منابع مشابه
Cosmic X-ray Sources
The atmosphere of the Earth is opaque to most wavelengths of light in the infrared, in the ultraviolet and in the X-rays. Due to this fact observation of celestial objects in X-rays (in the range of energies from 0.5 to 20 keV) must be carried out outside the atmosphere at altitudes greater than 100 kilometers, namely from space. The development of X-ray astronomy had therefore to await the dev...
متن کاملCosmic-Ray Spectra in Interstellar Space
At energies below ~300 MeV/nuc our knowledge of cosmic-ray spectra outside the heliosphere is obscured by the energy loss that cosmic rays experience during transport through the heliosphere into the inner solar system. This paper compares measurements of secondary electron-capture isotope abundances and cosmic-ray spectra from ACE with a simple model of interstellar propagation and solar modul...
متن کاملTime Delays in Cosmic Ray Propagation
Cosmic Rays (CR) travel at speeds essentially indistinguishable from the speed of light. However whilst travelling through magnetic fields, both regular and turbulent, they are delayed behind the light since they are usually charged particles and their paths are not linear. Those delays can be so long that they are an impediment to correctly identifying sources which may be variable in time. Fu...
متن کاملCosmic X-ray Sources - Ii
During the first discovery flight of ScoX-1 in 1962 an isotropic X-ray background was observed (Giacconi et al. 1962). This had immediate consequences for cosmology. Hoyle’s Hot Universe continuous creation theory could not account for this emission, and this created a major difficulty for the theory as a whole. Burbidge suggested that the emission could be due to the sum of unresolved galaxies...
متن کاملsimulation and comparison of radiology x-ray spectra
monte carlo method is a very accurate method to optimize medical diagnostic radiology spectra and simulation of radiation transportation. using mcnp code, radiology and mammography attenuated x-rayspectraweresimulated.the ipem report number 78 was used as a reference to compare with the geant4 and mcnp simulations because of its popularity and wide availability. the results of geant4 in 40kev s...
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ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1972
ISSN: 0252-9211
DOI: 10.1017/s0252921100090047