Performance and improvements of the double Chooz inner muon vetos

Double Chooz is a reactor neutrino experiment, which aims to measure the neutrino mixing angle θ13 with high precision. Therefore a good knowledge of all background processes is mandatory. For this purpose the Double Chooz detectors are equipped with an active liquid scintillator based muon veto system, the Inner Veto. This veto was designed and installed by the University of Tuebingen. This thesis begins with a short introduction to the physical aspects of the neutrino oscillations. In the following chapter several reactor neutrino experiments are presented with the focus on the Double Chooz experiment. Results of Monte Carlo simulation testing possible improvements for the near detector are shown as well. The charge spectrum of the Inner Veto of the far detector is compared to Monte Carlo simulations. The total event is determined and contrasted with the estimation of dark noise of the used PMTs and radioactive impurities. The azimuth and polar angle distributions of muons reconstructed by two individual algorithms are compared to Monte Carlo simulation. The time distribution of muon classified events before neutrino candidates is analysed, and a new veto time window after muons is presented. The time stability of scintillators in the far detector is investigated, and possible influences to it are tested. At the end the reactor neutrino experiment JUNO is presented, and the results of a performed Monte Carlo simulation are shown, in which the dimensions of the JUNO-water shielding was varied to minimise the amount of muon induced neutron captures in the target region.