The Double Chooz Experiment

Abstract

Double Chooz is a reactor ν̄e-disappearance experiment situated at the commercial nuclear power plant of Chooz in northern France. The experiment aims for the revelation of the last unknown mixing angle Θ13 as a part of the neutrino mixing matrix or the improvement of the upper limit for sin2(2Θ13), which is currently < 0.14 (90% CL). A newly developed gadolinium-loaded liquid scintillator as target allows the detection of electron-anti-neutrinos (ν̄e) using the inverse beta decay and its distinct decay pattern (ν̄e + p → e+ +n). Double Chooz uses two identical detectors at different distances in order to reduce systematic uncertainties. This will allow, after a data taking phase of 4 years, an improvement on sin2(2Θ13) down to < 0.03 (90% CL). The first (far) detector has successfully been installed and filled, and takes data since April of 2011. A preliminary analysis of first 120 days revealed about 4000 Neutrino-candidates and a stable detector-setup with low backgrounds. The commissioning of the second (near) detector is expected for the beginning of 2013 and will provide maximum sensitivity for the experiment.