Phenomenology of primary cosmic rays. Propagation and acceleration mechanisms. Antiprotons and positrons in cosmic rays: secondary production and possible primary sources. Isotopic composition. Ultra-high-energy cosmic rays. Interaction of primary cosmic rays with the atmosphere and showers production. Experimental techniques for direct and indirect detection. Past experiments, missions currently underway and future projects for the measurement of cosmic rays.
M.S. Longair, ‘High Energy Astrophysics’, Cambridge University Press
D.H. Perkins, ‘Particle Astrophysics’, Oxford University Press
C. Grupen, B. Shwartz, ‘Particle Detectors’, Cambridge University Press
‘Cosmic Rays’ in ‘Review of Particle Physics’ , Particle Data Group
Learning Objectives
Knowledge and understanding: phenomenology of cosmic rays at all energies, main experimental methods for the detection of cosmic rays.
Ability to apply knowledge and understanding: calculation of cosmic ray fluxes, sizing of detectors.
Communication skills: ability to use a mathematical and physical language suitable for illustrating the models used in the description of the phenomena studied.
Prerequisites
Basic knowledge of particle physics
Teaching Methods
6 CFU
Classroom activities: 48 hours of frontal lessons.
Further information
Student reception:
E. Berti: by appointment (eugenio.berti (AT) unifi.it, 055-4572651) or at the end of each lesson.
M. Bongi: by appointment (massimo.bongi (AT) unifi.it, 055-4572299) or at the end of lesson.
Oral examination lasting about 1 hour. Students must be able to explain one of the topics presented during the lessons (even using slides, if needed) and answer additional questions. The expository and argumentative ability as well as the acquired knowledge will be evaluated.
Course program
Phenomenology of cosmic rays, measurement methods of cosmic ray fluxes, definition and use of the geometric factor. Influence of the Earth's magnetic field and solar activity on cosmic rays measured on Earth. Nuclear composition of cosmic rays, comparison with local abundances and equation of the transport of cosmic rays in the Galaxy. Simplified propagation model (leaky box model) and study of the characteristics of cosmic rays through measurements of relative abundances (amount of crossed matter, composition at the sources, spectral index, acceleration time and re-acceleration, mean lifetime of cosmic rays). Flux of electrons in cosmic rays, electromagnetic emission and the galactic halo. Flux of antimatter (antiprotons, positrons and search for antinuclei) and connections with possible primary sources. Energy balance of cosmic rays and Fermi acceleration mechanism in relation to supernovae physics. Ultra-high-energy cosmic rays. Phenomenology of atmospheric showers and detection techniques. Fermi mechanism and maximum achievable energy. The problem of acceleration to above-knee energies and explanation of the shape of the cosmic ray spectrum at the knee. The extragalactic propagation of particles and the expected GZK cutoff in the spectrum of cosmic rays of extreme energy. Discussion on possible extragalactic sources of extreme energy cosmic rays and on models for the interpretation of the data. Main experimental techniques used for the direct and indirect detection of cosmic rays. Principles of operation of magnetic spectrometers and electromagnetic / hadronic calorimeters used for direct detection. Operating principles of fluorescence, Cherenkov light and surface detectors used for indirect detection. Examples of cutting-edge experiments and main open problems for the improvement of direct and indirect cosmic ray detection methodologies.