26 research outputs found
Physics of Extremely High Energy Cosmic Rays
Over the last third of the century, a few tens of events, detected by
ground-based cosmic ray detectors, have opened a new window in the field of
high-energy astrophysics. These events have macroscopic energies, unobserved
sources, an unknown chemical composition and a production and transport
mechanism yet to be explained. With a flux as low as one particle per century
per square kilometer, only dedicated detectors with huge apertures can bring in
the high-quality and statistically significant data needed to answer those
questions. In this article, we review the present status of the field both from
an experimental and theoretical point of view. Special attention is given to
the next generation of detectors devoted to the thorough exploration of the
highest energy rangesComment: 43 pages, 12 figures, submitted to International Journal of Modern
Physics
Cosmic Rays above eV
We briefly review the status of cosmic ray studies between eV and
the highest observed energies, namely a few times eV. Because of the
rather low incident fluxes in this energy range, the studies mostly rely on
ground based, large aperture detectors reconstructing the cosmic ray's
properties through the detection of the air-showers they generate by
interacting with the atmosphere. We stress the fact that many issues such as
the chemical composition of the cosmic rays, their acceleration mechanisms, the
structures displayed in their energy spectrum are mostly open questions which
may be answered by the next generation of experiments.Comment: 11 pages, 5 figures, Latex2e, one reference modifie
Histoire dâun projet singulier : lâobservatoire Pierre Auger
History of a Singular Project : The Pierre Auger Observatory The Pierre Auger Observatory is a giant cosmic ray detector presently in construction in Argentina. Several hundreds of scientists coming from fifteen countries (half of which from Europe) have been working for more than ten years to the design and construction of this unique detector. The aim of the project is to understand the origin and nature of cosmic rays detected in very small numbers whose energies exceed by a factor of several hundreds of millions those of the particles accelerated by the most performing accelerators ever built by men. The article summarizes the genesis and the scientific stakes of this project in which France, and more specifically the CNRS, played a major role