Composition of cosmic rays and optics for fluorescence telescopes

The Pierre Auger Observatory is the largest astroparticle physics experiment in the world. It registers cosmic particles of energies far beyond the reach of any terrestrial accelerator over an area of 3000 sq. km of Argentine pampa. The aim of the Observatory is to determine the energy spectrum and arrival directions of the particles and answer the question of their origin - whether they are produced in unknown “cosmic accelerators” or during the decay of hypothetical dark matter particles. The thesis will investigate the relationship between the accuracy of the measurement of the depth of the maximum of the development of the showers caused by the cosmic rays in the atmosphere and the determination of their composition. The aim will be to understand the requirements for the optical systems of the fluorescence telescopes in this regard. The work fits thematically within the program of the Pierre Auger Observatory and its future FAST extension.