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15-Cosmic rays (Composition (Relatively smaller number of protons may be…
15-Cosmic rays
Composition
Relative to the general level of abundance of elements wit Z>1, protons are less abundant in cosmic rays
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higher abundance in the region 21<Z<25 by factor of e2-e3 (scantium,titanium,vanadium,chromium,manganese)
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No antihadrons-essentially no antimatter in primary cosmic rays, so likely no galaxies of antimatter
Electrons are about 1% as abundant an nuclei, and of these about 10% are positrons
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Detecting CRs
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Example- AUGER
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1600 detector stations, 1.5 km spacing, 3000 square km
4 eyes with 6 telescopes each, giving 24 telescopes
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Spallation
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C and O can be broken up into Li, Be, B
Fe can be broken up into Sc, Ti, V, Cr, Mn
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Relevance to course
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isotopes of low A elements (Li, Be and B) have higher abundances on earth than expected
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Sources
Solar cosmic rays
mainly protons, very low energies, flux changes with solar activity
Anomalous
outer reaches of solar system, low energy
Galactic
Higher energies, may be accelerated by supernova remnants
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Energy dependance
Fermi mechanism is where macroscopic kinetic energy of a moving magnetised plasma is transferred to individual charged particles
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Primary Cosmic rays
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Nucleus of hydrogen or a heavier element, up to iron
Sources
link between relative cosmic ray abundance and ionisation potential suggests cosmic ray seed material has cooled before acceleration
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