A research program is described leading to the exploitation of a new type of radiation detector, a large-mass p-type Germanium diode with a modified electrode structure that results in an ultra-low energy threshold and advanced pulse-shape discrimination capabilities, while preserving an optimal energy resolution.
It is proposed to use such devices for numerous applications in a variety of areas: for instance, the existing prototype is the first detector with sufficient mass and a demonstrated sensitivity to very low-energy (subkeV) nuclear recoils to allow a first measurement of coherent neutrino-nucleus scattering in a reactor experiment. The same experiment would lead to an improved sensitivity to a finite neutrino magnetic moment. Many exciting opportunities for such a coherent neutrino detector technology exist, both in fundamental and applied Physics. Searches would also be possible for several types of Weakly Interacting Massive Particle dark matter candidates presently beyond the reach of any existing detector. Finally, the design performs ideally within the context of next-generation double beta decay searches using enriched Ge diodes (MAJORANA, GERDA), by accomplishing an efficient background rejection within a single-channel device, avoiding the complications and risks involved in using multi-channel segmented detectors.
Support is requested for a multi-year R&D program to further characterize the fabrication technique of this novel type of radiation detector, by building an additional six diodes, the intent being to develop the best possible design option for MAJORANA. Modest support is requested for immediate prototype deployment at the Columbia Generating Station, a 3.5 GWt boiling water reactor in Richland (WA), aiming at a first measurement of the coherent neutrino nuclear scattering cross-section and an improved (anti) neutrino magnetic moment sensitivity.
This research will continue to provide multiple opportunities for undergraduate involvement. The prospects and plans for a realistic deployment of small arrays of modified electrode detectors as reactor monitoring devices (non-proliferation safeguards) are also being developed.
