Studies Of Electron Neutrino Magnetic Moment And Radiative Decay Based On A Nuclear Reactor

Neutrino physics in the latest decade has undergone a rapid growth and has evolved into a discipline of relevance for various research fields, ranging from geophysics to astrophysics. This thesis reviews the history of neutrino physics, summarizes the present status of pure and applied neutrino physics.The Reactor neutrino experiment in Taipei has been introduced. The physics basis of the experiment and the measurement method have been described. The highlight of the experiment is due to its by far the lowest threshold than other reactor neutrino experiments. The threshold of the HPGe detector used in this expeiment is 5keV.It is well known that a nuclear reactor is a source of electron anti-neutrino in the low energy (<8MeV) range. Yet it can also emit electron neutrinos. Besides due to the decays of some odd-proton odd-neutron fission product nuclei, electron neutrinos are mostly associated with the electron capture process from neutron-activated products such as 51Cr, 55Fe and 59Ni which are components of reactor structure material. For further research work on reactor neutrino experiment, we performed the first simulation of the emissions of electron neutrinos from a nuclear reactor. A simplified model was constructed according to the reactor at the Kuo-Sheng power plant in Taipei. Details of the procedure of the simulation and calculation methods will be presented. The electron neutrino flux is derived from simulations, and the admixture ratio is about 2× 10-3 neutrinos per anti-neutrino.Analysis has been carried out to search for electron neutrino magnetic momentand radiative decays using the data acquired via the HPGe detector, combined with the simulation result. The program of data processing has been discussed in details. The physics idea of the data analysis has been illustrated. The upper limit of magnetic moment and the lower limit of radiative decay lifetime of reactor electronneutrinos has been found for the first time to be: μv ≤ 7.9 X 10-9μB (C.L. 68%),τ/mv≥1.3 s.eV-1 (C.L. 68%) respectively.Other possible reactor neutrino physics potential has been discussed. Experiments based on reactor neutrinos can, in principle, resolve basic puzzles set by current solar neutrino results and the underlying question of ve-flavor conversion.