Ancient Minerals as Dark Matter Detectors

The emerging field of "paleo-detection" offers the potential to reconstruct variations in cosmic-ray flux throughout Earth’s history, probe the past star formation rate of the Milky Way, and achieve exposures competitive with large-scale (ton-year) real-time dark matter detectors. Ancient minerals from deep underground, protected over gigayear timescales from cosmogenic backgrounds by the overburden of the earth, preserve evidence of interactions with astronomical and atmospheric neutrinos as well as WIMP dark matter. With proper sample selection, background modeling, and microscopy, defects in the crystal lattice structure of minerals (nuclear recoil damage tracks) can reveal evidence of these rare particle interactions. At the University of Michigan, we are prototyping paleo-detectors from quartz (SiO2) and olivine ((Mg, Fe)2SiO4) taken from deep underground environments. This talk will explore the feasibility of the paleo-detection technique for dark matter detection, and discuss current efforts at the University of Michigan, from obtaining and characterizing a natural mineral sample, to the measurement and analysis of tracks.