properties of acrylic for the Daya Bay antineutrino detectors

The Daya Bay reactor antineutrino experiment has recently measured the neutrino mixing parameter sin22θ13 by observing electron antineutrino disappearance over kilometer-scale baselines using six antineutrino detectors at near and far distances from reactor cores at the Daya Bay nuclear power complex. Liquid scintillator contained in transparent target vessels is used to detect electron antineutrinos via the inverse beta-decay reaction. The Daya Bay experiment will operate for about five years yielding a precision measurement of sin22θ13. We report on long-term studies of poly(methyl methacrylate) known as acrylic, which is the primary material used in the fabrication of the target vessels for the experiment's antineutrino detectors. In these studies, acrylic samples are subjected to gaseous and liquid environmental conditions similar to those experienced during construction, transport, and operation of the Daya Bay acrylic target vessels and detectors. Mechanical and optical stability of the acrylic as well as its interaction with detector liquids is reported.

Acrylic target vessels for a high-precision measurement of θ13 with the Daya Bay antineutrino detectors

This paper describes in detail the acrylic vessels used to encapsulate the target and gamma catcher regions in the Daya Bay experiment's first pair of antineutrino detectors. We give an overview of the design, fabrication, shipping, and installation of the acrylic vessels and their liquid overflow tanks. The acrylic quality assurance program and vessel characterization, which measures all geometric, optical, and material properties relevant to ν̄e detection at Daya Bay are summarized. This paper is the technical reference for the Daya Bay acrylic vessels and can provide guidance in the design and use of acrylic components in future neutrino or dark matter experiments.

Assembly and Installation of the Daya Bay Antineutrino Detectors

The Daya Bay Reactor Neutrino Experiment will make a precision measurement of sin 2 2θ 13 , the last unmeasured angle in the neutrino mass matrix in the next few years. Assembly is well underway with 4 of the planned 8 antineutrino detectors nearing completion. Assembly and installation of these antineutrino detectors is described.

High-Precision Measurement of the Target Mass of the Daya Bay Antineutrino Detectors

Abstract The Daya Bay experiment aims to measure the last unknown neutrino mixing angle, sin 2 (2θ 13 ), to a sensitivity of .01. The detection method requires “identical” near and far detectors each with a precisely known target mass on the order of 20,000 kg. A calibrated filling system able to fill the required 20,000 kg of Gd-doped scintillating liquid (GDLS) to an accuracy of