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Abstract

The Double Chooz experiment, analysing the reactor antineutrinos signal from the nuclear power plant in Chooz (France), aims for a precision measurement of the neutrino mixing angle θ13 with the new data collected at the near and far detectors. An accurate and precisely known detection efficiency of the electron antineutrino interaction ve + p -> e+ + n, called inverse beta decay (IBD), is required in order to reach that goal. The correlated signal caused by the IBD interaction requires a good estimation of the neutron detection e_ciency, dominant uncertainty in the θ13 estimation. Among other calibration methods, the deployment of the 252Cf radioactive source along the detectors' inner volumes is used to understand the behaviour of the neutron captures in the detectors. The recently collected 252Cf data and Monte Carlo simulations are studied along this thesis. The fraction of n-captures on Gadolinium (atoms loaded in the neutrino target) has been estimated to prove the time stability and consistency between detectors, and to study the behaviour of the neutron captures at the inner volume borders. These results and the performed estimation of the systematic uncertainties of the neutron capture efficiency provide a crucial input for the antineutrino oscillation analysis with two detectors.