Probing ancient cosmic messengers with paleodetectors

Natural minerals, through their ability to record particle interactions over geological timescales, are emerging as a novel tool for astroparticle physics. The paleo-detector concept leverages the nanometer to micrometer-scale damage tracks left by nuclear recoils to search for rare events like dark matter and neutrinos. Our work takes a unique approach by treating the tracks from cosmic ray muons, typically a background for other paleo-detector studies, as the primary signal for probing the high-energy astrophysical history of our galaxy. In the seminar, I will first show our published work establishing the viability of this technique using evaporite minerals from the Messinian Salinity Crisis (~6 Myr ago). I will then present for the first time our new phenomenological study on a different geological scenario: olivine xenoliths from the Chaîne des Puys volcanic field in France. This region provides not a single data point, but a «chronosequence» of samples with ages ranging from 7,000 to 40,000 years. By analyzing samples with different exposure ages, we can move from a single, time-integrated measurement to a time-resolved study of the cosmic ray flux. This new approach transforms the paleo-detector concept into a time-domain observatory for high-energy astrophysics. I will also talk about PRImuS, the experimental extension of these phenomenological works.