Problems Related to Interplanetary Matter (1961) / Chapter Skim
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THE HIGH ENERGY COSMIC RAY SPECTRUM
THE HIGH ENERGY COSMIC RAY SPECTRUM
Pages 53-57
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From page 53... ...
At higher energies the cosmic ray events are too rare to be detected directly, so scintillation counters are employed to detect electrons produced in the air shower. In this case, the number of electrons passing any level of the atmosphere provides a good measure of the energy Df the primary without too much dependence on the model of multiple meson production which is assumed.
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From page 54... ...
At higher energies little is known about relative abundances or energy spectra of the medium and heavy weight nuclides due to the scarcity of such events. It does appear, however, that the total medium-weight particles are about 2-1/2 to 3 orders of magnitude less abundant than protons, and that the heavy weight nuclides are about 3-1/2 orders of magnitude less abundant throughout the energy range from 1 Bev up to a few hundred Bev.
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From page 55... ...
There is a possibility of gaining valuable information on the structure and composition of our Galaxy by looking for pure electron-photon showers caused by energetic .y-rays that arose when a high energy particle struck quiet matter at some distant point in the Galaxy. These pure photon showers would be free of all particles but electrons and photons because the probability of photonuclear reactions is truly negligible compared to ionizations.
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From page 56... ...
It is easy to understand why a power law spectrum results from such an equation if injection is continuous, and it is also plain that the highest energy particles will be the oldest. Variations in wave structure, relative velocities and wave spacing, magnetic field topology, damping parameters and the energies of injected particles have been employed to explain the observed energy spectrum for primary cosmic rays.
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From page 57... ...
, for example, suggests that the cosmic ray flux is a result solely of supernovae acceleration and diffusion throughout the galactic halo; this averts the first difficulty mentioned above but not the second and third, and it introduces many problems of its own (such as an expected cutoff in the proton spectrum at 1015 ev)
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