The main goal of the Double Chooz reactor neutrino experiment is a precision measurement of the neutrino mixing angle Theta13. This smallest of the three known mixing angles is determined from the disappearance of electron antineutrinos emitted by two nuclear reactors in Chooz, France. Neutrino interactions with the protons of an organic liquid scintillator produce a coincidence signal consisting of the energy depositions of a prompt positron and a delayed neutron allowing efficient background suppression. The reactor neutrino flux is measured in two detectors at different baselines to the source. The near detector at 400 m from the reactors provides a reference measurement almost without an oscillation effect. The far detector at 1.05 km distance is located close to the first oscillation minimum. Recent two detector results will be presented. A precise measurement of Theta13 with the running reactor neutrino experiments is a crucial input for upcoming projects sensitive to CP-violation and atmospheric mass hierarchy observables.
Max Planck Institute for Nuclear Physics