Strategies and first measurements for a directional dark matter detector in diamond

During the next decade, direct detection searches for weakly interacting massive particles (WIMP) dark matter (DM) will likely reach the "neutrino floor," the sensitivity at which they will be limited by coherent scattering of solar neutrinos. Directional detection would enable WIMP searches beyond this limit by discriminating events of solar and galactic origin. In a crystalline detector, WIMP- and neutrino-induced nuclear recoils would leave a sub-micron track of lattice damage, giving a durable signal for the incoming particle's direction. Measuring such a track could thus provide directional discrimination in a solid-state detector. Diamond has been proposed as a next-generation WIMP detector because of its sensitivity to low-mass DM candidates, as well as its excellent cryogenic semiconductor properties. We are developing methods for directional detection in a diamond detector. Spectroscopy of quantum defects such as nitrogen vacancy (NV) centers allows detection of crystal damage via the strain induced in the crystal lattice, while methods such as X-ray diffraction allow nanoscale mapping of crystal structure. In this talk, we present the proposed directional detection principle as well as an overview of recent experimental results.