The use of paleo-detectors to investigate cosmic-ray fluxes throughout the history of Earth

The measurement of the flux of cosmic rays in the past could give some important information about the sources of cosmic rays, the evolution of the neighborhood of the Solar System in the Galaxy and the Galaxy itself. It could also inform our understanding of key events in the Earth’s history such as mass extinctions. The paleo-detector technique proposes to investigate the traces left in natural minerals by energetic particles over geological timescales. A number of works have already suggested the use of paleo-detectors to measure weakly interacting particles such as dark matter constituent particles and neutrinos. Here, we propose for the first time to use paleo-detectors to directly detect secondary cosmic rays. The advantage of this approach is that cosmic rays can be shielded, and thus, in rocks with a particular history, we can measure the flux of cosmic rays at a specific moment in time rather than integrated since the initial formation of the target mineral. For example, evaporites produced in the desiccation of the Mediterranean sea during the Messinian salinity crisis have been exposed to cosmic rays for a very specific (and known) period of time before being submerged by a km-deep overburden of water, possibly retaining information about the flux during the exposure period. In this work, we show the challenges of this kind of study, its proposed targets and the track detection techniques.