Interactions between Čerenkov radiation and atmosphere: simulations for the volcanic muography at Mount Etna

The role of Earth's atmosphere in the detection of high energy radiation from cosmic sources lies in the generation of Cherenkov radiation from associated charged particles. The calibration of Imaging Atmospheric Cherenkov Telescopes (IACTs) passes through the study and reconstruction of cones of Cherenkov light produced by muons in the form of rings. The italian project ASTRI located at Mount Etna is a prototype of telescope for future worldwide experiment Cherenkov Telescope Array. Under current investigation is the possibility to offer an additional expendability for such prototype telescope, namely in the volcanic muography, a technique of muon ring reconstruction aimed at non-invasive observations of the interiors of volcanoes. Current state of work has reached the stage of successful simulations; horizontally travelling cosmic muons traversing the volcano reflect the distribution of internal matter via their number density, a quantity retrieved through techniques of muon ring reconstruction. A proper detailing of the interactions between the UV photons of Cherenkov light and the atmospheric air between the volcano and the telescope is still lacking, the current model making use of a standard air from (NASA, 1976) for the basic needs of the model, while neglecting any scattering or absorption process. In this work I provide coverage of the atmospheric properties of the ASTRI site, parameterizing the refractive index of air, and integrating the results into the already existing simulation framework, carried out in the particle physics GEANT4 toolkit from CERN. A toy model in the same framework will expose the role of Rayleigh scattering and aerosol absorption and scattering, wich I have modeled around the troposheric conditions at the site from relevant meteorological historic datasets. This thesis aims at mirroring the academic career of the author, swaying between Atmospheric Physics and Astrophysics, ideally providing for a bridge between the two disciplines.