Experimental study of neutrino-electron scattering at low energy with the Munu experiment

This thesis is based on the experimental study of electron antineutrino - electron (v_e - e) elastic scattering at low energy with the MUNU experiment. The aim of this experiment is to study in particular the magnetic moment of the neutrino. The MUNU experiment uses a nuclear reactor as a neutrino source. The neutrinos are detected by using a gas Time Projection Chamber (TPC). The electrons of the TPC filling gas (CF4) are the target for .e e Ë scattering. In each interaction the direction of the recoiling electron can be reconstructed together with its energy. The incoming neutrino energy is reconstructed by using the recoil energy of electrons together with its scattering angle. The background is isotropic, while the signal is only in the forward neutrino direction. In this work is presented analysis of data recorded by the MUNU detector at two different gas pressures: 1-bar and 3-bar. The energy resolution of the detector at 1-bar is found to be about a factor of two better than the measured at 3-bar. The neutrino candidates, selected with the help of a visual scanning procedure undergo two different analyses Forward-Backward and Forward-Normalized Background. At 1-bar pressure we show, for the first time, a measurement of the neutrino cross section down to 400 keV, i.e. electron recoil energy down to 200 keV. For operation of 3-bar and above 900 keV the measured electron recoil spectrum is compared with the predicted one from the weak interactions. The measured limit of magnetic moment of electron antineutrino: Ê

Thèse de doctorat : Université de Neuchâtel : 2004 ; 1777