Thèse de doctorat en Physique des particules
Soutenue le 17-01-2011
à Lyon 1 en cotutelle avec l'Università degli studi di Milano - Bicocca , dans le cadre de École doctorale de Physique et Astrophysique de Lyon , en partenariat avec Institut de Physique Nucléaire de Lyon (laboratoire) .
Le président du jury était Stefano Ragazzi.
Pas de résumé en français
In experiments looking for rare events, like neutrinoless double beta decay (DBD0v) and dark matter search (DM), one of the main issues is to increase the experimental sensitivity through the material selection and production. In the specific the background contribution coming from the materials used for the detector realization has to be minimized. Moreover the net reduction of the background produced by the bulk part of the apparatus has raised concerns about the background contribution coming from the surfaces. Many procedures and techniques were developed during the last years in order to remove and to minimize the presence of possible contaminants on detector surfaces. To succeed in this strategy a big effort was put in defining all possible mechanisms that lead to surface contaminations, as well as specific cleaning procedures, which are able to reduce and control the surface radioactivity. The presence in air and gases of possible radioactive elements that can stick on the detector surfaces can lead to a recontamination process that will vanish all the applied cleaning procedures. Here is presented and analyzed the contribution to the background of rare events experiments like CUORE (DBD0v) and EDELWEISS (DM) produced by an exposure of their detector components to a big activity of 222Rn, radioactive daughter isotope from the 238U chain