Neutrino and astroparticle physics with P-type point contact high purity germanium detectors

The recent development of large mass, low noise P-type point contact (PPC) high purity germanium detectors has opened up a number of new opportunities for experiments in neutrino and astroparticle physics. Several of these experiments have been performed with the earliest prototypes. They are described in this thesis. A measurement for the quenching factor for sub-keV nuclear recoils in germanium detectors is presented. Also discussed is an assessment of the low energy backgrounds at a nuclear power reactor along with the progress that has been achieved towards a measurement of coherent neutrino-nuclear scattering. Using the brief exposure of the detector to a high flux of reactor neutrinos, a limit is placed on the magnitude of a neutrino magnetic moment and a projected limit that can be achieved with a more complete experiment is discussed. A limit is also placed on the magnitude of a continuous energy deposition by reactor neutrinos in the germanium detector. Using the low background data that were obtained at the reactor, limits on light WIMPs as well as dark galactic pseudoscalars are presented, which constrain the physical explanation for a claimed observation of dark matter by the DAMA collaboration. As PPC detectors have been chosen as the preferred detector for the 60 kg Majorana demonstrator double beta decay experiment, projected limits on light WIMPs and dark pseudoscalars are also presented. Finally, bounds are placed on the lifetime of the electron for the "invisible" decay into three neutrinos, and projected limits for such a search using the 60 kg Majorana demonstrator are also presented.